PARENT SESSION
Oral Session # 75: Biodiversity II.
Presiding: K Kirkman
Thursday, August 7. 1:30 PM to 5:00 PM, SITCC Meeting Room 100.

Does size really matter? Factors affecting larval odonate diversity patterns in a desert sinkhole complex.

Gaines, Karen^*,1, ¹ University of New Mexico-Albuquerque, Albuquerque, NM, U.S.A.

ABSTRACT- The Bitter Lake National Wildlife Refuge in southeastern New Mexico contains an unusual ecological mosaic consisting of desert scrub and grassland surrounding dozens of saline water-filled sinkholes of varying sizes, geomorphologies, and water chemistries. Nearly one hundred species of adult dragonflies and damselflies (Order Odonata) have been collected on the refuge, representing the highest diversity of odonates in the state of New Mexico. In order to characterize the distribution and diversity patterns exhibited by the breeding odonate population, thousands of exuviae (final instar larval exoskeletons) were periodically collected at over thirty sinkholes in 2000, 2001, and 2002. Multivariate analyses of sinkhole dimensions and water quality data revealed that while larger sinkholes did tend to support more diverse larval odonate communities, average winter salinity levels explained nearly 70% of the variation observed in species diversity, as species with broad larval salinity tolerances successfully bred in most sinkholes visited by adults regardless of sinkhole size. In contrast to predictions of island biogeography theory, this study suggests that in certain cases, individual species characteristics (e.g. larval stenotopy) may have a far greater influence on community diversity patterns than does habitat patch size.

Key words: dragonflies, diversity, odonates, island biogeography theory