Herbert Sukopp

Biodiversity in Berlin and its potential for nature conservation

Selected habitats in Berlin (Germany) were investigated with a focus on the diversity of flora and land use patterns. On the one hand, the correlation between the number of plant species and the diversity of land use patterns is shown for a transection running from the center to the outskirts of Berlin. The greatest variety of land use patterns and the highest number of species per square kilometer can be found in the transition zone between the city center and the outskirts where urban structures are closely associated with open spaces like large parks, urban forests, and larger wastelands. In accordance with the intermediate disturbance hypothesis, the mosaic of land use patterns in the transition zone with moderate frequencies or intensities of disturbance positively affects habitat diversity, as well as overall species diversity on the landscape level. Furthermore, in residential areas built in the 1920s and 1930s, the flora was studied from both a historical and a present-day perspective in order to assess the diversity of wild-growing indigenous and non-native plant species, wild-growing ornamental plant species, and planted trees. The highest numbers of species were recorded in less intensively managed habitats. In addition to structural factors (e.g. land use patterns) determining the diversity of flora and vegetation in cities, this study also demonstrates the importance of the historical factor for biodiversity. The differences in land use throughout the last 70 years (pre- and post-World War II era) can be seen as an explanation for the relatively high diversity of the flora in the investigated residential areas. n nCities have to be regarded as a new type of environment with species compositions and habitats peculiar to urban-industrial areas. Future research and planning of nature conservation and sustainable development of urban-industrial areas should take the biological diversity in cities fully into account. Recommendations are given for the maintenance and development of biological diversity in cities, focussing on landscape and habitat as well as species diversity.

ON THE EARLY HISTORY OF URBAN ECOLOGY IN EUROPE

Early investigations on the ecology of cities were in the tradition of natural history and focused on single biotopes. Of special interest were the plants and animals introduced into new areas directly or indirectly by man. In Central Europe, studies of anthropogenic plant migrations and cultural history were combined in a specific way, the so called Thellungian paradigm. The succession of vegetation on ruins after the bombing during the Second World War was studied in many cities. Ecological studies on whole cities started in the 1970s with investigations on energy flow and nutrient cycling. Today the term urban ecology is used in two different ways: in developing programs for sustainable cities, and in investigation of living organisms in relation to their environment in towns and cities.

Urban Ecology — Scientific and Practical Aspects

We are living in a century of rapid urbanisation. The United Nations forecasts that by the year 2025, 60% of the world’s population will be living in urban areas, compared to 29% in 1950. The 50% mark will be reached between the years 2000 and 2010. In 2025, more than a dozen cities will have over 20 million inhabitants, and some will have over 30 million. 23 of the 25 biggest urban conglomerations on the planet will be in Africa, Asia and Latin America, rather than in Europe or North America.

Biotope mapping and nature conservation strategies in urban areas of the Federal Republic of Germany

Two methods of biotope mapping and species recording in urban areas are presented. n1. n(1) Selective biotope mapping in which only certain biotopes deemed worthy of protection are mapped. The examples presented here are the biotope mapping of Munich and the rapid biotope mapping of Dusseldorf. n n2. n(2) Comprehensive mapping, in which all biotopes found in the city are surveyed. Comprehensive mapping according to the method used in Berlin is described as an example. n nThe evaluation of areas solely on the basis of selective mapping is considered to be inadequate because biotopes, especially in urban areas must be evaluated in the context of their surroundings. On the other hand, comprehensive mapping involves higher costs and more time and personnel. n nThe recommendations of the “Working Group on Biotope Mapping in Settled Areas” are summarized. n n3. n(1) Comprehensive mapping should be given preference over selective mapping. n n4. n(2) The size of study sites in comprehensive mapping should be approximately 4 ha. n n5. n(3) A map scale of 1:5000 (in Berlin 1:4000) is suitable for field surveys. n n6. n(4) A clear distinction between built-up areas and the urban fringe must be made when data are being recorded. n n7. n(5) The recording of floristic, phytosociological and — whenever feasible — faunistic data must be on the basis of defined land-use types. n n8. n(6) Lists of flora should either be complete or include a defined selection. n nThe present position of biotope mapping in the cities of the Federal Republic of Germany is given. n nFinally, the Species Conservation Program for the city of Berlin is cited, as an example where the results of surveys have actually been interpreted in terms of nature conservation strategies. In this respect, the following guidelines for urban development are of great importance: n n9. n(1) further use of land for building purposes must be minimized; n n10. n(2) consideration should be given to natural development in the inner-city area; n n11. n(3) the variety of typical urban landscape elements should be conserved; n n12. n(4) habitat differences should be preserved; n n13. n(5) a network of open spaces should be maintained; n n14. n(6) there should be functional integration of building in the ecosystems. n n n n nThe Species Conservation Program contains measures for the care and development of all urban biotope types. The measures for the biotope type “closed block building substance” are presented as an example.

Human-caused impact on preserved vegetation

Abstract Climate, soil, air, and water in cities respond sensitively to human impacts that are usually much stronger than in rural areas. In spite of the multitude of impacts cities are quite rich in habitats as well as in plant and animal species. Typically, disturbance of urban ecosystems leads to a decrease in the number of species native to the region and an increase of introduced non-native species. This process is at least partly reversed in the course of succession. Disturbance and the recovery from it during succession are key factors determining the habitat mosaic in urban ecosystems. As an ever increasing percentage of the world’s population lives in cities, the conservation of urban biota is of great importance. In many parts of the world urban ecosystems and their impact regimes as a prerequisite of conservation are not sufficiently studied.

Changes of the reed beds along the Berlin Havel, 1962–1987

Abstract The decline of reed populations along the shores of the River Havel in Berlin is traced on the basis of regular population surveys. The causes for the observed reduction are described, as well as the effects on the biocommunities and the environment at the waters edge. Finally, the protective measures carried out are assessed.

Changing climate and the effects on vegetation in central European cities.

Summary Since the 1850s the effects of global climatic warming have been anticipated by the rise of temperature in many big cities. In addition, changes of vegetation in central European cities have been well documented. This paper explores, first of all, the changing urban distribution of some ruderal herbaceous species, and secondly distributional and physiological aspects of tree and shrub species in response to this rise in temperature. Examples of species reactions which are given here include Acer negando, Ailanthus altissima, Amelanchier, spicata, Berberis julianae, Buddleja davidii, Colutea arborescens, Cornus alba, C. stolonifera, Cotoneaster bullatus, Cytisus multiflorus, C. striatus, Juglans regia, Laburnum anagyroides, Ligustrum vulgare, Mahonia aquifolium, Paulownia tomentosa, Philadelphus coronarias, Platanus × hispanica, Populus × canadensis, Prunus armeniaca, P. laurocerasus, Z3. mahaleb, P. persica, P. serotina, Pyrus communis, Quercus cerris, Q. rubra, Q._robur, Ribes aureum, Robinia pseudacacia, Sambucus spp., Sorbus intermedia agg., Symphoricarpos albus and Syringa vulgaris. The responses of some woody scramblers and creepers are also examined. Thereafter, phenological investigations are briefly reviewed. These include studies on both Aesculus hippocastanum and Tilia euchlora. Finally, the conclusion considers the extent to which cities can, in effect, act as simulators of global climatic change. It is concluded that, for example, urban areas also differ in other, possibly causal, ecological and socio-economic factors affecting the vegetation. However, many of the alien or exotic invader species found colonising cities (or naturalising within them) derive from warmer areas and are considered to benefit from a more favourable climate, even on a small spatial scale.

The City as a Subject for Ecological Research

The city, in today’s meaning for Central Europe, may be considered in the context of the development of modern technology and new energy sources. However, historically, cities may be considered in a narrower context, associated with the erratic increase in the world population. During the 1960s, the percentage of the population living in urban areas (i.e., areas with more than 20,000 inhabitants) was estimated to be 30% world wide (with the highest rates in North America 46%, Northwest Europe 54%, and Australia and New Zealand 65%). Thus, it is understandable that the most recent ecology has been focussed on the most densely populated regions (Aschenbrenner et al., 1970, 1972, 1974a,b: Dansereau 1970; Muller 1972, Fitter 1946, Kieran 1959, Miyawaki et al., 1971, Peters 1954, Rublowsky 1967). The often repeated statement that each city is generally hostile to life, seems to be disproved in several ways. It was surprising to find that the first investigations of urban locations, showed that, with existing complications, purely anthropogenic biotopes can offer suitable habitats with characteristic species combinations. The species combinations of such habitats vary between industrial facilities, railways, ports, rubbish dumps, and so on, and may be different from those known from other habitats. The flora of economically important species have been carefully researched in only three German cities: in Stuttgart (e.g. Kreh 1951), Leipzig (e.g. Gutte 1971), and in Berlin. The fauna has been researched in Hamburg, Kiel, Dortmund and Berlin (Erz 1964, Mulsow 1968, Weidner 1952, Wendland 1971). Ecology is now stronger and more systematic than in previous years; human influences in the conurbations have been studied, and research programs have been developed. In recent years, ecological research projects have been initiated in Berlin (Kunick 1973, Runge 1973, Sukopp 1966, Zacharias 1972), and the preliminary results will be reported here.

Influence of different landscape design styles on plant invasions in Central Europe

When considering the most frequent invasive exotic plants on an international scale, it is evident that the majority are ornamentals and that they were deliberately introduced in relation to landscape design. Although there are worldwide numerous lists of invasive exotic plants—which means plants that have harmful effects on native biodiversity—an assessment of the contribution of different landscape design styles on plant invasions has not been done. We used the extensive database on the history of introduction and naturalization of alien plants into natural habitats of Central Europe (Lohmeyer and Sukopp, Agriophyten in der Vegetation Mitteleuropas in: Schriftenreihe Vegetationskunde 25, 1992; Nachtrag: Braunschweiger Geobotan Arbeiten 8:179–220, 2001) to examine how many alien ornamental plants there are in the different natural habitats; and how many of them are invasive exotic plants and—in contrast—how many have not spread significantly. Also, we researched contributions by different landscape design styles to these plant invasions since medieval times. Of the estimated 12,000 alien plant species introduced into Central Europe since the Neolithic period, 279 taxa (2.3xa0%) are currently identified as being naturalized in natural habitats; 103 (0.86xa0%) of these naturalized taxa are ornamentals, and of these, 40 (0.33xa0%) are invasive exotic plants. Our investigation has shown a correlation between the frequency of plant invasions and changes in landscape-design styles. Evaluating the impact of plant invasions through horticulture and landscape design on native biodiversity, our study illustrates that it is significantly lower in Central Europe than in other parts of the world.

Lessons Learnt, Open Research Questions and Recommendations

This chapter represents the summary of the common analysis within the Interdisciplinary Research Group Society – Water – Technology. Lessons learnt, research gaps and recommendations are presented as the outcome of the analysis of the two case studies Fergana Valley and Lower Jordan Basin and as a conclusion from the cross-analysis based on the evaluation framework and the considerations outlined in Chap. 3 (Bismuth et al., Research in two cases studies: (1) Irrigation and land use in the Fergana Valley and (2) Water management in the Lower Jordan Valley. In: Huettl RF, Bens O, Bismuth C, Hoechstetter S (eds) Society water technology: a critical appraisal of major water engineering projects. Springer, Dordrecht, 2015, in this volume).