Butterfly diversity in tropical moist deciduous sal forests of Ankua Reserve Forest , Koina Range , Saranda Division , West Singhbhum District , Jharkhand , India

The Sal Shorea robusta forests of the Saranda Forest Division are rich in high and medium grade hematite deposits and many mines are operational in the area for extraction of iron ore. Recently, some new lease areas for iron ore extraction/mining inside sal forest tracts have been proposed and marked for private companies. As such these forest tracts are now threatened with mining and so is their biodiversity. A study was carried out in the sal forests of Ankua Reserve Forest in order to assess the status of fauna. The aim of the present study was to evaluate species diversity of butterflies and to identify species of conservation priority, if any, as there is no previous record of butterflies from West Singhbhum District, Jharkhand. In addition, understanding the biodiversity profile of the area can provide data for better mining practices, mitigation plans, and suggesting biodiversity offsets for the conservation of threatened biodiversity (ten Kate et al. 2004). There are no previous records on butterflies in Saranda Division, West Singhbhum District, Jharkhand (Sinha1962; DFE 2009). Previous butterfly records from Jharkhand State pertain only to Hazaribagh and Ranchi districts (Morrison-Godfrey 1950) where 121 species (134 sub-species) were recorded. These records also included some areas of Manbhum District (a district in the erstwhile British ‘East India’, now known as ‘Purulia District’ in West Bengal). Recently, a checklist of 39 species was published for Dalma Wildlife Sanctuary, Jamshedpur District (Verma 2009). Also, a checklist of 174 species of butterflies is available from the adjoining states of Madhya Pradesh and Chattisgarh (Chandra et al. 2007). Mining activity can be a potential threat to biodiversity in this area. Several studies have suggested that butterflies are key taxa for biodiversity monitoring because they reflected changes in land use patterns (Kunte 1997, 2000; Kunte et al. 1999; Kocker & Williams 2000; Padhye et al. 2006). Butterflies are widely recognized as potentially valuable ecological indicators (Erhardt Date of publication (online): 26 August 2010 Date of publication (print): 26 August 2010 ISSN 0974-7907 (online) | 0974-7893 (print)

1855 ;Brown 1991;Kremen 1992) as they are sensitive to and directly affected by any alteration to their habitats, atmosphere, local weather and climate (Watt et al. 1968;Heath1981;Rosenberg et al. 1986;Dennis 1993).They are highly sensitive to changes in temperature, humidity, and light levels that are typically affected by habitat disturbance (Ehrlich et al. 1972;Blau 1980;Spitzer 1997;Brunzel & Elligsen 1999;Balmer & Erhardt 2000).In addition, butterfly diversity may serve as a surrogate for plant diversity because butterflies are directly dependant on plants, often in highly co-evolved situations (Ehrlich & Raven 1964).

Study area
Ankua-Hatnaburu area (Image 1) of West Singhbhum District, Jharkhand is located about 20km to the south of Manoharpur Town.It is about 60km north-east from the district headquarters, Chaibasa, and lies between 22 0 13'44.34"-22 017'20.50"N& 85 0 14'35.08"-85 017'16.66"E.The highest altitude in the area is 677m and the lowest is 320m.Phyllites form the dominant rock types of the area.The soil colour varies from grey, greenish-grey, brown to reddish-brown.The Koina and the Karo rivers flow northward and, along with a series of NW-SE flowing tributaries, form the region's drainage system, finally joining the Mahanadi River.The area has a humid tropical climate.In summer temperature varies between 40-46 0 C while winter temperatures get as cold as 4 0 C. The area receives maximum rainfall during the South West Monsoon (July -September), which ranges between 1500 and 1700 mm.
-Site-II (near Sukri mines) -Mixed sal forest with small openings and grassy patches, undergrowth thin due to grazing by cattle in some patches.
-Site-III (near Hathnaburu/Dhobil mines) -Sal forest edge close to operational Dobil mines with small-sized trees and openings with thin undergrowth due to grazing -Site-IV (near Sukri-Dhobil road)-Dense, high and mixed sal forest but undergrowth thin due to grazing in some patches.
A two-day reconnaissance survey was carried out during February 2008 to identify the study sites.A random sampling was then conducted as a comprehensive survey was not possible due to time limitations, and restricted movement due to Naxalite insurgent activity in the study area.However, during September 2008, a four-day site specific sampling survey was possible in each of the four sites, but then heavy rains and major landslides restricted the movement through forest roads, reducing the number of working hours in the field.
During the September 2008 survey, a linear transect of 1km each was chosen at each site for sampling.Each transect was trekked for 1.5h to sample butterflies using the standard 'Pollard Walk' methodology.All the species encountered and their relative abundance were recorded daily while trekking along the foot trails.Voucher specimens were collected of some of the species that could not be identified in the field and some species were photographed.Specimens of some species were caught for identification and later released.Temperature during the September sampling period (23-26 September 2008; between 1000 and 1300 hr) varied between 25 and 28 0 C and relative humidity between 85 and 90%.

Statistical Analysis
A. Shannon index -H': Species diversity was calculated using the Shannon Index, which combines the number of species within a site with the relative abundance of each species (Shannon 1948;Magurran 1988, Odum 1997;Krebs 1989).
H' = -Σ pi ln pi Here, pi is the proportion of the ith species in the total sample.The number of species (species richness) in the community and their evenness in abundance (or equitability) are the two parameters that define H'.

B. Pielou's evenness index (equitability) or J':
The species evenness is the relative abundance or proportion of individuals among the species.Evenness of species reveals how their relative abundance is distributed in a particular sample or site (Pielou 1969;Magurran 1988).
J' =H'/ ln S Here, S is the number of species present in the site.The value of J' ranges from 0 to 1.The less variation in communities between the species, the higher the value of J'.
c. Sørensen's Similarity Index: ß = 2c / (S 1 + S 2 ) where, S 1 = the total number of species recorded in the first community, S 2 = the total number of species recorded in the second community, and c = the number of species common to both communities.The Sørensen's index (Sørensen 1948) is a very simple measure of beta diversity, ranging from a value of 0 where there is no species overlap between the communities, to a value of 1 when exactly the same species are found in both communities.

ReSultS
The study revealed the presence of 71 species of butterflies belonging to five families and 56 genera from all four sites during both sampling surveys (Appendix 1).An additional species, Gram Blue, Euchrysops cnejus was recorded in Ankua Reserve Forest but outside the study area.The total number of species recorded was lower during February (38) as compared to September (56).The most common species sampled during the study was the Common Grass Yellow Eurema hecabe (Image 2) which constituted 42.4% followed by Large Oak Blue Arhopala amantes (10.8%) (Image 3), Common Sailer Neptis hylas (3.8%) (Image 4), Chocolate Pansy Precis iphita (3.6%), Grey Count Tanaecia lepidea (2.6%) (Image 5), Common Emigrant Catopsilia crocale (2.2%), Blue Mormon Papilio polymnestor (2.2%) (Image 6), and Common Mormon Papilio polytes (2.2%) of the total butterfly abundance in the study area (Appendix 1).The remaining 63 species had less than 2% abundance, individually, of the total abundance in the study area.Some species showed preference for particular sites.These were the Blue Mormon Papilio polymnestor and Colour Sergeant Athyma nefte (Image 7), which occurred only in sal forest site I with dense undergrowth and canopy, while Staff Sergeant Athyma selenophora (Image 8), Baronet Symphaedra nais (Image 9), Chestnut Rajah Charaxes sp.; Gaudy Baron Euthalia lubentina, and Grey Count Tanaecia lepidea preferred site III located at the sal forest edge.

Species Accumulation curve
During the September 2008 sampling survey the species accumulation curve (Fig. 1) for the four sites sampled individually,over four successive days, increased from first to the fourth sampling though the number of new species added slowly decreased towards the end.However, addition of new species during each sampling in different sites suggested high beta diversity in the area and there was still scope for new species to be added after the last sampling.

Species Diversity and evenness of sites
Species richness i.e. the total number of species encountered, diversity index, and evenness index did not vary much amongst the sites 1, 2 and 4 (Fig. 2).However, Site III had the highest value for all three of these parameters.The high value of the Shannon diversity index was mainly attributed to 'edge effect', as this forest site with an intermediate level of disturbance was located between a dense mixed sal forest and an already active open cast mining site.

Similarity of sites for butterfly species
Sørensen's Similarity index of all the four sites for butterfly species composition during September 2008 had values below 0.3830 (Table 1).The low value of this index is an indicator of high beta diversity in this forest area which suggests that all four sites hold a unique diversity of butterflies.
The Sørensen's similarity index between the two seasons (February and September) studied was 0.5053 which suggests seasonal change in species composition/ diversity of butterflies in the study area.

DIScuSSIon
The present study was the first time that butterflies were evaluated in the sal forests of Saranda Divison, West Singhbhum District, Jharkhand.Results indicate high beta diversity of butterflies in these sal forest habitats.Seventyone species of butterflies were sampled in the study area, however these consist of mostly 'common' and 'generalist' species, as none of the species is threatened globally per the IUCN Red List 2008 and none is of 'rare' occurrence in India but are widely distributed (Wynter-Blyth 1957).Three species -Indigo Flash Rapala varuna, Gaudy Baron Euthalia lubentina, Pea Blue Lampides boeticus, sampled are protected by law as they are listed in the Indian Wildlife (Protection) Act 1972 under Schedule II, part II (Anonymous 2006).A specimen of Charaxes was also observed but it was not possible to either photograph it or capture it.Therefore, it is not possible to state with certainty whether it was Charaxes psaphon or Charaxes bernardus.Further surveys are required to clarify this point, which is of relevance, since the north-west Himalayan subspecies of Charaxes bernardus is listed in Schedule II, Part II of the Indian Wildlife (Protection) Act 1972.
Apart from butterflies, other threatened wildlife recorded in the study area during the present survey were, Asiatic Elephant Elephas maximus (Endangered; Choudhury et al. 2008); Sloth Bear Melursus ursinus (Vulnerable; Garshelis et al. 2008) and Indian Giant Squirrel Ratufa indica (Least Concern; Rajamani et al. 2009 ).Races of two species of birds, Green-billed Malkoha Phaenicophaeus tristis tristis, and Pin-striped Tit Babbler Macronous gularis rubicapilla recorded here are isolated populations lying at the southern most edge of their distribution range in central-west India.Prominent amongst the reptiles  The presence of all these species indicates that these forest tracts are rich and unique habitats that hold animal diversity that is typical of 'undisturbed tropical moist deciduous sal forests'.Open cast mining activity including the laying of roads, construction of several civil structures, diversion of water courses, movement of heavy vehicles, labour, firewood collection, etc. would cause disturbance in these habitats (Image 14).These activities can result in habitat fragmentation, population loss and cause local extinctions that would seriously affect the distribution of forest butterflies and other wildlife in the area.Based on the results of this study it is recommended that longterm conservation of these fragmenting sal forest habitats in Saranda Forest Divison is to ensure the biodiversity which can be achieved through 'good mining practices' and/or creating 'biodiversity offsets'.

Image 1 .
Location of the study areaThe record of two species, the Leopard Lacewing Cethosia cyane (Drury, 1773) and the Restricted Demon Notocrypta curvifascia (C.& R. Felder, 1862) in Ankua Forest Division, West Singhbhum District, are new for Jharkhand State and also for the region as they have not been mentioned in regional checklists(Morrison- Godfrey 1950;Chandra et al. 2007;Verma 2009).