Avifaunal diversity in the peripheral areas of the Maduruoya National Park in Sri Lanka: With conservation and management implications

Published Date
Journal of Asia-Pacific Biodiversity
30 June 2015, Vol.8(2):121–132, doi:10.1016/j.japb.2015.04.005
Open Access, Creative Commons license, Funding information
Original article

• Author 

• Dinesh E. Gabadage ^a
• W. Madhava S. Botejue ^a
• Thilina D. Surasinghe ^b
• Mohomed M. Bahir ^a
• Majintha B. Madawala ^c
• Buddhi Dayananda ^d
• Vimukthi U. Weeratunga ^e
• D.M.S. Sameera Karunarathna ^f,,

• aBiodiversity Conservation Society, Number 150/6, Stanly Thilakaratne Mawatha, Nugegoda, Sri Lanka
• bDepartment of Biology, Gustavus Adolphus College, St. Peter, MN, USA
• cSouth Australian Herpetology Group, South Australian Museum, North Terrace, Adelaide, SA, Australia
• dGemunu Mawatha, Rambukkana, Sri Lanka
• eDutugemunu Mawatha, Talahena, Battaramulla, Sri Lanka
• fNature Explorations and Education Team, Moratuwa, Sri Lanka

Received 9 March 2015. Revised 15 April 2015. Accepted 27 April 2015. Available online 5 May 2015. 

Abstract

A survey was randomly conducted in the marginal areas of Maduruoya National Park, Sri Lanka for a period of > 7 years. These study sites are located within the dry zone and the intermediate zone. The main vegetation type of the area is dry mixed evergreen forest. We recorded 196 bird species belonging to 66 families, and they included 161 breeding residents, 25 purely migrants, nine both resident and migrants, one vagrant, 14 nationally threatened, three globally threatened, and 10 endemic species. We also report the first-ever records of Chestnut-backed Owlet, Red-faced Malkoha, and Spot-winged Thrush from this dry area. However, these precious habitats and its species are threatened because of irresponsible human activities such as forest fires, land filings, hunting, road kills, encroachments, garbage dumping, agrochemicals, granite-rock blasting, logging, and road constructions. Therefore, we recommend that relevant authorities take immediate conservation action to increase the protection of these marginal areas or buffer zone in the near future.

Keywords

Dry zone forest

Fortification

Migrant birds

Red list category

Threatened birds

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Introduction

The tropical Island of Sri Lanka (5°55′–9°51′ N and 79°41′–81°54′ E) has a rich and diverse assemblage of avifauna that comprises a total of 453 species with 240 breeding residents and 213 purely migrants including 72 vagrants (Weerakoon and Gunawardena, 2012 and Warakagoda et al., 2012). Among Sri Lanka's residential breeders, 21 species are also represented by migrating populations (Weerakoon and Gunawardena 2012). The number of endemic species has been disputed, and the number has fluctuated between 20 and 47 throughout the ornithological history of Sri Lanka (Kotagama et al 2006). Some ornithologists list 33 endemic species (Rasmussen and Anderton, 2005, Warakagoda and Sirivardana, 2009 and Weerakoon and Gunawardena, 2012), whereas others consider 27 species as being definitive endemic and the remaining six species as proposed endemics (Kaluthota and Kotagama, 2009, Kotagama et al., 2006 and Weerakoon and Gunawardena, 2012). At present, 67 species including 18 endemic species are categorized as “nationally threatened [Critically endangered (CR), Endangered (EN), and Vulnerable (VU)] according to the National Red List 2012 of Sri Lanka (MOE 2012). The distribution and habitat preference of the birds within the island of Sri Lanka are primarily governed by the vegetation and geoclimatic parameters such as temperature variability, precipitation, hydrology, and altitude (Harrison and Worfolk, 2011 and Kotagama et al., 2006). Some avifauna are island-wide in distribution, whereas for others a substantial proportion are only recorded from one or two bioclimatic zones (Warakagoda et al 2012). For instance, more than 60% of the residential species are restricted to the southwestern wet zone (annual average precipitation, >2000 mm) and the central highlands of Sri Lanka (Weerakoon and Gunawardena 2012).

Approximately one-third of residential breeders of Sri Lanka are forest birds (Weerakoon and Gunawardena 2012). Sri Lanka's forest covers constitute ∼25% of the total land area (FAO 2010). Both primary and secondary forests in the island are rapidly diminishing and being severely fragmented as a result of expanding human settlements and agricultural lands, leading to adverse impacts on the rich native biodiversity (Bambaradeniya et al., 2003 and Senanayake et al., 1977). Natural vegetation in Sri Lanka is represented by an adverse array of forest types with dry mixed evergreen forests, lowland evergreen rainforests, and moist montane forests being the most predominant (Gunatilleke and Gunatilleke 1990). The dry mixed evergreen forests of the dry zone (annual average precipitation, < 2000 mm) are the most extensive, covering 21% of the island (Wikramanayake et al., 2001 and FDGSL, 2009). These forests are largely secondary in origin (resulting from secondary successions following abandonment of prehistoric agriculture and human civilizations), and distributed across most of the dry zone except in the Jaffna peninsula (Gunatilleke and Gunatilleke, 1990 and SDSL, 2007). They have a mean annual temperature ∼29°C, and the mean annual rainfall is ∼1000–1500 mm. Most of the rain falls during the northeast monsoon season from October to February, and there is a noticeable dry period from May to August (Gunatilleke and Ashton, 1987and SDSL, 2007). The dry zone topography can be described as flat lowlands not exceeding 300 m (the 1^st peneplains). However, there is some high-elevation, rock-outcrop vegetation in a few isolated, residual peaks of the dry zone (SDSL 2007).

Because a substantial proportion (> 30%) of Sri Lanka's avifauna is composed of forest species, monitoring the status of bird communities through surveys and implementing conservation actions are foremost in importance (Kotagama et al., 2006and Weerakoon and Gunawardena, 2012). The dry mixed evergreen forests of the north, north-central, and eastern regions of Sri Lanka remained relatively unexplored for about the past 30 years (1976–2009) owing to national security complications and civil unrests (Weerakoon and Gunawardena 2012). Given the greater spatial coverage of dry mixed evergreen forests in Sri Lanka, and the anthropogenic stressors that could potentially endanger these ecosystems, we intended to explore the avifaunal diversity in the vicinity of the Maduruoya National Park, a poorly-studied region covered with extensive dry mixed evergreen forests. Most faunal surveys in Sri Lanka has taken place inside protected areas with little to no attention given to the peripheral forests outside the park or reserve boundaries. Previous studies have underscored the importance of habitats surrounding the protected areas for the persistence of the native bird populations inside the park boundary (Wijesinghe and Brooke, 2005 and Gunawardene et al., 2007). Our objectives for this investigation were (1) to assess the bird diversity of the habitats bordering the Maduruoya National Park, (2) to identify threats that might endanger the native bird fauna of the region, and (3) to suggest conservation recommendations for the habitats adjoining the national park and to improve the habitat quality of the buffer area.

Materials and methods

Study area

Peripheral habitats around Maduruoya National Park are similar to those inside the park. Our study area is located within the dry zone with the southern edge of our study area bordering the intermediate bioclimatic zone (Figure 1), with close proximity to the Mahaweli development region (a government-sponsored, large-scale socioeconomic development scheme involving irrigation and reservoir construction through impoundments, establishment of human settlements, and infrastructure development), teak plantations, and unprotected woodlands that are subjected to repeated slash-and-burn cultivation (DWC, 2004 and IUCN, 1990). The Maduruoya National Park (∼58,850 ha; 7°23′–7°35′ N and 81°05′–81°20′ E) was established in the year 1983 (Gazette No. 270/9) under the Fauna and Flora Protection Ordinance as an integral part of the Mahaweli Protected Area Complex to provide habitats for the displaced wildlife and provide refuge for many other native fauna and flora, particularly elephants (DWC, 2004, IUCN, 1990 and SDSL, 2007). The Maduruoya National Park and surrounding areas also serve as a catchment for five regional reservoirs (Henanegala, Maduruoya, Pimburettawa, Ratkinda, and Ulhitiya) developed under the Mahaweli Programme (DWC, 2004 and IUCN, 1990).

Figure 1. Map of the study area, located in North Eastern dry and intermediates zones of Sri Lanka, with different habitat types.

Department of Wildlife Conservation of Sri Lanka (2004). A guide to national parks of Sri Lanka, Department of Wildlife Conservation, Colombo, Sri Lanka.

The main vegetation type of the area is tropical dry mixed evergreen forests “dominated by Manilkara sp.” (Gunatilleke and Gunatilleke 1990). Given the forest regeneration aftermath of historical chena farms (a form of shifting agriculture) and early settlements, our study region has large areas of secondary vegetation and vast extensions of open dry tropical grasslands and wooded, lowland savannas (Premadasa 1990), and large wetlands (Figure 2A). The local topography can be described as mainly flat lowlands ranging from 30 m to 150 m in altitude, reaching a maximum at 685 m, and an 8-km stretch of rock-outcrop vegetation located southwest of Maduruoya National Park (Figure 2B). The mean annual temperature of our study area is ∼27°C, and the mean annual rainfall is 1650 mm—received mostly during the northeast monsoon (from October to late January) season (DWC, 2004 and IUCN, 1990). The Maduruoya National Park is not only significant from a biodiversity perspective but is also extremely rich in its archeological heritage, housing a number of ruins and artifacts dating back to various periods of Sri Lanka's imperial history.

Figure 2. A, Man-made wetlands for agricultural practices (mainly for rice fields); B, Rock-out vegetations, with the electric elephant fence in border an around Maduruoya National Park (photos: Madhava Botejue).

Data collection

We conducted this survey for > 7 consecutive years (2007–2014). Our survey was based on a total of 36 field visits to multiple habitats adjoining Maduruoya National Park boundary (2 km buffer zone). We made observations through the unaided eye and (8 × 40) Nikon binoculars (Nikon Vision Co., Ltd. Tokyo, Japan) via multiple random walks. We used a Cannon EOS 50D SLR (Canon Inc., Tokyo, Japan) digital camera to take photographs and a Taylor digital thermometer (Taylor Precision Products Inc., Oak Brook, IL, USA) to measure and record some environmental parameters. The Global Positioning System (GPS) coordinates were recorded using a Garmin Etrex 10 GPS receiver (Garmin International, Inc., Olathe, KS, USA), and the habitat map was made by using Arc Gis version 10.1 (Esri, Redlands, CA, USA) software. Indirect observations such as calls and presence of plunged (or dropped) feather, nests, and eggs were also recorded. Our survey encompassed diverse habitat types (wetlands, scrublands, grasslands, home gardens, homestead, farmlands, and teak plantations) that are closely associated with dry mixed evergreen forests. Surveys were conducted during both day and night (from 0600 hours to 0800 hours in the morning, from 1400 hours to 1600 hours in the afternoon, and from 2000 hours to 2200 hours in the night). We also interviewed villagers using our own questionnaire forms to assess their forest needs. All the bird species were identified with reference to Harrison and Worfolk, 2011, Henry, 1998 and Kotagama and Fernando, 1994, and Rasmussen and Anderton (2005). The classification, nomenclature, and common names of the checklist were compiled according to Rasmussen and Anderton (2012) and Birdlife International (2014a). According to Warakagoda et al (2012), species common names containing “Ceylon” are upgraded to “Sri Lanka”. The migratory and/or residential status was accorded with Rasmussen and Anderton (2012) and Warakagoda et al (2012). The national conservation status (Red List) is in accordance with MOE (2012), and the global conservation statuses are in accordance with IUCN (2014). The habitat types were determined according to the Birdlife International (2014b). The relative diversity (RDi) of orders was calculated using the following formula:

RDi = number of bird species in an order/total number of species × 100.

Results

We recorded a total of 196 species of birds representing 66 families and 20 orders (Appendix 1); it represents ∼43% of the islands' native bird fauna. Among the avifauna of our study area, 161 (∼82%) were breeding residents including 10 (∼5%) endemics, 25 (∼12%) were purely migrants, one vagrant, and nine (∼5%) species with mixed resident–migrant status (Figure 3A). Among the recorded species, 14 were “nationally threatened” (1 CR, 3 EN, and 10 VU), three were VU, and 27 near threatened (19 nationally and 8 globally) according to the International Union for Conservation of Nature (IUCN) Global Red List. Furthermore, 156 of the recorded species were forest birds (of which 17 were migrants and 7 were mixed residents–migrants); 134 used croplands (of which 17 were migrants and 7 were mixed residents–migrants) (Figure 3B); 44 used built-up areas (of which 7 were migrants and 3 were mixed residents–migrants); 88 used scrublands (of which 12 were migrants and 1 was mixed resident–migrant); 68 used grasslands (of which 10 were migrants and 3 were mixed residents–migrants); 91 were inland aquatic birds (of which 14 were migrants and 6 were mixed residents–migrants). We also calculated species diversity abundance within bird orders (Table 1).

Figure 3. A, Avifaunal richness around Maduruoya National park and the surrounding areas represented based on the migratory and residential status; B, Avifaunal diversity of the Maduruoya National Park and the surrounding areas represented based on habitat types. (AQU = inland aquatic; BRE = breeding recidents; BUL = built-up; CRO = croplands; END = endemics; FOR = forested; GRA = grasslands; MBR = mixed breeding recidents and migrants; MVA = migrants and vagrants; POA = poaching; SCR = scrublands; THR = threatened).

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