Contenu du sommaire : Les territoires de la biodiversité

From biodiversity to diversities : the territorial dimension of biodiversity Biodiversity has become a subject of major interest since twenty years, giving rise to scientifc works, international conferences and discussions. Fears concerning the decline of life diversity take a strong place in the current environmental stakes. Without denying the reasons that justify such a concern, this paper focuse on the territorial aspects of the topic. The naturalist approach seems partly inadequate to deal with the matter in a spatial and temporal point of view. Taking in account “natural” and social areas enable to demonstrate the relativity of the matter and the diversity of cases. This paper consider biodiversity partly as a result of social history and thus, as a temporal process with period of decline alternating with period of expansion.

Biodiversity : a matter of perspective The prevailing view of biodiversity conveys the image of a « natural » capital, eroded and threatened by human activities, particularly in humid tropical regions. Behind this view lie a number of prejudices, postulates and prisms of various denominations that strongly undermine the currently catastrophism that is attached to it This dominant view has developed in the Western world within the of neo-malthusianism conceptual framework, a theory that has for long been proven wrong. Neo-malthusianism makes wide use of the obsolete theories of « natural equilibrium » and climax. It relies on a purely quantitative notion, while the real value of biodiversity is qualitative in nature. It totally ignores the fact that man has created almost all the biodiversity he uses every day. Finelly, it is based on a biodiversity « natural zero state » that nobody is able to define because it simply does not exist. Throughout history, all human societies have repeatedly rebuilt and manipulated biodiversity and ecosystems according to their needs. These difficulties strongly diminish the pertinence of the conservationist policies still forming the basis of international action, in contradiction with the objectives of poverty reduction in the poorest countries. In order to improve these policies, a new paradigm must be found.

From natural reservations to the biodiversity territories. The case of France Since the implementation of the National Park policy in France, several successive biodiversity conservation strategies have been implemented. The first one aims at isolating some portions of territory as National Parks or natural reserves ; it was followed by the creation of Regional Natural Parks, where biodiversity was weakly taken into account as a part of a natural or a cultural heritage of the inhabitants of a territory. Implemented by local authorities, Local management broader projects of local development took biodiversity issues into account. Agro-environment schemes and the Natura 2000 European network then change the way biodiversity was dealt with. In short, biodiversity replaced “nature” or “natural heritage”. The new Habitats and Bird directives take explicitly into account the relationships between land use practices and biodiversity : human action is no longer seen exclusively as having a negative impact. Human land use is likely to have a positive effect on the conservation of habitats and of patrimonial species or of communal interest, stakeholders' strategies and choices cannot ignore biodiversity anymore. As biodiversity becomes one of the criteria in land management, the value of geographical analysis is highlighted.

Biodiversity and sustainable development : the farmers of coastal Guinea Biodiversity is not a matter cut off from the social sphere. Reflection on biodiversity should be based on a dynamic representation of ecosystems, of technical systems and of resource utilisation strategies, it should be clear that there are no borders between « natural » milieus and development spaces. In Guinea coastland, concomitant roles played by the main mesological factors and modes of management favour a rich and diversified flora, from several biogeographical domains : the Sudanese-Guinean savannah flora maintained by early fires, the Guinean flora of the fallow lands, the semi-deciduous wet forest flora in gallery forest and wooded islets. These type of flora have for centuries all been more or less worked by man. This mosaic plays a fundamental part in the resilience of ecosystems. It guarantees the conservation of species. Current ecosystems are in equilibrium with the modes of management. Sustainability is at the heart of peasants' strategies. They are too strongly dependent on « natural » resources not to worry about their deterioration or non-renewal. They use a whole array of technical or social means to ensure this renewal. It seems pertinent today to consider local populations as the prime guardians of the conservation means, managers of biodiversity and beneficiaries of its development.

Biodiversity : confusing numbers, confusing territories Biodiversity has become one of the major issues of the 21st century. It is based on the notion of species whose definition is not universally acknowledged. Taxonomy, i.e. the inventory of living creatures, which relies on classification, is not yet completed. The figures concerning listed biodiversity are more and more reliable, where as the data concerning potential biodiversity belongs to the domain of approximation, extrapolation and exaggeration. The local issues of biodiversity have long been underestimated. The tropical area is viewed as the most diverse and the most at risk. Conversely, towns have until recently been perceived as non-natural objects, which contain hardly any biodiversity. These models are currently under review.

Biodiversity and Farmers'. Innovations in the Third World One of the main effects of the traditional « green revolution » was to drastically simplify the agro-ecosystems and to reduce exaggeratedly bio-diversity within cultivated areas. To the contrary, Third World farming communities have managed to develop and to perfect cropping and animal raising systems in line with the durable co-habitation of a wide range of both domestic and spontaneous varieties, species and races. Such is the case for Haitian and Burundian farm crop exploitations, for Southeast Asia agro-forestry systems and for Sudano-Sahelian (Africa) crops grown under tree cover. Those production systems, implemented by farmers whose best interest is not always to maximize the mathematical expectancy of work productivity, often make the most of carbon, nitrogen and mineral element cycles, while limiting the consumption of chemical fertilizers, fuels and phytosanitary products. As for caloric and proteinaceous yield per hectare, they have also proven to be of relative high efficiency

The forest patches biodiversity, “island anthroposystems” in openfield landscapes : the Western Gâtinais (France) case. To the south of Paris, between the Fontainebleau and Orléans forests, an extensive plateau forms the Western Gâtinais. The openfield landscape is made of many forest patches. A sample of 71 woodlots was studied in order to characterize their flora and to test the predictions of Island Biogeography and Landscape Ecology as regards to the richness of their species assemblages. We found 671 species overall. From one patch to the next, the species numbers vary greatly (minimum : 18 ; maximum : 270). The composition of assemblages is diversified, as 57 % of the species are present in less than 6 woodlots. The classical species-area relationships is not falsified, despite of some contrary examples. On the other hand, results are unclear as regards the isolation effect. Our results suggest that two landscape characteristics have a positive influence on the species richness : 1 - when forest patches form “archipelagos”, the species flows are probably facilitated, resulting in a higher species number in each patch (the “archipelago effect”) ; 2 - the species richness of a patch is related to the level of ecological heterogeneity of the surrounding landscape matrix. The comparison of old woodlots (existing before 1880) and “neo-patches” (created since 1880) does not reveal any correlation between species number and age : neo-patches can be as rich as old patches ; this observation suggests rapid dissemination processes. Human causes are to be taken into account to explain the differences of species richness between patches. We have established a global index of human influence : in large woodlots (5 ha and more), the species richness is significantly correlated to this index. The diversity of practices depends on the size of the woodlots ; the areas, shapes and relative locations of woodlots result from the evolution of land use : woodlots are “anthroposystems”. The trajectory of each one and the present state of its biodiversity is the result of a particular web of interactions between spontaneous and human-driven processes.

« Beyond Protected Marine Areas. Conservation networks and corridors along West-African Coast » Because of increasing pressure on seascape and ineffectiveness of coastal management, new conservation mechanisms are recommended to assure biological and cultural integrity. Protected system, based on continuous, bounded and closed areas, is unable to take into account complexity, diversity and mobility that characterise marine biodiversity. Beyond protected areas, new territories are built to integrate conservation objectives into sea use and regional and intersectoral planning at all levels. First, this article underlines the changes in coastal policies, from resource exploitation to heritage conservation. Second, it analyses management instruments and institutional frameworks built along West-African coast, from the first Ramsar sites (Arguin Banc in Mauritania, Djoudj in Senegal, etc.) to Biospher Reserves (Saloum Delta in Senegal) and specific regional planning (regional plan for marine turtles, etc.). Thirdly, the notion of biological corridor and its application are debated ; other territories of biodiversity conservation are examined, such as sacred sites. By the way, the geographic concepts of « terroir » and territory are re-investigated. Coastal areas management and marine policy finally lead to raise important questions of sea resource appropriation, their wise use and the role played by local communities.

Mediterranean plant biodiversity and human impact : macro and micro-regional approaches The human role appears to be central in the future of the Mediterranean environment, because its impact and management choices are responsible for the persistence of this high biodiversity. With 10 regional hotspots and 50 plant biodiversity refuge areas, the Mediterranean region is threatened by the quickness and the severity of the current and forecasted environmental changes. At a finer scale, the Maritime Alps regional hotspot constitutes the most important endemic center of the whole Alps region, but it has been subjected to drastic environmental transformations for the last decades. The comparisons between the distribution of refuges and human threats exhibit similar spatial patterns, both at the Mediterranean region scale and, to a lesser extend, at the Maritime Alps hotspot. Refuge areas constitute some of the most threatened territories due to a higher than average demographic pressure. Thus, facing the increasing threats on the Mediterranean biodiversity, it's essential to quickly undertake an integrative conservation framework at the Mediterranean scale which a prioritization toward refuge areas.