LTER IV: Jornada Basin: Linkages in Semi-arid Landscapes

奇瓜瓦沙漠景观体现了全球半干旱地区的生态条件、脆弱性和管理问题。Jornada盆地长期生态研究项目的目标是确定控制半干旱景观生态系统动态的关键因素，以了解荒漠化的原因和后果。以往的LTER工作主要集中在单一植物空间的尺度上，以及在该尺度上土壤资源的再分配。然而，半干旱区的固有性质，包括在地形变化很大的景观中盛行的大风和短时强降水事件，促进了物质在更大尺度上的再分配。LTER阶段的中心假设是景观位置和景观单元之间的联系对场地内的生态系统动态和生物模式产生重要影响。我们建议以几种方式建立我们对植物空间尺度上资源再分配的理解。我们将综合现有的长期数据与景观单元之间联系的新研究，我们将进行模拟建模工作，以测试单元内与单元之间过程的相对重要性。我们将启动或扩大对水、养分和生物的景观通量的研究，以评估在这种规模下影响生态系统动态的关键过程。我们还将利用遥感在更大的空间尺度上评估通量和过程。跨站点研究将用于测试我们的假设的一般性，以应用于半干旱生态系统和荒漠化景观的管理和赎回。

Chicuahuan Desert landscapes exemplify the ecological conditions, vulnerability and management issues found in semi-arid regions around the globe. The goal of the Jornada Basin Long-Term Ecological Research program is to identify the key factors that control ecosystem dynamics in semi-arid landscapes, with the objective of understanding the causes and consequences of desertification. Pervious LTER work focused primarily at the scale of a single plant-interspace and on the redistribution of soil resources at that scale. However, the intrinsic nature of semi-arid regions, including the prevalence of high winds and short intense precipitation events in landscapes with substantial topographic variability, promotes the redistribution of materials at larger scales. The central hypothesis of the LTER phase is that landscape position and linkages among landscape units exert important influences on ecosystem dynamics and biotic patterns within sites. We propose to build on our understanding of resource redistribution at the plant-interspace scale in several ways. We will synthesize existing long-term data with new studies on linkages among landscape units, and we will conduct simulation modeling efforts to test the relative importance of within- versus between-unit processes. We will initiate or expand studies of landscape fluxes of water, nutrients, and organisms in order to evaluate key processes affecting ecosystem dynamics at this scale. We will also employ remote sensing to assess fluxes and processes at larger spatial scales. Cross-site studies will be used to test the generality of our hypotheses for application to management and redemption of semi-arid ecosystems and desertified landscapes.