Ecology of Indonesian Papua Part Two. Andrew J. Marshall
Читать онлайн книгу.
restrict their analyses to examining the effects of biodiversity loss within one trophic level. At larger temporal and spatial scales and in changing environments the number of species required to maintain ecosystem services increases (Hooper et al. 2005; Loreau et al. 2001, 2002). Research has now largely shifted away from focusing on simple indices of species richness to attempting to identify key functional species or groups that have disproportionate effects on ecosystem services (Loreau et al. 2001; Naeem and Wright 2003; Rosenfeld 2002).
There is debate over the extent to which biodiversity-ecosystem function studies have direct relevance for conservation biology (Hector et al. 2001; Lawler et al. 2001; Schwartz et al. 2000; Srivastava and Vellend 2005). The lack of universal support for a direct link between biodiversity and ecosystem function has led some to suggest that widespread use of this linkage as a justification for conservation goals is unwise (Krebs 2001; Lawler et al. 2001; Schwartz et al. 2000). Others acknowledge this point but argue that interactions between biodiversity and ecosystem services can provide useful additional arguments in support of conservation (Hector et al. 2001). It has also been suggested that although research on the relationship between biodiversity and ecosystem function has had limited conservation applications to date, this area promises to provide important insights into conservation policy in the foreseeable future (Lawler et al. 2001; Srivastava and Vellend 2005). While there is much debate in academic circles on how reduction in species richness or loss of key functional groups will effect the function and stability of ecosystems (and the pertinence of these debates to more applied conservation issues), the vast majority of ecologists agree that these losses will increase susceptibility to invasion by exotic species (and presumably also pathogens), reduce environmental services, and negatively impact the biosphere (Hooper et al. 2005; Loreau et al. 2001; Schla¨pfer et al. 1999). Therefore, as ecologists work to identify which species and functional groups are irreplaceable, a precautionary approach to biodiversity preservation should serve as a broad governing theme in conservation management in Papua.
THE PAPUAN PROTECTED AREAS NETWORK
The Papuan protected areas network encompasses approximately 66,500 km2 of terrestrial habitats. The major ecosystems are not equally or proportionately represented within Papua’s protected area system (Table 5.1.3). The most well protected land cover classes are lower montane forests and subalpine forests, with over 45% of each ecosystem type found within formally protected areas. However, lowland evergreen forest, by far the most dominant ecosystem type in Papua (61% of land area), is proportionately the least well represented in protected areas, with only 14.5% of this ecosystem type occurring within currently designated parks and reserves. This is a source of major concern as lowland forest is the ecosystem type most likely to suffer heavy degradation from uncontrolled human development, logging, and mining. In other parts of Indonesia almost all lowland forest found outside protected areas has disappeared or been severely degraded (Fuller et al. 2004; Holmes 2002; Jepson et al. 2001; van Schaik et al. 2001; World Bank 2001), with substantial losses even occurring within protected areas (Curran et al. 2004). Although this trajectory of habitat loss is far from inevitable in Papua, we would be well advised to consider the worst-case scenario that few forests in Papua will exist in their present state outside protected areas at the end of the 21st century. Under this scenario the current protected areas network in Papua is unlikely to be sufficient to protect the full complement of species, ecological processes, and ecosystem functions that is found there today. Assessment of this possibility will require careful consideration of the representation of ecosystem types within the current Papuan protected areas network, the prospects for maintaining connectivity between ecosystems, and the potential effects of global and regional climate change on the spatial distribution of ecosystems.
Unforested lands are excluded. GIS analysis of protected areas map overlaying Landsat 7 ETM imagery of Papua, using a combination of images acquired in 1999 and 2000.
Source: Forest Watch Indonesia–Conservation International–Ministry of Forestry.
ECOSYSTEM-BASED CONSERVATION APPROACHES
Numerous strategies are currently employed and championed by scientists, conservation organizations, and government agencies involved in natural resource management. The widely-publicized ‘‘Biodiversity Hotspots’’ approach advocates prioritizing severely threatened areas of high species richness and endemism (Myers et al. 2000). Other strategies suggest that preservation of large wilderness areas that are ecologically intact and sparsely populated represent important opportunities for biodiversity conservation (Mittermeier et al. 2003). Some have argued that conservation efforts should focus almost exclusively on landscapes that are largely unaltered by humans (e.g., Myers 1980; Noss 1991), while others embrace the conservation potential of the careful management of lands that have already been substantially impacted (e.g., by development or logging, Fimbel 1994; Fimbel et al. 2001; Frumhoff 1995; Johns 1983; Marshall et al. 2006; Meijaard et al. 2005). Integrated conservation and development projects promise simultaneously to protect biodiversity and promote human well-being, health, and poverty alleviation (Goodwin and Swingland 1996; McShane and Wells 2004; Salafsky et al. 2001), while others suggest that the most effective way to conserve wildlife and habitats is strict protection and exclusion of most local people from protected areas (e.g., Terborgh 1999). Numerous campaigns have focused on the conservation of single species or specific taxonomic groups (e.g., Mittermeier et al. 2005; Stattersfield et al. 1998) and others work to preserve ecosystems, ecoregions, or functional landscapes (Hudson 1991; Noss 1996; Pressey et al. 1993; Woinarski et al. 1996). Each approach has strengths and limitations (Bonn and Gaston 2005; Kareiva and Marvier 2003; Kiss 2004; Young 1999; Orme et al. 2005; Possingham and Wilson 2005), and it is likely that the most favorable conservation outcomes will result from careful application of a broad portfolio of conservation tactics and strategies.
Although a range of conservation strategies have applicability to Papua, the fact that Papua’s ecosystems provide services of local, regional, and global importance strongly suggests that ecosystem-level conservation approaches are particularly warranted. The specific goals of ecosystem-based conservation plans will need to be carefully considered within the Papuan context, but the five basic goals of ecosystem management proposed by Grumbine (1992, 1994) provide a useful point of departure. Ecosystem management should strive first to protect sufficient habitat to ensure the long-term viability of populations of all native species; second, to represent all native ecosystem types across their range of natural variation within protected areas; third, to manage ecosystems on spatial scales that are sufficiently large to maintain important ecological processes (e.g., disturbance regimes, hydrological processes, nutrient cycles); fourth, to create ecosystem management plans for sufficiently long time scales (e.g., centuries) to permit evolutionary change; and fifth, to allow for human use and occupancy at levels that do not result in ecological degradation (Grumbine 1992, 1994). Ecosystem-based conservation plans in Papua are likely to be complicated to devise and even more challenging to implement effectively. Political support will need to be generated at all levels of government, ecosystems will need to be legally defined and delineated, consensus among diverse ethnic groups will need to be reached, and effective mechanisms to monitor the success of conservation interventions will need to be implemented. Ultimately, conservation efforts in Papua will not be successful unless such large-scale conservation issues are tackled.
Papua, and New Guinea more broadly, is a region of global biological significance. It includes the highest summit in Oceania, the only equatorial glaciers in the Pacific, the most extensive and diverse mangrove forests in Indonesia, and one of the world’s largest remaining tracts of lowland tropical forest. Human population density in Papua is low. Rates of forest loss and remaining forest cover in Papua are encouraging when compared with many other areas in the tropics. Papua also is home to extensive and highly-diverse reefs that remain largely undamaged, at least in comparison to those in western Indonesia and many other parts of the world. However, threats to these ecosystems exist and will likely increase over time. We should have no illusions that protection of Papua’s ecosystems will be easy or simple. Despite unprecedented investment in conservation, efforts to protect Indonesia’s other lowland forests have largely failed (Curran et al. 2004; Fuller et al. 2004; van Schaik et al. 2001; Whitten et al. 2001). Our current conservation strategies