Ecosystem Profile: Western Ghats & Sri Lanka

Conservation Outcomes
Biological diversity cannot be saved by ad hoc actions (Pressey 1994). In order to support the delivery of coordinated conservation action, a core part of the profiling process includes defining "conservation outcomes." By presenting quantitative and justifiable targets against which the success of investments can be measured, conservation outcomes allow the limited resources available for conservation to be targeted more effectively and their impacts to be monitored at the global scale. Therefore, conservation outcomes form the basis for identifying biological priorities for CEPF investment in the Western Ghats.

Biodiversity is not measured in any single unit but, rather, is distributed across a hierarchical continuum of ecological scales (Wilson 1992). This continuum can be condensed into three levels: species, sites, and landscapes. These three levels interlock geographically, through the occurrence of species at sites and of species and sites in landscapes, but are nonetheless identifiable. Quantifiable targets for conservation can be set in terms of "Extinctions Avoided" (species outcomes), "Areas Protected" (site outcomes), and "Corridors Consolidated" (corridor outcomes).

Defining targets for achieving conservation outcomes is data driven and employs a set of quantitative criteria. Therefore, the process is dependent upon the availability of data on globally significant biodiversity. In the Western Ghats, because data on global threat status are only available for mammals, birds, amphibians, plants, and to a lesser degree, reptiles and fish, conservation outcomes were only defined for these groups. Defining conservation outcomes is a fluid process and, as data become available, species-level outcomes will be expanded to include other taxonomic groups that previously had not been assessed, as well as restricted-range species.

Conservation outcomes are defined sequentially, with species outcomes defined first, then site outcomes and, finally, corridor outcomes. It is a bottom-up process both ecologically and institutionally. The work to define conservation outcomes, as described in this document, uses standards and procedures set by CABS as well as additional methods and tools developed at ATREE and WCS, data synthesis and analysis on outcomes was also conducted at UAS. Information gathered was presented to and refined by experts at the Western Ghats CEPF Stakeholder Workshop.

Species Outcomes
The principle underlying the definition of species outcomes is to avoid extinctions at the global level. Because of its mandate to conserve biodiversity globally, it is crucial that the process used to derive conservation targets for CEPF should be based on a global standard. The basis for defining species outcomes were the global threat assessments contained within The 2002 IUCN Red List of Threatened Species (IUCN 2002), which represented the best available data source on the global conservation status of species at the time the outcome definition process took place. The Western Ghats species listed as Critically Endangered, Endangered, and Vulnerable in the IUCN Red List were considered as conservation targets. This definition excluded Data Deficient species, which were considered to be priorities for further research not conservation action per se, as well as species threatened locally but of lower conservation concern globally, which were considered to be national or regional conservation priorities but not global priorities. Species outcomes are achieved when a species' global threat status improves or, ideally, when it is removed from the Red List.

Data were compiled for each target species on its conservation status, threats, and known distribution. In the case of amphibians, the results of the Global Amphibian Assessment (IUCN-SSC and CI-CABS 2003), which completed threat assessments and prepared distribution maps for most Old World amphibian species were used in addition to the IUCN Red List.

Adequate information on the Western Ghats freshwater fish and invertebrates has not been compiled into the IUCN Red List. Reptiles, fish, invertebrates, and vascular plants other than trees have not been comprehensively assessed and consequently, the number of globally threatened species on the IUCN Red List is considered to be a gross underestimate. There are several endemics in all taxa from the Western Ghats that are not represented in the IUCN Red List and it is a major priority to work toward getting these groups assessed.

The initial results of the species outcome definition indicate that 332 globally threatened species occur in the Western Ghats (Table 1). The globally threatened flora and fauna in the Western Ghats are represented by 229 plant species, 31 mammal species, 15 bird species, 52 amphibian species, four reptile species, and one fish species. Of the total of 332 globally threatened species in the Western Ghats, 55 are Critically Endangered, 148 are Endangered, and 129 are Vulnerable. The full list of species outcomes is given in Appendix 1.

Table 1. Summary of Species Outcomes for the Western Ghats

Taxonomic Group Critically Endangered Endangered Vulnerable Total
Mammals 3 7 21 31
Birds 2 1 12 15
Repriles 0 1 3 4
Amphibians 11 28 13 52
Fish* - - 1 1
Plants 39 111 79 229
Total 55 148 129 332

The sole freshwater fish listed as a species outcome—the blind catfish (Horaglanis krishnai)—is found in wells of the Kottayam district of Kerala. Twenty-two of the globally threatened amphibian species in this hotspot have highly restricted distributions. They are known only from one or two sites. Other species with a very restricted distribution in the Western Ghats are the Wroughton’s free tailed bat (Otomops wroughtonii) known only within the Western Ghats from Barpede cave in Khanapur taluk in Karnataka and the Kondana field rat (Millardia kondana) known only from its type locality Sinhgarh in Marahrashtra. A total of 18 species outcomes are shared between the Western Ghats and Sri Lanka. These consist of eight mammals, three birds, one reptile, and six plants.

In addition to identifying the globally threatened species that occur in the Western Ghats, participants at the CEPF Western Ghats stakeholder workshop identified species or groups of animal species that, while not assessed as globally threatened, were considered to be of global conservation concern. They were, therefore, included on a list of provisional species outcomes, which may become eligible for CEPF investment if their conservation status is reassessed as globally threatened during the investment period (Appendix 2).

Site Outcomes
Given that many species are best conserved through the protection of a network of sites at which they occur, a set of targets for achieving site outcomes, or "key biodiversity areas," were defined according to a number of criteria. Key biodiversity areas are defined using a set of quantitative, globally consistent criteria: the regular occurrence of significant numbers of one or more globally threatened species, restricted-range species, or globally significant congregations. Sites are delineated as physically and/or socioeconomically discrete areas that could potentially be managed for conservation. Sites can be protected areas, other governmental lands such as reserved forests, community lands, or private farms or plantations. Site outcomes are met when a key biodiversity area is protected, through improved management or expansion of an existing conservation area, or creation of a new conservation area.

In the Western Ghats information on the sites in which globally threatened and restricted range species occurred was gathered from published literature as well as consultation with experts and field experience of the team. The globally threatened species criteria for defining key biodiversity areas was applied to all taxa; the criteria on restricted-range species and congregations was applied only comprehensively for birds using the Important Bird Area (IBA) data, as compiled by BirdLife International and its Indian partner- the Indian Bird Conservation Network (IBCN) of the Bombay Natural History Society (BNHS). The administrative boundaries of protected area categories such as National Parks and Wildlife Sanctuaries as well as Reserved Forests and Forest Divisions were used to delineate polygons in a GIS within which presence of species could be located based on the above sources of information.

A total of 126 key biodiversity areas were identified for the Western Ghats (Table 2, Figures 5 and 6). These sites occur throughout the Western Ghats across all the major vegetation types. Most of the site outcomes were identified based on mammal and bird information. Forty-seven sites were identified for amphibians and 24 sites were identified for reptile species. Sites could not be identified for the one freshwater fish species occurring in the Western Ghats due to lack of information. Sites were identified for 64 percent of the globally threatened plant species. Site outcomes were not identified for the remaining 36 percent of globally threatened plant species because the data were not available at the appropriate scale during the time in which this analysis was conducted. The integration of these data is a priority for the future.

Ten of the site outcomes, or key biodiversity areas, are considered to be wholly irreplaceable on a global scale, because they contain the only known populations of a globally threatened animal species (Table 3). Since the sites are irreplaceable for Critically Endangered and Endangered species, they qualify as Alliance for Zero Extinction (AZE) sites, which are the most urgent site-level conservation priorities on a global scale. Sixty-three of the 126 sites (50 percent) have been provisionally designated as IBAs (as per information provided by the IBCN). Fifty-four of the sites (approximately 43 percent) are within the protected area network. The remaining 72 sites consist of a range of landscape and administrative units of varying scales, from reserve forests to forest divisions to private lands and even a single cave. The full list of site outcomes, including information on their protected status, is presented in Appendix 3.

Table 2. Summary of Site Outcomes for the Western Ghats

No. of sites identified for species outcomes per taxonomic group
Mammals 100
Birds 68
Reptiles 24
Amphibians 47
Fish- -
Plants + 53
Total Site Outcomes 126

† Key biodiversity areas, or site outcomes, were not identified for 36 percent of globally threatened plant species because the data were not available at the appropriate scale during the time in which this analysis was conducted.

Table 3. Wholly Irreplaceable Sites in the Western Ghats

Site Name Species for which the site is wholly irreplaceable Class IUCN Status
1. Bhadra TR Micrixalus kottigeharensis Amphibia CR
2. Forests of Gundia-KN Minervarya sahyadris Amphibia EN
3. Indira Gandhi WLS & NP / Annamalai / Top Slip Indirana phrynoderma; Rhacophorus pseudomalabaricus Amphibia CR
4. Kalakkad- Mundunthurai TR Nyctibatrachus vasanthi Amphibia EN
5. Mukurthi NP Philautus tinniens Amphibia CR
6. Sinhagad –MH Millardia kondana Mammalia EN
7. Amboli Philautus “Amboli forest” Amphibia CR
8. Kemphole RF Indirana gundia Amphibia CR
9. Munnar area Philautus griet; Philautus chalazodes Amphibia CR

Site outcomes could not be identified for the small mammals Hemiechinus nudiventris, Prionailurus viverrinus, Rattus ranjiniae, Hipposideros hypophyllus, and the fish species, Horaglanis krishnai, because information on their localities could not be obtained during the time this profile was being developed. Two species of mammals, Loris tardigradus and Melursus ursinus, occur in nearly all of the sites.

Figure 5: Full Set of Site Outcomes for the Southern Western Ghats (PDF, 450 KB)

Figure 6. Full Set of Site Outcomes for the Northern Western Ghats (PDF, 477 KB)

Corridor Outcomes
Targets for achieving corridor-level conservation outcomes are focused on landscapes that need to be conserved in order to allow the persistence of biodiversity over time. Species and site outcomes are nested within corridors. The goal of corridors is to preserve ecological and evolutionary processes, as well as enhance connectivity between important conservation sites by effectively increasing the amount of habitat with biodiversity value near them. Unlike species and site outcomes, the criteria for determining corridor outcomes are not well defined as this is presently a subject of ongoing research.

The wide-ranging or “landscape” species identified in the Western Ghats are the Asian elephant, the tiger, the Asiatic wild dog, the greater spotted eagle, the white-backed vulture, and the long-billed vulture. The conservation of these species cannot depend upon a site-based approach alone and requires the protection of larger landscapes. Thus, for the purposes of this profile, some of the considerations that were taken into account when identifying corridors were: areas that provide connectivity for movement of wide-ranging species such as elephants and areas that provide buffers of suitable habitat types to existing protected areas. Results of landscape level analyses done for this profile as well as previous assessments and prioritization studies conducted in the Western Ghats were taken into account while defining corridor outcomes.

The definition of corridors in the Western Ghats was done at two levels. Larger landscape units were defined as corridors on the basis of available information on wide-ranging species’ movements, distribution of site outcomes, and connectivity of suitable habitats. The wide-ranging species for which there was a good range of information were tiger and elephant (Wickramanayake et al. 1999, Venkatraman et al. 2002). The connectivity of suitable habitats was assessed by using a vegetation map. Within these larger landscapes, critical links or patches of relatively unfragmented natural habitat that provide crucial connectivity between sites or buffer existing sites, especially protected areas, were then defined at a finer scale (Figures 7 and 8). The definition of these critical links was based on the distribution of intact forest habitat and presence of unique and threatened ecosystems. The latter range from wet evergreen forest communities with Myristica swamps or Ochlandra reeds in the southernmost subregion, dry scrub, and open deciduous forests in the Mysore plateau-Kaveri subregion to high elevation grasslands and associated shola ecosystems in the central Western Ghats and moist deciduous forests in the northern regions.

In effect, critical links represent priority areas that are essential to the consolidation of corridors. None of the critical links defined currently fall within the protected area network.

Five landscape-scale corridor outcomes were defined for the Western Ghats by analyzing the distribution of the site outcomes, existing and potential forest connectivity, ranges of landscape species, and topography (Table 4, Figures 7 and 8). Moving from south to north, these corridors are Periyar-Agasthyamalai, Anamalai, Mysore-Nilgiri, Malnad-Kodagu, Sahyadri-Konkan. Nineteen site outcomes do not occur within any of the corridors and would need to be targeted additionally.

Figure 7. Corridor Outcomes and Critical Links in the Southern Western Ghats (PDF, 76 KB)

Figure 8. Corridor Outcomes and Critical Links in the Northern Western Ghats (PDF, 61 KB)

Table 4. Summary of Corridor Outcomes

Corridor Outcomes Region Area (km2) No. of Site Outcomes Represented* No. of Species Outcomes Represented
Periyar-Agasthyamalai Western Ghats 7,734km2 11 158
Annamalai Western Ghats 6,014 km2 14 90
Mysore-Nilgiri Western Ghats 19,153 km2 31 102
Malnad-Kodagu Western Ghats 21,345 km2 36 59
Sahyadri-Konkan Western Ghats 10,489 km2 15 26

* Nineteen sites fall outside corridors in Western Ghats.

Periyar-Agasthyamalai Corridor
This corridor covers an area of 7,734 square kilometers (4.3 percent of the total Western Ghats area) in two states, Tamil Nadu and Kerala. It contains 11 site outcomes (9 percent) and 51 of the faunal species outcomes (50 percent). This is the highest number of species outcomes captured among the corridors. Among the site outcomes represented in this corridor, six are protected areas covering a total area of approximately 2,010 square kilometers (15 percent of the Western Ghats protected area network) or about 30 percent of the corridor. Approximately 30 percent of the area of this corridor is covered by areas containing globally threatened species that are outside the protected area network such as Ranni Forest Division and Kulathapuzha Forest range in Kerala. The site Tirunelveli FD, which is outside the existing protected area network, is among the richest areas in globally threatened and endemic plant species in the Western Ghats (Ganeshaiah 2003), in addition to being provisionally designated an IBA. Some of the other non-protected areas in this corridor are also very significant from a conservation perspective as they contain unique ecosystems such as the Myristica swamps found in Kulathapuzha and Palode Forest Ranges in Kerala.

There are large areas within this corridor under plantations, some of which, cardamom in particular, provide habitat outside protected areas for globally threatened and endemic species. The forest types in this corridor are predominantly wet evergreen with high levels of endemism across all taxa. There are significant areas of dry evergreen and dry deciduous forests on the eastern side of this corridor. This corridor ranks the highest in terms of Western Ghats endemic tree species of evergreen and semi-evergreen forest types. It also contains very important areas for the conservation of endemic herpetofauna in the Western Ghats. In addition, it has one of the most important populations of the lion tailed macaque.

Anamalai Corridor
This corridor covers an area of 6,014 square kilometers (3.3 percent of the total Western Ghats area) in two states Kerala and Tamil Nadu. It contains 14 of the site outcomes (11 percent) and 40 (or 39 percent) of the species outcomes for animal taxa. Among the site outcomes represented, 10 are protected areas covering a total of 1,717 square kilometers (12.5 percent of the Western Ghats protected area network), which is about 29 percent of the corridor. Approximately 40 percent of this corridor is comprised of non-protected areas of conservation significance, such as the Palni Hills. The latter is an important area for the conservation of the Endangered and endemic Nilgiri tahr (Hemitragus hylocrius). This region as a whole contains sites that hold the largest viable populations of tahr remaining in the Western Ghats, mostly within the existing protected area network. The corridor is also important for the conservation of landscape species such as elephants, tigers, and wild dogs. The Anamalai corridor contains some of the best and largest areas of shola grasslands in the Western Ghats. Other major vegetation types found within this corridor are wet evergreen, moist deciduous forest to the west and southwest, and dry deciduous forest on the northeastern side. Of the five Western Ghats corridors, this area ranks third in the number of tree species endemic to evergreen and semi-evergreen forests in the Western Ghats (Ramesh et al. 1997). It also contains one of the richest non-protected areas for the conservation of endemic plants in the Western Ghats – Mankulam Forest Range in Kerala (B.R. Ramesh pers. comm.). There are large areas under tea plantations in the central and southern parts of this corridor, in the Valparai plateau and the Munnar area respectively. Reservoirs are a major source of fragmentation in this landscape corridor.

Mysore-Nilgiri Corridor
This corridor covers an area of 19,153 square kilometers (10.6 percent of the total Western Ghats area), making it the second largest of the five Western Ghats corridors. It is the widest corridor covering three states: Karnataka, Kerala, and Tamil Nadu. Thirty-one (25 percent) of the site outcomes for the Western Ghats are contained within this corridor. Of all five corridors, this one covers the largest number of animal species outcomes (57 in total or about 55 percent). Among the site outcomes represented in this corridor, 12 are protected areas covering a total of 3,806 square kilometers (or 27.6 percent of the Western Ghats protected area network). The protected areas cover 18.6 percent of the corridor. Approximately 28 percent of this corridor is occupied by unprotected areas with globally threatened species. This corridor also contains some of the best habitats and populations for the conservation of landscape species such as elephant, tiger, and wild dog in the Western Ghats. The largest population of Asian elephants is found within this corridor (Sukumar 1989).The areas falling in the Nilgiri Biosphere Reserve area are especially significant for the conservation of these species. There are a great variety of habitat types in this corridor. They range from some of the best examples and largest contiguous stretches of dry deciduous and scrub forests in the Western Ghats towards the east, to wet evergreen forests towards the western side. There are also some important hotspots of endemism in this corridor such as the Silent Valley National Park. This protected area and its surrounding forests are among the most important sites for the conservation of the lion-tailed macaque. This landscape is second only to the Agasthyamalai region in its richness of semi-evergreen and evergreen tree species (Ramesh et al 1997). Large portions of this corridor are occupied by tea and coffee plantations in the mid to upper elevations besides exotic tree plantations in the Nilgiris. There is one critical link between this corridor and the Malnad-Kodagu corridor that is crucial for movement of landscape species such as elephants and tigers.

Malnad-Kodagu Corridor
This corridor covers an area of about 21,345 square kilometers (11.9 percent of the total Western Ghats area), making it the largest corridor in the Western Ghats. Unlike the other corridors, this one is contained within a single state: Karnataka. Thirty-six (29 percent) of the site outcomes for the Western Ghats are contained within this corridor. The number of animal species outcomes covered in this corridor is 36 or about 35 percent of the total. Among the site outcomes represented in this corridor, there are seven protected areas covering a total area of 2,463.52 square kilometers (about 18 percent of the Western Ghats protected area network). This accounts for 11.5 percent of the total corridor area. The non-protected areas containing globally threatened and endemic animal species account for about 5 percent of the corridor. These areas lie primarily along the main ridge of the Western Ghats and provide relatively good connectivity between existing protected areas, particularly for tropical wet evergreen forest species such as the lion-tailed macaque. The protected areas in this corridor are important for the conservation of tigers and wild dogs in the Western Ghats. There are also some hotspots of herpetofaunal diversity within this corridor. The area between Pushpagiri WLS, Kudremukh NP, and Bhadra TR is particularly rich in endemic and globally threatened amphibian species. The stretch of forest between Brahmagiri WLS and Agumbe RF ranks fourth in terms of richness of tree species endemic to evergreen and semi-evergreen forests in the Western Ghats. The areas east of Bhadra Tiger reserve such as parts of the Bababudan hills and Yemmadoddi are potentially important for maintaining a meta-population of tigers in this landscape. The main vegetation types in this corridor include tropical wet evergreen forests, moist deciduous forests, dry deciduous forests, grasslands, and scrub. There is high degree of fragmentation in this corridor along an east-west axis. Coffee plantation is a major land use type in the southern region of this corridor and exotic tree-species plantations have been established over large areas. This corridor also has the unique depauperate and simplified “Soppina-Betta” lands which are former moist forests areas which were selectively logged and later managed for leaf manure production by local farmers

Sahyadri-Konkan Corridor
This corridor covers an area of about 10,489 square kilometers (5.8 percent of the total Western Ghats area) across 3 states: Karnataka and Maharashtra and one Union Territory – Goa. It contains 15 or about 12 percent of the site outcomes and 21 or 18 percent of the species outcomes for animal taxa. Among the site outcomes represented in this corridor, 11 are protected areas covering a total area of 2,862 square kilometers (about 21 percent of the Western Ghats protected area network). This accounts for 27 percent of the total corridor area. Dandeli has a large population of hornbills and Anshi and other evergreen forests further south could be potential sites for the reintroduction of the lion tailed macaque since it is locally extinct. There is a potential for supporting a metapopulation of tigers in the central and northern part of this corridor from Anshi to Radhanagari WLS. There are very few sites in this corridor outside the protected area network which contain globally threatened animal species. One of the non-protected sites in this corridor is irreplaceable for certain globally threatened and highly endemic species: Amboli – for Bufo koynayensis, Ramanella mormorata, and Philautus “Amboli forest.” The major vegetation types in this corridor are moist deciduous and evergreen. The evergreen forests of this area are relatively poor in tree endemicity compared to the evergreen forests of the southern Western Ghats. The forests within this corridor are more fragmented than those of the other four corridors. In the northern part of this corridor, reservoirs are a major landscape feature.

Contents / Previous / Next

Western Ghats & Sri Lanka

Ecosystem profile
Investment priorities
News & Feature Archive