Bird Diversity and Prairie Restoration
Background
Tallgrass prairie used to cover the majority of Minnesota’s landscape, but due to agriculture and urbanization, prairie landscapes have been altered or heavily fragmented. Consequently, birds that thrive in tallgrass prairies have also suffered. Many land restoration initiatives in Minnesota are focused on prairie regrowth. Research has shown that restored prairies are most healthy and successful when maximizing the size of the prairie, rather than managing small fragments of land.
Ecotones are borders between one habitat and another. For example, an ecotone could be the edge between a prairie and a forest or a wetland. Studies have shown that they tend to have high biodiversity and high species richness compared to the habitats they border. Birds make an excellent indicator species (a species which can show the relative health of an ecosystem). By monitoring birds along various ecotones and their adjacent habitats, one can learn about the health of the area.
A St. Olaf student in 2020 sought out to monitor the species composition of birds along ecotones in the Natural Lands and compare the data to data taken from pure prairie habitats in order to understand how ecotones may be affecting tallgrass prairie restoration and supporting bird communities.
The Study
Gunnar Bodvarsson (Class of 2022, B.A. Biology) chose four sites to study in the Natural Lands. Big Pond was noted as a prairie-wetland ecotone, Coyote Pond East was designated a prairie-oak savanna ecotone, and Northwest Prairie and Dragonfly Pond were exclusively prairie habitats.
Bodvarsson used binoculars and a DSLR camera to photograph, identify, and count birds at these sites during September and October. The results were analyzed for species diversity and changes over time.
The Findings
Bodvarsson found that Big Pond and Coyote Pond East (ecotone sites) had the greatest diversity compared to the other two sites. The birds at these sites represented not only prairie-reliant species, but forest and wetland habitat species as well. The results supported the previous studies that have suggested that ecotones tend to be more diverse than their adjacent habitats.
The species composition data showed that the birds that occupy prairie habitat in the Natural Lands are representative of birds that historically have occupied tallgrass prairies, like American goldfinches and yellow rumped warblers, though ecotones are also supporting non-prairie-reliant species as well, like waterfowl and song sparrows. Bodvarsson concluded that the data were collected in an effort to provide more information about the health of the ecosystems in the Natural Lands, and based on their data can indicate successful prairie restoration initiatives thus far.
Relevance
The Natural Lands is always working toward collecting data that can help managers better understand the needs of the land and health of wildlife and vegetation. Bodvarsson’s research, along with other data collected about bird communities in prairies will continue to inform the Natural Lands’ approach to restoration.
Citation
Bodvarsson, G. 2020.Bird community composition and diversity in tallgrass prairie and a bordering prairie-forest ecotone as summer transitions to autumn in southeast Minnesota. St. Olaf College Local Ecology Papers.