A checklist of the winter bird community in different habitat types of Rosekandy Tea Estate of Assam, India
Aftab Ahmed 1 & Mithra Dey 2
1,2 Department of Ecology and Environmental
Science, Assam University, Silchar, Assam 788011,
India
1 aftabahmed372002@yahoo.co.in, 2 mithradey@gmail.com
(corresponding author)
Abstract: This study was aimed at preparing an
inventory of the avifauna and to document the species composition of birds
during winter in different habitat types of RosekandyTea Estate of Cachar District of Assam. Four habitat types, viz., tea
plantation, ecotone zone, secondary growth forest and
water bodies were selected within the tea estate and surveyed from mid-December
2010 (early winter) to mid-April 2011 (late winter) covering four months of
survey. A total of 88 species were
recorded during the survey period with the highest number of species in ecotone zone (n=63), followed by secondary forest (n=60),
tea plantation (n=48) and water bodies (n=17). The species were further categorized
into different feeding and habitat guilds to study the distribution of bird
species in different habitat types according to various guilds.
Keyword: Avifauna, ecotone,
habitat, secondary growth forest, tea plantation.
doi: http://dx.doi.org/10.11609/JoTT.o3246.5478-84 | ZooBank:urn:lsid:zoobank.org:pub:97FA1B39-32BD-4F6C-9329-FDB3DD4D962C
Editor: Rajiv Kalsi,
M.L.N. College, Yamuna Nagar, Haryana, India. Date
of publication: 26 February 2014 (online & print)
Manuscript details: Ms #
o3246 | Received 04 July 2012 | Final received 12 February 2014 | Finally
accepted 13 February 2014
Citation: Ahmed, A. & M. Dey (2014).A checklist of the
winter bird community in different habitat types of RosekandyTea Estate of Assam, India. Journal of Threatened Taxa6(2): 5478–5484; http://dx.doi.org/10.11609/JoTT.o3246.5478-84
Copyright: © Ahmed & Dey 2014. Creative Commons Attribution 3.0 UnportedLicense. JoTT allows unrestricted use of this
article in any medium, reproduction and distribution by providing adequate
credit to the authors and the source of publication.
Funding: None.
Competing Interest: The
authors declare no competing interests.
Acknowledgements: Authors are thankful to the authorities and staffs of Rosekandy Tea Estate, Cachar,
Assam for their co-operation and help during the study. The authors are
grateful to the Department of Ecology and Environmental Science, AUS. We also
sincerely express our thanks to the Subject Editor and anonymous referees for
their valuable comments on the manuscript.
For image, table -- click here
Habitat destruction in the tropics in the late 20th century
was characterized by high rates of conversion of natural landscapes to
agricultural landscapes (Stotz et al. 1996). Often overlooked, however, is the fact
that the conversion of tropical forests for agricultural use is rarely
complete, and often not permanent. Within the agricultural landscape, one can find a significant amount of
forested area in the form of managed multistoreyagroforestry systems, or agroecosystems, whose
features of structural complexity, microclimate buffering, and diversity of
canopy food plants retain high biodiversity and contribute to the protection of
forest biota (Beer 1987; Alcorn 1990; Perfecto et al. 1996).
In the past decade, a growing number of studies have focused on
biodiversity in shaded agroforestry systems using birds as indicators of
biodiversity (Parrish & Petit 1996; Wunderle& Latta 1996; Greenberg et al. 1997). Bird species diversity in shaded
plantations is nearly always reported to be considerably higher than in other
types of monoculture cultivation (Wunderle & Latta 1996; Petit et al. 1999; Tejeda-Cruz
& Sutherland 2004). Most pieces
of research found shaded plantations to support only a few particular guilds of
the bird population. Generally,
more omnivorous, frugivorous and nectivorous,
but fewer insectivorous species occupy plantations than natural forests (Canaday 1996; Shahabuddin 1997;
Petit et al. 1999); generalist and open-grassland species are abundant in
plantations than forest species (Hughes et al. 2002; Naidoo2004).
As for tea plantations, very little research has been conducted
regarding biodiversity assemblage in the tea gardens. Shaded tea plantations strictly follow
monoculture cultivation of the tea plant supported by very few species of
deciduous shade trees. The
sensitivity of tea plants to water, shade and pest also further complicate the
functioning of the tea gardens and are thus to a large extent dependent on
human intervention. However, tea
plantations accompanied by neighboring patches of
forest and water bodies greatly contribute in maintaining a high diversity of
animal species in the tea gardens. The variety of forest areas, water bodies and other vegetation cover
along with the tea plantation thus forms the actual driving factor for
biodiversity of the tea estates. The ‘hard’ edges of tea plantation, which are formed by abrupt changes
from tea shrubs to other vegetation cover such as forest or agricultural crop may also effect the movement and distribution of
wildlife.
NortheasternIndia supports some of the rarest, least known and
most sought-after birds of the oriental region. The numerous tea estates in northeastern India thus provide a potential habitat to the
diverse bird community of the region. Barak Valley in Assam, which has very few pristine forestland but a
large number of tea estates has an opportunity to sustain its avifaunal
diversity within these tea plantations. A proper management of shade trees, forest patches and water reservoirs
in the tea estates, keeping in view the needs of the bird community as well as
human needs can form an effective strategy to secure the avian diversity of the
region.
Material and Methods
Study site: The Rosekandy Tea Estate is situated at Barjalenga in Cachar District of
Assam. It is geographically located
within 24042’29”–24041’31”N and 92041’52”–92042’39”E
(Image 1). The maximum temperature
in the study area ranged from 23–34.4 0C; minimum temperature
from 11.4–26 0C; and relative humidity from 60.4–96
%. The total area under the tea
estate is about 1702.01ha out of which, 562.80ha is used at present for tea
plantation while the remaining 1309.78ha consists of uncultivated lands,
secondary forest growth and water reservoirs. The different vegetation types and
plantation patterns result in the formation of various microhabitats in the tea
gardens where different species of birds reside according to their habitat
preferences. Therefore, the study
area was classified according to their physiognomic and floristic composition
into four different habitat types:
Tea Plantation (TP): The plantation areas contains tea shrubs (Camelliasinensis) that reaches a height of 0.5–1 m
with uniformly interspaced shade trees which generally consists of species of Albizzia odoratissima, Albizzia lebbec, Deris robusta, Dalbergia sisu, Albizzia chinensis etc. This habitat type has an open canopy and
two storied vegetation structures.
Secondary Growth Forest (SF): The areas that are not cultivated are covered with secondary semi ever-green forest and marsh lands. The prominent species consists of Dysoxylum sp., Saprosma ternatum, Vitex sp.,Vatica lancaefolia, Castanopsis sp., Mesua floribuanda, Pterygota alata, Vatica lancaefolia,Glochidion sp., Knema linifolia, Ficus sp.,Artocarpus chama, Cynometra polyandra, Mangifera indica, Bombax ceiba, Xerospermum glabratum, Macaranga peltata, Litsea monopetala etc. Bamboo patches and reed growth near the edges of the forest are also
common.
Ecotone Zone (EZ): The third habitat type is the ecotone zone between the secondary forest and tea
plantation. This zone is formed at
the areas where the tea plantation abruptly ends and the forest cover
begins. Contrasting to conventionalecotone, this area does not show a gradient in floral
community but displays an abrupt switch from one habitat type to another.
Water Body (WB): The tea estate contains many large water
reservoirs and ponds which store water during the
rainy seasons. This stored water is
used during the dry season to irrigate the tea gardens. These water bodies form an ideal habitat
for aquatic fauna and aquatic birds and hence are selected as the fourth type
of habitat. Along with this, the
natural streams and tea gardens irrigation canals also form other sources of
water bodies.
Methods
The sampling was carried out during the winter months starting
from mid-December 2010 (early winter) to mid-April 2011 (late winter) covering
four months of survey. Birds were
sampled using the line transects method (Buckland et al. 1993) and
identification was done using standard field guides (Grimmettet al. 2001; Ali 2002). Three fixed
transects of 700m in each habitat type were surveyed every 15 days during the
morning hours between 0600–1000 hr. The opportunistic counts during other times of the day are also included
in the checklist. We followed the
nomenclature and taxonomic sequence of Manakadan& Pittie (2001). To explore species composition in terms
of the feeding guilds and habitat guilds, bird species are classified accordingly
to various feeding and habitat categories based on observations and scientific
literature (Grimmett et al. 2001; Ali 2002).
Results
A total of 88 species belonging to 38 families (Table 1) were recorded
in the Rosekandy Tea Estate during the four-month
survey. The highest number of species were recorded in the ecotonezone (n=63), followed by secondary forest (n=60), tea plantation (n=48) and
water bodies (n=17). According to
the various feeding guilds, out of the 88 species, the highest number of species were omnivores (n=32), followed by
insectivores (n=26), phytophage (n=16), piscivores (n=9) and carnivores (n=5). Habitat wise, most of
the species were generalist (n=30) and forest inhabitants (n=24). Aquatic (n=17) and openlandinhabitants (n=17) form the rest of the surveyed population.
Discussion
The Rosekandy tea estate consists of different
habitat types which are capable of sustaining a
diverse population of avifauna. The
study demonstrated a rich diversity by the presence of a total of 88 species
within the different habitat types of the tea estate. A similar study by Deb & Gupta
(2010) recorded a total of 76 species in four different landscape types of Cachar District.
The study presented signifies the potential of tea agroforestry systems
along with their adjoining forest patches in conserving the bird population of
the region. The study shows similar
trends of species richness as studied in other tea plantations (Githiru et al. 2009) and different agroforestry systems
(Greenberg et al. 1997; Tejeda-Cruz & Sutherland
2004) around the world. This study
recorded similar species of birds from the tea plantation as has been observed
in other bird surveys in this area (Deb & Gupta 2010; Devet al. 2010).
The variation in species richness in different habitat types within the
tea estate contrasted with results from previous studies. In this study, species richness was
higher in secondary forest growth as compared to tea plantation while earlier studies
(Deb & Gupta 2010) reported higher species richness in tea plantations than
the adjutant secondary forest. However, the results coincide with studies in most of the coffee
plantation where neighboring forest patches contained
more species than plantation areas (Wunderle & Latta 1996; Greenberg et al. 1997; Petit et al. 1999). The ecotonezone with the highest species richness denoted an edge effect of this zone.
Feeding guilds in all four habitats were largely composed of insectivore
and omnivore species with a small number of phytophagous,
carnivore and piscivore species. Similar studies in coffee (Greenberg et
al. 1997; Tejeda-Cruz & Sutherland 2004) and
cocoa (Reitsma et al. 2001; Harvey et al. 2007)
plantations showed a higher abundance of omnivore species than insectivore
species. However, studies in other
tea plantations revealed a higher proportion of insectivore and less omnivore
guilds as they were able to adapt to different habitat types
and food resources (Githiru et al. 2009).
The habitat guild in the studied site showed a similar pattern with the
studies in other agroforestry systems (Greenberg et al. 1997; Reitsma et al. 2001; Tejeda-Cruz
& Sutherland 2004) which recorded the higher number of generalist
species. Open-habitat species are
more abundant in tea plantation coinciding with studies in cocoa and banana
plantation (Harvey et al. 2007).
Further studies and monitoring of bird populations in different tea
estates can reveal a more complete description of patterns of bird assemblage
and species composition in the tea agroforestry systems and hence contribute to
the conservation effort for birds in tea gardens.
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