Habitat Selection by Birds in Willow-Ringed Wetlands: Management Implications for Harvesting Willow Biomass
Mushanski, Melissa Dawn
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Increase in prices of fossil fuels and escalating environmental conflicts have generated renewed interest in bioenergy production. Abundant small wetlands ringed with willow species (willow rings) growing naturally in the Prairie Ecozone of North America may provide a source of natural biomass as a bioenergy feedstock. Subsequently, a bioenergy crop from these wetlands could increase their economic value and help reduce their drainage and loss. Little is known about the importance of willow vegetation to birds, and what habitat features may be important to consider when planning biomass harvest. To address this knowledge gap, I conducted point count surveys in the spring of 2012 and 2013 at 92 willow rings in south-eastern Saskatchewan. My objectives were to determine: 1) what species make up the willow- ring bird community; 2) what wetland and vegetation characteristics influence bird abundance; and 3) whether abundance of willow-ringed wetland birds varies as a function of the surrounding upland habitat (cropland vs. grassland). I found that the willow ring community is composed of at least 66 species from 3 distinct guilds: woodland, wetland, and grassland birds, and that members of each guild responded differently to willow ring structure and habitat features. For example, American robin (Turdus migratorius) and yellow warbler (Setophaga petechia), both woodland species, increased in abundance as willow area increased. A wetland bird species, the American coot (Fulica americana), decreased in abundance as % willow cover increased. However, all other species were unaffected by changes in the willow ring structure, suggesting that willow harvest will have little impact on these birds. Woodland bird species may decrease as their habitat is lost; however, management practices such as partial harvests or rotational harvest by year may make willow harvest sustainable for all species. Furthermore, land managers should adjust harvest guidelines to reflect local bird management objectives. In doing so, willow harvest can likely be done with minimal impact on bird species associated with willow-ringed wetlands.