Functional groups affected differently by disturbance and landscape
Wood-boring beetles and their predators are impacted differently by habitat fragmentation, the availability of native vegetation, and plant diversity. However, a functional diversity approach has not previously been used to explore landscape and local-scale responses among these communities. This information could be used to determine appropriate forest management that optimizes natural control of pest wood-borers in different landscape contexts. We used biological and ecological traits of longhorn beetle species (Coleoptera: Cerambycidae) and their generalist beetle predators to categorize these into functional groups. Measured traits included estimates of visual conspicuousness of beetles to insectivore birds, another significant predator group of wood-borers. Abundance data on these species was collected throughout the state of Indiana among sites representing a gradient of forest fragmentation. Functional groups and functional diversity indices were calculated with trait and abundance data for these communities. Functional diversity indices of beetle communities along the landscape gradient were used to investigate predator and prey response to landscape scale and habitat fragmentation.
Results showed that functional richness displays a threshold response to landscape fragmentation. Cerambycid beetle functional diversity was found to respond to the landscape at landscape scales between 0.6–2.4 km.