Effect of landscape position on plant diversity and richness on electric transmission rights-of-way in New York State

Rights-of-way are kept free of tall trees to insure reliability of electric service. Selective management techniques such as application of cut-stump herbicide and stem foliar herbicide are used on some rights-of-way to remove undesirable tree species while minimizing disturbance to shrub and herbaceous vegetation. Because rights-of-way typically traverse broad productivity and disturbance gradients over large geographic areas and harbor both native and non-native species, they offer unique opportunities to study plant species diversity patterns and their underlying causes at different scales. Plant cover on six managed rights-of-way in forested landscapes of New York State was sampled to determine the effect of landscape position (i.e., xeric, mesic, and hydric sites) on species composition, diversity, and richness and contribution of non-native species. Species composition among sites was compared using redundancy analysis in which the individual covers of the most common species were ordinated with treatment levels. Diversity, species richness, and contribution of non-native species were compared using analysis of variance. Redundancy analysis shows trends in the occurrence of common species based on landscape position. Analysis of variance indicates diversity, richness, and contribution of non-natives are greater on the rights-of-way versus the adjacent woods for xeric and mesic positions, whereas no differences were indicated between rights-of-way and adjacent woods for hydric positions. Key words: rights-of-way, selective management, diversity, competition, stress, invasive species.