Homogenisation of ecosystem functioning between temperate and neotropical streams due to agricultural land use (HECTARE)


The expansion and intensification of agricultural production, has along with the associated deforestation, eutrophication and modification of habitat heterogeneity, remained the most important stressors to stream ecosystem functioning worldwide. The alteration of key environmental characteristics may cause the loss of functional attributes specific to streams in different climatic zones and may ultimately lead to a homogenisation of stream ecosystem functioning. Previous studies were mostly restricted to a single function in a particular biome, and as result a thorough understanding of 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 Mountains 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 mechanistic 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 approach proposed with HECTARE will allow for a synthesis of impact patterns associated with agricultural land use and an analysis of the degree of functional homogenisation of stream ecosystems.


Federal University of São João Del-Rei, Dept. of Geosciences


Deutsche Forschungsgemeinschaft DFG (Grant no. BR 4358/1-1)