Species diversity and conservation of avifauna in three different
habitat types within the Mihintale Sanctuary, Sri Lanka
Chathurabhani Wimalasekara 1 & Sriyani Wickramasinghe 2
1,2 Department of Biological
Science, Faculty of Applied Sciences, RajarataUniversity of Sri Lanka, Mihintale, Sri Lanka
1 sriwick@gmail.com (corresponding author), 2 c.wimalasekara@yahoo.com
Abstract: The present study was carried out in
three different habitat types within the MihintaleSanctuary, namely aquatic, undisturbed forest and disturbed habitat from
November 2008 to May 2009. The main
objective of the study was to determine the species diversity and identify the
threats to the birds. Line
transect, point counts and opportunistic survey methods were conducted daily
both in the morning and evenings. A
total of 130 species of birds belonging to 47 families including 111 breeding
residents, 19 winter visitors, four endemic species and four species that are
being proposed as endemic species were recorded. It also included 10 rare
species, one very rare winter visitor, Zoothera citrina, six nationally threatened and one
globally threatened species, Pelecanus philippensis. The number of bird species that were
observed in the aquatic habitat, forested habitat and the disturbed habitat
were 93, 40 and 76 respectively. The results indicate that diversity of birds
was significantly higher (p<0.05) in the aquatic habitat. It was revealed that the aquatic habitat
provides more suitable niches and food resources for a wide variety of birds.
Therefore, species diversity near aquatic habitat was higher compared to that
of the forest. Fragmentation of
forest into small patches, hunting birds for food and presence of natural
predators are the major threats to the avifauna in the sanctuary. Thus, strategies should be developed to
conserve the avifaunal diversity in the forest patches. The sanctuary supports different types
of native bird species of Sri Lanka and is identified as one of the IBAs in Sri
Lanka, it therefore plays an important role in the conservation of birds in Sri
Lanka.
Keywords: Avifauna, conservation, diversity,
endemic, fragmentation, Mihintale Sanctuary.
doi: http://dx.doi.org/10.11609/JoTT.o3119.5718-25 | ZooBank:urn:lsid:zoobank.org:pub:97A2F141-73DF-4937-9385-03C525605D80
Editor: C.Srinivasulu, Osmania University, Hyderabad,
India. Date
of publication: 26 May 2014 (online & print)
Manuscript details: Ms #
o3119 | Received 11 March 2012 | Final received 09 May 2014 | Finally accepted
12 May 2014
Citation: Wimalasekara, C. & S. Wickramasinghe (2014).Species diversity
and conservation of avifauna in three different habitat types within the Mihintale Sanctuary, Sri Lank. Journal
of Threatened Taxa 6(5): 5718–5725; http://dx.doi.org/10.11609/JoTT.o3119.5718-25
Copyright: © Wimalasekara & Wickramasinghe 2014. Creative
Commons Attribution 4.0 International License. JoTTallows unrestricted use of this article in any medium, reproduction and
distribution by providing adequate credit to the authors and the source of
publication.
Funding: Faculty of Applied Sciences, Rajarata University of Sri Lanka.
Competing Interest: The
authors declare no competing interests.
Acknowledgements: We thank the
Department of Biological Sciences, Faculty of Applied Sciences, Rajarata University of Sri Lanka
for financial supporting this research. We wish to thank Department of Wildlife
Conservation and Archeology for granting permission
to conduct the research within the sanctuary. We also extend our sincere
gratitude to Prof. S.W. Kotagamafor his guidance during the research.
For figures, images, tables -- click here
Sri Lanka’s avifauna is one of the richest in the whole of Asia (Kotagama & Wijayasingha1998). About 482 bird species were
recorded of which 220 breeding residents and 26 species are endemic to the
country (Kotagama et al. 2006). Sri Lanka was identified as an Endemic
Bird Area (EBA 124) in 1998 (BirdLife International
2008).
Though avifaunal studies were carried out both in dry (most of the southeastern, eastern, and northern parts of the country)
and wet (the mountains and the southwestern part of
the country) climatic zones of Sri Lanka, majority of the previous avifaunal
studies were conducted in the wet zone. There is very little information about the avifauna of the sanctuaries
in the dry zone. Mihintale Sanctuary is one of the important sanctuaries located
in the dry zone with very little information on its avifauna. The present study aims to identify the
species diversity and conservation status of bird species in three different
habitat types namely aquatic, undisturbed forest and disturbed areas within theMihintale Sanctuary.
Materials and Methods
The Mihintale Sanctuary (as gazetted on
27/05/1938 in the Sri Lanka Government Gazette No.8370 (Department of
Government Printing 1938)), is situated in Kanadara Korale of Nuwaragam Palatha in the Anuradhapura
District of the North-Central Province and encompasses an area of 2,470acres
(999.6ha). There are no proper
demarcated boundaries for the sanctuary. It receives an annual rainfall of
1,000–1,500 mm/year from the north-east monsoon
and intermonsoons (March-April and
September-October). The main source
of livelihood of the residents is Chena cultivation (slash and burn)
(Divisional Secretary 2007).
MihintaleSanctuary comprises mainly of undisturbed areas of semi deciduous forest
type. Scrublands, water-edge
habitats, highly degraded tertiary forests, and vegetation in archaeological
sites are also found. Surveys to study the
avifauna in three different study sites namely, aquatic habitat and
surroundings near ‘Kudakirindegama Wewa’ (KK) (about 6ha) (8020’36.518’’N & 80031’34.034’’E), Kaludiyapokuna forested area (KP) (about 05ha) (8020’51.752’’N
& 80030’27.498’’E) and cleared up forest areas of Mihintale Hill (MH) (about 05ha) (8021’13.893’’N
& 80030’34.711’’E) (Fig. 1) were taken up. The study was conducted from
0600–0800 hr and 1600–1830 hr in the morning and in the evening, respectively. Line transect method (200x50 m) was used
for sampling terrestrial habitats while point counts were used for sampling
aquatic habitats (Bibby et al. 1993). Four fixed points were selected in
aquatic habitats and 20–30 minutes were spent during both the point and
the transect count methods. The
opportunistic observation method was used since some bird species in the
sanctuary could not be observed along the line transects or points. A pair of binoculars (Bushnell 13-1056C)
was used to identify the birds at a distance and a tally counter was used to
count the number of birds sighted. Species identification and nomenclature was based on Kotagama& Fernando (1994) and Harrison (1999).
Shannon-Wiener Diversity Index was calculated using Microsoft Excel in
order to determine the species diversity. Two-way ANOVA was done to compare the avifaunal samples of each habitat
using statistical software (MINITAB version 14).
Results
A total of 130 birds belonging to 47 families were recorded during the
seven-month period from November 2008 to May 2009. This included 111 breeding residents, 19
winter visitors, four endemic species and four species that are proposed as
endemic birds to Sri Lanka (Kotagama & Ratnavira 2010). Out of 130 birds, 58 species are very common (100% occurrence) and 61
are common, including 10 rare species, one very rare winter visitor, Zoothera citrina(Orange-Headed Ground Thrush), one globally threatened species, Pelecanus philippensis (Spot-billed
Pelican) and six nationally threatened species (Table 1) (Images
1–4). The total number of
bird species observed at KK, KP and MH were 93, 40 and 76, respectively. The proportions of endemic species recorded
as a percentage of the total number of endemic bird species in Sri Lanka were
as follows: KP 11.54% (three species), KK 11.54% (three species) and MH 7.7%
(two species). Shannon Diversity
Index (H’) for KK, KP and MH were 3.83, 3.32 and 3.79, respectively.
The species diversity was significantly high in KK (P=0.000) than the
other sites. When compared to the individual numbers in KK habitat it was
significantly higher (P=0.000) than the other sites (Table 2).
The species composition in the three study areas is as shown in Fig.
2. Thirty-six(27.7%) bird species observed were confined to Kudakirindegamaaquatic area (KK), 21 species (16.15%) to Mihintaledisturbed area (MH) and 12 species (9.23%) were exclusive to Kaludiyapokuna forested area (KP). Thirty-three species
were recorded only at KK and MH, four species were recorded only at KP and MH, six species were recorded only at KK and KP while 18 (13.85%)
species were common to all the three habitats.
Copsychus malabaricus, Nectarinia zeylonica,Oriolus xanthornusare the dominant birds observed at KP. Ardeola grayii, Phalacrocorax fuscicollis, Psittacula kramerii are some of the commonest birds observed
at KK. Pycnonotus cafer, Corvus macrorhynchos and Streptopelia chinensis are the dominant birds identified at
MH.
Discussion
Out of the breeding resident species found in Sri Lanka, 48.9% were
recorded within the sanctuary. So
the species richness of avifauna of the whole sanctuary was quite high. However, the overall endemicityin the sanctuary was relatively low (15.4%) compared to the protected areas in
the wet zone (84.6%). This is
generally the expected result for dry zone habitats (Weerakoon& Goonatilleke 2007). This may be due to the absence of
suitable microclimatic conditions for these endemic birds. But the wet zone rainforests provide
habitats for nearly all of the country’s woody endemic plants and for about
three-quarters of the endemic animals (Ministry of Forestry and Environment
1999). About 20% of the winter
visitors were recorded during this survey.
Species richness and community structure of birds vary from region to
region, as well as within a region, as abiotic and biotic factors vary from
habitat to habitat (Johnsingh & Joshua
1994). Of the three habitat types
present in the sanctuary, highest species diversity was recorded in the KK (H’:
3.83), while the lowest species diversity was recorded in the KP forest (H’:
3.32). According to the vegetation
analysis, 45% of fruiting trees were present in KK while 25% of fruiting trees
were recorded in KP forest. Hence,
this variation in species richness may be due to the structural changes of
vegetation and the availability of food resources. Bird species distribution of an area may
also depend on the insect and biomass of the area (Holmes & Sherry 1997).
These factors may change due to human influences, climatic and topographic
conditions of the area.
Kudakirindegama area
is composed of mainly aquatic habitat and is surrounded by many habitat types
including grasslands, scrub forest, paddy fields etc. These habitat types
provide suitable niches and food resources for many types of birds. Daniels (1989) found an increase in bird
species diversity when forests are disturbed, as in disturbed forests fewer specialist
species and more generalist species are seen, as was observed in MH where the
species richness was high (76 bird species) compared to KP. This can be attributed to the fact that
the primary habitat of KP area is rocky due to which availability of food
resources is low although in certain areas there is presence of good amount of
leaf litter.
Since understory birds are the most sensitive to disturbances in forest
structure, they ought to be reliable indicators of forest regeneration (Wong
1985). Among tropical forest birds,
understory insectivores are particularly sensitive to habitat disturbance and
fragmentation (Sekercioglu et al. 2002). So the bird species like Zoothera citrina, Rhopocichla atriceps, Acrocephalus dumetorum, Pellorneum fuscocapillum, Cyornis tickelliae, Copsychus malabaricus etc, which are found only in KP forested area can be
considered as indicator species for forest fragmentation and disturbance.
Bird species like Columba livia, Corvus macrorhynchos, Hemiprocne coronata, Parus major, Passer domesticus, Lonchura striata are confined
to MH disturbed area and since they live in disturbed habitats are able to
tolerate all the disturbances and pollution caused to the habitat. Fragmentation of large tracks of natural
ecosystems in to small patches is one of the major impediments to long term conservation of biodiversity. Improper land use planning is the
primary cause of fragmentation. Fragmentation also results in the reduction of species richness as species richness is dependent on the extent of the habitat(Rodrigo 2007). The forest of Kaludiyapokuna is fragmented in to small patches by the
land use practices of nearby villagers. Which could be a reason for lowest
species diversity (H’: 3.32) in KP, and also bird species like Zoothera citrina, Rhopocichla atriceps, Pellorneum fuscocapillum were
observed in low numbers in this habitat due to the low extent of the forest
habitat.
Lack of demarcation of boundaries is one of the major reasons for the
increased human activities within the sanctuary. Therefore proper boundaries should be
established and manned to minimize this human encroachment. Although the sanctuary harbours large
number of birds, a proper conservation action plan is not in place and as this
area is also an archeological site it is frequently
subjected to the mining or excavation. There is no adverse effect to the
habitat by tourists who visit the sanctuary in general. But the pressure is intense on the days
of the main festival during the month of June.
Conclusions
The Brown-capped Babbler (Pellorneum fuscocapillum), is
endemic to Sri Lanka, and birds such as this species need to be conserved by
taking steps to reduce habitat fragmentation. Strategies should be developed to
conserve the bird diversity that exists in the forest patches and further
research is needed to help conserve the forest fragments.
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