Collaborative research: making positive interactions mainstream: toward better integration of facilitation into freshwater science

The National Science Foundation Division of Environmental Biology awarded Northern Michigan University $236,015 on June 15, 2026, under the Biological Sciences program (CFDA 47.074) to conduct collaborative research on positive biotic interactions in freshwater ecosystems.

The project will quantify how abiotic context, functional traits, and spatio-temporal scale govern the outcome and strength of facilitation—a positive interaction in which one species modifies habitat to improve fitness of other species. Researchers will employ laboratory and field experiments, data synthesis, and modeling to generate AI-ready datasets of facilitation across freshwater species groups including fishes and insects, with the goal of testing the stress-gradient hypothesis across multiple dimensions in imperiled freshwater ecosystems. The work will produce cross-scale inference from continents to streambeds and advance understanding of positive interactions that could increase productivity and yields in fisheries and aquaculture. Research trainees will develop skills in artificial intelligence applications including data synthesis, data visualization, and programming. Public outreach will disseminate findings through videos and educational lesson plans.

Performance occurs in Marquette, Michigan, with an ultimate completion date of May 31, 2029.

Abstract

To understand how species interactions influence ecological communities, this project confronts key sources of context dependency in facilitation research. Facilitation is a type of positive biotic interaction in which one species (a facilitator) modifies habitat that improves fitness of other species (beneficiaries). The stress-gradient hypothesis (SGH) predicts that the role of facilitators for structuring ecological communities should become increasingly important as environmental conditions become increasingly harsh. This project will identify how three important factors related to stress gradients govern the outcome and strength of positive interactions: abiotic context, functional traits, and spatio-temporal scale (CTS). The research will quantify how CTS factors interact with one another to determine the strength of positive interactions and will enhance facilitation theory by interrogating the SGH across CTS dimensions in imperiled freshwater ecosystems. Public outreach will highlight the importance and breadth of positive interactions in freshwaters through videos and educational lesson plans. Research trainees will develop and grow their skills in artificial intelligence (AI) applications, including data synthesis, data visualization, and programming languages. The advances that the project will make to science and biotechnology fill critical knowledge gaps by revealing roles of positive interactions that could increase productivity and yields of fisheries and aquaculture. Specifically, researchers will use laboratory and field experiments, data synthesis, and modelling to produce large, AI-ready datasets of facilitation across freshwater species groups and types, including fishes and insects. This work will provide cross-scale inference from continents to streambeds by making four convergent contributions: (a) uniting disparate, but well-studied evidence to refine foundational ecological theory on species interactions; (b) developing an invigorated conceptual framework revolving around CTS factors for advancing facilitation research; (c) providing more robust tools for addressing the role of species and their interactions in a sensitive ecosystem (freshwater) that is both disproportionally imperiled and grossly understudied; and (d) providing open-access data products. Researchers will use a coordinated experiment at multiple locations across the US to quantify how traits of aquatic insects and environmental context interact to influence facilitation dynamics. To examine how abiotic context influences spatial scaling of interaction dynamics between facilitator and beneficiary, they will then use fish assemblage models across thousands of north american streams. Finally, this project will use meta-analytic approaches to synthesize positive interaction relationships between traits and scale across species around the globe by quantifying components of facilitation legacies. The results from these studies will identify new considerations of facilitation, including mutualisms and symbiosis, that advance our understanding of species interactions. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the foundation's intellectual merit and broader impacts review criteria.- subawards are not planned for this award.