Colloque – Nouvelles approches pour le suivi des plantes, des pollinisateurs et de leurs interactions dans un monde en changement : Long-Term Changes in Forest Plant Communities Have Affected Species’ Abundances and Pollinator Resources

Emmanuelle PorcherCollège de FranceBiodiversité et écosystèmesAnnée 2023-2024Colloque - Nouvelles approches pour le suivi des plantes, des pollinisateurs et de leurs interactions dans un monde en changement : Long-Term Changes in Forest Plant Communities Have Affected Species' Abundances and Pollinator ResourcesDonald M. WallerAmerican datasets from forestREplot, Madison, USARésuméBaseline surveys are essential to assess long-term shifts in plant communities. In the early 2000s, we re-surveyed 293 sites of six forest types in Wisconsin, USA. Data from these sites, first surveyed in the 1950s, allowed us to infer long-term shifts in diversity and abundance of 292 species. Statewide, more species decreased in abundance (63%, and 68% of native species) than increased (37% of species, including most non-native species). Native species declined, on average, by 41% while non-native species increased by 584%. Many animal-pollinated wildflowers declined conspicuously, while abiotically pollinated graminoids and some ferns tended to increase. Among native species, those with zygomorphic flowers (specialized pollinators) declined more in abundance. Among non-native species, those with abiotic pollination showed smaller increases. Declines were greater in smaller, more fragmented southern upland forest patches, reflecting a continuing extinction debt. Small remnant grasslands experienced even higher species losses and stronger area effects. Larger, more continuous forests in northern Wisconsin retained plant diversity better but deer herbivory has shifted their composition. Understanding how diversity and traits shifted across sites and communities helps illuminate the mechanisms driving changes in diversity and pollinator resources in temperate forests.Donald M. WallerProf. Waller taught ecology, evolution, and conservation biology at the University of Wisconsin-Madison as the Curtis Professor of Botany & Environmental Studies. His interests include plant population dynamics; plant reproductive ecology; effects of habitat fragmentation; monitoring long-term ecological change to identify drivers (e.g., forestREplot); and how ungulates and N-deposition affect forest plant communities. He served as Associate Editor of Ecology Letters, Editor-in-Chief of Evolution, a Fellow of the American Association for the Advancement of Science, a Palme Academique recipient, and President of the Society for the Study of Evolution. He co-authored Wild Forests: Conservation Biology and Public Policy (Island Press) and edited The Vanishing Present: Shifts in Wisconsin's lands, waters, and wildlife (Univ. of Chicago Press). Dr Waller works to apply his expertise to improve forest, wildlife, and habitat management.