沙地柠条(Caragana)灌丛微生境节肢动物群落特征

以宁夏荒漠草原柠条（Caragana）灌丛林地为研究对象，于2011年春、夏、秋季，利用陷阱诱捕法，调查了灌丛微生境节肢动物群落分布特征。结果表明：（1）调查共获得节肢动物9目31科32个类群，分属于4种功能群（植食性、捕食性、腐食性和杂食性）。其中，优势类群为蚁科（Formicidae）和拟步甲科（Tenebrionidae），个体数占总个体数的71.97%；常见类群有7科8个类群，个体数占总个体数的19.72%；其余22个类群为稀有类群，个体数仅占总个体数的8.30%。（2）随着季节变化，灌丛内外节肢动物类群组成和个体数分布均发生改变。春季灌丛内外均包括优势类群、常见类群和稀有类群；夏季灌丛内外均包括优势类群，而灌丛下仅有常见类群，无稀有类群，灌丛外既没有常见类群也没有稀有类群；秋季灌丛内外均有优势类群和常见类群，但灌丛内外均无稀有类群。（3）夏季灌丛内外共有类群数最少，相似性指数最低，秋季次之，而春季灌丛内外共有类群数最多，相似性指数也最高。（4）春季和秋季，灌丛内外微生境中节肢动物个体数、丰富度和Shannon指数均无显著差异（P>0.05）。夏季，节肢动物个体数灌丛内外无显著差异性（P>0.05），但丰富度和Shannon指数均表现为灌丛内显著高于灌丛外（P<0.05）。（5）春季灌丛内外捕食性、植食性和杂食性节肢动物的个体数和丰富度均无显著差异性（P>0.05）；但是，腐食性动物个体数和丰富度均表现为灌丛内显著高于灌丛外（P<0.05）。夏季，仅有捕食性动物丰富度呈现出灌丛内显著高于灌丛外（P<0.05），而其他指标灌丛内外均无显著差异性（P>0.05）。秋季，每种功能群动物的个体数和丰富度灌丛内外均无显著差异性（P>0.05）。沙地灌丛内外生境中节肢动物的空间分布，既与灌丛本身生理生态学特性相关，也与季节性降雨和温度等气象条件的改变密切相关。

Spatial Distribution of Arthropod Community between Caragana Shrub Microhabitats

A field survey was undertaken to investigate the community composition and spatial distribution of arthropods in the desertified steppe of Ningxia. The pitfall traps were used to collect specimens in spring, summer and autumn of 2011. (1) The traps captured 32 taxonomical groups belonging to 31 families, 9 orders and 2 classes. These taxonomical groups were classified into predator, herbivore, sapropages, and omnivore. The two dominant groups were the Tenebrionidae and Formicidae families, together making up 71.97% of total ground-dwelling arthropods. There were 8 common groups, accounting for 19.72% of total individuals, and 22 rare groups making up 8.30% of total individuals. (2) The results indicated remarkable changes in the community composition and their abundances of arthropods between shrub microhabitat along with seasonal changes. In spring, the shrub microhabitats harbored the dominant group, common group and rare group, while in the summerthe shrub microhabitats only harbored the dominant group, without common group in the open space and without rare group in either shrub microhabitats. (3) The number of shared groups between shrub microhabitats was low in summer, which was followed by the autumn, whereas in the spring there were a considerably greater number of shared groups between shrub microhabitats. The order of Sorenson index was found to be followed as:spring > autumn > summer. (4) In both spring and autumn, there were no significant (P>0.05) differences in total abundance, richness and Shannon index between shrub microhabitats, whereas in the summer, a markedly (P<0.05) greater richness and Shannon index was found beneath the shrub cover relative to the open spaces. (5) In spring, only the abundance and richness of sapropages was found to indicate markedly (P<0.05) greater values beneath the shrub cover relative to the open spaces. In summer, only the taxa richness of predator was found to indicate markedly (P<0.05) greater values beneath the shrub cover relative to the open spaces. In autumn, however, there were no significant (P>0.05) differences in the abundance and richness of functional groups between shrub microhabitats. (6) It was concluded that the spatial distribution of arthropod community between shrub microhabitats was correlated with both the ecological attributes of shrub plants and the seasonal changes of rainfall and temperature.