Abstract
In the present paper the diversity of the Costa Rican water mite fauna is analysed and compared with those of other regions. About 20000 water mites in 74 genera and 21 families were collected at more than 500 sample sites in various regions and different ecotones throughout Costa Rica (Central America). Numerous types of running- and standing-water habitats as well as springs were sampled. The frequency- and dominance-structure of the Costa Rican water mite fauna is discussed. The α- and the γ-diversities of the water mites of different regions, habitats, and elevations are compared. Different scales of diversity are distinguished. Water mite diversity decreased with elevation. The habitats with the highest α-diversity were streams (19 genera) and brooks (18 genera). Similar levels of diversity were found in the northwestern (dry forest), southwestern (rain forest), and northeastern (rain forest) regions of Costa Rica. Greater diversity of water mites was found in pristine forest regions than in open pasture areas, with as many as 19 genera found at a particular sample site. The α- and γ-diversities of the Costa Rican water mite fauna are consequently within the same range as those of other regions of Central America, North America, and Europe. The diversity in terms of total species number is about twice as high in tropical regions as in temperate regions.
