FOR 816: Biodiversity and Sustainable Management of a Megadiverse Mountain Ecosystem in South Ecuador
Zusammenfassung der Projektergebnisse
It is undisputed that the tropical forest, its biodiversity, ecosystem functioning and services are under great threat due to environmental changes, particularly as a result of climate and land use change. This also holds for the tropical mountain forest of the south-eastern Ecuadorian Andes which harbours the second hottest biodiversity hotspot of vascular plants worldwide. Particularly non-sustainable land use strategies as the conversion of natural forest to pasture and arable land are the main drivers of a severe environmental deterioration in this valuable hotspot area. Previous work in the San Francisco valley breaching the southeastern Andes of Ecuador had shown that particularly the invasion of pastures by an aggressive weed, the southern bracken, leads to the abandonment of formerly productive pasture land, mainly due to the inability of the local farmers to properly control bracken succession. As a result, their current strategy is to cut new natural forest by slash-and-burn activity, with this, boosting the downward spiral of a progressing land deterioration. This alarming situation was the starting point of the research unit FOR816 “Biodiversity and Sustainable Management of a Megadiverse Mountain Ecosystem in South Ecuador“. Based on comparative ecological surveys (comparison of natural forest and the anthropogenic pasture replacement system), the successful establishment of interdisciplinary ecological experiments and the adaption and development of related numerical models, the main aim of the FOR816 was to develop science-directed and sustainable land use and management portfolios which at the same time warrant the preservation of biodiversity, ecosystem functions, processes and services, (ii) which include rehabilitation options to recover attenuated diversity and lost usability, and (iii) which guarantee a better livelihood for the local population. Because of the highly complex and to a great extent still unknown (species to functions) system, another main aim required to properly address the main objective was to gain a deep scientific understanding of ecosystem functioning in both manifestations of the ecosystem and in particular, of the interrelations between biodiversity, the biogeochemical cycle and local/global human activity. Consequently, the research unit FOR816 was designed as a truly interdisciplinary endeavour bundling the expertise of biology, geoscience, forestry, computer sciences and socio-economic disciplines. The main results provided deep insights into the environmental controls (past, present and future) of the ecosystem regarding climate, hydrology, geomorphology and soil. Hitherto unkown climatic mechanisms regarding rainfall formation could be found, as also an unexpected hydrological behaviour of the subcatchments in the Rio San Francisco valley. It was finally shown that the interaction between topography, climate, soil and vegetation leads to a moderate disturbance system, most likely an important local driver for the megadiversity of the area. Regarding environmental changes, climate change could be confirmed also affecting the area, but particularly forest destruction at alarming rates was observed, with negative consequences on most ecosystem regulatory functions. The impacts of atmospheric nutrient deposition, mainly caused by Amazon biomass burning, on the biogeochemical cycle was intensively investigated, showing an unexpectedly fast response of the ecosystem to moderate nutrient additions which reveals a high vulnerability of the nutrient-poor mountain forest by still moderate eutrophication. By analysing above and below ground reactions of organisms and trophic networks it became clear, how complex functional relations in the natural mountain forst were shaped. The analysis of sustainable land use options, particularly the control of bracken and the ability of afforestation with indigenous trees on the pasture side gave deep insights in the successful strategy of the weed, but also in the ecological suitability of local trees for afforestation. The combined and bundled interdisciplinary knowledge gain finally allowed the consortium to formulate science-driven recommendations for sustainable land use options including the intensification of pasture management and afforestation, mainly with the local alder tree. Furthermore, a novel assessment scheme for the rehablitation of abandoned farm land could be developed and tested, combining ecological, economic and social indicators. Regarding structural aspects, the research unit was exceptionally successful in promoting young scientists, capacity building and developing the transfer of knowledge, gained by basic research activities, to prototype applications, thus serving the local community at site, which is fundamental for a successful environmental research in developing countries.
