Importance of transmission line corridors for conservation of native bees and other wildlife

Abstract

In forested regions, electric transmission line corridors often provide large linear expanses of managed early successional habitats for sun-loving plants, invertebrates, and vertebrates, many of which are legislatively protected or otherwise targets of conservation efforts. We sampled the bee fauna at 27 randomly selected sites along a 140-km (89-mile) segment of a transmission line that extends from Connecticut to New Hampshire. Each site contained two plots, one within the powerline corridor and another in a closely adjacent forest. Data were collected over a 12-week study period (late May to early August) with corridor plots yielding more than twice as many bee species and more than ten times the number of individuals than the forest plots. The aggregate richness for the 54 plots (=205 species) represents nearly half the bee fauna of New England with species estimation curves suggesting that many additional species were resident but went unsampled. Two globally rare species, Epeoloides pilosulus and Macropis ciliata, were documented from the powerline plots. The time-extended (five-year) vegetation management cycles currently used by many utility companies in New England result in a dynamic array of vegetation composition and structure that supports a multitude of bees as well as other insects, reptiles and amphibians, shrubland birds, small mammals, and other early successional taxa.