Community assemblage patterns of odonates inhabiting a wetland complex influenced by anthropogenic disturbance

Abstract

Abstract. Many wetland complexes around the world are highly influenced by human activity (chiefly land conversion for agriculture). Measuring the impact of such activity hinges not only upon using appropriate wetland indicator taxa but also upon metrics that are sensitive enough to capture subtle effects. Over a 5‐year period, we quantified the distribution and community structure of odonates (dragonflies and damselflies) occupying a wetland complex in Texas. When using traditional community metrics, there were no significant differences in diversity or evenness in the odonate assemblages in wetlands surrounded by the two dominant regional forms of land use (tilled cropland and grassland). Similarity analyses likewise failed to detect any significant differences in odonate community composition with land use. Discriminant function analysis, however, revealed that species co‐occurrences could be distinguished on the basis of surrounding land use, which indicates that odonate assemblages in these wetlands are structured in a manner that typical community metrics fail to adequately describe. Differences between the approaches are discussed, particularly with regard to the use of presence–absence data.