Biodiversity plays a key role in the livelihoods of tribes and other people to meet their needs in day-to-day life. The plant kingdom is directly connected with human beings from the beginning of its origination in the universe  . India is one of the vast biodiversity-rich countries in the world where the medicinal plants have had traditional importance for ages, specifically, in the fields of Ayurveda, Siddha, Unani, and homeopathy. Nearly 75% of the remedially important plant species grows in almost wild conditions  . In the Southern part of India, Indian Institute of Technology-Madras (IIT-M) geographically located with Latitude:: 13.04N, Longitude:: 80.17E, Altitude:: 6 - 16 m above mean sea level. The campus spans over an area of 236 ha comprising of three major zones―academic, residential and hostel; each acting as a thriving environment for flora and fauna and a wide variety animals and reptiles. A fourth zone identified as Wilderness Zone has been selected for biodiversity assessment. This zone has the richest biodiversity in the Campus. Each zone approximately holds 60 ha area in an uneven configuration or shape. This wilderness zone vegetation is majorly of Southern Thorn Forest type, dominated by cactus followed by Ficus which has significant cultural value. As per the survey, the campus has 432 species of plants were identified/observed (Figure 1).
2. Materials and Methods
The institute campus area has a wide distribution of medicinal plants which was made as the main objective of the present study. The distribution of these medicinal plants/tree were identified the aid of taxonomists from Dept of Botany, Alagappa university by referring to authentic literature of the regional flora web database developed by the Prakati Wildlife club of IIT-Madras, Chennai and cross verified with “The flowering plants of Madras city and its immediate neighborhood”  . An effective analysis has been performed to identify the available medicinal plants along with their distribution and their medicinal uses.
2.1. Ethano Botanical Survey
The ethno botanical survey was carried out by wild life club volunteers of IIT-Madras, between august and September 2016. This study covered total vegetation of the area with emphasis on the ethno botanical hotspots of IIT-Madras campus.
Figure 1. Percentage habitat wise distribution of overall vegetation.
2.2. Overall Diversity of Vegetation
Thirty-six per cent of the non-cultivated plants species are trees. Excluding cultivated trees such as papaya, lime, sapota, etc., that are rarely found outside gardens and homesteads, 107 species of trees are present on the IIT-M campus. The greater presence of tree species has rendered the vegetation type as a forest.
2.3. Over All Diversity of Medicinal Trees/Herbs
298 species of non-cultivated plants were identified on the campus. The numbers may increase between 350 - 400 species while including the garden plants. 36% of the non-cultivated plants on the campus are trees. However, of the trees only 40% are native. The higher contribution to the diversity of native flora was rose from the grasses (100%), climbers (84%) and herbs (80%). 107 sps., of plants, are non-native. Among these 9 species were invasive. Prosopis juliflora is the most invasive plant on the campus. 50% to 60% of the trees in the wilderness zone were dominated by this species. Both tree and herb specimens were collected and identified using regional flora. The collected plant specimen’s family and species were confirmed with community herbarium, MS Swaminathan Research Foundation, Chennai.
2.4. Calculation of Shannon Index of Species Diversity and Species Richness
The species diversity of medicinal trees and herbs were calculated using Shannon diversity index  . It has a combination of two quantifiable measures like species richness and species accountability. Higher in numbers of a species denotes wide range of diversity, Shannon-Wiener diversity Index is defined and given by the following function: MATLAB program was created to calculate the Shannon index.  .
H = Σ[(pi) × ln(pi)]
Pi = proportion of total samples represented by species i
S = number of species, = species richness,
Hmax = Ln(S) = Maximum diversity possible
E = Evenness = H/Hmax
3. Determination of Conservation Status of Plants and Herbs
The universal conservation status of identified trees and Herbs were determined by IUCN red data list cross verification.
The results on the survey of the plant diversity in the IIT-M campus showed nearly 100 species of flowering plants (both trees and herbs). Among these, 100 genera belonged to 40 families. The most dominant family in the present study was Fabaceae with 18 species (25%). Next to that, Moraceae comprises 7 species (9%), Malvaceae include 6 species (8%). The dominant medicinal herbs are from Acanthaceae, Apocynaceae, Fabaceae and Rubiaceae contain 4 species (12%), and Convolvulaceae, Euphorbiaceae, Phyllanthaceae, and Vitaceae are second dominant with 2 species (4%) each. The overall habitat is dominated by Trees in the campus (36 %). The detailed investigation of family in the present study and their medicinal values in a different area is represented in Figure 2 and Table 1 & Table 2.
Figure 2. Percentage distribution of (a) medicinal trees and (b) herbs.
Table 1. Diversity of trees on campus.
Table 2. Diversity of medicinal plants on campus.
NA: Not yet Assessed; LC: Least Concern; NT: Near Threatened; VE: Vulnerable ; LR: Lower Risk; EN: Endangered; DD: Data Deficient.
Shannon-Wiener diversity index of species richness (H) for the medicinal tree is 4.263 and evenness (E) is 0.972, whereas in medicinal herb species richness (H) was calculated as 3.284 and evenness (E) was 0.975 (Figure 3).
In addition to the floristic study, the present study enumerated the medicinally important plants in the study area which are used to cure different diseases. Totally 107 medicinal tree and herbs were identified in the wide campus. Of which 73% of trees and herbs are not assessed in IUCN red data list (Figure 4).
The primitive societies of India have been dependent on herbal medicines over a long period of time. In fact, all conventional systems of herbal based therapy had their roots and origin in folk medicines or asthma medicines. The knowledge of ethano botany plays a vital role in the primary health care and economy of tribal’s. Increasing populations of our country require the discovery of new herbal drugs to cure both endemic and epidemic diseases without side effects. India has been endowed with rich biodiversity which comprises of nearly 12% of the global plant wealth. Due to over exploitation of forest and urbanization, one-third of the plants are endemic and endangered. In the present study, various families of
Figure 3. Shannon graph diversity of species richness index of Trees and Herbs in the study area.
Figure 4. Conservation status of (identified in IITM campus) Tree species reported for medicinal purposes in India according to IUCN Red List. NA: Not yet Assessed; LC: Least Concern; NT: Near Threatened; VE: Vulnerable; LR: Lower Risk; EN: Endangered; DD: Data Deficient.
flowering plants are identified in the study area (IIT-M campus). Cross verification of identified plants with IUCN Red data book confirmed the IIT-M wide campus is the shelter for nearly threaded (NT), vulnerable (VE) and endangered (ED) species of medicinal trees and herbs.
We would like to express a deep sense of gratitude to Prakrith, Environmental and IIT campus community for his valuable guidance and help. We also extend our thanks to wildlife club awareness team IIT-M online server providers and maintenance authorities for successful completion of this enumeration of plant diversity.
Conflict of Interests
The authors declare no conflict of interest.
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