Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA.
Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, USA.
Sci Adv. 2018 May 23;4(5):eaaq0942. doi: 10.1126/sciadv.aaq0942. eCollection 2018 May.
Current models of ecosystem development hold that low nitrogen availability limits the earliest stages of primary succession, but these models were developed from studies conducted in areas with temperate or wet climates. Global warming is now causing rapid glacial retreat even in inland areas with cold, dry climates, areas where ecological succession has not been adequately studied. We combine field and microcosm studies of both plant and microbial primary producers and show that phosphorus, not nitrogen, is the nutrient most limiting to the earliest stages of primary succession along glacial chronosequences in the Central Andes and central Alaska. We also show that phosphorus addition greatly accelerates the rate of succession for plants and for microbial phototrophs, even at the most extreme deglaciating site at over 5000 meters above sea level in the Andes of arid southern Peru. These results challenge the idea that nitrogen availability and a severe climate limit the rate of plant and microbial succession in cold-arid regions and will inform conservation efforts to mitigate the effects of global change on these fragile and threatened ecosystems.
当前的生态系统发展模型认为，氮的可利用性限制了初级演替的最早阶段，但这些模型是根据在温带或湿润气候地区进行的研究开发的。全球变暖现在甚至导致内陆寒冷干旱地区的冰川迅速消退，而这些地区的生态演替尚未得到充分研究。我们结合了对植物和微生物初级生产者的野外和微宇宙研究，结果表明，在中安第斯山脉和阿拉斯加中部的冰川年代序列中，限制初级演替最早阶段的关键养分是磷，而不是氮。我们还表明，即使在海拔超过 5000 米的秘鲁南部干旱寒冷地区的最极端冰川消退点，添加磷也能大大加快植物和微生物光合生物的演替速度。这些结果挑战了氮的可利用性和恶劣气候限制寒冷干旱地区植物和微生物演替速度的观点，并为减轻全球变化对这些脆弱和受威胁生态系统的影响的保护工作提供了信息。
