| Popis: |
We compared avian communities and vegetation characteristics in invaded and uninvaded pine barren ecosystems to test whether invasive woody plants were altering native bird communities. We hypothesized that structural changes in vegetation caused by the invasion of fire-intolerant deciduous trees were altering bird communities in the Albany Pine Bush, east central New York State. We recorded bird calls at 55 stations during breeding season to estimate abundances of breeding birds in areas dominated by fire-dependent pine-shrub savanna and areas dominated by invasive hardwoods (black locust, Robinia pseudoacacia, and aspens, Populus tremuloides and P. grandidentata). Vegetation surveys were conducted surrounding each station to quantify woody plant composition and structure. Sites characterized as invaded had more vegetation layers, twice as much closed canopy, and higher tree stem densities in all but the largest (> 25 cm dia) size classes. Forty-seven bird species were recorded; thirty-three at ... |
