Use of short-rotation coppice willow crops by birds and small mammals in central New York

As the use of short-rotation coppice willow crops increases, this vegetation type will comprise a greater extent of the landscape, yet its attendant effects on biodiversity remain poorly understood. In this study we characterized the avian and small mammal communities of willow crops that were established for phytoremediation and biomass production in industrial settling basins and compared these communities to those of surrounding areas of naturally-established perennial herbaceous-woody vegetation. Overall, we observed 33 bird species and five small mammal species in five focal sites (i.e., areas consisting of willow crops and adjacent vegetation) and 20 bird species and four small mammal species in two reference sites (i.e., areas of the settling basins without willow crops). For birds and small mammals, focal sites supported slightly greater average species richness and average abundances of all species combined than reference sites. Within focal sites, willow crops supported fewer species and similar combined abundances compared to adjacent areas. Importantly, community and individual species responses varied with the duration of time since coppicing. More small mammal species and individuals used willow crops in the year following coppicing because of their herbaceous undergrowth, while more birds tended to use older willow crops. Collectively, these results indicate that willow crops located within areas of perennial herbaceous-woody vegetation provide some benefits to bird and small mammal populations and that promoting a herbaceous layer in willow crops and maintaining multiple age classes of willows in the landscape simultaneously are likely to enhance the value of willow crops for biodiversity.

► Willow crops were planted among areas of perennial herbaceous-woody vegetation.
► Willow crops increased bird and small mammal abundances of these areas.
► Fewer bird and small mammal species were found in willow crops than adjacent areas.
►  A herbaceous layer within willow crops enhanced small mammal richness and abundance.
► Responses of birds and small mammals varied with the age of the willow crops.