Research themes

Coexistence and stability in altered environments

For species to persist over time, population growth must be frequency dependent. Natural communities encompass a wide range of mechanisms that generate frequency dependence, including resource partitioning and differential vulnerability to predators. Collectively, these processes are referred to as stabilizing mechanisms, as they increase so-called niche differences.

We are also interested in linking this new measure to other aspects of system stability, including resilience (i.e., local stability) and robustness (the propensity for secondary extinctions).

Multivariate environmental change

Global change is multifaceted. Understanding and predicting its effects on ecological systems is both a central scientific challenge and an urgent societal need. At present, however, mechanistic theory for studying long-term ecological change—encompassing community composition, biodiversity, and stability—remains limited.

We address this gap by developing new theory aimed at fostering a general, system-independent understanding of ecological change. Our framework predicts ecological responses to multivariate environmental change using an ensemble of generic descriptors, including community ecological structure, the dynamics of multiple environmental drivers, species’ direct responses to these drivers, and their adaptive potential. This approach enables the identification of general patterns and key differences among types of communities and environmental changes, thereby facilitating synthesis.

Eco-evolutionary feedbacks and stability

The structure of biological systems is an important determinant of many stability properties. However, complex eco-evolutionary dynamics can alter system responses to perturbations in ways that cannot be predicted from structure alone. Specifically, perturbations trigger direct biological responses that propagate through phenotype-mediated ecological interactions to shape system-level dynamics. Both these direct responses and the resulting interactions depend on phenotypic variance, which itself can evolve as a consequence of those same responses and interactions.

How such feedbacks influence stability beyond resilience in systems with stable equilibria remains poorly understood. We develop theory to investigate how eco-evolutionary feedbacks contribute to a broader range of stability properties.

Implications of biodiversity change for function

Human activities are driving global environmental change with profound consequences for ecosystem functioning. Understanding these consequences is essential for informing effective policy and conservation strategies. A central question is the extent to which changes in ecosystem functioning are mediated by changes in biodiversity. Extensive research has shown that biodiversity underpins the stable provision and enhancement of ecosystem processes and functions.

However, classic experiments linking biodiversity to ecosystem functioning may not fully capture the complex pathways through which global change–induced shifts in biodiversity affect ecosystem functioning. We therefore develop models to understand and simulate the impacts of environmental change on ecosystem functions such as biomass production and litter decomposition.