Differences in plant diversity relative to disturbance in a power-line corridor

Abstract Plant samples were collected within a power-line corridor located near York University to determine whether plant diversity is affected by different levels of disturbance. The study site was divided into three levels of disturbance: least (forest edge), intermediate (transmission towers), and most disturbed (field edges). Percent coverage and species identification was recorded to find species richness, Shannon-Wiener Index (H') and species evenness. The results of this study showed that the most disturbed sites displayed the highest amount of species richness; while the intermediately disturbed sites displayed the highest value of species evenness and abundance (H'). Further statistical analysis showed that there was a significant difference in the species richness and species evenness between the three levels of disturbance. The results found supports the intermediate hypothesis theory, which states the presence of intermediate disturbance results in the highest amount of diversity. This then demonstrates how too much disturbance results in a decrease in diversity, and too little disturbance also results in a decrease in diversity. It should be noted however that the site is far from a pristine environment. Overall the site is heavily disturbed because it is surrounded by industrial buildings, and the forest patch is right behind a railway. This means that the levels of disturbance are all relative to the different areas studied, and that different results may be found if this was tested in a power-line corridor neighbouring a more pristine forest.