Quantification of functional hydro-biogeochemical indicators in Ecuadorian ecosystems and their reaction on global change

水是生态系统的内在组成部分，是颗粒和溶解营养物质横向运输的关键因素，迫使能量转移，引发侵蚀，并推动生物多样性模式。鉴于土地利用和气候变化对任何这些组成部分的巨大影响以及厄瓜多尔生态系统的脆弱性，需要指标来描述这些生态系统的结构状况，捕捉这些生态系统的功能关系和过程。作为该项目扩展的一部分，我们力求完成一套来自水文和生物地球化学领域的功能指标的开发，为选定的环境定制。所研究的指标描述了(1)水流形式和时间，(2)养分循环和通量，以及(3)泥沙通量。为了评估水流状态和时间，我们集中研究了稳定的水同位素，以估计可能受到降雨模式和土地利用变化影响的平均传输时间分布。硝酸浓度的迟滞回线和频率分析已被确定为监测养分通量的合适功能指标。它们最有可能受到温度变化以及土地利用和管理的影响。最后，测量的泥沙通量表明地表径流对总流量的贡献，主要受降雨强度和土地利用的影响。在目前的项目阶段，建立了两个水文-生物地球化学监测网（Páramo和热带山地雨林），并与厄瓜多尔的对应部门密切合作维持这些监测网。这些网络为检验选定的指标提供数据。对于(1)，我们每周在河流、土壤和降水中选择稳定的水同位素样本，而对于(2)和(3)，我们以高时间分辨率自动记录沉积物和硝酸盐浓度。作为项目扩展的一部分，我们将完成拟议功能指标的制定，并对全球变化下选定的指标进行基于模型的评估。然后，将分析开发的全球变化情景以及结合水文模型CMF和考虑营养和碳通量的生物地球化学模型的定制模型设置，以捕获功能指标的可能反应。最后，与我们的大学和非大学合作伙伴一起，我们将为制定生物多样性和生态系统功能综合监测计划的书面指导方针做出贡献。

Water is an intrinsic component of ecosystems acting as a key agent of lateral transport for particulate and dissolved nutrients, forcing energy transfers, triggering erosion, and driving biodiversity patterns. Given the drastic impact of land use and climate change on any of these components and the vulnerability of Ecuadorian ecosystems, indicators are required that describe the structural condition, capture the functional relations of and processes within those ecosystems. As part of this project extension we seek to complete the development of a set of functional indicators from the fields of hydrology and biogeochemistry customized for the selected environments. The investigated indicators describe (1) flow regime and timing, (2) nutrient cycling and flux rates, and (3) sediment fluxes.For assessing flow regime and timing we concentrated on studying stable water isotopes to estimate mean transit time distributions, that are likely to be impacted by changes in rainfall patterns and land use. Hysteresis loops and frequency analysis of nitrate concentrations have been identified as suitable functional indicators to monitor nutrient fluxes. They are most likely to be altered by changes in temperature as well as by land use and management. Finally, measured sediment fluxes indicate surface runoff contribution to total discharge, mainly influenced by the intensity of rainfall as well as land use.In the current project phase two hydro-biogeochemical monitoring networks (Páramo and tropical mountain rainforest) were established and are maintained in close cooperation with our Ecuadorian counterparts. Those networks supply the data for testing the selected indicators. For (1) we select weekly stable water isotopes samples in stream, soil and precipitation water, while for (2) and (3) we automatically record the sediment and nitrate concentrations in a high temporal-resolution.As part of this project extension, we will complete the development of the proposed functional indicators and conduct a model-based evaluation of the selected indicators under global change. The developed global change scenarios together with a tailored model setup combining the hydrological model CMF and a bio-geochemical model accounting for nutrient and carbon fluxes, will then be analyzed to capture the likely reaction of functional indicators. Finally, together with our university and non-university partners we will contribute to the written guidelines for developing a comprehensive monitoring program for biodiversity and ecosystem functions.