Institute for Biodiversity, Ecology, Evolution, and Macrosystems
Michigan State University
Michigan State University
IBEEM Research Projects
Featured Research:
Mycorrhizal types and resource gradients: how do trait by environment interactions shape density-dependent demographic processes in hardwood forests?
Can conserved traits among tree species be used to predict seedling recruitment and mortality under global change? 2025 IBEEM Postdoctoral Fellows Andrew Eagar and Bailey McNichol are leveraging 25 years of data from 12 sites and 2400 plots in the Manistee National Forest, Michigan, representing >175,000 seedlings and 6800 adult trees, to answer this question. Their research aims to identify which trees, or groups of trees that share certain traits, are more vulnerable to changing environmental conditions and abiotic stressors.
Research Summary. Identifying generalizable trends in ecology is often complicated by inherent trait differences among individuals and species, which interact with environmental conditions to produce context-dependent outcomes. As a result, most studies of density-dependent mechanisms of mortality in forests are done at the species level. Typically, as a tree species becomes more locally abundant, the mortality rate of its recruited seedlings also increases. However, this is not universal. Some species can generate positive feedback with their soil environment, resulting in weaker or no negative effects of density on seedling survival.
Tree mycorrhizal associations – representing suites of integrative species traits related to resource acquisition strategies and growth-defense trade-offs – have been recently proposed as a simplified framework for examining these demographic processes across entire forested communities. Our team is testing whether arbuscular (AM) and ectomycorrhizal (ECM) trees exhibit consistent differences in seedling recruitment and mortality along resource gradients, depending on the dominant type of mycorrhizal association in the surrounding tree community. By focusing on community-level outcomes driven by complex, belowground interactions, we aim to develop a useful and accessible framework for assessing forest health and resilience under global change.
Research Summary. Identifying generalizable trends in ecology is often complicated by inherent trait differences among individuals and species, which interact with environmental conditions to produce context-dependent outcomes. As a result, most studies of density-dependent mechanisms of mortality in forests are done at the species level. Typically, as a tree species becomes more locally abundant, the mortality rate of its recruited seedlings also increases. However, this is not universal. Some species can generate positive feedback with their soil environment, resulting in weaker or no negative effects of density on seedling survival.
Tree mycorrhizal associations – representing suites of integrative species traits related to resource acquisition strategies and growth-defense trade-offs – have been recently proposed as a simplified framework for examining these demographic processes across entire forested communities. Our team is testing whether arbuscular (AM) and ectomycorrhizal (ECM) trees exhibit consistent differences in seedling recruitment and mortality along resource gradients, depending on the dominant type of mycorrhizal association in the surrounding tree community. By focusing on community-level outcomes driven by complex, belowground interactions, we aim to develop a useful and accessible framework for assessing forest health and resilience under global change.
Previous Research:
Global quantification of species competitive ability along resource gradients
How do species co-exist when the level of resources changes? A team of four IBEEM Postdoctoral Fellows – Alejandra Martínez Blancas, Laís Petri, Ashwini Ramesh, and Amar Deep Tiwari – are seeking to answer this question. Using systematic meta-analyses, their work aims to uncover insights into the influence of resources on competition and biodiversity which will contribute to our fundamental understanding of the factors shaping the structure of ecological communities. You can find a
A Summary of their Research
The maintenance of species diversity, especially in the face of species extinction via climate change has long been a central question in global biodiversity. Loss of species implies that climate change undermines mechanisms of species coexistence, threatening food webs and destabilizing ecosystem function. Thus, to best anticipate such harm, we need fundamental-level insight into mechanisms governing species coexistence in a changing world. One prominent mechanism centers on the role of resource gradients in facilitating species coexistence. Competition for resources is a process by which an individual of a species captures resources (e.g., minerals, light, or water) to limit its competitors. The outcome of competition across resource gradients, a classically studied community assembly mechanism, is a prominent factor promoting coexistence and, consequently, diversity. If resource competition is indeed fundamental to species coexistence, should there not be universal mechanisms governing these interactions across ecosystems? Despite resource competition serving as a fundamental principle governing species coexistence, a comprehensive understanding of resource-biodiversity relationships remain elusive. Here, we synthesize how species competition shifts across resource gradients in a changing world across multiple ecosystems. Our approach integrates food web theory, meta-analysis, data-fitting, and climate mapping to propose unifying community assembly rules in a changing world. Additionally, to contextualize the science and its representation, we quantify both geographical bias and the extent of parachute science serves as preliminary steps toward a more inclusive and equitable science.
Ramesh, A., Martínez-Blancas, A., Petri, L., Tiwari, A., Bills, P., & Zarnetske, P. L. Global quantification of species competitive ability along resource gradients. In prep.
Learn more in the project's Open Science Framework Repository.
A Summary of their Research
The maintenance of species diversity, especially in the face of species extinction via climate change has long been a central question in global biodiversity. Loss of species implies that climate change undermines mechanisms of species coexistence, threatening food webs and destabilizing ecosystem function. Thus, to best anticipate such harm, we need fundamental-level insight into mechanisms governing species coexistence in a changing world. One prominent mechanism centers on the role of resource gradients in facilitating species coexistence. Competition for resources is a process by which an individual of a species captures resources (e.g., minerals, light, or water) to limit its competitors. The outcome of competition across resource gradients, a classically studied community assembly mechanism, is a prominent factor promoting coexistence and, consequently, diversity. If resource competition is indeed fundamental to species coexistence, should there not be universal mechanisms governing these interactions across ecosystems? Despite resource competition serving as a fundamental principle governing species coexistence, a comprehensive understanding of resource-biodiversity relationships remain elusive. Here, we synthesize how species competition shifts across resource gradients in a changing world across multiple ecosystems. Our approach integrates food web theory, meta-analysis, data-fitting, and climate mapping to propose unifying community assembly rules in a changing world. Additionally, to contextualize the science and its representation, we quantify both geographical bias and the extent of parachute science serves as preliminary steps toward a more inclusive and equitable science.
Ramesh, A., Martínez-Blancas, A., Petri, L., Tiwari, A., Bills, P., & Zarnetske, P. L. Global quantification of species competitive ability along resource gradients. In prep.
Learn more in the project's Open Science Framework Repository.
Characterizing the role of environmental variability in structuring the life histories of global ecological communities
How do patterns of environmental variability within a year (i.e., seasons) and between years affect species' life histories? 2023 IBEEM Postdoctoral Fellows Casey Youngflesh, Kelly Kapsar, Adriana Uscanga, Peter Williams, Jeff Doser, and Lala Kounta set out to answer this question using data from open source biodiversity repositories. They looked at environmental variability within and between years across the range of over 7,000 non-migratory bird species to parse out impacts of variability on species' pace of life.
Summary of their Research
Theory suggests life history plays a key role in the ability of organisms to persist under fluctuating environmental conditions. However, this notion has gone largely untested using empirical data. Synthesizing a collection of data resources on global climate, species traits, and species ranges, we quantified the role that environmental variability over time has played in shaping pace of life across the world’s resident bird species (N = 7477). In support of existing theory, we found that species that experience high inter-annual temperature variability tended to have a slower pace of life, while the opposite was true for high intra-annual temperature variability (i.e. temperature seasonality). The effect of precipitation variability was less pronounced and more uncertain. These observed patterns were apparent despite the vastly different ecologies of our study species and evidence of strong phylogenetic constraint. Additionally, we highlight the importance of considering both environmental variability and pace of life when assessing how species will likely respond to environmental change. Rates of environmental change should be placed into a broader evolutionary context. Quantifying these interactions is key not only for understanding observed macroecological patterns but also for determining which species might be most susceptible to global change.
Youngflesh, C., Kapsar, K., Uscanga, A., Williams, P. J., Doser, J. W., Kounta, L., & Zarnetske, P. L.. Environmental variability shapes life history of the world's birds. In review.
Theory suggests life history plays a key role in the ability of organisms to persist under fluctuating environmental conditions. However, this notion has gone largely untested using empirical data. Synthesizing a collection of data resources on global climate, species traits, and species ranges, we quantified the role that environmental variability over time has played in shaping pace of life across the world’s resident bird species (N = 7477). In support of existing theory, we found that species that experience high inter-annual temperature variability tended to have a slower pace of life, while the opposite was true for high intra-annual temperature variability (i.e. temperature seasonality). The effect of precipitation variability was less pronounced and more uncertain. These observed patterns were apparent despite the vastly different ecologies of our study species and evidence of strong phylogenetic constraint. Additionally, we highlight the importance of considering both environmental variability and pace of life when assessing how species will likely respond to environmental change. Rates of environmental change should be placed into a broader evolutionary context. Quantifying these interactions is key not only for understanding observed macroecological patterns but also for determining which species might be most susceptible to global change.
Youngflesh, C., Kapsar, K., Uscanga, A., Williams, P. J., Doser, J. W., Kounta, L., & Zarnetske, P. L.. Environmental variability shapes life history of the world's birds. In review.
Click here to view current news and research from our affiliate program, MSU EEB.
Institute for Biodiversity, Ecology, Evolution, and Macrosystems
Michigan State University
East Lansing, MI 48824
[email protected]
Michigan State University
East Lansing, MI 48824
[email protected]