Abstract
Powerline rights-of-way (ROWs) often provide habitat for early successional bird species that have suffered long-term population declines in eastern North America. To determine how the abundance of shrubland birds varies with habitat within ROW corridors and with land use patterns surrounding corridors, we ran Poisson regression models on data from 93 plots on ROWs and compared regression coefficients. We also determined nest success rates on a 1-km stretch of ROW. Seven species of shrubland birds were common in powerline corridors. However, the nest success rates for prairie warbler (Dendroica discolor) and field sparrow (Spizella pusilla) were <21%, which is too low to compensate for estimated annual mortality. Some shrubland bird species were more abundant on narrower ROWs or at sites with lower vegetation or particular types of vegetation, indicating that vegetation management could be refined to favor species of high conservation priority. Also, several species were more abundant in ROWs traversing unfragmented forest than those near residential areas or farmland, indicating that corridors in heavily forested regions may provide better habitat for these species. In the area where we monitored nests, brood parasitism by brown-headed cowbirds (Molothrus ater) occurred more frequently close to a residential area. Although ROWs support dense populations of shrubland birds, those in more heavily developed landscapes may constitute sink habitat. ROWs in extensive forests may contribute more to sustaining populations of early successional birds, and thus may be the best targets for habitat management.
Highlights
Open corridors along powerlines have become a prominent feature of landscapes throughout the world, leading to concern about their environmental effects
Our study focuses on declining shrubland bird species in North America, the results may be relevant to conservation in temperate woodlands in Western Europe and East Asia, where similar declines in early successional birds have been documented [28,29,30]
Shrubland species were abundant in Connecticut ROWs, the estimated probabilities of nests surviving to fledging for prairie warbler, field sparrow and eastern towhee were less than 21%, which is low compared to rates observed for shrubland birds in other ROWs and in silvicultural openings
Summary
Open corridors along powerlines have become a prominent feature of landscapes throughout the world, leading to concern about their environmental effects. Most ecological studies of powerlines have focused on potentially negative effects. Collisions with powerlines and electrocution can cause high mortality in some species of birds [1,2], and the open corridors along powerlines can fragment forests and other natural habitats, leading to a loss of biological diversity [3,4]. Few studies have investigated the positive effects of powerlines, and most of these have emphasized the potential role of powerlines as corridors connecting natural areas and reducing the effects of isolation for populations in habitat fragments [4,5,6]. Powerlines can play a more direct positive role, by providing extensive, continuous habitat for species that require low vegetation. The open rights-of-way along utility lines provide habitat for declining species of birds in North America [7], mammals in Australia [8], reptiles and amphibians in North America [9] and insects in North America and Europe [10,11]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
