Collaborative Research: On Topographic Imprint of Hillslope Aspect: Deciphering Aspect Controls on Vegetation and Landforms in Central New Mexico

本项目将研究坡向和植被在新墨西哥州中部沙漠高程中对景观演化速率和过程的调节作用，其中坡向在生态系统结构中起主导作用。研究了半干旱生态系统中植被模式对径流和侵蚀的影响，特别是在美国西南部的长期生态研究点。研究已经确定了植被变化对景观规模影响的关键问题，并产生了可检验的假设。然而，植被-侵蚀相互作用对产沙量和地貌演变的长期影响尚未得到充分的记录和模拟。这项研究将研究新墨西哥州中部（塞维利亚国家野生动物保护区的西北部）的中低起伏集水区，那里朝北的山坡上有杜松草稀树草原，朝南的山坡上有灌木丛，其他因素，如降水、岩性和海拔相对均匀。该遗址现有的植被模式被认为自全新世中期以来就存在，在此之前，松树-杜松-橡树林地主导了该地区。在地形和对季风降水的生态水文响应方面，站点内相对的山坡在形态上表现出普遍的差异，朝北的山坡通常比朝南的山坡更陡峭、更平坦。这项工作将研究土壤、植被和地形的共同演变，使用各种基于过程的研究方法，包括生态水文监测（土壤湿度、径流、蒸散发、生物量）；地表沉积物测年以近似全新世侵蚀速率；生态水文和景观演变的数值模拟。更广泛的影响：该项目将培养两名研究生。两个机构将联合开发一个项目网站，报告研究成果、数据和数值模型实验的可视化。这项跨学科的研究将对塞维利亚国家野生动物保护区正在进行的生态系统监测研究产生重大影响。特别是，我们的建模方法将提供预测生物群落过渡和土地利用变化对区域水文和沉积物产量的影响的能力。这种建模工作对美国西南部以及全球其他半干旱地区的栖息地保护、恢复和土地利用规划工作至关重要。

Collaborative Research: On Topographic Imprint of Hillslope Aspect: Deciphering Aspect Controls on Vegetation and Landforms in Central New Mexico This project will investigate the role of aspect and vegetation in modulating rates and processes of landscape evolution in desert elevations of central New Mexico, where aspect plays a dominant role on ecosystem structure. The influence of vegetation patterns on runoff and erosion have been studied in semiarid ecosystems, especially in the Long Term Ecological Research sites in the southwest US. Research has identified critical concerns about the landscape scale impacts of vegetation change, and resulted in testable hypotheses. Yet, long-term implications of vegetation-erosion interactions on sediment yields and landform evolution have not been adequately documented and modeled. This research will study moderate- to low-relief catchmets in central New Mexico (northwest part of the Sevilleta National Wildlife Refuge), where north-facing slopes are characterized by a juniper-grass savanna, and south-facing slopes by shrublands, with other factors such as precipitation, lithology, and elevation are relatively uniform. Existing vegetation patterns in this site are believed to have been present since the mid Holocene, before which pinon-juniper-oak woodlands dominated the region. The opposing hillslopes in the site show pervasive differences in their morphologies with north-facing slopes usually steeper and more planar than south-facing slopes, and in their ecohydrological response to monsoon precipitation. This work will investigate the co-evolution of soils, vegetation and topography using a variety of process-based research methods including ecohydrological monitoring (soil moisture, runoff, evapotranspiration, biomass); dating of surface sediments to approximate Holocene erosion rates; and numerical modeling of ecohydrology and landscape evolution. Broader Impacts: This project will train two graduate students. A project website will be jointly developed between the two institutions, reporting research results, data, and visualization of numerical model experiments. This interdisciplinary research will have a significant impact on the ongoing efforts in ecosystem monitoring studies in the Sevilleta National Wildlife Refuge. In particular, our modeling approach will offer capabilities in predicting the impacts of biome transition and land-use change on regional hydrology and sediment yields. Such modeling efforts are of critical importance in habitat conservation, restoration, and land-use planning efforts across the southwest US as well as in other semiarid regions worldwide.