PARENT SESSION
Oral Session #12: Landscape Ecology: Theory and application. Presiding: C. Johnston.
Monday, August 6, 2001. 1:00 PM to 5:00 PM. Madison Ballroom D.

Partitioning species diversity across scales: Statistical tests on components of insect diversity in deciduous forests.

Crist, Thomas¹, Veech, Joseph¹, Summerville, Keith¹, Gering, Jonathan¹, ¹

ABSTRACT- Additive partitioning of species diversity provides a quantitative description of how species composition and dominance vary with spatial scale. We extended the methods of diversity partitioning with statistical tests on additive components of diversity across multiple scales, and applied them to beetle and moth communities sampled from different forest stands and regions. Individuals were randomly allocated among samples in computer simulations to produce null distributions that conserved overall species richness and abundance. The additive partitions of species richness, dominance, and evenness of these null communities were then compared to those in observed communities. Tree-crown beetles comprising 272 species obtained from a beech-maple forest showed significantly high levels of beta diversity among trees (28%) and stands (53%). At broader scales, 537 moth species were sampled in large and small forest fragments and in two different regions. We detected significantly high levels of beta diversity between large and small forest fragments (21%) and between regions (29%). Our findings suggest that significant levels of beta diversity might be common at various spatial scales, and that statistical tests on diversity partitioning can sharpen our understanding of how local and regional processes influence species diversity.

KEY WORDS: forest insect diversity, additive partitioning of diversity, null community models, spatial scales