Animal consumers have important roles in ecosystems, determining plant species composition and structure, regulating rates of plant production and nutrients, and altering soil structure and chemistry. This is data for numbers and species of seed harvester ant nests mapped from each of the SMES study plots. Seed harvester ant nests were mapped on each of the study plots once each year in the autumn. Ant nest maps were drawn on to pre-designed plot diagrams. Each nest was located on the diagram in reference to one of the 36 vegetation quadrat marker posts. The distance from the post, direction from the post, and species name were plotted on the map diagram. Data such as total numbers of nests of each ant species, and spatial arrangement of nests, were then taken from the diagram maps. The following question was asked: Do small mammals interact with other herbivore and granivore consumers enough to affect the species composition and abundances of other consumers such as ants?
The Small Mammal Exclosure Study plots are located in a grassland and shrubland. These plots were established in 1995 to monitor the effects of indigenous small mammals on plant communities across the Chihuahuan Desert grassland and shrubland. There are four blocks distributed randomly at each site; each block contains three treatments plots: unfenced control (C), fenced with poultry wire to exclude lagomorphs (L), and fenced with hardware cloth and poultry wire to exclude rodents and lagomorphs (R). The three treatment plots in each block are separated by 20 meters and were randomly assigned to one of the four plots for each block. Each plot (36m x 36 m) contains 36 permanent 1 m2 subplots. Vegetation measurements have been consistently taken on these subplots since 1995 and in 1996 fenced exclosures were installed.
Data Collection Methods:
Ant nests were mapped from each of the study plots once each year, in the autumn. An observer walks east to west and west to east along each of the 6 lines of rebar markers looking for ant nests. The observer locates each ant nest on a diagram of the study plot using rebar markers as reference points. The position of the nest relative to the nearest rebar was marked on the diagram as a small circle. The species of ant was noted as a 2-letter acronym, first letter of the genus, and first letter of the species, within the circle on the paper. The distance from the rebar was noted in meters, and the direction from the rebar was indicated on the diagram by a line drawn between the rebar and the nest. Ant species mapped include: all Pogonomyrmex species, Aphenogaster cockerelli, and Myrmecocystus species (non-seed harvesters). Pheidole species were not mapped.
Metadata entered into access. 7 April 2009 tlk
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