Gardner Janet L, Heinsohn Robert, Joseph Leo
Department of Botany & Zoology, Research School of Biology, Australian National University, Canberra, Australia.
Proc Biol Sci. 2009 Nov 7;276(1674):3845-52. doi: 10.1098/rspb.2009.1011. Epub 2009 Aug 12.
Intraspecific latitudinal clines in the body size of terrestrial vertebrates, where members of the same species are larger at higher latitudes, are widely interpreted as evidence for natural selection and adaptation to local climate. These clines are predicted to shift in response to climate change. We used museum specimens to measure changes in the body size of eight passerine bird species from south-eastern Australia over approximately the last 100 years. Four species showed significant decreases in body size (1.8-3.6% of wing length) and a shift in latitudinal cline over that period, and a meta-analysis demonstrated a consistent trend across all eight species. Southern high-latitude populations now display the body sizes typical of more northern populations pre-1950, equivalent to a 7 degrees shift in latitude. Using ptilochronology, we found no evidence that these morphological changes were a plastic response to changes in nutrition, a likely non-genetic mechanism for the pattern observed. Our results demonstrate a generalized response by eight avian species to some major environmental change over the last 100 years or so, probably global warming.
陆生脊椎动物的种内纬度渐变群现象，即同一物种的成员在高纬度地区体型更大，这一现象被广泛解释为自然选择和对当地气候适应的证据。预计这些渐变群会随着气候变化而发生变化。我们利用博物馆标本测量了澳大利亚东南部大约过去100年中8种雀形目鸟类的体型变化。其中4种鸟类的体型显著减小（翅长的1.8 - 3.6%），且在此期间纬度渐变群发生了变化，一项荟萃分析表明所有8种鸟类都呈现出一致的趋势。现在，南部高纬度地区的种群呈现出1950年前更靠北种群的典型体型，相当于纬度移动了7度。通过羽毛年代学，我们没有发现证据表明这些形态变化是对营养变化的可塑性反应，而营养变化是观察到的这种模式可能的非遗传机制。我们的结果表明，在过去约100年里，8种鸟类对某种重大环境变化产生了普遍反应，可能是全球变暖。
