1
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Baden HM, Colchero F, Cubey R, Dahlgren JP. Aging varies greatly within a single genus: A demographic study of Rhododendron spp. in botanic gardens. Am J Bot 2023; 110:e16247. [PMID: 37792540 DOI: 10.1002/ajb2.16247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 09/19/2023] [Accepted: 09/19/2023] [Indexed: 10/06/2023]
Abstract
PREMISE There is mounting evidence that age matters in plant demography, but also indications that relationships between age and demographic rates may vary significantly among species. Age-based plant demographic data, however, are time-consuming to collect and still lacking for most species, and little is known about general patterns across species or what may drive differences. METHODS We used individual birth and death records for 12 Rhododendron species from botanic gardens and conducted Bayesian survival trajectory analyses to assess how mortality changed with age. We calculated the demographic measures of aging rate, life-span equality, and life expectancy for each species, and assessed their relationships with the climatic conditions at species' sites of ancestral origin and with taxonomic group (subgenus). RESULTS We found substantial among-species variation in survival trajectories, with mortality increasing, decreasing, or remaining constant with advancing age. Moreover, we found no relationships between demographic measures and ancestral climatic conditions but there were statistically significant differences among taxonomic groups in the rate of change in mortality with age (aging rate). CONCLUSIONS We conclude that demographic consequences of aging can differ qualitatively, even among species in the same genus. In addition, taxonomic trends in aging rates indicate they may be genetically determined, though evolutionary drivers are still unclear. Furthermore, we suggest there is untapped potential in using botanic garden records in future studies on plant life history.
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Affiliation(s)
- H Maria Baden
- Interdisciplinary Centre on Population Dynamics, University of Southern Denmark
- Department of Biology, University of Southern Denmark
| | - Fernando Colchero
- Interdisciplinary Centre on Population Dynamics, University of Southern Denmark
- Department of Mathematics and Data Science, University of Southern Denmark
| | - Rob Cubey
- Plant Records, Royal Botanic Garden Edinburgh, United Kingdom
| | - Johan P Dahlgren
- Interdisciplinary Centre on Population Dynamics, University of Southern Denmark
- Department of Biology, University of Southern Denmark
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2
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Fortunel C. Winds of change. A commentary on 'Demographic trade-offs and functional shifts in a hurricane-impacted tropical forest'. Ann Bot 2023; 131:iii-v. [PMID: 37462966 PMCID: PMC10457024 DOI: 10.1093/aob/mcad076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/27/2023]
Abstract
This article comments on:
María Natalia Umaña, Jessica Needham, Jimena Forero-Montaña, Christopher J. Nytch, Nathan G. Swenson, Jill Thompson, María Uriarte and Jess K. Zimmerman. Demographic trade-offs and functional shifts in a hurricane-impacted tropical forest, Annals of Botany, Volume 131, Issue 7, 6 June 2023, Pages 1051–1060, https://doi.org/10.1093/aob/mcad004
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Affiliation(s)
- Claire Fortunel
- AMAP (Botanique et Modélisation de l’Architecture des Plantes et des Végétations), Université de Montpellier, CIRAD, CNRS, INRAE, IRD, Montpellier, France
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3
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Moutouama JK, Gaoue OG. Effects of range and niche position on the population dynamics of a tropical plant. Ecology 2023; 104:e3990. [PMID: 36756774 DOI: 10.1002/ecy.3990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 01/02/2023] [Accepted: 01/09/2023] [Indexed: 02/10/2023]
Abstract
The center-periphery hypothesis predicts a decline in population performance toward the periphery of a species' range, reflecting an alteration of environmental conditions at range periphery. However, the rare demographic tests of this hypothesis failed to disentangle the role of geography from that of ecological niche and are biased toward temperate regions. We hypothesized that, because species are expected to experience optimal abiotic conditions at their climatic niche center, (1) central populations will have better demographic growth, survival, and fertility than peripheral populations. As a result, (2) central populations are expected to have higher growth rates than peripheral populations. Peripheral populations are expected to decline, thus limiting species range expansion beyond these boundaries. Because peripheral populations are expected to be in harsh environmental conditions, (3) population growth rate will be more sensitive to perturbation of survival-growth rather than fertility in peripheral populations. Finally, we hypothesized that (4) soils properties will drive the variations in population growth rates for narrowly distributed species for which small scale ecological factors could outweigh landscape level drivers. To test these hypotheses, we studied the demography of Thunbergia atacorensis (Acanthaceae), a range-limited herb in West Africa. We collected three years of demographic data to parameterize an integral projection model (IPM) and estimated population level demographic statistics. Demographic vital rates and population growth rates did not change significantly with distance from geographic or climatic center, contrary to predictions. However, populations at the center of the geographic range were demographically more resilient to perturbation than those at the periphery. Soil nitrogen was the main driver of population growth rate variation. The relative influence of survival-growth on population growth rates exceeded that of fertility at the geographic range center while we observed the opposite pattern for climatic niche. Our study highlights the importance of local scale processes in shaping the dynamics and distribution of range-limited species. Our findings also suggest that the distinction between geographic distribution and climatic niche is important for a robust demographic test of the center-periphery hypothesis.
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Affiliation(s)
- Jacob K Moutouama
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee, USA.,Program in Ecology and Evolutionary Biology, Department of Biosciences, Rice University, Houston, Texas, USA
| | - Orou G Gaoue
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee, USA.,Faculty of Agronomy, University of Parakou, Parakou, Benin.,Department of Geography, Environmental Management and Energy Studies, University of Johannesburg, APK Campus, Johannesburg, South Africa
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4
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Maschler J, Bialic‐Murphy L, Wan J, Andresen LC, Zohner CM, Reich PB, Lüscher A, Schneider MK, Müller C, Moser G, Dukes JS, Schmidt IK, Bilton MC, Zhu K, Crowther TW. Links across ecological scales: Plant biomass responses to elevated CO 2. Glob Chang Biol 2022; 28:6115-6134. [PMID: 36069191 PMCID: PMC9825951 DOI: 10.1111/gcb.16351] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 07/06/2022] [Indexed: 06/04/2023]
Abstract
The degree to which elevated CO2 concentrations (e[CO2 ]) increase the amount of carbon (C) assimilated by vegetation plays a key role in climate change. However, due to the short-term nature of CO2 enrichment experiments and the lack of reconciliation between different ecological scales, the effect of e[CO2 ] on plant biomass stocks remains a major uncertainty in future climate projections. Here, we review the effect of e[CO2 ] on plant biomass across multiple levels of ecological organization, scaling from physiological responses to changes in population-, community-, ecosystem-, and global-scale dynamics. We find that evidence for a sustained biomass response to e[CO2 ] varies across ecological scales, leading to diverging conclusions about the responses of individuals, populations, communities, and ecosystems. While the distinct focus of every scale reveals new mechanisms driving biomass accumulation under e[CO2 ], none of them provides a full picture of all relevant processes. For example, while physiological evidence suggests a possible long-term basis for increased biomass accumulation under e[CO2 ] through sustained photosynthetic stimulation, population-scale evidence indicates that a possible e[CO2 ]-induced increase in mortality rates might potentially outweigh the effect of increases in plant growth rates on biomass levels. Evidence at the global scale may indicate that e[CO2 ] has contributed to increased biomass cover over recent decades, but due to the difficulty to disentangle the effect of e[CO2 ] from a variety of climatic and land-use-related drivers of plant biomass stocks, it remains unclear whether nutrient limitations or other ecological mechanisms operating at finer scales will dampen the e[CO2 ] effect over time. By exploring these discrepancies, we identify key research gaps in our understanding of the effect of e[CO2 ] on plant biomass and highlight the need to integrate knowledge across scales of ecological organization so that large-scale modeling can represent the finer-scale mechanisms needed to constrain our understanding of future terrestrial C storage.
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Affiliation(s)
- Julia Maschler
- Institute of Integrative BiologyETH Zurich (Swiss Federal Institute of Technology)ZurichSwitzerland
| | - Lalasia Bialic‐Murphy
- Institute of Integrative BiologyETH Zurich (Swiss Federal Institute of Technology)ZurichSwitzerland
| | - Joe Wan
- Institute of Integrative BiologyETH Zurich (Swiss Federal Institute of Technology)ZurichSwitzerland
| | | | - Constantin M. Zohner
- Institute of Integrative BiologyETH Zurich (Swiss Federal Institute of Technology)ZurichSwitzerland
| | - Peter B. Reich
- Department of Forest ResourcesUniversity of MinnesotaSt. PaulMinnesotaUSA
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityPenrithNew South WalesAustralia
- Institute for Global Change Biology, and School for the Environment and SustainabilityUniversity of MichiganAnn ArborMichiganUSA
| | - Andreas Lüscher
- ETH ZurichInstitute of Agricultural ScienceZurichSwitzerland
- Agroscope, Forage Production and Grassland SystemsZurichSwitzerland
| | - Manuel K. Schneider
- ETH ZurichInstitute of Agricultural ScienceZurichSwitzerland
- Agroscope, Forage Production and Grassland SystemsZurichSwitzerland
| | - Christoph Müller
- Institute of Plant EcologyJustus Liebig UniversityGiessenGermany
- School of Biology and Environmental Science and Earth InstituteUniversity College DublinDublinIreland
| | - Gerald Moser
- Institute of Plant EcologyJustus Liebig UniversityGiessenGermany
| | - Jeffrey S. Dukes
- Department of Forestry and Natural ResourcesPurdue UniversityWest LafayetteIndianaUSA
- Department of Biological SciencesPurdue UniversityWest LafayetteIndianaUSA
- Department of Global EcologyCarnegie Institution for ScienceStanfordCaliforniaUSA
| | - Inger Kappel Schmidt
- Geosciences and Natural Resource ManagementUniversity of CopenhagenCopenhagenDenmark
| | - Mark C. Bilton
- Department of Agriculture and Natural Resources SciencesNamibia University of Science and Technology (NUST)WindhoekNamibia
| | - Kai Zhu
- Department of Environmental StudiesUniversity of CaliforniaSanta CruzCaliforniaUSA
| | - Thomas W. Crowther
- Institute of Integrative BiologyETH Zurich (Swiss Federal Institute of Technology)ZurichSwitzerland
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5
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Yang X, Angert AL, Zuidema PA, He F, Huang S, Li S, Li SL, Chardon NI, Zhang J. The role of demographic compensation in stabilising marginal tree populations in North America. Ecol Lett 2022; 25:1676-1689. [PMID: 35598109 DOI: 10.1111/ele.14028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 02/22/2022] [Accepted: 04/25/2022] [Indexed: 12/21/2022]
Abstract
Demographic compensation-the opposing responses of vital rates along environmental gradients-potentially delays anticipated species' range contraction under climate change, but no consensus exists on its actual contribution. We calculated population growth rate (λ) and demographic compensation across the distributional ranges of 81 North American tree species and examined their responses to simulated warming and tree competition. We found that 43% of species showed stable population size at both northern and southern edges. Demographic compensation was detected in 25 species, yet 15 of them still showed a potential retraction from southern edges, indicating that compensation alone cannot maintain range stability. Simulated climatic warming caused larger decreases in λ for most species and weakened the effectiveness of demographic compensation in stabilising ranges. These findings suggest that climate stress may surpass the limited capacity of demographic compensation and pose a threat to the viability of North American tree populations.
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Affiliation(s)
- Xianyu Yang
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, Research Center of Global Change and Complex Ecosystems, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, P. R. China.,Shanghai Institute of Pollution Control and Ecological Security, Shanghai, P.R. China.,Biodiversity Research Centre and Department of Botany, University of British Columbia, Vancouver, Canada
| | - Amy L Angert
- Biodiversity Research Centre and Department of Botany, University of British Columbia, Vancouver, Canada
| | - Pieter A Zuidema
- Forest Ecology and Forest Management Group, Wageningen University, Wageningen, the Netherlands
| | - Fangliang He
- Department of Renewable Resources, University of Alberta, Edmonton, Canada
| | - Shongming Huang
- Government of Alberta, Department of Agriculture, Forestry and Rural Economic Development, Edmonton, Canada
| | - Shouzhong Li
- Key Laboratory for Subtropical Mountain Ecology, Ministry of Science and Technology and Fujian Province Funded, School of Geographical Sciences, Fujian Normal University, Fuzhou, P. R. China
| | - Shou-Li Li
- State Key Laboratory of Grassland Agro-ecosystems, and College of Pastoral, Agriculture Science and Technology, Lanzhou University, Lanzhou, P. R. China
| | - Nathalie I Chardon
- Biodiversity Research Centre and Department of Botany, University of British Columbia, Vancouver, Canada
| | - Jian Zhang
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, Research Center of Global Change and Complex Ecosystems, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, P. R. China.,Shanghai Institute of Pollution Control and Ecological Security, Shanghai, P.R. China
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6
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Kazakou E, Fried G, Cheptou P, Gimenez O. Does seed mass drive interspecies variation in the effect of management practices on weed demography? Ecol Evol 2021; 11:13166-13174. [PMID: 34646460 PMCID: PMC8495798 DOI: 10.1002/ece3.8038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 07/29/2021] [Accepted: 08/02/2021] [Indexed: 11/18/2022] Open
Abstract
Optimizing the effect of management practices on weed population dynamics is challenging due to the difficulties in inferring demographic parameters in seed banks and their response to disturbance. Here, we used a long-term plant survey between 2006 and 2012 in 46 French vineyards and quantified the effects of management practices (tillage, mowing, and herbicide) on colonization, germination, and seed survival of 30 weed species in relation to their seed mass. To do so, we used a recent statistical approach to reliably estimate demographic parameters for plant populations with a seed bank using time series of presence-absence data, which we extended to account for interspecies variation in the effects of management practices on demographic parameters. Our main finding was that when the level of disturbance increased (i.e., in plots with a higher number of herbicides, tillage, or mowing treatments), colonization success and survival in large-seeded species increased faster than in small-seeded species. High disturbance through tillage increased survival in the seed bank of species with high seed mass. The application of herbicides increased germination, survival, and colonization probabilities of species with high seed mass. Mowing, representing habitats more competitive for light, increased the survival of species with high seed mass. Overall, the strong relationships between the effects of management practices and seed mass provide an indicator for predicting the dynamics of weed communities under disturbance.
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Affiliation(s)
- Elena Kazakou
- CEFEUniv MontpellierCNRSEPHE, IRDUniv Paul Valéry Montpellier 3Institut AgroMontpellier SupagroMontpellierFrance
| | - Guillaume Fried
- AnsesLaboratoire de la Santé des VégétauxUnité Entomologie et Plantes InvasivesMontferrier‐sur‐LezFrance
| | | | - Olivier Gimenez
- CEFEUniv MontpellierCNRSEPHE, IRDUniv Paul Valéry Montpellier 3MontpellierFrance
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7
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Miller RG, Fontaine JB, Merritt DJ, Miller BP, Enright NJ. Experimental seed sowing reveals seedling recruitment vulnerability to unseasonal fire. Ecol Appl 2021; 31:e02411. [PMID: 34255387 DOI: 10.1002/eap.2411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 02/25/2021] [Accepted: 03/22/2021] [Indexed: 06/13/2023]
Abstract
Unseasonal fire occurrence is increasing globally, driven by climate change and other human activity. Changed timing of fire can inhibit postfire seedling recruitment through interactions with plant phenology (the timing of key processes, e.g., flower initiation, seed production, dispersal, germination), and therefore threaten the persistence of many plant species. Although empirical evidence from winter-rainfall ecosystems shows that optimal seedling recruitment is expected following summer and autumn (dry season) fires, we sought experimental evidence isolating the mechanisms of poor recruitment following unseasonal (wet season) fire. We implemented a seed-sowing experiment using nine species native to fire-prone, Mediterranean-climate woodlands in southwestern Australia to emulate the timing of postfire recruitment and test key mechanisms of fire seasonality effects. For seeds sown during months when fire is unseasonal (i.e., August-September: end of the wet winter season), seedling recruitment was reduced by up to 99% relative to seeds sown during seasonal fire months (i.e., May-June: end of the dry summer season) because of varying seed persistence, seedling emergence, and seedling survival. We found that up to 70 times more seedlings emerged when seeds were sown during seasonal fire months compared to when seeds were sown during unseasonal fire months. The few seedlings that emerged from unseasonal sowings all died with the onset of the dry season. Of the seeds that failed to germinate from unseasonal sowings, only 2% survived exposure on the soil surface over the ensuing hot and dry summer. Our experimental results demonstrate the potential for unseasonal fire to inhibit seedling recruitment via impacts on pregermination seed persistence and seedling establishment. As ongoing climate change lengthens fire seasons (i.e., unseasonal wildfires become more common) and managed fires are implemented further outside historically typical fire seasons, postfire seedling recruitment may become more vulnerable to failure, causing shifts in plant community composition towards those with fewer species solely dependent on seeds for regeneration.
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Affiliation(s)
- Russell G Miller
- Environmental and Conservation Sciences, Murdoch University, Murdoch, Perth, 6150, Western Australia, Australia
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, 1 Kattidj Close, Kings Park, Perth, 6005, Western Australia, Australia
| | - Joseph B Fontaine
- Environmental and Conservation Sciences, Murdoch University, Murdoch, Perth, 6150, Western Australia, Australia
| | - David J Merritt
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, 1 Kattidj Close, Kings Park, Perth, 6005, Western Australia, Australia
- School of Biological Sciences, University of Western Australia, Crawley, Perth, 6009, Western Australia, Australia
| | - Ben P Miller
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, 1 Kattidj Close, Kings Park, Perth, 6005, Western Australia, Australia
- School of Biological Sciences, University of Western Australia, Crawley, Perth, 6009, Western Australia, Australia
| | - Neal J Enright
- Environmental and Conservation Sciences, Murdoch University, Murdoch, Perth, 6150, Western Australia, Australia
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8
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Evers SM, Knight TM, Inouye DW, Miller TEX, Salguero-Gómez R, Iler AM, Compagnoni A. Lagged and dormant season climate better predict plant vital rates than climate during the growing season. Glob Chang Biol 2021; 27:1927-1941. [PMID: 33586192 DOI: 10.1111/gcb.15519] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 12/19/2020] [Accepted: 12/28/2020] [Indexed: 06/12/2023]
Abstract
Understanding the effects of climate on the vital rates (e.g., survival, development, reproduction) and dynamics of natural populations is a long-standing quest in ecology, with ever-increasing relevance in the face of climate change. However, linking climate drivers to demographic processes requires identifying the appropriate time windows during which climate influences vital rates. Researchers often do not have access to the long-term data required to test a large number of windows, and are thus forced to make a priori choices. In this study, we first synthesize the literature to assess current a priori choices employed in studies performed on 104 plant species that link climate drivers with demographic responses. Second, we use a sliding-window approach to investigate which combination of climate drivers and temporal window have the best predictive ability for vital rates of four perennial plant species that each have over a decade of demographic data (Helianthella quinquenervis, Frasera speciosa, Cylindriopuntia imbricata, and Cryptantha flava). Our literature review shows that most studies consider time windows in only the year preceding the measurement of the vital rate(s) of interest, and focus on annual or growing season temporal scales. In contrast, our sliding-window analysis shows that in only four out of 13 vital rates the selected climate drivers have time windows that align with, or are similar to, the growing season. For many vital rates, the best window lagged more than 1 year and up to 4 years before the measurement of the vital rate. Our results demonstrate that for the vital rates of these four species, climate drivers that are lagged or outside of the growing season are the norm. Our study suggests that considering climatic predictors that fall outside of the most recent growing season will improve our understanding of how climate affects population dynamics.
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Affiliation(s)
- Sanne M Evers
- Institute of Biology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - Tiffany M Knight
- Institute of Biology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
- Department of Community Ecology, Helmholtz Centre for Environmental Research - UFZ, Halle (Saale), Germany
| | - David W Inouye
- Department of Biology, University of Maryland, College Park, MD, USA
- Rocky Mountain Biological Laboratory, Crested Butte, CO, USA
| | - Tom E X Miller
- Program in Ecology and Evolutionary Biology, Department of BioSciences, Rice University, Houston, TX, USA
| | | | - Amy M Iler
- Rocky Mountain Biological Laboratory, Crested Butte, CO, USA
- The Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden, Glencoe, IL, USA
| | - Aldo Compagnoni
- Institute of Biology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
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9
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Fill JM, Crandall RM. Stronger Evidence Needed for Global Fire Season Effects. Trends Ecol Evol 2020; 35:867-8. [PMID: 32703704 DOI: 10.1016/j.tree.2020.06.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/10/2020] [Accepted: 06/26/2020] [Indexed: 01/11/2023]
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10
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Töpper JP, Meineri E, Olsen SL, Rydgren K, Skarpaas O, Vandvik V. The devil is in the detail: Nonadditive and context-dependent plant population responses to increasing temperature and precipitation. Glob Chang Biol 2018; 24:4657-4666. [PMID: 29851242 DOI: 10.1111/gcb.14336] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/18/2018] [Accepted: 05/19/2018] [Indexed: 05/13/2023]
Abstract
In climate change ecology, simplistic research approaches may yield unrealistically simplistic answers to often more complicated problems. In particular, the complexity of vegetation responses to global climate change begs a better understanding of the impacts of concomitant changes in several climatic drivers, how these impacts vary across different climatic contexts, and of the demographic processes underlying population changes. Using a replicated, factorial, whole-community transplant experiment, we investigated regional variation in demographic responses of plant populations to increased temperature and/or precipitation. Across four perennial forb species and 12 sites, we found strong responses to both temperature and precipitation change. Changes in population growth rates were mainly due to changes in survival and clonality. In three of the four study species, the combined increase in temperature and precipitation reflected nonadditive, antagonistic interactions of the single climatic changes for population growth rate and survival, while the interactions were additive and synergistic for clonality. This disparity affects the persistence of genotypes, but also suggests that the mechanisms behind the responses of the vital rates differ. In addition, survival effects varied systematically with climatic context, with wetter and warmer + wetter transplants showing less positive or more negative responses at warmer sites. The detailed demographic approach yields important mechanistic insights into how concomitant changes in temperature and precipitation affect plants, which makes our results generalizable beyond the four study species. Our comprehensive study design illustrates the power of replicated field experiments in disentangling the complex relationships and patterns that govern climate change impacts across real-world species and landscapes.
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Affiliation(s)
- Joachim P Töpper
- Norwegian Institute for Nature Research, Bergen, Norway
- Institute of Natural Sciences, Western Norway University of Applied Sciences, Sogndal, Norway
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Eric Meineri
- Department of Biological Sciences, University of Bergen, Bergen, Norway
- CNRS, IRD, IMBE, Aix Marseille University, University of Avignon, Marseille, France
| | - Siri L Olsen
- Norwegian Institute for Nature Research, Oslo, Norway
| | - Knut Rydgren
- Institute of Natural Sciences, Western Norway University of Applied Sciences, Sogndal, Norway
| | - Olav Skarpaas
- Norwegian Institute for Nature Research, Oslo, Norway
- Natural History Museum, University of Oslo, Oslo, Norway
| | - Vigdis Vandvik
- Department of Biological Sciences, University of Bergen, Bergen, Norway
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11
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Leverkus AB, Rey Benayas JM, Castro J. Shifting demographic conflicts across recruitment cohorts in a dynamic post-disturbance landscape. Ecology 2018; 97:2628-2639. [PMID: 27859134 DOI: 10.1002/ecy.1527] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 06/18/2016] [Accepted: 06/27/2016] [Indexed: 11/12/2022]
Abstract
Seed dispersal effectiveness, which measures the number of adult plant individuals produced by seed dispersal, is the product of the number of seeds dispersed and the probability a seed produces an adult. Directed dispersal to certain habitat types may enhance some stages of recruitment but disfavor others, generating demographic conflicts in plant ontogeny. We asked whether temporal changes in habitat features may affect the distribution of seedlings recruited from dispersed acorns, and whether this could induce shifts in the life-stage conflicts experienced by successive cohorts of naturally recruited plants. As early successional habitats are characterized by rapid change, we used a burnt pine stand in southern Spain to monitor the recruitment and performance of a major tree species (Quercus ilex) across 7 yr in four types of post-fire habitats. These differed in structure and included patches of unburnt forest and three management alternatives of burnt trees: logging, partial cutting, and nonintervention. Young oaks that resprouted after the fire were mainly located near acorn sources, while new seedlings initially emerged mostly in habitats with standing snags due to habitat selection by European jays, Garrulus glandarius, for dispersal. The dead pines gradually collapsed and attracted less dispersal, so subsequent seedling cohorts mainly recruited within patches of unburnt pines. These live pines enhanced the survival of the oaks located beneath their canopy but greatly reduced their growth as compared to the other post-fire habitats, thus representing a demographic conflict that was absent elsewhere. As a consequence of the directional shift in the habitat where seedlings recruited, successive seedling cohorts experienced a gradual improvement in their likelihood of survival but a reduction in growth. The progressive intensification of this life-stage conflict hinged on the reduction of vertical structures in the habitat with standing burnt pines. Recruitment success thus involved temporal variation in the habitat where recruitment occurred, likely resulting from changes in the direction of seed dispersal, and spatial variation in habitat suitability for seedling establishment and growth. Temporal changes in habitat structure can indirectly change the environment in which recruitment occurs, and consequently seed dispersal effectiveness, by shifting the direction of seed dispersal.
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Affiliation(s)
- Alexandro B Leverkus
- Departamento de Ecología, Facultad de Ciencias, Universidad de Granada, E-18071, Granada, Spain
| | - José María Rey Benayas
- Departamento de Ciencias de la Vida, UD Ecología, Universidad de Alcalá, Edificio de Ciencias, 28805, Alcalá de Henares, Spain
| | - Jorge Castro
- Departamento de Ecología, Facultad de Ciencias, Universidad de Granada, E-18071, Granada, Spain
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Tenhumberg B, Crone EE, Ramula S, Tyre AJ. Time-lagged effects of weather on plant demography: drought and Astragalus scaphoides. Ecology 2018; 99:915-925. [PMID: 29380874 DOI: 10.1002/ecy.2163] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 12/20/2017] [Accepted: 01/02/2018] [Indexed: 01/05/2023]
Abstract
Temperature and precipitation determine the conditions where plant species can occur. Despite their significance, to date, surprisingly few demographic field studies have considered the effects of abiotic drivers. This is problematic because anticipating the effect of global climate change on plant population viability requires understanding how weather variables affect population dynamics. One possible reason for omitting the effect of weather variables in demographic studies is the difficulty in detecting tight associations between vital rates and environmental drivers. In this paper, we applied Functional Linear Models (FLMs) to long-term demographic data of the perennial wildflower, Astragalus scaphoides, and explored sensitivity of the results to reduced amounts of data. We compared models of the effect of average temperature, total precipitation, or an integrated measure of drought intensity (standardized precipitation evapotranspiration index, SPEI), on plant vital rates. We found that transitions to flowering and recruitment in year t were highest if winter/spring of year t was wet (positive effect of SPEI). Counterintuitively, if the preceding spring of year t - 1 was wet, flowering probabilities were decreased (negative effect of SPEI). Survival of vegetative plants from t - 1 to t was also negatively affected by wet weather in the spring of year t - 1 and, for large plants, even wet weather in the spring of t - 2 had a negative effect. We assessed the integrated effect of all vital rates on life history performance by fitting FLMs to the asymptotic growth rate, log(λt). Log(λt) was highest if dry conditions in year t - 1 were followed by wet conditions in the year t. Overall, the positive effects of wet years exceeded their negative effects, suggesting that increasing frequency of drought conditions would reduce population viability of A. scaphoides. The drought signal weakened when reducing the number of monitoring years. Substituting space for time did not recover the weather signal, probably because the weather variables varied little between sites. We detected the SPEI signal when the analysis included data from two sites monitored over 20 yr (2 × 20 observations), but not when analyzing data from four sites monitored over 10 yr (4 × 10 observations).
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Affiliation(s)
- Brigitte Tenhumberg
- School of Biological Sciences and Department of Mathematics, University of Nebraska, Lincoln, Nebraska, 68588, USA
| | - Elizabeth E Crone
- Department of Biology, Tufts University, Medford, Massachusetts, 02155, USA
| | - Satu Ramula
- Section of Ecology, Department of Biology, University of Turku, FI-20014, Turku, Finland
| | - Andrew J Tyre
- School of Natural Resources, University of Nebraska, Lincoln, Nebraska, 68583, USA
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Martínez-Ramos M, Ortiz-Rodríguez IA, Piñero D, Dirzo R, Sarukhán J. Anthropogenic disturbances jeopardize biodiversity conservation within tropical rainforest reserves. Proc Natl Acad Sci U S A 2016; 113:5323-8. [PMID: 27071122 DOI: 10.1073/pnas.1602893113] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Anthropogenic disturbances affecting tropical forest reserves have been documented, but their ecological long-term cumulative effects are poorly understood. Habitat fragmentation and defaunation are two major anthropogenic threats to the integrity of tropical reserves. Based on a long-term (four decades) study, we document how these disturbances synergistically disrupt ecological processes and imperil biodiversity conservation and ecosystem functioning at Los Tuxtlas, the northernmost tropical rainforest reserve in the Americas. Deforestation around this reserve has reduced the reserve to a medium-sized fragment (640 ha), leading to an increased frequency of canopy-gap formation. In addition, hunting and habitat loss have caused the decline or local extinction of medium and large herbivores. Combining empirical, experimental, and modeling approaches, we support the hypothesis that such disturbances produced a demographic explosion of the long-lived (≈120 y old, maximum height of 7 m) understory palm Astrocaryum mexicanum, whose population has increased from 1,243-4,058 adult individuals per hectare in only 39 y (annual growth rate of ca 3%). Faster gap formation increased understory light availability, enhancing seed production and the growth of immature palms, whereas release from mammalian herbivory and trampling increased survival of seedlings and juveniles. In turn, the palm's demographic explosion was followed by a reduction of tree species diversity, changing forest composition, altering the relative contribution of trees to forest biomass, and disrupting litterfall dynamics. We highlight how indirect anthropogenic disturbances (e.g., palm proliferation) on otherwise protected areas threaten tropical conservation, a phenomenon that is currently eroding the planet's richest repositories of biodiversity.
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Young AG, Broadhurst LM, Thrall PH. Non-additive effects of pollen limitation and self-incompatibility reduce plant reproductive success and population viability. Ann Bot 2012; 109:643-53. [PMID: 22184620 PMCID: PMC3278296 DOI: 10.1093/aob/mcr290] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
BACKGROUND AND AIMS Mating system is a primary determinant of the ecological and evolutionary dynamics of wild plant populations. Pollen limitation and loss of self-incompatibility genotypes can both act independently to reduce seed set and these effects are commonly observed in fragmented landscapes. This study used a simulation modelling approach to assess the interacting effects of these two processes on plant reproductive performance and population viability for a range of pollination likelihood, self-incompatibility systems and S-allele richness conditions. METHODS A spatially explicit, individual-based, genetic and demographic simulation model parameterized to represent a generic self-incompatible, short-lived perennial herb was used to conduct simulation experiments in which pollination probability, self-incompatibility type (gametophytic and sporophytic) and S-allele richness were systematically varied in combination to assess their independent and interacting effects on the demographic response variables of mate availability, seed set, population size and population persistence. KEY RESULTS Joint effects of reduced pollination probability and low S-allele richness were greater than independent effects for all demographic response variables except population persistence under high pollinator service (>50 %). At intermediate values of 15-25 % pollination probability, non-linear interactions with S-allele richness generated significant reductions in population performance beyond those expected by the simple additive effect of each independently. This was due to the impacts of reduced effective population size on the ability of populations to retain S alleles and maintain mate availability. Across a limited set of pollination and S-allele conditions (P = 0·15 and S = 20) populations with gametophytic SI showed reduced S-allele erosion relative to those with sporophytic SI, but this had limited effects on individual fecundity and translated into only modest increases in population persistence. CONCLUSIONS Interactions between pollen limitation and loss of S alleles have the potential to significantly reduce the viability of populations of a few hundred plants. Population decline may occur more rapidly than expected when pollination probabilities drop below 25 % and S alleles are fewer than 20 due to non-additive interactions. These are likely to be common conditions experienced by plants in small populations in fragmented landscapes and are also those under which differences in response between gameptophytic and sporophtyic systems are observed.
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Abstract
It is an axiom of life-history theory that reproduction involves age-specific costs in terms of survival or future reproduction. The measurement of costs of reproduction in plants is difficult, and few field studies have measured these costs in terms of fitness or demographic components, thus creating a hiatus between theory and data. In this article, we describe methods for overcoming the problem, illustrated by a field study of balsam fir. We used serial correlation and a permutation test to detect growth costs of reproduction and show how these translate into demographic costs when relative tree size (and therefore growth) is critical to survival. Using chronosequences, we reconstructed the age- and size-specific dynamics of a subalpine population of Abies balsamea. A matrix model describing these dynamics was then used to estimate age- and size-specific probabilities of future survival to maturity ([Formula: see text]). By using a regression model of the relationship between tree size, age, and [Formula: see text], we were able to estimate the maximum age-specific demographic cost of reproduction for trees of all ages. The shape of the age-specific cost curve for A. balsamea may explain why, contrary to a previously published hypothesis, age at first reproduction in A. balsamea does not vary between wave-regenerating and normal populations.
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