Species Composition and Trophic Structure of
Insect Communities in Texas Prairies
Introduction
Knowledge of local and regional patterns of variation in species composition and community structure is important for conservation planning, particularly as habitats become highly fragmented. Native prairie, having been reduced to less than 1% of its former extent by conversion to agricultural and other human uses, suppression of fire, and alteration in grazing regimes (Joern and Keeler 1995), is one of the most highly fragmented habitats in North America. Many studies in this formerly vast ecosystem have been conducted on highly-visible species, such as bison (Bos bison), prairie dogs (Cynomys ludovicianus), and pronghorn (Antilocapra americana). However, for conservation efforts to be more ecosystem-focused, information on the less charasmatic species also is necessary.
Insects are a critical, although often under-studied, component of all ecosystems. Detailed studies have been conducted on population dynamics and community structure of insects in disturbed or successional grasslands (e.g., agroecosystems, Root and Kareiva 1984, Kemp and Barrett 1989; monoculture stands of weedy herbs, Root and Cappuccino, 1992; and oldfields, Evans and Murdoch 1968, Kroh and Beaver 1978, McBrien et al. 1983, Pinder and Kroh 1987, Hendrix et al. 1988, Caine et al. 1991, Root and Cappuccino 1992). A few studies have elucidated these attributes in native prairie with a focus on sites in the Great Plains (Cancelando and Yonke 1970, Risser et al. 1981, Evans 1989, Joern and Keeler 1995). As a result, little is known about species composition and structure of insect communities in the prairies that extend southward into Texas (Risser et al. 1981). To expand our understanding of the faunal structure of North American prairies, we compared and contrasted species composition and community structure of insects among habitats in coastal and central prairie in Texas. In addition, because entomofauna have been used to assess the ecological impact of habitat fragmentation (Klein 1989, Golden and Crist 1999) and biodiversity (Oliver and Beattie 1996a), studies such as ours lay important groundwork for conservation planning in remnant prairies (Kremen et al. 1993).
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