Forest Amount, Not Fragmentation or Connectivity, Increases Bird Species Richness

Though habitat amount, fragmentation and connectivity are considered important for biodiversity, it is unclear whether fragmentation or connectivity have strong effects on biodiversity independent of habitat amount. We aimed to determine the independent effects of these variables on species richness and presence of forest birds in Eastern Ontario, Canada. We selected 70 sites where landscape habitat amount, fragmentation and structural connectivity were uncorrelated with each other. We determined bird species richness and presence by deploying autonomous recording units at each site. Only habitat amount had a significant relationship with species richness; species richness increased until forest covered ~45% of the landscape. Both habitat amount and connectivity had significant effects on the presence of some individual species, but the direction of effect (positive or negative) varied by species. We suggest that increasing habitat amount and managing connectivity for certain species may be an effective conservation strategy for birds