Conservation outcomes are the full set of quantitative and justifiable conservation targets in a hotspot that should be achieved to prevent biodiversity loss. These targets are defined at three hierarchical levels: species (extinctions avoided); sites (areas protected); and landscapes (corridors created), corresponding to recognizeable units of biodiversity along an ecological continuum. As conservation in the field succeeds in achieving the targets, they become demonstrable results or outcomes. Thus, outcomes are the biological underpinning of CEPF’s investment strategy in the eastern Himalayas, enabling CEPF to target its limited resources to species, sites and landscapes of global conservation concern. Given that these outcomes are quantifiable targets, CEPF will be able to monitor the success of its investments.
The three levels of targets for achieving conservation outcomes interlock geographically through the presence of species in sites and of sites within landscapes. They are also linked ecologically; if species are to be conserved the sites in which they live must be protected, and the landscapes provide for ecological linkages between sites, so that ecological processes and dynamics associated with the species, and the natural communities of which they are a part, are maintained.
This process of defining conservation outcomes requires knowledge on the global conservation status of individual species and accurate data on the distribution of threatened species across sites and landscapes in the region. Because of its focus on the global biodiversity hotspots, it is crucial that the process used to derive conservation targets for CEPF is based on a global standard. Thus, the principal basis for defining species outcomes is the global threat assessments contained within
The 2002 IUCN Red List of Threatened Species (IUCN 2002), which is based on quantitative, globally applicable criteria under which the probability of extinction is estimated for each species. The species outcomes for the eastern Himalayas consist of those species that are globally threatened (i.e. Critically Endangered, Endangered and Vulnerable). Avoiding extinctions means conserving globally threatened species to make sure that their Red List status improves or at least stabilizes.
One of the shortcomings of this selection process is that global threat assessments and reliable population trend data are incomplete or unavailable for most species, especially the taxonomic groups that comprise the small, yet abundant species. However, the majority of the species outcomes are still represented by the larger vertebrates. Since these species are more easily monitored, and because many act as umbrella species for overall biodiversity, use of the prominent, larger vertebrates as conservation outcomes, especially as measures of conservation successes, is justifiable.
Given that many species are best conserved through the protection of a network of sites at which they occur, sites holding populations of globally threatened species were identified. These sites are considered "key biodiversity areas" or site outcomes. Thus, the site outcomes represent discrete land areas that harbor populations of at least one globally threatened species and should be protected from ecological transformation to conserve the target species that live within them. Sites are scale-independent, and the defining characteristic is that it is an area that can be managed as a single unit. Otherwise, a site can be any category of protected area, governmental land or privately owned property. The main objective of defining important sites for conservation of threatened species is to identify areas where investments can be made to prevent species extinctions and biodiversity loss.
In the Eastern Himalayas Region, the starting point for defining key biodiversity areas, or site-scale conservation outcomes, was the suite of protected areas and Important Bird Areas (IBAs). IBAs are by definition key biodiversity areas because they have been identified for bird species of global conservation concern. A second data source of information on sites was obtained from the World Conservation Monitoring Centre protected areas database. BirdLife International and its affiliates, the Bombay Natural History Society, and Bird Conservation Nepal, identified the IBAs (Baral and Inskipp 2001, M. Crosby in litt. 2003, Z. ul-Islam in litt. 2003). Each globally threatened species in the other taxonomic groups was evaluated as to the sites in which it occurs, which included both the IBAs (many of which are protected areas) but also required identification of additional sites. Much of this work was done during the expert consultations.
Corridor outcomes focus on the need for conservation at a landscape-scale to capture ecological and evolutionary processes that maintain biodiversity, especially over the long term. Corridors preserve ecological and evolutionary processes, and species that cannot be conserved at the site scale alone, by maintaining connectivity between important sites. Corridor outcomes are particularly important to conserve the large vertebrate species that occur at naturally low densities, have large home ranges or territories, or exhibit dispersal or migratory behavior as part of their natural history that make their effective and long-term conservation unlikely in sites alone. These species were considered to be "landscape species" (sensu Sanderson et al. 2001). Corridor outcomes were also selected on the need to maintain ecological processes, such as the need to maintain habitat connectivity to allow for seasonal altitudinal migrations and hydrology that are not directly associated with species outcomes.
In the Eastern Himalayas Region, several large vertebrate species qualify for landscape species status. Notable among these are the tiger, snow leopard, Asian elephant, clouded leopard and some of the larger birds, such as the vultures, adjutants and hornbills. The ecological processes critical to the Eastern Himalayas Region that have to be captured by corridor outcomes include the altitudinal seasonal migrations by several birds and mammals (and presumably by fishes), and maintenance of hydrological processes along the steep Himalayas watersheds.
Anchored on key biodiversity areas, corridor outcomes were defined on the basis of existing linkages of natural habitat across environmental gradients and between site outcomes. These habitat linkages provide for area and movement requirements of wide-ranging species that cannot be conserved at the site scale alone. The definition was assisted by consultations with and opinions of local experts in each country, complemented by analysis of spatial data on land-cover, elevation and human population distribution. The results of ecoregion-based conservation assessments conducted in the region by WWF (Wikramanayake et al. 1998a, Dorjee 2000, Myint et al. 2000) were also included in the analysis of corridor outcomes.
BirdLife International compiled the list of species outcomes for the Eastern Himalayas Region by extracting the globally threatened species that occur in the region from the
2002 Red List of Threatened Species (IUCN 2002). For amphibians, the results of the Global Amphibian Assessment (IUCN-SSC and CI-CABS 2003), which has completed threat assessments and prepared distribution maps for most Old World amphibian species, were used, since this assessment will update the IUCN Red List for amphibians in 2004. Information on threats, distribution and needed conservation actions for each of the globally threatened species was augmented and revised with information from other databases, consultations with experts and with input from Aaranyak; ATREE; Bird Conservation, Nepal; CEE; and WWF.
The species outcomes for the eastern Himalayas consists of 163 species, comprising 45 mammals, 50 birds, 17 reptiles, 12 amphibians, 3 invertebrates, and 36 plant species (Appendix 1). Since there are no globally threatened fish species listed from the Eastern Himalayas Region, outcomes for this taxon were not defined. We note that comprehensive global threat assessments of invertebrates, fish and, to a lesser extent, plants, are needed and should be considered a high priority to compile a complete list of species outcomes.
Fourteen of the species outcomes are Critically Endangered, 46 are Endangered and 102 are Vulnerable (Table 1). One species, the black softshell turtle (
Aspideretes nigricans) is considered to be extinct in the wild by IUCN (2002), but a population was recently rediscovered in Assam Valley, northeastern India (Praschag and Gamel 2002), and should occur in several sites, including Kaziranga National Park, D'Ering Wildlife Sanctuary, Pakke Wildlife Sanctuary, Namdapha National Park, Dibru Saikhowa National Park, Manas Tiger Reserve, Orang National Park, Nameri National Park and Majuli (F. Ahmed, Aaranyak, pers. comm.).
Of the 163 species outcomes: 146 (90 percent) occur in northeastern India, including 70 species that are endemic to the Eastern Himalayas Region; 75 (46 percent) occur in Nepal; and 49 (29 percent) occur in Bhutan.
Among the important globally threatened mammals are Asia’s three largest herbivores, namely the Asian elephant, greater one-horned rhinoceros and the wild water buffalo; largest carnivore, the tiger; and several large birds such as vultures, adjutant storks, and hornbills. All these species have extensive habitat requirements and cannot be conserved within small, protected areas without compromising their ecology, behavior, and demographics. A full list of all globally threatened species is provided in Appendix 1.
Site Outcomes
To define key biodiversity areas, or site outcomes, BirdLife International finalized the list of globally threatened species for the region. A list of sites, which included all protected areas and IBAs in Bhutan, Nepal, and the northeastern Indian states, was also generated. A matrix was generated documenting the occurrence of globally threatened species per site. The matrices were presented at the expert roundtables and participants were asked to provide information on: a) verification of the species recorded for that site, b) the importance of that site for conservation of globally threatened species; c) the level of threat to the site; d) any ongoing and planned conservation investments at that site; and e) the potential role for civil society in conservation at that site.
A total of 175 key biodiversity areas were identified for the Eastern Himalayas Region (Table 2, Figure 2a,b and c). Of these, 101 sites (58 percent) harbor populations of globally threatened mammal species, 164 (94 percent) have globally threatened, restricted-range or congregatory bird species, 45 (26 percent) have globally threatened reptile species, and 17 (10 percent) support populations of threatened amphibian species (Appendix 2).
Detailed data on the distribution of globally threatened plant species in sites are unavailable, and a comprehensive global threat assessment reflecting true global conservation priorities within most plant groups is lacking. Eight sites (Singalila, Neora Valley, Mahananda, Senchal, Maenum, Kyongnosla Alpine Sanctuary, Barsey Rhododendron Sanctuary, Pangolokha Wildlife Sanctuary) and one conservation corridor (Kangchenjunga-Singalila, including the connection to Mahananda) were identified as being important for plants during the Gangtok roundtable based on IUCN Red-Listed plants. Another 52 sites across the region were assessed as being important for conservation of nationally threatened plant species, especially those endemic to the Eastern Himalayas Region. The full list of site outcomes in the Eastern Himalayas Region is presented in Appendix 2.
Site outcomes could not be identified for several species. These are listed as follows:
- Rusty-throated wren babbler (Spelaeomis badeigularis) — No confirmed records of this species from anywhere since the type series were collected in 1947 from Dreyi in the Mishmi Hills, but it is probably widespread in the eastern Himalayas and northern Myanmar (BirdLife International 2001).
- The crowned river turtle (Hardella thurjii) was identified from Kosi Tappu Wildlife Sanctuary in Nepal during the expert roundtable, but its range distribution includes the Indus and Ganges-Brahmaputra river systems in Pakistan, northern India, Nepal and Bangladesh; thus it should also be found in the Terai Arc, North Bank and Kaziranga-Karbi Anlong landscapes.
- No sites were identified for the Narayanghat whipping frog (Polypedates zed).
- The Himalayas dragonfly (Epiophlebia laidlawi) inhabits wetlands along the foothills, especially in Nepal, and can likely be captured within the Terai-Arc Landscape.
- The range of Ludlow’s Bhutan swallowtail (Bhutanitis ludlowi) overlaps with the sites within the Bhutan Biological Conservation Complex.
- Since the pygmy hog is the sole host for the pygmy hog sucking louse (Haematopinus oliveri), it is reasonable to assume that conservation of the Critically Endangered host will help to conserve the Critically Endangered louse.
The Indian eyed turtle (
Morenia petersi) was only assigned to Gainda Tal in Nepal, but its known distribution is also widespread, across the Ganges river basin in eastern India and Bangladesh (
http://emys.geo.orst.edu/collection/species/Moreniapetersi/Moreniapetersi.html), and should be included within the Terai Arc, North Bank and Kaziranga-Karbi Anlong landscapes.
Of the 175 site outcomes in the Eastern Himalayas Region, only 84 (48 percent) are completely or partly included within nationally gazetted protected areas.
Many site outcomes support numerous globally threatened species. In particular, Koshi Tappu, Bardia, Chitwan and Sukla Phanta in Nepal and Dibru-Saikhowa, Kaziranga, Nameri and Buxa in northeastern India support at least 20 globally threatened vertebrate species each.
Some site outcomes are considered irreplaceable because they support globally threatened species that only occur in those sites, or are one of few sites that are known to contain globally important populations of globally threatened species. These include Namdapha National Park in Arunachal Pradesh, which is the only site in the world known to support Namdapha flying squirrel and one of only two sites known to support the snowy-throated babbler (
Stachyris oglei). Orang Wildlife Sanctuary in Assam is the only site known to have the Orang sticky frog (
Kalophrynus orangensis). Rongrengiri Wildlife Sanctuary and Siju Caves in Meghalaya are the only sites in the region known to harbor the Kashmir Cave bat (
Myotis longipes). The irreplaceability of various sites informed the prioritization of outcomes for CEPF investment.
Because survey effort in the region is uneven—there are large areas that are still biologically unexplored—the available data on the distribution of globally threatened species in the Eastern Himalayas Region vary substantially across the region and among taxonomic groups in terms of comprehensiveness. Consequently, site outcomes identified as being important for conservation based on one taxonomic group, or even a species, may also be important for other groups for which data are not yet available. On the other hand, there could also be other sites that harbor globally threatened species, or even unidentified species that should qualify for globally threatened status but have been missed in this analysis.
To achieve corridor outcomes, habitat linkages connecting sites within a landscape need to be maintained or restored to support species and processes that require larger spatial scales than sites can provide. Landscapes also capture more biodiversity than the sites because of the “beta-diversity effect,” especially since landscapes include more ecosystem, habitat and land-management variability. The corridor outcomes were defined based on the ecological requirements of landscape species they support, as well as key ecological processes such as migrations, dispersal and other ecological linkages such as hydrology. In the Eastern Himalayas Region, the landscape species include the following:
- The Asian elephant, which requires extensive home ranges and spatial areas that include their seasonal migrations.
- The tiger, Asia’s largest carnivore, maintains large territories. Subadults disperse from natal areas to establish territories elsewhere. Thus, effective conservation of tigers will require maintaining conservation landscapes where dispersal corridors link core areas that harbor breeding populations.
- The snow leopard is a high altitude predator that has large home ranges and occurs at low densities.
- The clouded leopard, which is an elusive predator that occurs at low densities in lowland forests.
- Takin is a montane ungulate that ranges over wide areas, and undertakes seasonal migrations.
- The large bird species such as the vultures, adjutants, and hornbills, which require large spatial areas with specific habitats and habitat structures for roosting and nesting. These large birds range over wide areas and can be considered landscape species since their movements can transcend single sites.
- The greater one-horned rhinoceros can be managed within sites with intensive habitat management that will increase the carrying capacity of the site. This is being done now in Kaziranga, Chitwan, Bardia and Suklaphanta. But, such management compromises the natural ecology of the site and survival of other specialist species, such as the grassland birds, hispid hare and pygmy hog. Thus, a more effective way to conserve the rhinoceros is to treat it as a landscape species, where it is conserved at lower, more natural densities, over larger spatial areas. Such management will qualify the rhinoceros as a landscape species because of the larger spatial requirements to conserve a population at lower densities.
Thirteen landscapes were defined where corridor outcomes need to be achieved in the Eastern Himalayas Region (Table 3; Figure 3), covering 132,482 square kilometers, equivalent to more than 32 percent of the total area of the region. These landscapes range in size from 492 square kilometers (Neora Valley-Toorsa corridor) to in excess of 19,000 square kilometers (Dibang-Dihang Landscape).
Overall, the landscapes include 97 (76 percent) of the faunal species outcomes and 89 (51 percent) of the site outcomes. The faunal outcomes included in the landscapes comprise of 36 (80 percent) mammals, 42 (84 percent) birds, 16 (94 percent) reptiles, 3 (25 percent) amphibians, and all three invertebrates. The number of sites contained in the landscapes range from 2 to 17 (Table 3).
The Eastern Himalayas Region contains 17 Tiger Conservation Units (TCUs), landscapes that have been identified to conserve metapopulations of tigers. Four of these are Level 1 TCUs or high priority tiger conservation landscapes (Wikramanayake et al. 1998b). All four of these Level 1 TCUs overlap with the landscapes; thus the tiger conservation priorities in the region are captured within the landscapes identified during this exercise, especially within the Terai Arc Landscape, Bhutan Biological Conservation Complex and the North Bank Landscape.
Several corridor outcomes were also identified to ensure that important ecological and evolutionary processes in the region are maintained. In this region, altitudinal migration, especially by birds, is an important process that depends on altitudinal continuums of natural habitat. Hydrologic processes are also significant ecological targets.
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