Extreme disturbances eliminate aquatic biota and alter community structure and function. During a supraseasonal drought in north-central Texas in the summer and fall 2006, macroinvertebrate communities from persistent groundwater-dependent macrohabitats of varying hydrology and riparian shading were investigated to study their role as invertebrate refugia, and to characterize the taxonomic and functional community structure of benthic assemblages. Ash Creek was the only stream with surface flow within a 35-km radius during the drought. Two perennial and three intermittent stream sites were studied that included perennial riffles, a perennial pool, shaded disconnected pools, and disconnected pools in full sun. Riffles had significantly higher taxa richness, EPT (Ephemeroptera, Plecoptera, and Trichoptera) richness, proportion of lotic taxa, and diversity than other macrohabitats. Macrohabitats were refugia for 106 benthic macroinvertebrate taxa, and perennially flowing habitats contained 19 taxa (17.9% of total taxa) not collected in disconnected pools. Larvae and pupae of caddisflies Marilia spp., Oecetis spp., Helicopsyche spp., and riffle beetle Microcylloepus spp. larvae and adults demonstrated resistance to drought by their presence in shaded disconnected pools without surface flow for over a month. Gathering-collectors were the most dominant and taxonomically diverse functional feeding group (FFG) in all macrohabitats. Scrapers ranked second in dominance in riffles, followed by predators; however, predators were the second most dominant FFG in all pool habitats. Continued overabstraction of groundwater in the region could lead to loss of perennial riffles and pools and extirpation of lotic taxa, such as Lutrochus spp., Mayatrichia spp., and Marilia spp., and dramatically alter community structure and function.Keywords: drought refugia; aquatic insect community; headwater stream; groundwater-dependent ecosystem; perennial stream IntroductionThe north-central region of Texas, with rainfall totaling less than 882 mm annually, is a semiarid ecosystem (NOAA 2012a). The region has many small streams and springs that are important to the maintenance of aquatic diversity and community structure (Brune 2002). The aquatic invertebrates found in these streams are important links between primary producers and secondary consumers in these systems. Because these streams are dependent on groundwater and springs to maintain flow, reductions to these water sources caused by droughts have been recognized as important forces shaping invertebrate assemblages in streams (Grimm and Fisher 1989;Dudley et al. 1990;Boulton and Lake 1992a;Stanley and Fisher 1992). Lake (2003) distinguished between two types of droughts: seasonal and supraseasonal. Organisms in streams subjected to predictable seasonal droughts *Corresponding author. Email: rburk1@atu.edu 252 R. A. Burk and J.H. Kennedy are more likely to have evolved adaptations to survive reduced or lack of flow. However, supraseasonal droughts cannot be foreseen and build gradu...

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Sales and marketing professionals understand that "the greener the better" applies to sales. However, there is a risk of the marketing department overstating what the company is doing for the environment.If a company is unsure, it is better to publish less information which is accurate than more information with potential inaccuracies.