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Rosenfield MF, Jakovac CC, Vieira DLM, Poorter L, Brancalion PHS, Vieira ICG, de Almeida DRA, Massoca P, Schietti J, Albernaz ALM, Ferreira MJ, Mesquita RCG. Ecological integrity of tropical secondary forests: concepts and indicators. Biol Rev Camb Philos Soc 2023; 98:662-676. [PMID: 36453621 DOI: 10.1111/brv.12924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 11/15/2022] [Accepted: 11/17/2022] [Indexed: 12/03/2022]
Abstract
Naturally regenerating forests or secondary forests (SFs) are a promising strategy for restoring large expanses of tropical forests at low cost and with high environmental benefits. This expectation is supported by the high resilience of tropical forests after natural disturbances, yet this resilience can be severely reduced by human impacts. Assessing the characteristics of SFs and their ecological integrity (EI) is essential to evaluating their role for conservation, restoration, and provisioning of ecosystem services. In this study, we aim to propose a concept and indicators that allow the assessment and classification of the EI of SFs. To this end, we review the literature to assess how EI has been addressed in different ecosystems and which indicators of EI are most commonly used for tropical forests. Building upon this knowledge we propose a modification of the concept of EI to embrace SFs and suggest indicators of EI that can be applied to different successional stages or stand ages. Additionally, we relate these indicators to ecosystem service provision in order to support the practical application of the theory. EI is generally defined as the ability of ecosystems to support and maintain composition, structure and function similar to the reference conditions of an undisturbed ecosystem. This definition does not consider the temporal dynamics of recovering ecosystems, such as SFs. Therefore, we suggest incorporation of an optimal successional trajectory as a reference in addition to the old-growth forest reference. The optimal successional trajectory represents the maximum EI that can be attained at each successional stage in a given region and enables the evaluation of EI at any given age class. We further suggest a list of indicators, the main ones being: compositional indicators (species diversity/richness and indicator species); structural indicators (basal area, heterogeneity of basal area and canopy cover); function indicators (tree growth and mortality); and landscape proxies (landscape heterogeneity, landscape connectivity). Finally, we discuss how this approach can assist in defining the value of SF patches to provide ecosystem services, restore forests and contribute to ecosystem conservation.
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Affiliation(s)
- Milena F Rosenfield
- Instituto Nacional de Pesquisas da Amazônia (INPA), Av. André Araújo, 2936, Manaus, AM, 69083-000, Brazil
| | - Catarina C Jakovac
- Forest Ecology and Forest Management Group, Wageningen University & Research, PO Box 47, 6700 AA, Wageningen, The Netherlands
- Centro de Ciências Agrárias, Universidade Federal de Santa Catarina (UFSC), Rod. Admar Gonzaga, 1346, Itacorubi, Florianópolis, SC, 88034-000, Brazil
| | - Daniel L M Vieira
- Embrapa Recursos Genéticos e Biotecnologia, Empresa Brasileira de Pesquisa Agropecuária (Embrapa), Av. W5 Norte (final), Brasília, DF, 70770917, Brazil
| | - Lourens Poorter
- Forest Ecology and Forest Management Group, Wageningen University & Research, PO Box 47, 6700 AA, Wageningen, The Netherlands
| | - Pedro H S Brancalion
- Departamento de Ciências Florestais, Escola Superior de Agricultura Luiz de Queiroz (ESALQ), Universidade de São Paulo (USP), Av. Pádua Dias, 11, Piracicaba, SP, 13418-900, Brazil
| | - Ima C G Vieira
- Coordenação de Botânica, Museu Paraense Emílio Goeldi, Av. Magalhães Barata, 376, Belém, PA, 66040-170, Brazil
| | - Danilo R A de Almeida
- Departamento de Ciências Florestais, Escola Superior de Agricultura Luiz de Queiroz (ESALQ), Universidade de São Paulo (USP), Av. Pádua Dias, 11, Piracicaba, SP, 13418-900, Brazil
| | - Paulo Massoca
- Center for the Analysis of Social-Ecological Landscapes (CASEL), Indiana University, Student Building 331, 701 E. Kirkwood Avenue, Bloomington, IN, 47405, USA
| | - Juliana Schietti
- Departamento de Biologia, Instituto de Ciências Biológicas, Universidade Federal do Amazonas (UFAM), Av. General Rodrigo Octavio Jordão Ramos, 1200, Coroado I, Manaus, AM, 69067-005, Brazil
| | - Ana Luisa M Albernaz
- Coordenação de Ciências da Terra e Ecologia, Museu Paraense Emílio Goeldi, Av. Magalhães Barata, 376, Belém, PA, 66040-170, Brazil
| | - Marciel J Ferreira
- Departamento de Ciências Florestais, Universidade Federal do Amazonas (UFAM), Av. General Rodrigo Octávio Jordão Ramos, 3000, Manaus, AM, 69080-900, Brazil
| | - Rita C G Mesquita
- Instituto Nacional de Pesquisas da Amazônia (INPA), Av. André Araújo, 2936, Manaus, AM, 69083-000, Brazil
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2
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Novick K, Jo I, D'Orangeville L, Benson M, Au TF, Barnes M, Denham S, Fei S, Heilman K, Hwang T, Keyser T, Maxwell J, Miniat C, McLachlan J, Pederson N, Wang L, Wood JD, Phillips RP. The Drought Response of Eastern US Oaks in the Context of Their Declining Abundance. Bioscience 2022. [DOI: 10.1093/biosci/biab135] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
The oak (Quercus) species of eastern North America are declining in abundance, threatening the many socioecological benefits they provide. We discuss the mechanisms responsible for their loss, many of which are rooted in the prevailing view that oaks are drought tolerant. We then synthesize previously published data to comprehensively review the drought response strategies of eastern US oaks, concluding that whether or not eastern oaks are drought tolerant depends firmly on the metric of success. Although the anisohydric strategy of oaks sometimes confers a gas exchange and growth advantage, it exposes oaks to damaging hydraulic failure, such that oaks are just as or more likely to perish during drought than neighboring species. Consequently, drought frequency is not a strong predictor of historic patterns of oak abundance, although long-term climate and fire frequency are strongly correlated with declines in oak dominance. The oaks’ ability to survive drought may become increasingly difficult in a drier future.
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3
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Asbjornsen H, McIntire CD, Vadeboncoeur MA, Jennings KA, Coble AP, Berry ZC. Sensitivity and threshold dynamics of Pinus strobus and Quercus spp. in response to experimental and naturally occurring severe droughts. TREE PHYSIOLOGY 2021; 41:1819-1835. [PMID: 33904579 DOI: 10.1093/treephys/tpab056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 03/30/2021] [Indexed: 06/12/2023]
Abstract
Increased drought frequency and severity are a pervasive global threat, yet the capacity of mesic temperate forests to maintain resilience in response to drought remains poorly understood. We deployed a throughfall removal experiment to simulate a once in a century drought in New Hampshire, USA, which coupled with the region-wide 2016 drought, intensified moisture stress beyond that experienced in the lifetimes of our study trees. To assess the sensitivity and threshold dynamics of two dominant northeastern tree genera (Quercus and Pinus), we monitored sap flux density (Js), leaf water potential and gas exchange, growth and intrinsic water-use efficiency (iWUE) for one pretreatment year (2015) and two treatment years (2016-17). Results showed that Js in pine (Pinus strobus L.) declined abruptly at a soil moisture threshold of 0.15 m3 m-3, whereas oak's (Quercus rubra L. and Quercus velutina Lam.) threshold was 0.11 m3 m-3-a finding consistent with pine's more isohydric strategy. Nevertheless, once oaks' moisture threshold was surpassed, Js declined abruptly, suggesting that while oaks are well adapted to moderate drought, they are highly susceptible to extreme drought. The radial growth reduction in response to the 2016 drought was more than twice as great for pine as for oaks (50 vs 18%, respectively). Despite relatively high precipitation in 2017, the oaks' growth continued to decline (low recovery), whereas pine showed neutral (treatment) or improved (control) growth. The iWUE increased in 2016 for both treatment and control pines, but only in treatment oaks. Notably, pines exhibited a significant linear relationship between iWUE and precipitation across years, whereas the oaks only showed a response during the driest conditions, further underscoring the different sensitivity thresholds for these species. Our results provide new insights into how interactions between temperate forest tree species' contrasting physiologies and soil moisture thresholds influence their responses and resilience to extreme drought.
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Affiliation(s)
- Heidi Asbjornsen
- Department of Natural Resources and the Environment, University of New Hampshire, 56 College Rd, Durham, NH 03824, USA
- Earth Systems Research Center, University of New Hampshire, 8 College Rd, Durham, NH 03824, USA
| | - Cameron D McIntire
- Department of Natural Resources and the Environment, University of New Hampshire, 56 College Rd, Durham, NH 03824, USA
- State and Private Forestry, USDA Forest Service, 271 Mast Road, Durham, NH 03824, USA
| | - Matthew A Vadeboncoeur
- Earth Systems Research Center, University of New Hampshire, 8 College Rd, Durham, NH 03824, USA
| | - Katie A Jennings
- Department of Natural Resources and the Environment, University of New Hampshire, 56 College Rd, Durham, NH 03824, USA
- Earth Systems Research Center, University of New Hampshire, 8 College Rd, Durham, NH 03824, USA
| | - Adam P Coble
- Department of Natural Resources and the Environment, University of New Hampshire, 56 College Rd, Durham, NH 03824, USA
- Private Forests Division, Oregon Department of Forestry, 2600 State St, Salem, OR 97310, USA
| | - Z Carter Berry
- Department of Natural Resources and the Environment, University of New Hampshire, 56 College Rd, Durham, NH 03824, USA
- Schmid College of Science and Technology, Chapman University, Orange, CA 92866, USA
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4
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Hollunder RK, Mariotte P, Carrijo TT, Holmgren M, Luber J, Stein-Soares B, Guidoni-Martins KG, Ferreira-Santos K, Scarano FR, Garbin ML. Topography and vegetation structure mediate drought impacts on the understory of the South American Atlantic Forest. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 766:144234. [PMID: 33418256 DOI: 10.1016/j.scitotenv.2020.144234] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/20/2020] [Accepted: 11/23/2020] [Indexed: 06/12/2023]
Abstract
Droughts have increased in frequency, duration, and severity across most of the tropics but their effect on forest communities remain not fully understood. Here we assessed the effects of a severe El Niño-induced drought event on dominant and low abundance understory plant species and the consequent impacts on ecosystem functions in the South American Atlantic Forest. We established 20 permanent plots with contrasting vegetation structure and topography. In each plot, we measured the stem diameter at breast height (DBH) of every understory woody plant (i.e. 1 to 10 cm stem diameter) before and after a severe 4-year drought event to calculate relative growth and mortality rates after drought. Litter biomass, litter nutrient content and soil nutrients, as well as tree canopy cover, were also quantified. High stem density reduced survival to drought for both dominant and low abundance understory woody species. The growth rate of dominant and low abundance species was lower on steeper slopes during the drought. Dominant species were the main contributor of litter biomass production whereas low abundance species were important drivers of litter quality. Overall, our findings suggest that habitats with low tree density and larger trees on flat areas, such as in valleys, can act as refuges for understory plant species during drought periods. These habitats are resource-rich, providing nutrients and water during unfavorable drought periods and might improve forest resilience to climate change in the long term.
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Affiliation(s)
- Renan Köpp Hollunder
- Universidade Federal do Rio de Janeiro, Programa de Pós-graduação em Ecologia, IB, CCS, Ilha do Fundão, 21941-970 Rio de Janeiro, RJ, Brazil
| | - Pierre Mariotte
- Grazing Systems, Agroscope, Route de Duillier 50, 1260 Nyon, Switzerland
| | - Tatiana Tavares Carrijo
- Universidade Federal do Espírito Santo, Departamento de Biologia, Centro de Ciências Exatas, Naturais e da Saúde, Alto Universitário, Guararema, 29.500-000 Alegre, ES, Brazil
| | - Milena Holmgren
- Department of Environmental Sciences, Wageningen University, Droevendaalsesteeg 3a, 6708PB Wageningen, the Netherlands
| | - Jaquelini Luber
- Escola Nacional de Botânica Tropical, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, 22.460-036 Rio de Janeiro, RJ, Brazil
| | - Bethina Stein-Soares
- Universidade Federal do Espírito Santo, Departamento de Biologia, Centro de Ciências Exatas, Naturais e da Saúde, Alto Universitário, Guararema, 29.500-000 Alegre, ES, Brazil
| | | | - Karina Ferreira-Santos
- Universidade Federal do Rio de Janeiro, Programa de Pós-graduação em Ecologia, IB, CCS, Ilha do Fundão, 21941-970 Rio de Janeiro, RJ, Brazil
| | - Fabio Rubio Scarano
- Universidade Federal do Rio de Janeiro, Programa de Pós-graduação em Ecologia, IB, CCS, Ilha do Fundão, 21941-970 Rio de Janeiro, RJ, Brazil
| | - Mário Luís Garbin
- Universidade Federal do Espírito Santo, Departamento de Biologia, Centro de Ciências Exatas, Naturais e da Saúde, Alto Universitário, Guararema, 29.500-000 Alegre, ES, Brazil.
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5
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McNellis BE, Smith AMS, Hudak AT, Strand EK. Tree mortality in western U.S. forests forecasted using forest inventory and Random Forest classification. Ecosphere 2021. [DOI: 10.1002/ecs2.3419] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Brandon E. McNellis
- Department of Forest, Rangeland, and Fire Sciences University of Idaho Moscow Idaho83844USA
| | - Alistair M. S. Smith
- Department of Forest, Rangeland, and Fire Sciences University of Idaho Moscow Idaho83844USA
| | - Andrew T. Hudak
- USDA Forest Service Rocky Mountain Research Station Forestry Sciences Laboratory Moscow Idaho83843USA
| | - Eva K. Strand
- Department of Forest, Rangeland, and Fire Sciences University of Idaho Moscow Idaho83844USA
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6
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Refsland T, Knapp B, Stephan K, Fraterrigo J. Sixty‐five years of fire manipulation reveals climate and fire interact to determine growth rates ofQuercusspp. Ecosphere 2020. [DOI: 10.1002/ecs2.3287] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Tyler Refsland
- Program in Ecology, Evolution and Conservation Biology University of Illinois at Urbana‐Champaign 505 S. Goodwin Avenue Urbana Illinois61801USA
| | - Benjamin Knapp
- School of Natural Resources University of Missouri 1111 W. Rollins Road Columbia Missouri65211USA
| | - Kirsten Stephan
- Division of Forestry and Natural Resources West Virginia University 1145 Evansdale Dr Morgantown West Virginia26506USA
| | - Jennifer Fraterrigo
- Program in Ecology, Evolution and Conservation Biology University of Illinois at Urbana‐Champaign 505 S. Goodwin Avenue Urbana Illinois61801USA
- Department of Natural Resources and Environmental Sciences University of Illinois at Urbana‐Champaign 1102 S. Goodwin Avenue Urbana Illinois61801USA
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7
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National Forest Ecosystem Inventory System of China: Methodology and Applications. FORESTS 2020. [DOI: 10.3390/f11070732] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The technical framework of China’s Forest Ecosystem Inventory System (CFEIS) was recently developed based on ecological indicators assessed continuously in the field at forest ecosystem research stations and China’s Forest Resource Inventory (CNFRI) conducted every 5 years. The CFEIS consists of Field Observations (FOs)of ecological indicators and Distributed Valuations (DVs)of forest ecosystem services. The CFEIS can be used with the CNFRI to observe and monitor the ecological status of forests in China. This paper provides a brief review of the CFEIS by introducing its establishment and summarizing its application coupled with the CNFRI. For the FOs, the principles of the monitoring system layout are provided. The Chinese Forest Ecosystem Research Network (CFERN) was set up, which was the largest nationwide network of forest ecological stations in the world. The facilities and equipment were systematically assembled. The national forestry standards were drawn up for describing and measuring the ecological indicators of forest ecosystems, and these standards were used to specify data collection and transmission. For DVs, a distributed measurement method was created, and an indicator system of evaluation was studied and established, with the CNFRI integrated; a series of evaluation formulas and a package of models were also integrated with the DVs. The CFEIS integrated with the CNFRI estimates forest ecosystem services in China and the ecological benefits derived from the Grain for Green program, and a green national economic accounting system will provide an important case for monitoring and inventorying forest ecosystems at a national scale. The CFEIS can provide important experiences for forest ecosystem inventory systems in China and many other parts of the world.
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8
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El Mokni R, Iamonico D. Nuevas alóctonas en Malvaceae para la flora africana del norte, con notas nomenclaturales. COLLECTANEA BOTANICA 2020. [DOI: 10.3989/collectbot.2020.v39.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Como parte de los estudios en curso sobre las Malvaceae de Túnez, se descubrieron poblaciones de dos especies de Hibiscus (H. rosa-sinensis y H. syriacus) y de Lagunaria patersonia en el norte de Túnez, que representan los primeros registros de la flora nacional y norteafricana. Se describen caracteres morfológicos, así como datos ecológicos y corológicos. Se proporcionan notas nomenclaturales sobre los nombres H. acerifolius (= H. syriacus), H. chinensis (= H. syriacus), H. patersonius (basiónimo de L. Patersonia) y H. rhombifolius (= H. syriacus), incluida la designación de holótipo para H. Chinensis (ilustración de van Braam Houckgeest), y designación de lectótipos para H. Acerifolius (una ilustración de Salisbury), H. Rhombifolius (ilustración de Cavanilles) y H. Patersonius (ilustración de Andrew). También se tratan otros nombres ilegítimos e inválidos (Althaea frutex, H. floridus, Ketmia syrorum, K. Arborea y K. Arborescens).
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Tang X, Guan X, Lu S, Qin F, Liu X, Zhang D. Examining the spatiotemporal change of forest resource carrying capacity of the Yangtze River Economic Belt in China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:21213-21230. [PMID: 32266634 DOI: 10.1007/s11356-020-08408-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 03/12/2020] [Indexed: 06/11/2023]
Abstract
Rapid urbanization and the excessive human harvesting of forests have led to a continuous decline in the carrying capacity of forests in China. As a result, quantitative means of measuring forest resource carrying capacity are greatly needed, with a view to identifying problem areas and their causes and formulating effective response strategies. This paper puts forward a framework and methodology for constructing a forest resource carrying capacity index (FRCCI). To do this, we first calculate a forest ecological security index (FESI), using an evaluation index system. Ideal FESI values are then simulated by introducing a forest ecological location coefficient (FELC), and the FRCCI is obtained as the difference between the ideal FESI and the FESI. The study considers the 1086 counties that compose the Yangtze River Economic Belt in China, using forest and socioeconomic data for 2015. The resulting FRCCI values indicate that the forests of Yunnan province are generally in a state of "no overload," while Sichuan, Guizhou, Chongqing, Hunan, Hubei, Jiangxi, and Zhejiang provinces occupied a state of "critical overload" and Anhui and Jiangsu provinces experienced "general overload." The spatial pattern of the FRCCI in the study region presented significant centralization, with high FRCCI values mainly clustered in areas in the upper reaches of the Yangtze River and low FRCCI values mainly clustered in areas in the midstream and downstream reaches of the River. The study identifies 416 counties identified as forest carrying capacity problem areas (38.31% of the study area); these areas were mainly concentrated in Shanghai and Anhui province. We argue that a number of measures would be helpful in improving FRCCI values, including promoting the forest state index by strengthening reforestation as well as afforestation, reducing the external pressure on forests by means of energy saving and emission reduction strategies, and formulating comprehensive policy measures to promote the carrying capacity of forests in the whole study area and in the problem areas.
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Affiliation(s)
- Xu Tang
- School of Economics, Central South University of Forestry and Technology, No.498, Shaoshan South Road, Changsha, Hunan Province, 410004, China
- School of Economics and Management, Beijing Forestry University, No. 35, Tsinghua East Road, Haidian District, Beijing, 100083, China
| | - Xingliang Guan
- National Academy for Mayors of China, No. 2, Huixin West Street, Chaoyang District, Beijing, 100029, China
| | - Shasha Lu
- School of Economics and Management, Beijing Forestry University, No. 35, Tsinghua East Road, Haidian District, Beijing, 100083, China.
| | - Fan Qin
- School of Economics and Management, Beijing Forestry University, No. 35, Tsinghua East Road, Haidian District, Beijing, 100083, China
| | - Xu Liu
- School of Economics and Management, Beijing Forestry University, No. 35, Tsinghua East Road, Haidian District, Beijing, 100083, China
| | - Dahong Zhang
- School of Economics and Management, Beijing Forestry University, No. 35, Tsinghua East Road, Haidian District, Beijing, 100083, China.
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10
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Margalef-Marrase J, Pérez-Navarro MÁ, Lloret F. Relationship between heatwave-induced forest die-off and climatic suitability in multiple tree species. GLOBAL CHANGE BIOLOGY 2020; 26:3134-3146. [PMID: 32064733 DOI: 10.1111/gcb.15042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 01/20/2020] [Accepted: 02/02/2020] [Indexed: 06/10/2023]
Abstract
In recent decades, many forest die-off events have been reported in relation to climate-change-induced episodes, such as droughts and heat waves. To understand how these extreme climatic events induce forest die-off, it is important to find a tool to standardize the climatic conditions experienced by different populations during a specific climatic event, taking into account the historic climatic conditions of the site where these populations live (bioclimatic niche). In this study, we used estimates of climatic suitability calculated from species distribution models (SDMs) for such purpose. We studied forest die-off across France during the 2003 heatwave that affected Western Europe, using 2,943 forest inventory plots dominated by 14 single tree species. Die-off severity was estimated by Normalized Difference Vegetation Index (NDVI) loss using Moderate-resolution Imaging Spectroradiometer remote sensor imagery. Climatic suitability at the local level during the historical 1979-2002 period (HCS), the episode time (2003; ECS) and suitability deviance during the historical period (HCS-SD) were calculated for each species by means of boosted regression tree models using the CHELSA climate database and occurrences extracted from European forest inventories. Low HCS-SD and high mean annual temperature explained the overall regional pattern of vulnerability to die-off across different monospecific forests. The combination of high historical and low episode climatic suitability also contributed significantly to overall forest die-off. Furthermore, we observed different species-specific relationships between die-off vulnerability and climatic suitability: Sub-Mediterranean and Mediterranean species tended to be vulnerable in historically more suitable localities (high HCS), whereas Euro-Siberian species presented greater vulnerability when the hot drought episode was more intense. We demonstrated that at regional scale, past climatic legacy plays an important role in explaining NDVI loss during the episode. Moreover, we demonstrated that SDMs-derived indexes, such as HCS, ECS and HCS-SD, could constitute a tool for standardizing the ways that populations and species experience climatic variability across time and space.
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Affiliation(s)
| | | | - Francisco Lloret
- CREAF, Cerdanyola del Vallès, Spain
- Unitat d'Ecologia, Univ. Autònoma Barcelona, Cerdanyola del Vallès, Spain
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11
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Critical Analysis of the Value of Drought Information and Impacts on Land Management and Public Health. WATER 2020. [DOI: 10.3390/w12041064] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This paper reviews previous efforts to assign monetary value to climatic or meteorological information, such as public information on drought, climate, early warning systems, and weather forecast information. Methods and tools that have been explored to examine the benefits of climatic and meteorological information include the avoided cost, contingent valuation, choice experiments, benefit transfer, and descriptive approaches using surveys. The second part of this paper discusses specific considerations related to valuing drought information for public health and the Bureau of Land Management. We found a multitude of connections between drought and the land management and health sectors in the literature. The majority of the papers that we summarized only report biophysical change, because the economic losses of drought are not available. Only a few papers reported economic loss associated with drought. To determine the value of drought information, we need to know more about the role it plays in decision making and what sources of drought information are used in different sectors. This inventory of methods and impacts highlights opportunities for further research in valuing drought information in land management and public health.
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12
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Ony MA, Nowicki M, Boggess SL, Klingeman WE, Zobel JM, Trigiano RN, Hadziabdic D. Habitat fragmentation influences genetic diversity and differentiation: Fine-scale population structure of Cercis canadensis (eastern redbud). Ecol Evol 2020; 10:3655-3670. [PMID: 32313625 PMCID: PMC7160182 DOI: 10.1002/ece3.6141] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 01/31/2020] [Accepted: 02/05/2020] [Indexed: 02/05/2023] Open
Abstract
Forest fragmentation may negatively affect plants through reduced genetic diversity and increased population structure due to habitat isolation, decreased population size, and disturbance of pollen-seed dispersal mechanisms. However, in the case of tree species, effective pollen-seed dispersal, mating system, and ecological dynamics may help the species overcome the negative effect of forest fragmentation. A fine-scale population genetics study can shed light on the postfragmentation genetic diversity and structure of a species. Here, we present the genetic diversity and population structure of Cercis canadensis L. (eastern redbud) wild populations on a fine scale within fragmented areas centered around the borders of Georgia-Tennessee, USA. We hypothesized high genetic diversity among the collections of C. canadensis distributed across smaller geographical ranges. Fifteen microsatellite loci were used to genotype 172 individuals from 18 unmanaged and naturally occurring collection sites. Our results indicated presence of population structure, overall high genetic diversity (H E = 0.63, H O = 0.34), and moderate genetic differentiation (F ST = 0.14) among the collection sites. Two major genetic clusters within the smaller geographical distribution were revealed by STRUCTURE. Our data suggest that native C. canadensis populations in the fragmented area around the Georgia-Tennessee border were able to maintain high levels of genetic diversity, despite the presence of considerable spatial genetic structure. As habitat isolation may negatively affect gene flow of outcrossing species across time, consequences of habitat fragmentation should be regularly monitored for this and other forest species. This study also has important implications for habitat management efforts and future breeding programs.
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Affiliation(s)
- Meher A. Ony
- Department of Entomology and Plant PathologyUniversity of TennesseeKnoxvilleTNUSA
| | - Marcin Nowicki
- Department of Entomology and Plant PathologyUniversity of TennesseeKnoxvilleTNUSA
| | - Sarah L. Boggess
- Department of Entomology and Plant PathologyUniversity of TennesseeKnoxvilleTNUSA
| | | | - John M. Zobel
- Department of Forest ResourcesUniversity of MinnesotaSt. PaulMNUSA
| | - Robert N. Trigiano
- Department of Entomology and Plant PathologyUniversity of TennesseeKnoxvilleTNUSA
| | - Denita Hadziabdic
- Department of Entomology and Plant PathologyUniversity of TennesseeKnoxvilleTNUSA
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Lu S, Tang X, Guan X, Qin F, Liu X, Zhang D. The assessment of forest ecological security and its determining indicators: A case study of the Yangtze River Economic Belt in China. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 258:110048. [PMID: 31929076 DOI: 10.1016/j.jenvman.2019.110048] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 12/27/2019] [Accepted: 12/27/2019] [Indexed: 06/10/2023]
Abstract
This study put forward an evaluation index system for measuring forest ecological security index (FESI). Taking the 1086 counties located in the Yangtze River Economic Belt as a case study, we investigated the change and its spatial pattern of FESI, as well as the determining indicators (both natural and socio-economic), with the support of Arcmap and GeoDA software. The average FESI value of the study counties in 2010 and 2015 was found to be 0.4226 and 0.4990, increased by 18.08%. Spatially, an evident spatial gradient change was identified, with FESI values in the upstream areas of the Yangtze River being higher than those in midstream areas, and the values of midstream areas in turn being higher than those in downstream areas. The eight tributary basins within the economic belt witnessed significantly different FESI values. Based on the results of this evaluation of FESI and its sub-evaluation indexes, we identified 46.04% of the total counties as constituting "problem areas". These problem areas were mainly concentrated in Shanghai, Jiangsu and Anhui provinces, followed by counties around Dongting Lake, Poyang Lake and in Sichuan province. A regression analysis was conducted in order to identify the determining indicators behind forest ecological security, with results indicating that the ratio of secondary industry, the urbanization rate, the per capita financial institution loan balance, accumulated temperature and wind speed all negatively impacted on FESI values, while population structure, soil organic matter and rainfall were revealed to play a positive role; all of these indicators were highly significant. Given these findings, we also set out a series of policy measures intended to promote the sustainable forest development of the study region. These include the vigorous development of tertiary industry and moves to reduce the proportion of the secondary industry in the national economy, the development of a circular economy, slowing the pace of urbanization, and continued increases in forestry investment in central cities - particularly in problem areas.
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Affiliation(s)
- Shasha Lu
- School of Economics and Management, Beijing Forestry University, No.35, Tsinghua East Road, Haidian District, Beijing, 100083, China
| | - Xu Tang
- School of Economics and Management, Beijing Forestry University, No.35, Tsinghua East Road, Haidian District, Beijing, 100083, China.
| | - Xingliang Guan
- National Academy for Mayors of China, No.2, Huixin West Street, Chaoyang District, Beijing, 100029, China
| | - Fan Qin
- School of Economics and Management, Beijing Forestry University, No.35, Tsinghua East Road, Haidian District, Beijing, 100083, China
| | - Xu Liu
- School of Economics and Management, Beijing Forestry University, No.35, Tsinghua East Road, Haidian District, Beijing, 100083, China
| | - Dahong Zhang
- School of Economics and Management, Beijing Forestry University, No.35, Tsinghua East Road, Haidian District, Beijing, 100083, China.
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14
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Density-dependent processes fluctuate over 50 years in an ecotone forest. Oecologia 2019; 191:909-918. [DOI: 10.1007/s00442-019-04534-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 10/10/2019] [Indexed: 11/27/2022]
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15
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Unsupervised Clustering of Forest Response to Drought Stress in Zululand Region, South Africa. FORESTS 2019. [DOI: 10.3390/f10070531] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Drought limits the production of plantation forests, notably in the drought-prone Zululand region of South Africa. During the last 40 years, the country has faced a series of severe droughts, however that of 2015 stands out as the most extreme and prolonged. The 2015 drought impaired forest productivity and led to widespread tree mortality in this region, but the identification of tree response to drought stress remains uncertain because of its spatial variability. To address this problem, a method that can capture drought patterns and identify trees with similar reactions to drought stress is desired. This could improve the accuracy of detecting trees suffering from drought stress which is key for forest management planning. In this study, we aimed to evaluate the utility of unsupervised mapping approaches in compartments of Eucalyptus trees with similar drought characteristics based on the Normalized Difference Water Index (NDWI) and to demonstrate the value of cloud-based Google Earth Engine (GEE) resources for rapid landscape drought monitoring. Our results showed that calculating distances between pixels using three different matrices (Random Forest (RF) proximity, Euclidean and Manhattan) can accurately detect similarities within a dataset. The RF proximity matrix produced the best measures, which were clustered using Wards hierarchical clustering to detect drought with the highest overall accuracy of 87.7%, followed by Manhattan (85.9%) and Euclidean similarity measures (79.9%), with user and producer results between 84.2% to 91.2%, 42.8% to 98.2% and 37.2% to 94.7%, respectively. These results confirm the value of the RF proximity matrix and underscore the capability of automatic unsupervised mapping approaches for monitoring drought stress in tree plantations, as well as the value of using GEE for providing cost effective datasets to resource stricken countries.
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16
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Forest type and height are important in shaping the altitudinal change of radial growth response to climate change. Sci Rep 2019; 9:1336. [PMID: 30718624 PMCID: PMC6362071 DOI: 10.1038/s41598-018-37823-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 12/13/2018] [Indexed: 11/12/2022] Open
Abstract
Tree radial growth is widely found to respond differently to climate change across altitudinal gradients, but the relative roles of biotic factors (e.g. forest type, height and density) vs. climate gradient remain unclear. We sampled tree rings from 15 plots along a large altitudinal gradient in northeast China, and examined how climate gradient, forest type, height, tree size and density affect: (1) temporal growth variability [mean sensitivity (MS) and standard deviation (SD) of the chronologies], and (2) the relationship of ring width indices (RWI) with historical climate. We used BIC based model selection and variable importance to explore the major drivers of their altitudinal patterns. The results showed that: both growth variability and RWI-climate relationships changed significantly with altitude. Forest height was the most important predictor for altitudinal changes of MS and SD. For RWI-climate relationships, forest type was more important than climate gradient, while height and stem density were weak but necessary predictors. We showed that the altitudinal difference in growth response to climate change cannot be explained by climate gradient alone, and highlight the necessity to examine the influence of biotic factors (which covary with climate across geographic gradient) to better understand forest response to climate change.
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17
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Patterson A, Flores-Rentería L, Whipple A, Whitham T, Gehring C. Common garden experiments disentangle plant genetic and environmental contributions to ectomycorrhizal fungal community structure. THE NEW PHYTOLOGIST 2019; 221:493-502. [PMID: 30009496 DOI: 10.1111/nph.15352] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 06/16/2018] [Indexed: 05/16/2023]
Abstract
The interactions among climate change, plant genetic variation and fungal mutualists are poorly understood, but probably important to plant survival under drought. We examined these interactions by studying the ectomycorrhizal fungal (EMF) communities of pinyon pine seedlings (Pinus edulis) planted in a wildland ecosystem experiencing two decades of climate change-related drought. We established a common garden containing P. edulis seedlings of known maternal lineages (drought tolerant, DT; drought intolerant, DI), manipulated soil moisture and measured EMF community structure and seedling growth. Three findings emerged: EMF community composition differed at the phylum level between DT and DI seedlings, and diversity was two-fold greater in DT than in DI seedlings. EMF communities of DT seedlings did not shift with water treatment and were dominated by an ascomycete, Geopora sp. By contrast, DI seedlings shifted to basidiomycete dominance with increased moisture, demonstrating a lineage by environment interaction. DT seedlings grew larger than DI seedlings in high (28%) and low (50%) watering treatments. These results show that inherited plant traits strongly influence microbial communities, interacting with drought to affect seedling performance. These interactions and their potential feedback effects may influence the success of trees, such as P. edulis, in future climates.
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Affiliation(s)
- Adair Patterson
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011-5640, USA
| | - Lluvia Flores-Rentería
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011-5640, USA
- Department of Biology, San Diego State University, San Diego, CA, 92182, USA
| | - Amy Whipple
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011-5640, USA
- Merriam-Powell Center for Environmental Research, Northern Arizona University, Flagstaff, AZ, 86011-5640, USA
| | - Thomas Whitham
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011-5640, USA
- Merriam-Powell Center for Environmental Research, Northern Arizona University, Flagstaff, AZ, 86011-5640, USA
| | - Catherine Gehring
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011-5640, USA
- Merriam-Powell Center for Environmental Research, Northern Arizona University, Flagstaff, AZ, 86011-5640, USA
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18
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Hagger V, Dwyer J, Shoo L, Wilson K. Use of seasonal forecasting to manage weather risk in ecological restoration. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2018; 28:1797-1807. [PMID: 30024642 DOI: 10.1002/eap.1769] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 04/30/2018] [Accepted: 05/15/2018] [Indexed: 06/08/2023]
Abstract
Ecological restoration has widely variable outcomes from successes to partial or complete failures, and there are diverse perspectives on the factors that influence the likelihood of success. However, not much is known about how these factors are perceived, and whether people's perceptions match realities. We surveyed 307 people involved in the restoration of native vegetation across Australia to identify their perceptions on the factors influencing the success of restoration projects. We found that weather (particularly drought and flooding) has realized impacts on the success of restoration projects, but is not perceived to be an important risk when planning new projects. This highlights the need for better recognition and management of weather risk in restoration and a potential role of seasonal forecasting. We used restoration case studies across Australia to assess the ability of seasonal forecasts provided by the Predictive Ocean Atmosphere Model for Australia, version M24 (POAMA-2) to detect unfavorable weather with sufficient skill and lead time to be useful for restoration projects. We found that rainfall and temperature variables in POAMA-2 predicted 88% of the weather issues encountered in restoration case studies apart from strong winds and cyclones. Of those restoration case studies with predictable weather issues, POAMA-2 had the forecast skill to predict the dominant or first-encountered issue in 67% of cases. We explored the challenges associated with uptake of forecast products through consultation with restoration practitioners and developed a prototype forecast product using a local case study. Integrating seasonal forecasting into decision making through (1) identifying risk management strategies during restoration planning, (2) accessing the forecast a month prior to revegetation activities, and (3) adapting decisions if extreme weather is forecasted, is expected to improve the establishment success of restoration.
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Affiliation(s)
- Valerie Hagger
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, 4072, Australia
- Australian Research Council Centre of Excellence for Environmental Decisions, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - John Dwyer
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, 4072, Australia
- CSIRO, Land and Water Flagship, Dutton Park, Queensland, 4102, Australia
| | - Luke Shoo
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, 4072, Australia
- Australian Research Council Centre of Excellence for Environmental Decisions, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Kerrie Wilson
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland, 4072, Australia
- Australian Research Council Centre of Excellence for Environmental Decisions, The University of Queensland, Brisbane, Queensland, 4072, Australia
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19
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Refsland T, Fraterrigo J. Fire increases drought vulnerability of
Quercus alba
juveniles by altering forest microclimate and nitrogen availability. Funct Ecol 2018. [DOI: 10.1111/1365-2435.13193] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tyler Refsland
- Program in Ecology, Evolution and Conservation BiologyUniversity of Illinois Urbana Illinois
| | - Jennifer Fraterrigo
- Program in Ecology, Evolution and Conservation BiologyUniversity of Illinois Urbana Illinois
- Department of Natural Resources and Environmental SciencesUniversity of Illinois Urbana Illinois
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20
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Contribution of Land Surface Temperature (TCI) to Vegetation Health Index: A Comparative Study Using Clear Sky and All-Weather Climate Data Records. REMOTE SENSING 2018. [DOI: 10.3390/rs10091324] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The Vegetation Health Index (VHI) is widely used for monitoring drought using satellite data. VHI depends on vegetation state and thermal stress, respectively assessed via (i) the Vegetation Condition Index (VCI) that usually relies on information from the visible and near infra-red parts of the spectrum (in the form of Normalized Difference Vegetation Index, NDVI); and (ii) the Thermal Condition Index (TCI), based on top of atmosphere thermal infrared (TIR) brightness temperature or on TIR-derived Land Surface Temperature (LST). VHI is then estimated as a weighted average of VCI and TCI. However, the optimum weights of the two components are usually not known and VHI is usually estimated attributing a weight of 0.5 to both. Using a previously developed methodology for the Euro-Mediterranean region, we show that the multi-scalar drought index (SPEI) may be used to obtain optimal weights for VCI and TCI over the area covered by Meteosat satellites that includes Africa, Europe, and part of South America. The procedure is applied using clear-sky Meteosat Climate Data Records (CDRs) and all-sky LST derived by combining satellite and reanalysis data. Results obtained present a coherent spatial distribution of VCI and TCI weights when estimated using clear- and all-sky LST. This study paves the way for the development of a future VHI near-real time operational product for drought monitoring based on information from Meteosat satellites.
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21
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Effects of Growing-Season Drought on Phenology and Productivity in the West Region of Central Hardwood Forests, USA. FORESTS 2018. [DOI: 10.3390/f9070377] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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22
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Lloret F, Kitzberger T. Historical and event-based bioclimatic suitability predicts regional forest vulnerability to compound effects of severe drought and bark beetle infestation. GLOBAL CHANGE BIOLOGY 2018; 24:1952-1964. [PMID: 29316042 DOI: 10.1111/gcb.14039] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 11/30/2017] [Accepted: 12/13/2017] [Indexed: 06/07/2023]
Abstract
Vulnerability to climate change, and particularly to climate extreme events, is expected to vary across species ranges. Thus, we need tools to standardize the variability in regional climatic legacy and extreme climate across populations and species. Extreme climate events (e.g., droughts) can erode populations close to the limits of species' climatic tolerance. Populations in climatic-core locations may also become vulnerable because they have developed a greater demand for resources (i.e., water) that cannot be enough satisfied during the periods of scarcity. These mechanisms can become exacerbated in tree populations when combined with antagonistic biotic interactions, such as insect infestation. We used climatic suitability indices derived from Species Distribution Models (SDMs) to standardize the climatic conditions experienced across Pinus edulis populations in southwestern North America, during a historical period (1972-2000) and during an extreme event (2001-2007), when the compound effect of hot drought and bark beetle infestation caused widespread die-off and mortality. Pinus edulis climatic suitability diminished dramatically during the die-off period, with remarkable variation between years. P. edulis die-off occurred mainly not just in sites that experienced lower climatic suitability during the drought but also where climatic suitability was higher during the historical period. The combined effect of historically high climatic suitability and a marked decrease in the climatic suitability during the drought best explained the range-wide mortality. Lagged effects of climatic suitability loss in previous years and co-occurrence of Juniperus monosperma also explained P. edulis die-off in particular years. Overall, the study shows that past climatic legacy, likely determining acclimation, together with competitive interactions plays a major role in responses to extreme drought. It also provides a new approach to standardize the magnitude of climatic variability across populations using SDMs, improving our capacity to predict population's or species' vulnerability to climatic change.
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Affiliation(s)
- Francisco Lloret
- CREAF Cerdanyola del Vallès, Bellaterra, Spain
- Univ Autònoma Barcelona, Cerdanyola del Vallès, Spain
| | - Thomas Kitzberger
- Laboratorio Ecotono, INIBIOMA-CONICET, Universidad Nacional del Comahue, Bariloche, Argentina
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23
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Swanteson‐Franz RJ, Krofcheck DJ, Hurteau MD. Quantifying forest carbon dynamics as a function of tree species composition and management under projected climate. Ecosphere 2018. [DOI: 10.1002/ecs2.2191] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Affiliation(s)
| | - Daniel J. Krofcheck
- Department of Biology University of New Mexico MSC03 2020 Albuquerque New Mexico 87131 USA
| | - Matthew D. Hurteau
- Department of Biology University of New Mexico MSC03 2020 Albuquerque New Mexico 87131 USA
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24
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Ibáñez I, Zak DR, Burton AJ, Pregitzer KS. Anthropogenic nitrogen deposition ameliorates the decline in tree growth caused by a drier climate. Ecology 2018; 99:411-420. [DOI: 10.1002/ecy.2095] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 08/01/2017] [Accepted: 11/08/2017] [Indexed: 11/12/2022]
Affiliation(s)
- Inés Ibáñez
- Department of Ecology and Evolutionary Biology School for Environment and Sustainability University of Michigan Ann Arbor Michigan 48109 USA
| | - Donald R. Zak
- Department of Ecology and Evolutionary Biology School for Environment and Sustainability University of Michigan Ann Arbor Michigan 48109 USA
| | - Andrew J. Burton
- School of Forest Resources and Environmental Science Michigan Technological University Houghton Michigan 49937 USA
| | - Kurt S. Pregitzer
- College of Natural Resources University of Idaho Moscow Idaho 83844 USA
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25
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26
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Williams AP, Cook BI, Smerdon JE, Bishop DA, Seager R, Mankin JS. The 2016 southeastern US drought: an extreme departure from centennial wetting and cooling. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2017; 122:10888-10905. [PMID: 29780677 PMCID: PMC5956230 DOI: 10.1002/2017jd027523] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The fall 2016 drought in the southeastern United States (SE US) appeared exceptional based on its widespread impacts, but the current monitoring framework that only extends from 1979-present does not readily facilitate evaluation of soil-moisture anomalies in a centennial context. A new method to extend monthly gridded soil-moisture estimates back to 1895 is developed, indicating that since 1895, October-November 2016 soil moisture (0-200 cm) in the SE US was likely the second lowest on record, behind 1954. This severe drought developed rapidly and was brought on by low September-November precipitation and record-high September-November daily maximum temperatures (Tmax). Record Tmax drove record-high atmospheric moisture demand, accounting for 28% of the October-November 2016 soil-moisture anomaly. Drought and heat in fall 2016 contrasted with 20th-century wetting and cooling in the region, but resembled conditions more common from 1895-1956. Dynamically, the exceptional drying in fall 2016 was driven by anomalous ridging over the central United States that reduced south-southwesterly moisture transports into the SE US by approximately 75%. These circulation anomalies were likely promoted by a moderate La Niña and warmth in the tropical Atlantic, but these processes accounted for very little of the SE US drying in fall 2016, implying a large role for internal atmospheric variability. The extended analysis back to 1895 indicates that SE US droughts as strong as the 2016 event are more likely than indicated from a shorter 60-year perspective, and continued multi-decadal swings in precipitation may combine with future warming to further enhance the likelihood of such events.
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Affiliation(s)
- A. Park Williams
- Lamont-Doherty Earth Observatory of Columbia University; Palisades, NY 10964, USA
| | - Benjamin I. Cook
- NASA Goddard Institute for Space Studies; New York, NY 10025, USA
| | - Jason E. Smerdon
- Lamont-Doherty Earth Observatory of Columbia University; Palisades, NY 10964, USA
| | - Daniel A. Bishop
- Lamont-Doherty Earth Observatory of Columbia University; Palisades, NY 10964, USA
- Department of Earth and Environmental Sciences, Columbia University; New York, NY 10025, USA
| | - Richard Seager
- Lamont-Doherty Earth Observatory of Columbia University; Palisades, NY 10964, USA
| | - Justin S. Mankin
- Lamont-Doherty Earth Observatory of Columbia University; Palisades, NY 10964, USA
- NASA Goddard Institute for Space Studies; New York, NY 10025, USA
- Department of Geography, Dartmouth College; Hanover, NH 03755, USA
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27
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Carnwath G, Nelson C. Effects of biotic and abiotic factors on resistance versus resilience of Douglas fir to drought. PLoS One 2017; 12:e0185604. [PMID: 28973008 PMCID: PMC5626460 DOI: 10.1371/journal.pone.0185604] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 09/15/2017] [Indexed: 11/19/2022] Open
Abstract
Significant increases in tree mortality due to drought-induced physiological stress have been documented worldwide. This trend is likely to continue with increased frequency and severity of extreme drought events in the future. Therefore, understanding the factors that influence variability in drought responses among trees will be critical to predicting ecosystem responses to climate change and developing effective management actions. In this study, we used hierarchical mixed-effects models to analyze drought responses of Pseudotsuga menziesii in 20 unmanaged forests stands across a broad range of environmental conditions in northeastern Washington, USA. We aimed to 1) identify the biotic and abiotic attributes most closely associated with the responses of individual trees to drought and 2) quantify the variability in drought responses at different spatial scales. We found that growth rates and competition for resources significantly affected resistance to a severe drought event in 2001: slow-growing trees and trees growing in subordinate canopy positions and/or with more neighbors suffered greater declines in radial growth during the drought event. In contrast, the ability of a tree to return to normal growth when climatic conditions improved (resilience) was unaffected by competition or relative growth rates. Drought responses were significantly influenced by tree age: older trees were more resistant but less resilient than younger trees. Finally, we found differences between resistance and resilience in spatial scale: a significant proportion (approximately 50%) of the variability in drought resistance across the study area was at broad spatial scales (i.e. among different forest types), most likely due to differences in the total amount of precipitation received at different elevations; in contrast, variation in resilience was overwhelmingly (82%) at the level of individual trees within stands and there was no difference in drought resilience among forest types. Our results suggest that for Pseudotsuga menziesii resistance and resilience to drought are driven by different factors and vary at different spatial scales.
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Affiliation(s)
- Gunnar Carnwath
- Department of Ecosystem and Conservation Sciences, W.A. Franke College of Forestry and Conservation, University of Montana, Missoula, Montana, United States of America
| | - Cara Nelson
- Department of Ecosystem and Conservation Sciences, W.A. Franke College of Forestry and Conservation, University of Montana, Missoula, Montana, United States of America
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28
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Paz-Kagan T, Asner GP. Drivers of woody canopy water content responses to drought in a Mediterranean-type ecosystem. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2017; 27:2220-2233. [PMID: 28727205 DOI: 10.1002/eap.1603] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 05/01/2017] [Accepted: 06/20/2017] [Indexed: 06/07/2023]
Abstract
Severe droughts increase physiological stress in woody plant species, which can lead to mortality, fundamentally altering the composition, structure, and biogeography of forests in many regions. Little is known, however, about the factors determining the physiological response of woody plants to drought at landscape scales. Our objective was to understand woody plant species responses to ongoing changes in climate, using remotely sensed canopy water content (CWC) as an indicator of plant physiological and phenological status. We used fused imaging spectroscopy and light detection and ranging from the Carnegie Airborne Observatory to quantify the factors affecting species compositional changes in CWC in a diverse Mediterranean-type ecosystem (Jasper Ridge Biological Preserve, California, USA) between 2013 and 2015. Mapped CWC was spatially variable in both of the observation years, and proved to be most closely tied to species composition and distribution across the landscape. The secondary predictors of CWC were elevation and soil substrate. In contrast, we found that CWC change was much more related to environmental factors than to the species composition. We suggest that the effect of environment on CWC change is mediated through species resistance and resilience to drought. Monitoring CWC change with imaging spectroscopy is a powerful approach to identifying species-level responses to climatic events and long-term change, which may provide support for policy decisions and conservation at large spatial scales.
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Affiliation(s)
- Tarin Paz-Kagan
- Department of Global Ecology, Carnegie Institution for Science, Stanford, California, 94305, USA
| | - Gregory P Asner
- Department of Global Ecology, Carnegie Institution for Science, Stanford, California, 94305, USA
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29
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Monitoring Changes in Water Use Efficiency to Understand Drought Induced Tree Mortality. FORESTS 2017. [DOI: 10.3390/f8100365] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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30
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Tree Species Selection in the Face of Drought Risk—Uncertainty in Forest Planning. FORESTS 2017. [DOI: 10.3390/f8100363] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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31
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Quantifying the synergistic effects of impervious surface and drought on radial tree growth. Urban Ecosyst 2017. [DOI: 10.1007/s11252-017-0699-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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32
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Parolari AJ, Mobley ML, Bacon AR, Katul GG, Richter DD, Porporato A. Boom and bust carbon-nitrogen dynamics during reforestation. Ecol Modell 2017. [DOI: 10.1016/j.ecolmodel.2017.06.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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33
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Evans MEK, Falk DA, Arizpe A, Swetnam TL, Babst F, Holsinger KE. Fusing tree-ring and forest inventory data to infer influences on tree growth. Ecosphere 2017. [DOI: 10.1002/ecs2.1889] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Affiliation(s)
- Margaret E. K. Evans
- Laboratory of Tree Ring Research; University of Arizona; Tucson Arizona 85721 USA
- Department of Ecology & Evolutionary Biology; University of Arizona; Tucson Arizona 85721 USA
| | - Donald A. Falk
- Laboratory of Tree Ring Research; University of Arizona; Tucson Arizona 85721 USA
- School of Natural Resources and the Environment; University of Arizona; Tucson Arizona 85721 USA
| | - Alexis Arizpe
- Laboratory of Tree Ring Research; University of Arizona; Tucson Arizona 85721 USA
| | | | - Flurin Babst
- Dendro Sciences Group; Swiss Federal Research Institute WSL; 8903 Birmensdorf Switzerland
- W. Szafer Institute of Botany; Polish Academy of Sciences; 31-512 Krakow Poland
| | - Kent E. Holsinger
- Department of Ecology & Evolutionary Biology; University of Connecticut Storrs; Storrs Connecticut 06269 USA
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Gleason KE, Bradford JB, Bottero A, D'Amato AW, Fraver S, Palik BJ, Battaglia MA, Iverson L, Kenefic L, Kern CC. Competition amplifies drought stress in forests across broad climatic and compositional gradients. Ecosphere 2017. [DOI: 10.1002/ecs2.1849] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Affiliation(s)
- Kelly E. Gleason
- Southwest Biological Science Center US Geological Survey Flagstaff Arizona 86011 USA
| | - John B. Bradford
- Southwest Biological Science Center US Geological Survey Flagstaff Arizona 86011 USA
| | - Alessandra Bottero
- Department of Forest Resources University of Minnesota Minneapolis Minnesota 55455 USA
| | - Anthony W. D'Amato
- Rubenstein School of Environment and Natural Resources University of Vermont 204E Aiken Center Burlington Vermont 05405 USA
| | - Shawn Fraver
- School of Forest Resources University of Maine 5755 Nutting Hall Orono Maine 04469‐5755 USA
| | - Brian J. Palik
- Northern Research Station USDA Forest Service 1831 Highway 169 E Grand Rapids Minnesota 80526 USA
| | - Michael A. Battaglia
- Rocky Mountain Research Station USDA Forest Service 240 West Prospect Road Fort Collins Colorado 80526 USA
| | - Louis Iverson
- 3 Northern Research Station USDA Forest Service 59 Main Road Delaware Ohio 43015 USA
| | - Laura Kenefic
- Center for Ecosystem Change Northern Research Station USDA Forest Service 686 Government Road Bradley Maine 04411 USA
| | - Christel C. Kern
- Northern Research Station USDA Forest Service 5985 Highway K Rhinelander Wisconsin 54501 USA
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35
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Matyssek R, Kozovits AR, Wieser G, King J, Rennenberg H. Woody-plant ecosystems under climate change and air pollution-response consistencies across zonobiomes? TREE PHYSIOLOGY 2017; 37:706-732. [PMID: 28338970 DOI: 10.1093/treephys/tpx009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 01/22/2017] [Indexed: 06/06/2023]
Abstract
Forests store the largest terrestrial pools of carbon (C), helping to stabilize the global climate system, yet are threatened by climate change (CC) and associated air pollution (AP, highlighting ozone (O3) and nitrogen oxides (NOx)). We adopt the perspective that CC-AP drivers and physiological impacts are universal, resulting in consistent stress responses of forest ecosystems across zonobiomes. Evidence supporting this viewpoint is presented from the literature on ecosystem gross/net primary productivity and water cycling. Responses to CC-AP are compared across evergreen/deciduous foliage types, discussing implications of nutrition and resource turnover at tree and ecosystem scales. The availability of data is extremely uneven across zonobiomes, yet unifying patterns of ecosystem response are discernable. Ecosystem warming results in trade-offs between respiration and biomass production, affecting high elevation forests more than in the lowland tropics and low-elevation temperate zone. Resilience to drought is modulated by tree size and species richness. Elevated O3 tends to counteract stimulation by elevated carbon dioxide (CO2). Biotic stress and genomic structure ultimately determine ecosystem responsiveness. Aggrading early- rather than mature late-successional communities respond to CO2 enhancement, whereas O3 affects North American and Eurasian tree species consistently under free-air fumigation. Insect herbivory is exacerbated by CC-AP in biome-specific ways. Rhizosphere responses reflect similar stand-level nutritional dynamics across zonobiomes, but are modulated by differences in tree-soil nutrient cycling between deciduous and evergreen systems, and natural versus anthropogenic nitrogen (N) oversupply. The hypothesis of consistency of forest responses to interacting CC-AP is supported by currently available data, establishing the precedent for a global network of long-term coordinated research sites across zonobiomes to simultaneously advance both bottom-up (e.g., mechanistic) and top-down (systems-level) understanding. This global, synthetic approach is needed because high biological plasticity and physiographic variation across individual ecosystems currently limit development of predictive models of forest responses to CC-AP. Integrated research on C and nutrient cycling, O3-vegetation interactions and water relations must target mechanisms' ecosystem responsiveness. Worldwide case studies must be subject to biostatistical exploration to elucidate overarching response patterns and synthesize the resulting empirical data through advanced modelling, in order to provide regionally coherent, yet globally integrated information in support of internationally coordinated decision-making and policy development.
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Affiliation(s)
- R Matyssek
- Technische Universität München, TUM School of Life Sciences Weihenstephan, Chair of Ecophysiology of Plants, Hans-Carl-von-Carlowitz-Platz 2, D-85354 Freising, Germany
| | - A R Kozovits
- Universidade Federal de Ouro Preto, Department of Biodiversity, Evolution and Environment, Campus Morro do Cruzeiro, Bauxita, 35.400-000 Ouro Preto, MG, Brazil
| | - G Wieser
- Department of Alpine Timberline Ecophysiology, Federal Office and Research Centre for Forests, Innsbruck, Austria
| | - J King
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC, USA
| | - H Rennenberg
- Chair of Tree Physiology, Institute of Forest Sciences, University of Freiburg, Georges-Koehler-Allee 53/54, D79110 Freiburg, Germany
- King Saud University, PO Box 2454, Riyadh 11451, Saudi Arabia
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36
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Itter MS, Finley AO, D'Amato AW, Foster JR, Bradford JB. Variable effects of climate on forest growth in relation to climate extremes, disturbance, and forest dynamics. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2017; 27:1082-1095. [PMID: 28182303 DOI: 10.1002/eap.1518] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 01/13/2017] [Accepted: 01/19/2017] [Indexed: 06/06/2023]
Abstract
Changes in the frequency, duration, and severity of climate extremes are forecast to occur under global climate change. The impacts of climate extremes on forest productivity and health remain difficult to predict due to potential interactions with disturbance events and forest dynamics-changes in forest stand composition, density, size and age structure over time. Such interactions may lead to non-linear forest growth responses to climate involving thresholds and lag effects. Understanding how forest dynamics influence growth responses to climate is particularly important given stand structure and composition can be modified through management to increase forest resistance and resilience to climate change. To inform such adaptive management, we develop a hierarchical Bayesian state space model in which climate effects on tree growth are allowed to vary over time and in relation to past climate extremes, disturbance events, and forest dynamics. The model is an important step toward integrating disturbance and forest dynamics into predictions of forest growth responses to climate extremes. We apply the model to a dendrochronology data set from forest stands of varying composition, structure, and development stage in northeastern Minnesota that have experienced extreme climate years and forest tent caterpillar defoliation events. Mean forest growth was most sensitive to water balance variables representing climatic water deficit. Forest growth responses to water deficit were partitioned into responses driven by climatic threshold exceedances and interactions with insect defoliation. Forest growth was both resistant and resilient to climate extremes with the majority of forest growth responses occurring after multiple climatic threshold exceedances across seasons and years. Interactions between climate and disturbance were observed in a subset of years with insect defoliation increasing forest growth sensitivity to water availability. Forest growth was particularly sensitive to climate extremes during periods of high stem density following major regeneration events when average inter-tree competition was high. Results suggest the resistance and resilience of forest growth to climate extremes can be increased through management steps such as thinning to reduce competition during early stages of stand development and small-group selection harvests to maintain forest structures characteristic of older, mature stands.
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Affiliation(s)
- Malcolm S Itter
- Department of Forestry, Michigan State University, Natural Resources Building, 480 Wilson Road, East Lansing, Michigan, 48824, USA
- Ecology, Evolutionary Biology and Behavior Program, Michigan State University, Giltner Hall, 293 Farm Lane Road, East Lansing, Michigan, 48824, USA
| | - Andrew O Finley
- Department of Forestry, Michigan State University, Natural Resources Building, 480 Wilson Road, East Lansing, Michigan, 48824, USA
- Department of Geography, Michigan State University, Geography Building, 673 Auditorium Road, East Lansing, Michigan, 48824, USA
| | - Anthony W D'Amato
- Rubenstein School of Environment and Natural Resources, University of Vermont, Aiken Center, 81 Carrigan Drive, Burlington, Vermont, 05405, USA
| | - Jane R Foster
- Department of Forest Resources, University of Minnesota, Green Hall, 1530 Cleveland Avenue North, St. Paul, Minnesota, 55108, USA
| | - John B Bradford
- U.S. Geological Survey, Southwest Biological Science Center, P.O. Box 5614 Building 56, Flagstaff, Arizona, 86011, USA
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37
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Hu H, Wang GG, Bauerle WL, Klos RJ. Drought impact on forest regeneration in the Southeast
USA. Ecosphere 2017. [DOI: 10.1002/ecs2.1772] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Huifeng Hu
- State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing 100093 China
- Department of Forestry and Environmental Conservation Clemson University Clemson South Carolina 29634 USA
| | - G. Geoff Wang
- Department of Forestry and Environmental Conservation Clemson University Clemson South Carolina 29634 USA
| | - William L. Bauerle
- Department of Horticulture and Landscape Architecture Colorado State University Fort Collins Colorado 80523 USA
| | - Ryan J. Klos
- Department of Forestry and Environmental Conservation Clemson University Clemson South Carolina 29634 USA
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38
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Greenwood S, Ruiz-Benito P, Martínez-Vilalta J, Lloret F, Kitzberger T, Allen CD, Fensham R, Laughlin DC, Kattge J, Bönisch G, Kraft NJB, Jump AS. Tree mortality across biomes is promoted by drought intensity, lower wood density and higher specific leaf area. Ecol Lett 2017; 20:539-553. [PMID: 28220612 DOI: 10.1111/ele.12748] [Citation(s) in RCA: 166] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 12/23/2016] [Accepted: 01/16/2017] [Indexed: 12/18/2022]
Abstract
Drought events are increasing globally, and reports of consequent forest mortality are widespread. However, due to a lack of a quantitative global synthesis, it is still not clear whether drought-induced mortality rates differ among global biomes and whether functional traits influence the risk of drought-induced mortality. To address these uncertainties, we performed a global meta-analysis of 58 studies of drought-induced forest mortality. Mortality rates were modelled as a function of drought, temperature, biomes, phylogenetic and functional groups and functional traits. We identified a consistent global-scale response, where mortality increased with drought severity [log mortality (trees trees-1 year-1 ) increased 0.46 (95% CI = 0.2-0.7) with one SPEI unit drought intensity]. We found no significant differences in the magnitude of the response depending on forest biomes or between angiosperms and gymnosperms or evergreen and deciduous tree species. Functional traits explained some of the variation in drought responses between species (i.e. increased from 30 to 37% when wood density and specific leaf area were included). Tree species with denser wood and lower specific leaf area showed lower mortality responses. Our results illustrate the value of functional traits for understanding patterns of drought-induced tree mortality and suggest that mortality could become increasingly widespread in the future.
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Affiliation(s)
- Sarah Greenwood
- Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, Scotland
| | - Paloma Ruiz-Benito
- Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, Scotland.,Forest Ecology and Restoration Group, Life Sciences Department, Universidad de Alcalá, Science Building, Alcalá de Henares, 28805, Madrid, Spain
| | - Jordi Martínez-Vilalta
- CREAF Cerdanyola del Vallès, Barcelona, 08193, Spain.,Universidad Autònoma Barcelona, Cerdanyola del Vallès, Barcelona, 08193, Spain
| | - Francisco Lloret
- CREAF Cerdanyola del Vallès, Barcelona, 08193, Spain.,Universidad Autònoma Barcelona, Cerdanyola del Vallès, Barcelona, 08193, Spain
| | - Thomas Kitzberger
- Laboratorio Ecotono, INIBIOMA, CONICET-Universidad Nacional del Comahue, Bariloche, Río Negro, Argentina
| | - Craig D Allen
- U.S. Geological Survey, Fort Collins Science Center, New Mexico Landscapes Field Station, Los Alamos, New Mexico, 87544, USA
| | - Rod Fensham
- Queensland Herbarium, Environmental Protection Agency, Mt Coot-tha Road, Toowong, Qld, 4066, Australia.,School of Biological Sciences, University of Queensland, St Lucia, Qld, 4072, Australia
| | - Daniel C Laughlin
- Environmental Research Institute and School of Science, University of Waikato, Hamilton, New Zealand
| | - Jens Kattge
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Straße 10, 07745, Jena, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig Deutscher Platz 5e, 04103, Leipzig, Germany
| | - Gerhard Bönisch
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Straße 10, 07745, Jena, Germany
| | - Nathan J B Kraft
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA
| | - Alistair S Jump
- Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, Scotland.,CREAF Cerdanyola del Vallès, Barcelona, 08193, Spain
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39
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Colangelo M, Camarero JJ, Borghetti M, Gazol A, Gentilesca T, Ripullone F. Size Matters a Lot: Drought-Affected Italian Oaks Are Smaller and Show Lower Growth Prior to Tree Death. FRONTIERS IN PLANT SCIENCE 2017; 8:135. [PMID: 28270816 PMCID: PMC5318376 DOI: 10.3389/fpls.2017.00135] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 01/23/2017] [Indexed: 05/10/2023]
Abstract
Hydraulic theory suggests that tall trees are at greater risk of drought-triggered death caused by hydraulic failure than small trees. In addition the drop in growth, observed in several tree species prior to death, is often interpreted as an early-warning signal of impending death. We test these hypotheses by comparing size, growth, and wood-anatomy patterns of living and now-dead trees in two Italian oak forests showing recent mortality episodes. The mortality probability of trees is modeled as a function of recent growth and tree size. Drift-diffusion-jump (DDJ) metrics are used to detect early-warning signals. We found that the tallest trees of the anisohydric Italian oak better survived drought contrary to what was predicted by the theory. Dead trees were characterized by a lower height and radial-growth trend than living trees in both study sites. The growth reduction of now-dead trees started about 10 years prior to their death and after two severe spring droughts during the early 2000s. This critical transition in growth was detected by DDJ metrics in the most affected site. Dead trees were also more sensitive to drought stress in this site indicating different susceptibility to water shortage between trees. Dead trees did not form earlywood vessels with smaller lumen diameter than surviving trees but tended to form wider latewood vessels with a higher percentage of vessel area. Since living and dead trees showed similar competition we did not expect that moderate thinning and a reduction in tree density would increase the short-term survival probability of trees.
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Affiliation(s)
- Michele Colangelo
- School of Agricultural Forest Food and Environmental Sciences, University of BasilicataPotenza, Italy
| | - Jesús J. Camarero
- Pyrenean Institute of Ecology – Consejo Superior de Investigaciones CientíficasZaragoza, Spain
| | - Marco Borghetti
- School of Agricultural Forest Food and Environmental Sciences, University of BasilicataPotenza, Italy
| | - Antonio Gazol
- Pyrenean Institute of Ecology – Consejo Superior de Investigaciones CientíficasZaragoza, Spain
| | - Tiziana Gentilesca
- School of Agricultural Forest Food and Environmental Sciences, University of BasilicataPotenza, Italy
| | - Francesco Ripullone
- School of Agricultural Forest Food and Environmental Sciences, University of BasilicataPotenza, Italy
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40
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O'Brien MJ, Engelbrecht BMJ, Joswig J, Pereyra G, Schuldt B, Jansen S, Kattge J, Landhäusser SM, Levick SR, Preisler Y, Väänänen P, Macinnis-Ng C. A synthesis of tree functional traits related to drought-induced mortality in forests across climatic zones. J Appl Ecol 2017. [DOI: 10.1111/1365-2664.12874] [Citation(s) in RCA: 113] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Michael J. O'Brien
- Estación Experimental de Zonas Áridas; Consejo Superior de Investigaciones Científicas; Carretera de Sacramento s/n E-04120 La Cañada Almería Spain
- Department of Evolutionary Biology and Environmental Studies; University of Zurich; Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Bettina M. J. Engelbrecht
- Department of Plant Ecology; Bayreuth Center for Ecology and Environmental Research; University of Bayreuth; 95440 Bayreuth Germany
- Smithsonian Tropical Research Institute; Apartado 0843-03092 Balboa Ancon Republic of Panama
| | - Julia Joswig
- Max-Plank Institute for Biogeochemistry; Hans-Knöll-Str. 10 07745 Jena Germany
| | - Gabriela Pereyra
- Max-Plank Institute for Biogeochemistry; Hans-Knöll-Str. 10 07745 Jena Germany
| | - Bernhard Schuldt
- Plant Ecology; Albrecht von Haller Institute for Plant Sciences; University of Göttingen; UntereKarspüle 2 37073 Göttingen Germany
| | - Steven Jansen
- Institute of Systematic Botany and Ecology; Ulm University; Albert-Einstein-Allee 11 89081 Ulm Germany
| | - Jens Kattge
- Max-Plank Institute for Biogeochemistry; Hans-Knöll-Str. 10 07745 Jena Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig; Deutscher Platz 5e 04103 Leipzig Germany
| | - Simon M. Landhäusser
- Department of Renewable Resources; University of Alberta; Edmonton AB T6G 2E3 Canada
| | - Shaun R. Levick
- Max-Plank Institute for Biogeochemistry; Hans-Knöll-Str. 10 07745 Jena Germany
| | - Yakir Preisler
- Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture; The Hebrew University of Jerusalem; PO Box 12 Rehovot 76100 Israel
- Department of Earth and Planetary Science; Weizmann Institute of Science; Rehovot Israel
| | - Päivi Väänänen
- Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture; The Hebrew University of Jerusalem; PO Box 12 Rehovot 76100 Israel
| | - Cate Macinnis-Ng
- School of Biological Sciences; University of Auckland; Private Bag 92019 Auckland 1142 New Zealand
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41
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Impact of Water Scarcity on the Fenhe River Basin and Mitigation Strategies. WATER 2017. [DOI: 10.3390/w9010030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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42
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Cavin L, Jump AS. Highest drought sensitivity and lowest resistance to growth suppression are found in the range core of the tree Fagus sylvatica L. not the equatorial range edge. GLOBAL CHANGE BIOLOGY 2017; 23:362-379. [PMID: 27298138 DOI: 10.1111/gcb.13366] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 04/26/2016] [Indexed: 06/06/2023]
Abstract
Biogeographical and ecological theory suggests that species distributions should be driven to higher altitudes and latitudes as global temperatures rise. Such changes occur as growth improves at the poleward edge of a species distribution and declines at the range edge in the opposite or equatorial direction, mirrored by changes in the establishment of new individuals. A substantial body of evidence demonstrates that such processes are underway for a wide variety of species. Case studies from populations at the equatorial range edge of a variety of woody species have led us to understand that widespread growth decline and distributional shifts are underway. However, in apparent contrast, other studies report high productivity and reproduction in some range edge populations. We sought to assess temporal trends in the growth of the widespread European beech tree (Fagus sylvatica) across its latitudinal range. We explored the stability of populations to major drought events and the implications for predicted widespread growth decline at its equatorial range edge. In contrast to expectations, we found greatest sensitivity and low resistance to drought in the core of the species range, whilst dry range edge populations showed particularly high resistance to drought and little evidence of drought-linked growth decline. We hypothesize that this high range edge resistance to drought is driven primarily by local environmental factors that allow relict populations to persist despite regionally unfavourable climate. The persistence of such populations demonstrates that range-edge decline is not ubiquitous and is likely to be driven by declining population density at the landscape scale rather than sudden and widespread range retraction.
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Affiliation(s)
- Liam Cavin
- Department of Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Alistair S Jump
- Department of Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, UK
- CREAF (Centre de Recerca Ecològica i Aplicacions Forestals, Campus de Bellaterra (UAB), Edifici C. 08193, Cerdanyola del Vallès, Spain
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Schlesinger WH, Dietze MC, Jackson RB, Phillips RP, Rhoades CC, Rustad LE, Vose JM. Forest biogeochemistry in response to drought. GLOBAL CHANGE BIOLOGY 2016; 22:2318-2328. [PMID: 26403995 DOI: 10.1111/gcb.13105] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 08/04/2015] [Indexed: 06/05/2023]
Abstract
Trees alter their use and allocation of nutrients in response to drought, and changes in soil nutrient cycling and trace gas flux (N2 O and CH4 ) are observed when experimental drought is imposed on forests. In extreme droughts, trees are increasingly susceptible to attack by pests and pathogens, which can lead to major changes in nutrient flux to the soil. Extreme droughts often lead to more common and more intense forest fires, causing dramatic changes in the nutrient storage and loss from forest ecosystems. Changes in the future manifestation of drought will affect carbon uptake and storage in forests, leading to feedbacks to the Earth's climate system. We must improve the recognition of drought in nature, our ability to manage our forests in the face of drought, and the parameterization of drought in earth system models for improved predictions of carbon uptake and storage in the world's forests.
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Affiliation(s)
| | - Michael C Dietze
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA, 02215, USA
| | - Robert B Jackson
- Department of Earth System Science, Stanford University, Y2E2 Building, 379B, Stanford, CA, 94305, USA
| | - Richard P Phillips
- Department of Biology, Indiana University, 1 E 3rd Street, Bloomington, IN, 47405, USA
| | - Charles C Rhoades
- U.S.D.A., Forest Service, Rocky Mountain Research Station, 240 West Prospect Road, Fort Collins, CO, 80526, USA
| | - Lindsey E Rustad
- U.S.D.A., Forest Service, Northern Research Station, 271 Mast Rd, Durham, NH, 03824, USA
| | - James M Vose
- U.S.D.A., Forest Service, Southern Research Station, NC State University, Campus Box 8008, Raleigh, NC, 27695, USA
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44
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Clark JS, Iverson L, Woodall CW, Allen CD, Bell DM, Bragg DC, D'Amato AW, Davis FW, Hersh MH, Ibanez I, Jackson ST, Matthews S, Pederson N, Peters M, Schwartz MW, Waring KM, Zimmermann NE. The impacts of increasing drought on forest dynamics, structure, and biodiversity in the United States. GLOBAL CHANGE BIOLOGY 2016; 22:2329-2352. [PMID: 26898361 DOI: 10.1111/gcb.13160] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 10/02/2015] [Accepted: 10/05/2015] [Indexed: 06/05/2023]
Abstract
We synthesize insights from current understanding of drought impacts at stand-to-biogeographic scales, including management options, and we identify challenges to be addressed with new research. Large stand-level shifts underway in western forests already are showing the importance of interactions involving drought, insects, and fire. Diebacks, changes in composition and structure, and shifting range limits are widely observed. In the eastern US, the effects of increasing drought are becoming better understood at the level of individual trees, but this knowledge cannot yet be confidently translated to predictions of changing structure and diversity of forest stands. While eastern forests have not experienced the types of changes seen in western forests in recent decades, they too are vulnerable to drought and could experience significant changes with increased severity, frequency, or duration in drought. Throughout the continental United States, the combination of projected large climate-induced shifts in suitable habitat from modeling studies and limited potential for the rapid migration of tree populations suggests that changing tree and forest biogeography could substantially lag habitat shifts already underway. Forest management practices can partially ameliorate drought impacts through reductions in stand density, selection of drought-tolerant species and genotypes, artificial regeneration, and the development of multistructured stands. However, silvicultural treatments also could exacerbate drought impacts unless implemented with careful attention to site and stand characteristics. Gaps in our understanding should motivate new research on the effects of interactions involving climate and other species at the stand scale and how interactions and multiple responses are represented in models. This assessment indicates that, without a stronger empirical basis for drought impacts at the stand scale, more complex models may provide limited guidance.
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Affiliation(s)
- James S Clark
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
| | - Louis Iverson
- Forest Service, Northern Research Station, 359 Main Road, Delaware, OH, 43015, USA
| | | | - Craig D Allen
- U.S. Geological Survey, Fort Collins Science Center, Jemez Mountains Field Station, Los Alamos, NM, 87544, USA
| | - David M Bell
- Forest Service, Pacific Northwest Research Station, Corvallis, OR, 97331, USA
| | - Don C Bragg
- Forest Service, Southern Research Station, Monticello, AR, 71656, USA
| | - Anthony W D'Amato
- Rubenstein School of Environment and Natural Resources, University of Vermont, 04E Aiken Center, 81 Carrigan Dr., Burlington, VT, 05405, USA
| | - Frank W Davis
- Bren School of Environmental Science and Management, University of California, Santa Barbara, CA, 93106, USA
| | - Michelle H Hersh
- Department of Biology, Sarah Lawrence College, New York, NY, 10708, USA
| | - Ines Ibanez
- School of Natural Resources and Environment, University of Michigan, 2546 Dana Building, Ann Arbor, MI, 48109, USA
| | - Stephen T Jackson
- U.S. Geological Survey, Southwest Climate Science Center and Department of Geosciences, University of Arizona, 1064 E. Lowell St., PO Box 210137, Tucson, AZ, 85721, USA
| | - Stephen Matthews
- School of Environment and Natural Resources, Ohio State University, Columbus, OH, 43210, USA
| | | | - Matthew Peters
- Forest Service, Northern Research Station, Delaware, OH, 43015, USA
| | - Mark W Schwartz
- Department of Environmental Science and Policy, UC Davis, Davis, CA, 93106, USA
| | - Kristen M Waring
- School of Forestry, Northern Arizona University, Flagstaff, AZ, 86001, USA
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45
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Billings SA, Boone AS, Stephen FM. Tree-ring δ13C and δ18O, leaf δ13C and wood and leaf N status demonstrate tree growth strategies and predict susceptibility to disturbance. TREE PHYSIOLOGY 2016; 36:576-88. [PMID: 26960389 PMCID: PMC4886288 DOI: 10.1093/treephys/tpw010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 01/27/2016] [Indexed: 05/30/2023]
Abstract
Understanding how tree growth strategies may influence tree susceptibility to disturbance is an important goal, especially given projected increases in diverse ecological disturbances this century. We use growth responses of tree rings to climate, relationships between tree-ring stable isotopic signatures of carbon (δ(13)C) and oxygen (δ(18)O), wood nitrogen concentration [N], and contemporary leaf [N] and δ(13)C values to assess potential historic drivers of tree photosynthesis in dying and apparently healthy co-occurring northern red oak (Quercus rubra L. (Fagaceae)) during a region-wide oak decline event in Arkansas, USA. Bole growth of both healthy and dying trees responded negatively to drought severity (Palmer Drought Severity Index) and temperature; healthy trees exhibited a positive, but small, response to growing season precipitation. Contrary to expectations, tree-ring δ(13)C did not increase with drought severity. A significantly positive relationship between tree-ring δ(13)C and δ(18)O was evident in dying trees (P < 0.05) but not in healthy trees. Healthy trees' wood exhibited lower [N] than that of dying trees throughout most of their lives (P < 0.05), and we observed a significant, positive relationship (P < 0.05) in healthy trees between contemporary leaf δ(13)C and leaf N (by mass), but not in dying trees. Our work provides evidence that for plants in which strong relationships between δ(13)C and δ(18)O are not evident, δ(13)C may be governed by plant N status. The data further imply that historic photosynthesis in healthy trees was linked to N status and, perhaps, C sink strength to a greater extent than in dying trees, in which tree-ring stable isotopes suggest that historic photosynthesis was governed primarily by stomatal regulation. This, in turn, suggests that assessing the relative dominance of photosynthetic capacity vs stomatal regulation as drivers of trees' C accrual may be a feasible means of predicting tree responses to some disturbance events. Our work demonstrates that a dual isotope, tree-ring approach can be integrated with tree N status to begin to unravel a fundamental question in forest ecology: why do some trees die during a disturbance, while other conspecifics with apparently similar access to resources remain healthy?
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Affiliation(s)
- S A Billings
- Department of Ecology and Evolutionary Biology, Kansas Biological Survey, University of Kansas, Lawrence, KS 66047, USA
| | - A S Boone
- Department of Ecology and Evolutionary Biology, Kansas Biological Survey, University of Kansas, Lawrence, KS 66047, USA
| | - F M Stephen
- Department of Entomology, University of Arkansas, Fayetteville, AR 72701, USA
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Meta-analysis reveals that hydraulic traits explain cross-species patterns of drought-induced tree mortality across the globe. Proc Natl Acad Sci U S A 2016; 113:5024-9. [PMID: 27091965 DOI: 10.1073/pnas.1525678113] [Citation(s) in RCA: 325] [Impact Index Per Article: 40.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Drought-induced tree mortality has been observed globally and is expected to increase under climate change scenarios, with large potential consequences for the terrestrial carbon sink. Predicting mortality across species is crucial for assessing the effects of climate extremes on forest community biodiversity, composition, and carbon sequestration. However, the physiological traits associated with elevated risk of mortality in diverse ecosystems remain unknown, although these traits could greatly improve understanding and prediction of tree mortality in forests. We performed a meta-analysis on species' mortality rates across 475 species from 33 studies around the globe to assess which traits determine a species' mortality risk. We found that species-specific mortality anomalies from community mortality rate in a given drought were associated with plant hydraulic traits. Across all species, mortality was best predicted by a low hydraulic safety margin-the difference between typical minimum xylem water potential and that causing xylem dysfunction-and xylem vulnerability to embolism. Angiosperms and gymnosperms experienced roughly equal mortality risks. Our results provide broad support for the hypothesis that hydraulic traits capture key mechanisms determining tree death and highlight that physiological traits can improve vegetation model prediction of tree mortality during climate extremes.
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Wang HH, Wonkka CL, Grant WE, Rogers WE. Range expansion of invasive shrubs: implication for crown fire risk in forestlands of the southern USA. AOB PLANTS 2016; 8:plw012. [PMID: 26903488 PMCID: PMC4804204 DOI: 10.1093/aobpla/plw012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 02/13/2016] [Indexed: 06/05/2023]
Abstract
Non-native plant invasions and changing management activities have dramatically altered the structure and composition of forests worldwide. Invasive shrubs and fire suppression have led to increased densification and biomass accumulation in forest ecosystems of the southeastern USA. Notably, Chinese and European privets are rapid growing, shade-tolerant shrubs which number among the most aggressive invasive species in these forests. Privet encroachment has caused losses of native diversity, alteration of ecosystem processes and changes in community structure. The latter has become manifest through decreases in fine herbaceous fuels concurrent with increases in coarse woody fuels in forest understoreys. These alterations in fuel structure will potentially lead to less frequent, but more severe forest fires, which threaten important forest resources during extreme weather conditions. Drawing on extensive data sets compiled by the US Forest Service, we integrated statistical forecasting and analytical techniques within a spatially explicit, agent-based, simulation framework to predict potential range expansion of Chinese and European privet (Ligustrum sinenseandL. vulgare) and the associated increase in crown fire risk over the next two decades in forestlands of Mississippi and Alabama. Our results indicate that probability of invasion is positively associated with elevation, adjacency (within 300 m) to water bodies, mean daily maximum temperature, site productivity and private land ownership, and is negatively associated with slope, stand age, artificial regeneration, distance to the nearest road and fire disturbance. Our projections suggest the total area invaded will increase from 1.36 to ≈31.39% of all forestlands in Mississippi and Alabama (≈7 million hectares) and the annual frequency of crown fires in these forestlands will approximately double within the next two decades. Such time series projections of annual range expansions and crown fire frequency should provide land managers and restoration practitioners with an invasion chronology upon which to base proactive management plans.
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Affiliation(s)
- Hsiao-Hsuan Wang
- Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Carissa L Wonkka
- Department of Ecosystem Science and Management, Texas A&M University, College Station, TX 77843, USA Present address: Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE 68583, USA
| | - William E Grant
- Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843, USA
| | - William E Rogers
- Department of Ecosystem Science and Management, Texas A&M University, College Station, TX 77843, USA
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Moore GW, Edgar CB, Vogel JG, Washington-Allen RA, March RG, Zehnder R. Tree mortality from an exceptional drought spanning mesic to semiarid ecoregions. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2016; 26:602-11. [PMID: 27209798 DOI: 10.1890/15-0330] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Significant areas of the southern USA periodically experience intense drought that can lead to episodic tree mortality events. Because drought tolerance varies among species and size of trees, such events can alter the structure and function of terrestrial ecosystem in ways that are difficult to detect with local data sets or solely with remote-sensing platforms. We investigated a widespread tree mortality event that resulted from the worst 1-year drought on record for the state of Texas, USA. The drought affected ecoregions spanning mesic to semiarid climate zones and provided a unique opportunity to test hypotheses related to how trees of varying genus and size were affected. The study was based on an extensive set of 599 distributed plots, each 0.16 ha, surveyed in the summer following the drought. In each plot, dead trees larger than 12.7 cm in diameter were counted, sized, and identified to the genus level. Estimates of total mortality were obtained for each of 10 regions using a combination of design-based estimators and calibrated remote sensing using MODIS 1-yr change in normalized difference vegetation index products developed by the U.S. Forest Service. As compared with most of the publicized extreme die-off events, this study documents relatively low rates of mortality occurring over a very large area. However, statewide, regional tree mortality was massive, with an estimated 6.2% of the live trees perishing, nearly nine times greater than normal annual mortality. Dead tree diameters averaged larger than the live trees for most ecoregions, and this trend was most pronounced in the wetter climate zones, suggesting a potential re-ordering of species dominance and downward trend in tree size that was specific to climatic regions. The net effect on carbon storage was estimated to be a redistribution of 24-30 Tg C from the live tree to dead tree carbon pool. The dead tree survey documented drought mortality in more than 29 genera across all regions, and surprisingly, drought resistant and sensitive species fared similarly in some regions. Both angiosperms and gymnosperms were affected. These results highlight that drought-driven mortality alters forest structure differently across climatic regions and genera.
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Evidence on the Adaptive Recruitment of Chinese Cork Oak (Quercus variabilis Bl.): Influence on Repeated Germination and Constraint Germination by Food-Hoarding Animals. FORESTS 2016. [DOI: 10.3390/f7020047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Berdanier AB, Clark JS. Multiyear drought-induced morbidity preceding tree death in southeastern U.S. forests. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2016; 26:17-23. [PMID: 27039506 DOI: 10.1890/15-0274] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Recent forest diebacks, combined with threats of future drought, focus attention on the extent to which tree death is caused by catastrophic events as opposed to chronic declines in health that accumulate over years. While recent attention has focused on large-scale diebacks, there is concern that increasing drought stress and chronic morbidity may have pervasive impacts on forest composition in many regions. Here we use long-term, whole-stand inventory data from southeastern U.S. forests to show that trees exposed to drought experience multiyear declines in growth prior to mortality. Following a severe, multiyear drought, 72% of trees that did not recover their pre-drought growth rates died within 10 yr. This pattern was mediated by local moisture availability. As an index of morbidity prior to death, we calculated the difference in cumulative growth after drought relative to surviving conspecifics. The strength of drought-induced morbidity varied among species and was correlated with drought tolerance. These findings support the ability of trees to avoid death during drought events but indicate shifts that could occur over decades. Tree mortality following drought is predictable in these ecosystems based on growth declines, highlighting an opportunity to address multiyear drought-induced morbidity in models, experiments, and management decisions.
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