Microturbellarian species richness and community similarity among temporary pools:: relationships with habitat properties

Temporary water bodies exhibit a high level of biodiversity, much of which is unique to these habitats. Studies of microturbellarian community ecology in temporary pools are scarce, even though turbellarians are potentially important in organizing community structure. Moreover, there has been virtually no documentation of microturbellarians from Israel. We examined the relationships between several pool properties ( surface area, water depth, permanence and sediment depth) and microturbellarian species richness among 52 temporary pools at a single site. A total of 17 taxa of microturbellarians were identified, of which 14 were determined to genus or species level. Richness was positively related with surface area and with maximal sediment depth, together explaining 54% of the variance. In more intensive sampling of a subset of 18 pools, surface area was the only significant predictor, explaining 76% of the variance. Community dissimilarity was positively related with differences in both surface area and permanence. We identified three categories of pool size, each characterized by different turbellarian species: large pools were dominated by Castrada viridis and Gieysztoria cuspidata, intermediate pools by Dochmiotrema limicola, and many of the small pools by Gieysztoria ornata and Olisthanella obtusa. Large pools contributed the most to regional diversity, with 11 of the 17 observed taxa. However, some species were unique to small pools. Thus, in order to maintain maximal regional diversity of temporary water turbellarians, it is important to conserve habitats containing pools of various sizes.