Eutrophication as a significant background problem for European wildlife
1992
Ellenberg, H. (Bundesforschungsanstalt fuer Forst- und Holzwirtschaft, Hamburg (Germany). Fachgebiet Wildtieroekologie und Jagd. Inst. fuer Weltforstwirtschaft und Oekologie)
The following view is expanded upon: conditions in the European Community (EC) have forced farms to produce increasingly more efficiently. A key factor for plant production is nitrogen (N.) In Germany, active N input on farmland has risen from about 40 kg N/ha per year during the thirties and early fifties to more than 200 kg N/ha per year at present day levels. Simultaneously, N emissions from combustion process and traffic have risen from a few to almost 40 kg N/ha per year. (NO(x)-N), an NH(x)-N emissions from intensive agriculture have grown comparably, at least regionally. This eutrophication causes many effects on agricultural ecosystems, but due to emission and deposition, significant changes can be observed almost world-wide. One easily recognizable change concerns ecosystems which are not harvested annually: Due to the unintended N-input, N is accumulated in biomass and litter. Well-nourished plants tend to begin growth earlier in the season and generally grow faster, higher and denser. This causes a shift towards more "atlantic" climatic conditions as habitat climate is changing towards more "buffered", cooler and moister conditions. This affects wildlife considerably, particulary the more sensitive young individuals. Most of these are born during late spring and early summer, when the eutrophication effects are most pronounced. Nitrogen requires the use of more herbicides, fungicides, insecticides, plant hormones and growth regulators. Refuge areas, where N is in short suppply, are disappearing - at least in part due to N emission and deposition. Better nourished plants are an attractive food source for many animals that tolerate the new microclimatic and other changes indicated above
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