Homogenisation of ECosystem functioning between Temperate and Neotropical streams due to AgRicultural land usE (HECTARE)

农业区的扩大和集约化以及与之相关的森林砍伐、富营养化和生境异质性的改变仍然是全世界生态系统运行的最重要的压力来源。关键环境特征的改变可能导致不同气候区河流特有的功能属性的丧失，并最终可能导致河流生态系统功能的同质化。以前的研究大多局限于特定生物群中的单一功能，缺乏对气候区之间以农业为驱动的河流生态系统功能同质化的潜力的透彻了解。项目公顷分析了位于德国哈兹和巴西塞拉多和大西洋森林的原始和农业溪流的生态系统功能。通过量化食物网和测量生态系统生产力和呼吸的新组合，公顷提供了对温带和新热带河流的能量和物质通量的机械理解，包括它们与集水区的营养耦合。在此基础上，将确定受农业土地利用影响的全生态系统物质和能量通量的关键路径。建议的以公顷为单位的生物群间办法将综合与农业土地利用有关的影响模式，并分析河流生态系统的功能同质化程度。

The expansion and intensification of agricultural areas and the associated deforestation, eutrophica-tion and modification of habitat heterogeneity remain the most important stressors to stream ecosys-tem functioning worldwide. The alteration of key environmental characteristics may cause the loss of functional attributes specific for streams in different climate zones and may ultimately lead to a ho-mogenisation of stream ecosystem functioning. Previous studies were mostly restricted to a single function in a particular biome and a thorough understanding on the potential for an agriculturally driven functional homogenisation of stream ecosystems among climate zones is lacking. The project HECTARE analyses ecosystem functioning of pristine and agricultural streams situated in the German Harz and in the Brazilian Cerrado and Atlantic forest. By the novel combination of quantification of food webs and measurements of ecosystem productivity and respiration, HECTARE delivers a mech-anistic understanding on energy- and matter fluxes in temperate and Neotropical streams including their trophic coupling to the catchments. Building on that, key pathways of whole-ecosystem matter and energy fluxes that are impacted by agricultural land use will be identified. The inter-biome ap-proach proposed with HECTARE will allow for a synthesis of impact patterns associated with agricul-tural land use and an analysis of the degree of functional homogenisation of stream ecosystems.