Angiosperm diversity of the Great Indian Bustard Wildlife Sanctuary : a semi-arid grassland , Maharashtra , India

The Great Indian Bustard Wildlife sanctuary is a semi-arid grassland ecosystem spread over an area of 1,222 km2 in the Solapur and Ahmednagar districts of Maharashtra, India. It is an abode of the critically endangered bird, the Great Indian Bustard. A total of 436 plants belonging to 259 genera and 67 families are reported in the present study from the sanctuary, including 22 endemic taxa. Grasses form one of the dominant components of the ecosystem and are represented by about 67 species. The sanctuary is facing severe habitat loss and degradation, posing a threat to its biodiversity. This paper provides a comprehensive documentation of the floristic diversity of the sanctuary. Threats and conservation measures are also discussed.


INTRODUCTION
Grasslands are a major component of the world's vegetation, covering about 24% (Shantz 1954).They are considered to be a major potential sink for carbon, as grassland soil stores more carbon compared to forest soil (Dinakaran et al. 2011).Grasslands occur in places where temperature, precipitation and physical factors such as soil and drainage combine to create conditions that are too dry for trees to grow.Grasslands have evolved through grazing, drought and periodic fire, and therefore almost all grasslands are maintained by either one or a combination of these factors.They provide habitats for many different animals, birds, insects and lizards, which depend on each other for survival (Allaby 2006;Nancy et al. 2013).
Despite their widespread occurrence, grasslands are shrinking at an alarming rate globally, and are fast becoming one of the most endangered of ecosystems (IUCN 2014).The rapid decline of natural grasslands is due to several reasons.Traditionally, grasslands and scrub have been considered as "wasteland".They are prime targets for development projects.About 16% of tropical grasslands have been converted for agriculture or urban development.In forming relatively open areas with low-stature vegetation which intercepts high light intensity, grasslands are also vulnerable to invasive species (Wagner 1989).Their structure and function make them one of the most vulnerable of terrestrial ecosystems to global climate change (Schlesinger 1997;Mooney and Hobbs 2000;Lejeune and Seastedt 2001).Grassland studies are therefore of paramount importance and a pre-requisite for conservation and management of wildlife (Rodgers and Sawarkar 1988;Rahmani 1992).
India has an estimated coverage of grasslands and shrub lands that vary from 3.7 percent to as much as 12 percent of the total area (UNDP 2012).Whyte (1957) has classified Indian grasslands into eight types while Champion and Seth (1968) recognized only three broad categories.The Indian Council of Agricultural Research (ICAR) classified them into five categories, namely Sehima-Dichanthium type, Dichanthium-Cenchrus-Lasiurus type, Phragmites-Saccharum-Imperata type, Themeda-Arundinella type and temperate and alpine cover, based on the dominant grass composition (Dabadghao and Shankarnarayan 1973).Based on eco-climatic factors, the Indian grasslands fall under four categories: Himalayan pastures, Terai grasslands, semi-arid grasslands and Shola grasslands.Among these, semi-arid grasslands are found in Western India, Central India and Deccan and are characterized by grassland tracts with patches of thorn forests.
The Bustard Sanctuary comes under the semi-arid grasslands category and is the abode of the Critically Endangered species the Great Indian Bustard [Ardeotis nigriceps (Vigors, 1831)] (Birdlife International 2011).This ostrich-like bird occurs in the semi-arid grasslands and deserts of India.It prefers open landscapes, and in particular grassy plains in arid and semi-arid areas interspersed with scrub and low bushes (Rahmani 2006; Janakiraman and Jalal | Angiosperm diversity of the Great Indian Bustard Wildlife Sanctuary sunflower, turmeric, onion and vegetables such as lady's finger, brinjal, gourds and spinach.Fruits such as grapes and bananas are also cultivated.Plants such as Parkinsonia aculeata, Eucalyptus tereticornis, Acacia auriculiformis, Dodonaea viscosa, Albizia lebbeck, Casuarina equisetifolia, Duranta repens, Gliricidia sepium, Azadirachta indica, etc., are planted near the forest guest houses and along the roadsides.

Data collection
Regular plant exploration tours were undertaken from July 2010 to December 2012.Field trips were organized in different seasons and covered all parts of the study area.In each field trip, the data collected include: habit, habitat, flowering period and local names.Plant samples of all the species were collected from different areas of the sanctuary.The specimens were critically studied for morphological details and for correct identification.Identification was confirmed by consulting standard literature (Cooke 1901;1908;Naik 1979;Sharma et al. 1996;Pradhan and Singh 1999;Singh and Karthikeyan 2000;Singh et al. 2001;Bhagat et al. 2008;Karthikeyan et al. 2009) and through reference against identified herbarium specimens at Botanical Survey of India, Western Munjpara et al. 2012).It is locally known as "Maldhok" in Marathi.Floristic studies in the semi-arid part of Deccan are few when compared to the Western Ghats region of Maharashtra.However, some publications have described areas adjacent to the Bustard Sanctuary (Naik 1979;Pradhan and Singh 1999;Suryavanshi and Bachulkar 2011;Das Das and Singh 2011;Gaikwad et al. 2012;Das Das 2012).No floristic documentation of the Bustard Sanctuary is available to-date, and hence, this study was undertaken with the primary objective of the Botanical Survey of India to explore, inventory and document plant diversity in protected areas of India.

Study area
The Great Indian Bustard Wildlife Sanctuary (GIB-WLS) was declared a sanctuary vide notification No. WLP-1078/72634/FI in 1979 by the Indian Board for Wildlife to protect the critically endangered and endemic bird, the Great Indian Bustard (GIB).It is located in Solapur and Ahmednagar district of Maharashtra and lies between 17°22′17″ to 18°54′42″ N and 074°23′34″ to 076°15′01″ E (Figure 1).The sanctuary is spread over an area of ca.1,222 km 2 .It also includes about 393 villages within its boundary.In general, the terrain of the sanctuary is flat and undulating with an average elevation of 500 to 600 m above mean sea level and covered by a thin mantle of black cotton soil.Apart from black soil, the soil colour varies from reddish brown to coarse grey.The study area comes under the forest types of semi-arid biotope, open scrublands and southern tropical thorn forest (Champion and Seth 1968).The common tree species in this ecosystem are: Acacia nilotica, A. catechu, Capparis decidua, Senna auriculata, Mimosa hamata and Ziziphus mauritiana.The common herbs include Aeschynomene indica, Alysicarpus vaginalis, Biophytum sensitivum, Cleome viscosa, Glossocardia bosvallia, Indigofera cordifolia and Indigofera linifolia.The common grasses are Apluda mutica, Chrysopogon fulvus, Cymbopogon martini, Dichanthium annulatum, Heteropogon contortus, Ischaemum afrum and Setaria pumila.Factors such as poor soil quality, frequent fire and erosion contribute to the lack of regeneration of the main species and deterioration of native vegetation.The area belongs to the rain shadow region and is prone to annual droughts.June to September is the southwest monsoon season.October and November constitute the post-monsoon or retreating monsoon season.The average annual rainfall in the district is between 550 mm to 650 mm.May is the hottest month with mean daily maximum temperature of 39.9°C and the mean daily minimum of 25.1°C.Grasses form one of the dominant components of the ecosystem.Agriculture is the main occupation of the people in this region.The main crops cultivated include rice, jowar, bajra, pulses, cotton, sugarcane, groundnut, Janakiraman and Jalal | Angiosperm diversity of the Great Indian Bustard Wildlife Sanctuary Regional Centre herbarium, Pune (BSI) and Blatter herbarium, Mumbai (BLAT).Web databases such as The Plant List (2013), International Plant Names Index (IPNI 2013), Tropicos, Biodiversity Heritage Library (BHL 2013), Global Biodiversity Information Facility (GBIF 2013) and Kew World Checklist of Selected Plant Families (WCSP 2013) were also consulted for correct nomenclature, author citation and additional information.Author names have been standardised based on Brummitt and Powell (2004).The voucher specimens are deposited at BSI Herbarium Pune, Maharashtra.

RESULTS
Intensive study on the floristic diversity of the Great Indian Bustard Sanctuary resulted in documentation of a total of 436 taxa (Table 1).They belong to 259 genera spread over 67 families.Of these, 317 (73%) taxa belong to dicotyledons and 119 (27%) taxa to monocotyledons (Figure 2).The most dominant families are Poaceae (67 taxa), Fabaceae (41 taxa), Cyperaceae (30 taxa), Asteraceae (29 taxa) and Euphorbiaceae (24 taxa) (Figure 3).Genera such as Cyperus, Euphorbia, Ipomoea, Senna, Acacia and Crotalaria are dominant, possessing greatest species diversity (Figure 4).The flora of the sanctuary is categorized into different life-forms such as trees, shrubs, herbs and climbers in which herbs dominate the flora followed by shrubs and climbers (Figure 5).Trees are poorly represented with only 30 taxa, most of which belong to the genus Acacia which is

DISCUSSION
In India, less than one percent of grasslands come under the protected area network, of which 0.24% lies in the semi-arid zone.Some of the protected areas of arid and semi-arid grasslands serve as an important genetic resource in the form of grass and shrub species which are vital for maintaining ecological balance and for food security of the country.These protected areas therefore should not only be considered as key for wildlife conservation, but also as gene banks given that modern cereals have originated from wild grasses (Government of India 2006).
The GIBWLS, which is a grassland ecosystem that accounts for 67 wild grass species and 41 wild legumes, is facing rapid industrialization, conversion of grassland to farmlands and an increase in human population Continued during the last 30 years.There are also several microindustries, stone and brick quarries and sugar cane factories located or emerging around the sanctuary's periphery.The cumulative impact of all these land-use pressures has lead to severe degradation of habitat, which in turn is leading to a decline in the population of Great Indian Bustard (Dutta et al. 2011).The remaining suitable habitat consists of small and scattered grassland patches protected under the Drought Prone Areas Programme plots, which was introduced by the Central Government.The total aggregate area of these scattered patches is not more than 400 km 2 , with the biggest patch located in the village called Nannaj that lies to the north of Solapur town.
Plantations of trees such as Gliricidia, Azadirachta, Eucalyptus and Acacia auriculiformis in the grasslands will adversely affect the habitat's suitability for birds and animals and hence they should be removed.The spread of obnoxious invasive weeds such as Hyptis suaveolens, Parthenium hysterophorus, Lantana camara and Cassia uniflora should be controlled and they should be removed from the grassland.Prioritising conservation measures at potential areas such as Nannaj, Mardi, Akolekati, Karamba, Gangevadi, Chapadgaon, Rehkuri and Korti is essential, as these areas harbour several endemic species as well as forming habitat for Ceropegia bulbosa; a relatively rare species in the sanctuary.
Furthermore, GIS studies should be undertaken for mapping the area to identify the potential grassland patches and level of disturbances in the landscape so as to plan for suitable habitat restoration programmes.Considering this scenario of habitat loss and degradation, In this programme, a task force is constituted to prepare an action plan to conserve bustards and their habitats.
Hence, this documentation study is important in providing the floristic diversity of the bustard habitat, to continue habitat specific conservation measures.

Figure 1 .
Figure 1.Map showing the study area.

Figure 6 .Figure 7 .Figure 8 .FF
Figure 6.View of different habitats in Great Indian Bustard Wildlife sanctuary.A: View of core area at Nannaj.B: Clumps of grass dominated by Cymbopogon spp.C: Population of Cyanotis fasciculata amidst grasses.D: Seasonal lake inside the sanctuary showing scrub vegetation.E: View of rocky plateau inside the sanctuary.F: Herd of Black-buck population during monsoon season.

Table 1 .
Janakiraman and Jalal | Angiosperm diversity of the Great Indian Bustard Wildlife Sanctuary List of species in the study area (abbreviations: H= herbs, S= shrubs, C= climbers, T= trees, *= species added based on literature as well as observation in field in vegetative condition.
ContinuedJanakiraman and Jalal | Angiosperm diversity of the Great Indian Bustard Wildlife Sanctuary

Table 1 .
Continued.Janakiraman and Jalal | Angiosperm diversity of the Great Indian Bustard Wildlife Sanctuary Continued

Table 1 .
Continued.Angiosperm diversity of the Great Indian Bustard Wildlife Sanctuary coupled with high probability of extinction of bustards in the near future, the Ministry of Environment and Forests (MoEF), Government of India, has included the Great Indian Bustard under the Species recovery component of the Centrally Sponsored Scheme -Integrated Development of Wildlife Habitats (CSS-IDWH).