CURRENT STATUS OF FAUNAL DIVERSITY IN BELLANWILA – ATTIDIYA SANCTUARY , COLOMBO DISTRICT-SRI LANKA

The present survey shows the biodiversity decline in Bellanwila Attidiya Sanctuary (BAS). A total of 152 species of vertebrates and 75 species of butterflies are recorded from BAS. Sixteen of these species are endemic, and five of them are nationally threatened. Vertebrates represent 11 amphibians, 27 reptiles, 22 fresh water fishes, 78 birds and 14 mammal species. Habitat destruction, industrial toxic waste and garbage dumping are the major threats to the biota of the BAS. Key wards: Wetland, Biodiversity decline, Threats, Endangered species, Colombo, Conservation Introduction Sri Lanka is not isolated from the current global period of mass extinctions (Achard et al., 2002; Jenkins, 2003). Many species of animals, plants and other organisms are disappearing by the direct or indirect human activities in the planet: deforestation (Brook, et al., 2003; Ferraz et al., 2003; Pethiyagoda, 2005, 2007a), global warming (Alfred et al., 2007; Harvell et al., 2002; Rosa et al., 2007), invasive alien species (Elton, 1958). Pollution (MacNeely, 1992), fire (Batuwita & Bahir, 2005; Swinbanks, 1997), erosion (Hewawasam et al., 2003), agro chemical use (Hayes et al., 2002; Pethiyagoda, 1994), infectious diseases (Daszak et al., 2000; Pounds et al., 2006) and lack of systematic or scientific understanding (Pethiyagoda, 2007b; Bahir, 2009; Bahir & Gabadage, 2009a,b). Already in Sri Lanka, known extinctions include many plants and trees (Pethiyagoda, 2005), twentyone amphibian species (Stuart et al., 2004; Manamendra-Arachchi & Pethiyagoda 2005; TAPROBANICA, ISSN 1800-427X. April, 2010. Vol. 02, No. 01: pp. 48-63, pls. 2. © Taprobanica Nature Conservation Society, 146, Kendalanda, Homagama, Sri Lanka. CURRENT STATUS OF BELLANWILA–ATTIDIYA SANCTUARY 49 TAPROBANICA VOL. 02: NO. 01 Meegaskumbura et al., 2007) and two freshwater fish extinctions from Sri Lanka (Pethiyagoda, 1994; Pethiyagoda et al., 2008b). Because of the paucity of biological inventory in many regions of the country, other extinctions may have gone unnoticed. Indeed, since new species are still being described, it is possible that some species may go extinct before becoming known to science. It is alarming that human population density in our biologically richest wet zone is one of the highest on earth. Also, the population is growing more rapidly than average around protected areas (Wittemyer et al., 2008), a trend that seriously threatens the remaining biodiversity trapped in forest reserves and this is perhaps true for Sri Lanka. Although the Western Ghats and Sri Lanka is a biodiversity hotspot for conservation priorities (Myers et al., 2000; Mittermyer et al., 2004), unfortunately it is one of the most populous identified (Cincotta et al., 2000). Recent research highlighted the uniqueness of the Sri Lankan fauna from the mainland (Bossuyt at al., 2004; Bossuyt et al., 2005; Helgen & Groves, 2005). Therefore, we need to conserve and protect our natural wealth more aggressively than we have so far. Several Sri Lankan animal and plant taxa not only contain assemblages of endemics, but these sometimes constitute old branches or distinct clades of the tree of life (Bossuyt et al., 2004; Roelants et al., 2004). This is significant because radiations of tens of species are found exclusively on Sri Lanka (Bossuyt et al., 2005; Gunawardene et al., 2007; Helgen & Groves, 2005; Meegaskumbura et al., 2002). Therefore, conservation managers could treat these clades of animals and plants as the island’s major natural treasure (Bossuyt et al., 2005). Protecting these endemic taxa as “umbrella species” would result in protection of other rare and endangered species. It is in that perspective noteworthy that Sri Lanka’s diversity largely restricted to the formerly rain-forested southwestern wet zone, knuckles mountains and the central hills where only a little natural forest with many of the endemics now survive, beset by invasive alien species of plants and surrounded by plantations and settlements. The threats to the unique biodiversity recognized and the challenges to its conservation are therefore formidable and demand urgent international and national level scientific attention, policy and planning. It is our own responsibility to conserve our natural heritage without any delay. Sri Lanka has various wetland ecosystems, both natural and man-made, that support its biodiversity (Bambaradeniya, 2002). The importance of conservation of wetland ecosystem is recognized globally. Wetland habitats are highly productive and diverse communities that lie between terrestrial and aquatic environments (Goonatilake et al., 2001). Wetlands in Sri Lanka, covering 274, 000 ha, may be categorized as; inland freshwater wetlands (rivers, streams, marshes, swamp forest, villus), saltwater wetlands (lagoons, estuaries, mangroves, sea grass beds, coral reefs), man-made wetlands (tanks, reservoirs, rice fields, salterns) (IUCNSL, 2004). Bellanwila-Attidiya Sanctuary Bellanwila-Attidiya Sanctuary (BAS) is listed in the directory of Asian wetlands by the IUCN in 1989 and designated as an Important Bird Area by Birdlife International (www.birdlife.org, accessed 7/8/2009). It was declared a sanctuary under the fauna and flora protection ordinance by gazette extraordinary No. 620/9 of 25th July 1990 (Gunawardana, 1991). BAS is situated within the upper catchments of the Bolgoda river basin. The core study area is roughly 1–2 km x 0.5 km (nearly 372 ha), at a mean elevation of 0.6 m above sea level. BAS area lies at the intersection of 6 48’-52’ N and 79 52’-56’ E (IUCNSL & CEA, 2006; Maduranga, 2005). This area is situated within the low country wet zone and has a tropical monsoonal climate (Gunatilleke & Gunatilleke, 1990). Mean annual temperature is approximately ~28 C and average annual rain fall for the study area is about 2800 mm (CEA / Euroconsult, 1993). The Bellanwila-attidiya sanctuary was surveyed by various conservationists and scientists from the early 1980’s (CEA / Euroconsult, 1993; Dissanayaka & Mahaulpaha 2006; Goonatilake, 1998; Goonatilake et al., 2001; Gunatilleke, 1992; Gunawardana, 1991; Henkanaththegedara et al., 2005; Maduranga, 2005; Nalinda, 1988; Nanayakkara, 1988). The BAS marsh consist of several habitat types which can be categorized as shallow freshwater ponds, canals, marshes, seasonally flooded grasslands, scrublands, and paddy fields. The survey was expanded to include a man-made reservoirs, home gardens, scrublands and grasslands immediately outside its boundary (Henkanaththegedara et al., 2005). The vegetation of BAS area is mainly composed of rooted emergents such as Rhyncospora sp., Eleocharis sp., and grasses such as Brachiaria sp., Bacopa sp. that grow extensively along the fringes of ponds KARUNARATHNA ET AL., 2010 50 TAPROBANICA VOL. 02: NO. 01 (Maduranga, 2005). The water surfaces are covered with Salvinia molesta, Eichhornia crassipes and flowering ornamental species such as Nymphaea sp. and Nelumbo nucifera. The margins of marshy areas and the banks of the canal are covered with mixed vegetation of Annona glabra, Cerbera manghas, Syzygium sp., Melastoma sp. (Henkanaththegedara et al., 2005). Invasive alien species such as Lantana camara are also common. Materials and Methods Data were collected from random field observations during a number of visits from June 2005 to June 2006 (one year study). A summary of these data were previously posted on the Environment Sri Lanka Blog (Karunarathna, 2008). Visual encounter survey methods were used in preparing this faunalist. The fish faunal data were collected from the catches of fishermen using cast nets, hooks, ropes and gill nets. In addition, fish in shallow areas were sampled by using small trawl nets and hand nets. The avifaunal data were collected by using a standard binocular, and by calls and songs. Mammal fauna were documented through direct observations and indirect methods (eg. foot prints). Amphibian and reptile (Herpetofauna) data were assembled by collecting road kills and specimens killed by villagers and by searching under logs, stones and boulders. Several nocturnal field visits were also made in walking throughout the study area. Some small butterflies were captured using a butterfly net and closely observed using a clear glass bottle. Vertebrates and invertebrate species were identified and classified by using published field guides (for freshwater fishes – Maduranga (2003), Pethiyagoda (1991), but later some species were confirmed by Silva et al. (2008; 2010), Pethiyagoda et al. (2008a; 2008c); Amphibians – Dutta & ManamendraArachchi (1996), Manamendra-Arachchi & Pethiyagoda (2005), Manamendra-Arachchi & Pethiyagoda (2006); Reptiles – Das & de Silva (2005), Deraniyagala (1953; 1955), de Silva (1990), De Silva (1980), Whitaker & Captain (2004); Birds – Harrison (1999), Rasmussen & Anderton (2005); Mammals – Phillips (1980); Butterflies – D’Abrera (1998), Woodhouse (1952), Kunte (2006). Threatened categories were assigned according to IUCNSL & MENR (2007) and some floral species were identified by Ashton et al. (1997). Threats Considerable land area of BAS wetland has been lost due to: (01) Habitat fragmentation (02) Changes in water level that degraded native vegetation habitat and provided access for invasive native and non-native weeds and accelerated the succession decline of BAS habitat. (03) Excess run-off of sediment, fertilizer, industrial waste, human sewage, animal waste, road salts, pesticides, heavy metals, leakage from landfills and dumps, toxic pollutants and nutrients that pollute wetlands and it exceeded the wetland's natural ability to absorb such pollutants and cause degradation. The extra nutrients are rapidly taken up by some types of aquatic plants such as Eichhornia crassipes. As the numbers of these plants increase, they become dominant over plants living on the sediment. (04) Plant and animal pest invasion. (05) Livestock grazing in surrounding catchments and in the BAS we

Because of the paucity of biological inventory in many regions of the country, other extinctions may have gone unnoticed.Indeed, since new species are still being described, it is possible that some species may go extinct before becoming known to science.It is alarming that human population density in our biologically richest wet zone is one of the highest on earth.Also, the population is growing more rapidly than average around protected areas (Wittemyer et al., 2008), a trend that seriously threatens the remaining biodiversity trapped in forest reserves and this is perhaps true for Sri Lanka.Although the Western Ghats and Sri Lanka is a biodiversity hotspot for conservation priorities (Myers et al., 2000;Mittermyer et al., 2004), unfortunately it is one of the most populous identified (Cincotta et al., 2000).Recent research highlighted the uniqueness of the Sri Lankan fauna from the mainland (Bossuyt at al., 2004;Bossuyt et al., 2005;Helgen & Groves, 2005).Therefore, we need to conserve and protect our natural wealth more aggressively than we have so far.
Several Sri Lankan animal and plant taxa not only contain assemblages of endemics, but these sometimes constitute old branches or distinct clades of the tree of life (Bossuyt et al., 2004;Roelants et al., 2004).This is significant because radiations of tens of species are found exclusively on Sri Lanka (Bossuyt et al., 2005;Gunawardene et al., 2007;Helgen & Groves, 2005;Meegaskumbura et al., 2002).Therefore, conservation managers could treat these clades of animals and plants as the island's major natural treasure (Bossuyt et al., 2005).Protecting these endemic taxa as "umbrella species" would result in protection of other rare and endangered species.It is in that perspective noteworthy that Sri Lanka's diversity largely restricted to the formerly rain-forested southwestern wet zone, knuckles mountains and the central hills where only a little natural forest with many of the endemics now survive, beset by invasive alien species of plants and surrounded by plantations and settlements.The threats to the unique biodiversity recognized and the challenges to its conservation are therefore formidable and demand urgent international and national level scientific attention, policy and planning.It is our own responsibility to conserve our natural heritage without any delay.

Bellanwila-Attidiya Sanctuary
Bellanwila-Attidiya Sanctuary (BAS) is listed in the directory of Asian wetlands by the IUCN in 1989 and designated as an Important Bird Area by Birdlife International (www.birdlife.org,accessed 7/8/2009).It was declared a sanctuary under the fauna and flora protection ordinance by gazette extraordinary No. 620/9 of 25th July 1990 (Gunawardana, 1991).BAS is situated within the upper catchments of the Bolgoda river basin.The core study area is roughly 1-2 km x 0.5 km (nearly 372 ha), at a mean elevation of 0.6 m above sea level.BAS area lies at the intersection of 6 o 48'-52' N and 79 o 52 '-56' E (IUCNSL & CEA, 2006;Maduranga, 2005).This area is situated within the low country wet zone and has a tropical monsoonal climate (Gunatilleke & Gunatilleke, 1990).Mean annual temperature is approximately ~28 o C and average annual rain fall for the study area is about 2800 mm (CEA / Euroconsult, 1993).

Materials and Methods
Data were collected from random field observations during a number of visits from June 2005 to June 2006 (one year study).A summary of these data were previously posted on the Environment Sri Lanka Blog (Karunarathna, 2008).Visual encounter survey methods were used in preparing this faunalist.The fish faunal data were collected from the catches of fishermen using cast nets, hooks, ropes and gill nets.In addition, fish in shallow areas were sampled by using small trawl nets and hand nets.The avifaunal data were collected by using a standard binocular, and by calls and songs.Mammal fauna were documented through direct observations and indirect methods (eg.foot prints).Amphibian and reptile (Herpetofauna) data were assembled by collecting road kills and specimens killed by villagers and by searching under logs, stones and boulders.Several nocturnal field visits were also made in walking throughout the study area.Some small butterflies were captured using a butterfly net and closely observed using a clear glass bottle.

Threats
Considerable land area of BAS wetland has been lost due to: (01) Habitat fragmentation (02) Changes in water level that degraded native vegetation habitat and provided access for invasive native and non-native weeds and accelerated the succession decline of BAS habitat.
(03) Excess run-off of sediment, fertilizer, industrial waste, human sewage, animal waste, road salts, pesticides, heavy metals, leakage from landfills and dumps, toxic pollutants and nutrients that pollute wetlands and it exceeded the wetland's natural ability to absorb such pollutants and cause degradation.The extra nutrients are rapidly taken up by some types of aquatic plants such as Eichhornia crassipes.As the numbers of these plants increase, they become dominant over plants living on the sediment.
(05) Livestock grazing in surrounding catchments and in the BAS wetlands that damages vegetation, decreases soil stability and adds to pollution.
(06) Loss of natural character (i.e. the natural appearance of wetlands in the landscape) and changes in plant dominance have profound effects on the animals that depend upon aquatic environments as a source of food and refuge and as a nursery for their young.
(07) Hunting and carelessness human activity disturbs plant and animal life and may destroy parts of the physical wetland environment.
(08) Inappropriate use of surrounding land in a catchment (eg.poorly managed farming practices causing sedimentation and/or fertilizer run-off).
(09) Land filling and drainage of wetlands for urban or rural development.
Although legislation has greatly slowed wetland loss, the above sources of degradation continue.

Results and Discussion
The present study, the first to comprehensively document biodiversity within BAS, recorded 152 species of vertebrate fauna, 75 species of butterflies from BAS (Table -1).Of the total number of species recorded, 16 (7%) are endemic, while 5 (~2.2 %) are nationally threatened (IUCNSL & MENR, 2007).The vertebrates comprised 11 (7.2%) species of amphibians, 27 (17.8%)species of reptiles, 14 (9.2%) species of mammals, 78 (51.3%) species of birds, 22 (14.5%)species of fishes.Birds were the most abundant faunal group in Bellanwila-Attidita Sanctuary, according to the present survey; amphibian and mammals were the least abundant faunal groups.Among them 12 (5.2%)are near threatened and 4 (1.7%) species are data deficient.The amphibians consisted of 11 species (3 endemics) belonging to 5 families (Appendix -1), including toads, narrow-mouthed frogs, aquatic frogs and tree frogs.These represented approximately 10.1% of the total amphibian species in the island.Among them, 5 species are very common, they are Duttaphrynus melanostictus, Euphlyctis cyanophlyctis, Euphlyctis hexadactylus, Hoplobatrachus crassus and Philautus popularis, while 3 species are very rare at BAS, they are Microhyla rubra, Hylarana gracilis and Polypedates cruciger.Most of these species could be observed after a short spell of rain at night.However, no nationally threatened species were recorded in the BAS.According to Goonatilake et al. (2001) 15 species of amphibians were recorded in BAS area, but we failed to record Duttaphrynus atukoralei, Hylarana aurantiaca, Sphaerotheca rolandae, Philautus leucorhinus and Philautus variabilis.The latter 2 species are currently known as extinct.Philautus popularis was the only shrub frog recorded in BAS.Amphibians play a vital role in the functioning of natural ecosystems.Because they consume a large biomass of insects they act as natural control agents of pests in both human settlements and agricultural landscapes.
The reptiles consisted of 27 species (6 endemics) belonging to 10 families (Appendix -2), covering 13% of the island reptiles fauna.These included 11 species of tetrapod reptiles and 16 species of Serpentoid reptiles.Among the total species, 2 species are near threatened.The snakes, both venomous and non-venomous, are widely killed in BAS due to fear and ignorance, as a precaution against snakebite.Also, several road kills were recorded during the study period, such as: Cylindrophis maculata, Coeloganthus helena, Oligodon sublineatus and Sibynophis subpunctatus.But no record of any sea snake species in the BAS area.The reptile family in which the largest number of species was recorded was Colubridae.
A total of 14 species of mammals, belonging to 9 families, were recorded in BAS (Appendix -3), covering 13.9% of the island mammal fauna.These include the vulnerable Prionailurus viverrinus.No endemics were recorded.The mammals have diverse food habits, and could be categorized as granivorus, frugivorous, carnivorous and insectivorous.Pteropus giganteus, Herpestes brachyurus, Herpestes edwardsii, Bandicota bengalensis, Bandicota indica, Rattus rattus and Funambulus palmarum were the most common mammals, while Kerivoula picta and Hystrix indica were very rare in BAS.According to Goonatilake (1998), 27 species of mammals were recorded in BAS area, but we failed to the record Lutra lutra, Moschiola kathygre, Canis aureus, Prionailurus rubiginosus, Mus musculus, Golunda ellioti, Lepus nigricollis, Semnopithecus vetulus, Rousettus leschenaultia, Cynopterus sphinx and Hipposideros ater.The rats are often considered as pests because they feed or damage the food and cultivations.A Hystrix indica individual was captured from a canal bank in BAS.The Painted bat is one of the most significant records within this area.
A total of 22 species of fish, belonging to 11 families, were recorded in BAS (Appendix -4), covering 18.2% of the island fish fauna.Few native species were recorded in study area; most were nonnative, such as the invasive alien species Pterygoplichthys multiradiatus.Out of these 22 species, 1 is vulnerable, 1 is near threatened, 1 is data deficient and 2 are endemic.The fish fauna is mainly based in the Thel Ela and Katu Ela area at BAS and others are around the Bellanwila temple.The most common fish species are Oreochromis mossambicus and Pterygoplichthys multiradiatus, while Lepidocephalichthys thermalis and Puntius chola are rare in BAS.These fish form an important component of the diet of aquatic birds such as Pelecanus philippensis and Phalacrocorax fuscicollis in BAS.According to Maduranga (2005) and Nalinda (1988), 33 fish species were recorded in BAS area, but we failed to the record Megalops cyprinoides, Amblypharyngodon melettinus, Esomus thermoicos, Rasboroides atukorali, Puntius vittatus, Mystus keletius, Clarias brachysoma, Aplocheilus dayi, Laubuca sp., Etroplus maculatus and Channa orientalis.Water pollution is major threat to the survival of fishes and habitat loss due to the reclamation of land and destruction of vegetation.It is a fact that the exotic species become dominant in a new habitat when the environmental conditions are conducive.Due to anthropogenic activities, the habitat quality for the resident species might become less favourable so that the exotic species might get a competitive advantage to become an invasive species.According to Vale´ry et al. (2008), a biological invasion consists of a species' acquiring a competitive advantage following the disappearance of natural obstacles to its proliferation, which allows it to spread rapidly and to conquer novel areas within recipient ecosystems in which it becomes a dominant population.
Birds appeared to be the dominant group of vertebrates at BAS, consisting of 78 species (4 endemics) belonging to 38 families (Appendix -5).
BAS has is a paradise for birds, including many migratory species, and these represented approximately 15.8% of Sri Lankan avifauna.Among the total species, 9 winter migrants were recorded, while 1 species (Pelecanus philippensis) is globally threatened and 2 species are near threatened.But we fail to record some interesting birds such as, Pellorneum fuscocapillus, Plegadis falcinellus, Pomatorhinus melanurus and Caprimulgus asiaticus in this study.The mixture of vegetation types and aquatic habitats in BAS has made it an ideal ecotone for a variety of birds, where about half of the birds species recorded were those associated with wetland ecosystems, such as herons, egrets, cormorants, kingfishers and pelicans, all which feed on aquatic organisms.This area an important breeding habitat of native birds, and it is also a preferred feeding and resting habitat of several species.Gunawardana (1991) 153 species of birds were recorded in BAS, but we failed to record even half of them.
We recorded a rich array of butterflies in BAS, including 75 species, belonging to 5 families (Appendix -6).The butterflies represented approximately 30.9% of the total species in the island; 1 species is endemic, 3 species are nationally threatened and 7 species are near threatened.The butterflies are a group of charismatic insects in Sri Lanka, which forms a major component of the island's biodiversity.Among them, Papilio domoleus, Graphium Agamemnon, Leptosia nina, Delias eucharis, Catopsilia pyranthe, Eurema hecabe, Danaus genutia, Junonia atlites, Telicota colon, Acraea violae, Ypthima ceylonica, Jamides celeno and Zizula hylax were the most common.Eurema blanda, Spalgis epeus, Curetis thetis, Zesius chrysomallus, Troides darsius, Tajuria cippus, Charaxes solon, Rathinda amor and Hypolycaena nilgirica were rare at BAS.According to Gunatilleke (1992) and Henkanaththegedara et al. (2005) 61 and 70 were recorded in BAS respectively, but we failed to record Chilades pandava, Lampides boeticus, Nacaduba sinhala, Elymnias singala, Mycalensis mineus, Vanessa cardui and Eurema brigitta species.The distribution of the butterflies in various habitat types needs further investigation and this study is just a beginning and paves the way for further studies.The highest diversity of butterflies was recorded from the open scrub jungles while the lowest close canopy habitats.The largest number of species was from the family Nymphalidae (28 sp.), followed by the families Lycaenidae (19 sp.), Papilionidae (11 sp.), Hesperiidae (11 sp.) and Pieridae (6 sp.).
In each taxon, we failed to record all species that had been recorded in previous studies.In some cases, this might be because the previous studies were more thorough or better sampled all types of habitats and seasons.However, it could also be that the continuing habitat deterioration and encroachment of settlement and human activities, persecution of snakes has actually extirpated some of the species that formerly occurred here.This is certainly the case with the 2 species of amphibians noted above as extinct, We believe that most of the species "missing" in this survey have, in fact, been locally extirpated from the Bellanwila-Attidiya Sanctuary.The habitat deterioration, extinction of at least 2 species (if confirmed by more extensive surveys) and local extirpation of many species, have been caused by poor protection, resulting in the "deplorable state of the Bellanwila-Attidiya Sanctuary, beset on all sides by unauthorized construction, garbage dumping and unsustainable livelihoods…" (Amaleeta, 2006).

Table 01 :
Faunal diversity of Bellanwila-Attidiya Sanctuary and its vicinity BAS