Biodiversity of the Bharathiar university campus , India : A floristic approach

A total of 335 vascular plant species represented by 222 genera belonging to 67 different families were recorded, of which only one species was represented by gymnosperms. The Poaceae, Fabaceae, Mimosaceae, Caesalpiniaceae and Amaranthaceae were the dominant families of the vascular floristic composition of the study region. The occurrence of invasive alien species is detrimental as they have started invading the campus flora. Though the exotic species should be allowed to grow, introducing and adding new species should be avoided in the campus as they are affecting the survival of the native plant diversity. 
 
   
 
 Key words: Floristic diversity, exotic plants, habitat destruction, Bharathiar University, Tamil Nadu.


INTRODUCTION
Biodiversity is the total variety of life on earth.It includes all genes, species and ecosystems.In short it reflects the totality of genes, species and ecosystems in a region (FES, 2010).The studies of biodiversity have now assumed greater significance as ecologists try seriously to document global biodiversity in the face of unprecedented perturbations, habit loss and extinction rates.
To understand and assess richness of the biodiversity, a taxonomic study of the flora and forests is very much essential.Floristic surveys are the only means by which we can achieve this goal.The floristic studies are considered as the backbone of the assessment of phytodiversity, conservation management and sustainable utilization (Jayanthi and Rajendran, 2013).
The flora are helpful in providing clues of changing floristic patterns, new invasions, current status, rare, endemic and threatened taxa (RET) in a phytogeo-graphical area.They also form a vital component of any resource management and planning activities at the local, regional and global levels.It is essential to prepare local floras of urban areas where there is severe threat to natural vegetation due to identification of species that are in different stages of vulnerability (Padalia et al., 2004) as well as the various factors that influence the existing vegetation in any region (Parthasarathy, 1999).Knowledge of vegetation and flora of any region is essential for the study of its biodiversity and environment.Today there is a pressing need for detailed surveys of plant resources, both exotic and indigenous for the development of rural as well as urban economy of a region.Preparation of the flora of smaller areas like districts, protected areas, unexplored areas, etc. is not only a pre-requisite for the revision of the flora of the vast country like India, but also for understating the ecosystem function and its conservation.Hence, *Corresponding author.E-mail: arajendran222@yahoo.com.floristic studies form a vital component of any natural resource management and planning activities at the local, regional and global levels.
Several studies have been conducted to analyze the floristic composition of the wall habitats in India and abroad (Brandes, 1995;Krigas et al., 1999;Altay et al., 2010;Bilge, 2001;Ocak and Ture, 2001;Ture and Bocuk, 2001;Turgut, 1996;Harshad, 2008).The Bharathiar University campus has rich and diverse ecological communities performing a variety of functions.This diversity has been modified at times and has tried to sustain itself in changing circumstances.Several academicians have found the campus a very informative and practical laboratory to study several floral aspects.However, the drawback is the lack of proper documenttation of the several components of the natural history on the campus.
To understand the significance of the existing biodiversity it is necessary to understand what is valued of the place and what are the benefits it provides and its relevance for the future.Hence, the present study was conducted to examine the vascular plant diversity in the Bharathiar University Campus (Tamil Nadu), India.The outcome of the study can be used constructively in planning sustainability of both man and natural environment.

Study area
The Bharathiar University Campus is situated at the foot hills of Maruthamalai Hiils, at an elevation of 410 m altitude above mean sea level (MSL).With a campus of over 1000 acres, the Bharathiar University is considered as one of the green educational institution in Coimbatore with a rich floral and faunal diversity.The campus is known for its excellence in education, in addition the entire campus has a fairly diverse ecological setting.It is geographically located at 76° 52' 44° 64' longitude and 11° 02' 24° 38' N latitude.The campus is located in habitats of scarce vegetation due to dry weather prevailing in it.According to Champion and Seth (1968), the vegetation of the Maruthamalai hills comes under the dry deciduous thorn forests.

Floristic analysis
This study was carried out between the periods 2008 -2010.Periodical survey was made for the identification and collection of plant species followed by botanical name, family, habitat, uses and anthropogenic disturbances to the natural vegetation in campus.During the course of study, field visits were made to every nook and corner of the University Campus in search of vascular plant species occurring in the region.The plants were freshly collected and their digital photographs were also taken.The collected plant specimens have been identified using taxonomic literatures (Gamble andFischer, 1915-1936;Matthew, 1983;Nair and Henry, 1983;Henry et al., 1987Henry et al., , 1989;;Chandrabose and Nair, 1988).Further, their identification was confirmed by matching with authentic specimens in the Madras Herbarium (MH), Botanical Survey of India, Southern Circle, Coimbatore, India.The voucher specimens were deposited at the Herbarium of Department of Botany, Bharathiar University, Coimbatore for future reference.

RESULTS AND DISCUSSION
On the basis of field survey conducted in the campus area, 335 species belonging to 67 families were collected, identified and listed (Table 1) excluding the lichens, Pteridophytes, bryophytes and mycoflora which was not possible during the present study.Out of the identified plant species, 334 belong to the angiosperms which include 238 species of Dicotyledons and 96 species of Monocotyledons and the remaining one species belong to Gymnosperm (Figure 1).When floral elements were examined based on family, it was determined that Poaceae contained the most species with 72, Fabaceae were represented with 27 species, Mimosaceae were represented with 14 species, Caesalpiniaceae and Amaranthaceae were represented with 12 species each and Acanthaceae represented with 11 species (Figure 2).
The genera represented by the highest number of taxa in the study are as follows: Eragrostis is represented by 11 taxa, Brachiaria by 8 taxa, Cyperus by 7 taxa, Accacia and Ficus by 6 taxa each and Jasminum by 5 taxa.Of the total plant species observed, based on the habit, herbs were represented by 51%, followed by 24% of trees, 13% of shrubs and 12% of climbers (Figure 3).Furthermore, of the 335 species found, 64 species are considered as introduced species to the campus and they were found solely in disturbed areas such as roadsides and early succession fields.However, some are widespread through much of the forests.
A large number of alien species were reported from the campus of Bharathiar