Comparative Study of Spider Communities in Alfalfa and Soybean Ecosystems: Ground-Surface Spiders

Ground-surface spider communities were examined using pitfall traps during three consecutive growing seasons to determine whether a perennial crop (alfalfa) supported a more persistent community than an annual crop (soybean). Similarities were found between crops in species composition, seasonal patterns of evenness, and the relative abundances of guilds. However, differences were found in the seasonal trends of the number of individuals present, as well as species richness. Overall, the ground-surface spider community in alfalfa appeared to be better established than that in soybean. This was probably due to the more constant environment resulting from the relatively dense vegetation cover and the formation of a thatch layer in the perennial habitat.