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Fogarty DT, Beadle M, Allen CR, Bielski C, Twidwell D. Woody plant reinvasion shortens the lifespan of grassland restoration treatments. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2025; 374:124020. [PMID: 39788049 DOI: 10.1016/j.jenvman.2024.124020] [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: 09/13/2024] [Revised: 12/16/2024] [Accepted: 12/31/2024] [Indexed: 01/12/2025]
Abstract
An important question in restoration ecology is whether restored ecological regimes are more vulnerable to transitions back to a degraded state. In woody-invaded grasslands, high-intensity fire can collapse woody plant communities and induce a shift back to a grass-dominated regime. Yet, legacies from woody-dominated regimes often persist and it remains unclear whether restored regimes are at heightened vulnerability to reinvasion. In this study, we utilize a 17-year history of fire-based restoration in Nebraska's Loess Canyons Experimental Landscape to determine whether restored grassland regimes experience faster rates of Juniperus virginiana (eastern redcedar) reinvasion compared to the initial invasion process in adjacent grasslands. In addition, we examine whether reinvasion and invasion patterns are clearly differentiated based on former ecotonal boundaries between grassland and woodland regimes. Our results show that J. virginiana reinvasion of restored grassland regimes outpaced the initial invasion process in adjacent grasslands, providing evidence that restored grassland regimes are more vulnerable to transitions back to woody dominance. J. virginiana seedlings established sooner and increased faster in density and cover during reinvasion compared to the initial invasion process. Seedlings established 1-year post-fire in restored grassland regimes compared to 14-years post-fire in adjacent grasslands that were >40 m from the former grassland-woodland boundary. Reinvasion was initially easy to differentiate from invasion based on former ecotonal boundaries between grassland and woodland; however, reestablished juniper woodlands eventually began to expand into adjacent grasslands. Our findings demonstrate clear differences between reinvasion and invasion and highlight the need for management frameworks that explicitly account for reinvasion.
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Affiliation(s)
- Dillon T Fogarty
- School of Natural Resource Sciences, North Dakota State University, Fargo, ND, 58102, USA; Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA.
| | - Michele Beadle
- Biology Department, Saint John's University, Collegeville, MN, 56321, USA
| | - Craig R Allen
- Center for Resilience in Agricultural Working Landscapes, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Christine Bielski
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Dirac Twidwell
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
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2
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McKane RB, Halama JJ, Barnhart BL, Brookes AF, Djang KS, Chokshi S, Pettus PP, Groskinsky B, Grier G, Hawkins A, Watson D, Prentice J, Blair JM, Goodin DG, Johnson LC, Skibbe AM, Stieglitz M, Pan F, Abdelnour A. Estimation of flint hills tallgrass prairie productivity and fuel loads: a model-based synthesis and extrapolation of experimental data. LANDSCAPE ECOLOGY 2025; 40:1-27. [PMID: 40270488 PMCID: PMC12013701 DOI: 10.1007/s10980-024-02034-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Accepted: 12/23/2024] [Indexed: 04/25/2025]
Abstract
Context The > 25,000 km2 Flint Hills ecoregion in eastern Kansas and northeastern Oklahoma, USA, is an economically and ecologically important area encompassing the largest remaining tallgrass prairie ecosystem in North America. Prescribed fires are used routinely to control invasive woody species and improve forage production for the beef-cattle industry. However, burning releases harmful pollutants that, at times, contribute to air quality problems for communities across a multi-state area. Objectives Establish a modeling framework for synthesizing long-term ecological data in support of Flint Hills tallgrass prairie management goals for identifying how much, where, and when rangeland burning can be conducted to maximize ecological and economic benefits while minimizing regional air quality impacts. Methods We used EPA's VELMA ecohydrology model to synthesize long-term experimental data at the 35 km2 Konza Prairie Biological Station (KPBS) describing the effects of climate, fire, grazing, topography, and soil moisture and nutrient dynamics on tallgrass prairie productivity and fuel loads; and to spatially extrapolate that synthesis to estimate grassland productivity and fuel loads across the nearly 1000 times larger Flint Hills ecoregion to support prescribed burning smoke trajectory modeling using the State of Kansas implementation of the U.S. Forest Service BlueSky framework. Results VELMA provided a performance-tested synthesis of KPBS data from field observations and experiments, thereby establishing a tool for regionally simulating the combined effects of climate, fire, grazing, topography, soil moisture, and nutrients on tallgrass prairie productivity and fuel loads. VELMA's extrapolation of that synthesis allowed difficult-to-quantify fuel loads to be mapped across the Flint Hills to support environmental decision making, such as forecasting when, where, and how prescribed burning will have the least impact on downwind population centers. Conclusions Our regional spatial and temporal extrapolation of VELMA's KPBS data synthesis posits that the effects of integrated ecohydrological processes operate similarly across tallgrass prairie spatial scales. Based on multi-scale performance tests of the VELMA-BlueSky toolset, our multi-institution team is confident that it can assist stakeholders and decision makers in realistically exploring tallgrass prairie management options for balancing air quality, tallgrass prairie sustainability, and associated economic benefits for the Flint Hills ecoregion and downwind communities.
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Affiliation(s)
- Robert B McKane
- U.S. Environmental Protection Agency, Office of Research and Development, Corvallis, OR 97333, USA
| | - Jonathan J Halama
- U.S. Environmental Protection Agency, Office of Research and Development, Corvallis, OR 97333, USA
| | - Bradley L Barnhart
- U.S. Environmental Protection Agency, Office of Research and Development, Corvallis, OR 97333, USA
| | - Allen F Brookes
- U.S. Environmental Protection Agency, Office of Research and Development, Corvallis, OR 97333, USA
| | | | - Sonali Chokshi
- U.S. Environmental Protection Agency, Office of Research and Development, Corvallis, OR 97333, USA
| | - Paul P Pettus
- U.S. Environmental Protection Agency, Office of Research and Development, Corvallis, OR 97333, USA
| | - Brenda Groskinsky
- U.S. Environmental Protection Agency Region 7, Lenexa, KS 66219, USA
| | - Gina Grier
- U.S. Environmental Protection Agency Region 7, Lenexa, KS 66219, USA
| | - Andy Hawkins
- U.S. Environmental Protection Agency Region 7, Lenexa, KS 66219, USA
| | - Douglas Watson
- Kansas Department of Health and Environment, Topeka, KS 66612, USA
| | - Jayson Prentice
- Kansas Department of Health and Environment, Topeka, KS 66612, USA
| | - John M Blair
- Kansas State University, Manhattan, KS 66506, USA
| | | | | | | | | | - Feifei Pan
- Georgia Institute of Technology, Atlanta, GA 30332, USA
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3
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de Sousa HC, Malvasio A, Colli GR, Salguero-Gómez R. Severe fire regimes decrease resilience of ectothermic populations. J Anim Ecol 2024; 93:1656-1669. [PMID: 39308046 DOI: 10.1111/1365-2656.14188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 09/04/2024] [Indexed: 11/07/2024]
Abstract
Understanding populations' responses to environmental change is crucial for mitigating human-induced disturbances. Here, we test hypotheses regarding how three essential components of demographic resilience (resistance, compensation and recovery) co-vary along the distinct life histories of three lizard species exposed to variable, prescribed fire regimes. Using a Bayesian hierarchical framework, we estimate vital rates (survival, growth and reproduction) with 14 years of monthly individual-level data and mark-recapture models to parameterize stochastic integral projection models from five sites in Brazilian savannas, each historically subjected to different fire regimes. With these models, we investigate how weather, microclimate and ecophysiological traits of each species influence their vital rates, emergent life history traits and demographic resilience components in varying fire regimes. Overall, weather and microclimate are better predictors of the species' vital rates, rather than their ecophysiological traits. Our findings reveal that severe fire regimes increase populations' resistance but decrease compensation or recovery abilities. Instead, populations have higher compensatory and recovery abilities at intermediate degrees of fire severity. Additionally, we identify generation time and reproductive output as predictors of resilience trends across fire regimes and climate. Our analyses demonstrate that the probability and quantity of monthly reproduction are the proximal drivers of demographic resilience across the three species. Our findings suggest that populations surpass a tipping point in severe fire regimes and achieve an alternative stable state to persist. Thus, higher heterogeneity in fire regimes can increase the reproductive aspects and resilience of different populations and avoid high-severity regimes that homogenize the environment. Despite being more resistant, species with long generation times and low reproductive output take longer to recover and cannot compensate as much as species with faster paces of life. We emphasize how reproductive constraints, such as viviparity and fixed clutch sizes, impact the ability of ectothermic populations to benefit and recover from disturbances, underscoring their relevance in conservation assessments.
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Affiliation(s)
| | - Adriana Malvasio
- Universidade Federal do Tocantins-UFT, Palmas, Tocantins, Brazil
| | - Guarino Rinaldi Colli
- Departamento de Zoologia, Instituto de Ciências Biológicas, Universidade de Brasília-UnB, Brasília, Distrito Federal, Brazil
| | - Roberto Salguero-Gómez
- Department of Zoology, University of Oxford, Oxford, UK
- Evolutionary Demography Laboratory, Max Planck Institute for Demographic Research, Rostock, Germany
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4
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Wojciechowski AA, Blair JM, Collins SL, Baer SG. Heterogeneity promotes resilience in restored prairie: Implications for the environmental heterogeneity hypothesis. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2024; 34:e3006. [PMID: 39030911 DOI: 10.1002/eap.3006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 03/04/2024] [Accepted: 04/22/2024] [Indexed: 07/22/2024]
Abstract
Enhancing resilience in formerly degraded ecosystems is an important goal of restoration ecology. However, evidence for the recovery of resilience and its underlying mechanisms require long-term experiments and comparison with reference ecosystems. We used data from an experimental prairie restoration that featured long-term soil heterogeneity manipulations and data from two long-term experiments located in a comparable remnant (reference) prairie to (1) quantify the recovery of ecosystem functioning (i.e., productivity) relative to remnant prairie, (2) compare the resilience of restored and remnant prairies to a natural drought, and (3) test whether soil heterogeneity enhances resilience of restored prairie. We compared sensitivity and legacy effects between prairie types (remnant and restored) and among four prairie sites that included two remnant prairie sites and prairie restored under homogeneous and heterogeneous soil conditions. We measured sensitivity and resilience as the proportional change in aboveground net primary productivity (ANPP) during and following drought (sensitivity and legacy effects, respectively) relative to average ANPP based on 4 pre-drought years (2014-2017). In nondrought years, total ANPP was similar between remnant and restored prairie, but remnant prairie had higher grass productivity and lower forb productivity compared with restored prairie. These ANPP patterns generally persisted during drought. The sensitivity of total ANPP to drought was similar between restored and remnant prairie, but grasses in the restored prairie were more sensitive to drought. Post-drought legacy effects were more positive in the restored prairie, and we attributed this to the more positive and less variable legacy response of forb ANPP in the restored prairie, especially in the heterogeneous soil treatment. Our results suggest that productivity recovers in restored prairie and exhibits similar sensitivity to drought as in remnant prairie. Furthermore, creating heterogeneity promotes forb productivity and enhances restored prairie resilience to drought.
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Affiliation(s)
- Ashley A Wojciechowski
- Kansas Biological Survey & Center for Ecological Research and Department of Ecology & Evolutionary Biology, University of Kansas, Lawrence, Kansas, USA
| | - John M Blair
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
| | - Scott L Collins
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Sara G Baer
- Kansas Biological Survey & Center for Ecological Research and Department of Ecology & Evolutionary Biology, University of Kansas, Lawrence, Kansas, USA
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5
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Hu G, Bai H, Zhao Y, Chen N, Li H, Mao H, Guo Z, Sheng X, Zhang H, An H, Zhang P, Zhang Z, Sun Y, Ma M. Plant-Soil Moisture Positive Feedback Maintaining Alternative Stable States in the Alpine Marsh Ecosystem. Ecol Lett 2024; 27:e14508. [PMID: 39354903 DOI: 10.1111/ele.14508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 08/21/2024] [Accepted: 08/23/2024] [Indexed: 10/03/2024]
Abstract
A self-reinforcing positive feedback is regarded as a critical process for maintaining alternative stable states (ASS); however, identification of ASS and quantification of positive feedbacks remain elusive in natural ecosystems. Here, we used large-scale field surveys to search for ASS and a positive feedback mechanism under a wide range of habitats on the Tibetan Plateau. Using multiple methods, we proved that three stable states exist that accompany alpine marsh degradation. Positive feedbacks between changing soil moisture and plant community composition forced the ecosystem into another stable state, and the alteration of water use efficiency (WUE) of the component species contributed to this shift. This study provides the first empirical evidence that positive feedback loops maintain ASS in the alpine marsh ecosystem on the Tibetan Plateau. Our research revealed the powerful driving role of plants in transitions between states, which may support the conservation and restoration of global alpine marsh ecosystems.
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Affiliation(s)
- Guorui Hu
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, Gansu Province, People's Republic of China
| | - Haonan Bai
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, Gansu Province, People's Republic of China
| | - Yunpeng Zhao
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, Gansu Province, People's Republic of China
| | - Ning Chen
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, Gansu Province, People's Republic of China
| | - Honglin Li
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, Qinghai Province, People's Republic of China
| | - He Mao
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, Gansu Province, People's Republic of China
| | - Zengpeng Guo
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, Gansu Province, People's Republic of China
| | - Xiongjie Sheng
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, Gansu Province, People's Republic of China
| | - Hui Zhang
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, Gansu Province, People's Republic of China
| | - Hang An
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, Gansu Province, People's Republic of China
| | - Panhong Zhang
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, Gansu Province, People's Republic of China
| | - Zhengkuan Zhang
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, Gansu Province, People's Republic of China
| | - Yinguang Sun
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, Gansu Province, People's Republic of China
| | - Miaojun Ma
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, Gansu Province, People's Republic of China
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6
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Silber KM, Hefley TJ, Castro-Miller HN, Ratajczak Z, Boyle WA. The long shadow of woody encroachment: An integrated approach to modeling grassland songbird habitat. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2024; 34:e2954. [PMID: 38379458 DOI: 10.1002/eap.2954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 10/18/2023] [Accepted: 12/20/2023] [Indexed: 02/22/2024]
Abstract
Animals must track resources over relatively fine spatial and temporal scales, particularly in disturbance-mediated systems like grasslands. Grassland birds respond to habitat heterogeneity by dispersing among sites within and between years, yet we know little about how they make post-dispersal settlement decisions. Many methods exist to quantify the resource selection of mobile taxa, but the habitat data used in these models are frequently not collected at the same location or time that individuals were present. This spatiotemporal misalignment may lead to incorrect interpretations and adverse conservation outcomes, particularly in dynamic systems. To investigate the extent to which spatially and temporally dynamic vegetation conditions and topography drive grassland bird settlement decisions, we integrated multiple data sources from our study site to predict slope, vegetation height, and multiple metrics of vegetation cover at any point in space and time within the temporal and spatial scope of our study. We paired these predictions with avian mark-resight data for 8 years at the Konza Prairie Biological Station in NE Kansas to evaluate territory selection for Grasshopper Sparrows (Ammodramus savannarum), Dickcissels (Spiza americana), and Eastern Meadowlarks (Sturnella magna). Each species selected different types and amounts of herbaceous vegetation cover, but all three species preferred relatively flat areas with less than 6% shrub cover and less than 1% tree cover. We evaluated several scenarios of woody vegetation removal and found that, with a targeted approach, the simulated removal of just one isolated tree in the uplands created up to 14 ha of grassland bird habitat. This study supports growing evidence that small amounts of woody encroachment can fragment landscapes, augmenting conservation threats to grassland systems. Conversely, these results demonstrate that drastic increases in bird habitat area could be achieved through relatively efficient management interventions. The results and approaches reported pave the way for more efficient conservation efforts in grasslands and other systems through spatiotemporal alignment of habitat with animal behaviors and simulated impacts of management interventions.
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Affiliation(s)
- Katy M Silber
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
| | - Trevor J Hefley
- Department of Statistics, Kansas State University, Manhattan, Kansas, USA
| | | | - Zak Ratajczak
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
| | - W Alice Boyle
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
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7
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Keen RM, Bachle S, Bartmess M, Nippert JB. Combined effects of fire and drought are not sufficient to slow shrub encroachment in tallgrass prairie. Oecologia 2024; 204:727-742. [PMID: 38492034 DOI: 10.1007/s00442-024-05526-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 02/03/2024] [Indexed: 03/18/2024]
Abstract
Woody encroachment-the spread of woody vegetation in open ecosystems-is a common threat to grasslands worldwide. Reversing encroachment can be exceedingly difficult once shrubs become established, particularly clonal species that resprout following disturbance. Single stressors are unlikely to reverse woody encroachment, but using multiple stressors in tandem could be successful in slowing or reversing encroachment. We explored whether increasing fire frequency in conjunction with multi-year drought could reduce growth and survival of encroaching shrubs in a tallgrass prairie in northeastern Kansas, USA. Passive rainout shelters (~ 50% rainfall reduction) were constructed over mature clonal shrubs (Cornus drummondii) and co-existing C4 grasses in two fire treatments (1-year and 4-year burn frequency). Leaf- and whole-plant level physiological responses to drought and fire frequency were monitored in shrubs and grasses from 2019 to 2022. Shrub biomass and stem density following fire were unaffected by five years of consecutive drought treatment, regardless of fire frequency. The drought treatment had more negative effects on grass leaf water potential and photosynthetic rates compared to shrubs. Shrub photosynthetic rates were remarkably stable across each growing season. Overall, we found that five consecutive years of moderate drought in combination with fire was not sufficient to reduce biomass production or stem density in an encroaching clonal shrub (C. drummondii). These results suggest that moderate but chronic press-drought events do not sufficiently stress encroaching clonal shrubs to negatively impact their resilience following fire events, even when fire frequency is high.
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Affiliation(s)
- R M Keen
- Division of Biology, Kansas State University, Manhattan, KS, USA.
| | - S Bachle
- Division of Biology, Kansas State University, Manhattan, KS, USA
- LI-COR Biosciences, Lincoln, NE, 68504, USA
| | - M Bartmess
- United States Department of Agriculture, Natural Resource Conservation Service, Pottawatomie County, KS, USA
| | - J B Nippert
- Division of Biology, Kansas State University, Manhattan, KS, USA
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8
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Wilcox KR, Chen A, Avolio ML, Butler EE, Collins S, Fisher R, Keenan T, Kiang NY, Knapp AK, Koerner SE, Kueppers L, Liang G, Lieungh E, Loik M, Luo Y, Poulter B, Reich P, Renwick K, Smith MD, Walker A, Weng E, Komatsu KJ. Accounting for herbaceous communities in process-based models will advance our understanding of "grassy" ecosystems. GLOBAL CHANGE BIOLOGY 2023; 29:6453-6477. [PMID: 37814910 DOI: 10.1111/gcb.16950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 06/01/2023] [Indexed: 10/11/2023]
Abstract
Grassland and other herbaceous communities cover significant portions of Earth's terrestrial surface and provide many critical services, such as carbon sequestration, wildlife habitat, and food production. Forecasts of global change impacts on these services will require predictive tools, such as process-based dynamic vegetation models. Yet, model representation of herbaceous communities and ecosystems lags substantially behind that of tree communities and forests. The limited representation of herbaceous communities within models arises from two important knowledge gaps: first, our empirical understanding of the principles governing herbaceous vegetation dynamics is either incomplete or does not provide mechanistic information necessary to drive herbaceous community processes with models; second, current model structure and parameterization of grass and other herbaceous plant functional types limits the ability of models to predict outcomes of competition and growth for herbaceous vegetation. In this review, we provide direction for addressing these gaps by: (1) presenting a brief history of how vegetation dynamics have been developed and incorporated into earth system models, (2) reporting on a model simulation activity to evaluate current model capability to represent herbaceous vegetation dynamics and ecosystem function, and (3) detailing several ecological properties and phenomena that should be a focus for both empiricists and modelers to improve representation of herbaceous vegetation in models. Together, empiricists and modelers can improve representation of herbaceous ecosystem processes within models. In so doing, we will greatly enhance our ability to forecast future states of the earth system, which is of high importance given the rapid rate of environmental change on our planet.
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Affiliation(s)
- Kevin R Wilcox
- University of North Carolina Greensboro, Greensboro, North Carolina, USA
- University of Wyoming, Laramie, Wyoming, USA
| | - Anping Chen
- Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, USA
| | - Meghan L Avolio
- Earth and Planetary Sciences, Johns Hopkins University, Baltimore, Maryland, USA
| | - Ethan E Butler
- Department of Forest Resources, University of Minnesota, St. Paul, Minnesota, USA
| | - Scott Collins
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Rosie Fisher
- CICERO Centre for International Cimate Research, Forskningsparken, Oslo, Norway
| | - Trevor Keenan
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Nancy Y Kiang
- NASA Goddard Institute for Space Studies, New York, New York, USA
| | - Alan K Knapp
- Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, USA
| | - Sally E Koerner
- University of North Carolina Greensboro, Greensboro, North Carolina, USA
| | - Lara Kueppers
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Guopeng Liang
- Department of Forest Resources, University of Minnesota, St. Paul, Minnesota, USA
| | - Eva Lieungh
- Natural History Museum, University of Oslo, Oslo, Norway
| | - Michael Loik
- Department of Environmental Studies, University of California, Santa Cruz, California, USA
| | - Yiqi Luo
- School of Integrative Plant Science, Cornell University, Ithaca, New York, USA
| | - Ben Poulter
- Biospheric Sciences Lab, NASA GSFC, Greenbelt, Maryland, USA
| | - Peter Reich
- Department of Forest Resources, University of Minnesota, St. Paul, Minnesota, USA
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, Australia
| | | | - Melinda D Smith
- Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, USA
| | - Anthony Walker
- Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Ensheng Weng
- NASA Goddard Institute for Space Studies, New York, New York, USA
- Center for Climate Systems Research, Columbia University, New York, New York, USA
| | - Kimberly J Komatsu
- University of North Carolina Greensboro, Greensboro, North Carolina, USA
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9
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Wipulasena AYAP, Davison J, Helm A, Kasari L, Moora M, Prangel E, Reitalu T, Vahter T, Vasar M, Zobel M. Soil community composition in dynamic stages of semi-natural calcareous grassland. PLoS One 2023; 18:e0292425. [PMID: 37847721 PMCID: PMC10581465 DOI: 10.1371/journal.pone.0292425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 09/20/2023] [Indexed: 10/19/2023] Open
Abstract
European dry thin-soil calcareous grasslands (alvars) are species-rich semi-natural habitats. Cessation of traditional management, such as mowing and grazing, leads to shrub and tree encroachment and the local extinction of characteristic alvar species. While soil microbes are known to play a critical role in driving vegetation and ecosystem dynamics, more information is needed about their composition and function in grasslands of different dynamic stages. Here we assess the composition of soil fungal, prokaryotic, and plant communities using soil environmental DNA from restored alvar grasslands in Estonia. The study areas included grasslands that had experienced different degrees of woody encroachment prior to restoration (woody plant removal and grazing), as well as unmanaged open grasslands. We found that, in general, different taxonomic groups exhibited correlated patterns of between-community variation. Previous forest sites, which had prior to restoration experienced a high degree of woody encroachment by ectomycorrhizal Scots pine, were compositionally most distinct from managed open grasslands, which had little woody vegetation even prior to restoration. The functional structure of plant and fungal communities varied in ways that were consistent with the representation of mycorrhizal types in the ecosystems prior to restoration. Compositional differences between managed and unmanaged open grasslands reflecting the implementation of grazing without further management interventions were clearer among fungal, and to an extent prokaryotic, communities than among plant communities. While previous studies have shown that during woody encroachment of alvar grassland, plant communities change first and fungal communities follow, our DNA-based results suggest that microbial communities reacted faster than plant communities during the restoration of grazing management in alvar grassland. We conclude that while the plant community responds faster to cessation of management, the fungal community responds faster to restoration of management. This may indicate hysteresis, where the eventual pathway back to the original state (grazed ecosystem) differs from the pathway taken towards the alternative state (abandoned semi-natural grassland ecosystem).
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Affiliation(s)
- A. Y. Ayesh Piyara Wipulasena
- Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Tartu, Estonia
| | - John Davison
- Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Tartu, Estonia
| | - Aveliina Helm
- Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Tartu, Estonia
| | - Liis Kasari
- Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Tartu, Estonia
| | - Mari Moora
- Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Tartu, Estonia
| | - Elisabeth Prangel
- Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Tartu, Estonia
| | - Triin Reitalu
- Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Tartu, Estonia
| | - Tanel Vahter
- Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Tartu, Estonia
| | - Martti Vasar
- Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Tartu, Estonia
| | - Martin Zobel
- Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Tartu, Estonia
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10
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Dodds WK, Ratajczak Z, Keen RM, Nippert JB, Grudzinski B, Veach A, Taylor JH, Kuhl A. Trajectories and state changes of a grassland stream and riparian zone after a decade of woody vegetation removal. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2023; 33:e2830. [PMID: 36861408 DOI: 10.1002/eap.2830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/28/2022] [Accepted: 01/25/2023] [Indexed: 06/02/2023]
Abstract
Riparian zones and the streams they border provide vital habitat for organisms, water quality protection, and other important ecosystem services. These areas are under pressure from local (land use/land cover change) to global (climate change) processes. Woody vegetation is expanding in grassland riparian zones worldwide. Here we report on a decade-long watershed-scale mechanical removal of woody riparian vegetation along 4.5 km of stream channel in a before-after control impact experiment. Prior to this removal, woody plants had expanded into grassy riparian areas, associated with a decline in streamflow, loss of grassy plant species, and other ecosystem-scale impacts. We confirmed some expected responses, including rapid increases in stream nutrients and sediments, disappearance of stream mosses, and decreased organic inputs to streams via riparian leaves. We were surprised that nutrient and sediment increases were transient for 3 years, that there was no recovery of stream discharge, and that areas with woody removal did not shift back to a grassland state, even when reseeded with grassland species. Rapid expansion of shrubs (Cornus drummondii, Prunus americana) in the areas where trees were removed allowed woody vegetation to remain dominant despite repeating the cutting every 2 years. Our results suggest woody expansion can fundamentally alter terrestrial and aquatic habitat connections in grasslands, resulting in inexorable movement toward a new ecosystem state. Human pressures, such as climate change, atmospheric CO2 increases, and elevated atmospheric nitrogen deposition, could continue to push the ecosystem along a trajectory that is difficult to change. Our results suggest that predicting relationships between riparian zones and the streams they border could be difficult in the face of global change in all biomes, even in well-studied sites.
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Affiliation(s)
- Walter K Dodds
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
| | - Zak Ratajczak
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
| | - Rachel M Keen
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
| | - Jesse B Nippert
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
| | | | - Allison Veach
- Department of Integrative Biology, University of Texas at San Antonio, San Antonio, Texas, USA
| | - Jeffery H Taylor
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
| | - Amanda Kuhl
- Division of Biology, Kansas State University, Manhattan, Kansas, USA
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11
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Yang X, Xiao X, Zhang C. Spatiotemporal variability and key factors of evergreen forest encroachment in the southern Great Plains. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 329:117012. [PMID: 36608618 DOI: 10.1016/j.jenvman.2022.117012] [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: 04/06/2022] [Revised: 10/30/2022] [Accepted: 12/08/2022] [Indexed: 06/17/2023]
Abstract
Woody plant encroachment has been long observed in the southern Great Plains (SGP) of the United States. However, our understanding of its spatiotemporal variability, which is the basis for informed and targeted management strategy, is still poor. This study investigates the encroachment of evergreen forest, which is the most important encroachment component in the SGP. A validated evergreen forest map of the SGP (30 m resolution, for the time period 2015 to 2017) from our previous study was utilized (referred to as evergreen_base). Sample plots of evergreen forest (as of 2017) were collected across the study area, based on which a threshold of winter season (January and February) mean normalized difference vegetation index (NDVIwinter) was derived for each of the 5 sub-regions, using Landsat 7 surface reflectance data from 2015 to 2017. Then a NDVIwinter layer was created for each year within the four time periods of 1985-1989, 1995-1999, 2005-2009, and 2015-2017, with winter season surface reflectance data from Landsat 4, 5, and 7. By applying the sub-region specific NDVIwinter thresholds to the annual NDVIwinter layers and the evergreen_base, a SGP evergreen forest map was generated for each of those years. The annual evergreen forest maps within each time period were composited into one. According to the resulting four composite evergreen forest maps, mean annual encroachment rate (km2/year) was calculated at sub-region and ecoregion scales, over each of the three temporal stages 1990-1999, 2000-2009, and 2010-2017, respectively. To understand the spatiotemporal variability of the encroachment, the encroachment rate at each temporal stage was related to the corresponding initial evergreen forest area, mean annual precipitation (MAP), and mean annual burned area (MABA) through linear regression and pairwise comparison. Results suggest that most of the ecoregions have seen a slowing trend of evergreen forest encroachment since 1990. The temporal trend of encroachment rate tends to be consistent with that of MAP, but opposite to that of MABA. The spatial variability of the encroachment rate among ecoregions can be largely (>68%) explained by initial evergreen forest area but shows no significant relationship with MAP or MABA. These findings provide pertinent guidance for the combat of woody plant encroachment in the SGP under the context of climate change.
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Affiliation(s)
- Xuebin Yang
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, 73019, USA; Department of Geography and the Environment, Syracuse University, Syracuse, NY, 13244, USA.
| | - Xiangming Xiao
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, 73019, USA
| | - Chenchen Zhang
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, 73019, USA
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12
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Strydom T, Smit IPJ, Govender N, Coetsee C, Singh J, Davies AB, van Wilgen BW. High‐intensity fires may have limited medium‐term effectiveness for reversing woody plant encroachment in an African savanna. J Appl Ecol 2023. [DOI: 10.1111/1365-2664.14362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Affiliation(s)
- Tercia Strydom
- Scientific Services, South African National Parks Skukuza South Africa
| | - Izak P. J. Smit
- Scientific Services, South African National Parks Skukuza South Africa
- Sustainability Research Unit Nelson Mandela University George South Africa
| | - Navashni Govender
- Conservation Management, South African National Parks Skukuza South Africa
- School of Natural Resource Management Nelson Mandela University George South Africa
| | - Corli Coetsee
- Scientific Services, South African National Parks Skukuza South Africa
- School of Natural Resource Management Nelson Mandela University George South Africa
| | - Jenia Singh
- Department of Organismic and Evolutionary Biology Harvard University Cambridge Massachusetts USA
| | - Andrew B. Davies
- Department of Organismic and Evolutionary Biology Harvard University Cambridge Massachusetts USA
| | - Brian W. van Wilgen
- Department of Botany and Zoology, Centre for Invasion Biology Stellenbosch University Stellenbosch South Africa
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13
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Koerner SE, Avolio ML, Blair JM, Knapp AK, Smith MD. Multiple global change drivers show independent, not interactive effects: a long-term case study in tallgrass prairie. Oecologia 2023; 201:143-154. [PMID: 36507971 DOI: 10.1007/s00442-022-05295-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 11/27/2022] [Indexed: 12/15/2022]
Abstract
Ecosystems are faced with an onslaught of co-occurring global change drivers. While frequently studied independently, the effects of multiple global change drivers have the potential to be additive, antagonistic, or synergistic. Global warming, for example, may intensify the effects of more variable precipitation regimes with warmer temperatures increasing evapotranspiration and thereby amplifying the effect of already dry soils. Here, we present the long-term effects (11 years) of altered precipitation patterns (increased intra-annual variability in the growing season) and warming (1 °C year-round) on plant community composition and aboveground net primary productivity (ANPP), a key measure of ecosystem functioning in mesic tallgrass prairie. Based on past results, we expected that increased precipitation variability and warming would have additive effects on both community composition and ANPP. Increased precipitation variability altered plant community composition and increased richness, with no effect on ANPP. In contrast, warming decreased ANPP via reduction in grass stems and biomass but had no effect on the plant community. Contrary to expectations, across all measured variables, precipitation and warming treatments had no interactive effects. While treatment interactions did not occur, each treatment did individually impact a different component of the ecosystem (i.e., community vs. function). Thus, different aspects of the ecosystem may be sensitive to different global change drivers in mesic grassland ecosystems.
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Affiliation(s)
- Sally E Koerner
- Department of Biology, University of North Carolina Greensboro, Greensboro, NC, 27412, USA.
| | - Meghan L Avolio
- Department of Earth and Planetary Sciences, John Hopkins University, Baltimore, MD, 21218, USA
| | - John M Blair
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
| | - Alan K Knapp
- Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO, 80253, USA
| | - Melinda D Smith
- Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO, 80253, USA
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14
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Reintroducing bison results in long-running and resilient increases in grassland diversity. Proc Natl Acad Sci U S A 2022; 119:e2210433119. [PMID: 36037376 PMCID: PMC9457053 DOI: 10.1073/pnas.2210433119] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The widespread extirpation of megafauna may have destabilized ecosystems and altered biodiversity globally. Most megafauna extinctions occurred before the modern record, leaving it unclear how their loss impacts current biodiversity. We report the long-term effects of reintroducing plains bison (Bison bison) in a tallgrass prairie versus two land uses that commonly occur in many North American grasslands: 1) no grazing and 2) intensive growing-season grazing by domesticated cattle (Bos taurus). Compared to ungrazed areas, reintroducing bison increased native plant species richness by 103% at local scales (10 m2) and 86% at the catchment scale. Gains in richness continued for 29 y and were resilient to the most extreme drought in four decades. These gains are now among the largest recorded increases in species richness due to grazing in grasslands globally. Grazing by domestic cattle also increased native plant species richness, but by less than half as much as bison. This study indicates that some ecosystems maintain a latent potential for increased native plant species richness following the reintroduction of native herbivores, which was unmatched by domesticated grazers. Native-grazer gains in richness were resilient to an extreme drought, a pressure likely to become more common under future global environmental change.
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15
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Hudson AR, Peters DPC, Blair JM, Childers DL, Doran PT, Geil K, Gooseff M, Gross KL, Haddad NM, Pastore MA, Rudgers JA, Sala O, Seabloom EW, Shaver G. Cross-Site Comparisons of Dryland Ecosystem Response to Climate Change in the US Long-Term Ecological Research Network. Bioscience 2022; 72:889-907. [PMID: 36034512 PMCID: PMC9405733 DOI: 10.1093/biosci/biab134] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Long-term observations and experiments in diverse drylands reveal how ecosystems and services are responding to climate change. To develop generalities about climate change impacts at dryland sites, we compared broadscale patterns in climate and synthesized primary production responses among the eight terrestrial, nonforested sites of the United States Long-Term Ecological Research (US LTER) Network located in temperate (Southwest and Midwest) and polar (Arctic and Antarctic) regions. All sites experienced warming in recent decades, whereas drought varied regionally with multidecadal phases. Multiple years of wet or dry conditions had larger effects than single years on primary production. Droughts, floods, and wildfires altered resource availability and restructured plant communities, with greater impacts on primary production than warming alone. During severe regional droughts, air pollution from wildfire and dust events peaked. Studies at US LTER drylands over more than 40 years demonstrate reciprocal links and feedbacks among dryland ecosystems, climate-driven disturbance events, and climate change.
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Affiliation(s)
- Amy R Hudson
- Agricultural Research Service's Big Data Initiative and SCINet Program for Scientific Computing in Berwyn Heights , Maryland, United States
| | - Debra P C Peters
- Agricultural Research Service's Big Data Initiative and SCINet Program for Scientific Computing in Berwyn Heights , Maryland, United States
- US Department of Agriculture Agricultural Research Service's Jornada Experimental Range, Las Cruces , New Mexico, United States
- New Mexico State University , Las Cruces, New Mexico, United States
| | - John M Blair
- Kansas State University, Manhattan , Kansas, United States
| | | | - Peter T Doran
- Louisiana State University , Baton Rouge, Louisiana, United States
| | - Kerrie Geil
- Agricultural Research Service's Big Data Initiative and SCINet Program for Scientific Computing in Berwyn Heights , Maryland, United States
| | | | - Katherine L Gross
- W. K. Kellogg Biological Station, Vermont , United States
- Department of Plant Biology, Vermont , United States
| | - Nick M Haddad
- W. K. Kellogg Biological Station, Vermont , United States
- Department of Plant Biology, Vermont , United States
| | | | | | - Osvaldo Sala
- Arizona State University , Tempe, Arizona, United States
- Global Drylands Center and the School of Life Sciences, Arizona State University , Tempe, Arizona, United States
| | - Eric W Seabloom
- University of Minnesota , St. Paul, Minnesota, United States
| | - Gaius Shaver
- Marine Biological Laboratory, Woods Hole , Massachusetts, United States
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16
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Buisson E, Archibald S, Fidelis A, Suding KN. Ancient grasslands guide ambitious goals in grassland restoration. Science 2022; 377:594-598. [PMID: 35926035 DOI: 10.1126/science.abo4605] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Grasslands, which constitute almost 40% of the terrestrial biosphere, provide habitat for a great diversity of animals and plants and contribute to the livelihoods of more than 1 billion people worldwide. Whereas the destruction and degradation of grasslands can occur rapidly, recent work indicates that complete recovery of biodiversity and essential functions occurs slowly or not at all. Grassland restoration-interventions to speed or guide this recovery-has received less attention than restoration of forested ecosystems, often due to the prevailing assumption that grasslands are recently formed habitats that can reassemble quickly. Viewing grassland restoration as long-term assembly toward old-growth endpoints, with appreciation of feedbacks and threshold shifts, will be crucial for recognizing when and how restoration can guide recovery of this globally important ecosystem.
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Affiliation(s)
- Elise Buisson
- Institut Méditerranéen de Biodiversité et d'Ecologie, Avignon Université, CNRS, IRD, Aix Marseille Université, 84911 Avignon, France
| | - Sally Archibald
- Centre for African Ecology, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg 2050, South Africa
| | - Alessandra Fidelis
- Instituto de Biociências, Lab of Vegetation Ecology, Universidade Estadual Paulista (UNESP), Rio Claro 13506-900, Brazil
| | - Katharine N Suding
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA.,Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO, USA
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17
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Steketee JK, Rocha AV, Gough L, Griffin KL, Klupar I, An R, Williamson N, Rowe RJ. Small herbivores with big impacts: Tundra voles (Microtus oeconomus) alter post-fire ecosystem dynamics. Ecology 2022; 103:e3689. [PMID: 35324006 DOI: 10.1002/ecy.3689] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 10/14/2021] [Accepted: 10/28/2021] [Indexed: 11/11/2022]
Abstract
Fire is an important ecological disturbance that can reset ecosystems and initiate changes in plant community composition, ecosystem biogeochemistry, and primary productivity. Since herbivores rely on primary producers for food, changes in vegetation may alter plant-herbivore interactions with important - but often unexplored - feedbacks to ecosystems. Here we examined the impact of post-fire changes in plant community composition and structure on habitat suitability and rodent herbivore activity in response to a large, severe, and unprecedented fire in northern Alaskan tundra. In moist acidic tundra where the fire occurred, tundra voles (Microtus oeconomus) are the dominant herbivore and rely on the tussock forming sedge Eriophorum vaginatum for both food and nesting material. Seven to twelve years after the fire, tundra voles were 10 times more abundant at the burned site compared to nearby unburned tundra. Fire increased habitat suitability for voles by increasing plant productivity and biomass, food quality, and cover through both taller vegetation and increased microtopography. As a result of elevated vole abundance, Eriophorum mortality caused by vole herbivory was two orders of magnitude higher than natural mortality and approached the magnitude of the mortality rate resulting directly from the fire. These findings suggest that post-fire increases in herbivore pressure on Eriophorum could, in turn, disrupt graminoid recovery and enhance shrub encroachment. Tundra state transitions from graminoid to shrub dominated are also evident following other disturbances and fertilization experiments, suggesting that as Arctic temperatures rise, greater available nutrients and increased frequencies of large-scale disturbances may also alter plant-animal interactions with cascading impacts on plant communities and ecosystem function.
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Affiliation(s)
- Jess K Steketee
- Natural Resources and the Environment, University of New Hampshire, 114 James Hall, 56 College Road, Durham, NH, USA
| | - Adrian V Rocha
- Department of Biological Sciences and the Environmental Change Initiative, University of Notre Dame, Notre Dame, IN, USA
| | - Laura Gough
- Department of Biological Sciences, Towson University, Towson, Maryland, USA
| | - Kevin L Griffin
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY, USA.,Department of Earth and Environmental Sciences, Columbia University, Palisades, NY, USA.,Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA
| | - Ian Klupar
- Department of Biological Sciences and the Environmental Change Initiative, University of Notre Dame, Notre Dame, IN, USA
| | - Ruby An
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ
| | - Nicole Williamson
- Department of Biological Sciences, Towson University, Towson, Maryland, USA
| | - Rebecca J Rowe
- Natural Resources and the Environment, University of New Hampshire, 114 James Hall, 56 College Road, Durham, NH, USA
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18
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Li J, Ravi S, Wang G, Van Pelt RS, Gill TE, Sankey JB. Woody plant encroachment of grassland and the reversibility of shrub dominance: Erosion, fire, and feedback processes. Ecosphere 2022. [DOI: 10.1002/ecs2.3949] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Junran Li
- Department of Geosciences The University of Tulsa Tulsa Oklahoma USA
| | - Sujith Ravi
- Department of Earth and Environmental Science Temple University Philadelphia Pennsylvania USA
| | - Guan Wang
- Department of Geosciences The University of Tulsa Tulsa Oklahoma USA
| | - R. Scott Van Pelt
- Wind Erosion and Water Conservation Research USDA‐ARS Big Spring Texas USA
| | - Thomas E. Gill
- Department of Earth, Environmental and Resource Sciences and Environmental Science & Engineering Program University of Texas at El Paso El Paso Texas USA
| | - Joel B. Sankey
- Southwestern Biological Science Center, Grand Canyon Monitoring and Research Center U.S. Geological Survey Flagstaff Arizona USA
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19
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Ansley RJ, Moeller A, Fuhlendorf SD. Pyric‐based restoration of
C
4
grasses in woody (
Prosopis glandulosa
) encroached grassland is best with an alternating seasonal fire regime. Restor Ecol 2022. [DOI: 10.1111/rec.13644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- R. James Ansley
- Department of Natural Resource Ecology and Management Oklahoma State University Stillwater OK USA 74078
| | - Anna Moeller
- Department of Natural Resource Ecology and Management Oklahoma State University Stillwater OK USA 74078
| | - S. D. Fuhlendorf
- Department of Natural Resource Ecology and Management Oklahoma State University Stillwater OK USA 74078
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20
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OUP accepted manuscript. Bioscience 2022. [DOI: 10.1093/biosci/biac034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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21
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Mino L, Kolp MR, Fox S, Reazin C, Zeglin L, Jumpponen A. Watershed and fire severity are stronger determinants of soil chemistry and microbiomes than within-watershed woody encroachment in a tallgrass prairie system. FEMS Microbiol Ecol 2021; 97:6445025. [PMID: 34849770 DOI: 10.1093/femsec/fiab154] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 11/24/2021] [Indexed: 11/13/2022] Open
Abstract
Fire can impact terrestrial ecosystems by changing abiotic and biotic conditions. Short fire intervals maintain grasslands and communities adapted to frequent, low-severity fires. Shrub encroachment that follows longer fire intervals accumulates fuel and can increase fire severity. This patchily distributed biomass creates mosaics of burn severities in the landscape-pyrodiversity. Afforded by a scheduled burn of a watershed protected from fires for 27 years, we investigated effects of woody encroachment and burn severity on soil chemistry and soil-inhabiting bacteria and fungi. We compared soils before and after fire within the fire-protected, shrub-encroached watershed and soils in an adjacent, annually burned and non-encroached watershed. Organic matter and nutrients accumulated in the fire-protected watershed but responded less to woody encroachment within the encroached watershed. Bioavailable nitrogen and phosphorus and fungal and bacterial communities responded to high-severity burn regardless of encroachment. Low-severity fire effects on soil nutrients differed, increased bacterial but decreased fungal diversity and effects of woody encroachment within the encroached watershed were minimal. High-severity burns in the fire-protected watershed led to a novel soil system state distinct from non-encroached and encroached soil systems. We conclude that severe fires may open grassland restoration opportunities to manipulate soil chemistry and microbial communities in shrub-encroached habitats.
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Affiliation(s)
- Laura Mino
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Matthew R Kolp
- Department of Microbiology, University of Tennessee, 520B Ken and Blaire Mossman Bldg, 1311 Cumberland Ave, Knoxville, TN 37996, USA
| | - Sam Fox
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Chris Reazin
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Lydia Zeglin
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Ari Jumpponen
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
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22
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Bielski CH, Scholtz R, Donovan VM, Allen CR, Twidwell D. Overcoming an "irreversible" threshold: A 15-year fire experiment. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 291:112550. [PMID: 33965707 DOI: 10.1016/j.jenvman.2021.112550] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 03/30/2021] [Accepted: 04/03/2021] [Indexed: 06/12/2023]
Abstract
A key pursuit in contemporary ecology is to differentiate regime shifts that are truly irreversible from those that are hysteretic. Many ecological regime shifts have been labeled as irreversible without exploring the full range of variability in stabilizing feedbacks that have the potential to drive an ecological regime shift back towards a desirable ecological regime. Removing fire from grasslands can drive a regime shift to juniper woodlands that cannot be reversed using typical fire frequency and intensity thresholds, and has thus been considered irreversible. This study uses a unique, long-term experimental fire landscape co-dominated by grassland and closed-canopy juniper woodland to determine whether extreme fire can shift a juniper woodland regime back to grassland dominance using aboveground herbaceous biomass as an indicator of regime identity. We use a space-for-time substitute to quantify herbaceous biomass following extreme fire in juniper woodland up to 15 years post-fire and compare these with (i) 15 years of adjacent grassland recovery post-fire, (ii) unburned closed-canopy juniper woodland reference sites and (iii) unburned grassland reference sites. Our results show grassland dominance rapidly emerges following fires that operate above typical fire intensity thresholds, indicating that grassland-juniper woodlands regimes are hysteretic rather than irreversible. One year following fire, total herbaceous biomass in burned juniper stands was comparable to grasslands sites, having increased from 5 ± 3 g m-2 to 142 ± 42 g m-2 (+2785 ± 812 percent). Herbaceous dominance in juniper stands continued to persist 15-years after initial treatment, reaching a maximum of 337 ± 42 g m-2 eight years post-fire. In juniper encroached grasslands, fires that operate above typical fire intensity thresholds can provide an effective method to reverse juniper woodland regime shifts. This has major implications for regions where juniper encroachment threatens rancher-based economies and grassland biodiversity and provides an example of how to operationalize resilience theory to disentangle irreversible thresholds from hysteretic system behavior.
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Affiliation(s)
- Christine H Bielski
- Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE, 68503-0984, USA
| | - Rheinhardt Scholtz
- Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE, 68503-0984, USA
| | - Victoria M Donovan
- Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE, 68503-0984, USA
| | - Craig R Allen
- Center for Resilience in Agricultural Working Lands, University of Nebraska, Lincoln, NE, 68503-0984, USA
| | - Dirac Twidwell
- Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE, 68503-0984, USA.
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23
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Ma M, Collins SL, Ratajczak Z, Du G. Soil Seed Banks, Alternative Stable State Theory, and Ecosystem Resilience. Bioscience 2021. [DOI: 10.1093/biosci/biab011] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
In restoration ecology, the transition from desired to degraded state is based solely on the composition of the aboveground plant community, whereas belowground propagules are often neglected. We developed a conceptual framework integrating seed bank dynamics into alternative stable state theory, highlighting the important relationship between aboveground and belowground composition. This integration emphasizes the role of resilience in systems that appear to have shifted to an “undesirable” state. Belowground propagules, especially soil seed and bud banks, provide buffering capacity and may serve as valuable indicators of potential resistance to state transition based on the degree of similarity between belowground and aboveground vegetation composition. Ecosystem states may have multiple components that differ in their rate of change, as well as in their capacity to promote resilience. We recommend that the application of alternative stable state theory from a management perspective should incorporate components of both above- and belowground vegetation.
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Affiliation(s)
- Miaojun Ma
- State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, Gansu Province, China
| | - Scott L Collins
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, United States
| | - Zak Ratajczak
- Division of Biology, Kansas State University, Manhattan, Kansas, United States
| | - Guozhen Du
- State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, Gansu Province, China
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