不同干扰下阿拉善荒漠啮齿动物优势种对气候变化的响应

Responses of dominant rodentspecies to climate change in different disturbed habitats in the Alashan desert

气候变化已对物种分布范围和丰富度产生了极大的影响。荒漠生态系统对气候变化的反应可能更加敏感。作为荒漠生态系统的重要组成者,了解荒漠啮齿动物特别是优势鼠种将对气候变化如何响应,对于荒漠地区生物多样性的维持将具有重要意义。2002—2010年,采用标志重捕法对阿拉善荒漠4种不同生境下啮齿动物优势种群进行了研究,分别利用Spearman相关分析以及典范对应分析(Canonical Correspondence analysis,CCA)对啮齿动物优势种群动态与年平均温度和年降水量的相关性进行了分析。结果表明,不同啮齿动物优势种对温度和降雨的响应不同,尤其以子午沙鼠表现最为显著。跳鼠对温度的适宜性要高于仓鼠科的子午沙鼠和黑线仓鼠,而仓鼠科啮齿动物对降雨的适宜性高于跳鼠。较小尺度上的人为干扰更可能从改变食性和生境的途径上加剧或缓冲降雨对荒漠啮齿动物优势种的影响,而不是改变温度对啮齿动物的作用。

The Northern Hemisphere of the earth has been experiencing remarkable climate warming in last century.Climate change has a profound influence on the distribution,range,and richness of species. Temperature and precipitation are two indicators of climate in most of studies. Because hydrothermic factor has a significant effect on desert ecosystem,it is particularly sensitive to climate fluctuations. Rodents are especially important components of the desert ecosystem,and are dominant species that play a key role in these systems. In addition,desert rodents have played an important role in thedevelopment of ecological theory and in the understanding of adaptations to xeric environments. Therefore,understanding the response of dominant rodent species to climate change is significant to biodiversity conversion. Desert ecosystems in China,compared with similar ecosystems in other continents,suffer more disturbances from human activities. Alxa desert is a typical desert ecosystem in China. Annual mean temperatures of Alxa desert have risen 9. 05 degrees,and precipitation has increased 23. 46 mm in last decade. Against this Background,the response of desert rodents,especially dominant rodent species,to climate change,and how this response influences by human disturbances are keeping unknown. A study was conducted from 2002 to 2010 at prohibited-grazing,rotational-grazing,over-grazing,and cultivated sites to investigate the response of dominant rodent species to climate change in Alashan,Inner Mongolia,China. Rodent species were identified among and monitored with a live-trapping method. We trapped nine species including Dipus sagitta,Stylodipus andrewsi,Allactaga sibirica,Phodopus roborovskii,Cricetulus barabensis,Allocricetulus eversmanni,Meriones meridianus,Meriones unguiculatus and Spermophilus alaschanicus. M. meridianus was the dominant rodent species in prohibited-grazing and cultivated sites. However,A. sibirica and D. sagitta was the dominant rodent species in over-grazing and rotational grazing sites,respectively. The relationships of annual mean temperature and precipitation with rodent abundance were analyzed with Spearman correlation analysis and canonical correspondence analysis. The results showed that the response to temperature and precipitation was variable across rodent species. M. meridianus abundance was significantly correlated with annual precipitation in the previous year and annual mean temperature. The abundance optimum of A. sibirica and D.sagitta with respect to temperature was higher than that of M. meridianus and C. barabensis,but this pattern was reversed with respect to precipitation. Effect of temperature on desert rodent should be worked through influencing biology and ecological characteristics of animal,while precipitation affects the rodents through changing food resource and habitat.Precipitation has a pulse effect on M. meridianus abundance. These results suggested that human disturbance,occurring at a smaller spatial scale,should intensify or buffer the influence of precipitation rather than temperature on the dominant rodent species through altering food resource availability and habitat quality. These disturbances complex the response of rodent species to climate change,and have a further effect to community structure of desert rodent.