UNIDADES DE CONSERVAÇÃO:
Atualidades e Tendências 2004.
Fundação O Boticário de Proteção à Natureza, 2004.
Atualidades e Tendências 2004.
Fundação O Boticário de Proteção à Natureza, 2004.
Gustavo A. B. da Fonseca
Summary
Introduction
Thirteenthousend years ago, the western hemisphere underwent a major extinction spasm that completely change the chacterer of its fauna in period of less then 3.000 years. Magnificient mammals, including ground sloths, giant elk, mastodonts and saber-toothed tigers disappeared in the blink of an eye in geological time. While the exact cause of this transformation is still debated, there is increasing evidence that it was induced directly and indirectly by the progressive occupation of the american continente by humans (Alroy 2001; Flannery 2001; Dayton 2001).
Today, some of the earth's last remaining biodiversity "hotspots" appear headed for a similar cataclysm due to wiedspread loss of native habitat, particularly in the species rich topics (Myers et al. 2000). Even where forests still remain, in many areas inadequate protection has resulted in the elimination of most medium and large-bodies wildlife species, resulting in the so-called "empty forest syndrome" (Redford 1992).
This phenomenon is in effect the second phase of the human-induced bio-simplification of natural ecosystems initiate during the pleistocene.
Fourtunately, scientists studing these changes have now accumaleted enough information to provide strong prediction of can be expected if we do not intervene. Recent analyses suggest in the next five years, for example, Mesoamerica (Mexico to Panama) is likely to lose 10% of its remaining natural vegetation, whith whith the resulting extinction of at least 22 species of vertebrates and 93 species of plants (brooks et al. 2002). Even the wilderness Areas (Myers et al. 2000; Mittermeier et al. 2002) that, unlike the hotspots, still retain 70% or more of their native vegetation cover, are rapidly changing whith the advancement of agriculture frontiers. Anticipated loss of habitat in these areas will result in a far greater number of species ate risk of extinction (Pimm and Raven 2000).
Awareness of this impending crisis gives us early warning that if we do not act, it will soon be too late; the question is what actions are necessary. Despite increased conservation efforts, many critical areas are still lost each year.
Where to work: Biological Priorities.
The word is far too big and resources too limited for conservationists to be active everywhere. Setting priorities for investment and action is therefore vital.
If we minimise loss of biodiversity, as measured at the level of species, identifying areas concentrations of endemic (restricted range) plants and animals becomes paramount. Anumber of regions stand out globally as centers of terrestrial spaecies richness and endemism. Apioneering to indentofying these regions is represented by the Global Biodversity Hotspots, areas featuring expetional consentrations of endemic spaecies, and experiencing exceptionally rapid loss of habitat. Myers (1988,1990) was the first to highlight the extreme value oh these few terrestrial habitats that account for a significant potion of earth's biodversity represented by endemic species.
Re-analyses of this frame work (mittermyer et al. 1988,1999; Myers et al. 2000) define 25 hotspots, currently covering only 1.4% of the land surface of the earth, wish provide the only remaining habitat for an estimated 44% of all species of vascular plants and 35% of mammals, birds, reptiles and amphibians. All of hotspots have alredy lost more than 70% of their original vegetation. Since 1800, close to 80% of all bird species that have gone extict were lost from the biodversity hotspots (myers et al. 2000).
Site conservation Tools
Species conservation objectives are made more manageble by defining geographical focus areas. But once we decide where to work, the challenged becomes how to do effective conservation there. I will review evidence on the effectiveness of two main categories of conservation tools - protected areas and sustainable development projects, and draw conclusions for wat strategies are likely to be most effective in the future. Present new conservation tools, like the conservation concessions. Conservation corridors as to combine site conservation tools into an integrated strategy at a scale sufficient to address ecological and economic needs.
Beginning whith the model of Yellowstone National Park in the United States, the creation of protected areas to restrict directe use of biological resoucers became the predominant strategy to ensure the persistence of representative samples os native habitat and their associated biodiversity in many parts of the world. In the las two decades, however, protection through reservers, or activies tradicionally associated whith parks, such as border demarcation and enforcement, have been criticiezed as both inappropriate and ineffective (Soulé and Sanjayan 1998; Schwartzman et al. 2000).
A large portion of conservation effort is now dedicated to promoting, frequently as a directly substitute to parks, the rather vague concept to "sustainable development" (IUCN et al. 1991). Instead of seeking to separed areas for conservation from areas for resource use, sustainable development attempts to integrate them in the same place by promoting types and intensities of use that are profitable but compatible with conservation goals. This strategy try to promote, conservation, sustainable development can therefore ideally create situation in wich pressure on natural resources decreases, constituencies for conservation increase, and effective conservation becomes possible in a range of difficult contexts.
In contrast, ample evidence suggests that the protected areas have had a significant impact even whish relatively low levels of investment. In large areas areas across Latin America that are completly cleared, parks often stand out harbor the last remaining habitat (Dourojeanni 1999).
A study of 22 tropical coutries (Bruner et al. 2001) attempetd to quantify affectiveness in parks under high levels of threat. They used a sample of 93 parks to ases effectiveness by both calculating land clearing over time and comparing the conditions of parks whith the condition of their surrondings. They found that 83% of the parks in sampleexperienced no net clearing since they are stablished (median age 21 years), and that full 40% permitted the regeneration of native vegetation on land that was cleared at the time of park establishement. Only 17% had a net loss of they native vegetation to land clearing. In comparing parks whith they surroundings, although they found instances of serius degradation, most often from hunting, overall the parks, were in significantly better condition than their surrounding areas for all impacts tested (land clearing, logging, hunting, grazing, and fire).
Finally, challenging some common claims, the rate of creation of new protected areas has not slowed in recent years (WCPA 1999), demonstrating that oportunities still exist, and may even expainding to create and suport more protected areas in key ecossystems around the world. A wealth of data from countries like Brasil (Ayres et al. 1997) and India (Kutti and Kothari 2001) indicate burst of creation of additional parks and reserves during the last decade.
Indeed, reviews of Integrated Conservation and Development Programs (ICPDs) have found that sustainable development as a standalone conservation strategy has been widely unsuccessful (Wells et al. 1999, Terborgh 1999, CIFOR et al. 1999).
These limitations suggest that substituting protected areas for sustainable use schemes is, in itself, unlikely to result the fulfillment of conservation objectives, which means that support for protected areas continues as a top priority. Among projects can provide connectivity across fragmented landscapes, as well as local benefits and increased support for conservation.
The international community has long demonstrated a willigness to pay for conservation - currently at least half a billion dollars are spend on tropical biodversity conservation. Conservation concession have the potencial to address a number of the limitations of sustainable use, and providing concessions payments directly promote conservation meeting clearely defined and mesurable biodiversity conservation objectives. Through these mechanisms, conservation concessions can bring a clear market value to the protection of important areas, including enforcement activities, themseilves, research, ecotourism, watershed values, carbon, sequestration and training and education oportunities.
The limits of site Based Action: Bring Conservation to Landscape Scale
Where does this leave us? If parks can work for species conservation and there are serious limitations to sustainable development as a substitute, then it appears that conservation must come primarily from setting resources aside from human use, while enabling supporting role for sustainable use projects. Even where parks exist, many are too small to maintain ecological processes an alow for global change dynamics. In particular, changes driven by human - induced global warming may cause such serius shifts in habitat locations that protected areas that do not contain an altitudinal gradient may lose all sustable habitat for the species they are designed to protecte (Peters and lovejoy 1992, Hannah et al. 2002).Finally millions of peoples living in poverty, highly indebted governaments, massive growing levels of consumption in developed countries, and whith world population expected to increase by another 3 bllion in the next 50 years (UN 1998).
To face these challenges, we must find a way to implement conservation strategies that address development needs, but still put conservation tools in place at a scale commensurate whith ecological processes. We call conservation planning units at this scale landscape-level biodiversity corridors, a concept first articulated in the connection ehith a major project designed to simulated the creation of addittional protected areas in Brazilian Amazon and Atlantic Forest, financied by the Brazilian governament and World Bank's Pilot Project to Conserve the Brazilian Rain Forest (Ayres et al. 1997).
