大熊猫是我国特有珍稀濒危动物，被誉为“活化石”、“和平使者”和“外交使节”。由于受天然屏障（如大江大河）、栖息地破碎化和大型工程建设的影响，其野生种群被分割成20多个小种群，特别是相岭山系被分割得最为严重。
中科院动物研究所魏辅文研究员领导的研究组近年来一直致力于“栖息地破碎化将如何影响大熊猫孤立小种群的遗传结构及种群生存力”的研究，他们采用非损伤性遗传方法，发现小相岭大熊猫孤立小种群曾发生过严重的崩溃，种群数量从清康乾盛世开始剧烈下降，这与清朝时期的政策激励人口数量剧增所导致的土地开垦、森林砍伐加剧致使大熊猫栖息地严重丧失密切相关（Conservation Biology，2010）。
他们进一步对大、小相岭地区大熊猫的种群历史与空间遗传结构进行了分析，发现大渡河阻隔了大熊猫种群间的基因流，导致小相岭和大相岭为不同的遗传基因簇；而近现代公路（108国道）限制了道路两侧大熊猫种群间的基因流。
大熊猫为具有较强扩散能力的大型食肉目动物，传统观点认为河流和公路可能不会对其扩散构成障碍。但本研究却表明，大渡河是影响大熊猫扩散的天然屏障，而108国道是为近期物理障碍，揭示大江大河与公路是塑造大熊猫种群空间遗传格局的重要因素。结合大熊猫个体的空间遗传分布与生境适宜度等信息，该研究还确定了两条最佳廊道建设区域，相关建议已被相关管理部门采纳，这将为大、小相岭地区大熊猫小种群的长期存活提供有力保障。该研究成果于近期在线发表于分子生态学主流期刊Molecular Ecology。（生物谷Bioon.com）
生物谷推荐原文出处：
Molecular Ecology, doi: 10.1111/j.1365-294X.2011.04999.x.
Significant genetic boundaries and spatial dynamics of giant pandas occupying fragmented habitat across southwest China
LIFENG ZHU1, SHANNING ZHANG2, XIAODONG GU3, FUWEN WEI1
Keywords:conservation;genetic boundaries;giant pandas;habitat fragmentation;spatial dynamics
Abstract
Understanding population history and genetic structure are key drivers of ecological research. Here, we studied two highly fragmented and isolated populations (Xiaoxiangling and Daxiangling) of giant pandas (Ailuropoda melanoleuca) at the extreme southwestern edge of their distribution. This area also contains the Dadu River, national road 108 and various human infrastructure and development, providing an ideal region in which we can identify the effects of different barriers on animal movements. We used partial mitochondrial control region (mtDNA) and nine microsatellite loci (nuclear DNA) data derived from 192 faecal and one blood sample collected from the wild. We found 136 genotypes corresponding to 53 unique multilocus genotypes and eight unique control region haplotypes (653 bp). Significant genetic boundaries correlated spatially with the Dadu River (K = 2). We estimate that a major divergence took place between these populations 26 000 years bp, at around the similar time the rock surface of valley bottom formed in Dadu River. The national road has resulted in further recent population differentiation (Pairwise FS on mtDNA and nuclear DNA) so that in effect, four smaller sub-populations now exist. Promisingly, we identified two possible first-generation migrants and their migration paths, and recommended the immediate construction of a number of corridors. Fortunately, the Chinese government has accepted our advice and is now planning corridor construction.
