银川平原不同种植模式下苜蓿田地表蜘蛛群落多样性及时间动态模拟

为探究不同种植模式对苜蓿田地表蜘蛛群落多样性及个体数量的影响,采用陷阱法对银川平原苜蓿-小麦邻作、苜蓿-玉米邻作和苜蓿-果园间作3种不同种植模式下的人工苜蓿田地表蜘蛛群落进行了调查,研究其多样性、丰富度、均匀度及优势度指数的差异和变化,并利用Gaussian函数对各指数进行时间序列动态拟合,分析了3种种植模式下人工苜蓿田地表蜘蛛群落总个体数量的时间动态变化。结果显示,该地区共收集到蜘蛛标本2 761头,隶属12科19属28种,其中优势种为星豹蛛Pardosa astrigera、甘肃平腹蛛Gnaphosa kansuensis和白斑隐蛛Nurscia albofasciata。2种邻作模式下,苜蓿田地表蜘蛛群落多样性、丰富度、均匀度及优势度指数同间作模式下的各指标均有显著差异,且多样性指数最大值出现时间分别为5月7日和5月18日,均早于间作模式下的7月3日。Gaussian函数拟合结果表明,苜蓿-小麦邻作模式下苜蓿田地表蜘蛛种群高峰期持续时间最长,为121.92 d,苜蓿-玉米邻作模式下2次种群高峰间隔时间最短,为49.2 d。苜蓿-小麦邻作模式下苜蓿田地表蜘蛛群落的个体数量最大值出现在5月上旬,其它2种模式下均出现在5月中旬。

Community diversity and temporal dynamics of spiders in alfalfa fields under three different cropping patterns in Yinchuan Plain

In order to explore the effects of cropping patterns on the species diversity and abundance of ground-dwelling spiders, pitfall traps were used to capture the spiders in alfalfa fields under three different cropping patterns, including alfalfa-wheat neighbor-planting, alfalfa-corn neighbor-planting, and alfalfa-orchard intercropping in Yinchuan Plain. The diversity, richness, evenness, and dominance indexes of spiders in three cropping patterns were also computed to examine the differences among them. The temporal dynamics of the populations were modeled by using a Gaussian function, which could be used to calculate population dynamics of spiders. A total of 2 761 spiders belonging to 12 families, 19 genera and 28 species were collected. The dominant species were Pardosa astrigera, Nurscia albofasciata and Gnaphosa kansuensis in the alfalfa fields. There were significant differences in the diversity, richness, evenness and dominance index of the spider community between neighbor-planting pattern and intercropping pattern. The maximum value of diversity and dominance indexes of spider community in alfalfa fields under two neighbor-planting patterns appeared earlier (May 7 and May 18) than under the intercropping pattern (July 3). The Gaussian function of spider community diversity dynamics indicated that ground-dwelling spider community in alfalfa-wheat neighbor-planting fields had the longest growth stage (121.92 d), while the spider community in alfalfa-corn neighbor-planting fields had the shortest interval between two growth stages (49.2 d). The number of individuals in the spider community in alfalfa-wheat neighbor-planting fields reached the peak at early May, but at mid-May for other fields.