| Popis: |
Human activities have greatly impacted terrestrial ecosystems through various forms of habitat modification including the creation of powerline corridors. The routine maintenance of powerline corridors to prevent vegetation interference with electricity transmission lines leads to the emergence of early successional vegetation surrounded by a forest matrix. An analogous situation emerges in the creation of openings for wildlife management purposes. To determine the ecological consequences of human-modified landscapes, I investigated the effect of environmental gradients generated by these landscape modifications on floristic composition. I also examined edge effects along three powerline corridors with different management histories and investigated pollination dynamics of goldenrod Solidago canadensis within a powerline corridor and around wildlife openings. Powerline corridor habitat had more species and greater Shannon diversity than adjacent forest habitat. Powerline corridor and adjoining forest habitat had 69% mean Jaccard similarity coefficient, and species richness declined sharply within 10 m from the corridor edge. Invasive plants were more abundant within powerline corridor, along powerline corridor edges, and along wildlife opening edges compared to forest habitat. More frequent disturbance at wildlife openings facilitated recolonization by other insect-pollinated plants, which meant that some goldenrod patches there experienced more pollinator visits compared to those within powerline corridors. However, pollen viability and amount of fruit set did not differ between the two landscape elements. This work further strengthens the case of managing for biodiversity within powerline corridors as evidenced by greater species richness and pollination dynamics within this human-modified landscape. |
