Study On The Community Structure And Diversity Of Piders In Alfalfa Fields And Natural Grassland

In this paper，a survey was made to collect spiders in alfalfa fields and arid grasslands from April toOctober in2012, in Zhong Niu Chang Ecological Station, HuTuBi, Xinjiang, and Yashan, Urumqi, LocustObserve and Predict Station, Manas county, Xinjiang. From the survey, a total of3082spiders werecollected, belonging to85species in49genera of16families. The main results are as follows:(1) There was a systematically investigated spider community of alfalfa fields in Xinjiang. This surveycollected1796spider individuals (1269in mowing field and527in seed fields). Those spiders wereidentified as60species in35genera of13families. In the desert natural pastures, we collected spider1286individuals (1140in the Yashan and146in the Nanshan), which were identified as42species in25generaof12families.(2) The dominant species in alfalfa field: Pardosa falcata, P. astrigera, and Neoscona pseudoscylla.Natural grassland’s dominant species: Alopecosa xinjiangensis, A. cursor, Pisaura mirabilis, Trochosaruricola, Gnaphosa licenti. The dominant species is different in different months and the type and quantityof the dominant species varies with vegetation growth.(3) The richness(53), diversity index (2.4477)and evenness index (0.6165)of spider species were at ahigher level in alfalfa mowing field than in alfalfa seed field. The influence of mowing was obvious at thebeginning in alfalfa field, declining in all diversity parameters examined. In the desert grassland, therichness(31), diversity index(2.3253)and evenness(0.6650) of spider species were higher in forests than indesert.(4) The maximum value of spatial-temporary niche breadth in alfalfa fields is Erigonedentipalpis(0.4770), The niche overlap value of Pardosa falcata and Pardosa astrigera is the highest(0.1779). The maximum valuer of space-time dimensional niche breadth in natural grassland is Pisauramirabilis (0.6483), the largest of niche overlap is Gnaphosa licenti and Alopecosa cursor (0.4355).