Powerline Easements as Refugia for State Rare Seepage and Pineland Plant Taxa

Philip M. Sheridan, Steve L. Orzell, and Edwin L. Bridges

Field surveys of selected powerline easements on the inner coastal plain of Georgia, Maryland, and Virginia uncovered significant rare seepage and pineland plant taxa in comparison to the surrounding fire-suppressed and human altered landscapes. Surveys of selected powerline easements resulted in the discovery of 65 state rare plant species from 24 counties in three states. Twenty-two state rare plant species are documented on powerline easements for Georgia, 12 for Maryland, and 31 for Virginia. Two state endangered and three state threatened plants were found in Georgia powerline easements while 3 state endangered and two state threatened were found in Maryland. Rare plant taxa occur on powerline easements for several reasons: right-of-way management strategies have replaced natural disturbances; naturally open herbaceous seeps harboring rare plant taxa were crossed by powerlines; seeds were dispersed to the easement by wind or other vectors; plants were present in low numbers, dormant or in seed banks prior to powerline easement clearing; or a combination of some or all of these factors. Periodic mechanical clearing of brushy vegetation to maintain powerline easements can replace natural disturbances such as fire and beaver activity and thereby may allow some disturbance adapted rare plants to persist that might otherwise be locally extirpated through fire suppression and subsequent woody invasion of open space habitat niches. Powerline rare plant refugia might serve as a local measure of biodiversity in regions where the surrounding natural vegetation has been highly altered or subjected to fire suppression and seepage bog or pineland plants are now found in powerline easements.

Keywords: Powerlines, rights-of-way, biodiversity, state rare plants, pitcher plant bogs