BIODIVERSITY OF THE BUNDALA NATIONAL PARK AND RAMSAR WETLAND

The Bundala National Park (6216 ha) is located in the Hambantota District, within the SoutheasternArid Zone of Sri Lanka. T:lC park consists mainly of dry thorny scrubland and lagoons;Koholankala (390 ha), Malala (6511 ha), Embilikala (430 ha) and Bundala (520 ha). Theseshallow water lagoons form a complex wetland system that harbours a rich bird life, includingseveral species of migratory waterfowl. Bundala is Sri Lanka's first Ramsar wetland-a wetlandof international importance especially for migratory waterfowl. Recent studies have indicatedthat the Bundala National Park and its wetlands are being degraded by various adverse factors,Therefore, this survey was intended to document the present status of biodiversity in thisprotected area, and the threats it faces today. The systematic survey on biodiversity extendedfrom January to April 2001, during which the area was visited at fortnightly intervals, The faunaand flora were surveyed using scientifically valid inventorying techniques. The survey enabledto document 7 major terrestrial vege.ation/habitat types (dry thorny scrubland, Arid zone forests,sand dune vegetation, gentle sea shore vegetation, Arid zone maritime grasslands/pastures,Riverine forest, anomalous Mesquite (Prosopis) scrublands and 6 wetland types (saltmarsh,mangrove, brackish water lagoons, sandy and rocky sea shore, seasonal water holes and tanks,saltern) in Bundala. A total of j83 plant species have been documented from the abovevegetation and habitat types in Bundala, These include 6 endemics and 7 species that areconsidered as nationally threatened. Shrubs and herbs (plants with leaves and non-woody stems)are the predominant plant life forms of Bundala. A total of 324 species of vertebrates have beenrecorded from Bundala National Park, of which 11 species are endemic, while 29 species arenationally threatened. Among the invertebrates are 52 species of colourful butterflies.At present, the biodiversity of Bundala National Park is facing several threats, which could besummarised under habitat deterioration and degradation (i.e., Shell mining, driving of vehiclesoff the recommended tracks, discharge of irrigation water in to lagoons, release of sludge intothe Bundala lagoon), direct exploitation of species (poaching, felling of trees, road kills), spreadof invasive alien species (4 animal species and 15 plant species), prolonged drought, andunplanned land-use practices. It is envisaged that these findings would contribute to theconservation and management of this globally important PA

Altitudinal Variation of the Floristic Communities in Monaragala, an Isolated Hill in Eastern Sri Lanka

Compared to wet zonehills of Sri Lanka, the floristic communities of hills in drier regions ofits first peniplane has been poorly studied. This study investigatedthe floristic communitiesalong the altitudinal gradient in Monaragala, an isolated hill in the intermediate zone of theisland, by sampling trees and lianas >10 cm g bh, in 99 randomly located 10 m x10 m plots infour transects laid on different aspects of the hill.In the 9,900 m2 sampled in the study, 1,322 individuals were enumerated. They represented44 families, 103 genera and 149 species, among which 45 were endemic to Sri Lanka. Frommultivariate analysis of the plot data, one grassland / savanna and five forest communitiesseparated in relation to their variations in elevation and topography, disturbance level andphysiognomy of the vegetation. These communities were: two disturbed tall forests, onerestricted to low-elevation 210-780 m (LDT) and the other widespread at 540 – 620 m / 920 –950 m (WDT); three undisturbed tall forests, one at mid-elevation 600-880 m (MUT) and theother two on ridge slopes of Sirigala (RUT) and Maragala (IUT) at 880 -1100 m, and the lasta high-elevation disturbed grassland/savanna at 720 – 870 m (HDG).The five leading families in each of the six communities collectively represented 31 of the 44families identified in the study, reflecting familial diversity among the communities. Thedominant families were Sterculiaceae and Rutaceae in the lower elevation, while Lauraceae,Dipterocarpaceae, Myrtaceae, Bombacaceae and Apocynaceae were in mid - and upperelevations. Euphorbiaceae was common to all altitudinal ranges.Most species were restricted to a particular elevation range. At the lower range, Diospyrosebenum, Pterospermum suberifolium, Miliusa indica, Acronychia pedunculata, Alphonseasclerocarpa, Chlorocarpa pentaschista and Drypetes sepiaria. The mid- and higher rangeharboured endemic species and those common to wet zone rainforests, eg. Actinodaphneelegans, A. ambigua, Cullenia ceylanica, Cryptocarya wightiana, Hunteria zeylanica,Calophyllum tomentosum, Dipterocarpus zeylanicus.This study emphasizes that isolated hill forests located outside the wet zone, like Moneragala,harbour diverse and unique floral assemblages which need urgent conservation in a rapidlydeveloping era.

BIODIVERSITY OF THE MADUGANGA MANGROVE WETLAND

The Maduganga estuary and mangrove islets are a complex coastal wetland ecosystem situatedwithin the two Divisional Secretariats of Balapaitiya and Karandeniya in the Galle District ofSouthern Sri Lanka, The total area of the estuary is 915 ha, of which 770 ha consist of openwater, while islands account for 145 ha. With the view of safeguarding the ecological functions,resources and values of the Maduganga estuary fer conservation and future sustenance ofbiodiversity, meN Sri Lanka carried out a systematic assessment of biodiversity in Maduganga.A six-month field survey was conducted from May to October 2000. Field sampling was carriedout at fortnightly intervals' each sampling session spanning over six continuous days. TheMaduganga ecosystem was divided into six major Si rata based on the occurrence of differentvegetation types, human activities and a hypothetical salinity gradient. These strata weresampled for fauna and flora in a systematic manner, using standard techniques. The threats tobiodiversity were also assessedThe survey revealed that the Maduganga wetland consists of 10 major wetland vegetation types.These vegetation types harboured a total of 303 species of plants belonging to 95 families. Thetotal plant species included 19 endemics, 8 nationally threatened species and 9 invasive alienspecies. Based on the extent of occurrence (ha), mangroves and mangrove mixed swamps werethe dominant wetland vegetation types in Maduganga, In addition to these wetland vegetationtypes, three major terrestrial vegetation types are also found in the islands and the surroundingmainland area of the Maduganga estuary. Perennial crops (mainly cinnamon) dominated theterrestrial vegetation types. A total of 98 plant species were recorded from the multi-specieshome gardens. When considering the species richness of flora in different wetland vegetationtypes, mangroves harboured the highest number of species, closely followedby mangrove mixedswamps. Maduganga estuary harbours a small population of a very rare, threatened mangrovespecies Lunmitzera littorea. A total of 248 species of vertebrate fauna, belonging to 121 familieswere recorded from Maduganga. These included 20 species (8%) of endemics, while 30 species(12%) are considered as nationally threatened. The native vertebrate fauna of Madugangarepresents 30% of Sri Lanka's native inland vertebrate species.Maduganga, perhaps one of the last remaining tracts of pristine mangrove forest in Sri Lankawith a rich biodiversity, now appears to be threaten,~c:.with the same predicament that many ofthe island's mangroves now find themselves in, owing to increasing human activity. At present,this wetland is not a protected area under any government department. Therefore, it is envisagedthat the findings of this survey will contribute to the .x'nservation of this unique coastal wetland.