Some like it cool: microclimates affect arthropod biodiversity and abundance on roof-top gardens

Roof-top gardens mitigate storm water runoff, filter pollutants, and alter the local microclimates of urban areas by reducing heat island effect. Little is known about roof microclimates and their effect on arthropod biodiversity and abundance. Preliminary data from biweekly sampling during the 2014 season yielded a total of 1,242 arthropods from 4 classes and 13 orders. It was noted during this survey that cooler areas, defined by daily shade and ambient temperature, had higher arthropod abundances.  After defining microclimate zones using a combination of temperature, relative humidity, and light intensity, this study will examine differences in arthropod diversity and abundance between the zones present on a young Sedum roof in downtown Denver. To test the hypothesis that arthropod abundance differs according to microclimate, resident arthropods will be collected bi-weekly during the 2015 summer season by pitfall, suction and hand sampling methods.