Concurrent Session: Wetland wildlife
9:30 AM - 10:30 AM Thu
Co-authors: Hannah Rammage, Lake Superior National Estuarine Research Reserve; Anna Pidgeon, UW-Madison
Title: Assessing avian abundance and richness in structurally diverse black ash wetlands
Abstract: Black ash (Fraxinus nigra Marsh.) is a foundational wetland species affecting ecosystem structure. The spread of the non-native emerald ash borer (Agrilus planipennis, EAB) threatens the St. Louis River estuary, which contains large intact black ash stands. We quantified the structural habitat features of black ash stands and explored their relationship to avian richness and abundance. I conducted avian point count surveys and measured vegetation at 12 sites along the estuary corridor. I analyzed relationships between avian metrics and forest structural features using Spearman and Pearson correlations and non-metric multidimensional scaling ordination. I found strong variation in black ash stand forest structure among sites. Even sites within close proximity had differences in understory density (stem count range 0-736, SD=209) and canopy height (7.85-19.1 meters, SD=3.2). The avian community also varied among sites (22-43 individuals/site, 14-24 sp/site). Avian richness was most strongly correlated with black ash dominance that ranged from 60-91% (Pearson correlation; r=0.55, p<0.1). Red-eyed vireo, least flycatcher, and yellow warbler were well-associated and found in higher abundances in mature forests with low understory density. These species are only associated with black ash and could lose this habitat to invasive shrubs when ash mortality occurs. To mitigate conversion to invasive shrub species dominance, the Lake Superior National Estuarine Research Reserve and Minnesota Land Trust plan to steward St. Louis estuary wetland forests by planting replacement tree species before ash die off. The results of this study will help them determine the appropriate tree species and shape future monitoring and research.
Bio: Cole Wilson is a senior at UW-Madison studying wildlife ecology. Over the past year, he has worked as a freshwater fellow for the Lake Superior National Estuarine Research Reserve in Superior, Wisconsin. As a child growing up in Milwaukee, he gained a special appreciation for ecology (and birds in particular) while spending time in the city’s wonderful parks!