Noordwijk.M van, 'Segregate or integrate nature and agriculture for biodiversity conservation? Criteria for agroforests', pp.1-16, 1995 | Human use of biotic resources ('agriculture' in its widest sense) and biodiversity ('nature' in its widest sense) are both needed by society at large, but there are generally conflicts between these two aspects of 'land use'. conflicts between 'nature' and 'agriculture' can be solved by segregating nature and agricultural land (maximizing agricultural production on relatively small part of the land for nature as it is possible ) or by integrating nature into agricultural land through the adaption of production system that allow sufficient agricultural production while ensuring conservation of considerable parts of biodiversity of the natural system. Multi functional forests and agroforests are examples of the 'integrate' option, intensive agriculture plus nature reserves are an example of the segregate pathway.Mixed strategies are feasible where nature reserves coexist with pure agricultural production systems for some commodities and where production system integrate nature and agriculture for the commodities. All three options have strong advocates, and it is not clear which solution is optimum under which conditions.Objective criteria are needed for distinguishing which solution may best meet the multiple goals formulated under different circumstances.A simple model is used to derive a decision scheme. It distinguishes 'internal' biodiversity of land use system and 'external' biodiversity, by requiring only a part of the area for agriculture. If two production systems are compared, biodiversity conservation will be maximized if the system is chosen with the highest agricultural productivity per unit biodiversity loss. If agricultural intensification is treated as a continuous process, a similar criterion can be used to distinguish between situations where 'segregation' or 'integrate' forms the best solution. Further research is needed to check the assumptions behind the proposed equations, to quantify the scaling function of biodiversity in order to assess the effectiveness of both ' internal' and 'external' biodiversity conservation, and to determine the feasibility of implementation of opinions in the 'real world'

Increasing demands for products and services from tropical forests require solutions that conserve biodiversity while responding to human needs. I review various paradigms of tropical forest resiliency and fragility to focus attention on the management of biodiversity. The management of tropical biodiversity is possible within the context of land use programs that focus on ecosystem management. New ecological paradigms of tropical‐forest resiliency underpin tropical‐ecosystem management. They can and/or should replace paradigms that highlighted ecosystem fragility and led to the belief that tropical forests cannot be managed. To lead the way in tropical‐ecosystem management, ecologists must also consider social, political, and economic factors that affect the way people relate to the biota. Ecosystem management will require use of modern technology to mitigate the negative consequences of poor development and land use practices. In spite of efforts to preserve ecosystems as they occur today, species composition of future tropical forest landscapes will be different than today's.

More effective control of tsetse-transmitted trypanosomiasis may open vast areas of Africa to livestock production, both increasing food production and endangering biodiversity on the continent. This paper Reports on the Development of a conceptual model of the linkages between trypanosomiasis control and land-use, and then discusses approaches to determine how land-use change affects the environment. The conceptual model integrates epidemiological, ecological, economic and social information into the study of control-induced changes in land-use at continental, regional, national and local scales. Geographical information systems (GIS) are used to generate hypotheses and to analyse broad-scale patterns, while field studies are used to establish causality and to ground-truth large-scale data sets. Preliminary analyses provide support for the hypothesis that trypanosomiasis is retarding the large-scale correlations show that there is no simple inverse relationship between the presence of tsetse and the presence of agricultural land-use and that tsetse appears to limit agricultural land-use more strongly in southern than in West Africa. These results imply that decisions concerning where and when to control trypanosomiasis can have strong implications for the success of efforts to enhance human welfare and to maintain environmental quality.

The global project on 'Alternatives to Slash and Burn' agriculture was ,initiated by a consortium of international and national research institutes to speed up intensification of the use of convened forest land, in order to help protect the f;'remairling forest areas for their biodiversity values as well as role vis-a-visgreenhouse gas emissions. In the first phase of the project, benchmark areaswere chosen and fun her (:;haracterized in Brazil, Camerbon and Indonesia. Datafor the Indonesian t)enchmark areas on Sumatera are discussed here in the lightof the hypothesis that '1ntensifying land use as alterrlative to slash-and-burnfarming can help to reduce deforestation, conserve biodiversity, reduce netemission of greenhouse gasses and alleviate poverty', We conclude that thist1ypothesis indicates only one of three necessary conditions. Apart from farmeradaptabletechnologies, effective protection of the remaining forests is needed aswell as a reduction of other driving forces of deforestation | D Murdiyarso, 'Soil aspects of the lndonesian benchmark area of the global project on alternatives to slash and burn', pp.33-69, 1995

This book highlights biomass energy options in India which promote land reclamation, local employment, and self-reliance - as well as reducing greenhouse-gas emissions and dependence on oil imports. The authors analyse the sources, end uses, and socio-economic and environmental impacts of biomass energy; suggest measures for promoting sustainable yields, biodiversity, and community involvement in biomass production systems; describe some of the financial and policy barriers; and present strategies for the promotion of bioenergy. They show that land is not a constraint for growing woody biomass, even in a densely populated country such as India, and that appropriate institutional and financial policies can promote the large-scale application of bioenergy in developing countries committed to sustainable and equitable development. Biomass, energy, and environment demonstrates the potential of modernized biomass to meet the fuel and electricity requirements of India's rural population and indicates the potential for biomass in other developing countries, many of which are richer in bioresources than India. It will be of special interest to all those involved in deciding and implementing development, energy, land-use, and environmental policies.

Land managers need new tools, such as spatial models, to aid them in their decision‐making processes because managing for biodiversity, water quality, or natural disturbance is challenging, and landscapes are complex and dynamic. Spatially explicit population models are helpful to managers because these models consider both species‐habitat relationships and the arrangement of habitats in space and time. The visualizations that typically accompany spatially explicit models also permit managers to "see" the effects of alternative management strategies on populations of interest. However, the expense entailed in developing the data bases required for spatially explicit models may limit widespread implementation. In addition, many of the models are developed for one or a few species, and dealing with multiple species in a landscape remains a significant challenge. To be most useful to land managers, spatially explicit population models should be user friendly, easily portable, operate on spatial and temporal scales appropriate to management decisions, and use input and output variables that can be measured affordably.

Although far less published than loss of biodiversity on land, the loss of marine genetic, species and ecosystem diversity is a global crisis in its own right. The coastal strip (the shallow water, the intertidal area and the immediately adjacent land) is the most vulnerable as well as the most abused marine zone. Coastal ecosystems are not only an important source for essential products for mankind, including foods, medicine, raw materials and recreational facilities, but also provide ecological services that directly benefit the coastal zone. Loss of biodiversity in coastal ecosystems has both direct and indirect causes. The direct mechanisms involved include habitat loss and fragmentation, physical alteration, over-exploitation, pollution, introduction of alien species and global climate change. The root causes that drive these proximate threats lie in the high rate of human population growth, the unsustainable use of natural resources, economic policies that fail to value the environment and its resources, insufficient scientific knowledge, and weak legal and institutional systems. The ever-growing exploitation of the coast and its resources is a reflection of the steady population increase, especially in coastal zones. Habitats are changed or lost by accelerating urbanization, development of tourist facilities, industrial installations and mariculture. Land-based and upstream activities alter sedimentation and freshwater input in downstream estuaries and coastal biotopes. Contaminants from sewage disposal and agricultural runoff are rapidly increasing and areas of eutrophication and chemical pollution are expanding. Careless disposal of plastic wastes not only causes a litter problem but also widespread mortality of marine species. Exploitation of living marine resources may damage habitats and alter food webs, while mariculture generates its own pollution and may upset ecological balances by the introduction of alien species. Global atmospheric changes, which may result in altered rainfall patterns and rising sea-level, have become a matter of growing human activities have dramatically increased the intensity, pace and kind of environmental changes that lead to habitat loss and pose severe adaptive challenges to marine organisms. Response to these changes includes drastic declines of many fisheries and extinction of several species. The loss of species and ecosystems obscures the important threats to genetic diversity, which is essential for species survival in a changing environment. | Published

The coastal ecosystems of many African countries contain some of the most biologically diverse and productive habitats but they are also the most vulnerable as well as the most abused marine zone. Coastal ecosystems are net only an important source of essential products for consumptive, commercial and recreational use, but also provide ecological services that directly benefit the people. Due to the many living and commercial opportunities it offers, the coastal zone contains densely populated areas. Those areas especially are seriously threatened by human activities with consequent loss of their biodiversity. The direct mechanisms include habitat loss and fragmentation, physical alteration, over-exploitation, pollution, introduction of alien species and global climate change. Human impacts on coastal ecosystems are widespread. Habitats are changed or lost by the urbanization, development of tourist facilities and industrial installations, land reclamation and conversion, dredging and mining activities. Land-based and upstream activities alter sedimentation and freshwater input in downstream estuaries and coastal biotopes. Contamination from domestic and industrial sewage disposal and from agricultural runoff is also rapidly increasing and leading to eutrophication and chemical pollution. Disposal of solid wastes, especially plastics, not only causes a litter problem but also widespread mortality in marine species. Some types of exploitation of living marine resources may damage habitats and alter food webs, while maricuIture generates its own pollution and may upset ecological balances by the introduction of alien species. Human activities have dramatically increased the intensity, pace and types of environmental changes with an impact upon the coastal habitats and the resources they sustain. These changes may lead to the drastic decline of coastal fisheries and loss of biodiversity. The main root cause which drives these human activities lies in the high rate of human population growth, economic policies that fail to value the ecological service of the environment and its resources, insufficient scientific knowledge, and weakness in institutional and legal systems. | Published

This book provides information on the botanical characteristics, distribution (both original, and as an exotic in tropical Africa), phenology, propagation, silviculture, and utilization, for about 105 tree species found in the biogeographic transition zone of Guinea, West Africa - i.e., the zone between evergreen forest and the savanna zone. The book refers mainly to Guinea, although data is included which is pertinent to this zone in other countries (Guinea-Bissau, Cote d'Ivoire, Ghana, Togo, Benin, Nigeria and Cameroon). As well as the data for each individual species, there are introductory chapters which discuss (1) land use in the transition zone, (2) criteria used to select species, (3) describe and define silvicultural techniques employed, and (4) discuss biodiversity in the region. The data catalogue is arranged alphabetically by scientific name. There are many tables appended: common names of species in 17 African languages as well as French, German and English; silvicultural uses (agroforestry, rehabilitation, erosion control, soil improvement, etc.); wood properties and wood utilization of species; and glossaries of botanical and silvicultural terms used. The good quality colour illustrations focus on diagnostic features of the species, such as whole tree form, bark, foliage, flowers, fruits and seeds.