School of Plant Biology, The University of Western Australia, Crawley, WA 6009, Australia.
Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancon, Republic of Panama.
Science. 2014 Sep 26;345(6204):1602-5. doi: 10.1126/science.1256330.
The mechanisms that shape plant diversity along resource gradients remain unresolved because competing theories have been evaluated in isolation. By testing multiple theories simultaneously across a >2-million-year dune chronosequence in an Australian biodiversity hotspot, we show that variation in plant diversity is not explained by local resource heterogeneity, resource partitioning, nutrient stoichiometry, or soil fertility along this strong resource gradient. Rather, our results suggest that diversity is determined by environmental filtering from the regional flora, driven by soil acidification during long-term pedogenesis. This finding challenges the prevailing view that resource competition controls local plant diversity along resource gradients, and instead reflects processes shaping species pools over evolutionary time scales.
塑造植物沿着资源梯度的多样性的机制仍然没有得到解决，因为竞争理论是孤立地进行评估的。通过在澳大利亚生物多样性热点地区的一个超过 200 万年的沙丘年代序列中同时测试多个理论，我们表明，植物多样性的变化不能用局部资源异质性、资源分区、养分化学计量或沿这个强烈资源梯度的土壤肥力来解释。相反，我们的结果表明，多样性是由区域植物群的环境过滤决定的，这是由长期成土过程中的土壤酸化驱动的。这一发现挑战了普遍认为的资源竞争控制沿资源梯度的本地植物多样性的观点，而是反映了在进化时间尺度上塑造物种库的过程。
