Effects of tree species, number of trees, basal area and understory vegetation on the abundance and diversity of avian species

Abstract

We investigated the relationships between bird species diversity and vegetation abundance, size, and groundcover of a forest ecosystem. We measured three variables: tree species diversity, tree diameter at breast height (DBH), and the amount of understory vegetation. We collected data at the AmeriFlux1 and FASET2 tower plots at the University of Michigan Biological Station property, Pellston, Michigan. The number of birds and number of bird species significantly increased with an increase in groundcover. The number of birds and bird species decreased with an increase in number of trees. Also, the number of birds and bird species decreased with an increase in basal area (tree size). These observations indicate the number of birds and bird species decreased with an increase in number of trees and tree basal area and increased with an increase in groundcover; all indicators of bird species diversity varying because of differences in vegetation abundance, structure, size, and amount of understory vegetation.