DISSERTATION RESEARCH: Climate change and biome range shifts at high elevations

生态学家早就认识到，气候变量(如温度或降雪量)在决定物种和群落类型的地理范围方面发挥着关键作用。因此，随着气候变化导致我们的星球变暖，这些范围预计将向两极和上坡移动。然而，一个复杂的因素是，非气候变量(如土壤质量)也会影响生物范围以及生物对气候变化的反应速度。这项研究的目的是了解气候和非气候限制对雷尼尔山国家公园高度多样化的山地草甸群落未来分布的重要性。据预测，气候变暖将导致这些草甸向上移动，但有两个因素可能会限制这种移动的速度。首先，草甸植物可能无法以通过变暖而变得可用的速度将种子分散到新的合适的栖息地(“扩散限制”)。其次，幼苗可能不能在高海拔的岩石和贫瘠的土壤中生根(“生根限制”)。为了更好地了解这些草甸将如何应对气候变化，研究人员将：1)使用气候数据和统计模型来预测未来在给定气候变化和假设没有非气候限制的情况下，草甸将出现在哪里；2)通过监测种子从母体植物移走的距离来量化传播限制；以及3)通过比较雷尼尔山肥沃和贫瘠土壤中的植物表现来量化建立限制。气候变化可能会导致世界各地物种和群落的重新洗牌，改变人类赖以生存的生态系统。这项研究将提高我们对山地草甸将如何应对气候变化的科学理解，这是准备和缓解气候变化负面影响的关键一步。由于研究人员与雷尼尔山公园的管理者分享了研究结果，这项研究将直接为当地的管理决策提供信息。此外，研究人员定期与K-12学生、本科生和公园游客交流他们的结果。

Ecologists have long recognized that climate variables (such as temperature or snowfall) play a key role in determining the geographic ranges of species and types of communities. Thus, as our planet becomes warmer due to climate change, these ranges are expected to shift toward the poles and uphill. However, a complicating factor is that non-climatic variables (such as soil quality) also influence biological ranges and how rapidly organisms can respond to climate change. The goal of this research is to understand the importance of both climatic and non-climatic constraints on the future distribution of the highly diverse mountain meadow community at Mount Rainier National Park. Warming is predicted to result in an upward movement of these meadows, but two factors could constrain the rate at which this occurs. First, meadow plants may not be able to disperse seeds into newly suitable habitat at the rate it becomes available through warming ("dispersal limitation"). Second, seedlings may not be able to establish in the rocky and infertile soils present at higher elevations ("establishment limitation"). To develop a better understanding of how these meadows will respond to climate change the researchers will: 1) use climate data and statistical models to predict where meadows will occur in the future given climate change and assuming no non-climatic limitations; 2) quantify dispersal limitations by monitoring the distance that seeds are moved from parent plants; and 3) quantify establishment limitations by comparing plant performance in fertile versus infertile soils at Mount Rainier.Climate change will likely cause a reshuffling of species and communities around the world, transforming the ecosystems humans depend on. This study will improve our scientific understanding of how mountain meadows will respond to climate change, a critical step in preparing for and alleviating the negative effects of climate change. Because the researchers share results with Park managers at Mount Rainier, this research will directly inform local management decisions. Moreover, the researchers regularly communicate their results with K-12 students, undergraduates, and Park visitors.