Microarthropods of a desert tabosa grass ( Hilaria mutica) Swale.

In the clay-silt soil of a tabosa grass swale in S New Mexico, maximum population densities of soil microarthropods occurred in September (48 400 m^-2), lowest densities in July (1250 m^-2). These densities were 50% lower than those reported for well-drained soils on the upper parts of the same watershed. Prostigmatid mites made up 67% and cryptostigmatic mites, 26%, of the total microarthropod population. The ratio between prostigmatic and cryptostigmatid mites, c 4:1, was consistent throughout the year. Overall densities of microarthropod groups were correlated with soil moisture but many individual taxa were not. The most numerous and frequently occurring taxa (nanorchestid, tydeid and bdellid mites (Prostigmata); Aphelacarus sp. and Cosmochthonius sp. (Cryptostigmata)) are common in all Chihuahuan desert habitats and indeed in other North American desert areas.-from Authors