Comparative Responses of Moist and Dry Arctic Tundra to Altered Snow and Temperature Regimes

9400083沃克这个项目将通过冬季降水和夏季温度的实地操作，评估气候变化在潮湿和干燥的北极苔原上的生态后果。项目科学家将研究对物种性能、群落结构以及生态系统碳和氮动态的影响。他们将竖起积雪栅栏以增加积雪，并使用小型温室来温暖空气和土壤温度。木本植物的生长年轮和年茎生长量以及生理植物的表现将与历史的温度和降水记录进行比较。实验结果还将与沿积雪梯度的自然植被模式和出现长期人为增加积雪的地区进行比较。模拟建模将用于扩展他们的发现，重点放在净生态系统碳收支上。主要工作将是量化和了解北极冻土带对一系列气候变化情景的瞬时反应的规模和方向。实验基础设施将允许其他调查人员在未来几年进行更详细的调查，如果响应如我们预期的那样具有足够的规模，对评估气候变化对北极生态系统的影响具有重要意义。该项目是美国对国际苔原实验(ITEX)的贡献。***

9400083 Walker This project will evaluate the ecological consequences of climate change in moist and dry arctic tundra with field manipulations of winter precipitation and summer temperature. Project scientists will investigate effects on species performance, community structure, and ecosystem C and N dynamics. They will erect snow fences to increase snowpack and use small greenhouses to warm air and soil temperatures. Growth rings and annual stem increments of woody species and physiological plant performance will be compared with historical temperature and precipitation records. Experimental findings will also be compared to natural vegetation patterns along snow gradients and areas where long-term anthropogenic increases in snow cover have occurred. Simulation modeling will be used to extend their findings with a focus on net ecosystem carbon budgets. The main effort will be to quantify and understand the magnitude and direction of the transient response of arctic tundra to a series of climate change scenarios. The experimental infrastructure will permit more detailed investigations by other investigators in future years if the response is, as we anticipate, of sufficient magnitude to be of importance for evaluating effects of climate change to arctic ecosystems. The project is a U.S. contribution to the International Tundra Experiment (ITEX). ***