Playas are ephemeral wetlands that are the only source of aboveground freshwater in the southern Great Plains, making them of vital importance to aquatic and amphibious animals. Playas are also highly threatened from anthropogenic land use (chiefly agriculture, which decreases hydroperiod through increased sedimentation). We examined community structure of adult odonates (dragonflies and damselflies) in playas differing in the 2 main regional forms of surrounding land use (cropland vs. grassland). Analysis of odonate diversity revealed high overlap between cropland and grassland playas. Traditional species-area theory did not fit observed patterns, as there appears to be a threshold playa size that supports maximal odonate diversity; this nonlinear response may reflect a tradeoff between hydroperiod and availability of emergent vegetation that is required for perching and oviposition. Since agriculture effectively reduces playa depth but not size of the overall playa watershed, this may mean that cropland playas serve as "ecological traps." This property has important implications for regional odonate diversity.
Hernandez, K. M.; Reece, B. A.; and McIntyre, N. E.
"Effects of anthropogenic land use on Odonata in playas of the Southern High Plains,"
Western North American Naturalist: Vol. 66
, Article 1.
Available at: http://scholarsarchive.byu.edu/wnan/vol66/iss3/1