黑河流域中游地区荒漠—绿洲景观区啮齿动物群落结构

Rodent community structure of desert-oasis landscape in the middle reaches of the Heihe River

2005年4–5月和9月对黑河流域中游地区荒漠-绿洲景观区不同生境中啮齿动物群落结构进行了研究。在甘肃省张掖市高台县黑泉乡选择流动沙丘、含砾沙漠、固定沙地、荒漠灌丛、防护林带、灌耕草地、灌耕农田和河岸草地等8种代表性生境,采用活捕法(4,800铗日)共捕获啮齿动物254只,隶属于3科8属9种。利用捕获记录计算了群落结构特征指数,进一步利用Pearson相关系数考察了不同生境啮齿动物群落的相似性,并在此基础上对不同生境的啮齿动物群落作了聚类分析。群落结构特征指数表明,啮齿动物物种多样性(用Shannon-Wiener指数测度)在灌耕草地中最低(0.6859),在固定沙地中最高(1.7036);物种均匀度(用Pielou均匀度指数测度)在流动沙丘中最低(0.6531),在河岸草地中最高(1.0000)。聚类分析结果显示,研究区啮齿动物群落可以分成荒漠型群落和绿洲型群落两大类。三趾跳鼠(Dipussagitta)在荒漠型生境中密度较高,总体上具有优势地位,尤其是在流动沙丘生境中占据绝对优势;黑线仓鼠(Cricetulusbarabensis)在植被较好的绿洲型生境中占据优势地位,但在流动沙丘外的其他荒漠型生境中也有发现。除五趾跳鼠(Allactagasibirica)外,其他种类的跳鼠只在荒漠型生境中发现。本次调查没有在防护林内部生境中捕获啮齿动物,但在林缘区域仍有捕获记录。啮齿动物群落物种多样性指数与捕获率间无显著关联(r=0.240,P=0.566)。本研究提示人为干扰可能对维持研究区域的啮齿动物多样性有积极意义。

By using living trapping, we studied the characteristics of rodent communities in desert-oasis landscape in the middle reaches of the Heihe River, Gansu. Field study was carried out from April to May, and September in 2005. A total of 4,800 living trappings were set in eight typical habitats, including sand dune, gravel-sandy desert, stabilized sandy desert, desert scrubland, shelter belt, irrigated grassland, irrigated crop field and riverine grassland. In total, 254 individuals representing 9 species, 8 genera, and 3 families were captured. We then calculated characteristic indices of community structure for the eight habitats. The species diversity index （Shannon-Wiener index） ranged from 0.6859 （irrigated grassland） to 1.7036 （stabilized sandy desert）, while Pielou evenness index ranged from 0.6531 （sand dune） to 1.0000 （riverine grassland）. Using Pearson correlation coefficients and hierarchical clustering, we could roughly classify the 8 rodent communities as 2 major types, i.e. desert type and oasis type. Desert-type habitats generally harbored higher species diversity and population density. Dipus sagitta showed a high density and was dominant in desert-type habitats, especially in sand dune. Cricetulus barabensis was common in habitats with relatively high vegetation coverage but also recorded in desert-type habitats （sand dune excluded）. Among the four jerboa species, only AUactaga sibirica was found in oasis-type habitats. We did not capture any rodent in core region of shelter belt. However, we did record some individuals in the edge region. No significant relationship was found between Shannon-Wiener diversity index and capture rate（r=0.240, P=0.566）. Our results suggest that human disturbance in study area may have been beneficial to maintain rodent diversity.