Data set ID:
**The objective of the present research was to determine whether there have been changes in the structure and function of the surface (0-20cm) soil system, the zone most affected by litter decompos
ition, which is associated with the rapid movement of mesquite from historical habitats (arroyo and playa fringe) into recent habitats (grassland and dunes). We hypothesized that the soil biotic communities would be poorly developed in the recent mesquite habitats because of lower soil C and nutrient concentrations. Data set contains Baerman Funnel extracted nematodes (fungal feeders, bacterial feeders, omnivore-predator, total plant parasites, total nematodes) and Elutriator extracted nematodes (fungal feeders, bacterial feeders, omnivore-predator, total plant parasites, total nematodes).
Field and electronic data sheets
**The soils were sampled in October 1986 at the end of the hot, dry summer season when surface soil biota in the Chihuahuan Desert reach their maximum densities. At each habitat type location (playa, arroyo, grassland and dune) soil samples were collected from the midcanopy beneath six mesquite plants at two depths (0-10 cm and 10-20 cm), using a bucket auger soil corer (7.5 cm diameter, 10 cm depth). The samples were placed in plastic bags, stored in a portable cooler, and then transported to the laboratories. These samples were later divided into subsamples for nematode extractions. Nematodes were recovered from soil samples using a semi-automatic elutriator with sugar flotation-sieving (Byrd et al. 1976). This method was selected from a comparison with the Baerman Funnel Technique (Freckman and Virginia 1989). Nematodes were counted and separated into functional groups of (1) fungal feeders, (2) bacterial feeders, (3) omnivore-predators, and (4) plant feeders (Freckman et al. 1987, Freckman and Baldwin 1990). Nematode densities were corrected for soil moisture content, but were not adjusted for extraction efficiency due to the variability in soil textures between sites.
*Four mesquite ecosystems were stuided: playa, coppice dune, arroyo, and grassland. The arroyo, grassland, and a playa site were loacated on the NSF Jornada Long Term Ecological Research (LTER) site situated 40 km north of Las Cruces, NM, in the northern Chihuahuan desert. A coppice mesquite dune site was located on the adjacent USDA Jornada Experimental Range about 15 km from the above sites.