Ecohydrological Controls on Watershed Response to Land Use Change in the Montane Cloud Forest Zone in Central Veracruz, Mexico

一年中大部分时间被雾或薄雾覆盖的生态系统可能对供水至关重要，因为雾的存在会增加总的水输入。这可能是因为雾凝结在树叶上并滴落到地面，降低了光线和温度，因此蒸发的水分更少，可以被树叶直接吸收。然而，目前关于雾如何影响生态系统水平衡的知识极其贫乏。这项研究量化了雾对墨西哥韦拉克鲁斯云雾林区通过单个植物向整个流域的水分运动的影响。该项目的目标是确定云雾林还草、松树更新造林和幼林更新对径流的影响。这将通过将水文、生态生理、大气和土壤过程的实地测量与流域模型相结合来实现。云雾森林与其他雾/云淹没的生态系统相结合，在地球上占据了7000多万公顷的土地，但许多森林已经被砍伐，或者受到气候变化的威胁。当高大的森林被矮小的植被取代时，雾-植被相互作用的丧失可能会对水文平衡造成不可逆转的后果，从而影响到低洼地区主要人口中心的供水。这项研究填补了目前对云雾森林及其土地利用变化如何影响水资源的理解的一个重要空白。通过确定引起水量和时间变化的机制，将有可能为保护供水和扭转退化进程提出具体的管理和政策建议。水文学计划(GEO)、国际科学与工程办公室、新兴前沿(BIO/OAD)和环境生物学分部正在为这项研究提供额外的支持。

Ecosystems that are covered in fog or mist for much of the year may be critical for water supply because the presence of fog can increase total water inputs. This can occur because fog condenses on tree leaves and drips to the ground, reduces light and temperature so less water evaporates, and can be directly absorbed by leaves. However, current knowledge about how fog influences ecosystem water balance is extremely poor. This research quantifies the effect of fog on water movement through individual plants to entire watersheds in a cloud forest zone in Veracruz, Mexico. The goal of this project is to determine how conversion of cloud forest to pasture, pine reforestation, and young regenerating forest affects streamflow. This will be accomplished by combining field measurements of hydrological, ecophysiological, atmospheric and soil processes with watershed modeling. Cloud forests, combined with other fog/cloud inundated ecosystems, occupy over 70 million hectares on earth, yet many have already been deforested or are threatened by conversion and climate change. Loss of fog-vegetation interactions when tall forests are replaced by shorter vegetation may have irreversible consequences for the hydrological balance, thereby affecting water supply to major population centers in lower-lying regions. This research fills an important gap in current understanding of how cloud forests?and their alteration by land use?affect water resources. By identifying the mechanisms that cause changes in water flow amounts and timing, it will be possible to make specific management and policy recommendations for protecting water supply and reversing processes of degradation. Additional support for this research is being provided by the Hydrology Program (GEO), the Office of International Science & Engineering, Emerging Frontiers (BIO/OAD), and the Division of Environmental Biology.