Spatial and temporal separation of biogeochemical conversion processes E 3.2 123 E 3.2.6 Spatial and temporal separation of biogeochemical turnover processes in ecosystems: The future With the start ofthe Industrial Revolution, not only was it possible to acquire larger quantities of fossil and renewable raw materials more efficiently, but their transport over long distances also became much easier (ships, railways, trucks). However, as a result ofthe improved transport possibilities, the spatial and temporal separation ofthe biogeochemical turnover processes was further accelerated and extended to a global dimension. In addition to the substances bound up with biomass, gases such as CO 2 ,NH 3 ,NO x and SO 2, were now emitted at higher levels, resulting in a direct or indirect impact on the biosphere and pollution of inland waters and shallow seas in coastal areas, as a result of sewage from built-up areas and agriculture (Paerl, 1993). Since most inland waters are phosphorus-limited, phosphorus-rich sewage and sediments make an especially high contribution to eutrophication.Whereas the eutrophication of inland lakes has considerably fallen in the industrialized countries as a result of improved wastewater treatment andthe substitution of phosphates in detergents, the problem is becoming much worse in developing countries due to population growth andthe intensification of agriculture (Section E 2.3) The dense transport network on landand water and in the air allows the transport of very large quantities of raw materials and food from all parts ofthe world into the industrialized countries. Fig. E 3.2-2 shows the proportion of nitrogen used by the import of fodder to EU agriculture. The exporting countries thus suffer constant biogeochemical depletion (the loss of phosphate is especially serious) and, as a consequence, the acidification ofthe soils, which is in contrast to a situation of ecologically unsound biogeochemical accumulation in the industrialized countries. Wilhelm Busch illustrated this phenomenon very aptly in his picture story Maler Klecksel (Painter Splodge) (Fig. E 3.2-3). Another threatening trend can be seen in the developing countries: the rapid emergence of megacities is often linked to a rapid neglect ofthe rural areas. People’s material need in rural areas leads to serious symptoms of ecosystem degradation, whereas in the built-up areas the uncontrolled accumulation of waste is leading to eutrophication, is poisoning soils and water bodies and is pushing out the characteristic communities of organisms. The geographical separation of chemical turnover processes on the mainland leads to an increase in nutrient inputs into water bodies. In this respect, the natural eutrophication described above is exceeded by several powers of ten (WBGU, 1998a).As a result ofthe deterioration ofthe living conditions there is a reduction in biological diversity, usable fish populations are put at risk and other water functions are impaired. Viewed in terms of biogeochemical cycles, the ‘recipient regions’ have developed into flowthrough systems by decoupling cycles at the expense of ‘donor regions’. In the process, large quantities of exhaust gases, wastewater and solid waste arise that pollute and change the environmental media that surround them. The order of magnitude reached by human influence can be seen in the global chemical conversion of nitrogen and sulphur, which are already dominated by man, and in the key changes to the carbon and phosphorus cycles. Figure E 3.2-2 Feedstuff imports into the European Union in 1997. Source: Mund, 1999 Netherlands Malta Belgium 106.9 123.7 181.6 Denmark 59.6 Ireland Germany United Kingdom Portugal Austria France Europe 20.1 15.4 15.3 12.5 12.5 11.9 10.8 0 50 100 150 200 Fodder imports [kg N ha -1 year -1 ]
124 E Diversity of landscapes and ecosystems ever-closer global links, greater attention needs to be paid to this issue at national and international level. At the international level, UNEP could take on the requisite coordination tasks. E 3.3 Sustainable land use E 3.3.1 Types of landscape use Hier thront der Mann auf seinem Sitze Und ißt z.B. Hafergrütze. Der Löffel führt sie in den Mund, Sie rinnt und rieselt durch den Schlund, Sie wird, indem sie weiterläuft, Sichtbar im Bäuchlein angehäuft.– So blickt man klar wie selten nur, Ins innre Walten der Natur. Figure E 3.2-3 ‘Painter Splodge’ as a decoupled system. Source: Wilhelm Busch, 1884 The knowledge about the effects ofthese interventions in ecosystem chemical conversion processes is essentially available, but so far it has not been sufficiently evaluated or translated into political action at a local or global level. There is a need for urgent clarification as to the extent to which the evident or latent disproportion of biogeochemical fluxes and stocks leads to intolerable changes of biodiversity and its associated functions. Furthermore, preventive and compensatory strategies have to be developed and used that mainly aim at closing biogeochemical cycles. Economic practices that are based on the overexploitation of natural or managed ecosystems shall be avoided on all levels (Chapter G). Management directed towards sustainable use should be identified by labelling schemes or promoted via other measures in order to offset the higher costs incurred by these strategies. Education must engender an awareness that the sustainable use of terrestrial and aquatic ecosystems has its price. A further instrument for avoiding materialrelated changes in biological diversity is the development of bioregional management (Section E 3.9), with the help of which geographical disparities can be reduced and regional cycles strengthened. In order to preserve the necessary scope for action for the sustainable use of natural resources, there is a need to address more intensively the numerous interactions among production, consumption, trade and environment at different geographical levels. Because ofthe Man uses practically all terrestrial landscapes in a diverse way. Only around 5 per cent of temperate and tropical land area is absolutely uninhabited and subject to no direct anthropogenic influences. It is simply neither possible nor, in many cases, desirable, from an economic or – as will be seen – from an ecological point of view, to protect the biosphere completely from human influences (Miller et al, 1995). For example, in Germany only 35–40 per cent of native species live in protected areas (SRU, 1985). Marine and coastal ecosystems are also largely to be found in areas where fish are caught or other human activities making use of nature are carried out. Against this background it is clear that maintaining the functioning ofthe biosphere depends on the extent to which it is possible to use biosphere services sustainably and to minimize negative impacts on the biosphere (Miller et al, 1995; WRI et al, 1992). The deliberations in this section should be understood in the context ofthe development of a concept for the implementation ofthe ‘sustainable land use’ model. Section E 3.3 deals with a broad range of problems that occur in many forms of land use.What guides the findings for the implementation of sustainable land use is the differentiation between various types of landscape use outlined in Section E 3.3.1, which differ with respect to their varying extent of economic use interest and protection requirement. On the basis of this differentiation, a ‘system of differentiated intensities of use’ (Haber, 1971, 1998) should be developed for the various forms of land use – in each case adapted to the regional conditions – that specifies procedures for implementing forms of land use based on sustainability considerations. Opportunities for this will be addressed in the individual parts of this section. In the process, the discussion covers a continuum, ranging from areas to be strictly protected (Section E 3.3.2), through extensive land use (Section E 3.3.3) right up to intensively used arable land (Section E 3.3.4). Finally, within the context of regional management, there is a discussion as to how these various forms can be integrated (Section E 3.9).