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水输入。这可能是因为雾凝结在树叶上并滴到地面上，减少了光线和温度，所以蒸发的水更少，可以直接被树叶吸收。然而，目前关于雾如何影响生态系统水平衡的知识非常贫乏。这项研究量化了雾对水在墨西哥韦拉克鲁斯云雾森林地区从单个植物到整个流域的运动的影响。该项目的目标是确定云雾林向牧场的转变、松林再造林和幼林再生对河流流量的影响。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拟相结合来完成。云雾林与其他被雾/云淹没的生态系统一起，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，或受到转换和气候变化的威胁。当高大的森林被较短的植被取代时，雾-植被相互作用的丧失可能对水文平衡产生不可逆转的后果，从而影响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如何？土地利用对它们的改变呢？影响水资源。通过查明引起水量和时间变化的机制，就有可能提出具体的管理和政策建议，以保护供水和扭转退化过程。对这项研究的额外支持由水文项目（GEO）、国际科学与工程办公室、新兴前沿（BIO/OAD）和环境生物学部提供。

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.