Invertebrate communities in vegetated playa wetlands
Anderson, James T.
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Playa wetlands on the Southern High Plains (SHP) of Texas provide important and essential habitat to the native flora and fauna in the region. Wetland invertebrates are important to the biodiversity in the SHP, serve as food sources for waterfowl and other wildlife, and contribute to nutrient cycling in playas. Little is known about macroinvertebrate communities in playa wetlands of the SHP or in any seasonally flooded wetlands managed for moist-soil plants (Le., moist-soil management). Moist-soil management produces abundant seeds, that are consumed by dabbling ducks and other wildlife. An examination of macroinvertebrate communities in moistsoil managed playa wetlands is needed to determine the potential for management to increase invertebrate production, assess the importance of invertebrates in the diets of dabbling ducks, and determine their influence in attracting waterbirds to playas. In addition, by altering hydroperiods and management regimes, hypotheses concerning factors that are most influential in determining invertebrate abundance (density and biomass), community development, and competition can be tested. The objectives of this study were to (1) compare waterbird use during diurnal and nocturnal periods and potential waterbird use-days, based on seed and invertebrate abundance, among water legunes (September and November flooding) and management scenarios (moist-soil managed and unmanaged) in playa wetlands; (2) determine the importance of invertebrates in the diet of wintering and migrating green-winged teal (Anas crecca) as it relates to feather moh intensity; (3) compare macroinvertebrate biomass, density, community structure, and diversity among playas subjected to different water regimes (September and November flooding) and management scenarios (moist-soil managed and unmanaged); (4) determine if colonization from other areas or persistence in playas is more prevalent for invertebrates inhabiting playa wetlands; (5) compare production of protein and energy between invertebrates and seeds, water regimes (September and November flooding), and management scenarios (moist-soil managed and unmanaged) in playa wetlands; (6) determine the effects of physicochemical (e.g., plant species, water depth, water temperature, pH, dissolved oxygen, electrical conductivity) characteristics on playa wetland invertebrate abundance and presence; and (7) determine if patterns of niche partitioning occur among coexisting snails within microhabitats of playas. I chose snails as my test subjects for objective (7), because there were only 3 species that are abundant and wide-spread in my study playas.