PARENT SESSION
Poster Session #37: Invertebrate Ecology.
Thursday, August 9, 2001. Presentation from 10:30 AM to 12:00 PM. Exhibition Hall

Are 'sinkholes' aptly named? Larval odonate ecology and adult species diversity in southeastern New Mexico.

GAINES, KAREN¹, ¹

ABSTRACT- The Bitter Lake National Wildlife Refuge is an unusual complex of alkaline salt flats interspersed with wetlands and water-filled sinkholes. Recent collections of over ninety species of adult dragonflies and damselflies on the refuge suggest that the highest diversity of odonates in New Mexico may occur in this relatively small area. The composition of the resident breeding population and the factors that contribute to the observed adult species diversity were unknown. In order to resolve these issues, odonate exuviae (cast larval skins), larvae, and adults were collected periodically at more than thirty-five sinkholes exhibiting a wide range of physical and biological characteristics. Habitat data (water chemistry, aquatic vegetation, and fish species assemblages) were also collected at each sinkhole and used to determine ecological correlates of larval species diversity and distribution. Exuviae of one odonate species were the only exuviae found at many of the sinkholes surveyed, indicating larval tolerance of a wide range of ecological conditions. In contrast, exuviae of several species observed as adults throughout the refuge were found at only a few sinkholes, suggesting larval stenotopy (primarily with respect to water salinity) and thus limited suitable breeding habitat availability for those species. The composition of species breeding successfully at sinkholes did not correspond to the adult species composition found to date, indicating that these sinkholes may indeed represent sinks for dispersing individuals rather than sources of species diversity.

KEY WORDS: odonates, exuviae, larvae, biodiversity