Warming effects on arctic tundra biogeochemistry are limited but habitat‐dependent: a meta‐analysis
Warming effects on arctic tundra biogeochemistry are limited but habitat‐dependent: a meta‐analysis
复制标题
DOI：
10.1002/ecs2.3777
复制
发表时间：
2021-10
期刊：
影响因子：
2.7
通讯作者：
G. Pold;Natalie Baillargeon;Adan Lepe;E. Rastetter;S. Sistla
中科院分区：
文献类型：
--
作者：
G. Pold;Natalie Baillargeon;Adan Lepe;E. Rastetter;S. Sistla
北极苔原由不同的栖息地组成，这些栖息地在优势植被、土壤湿度和有机与无机养分循环的相对重要性方面各不相同。北极也是全球变暖最快的地区，冬季变暖占主导地位。这种变暖预计将对冻土带的碳和营养动态产生巨大影响。我们对166篇实验变暖研究论文进行了荟萃分析，以评估变暖以特定栖息地和季节的方式改变苔原生物地球化学循环的假设，以及碳(C)、氮(N)和磷(P)循环将差异加速，导致元素循环解耦的假设。研究发现，养分有效性和植物叶片化学计量学对增温的响应是可变的，总体上较弱，但植物总初级生产力和植物C库都有随增温而增加的趋势。冬季增暖对碳通量的影响没有延伸到生长季节。总体而言，尽管与氮或磷通量相比，变暖导致了更一致的碳通量增加，但生物地球化学循环解耦的证据很弱，任何影响似乎仅限于健康栖息地。然而，许多栖息地的数据过于稀疏，无法概括变暖如何使生物地球化学循环分离，而全年变暖研究也太少，无法确定变暖发生的季节是否会改变生态系统对变暖的反应。为了更好地理解驱动这种异质性的机制，确定最易受气候变暖影响的苔原栖息地、群落和土壤库，有必要开展协调的野外活动，以更有力地记录苔原栖息地对现实气候变暖情景的特定响应。
Arctic tundra consists of diverse habitats that differ in dominant vegetation, soil moisture regimes, and relative importance of organic vs. inorganic nutrient cycling. The Arctic is also the most rapidly warming global area, with winter warming dominating. This warming is expected to have dramatic effects on tundra carbon and nutrient dynamics. We completed a meta‐analysis of 166 experimental warming study papers to evaluate the hypotheses that warming changes tundra biogeochemical cycles in a habitat‐ and seasonally specific manner and that the carbon (C), nitrogen (N), and phosphorus (P) cycles will be differentially accelerated, leading to decoupling of elemental cycles. We found that nutrient availability and plant leaf stoichiometry responses to experimental warming were variable and overall weak, but that both gross primary productivity and the plant C pool tended to increase with growing season warming. The effects of winter warming on C fluxes did not extend into the growing season. Overall, although warming led to more consistent increases in C fluxes compared to N or P fluxes, evidence for decoupling of biogeochemical cycles is weak and any effect appears limited to heath habitats. However, data on many habitats are too sparse to be able to generalize how warming might decouple biogeochemical cycles, and too few year‐round warming studies exist to ascertain whether the season under which warming occurs alters how ecosystems respond to warming. Coordinated field campaigns are necessary to more robustly document tundra habitat‐specific responses to realistic climate warming scenarios in order to better understand the mechanisms driving this heterogeneity and identify the tundra habitats, communities, and soil pools most susceptible to warming.