SPECIES DIVERSITY, UTILIZATION AND CONSERVATION IN HOME GARDENS OF SOME RESIDENTIAL AREAS, COIMBATORE, INDIA.

The present study was aimed at documenting species composition, utilization and conservation of plant species growing in home gardens of 10 residential areas of Coimbatore city, India. Household interviews and home garden surveys revealed that all the 109 plant species included in 60 families included have some economic uses or with ornamental significance. Higher number of species was herbs followed by shrubs, trees, climbers, succulent herbs, vines and sub-shrubs. The families viz., Asteraceae, Apocynaceae and Acanthaceae contributed higher number of plant species than the other families to the home gardens. The species namely, Celosia cristata, Chrysanthemum odoratum and Ocimum basilicum have registered 50% frequency among the home gardens sampled which indicates that these species have distributed and maintained in comparatively higher number of home gardens. The home garden species are mainly under the categories of vegetables, fruits, ornamentals, economic important species and medicinal. These results further report revealed that homegardens satisfy various household needs like food, ornamentals, medicines, building material, religious and ceremonial uses.


INTRODUCTION
Home garden is generally accepted to be economically efficient, ecologically sound and biologically sustainable agroforestry system (Fernandez and Nair, 1986). It also serves as sink of carbon, thereby, playing an ecological role in the current global climate change scenario (Saha et al., 2009). Home garden maintained in many places not only to meet out the need of day to day life but also to provide ecological security to some extent. Seasonal gardens in many residential areas of developing countries offer adequate economical return to the people (Eliotcoleman, 2000). Home gardens have recently been recognized for their potential for biodiversity conservation (Raheem et al., 2008;Kabir and Webb, 2008) and for their social and cultural significance (Buchmann, 2009;Rowe, 2009). Increasing attentions have been focused on the potential of home garden to harbor genetic diversity, which is a key component of conservation efforts associated with population management (Hollingsworth et al., 2005;Lengkeek et al., 2006;Miller and Schaal, 2006).
Coimbatore is the leading industrial city in southern India, endowed with huge human population of 3,458,045. The industrial areas, educational institutions and residential areas are maintaining home gardens almost in all parts of the city. In addition to several industries like textile mills, boundaries etc. residential areas are well designed in terms of maintaining home gardens and according to availability of the land area, the residents developed and established home gardens. People of upper economic and educated maintained their home gardens mainly with many ornamental plants and some plants of red listed categories also. Despite the well establishment of home gardens no taxonomical and ecological studies have been made so far in Coimbatore city. To address this lacuna, the present study was aimed to document the flora of the home garden and to categorize the plants into medicinal/other economical important species at different locations in Coimbatore city.

Study site
enumerated. The degree of distribution of various plant species among the home gardens was determined as per the following formula:

Number of home gardens in which the species present
In addition to higher species diversity, the diversity of families was noted to be most noteworthy (Table 2). A total number of 60 families with the contribution 109 species were present in Frequency (%) = Total number of home gardens sampled X 100 the home gardens. The family, Asteraceae contributed the higher number of 7 species

Species usage patterns in home gardens
The medicinal and other economic uses of the plant species present in the home gardens of sampling places were documented on the basis of personal interview with the respective gardeners and the owners of the residential homes and by literature. The red listed and endemic species were enlisted according to Ahmedullah and Nair (1987).

RESULTS AND DISCUSSION
For the present study, all over the city of Coimbatore, 10 home gardens in 10 different residential areas have been selected to enumerate the species taxonomically and to evaluate ecologically (Table 1 and Fig. 1). The sizes of the home gardens sampled were also varied much between ca. 25 m 2 and 225 m 2 . The species richness noted to be varied between the home gardens studied. The number of species was not in accordance with the size of the home gardens studied in Coimbatore city. Studies of home gardens in Mexico (Rico Gray et al., 1991) and Indonesia (Abdoella, 2006) indicated that the number of species or individuals is not related to home garden size.
The higher species richness of 32 was present in the home gardens of Ganapathy followed by 30 in Cheran Nagar and Vinayagapuram residential areas each. On the other hand, the lower species richness of 3 was noted in the residential area of Vadavalli. Altogether, 109 plant species belongs to different life-forms were noted to be present in the studied home gardens. Kumar and Nair (2004) aptly regarded home gardens with high species richness above 20 'as the glorious examples of species diversity in cultivated and managed plant communities.
The variation in life-form among the species noted in the home garden of Coimbatore city was mostly herbs (49.54%) followed by shrubs (22.02%), trees (18.35%), climbers (3.67%), succulent herbs, vines and sub-shrub species (1.83%). This may be due to the need and individual option. The most grown herbs in the gardens are mainly for the purpose of supplying of requirements to their day to day life as vegetables, greens and medicinal plants.
(11.67%) followed by the family, Apocynaceae with 6 species (10%), Acanthaceae with 5 species (8.33%), Moraceae, Solanaceae and Fabaceae with 4 species each (6.67%) and Araceae, Amaranthaceae, Myrtaceae, Asparagaceae, Rubiaceae and Malvaceae with 3 species each (5%) to the communities of home gardens. The remaining families have contributed 1 or 2 species only to home garden communities. The higher number of species in the families of Asteraceae, Apocynaceae and Acanthaceae indicates the diverse utility of the plant resources particularly the preferences towards medicinal uses. The present findings of 109 plant species belong to various life-form categories with different utilities indicate the biological richness of home gardens in Coimbatore city (Kumar et al., 1994). The high floristic diversity is perhaps the reflection of the potential of home gardens to serve as repositories of genetic diversity as well. Kabir and Webb (2008) also reported the predominance of herbs and trees in the home gardens of southwestern Bangladesh.
The degree of distribution of the various enumerated plant species was very low and it was ranging between 10 and 50% only ( Table 1). The species namely, Celosia cristata, Chrysanthemum odoratum and Ocimum basilicum have registered 50% frequency which indicates that these species have distributed comparatively in higher number of home gardens (Fig. 2). The other species have recorded below 50% frequency only and hence they have restricted in distribution in few home gardens only. The overall distribution level indicates that each home garden owner has their own preference over the species. Pandey et al. (2006) also reported the lower distribution level of many home garden plants in South Andaman and he explained that the selective cultivation of species with the home gardens is mainly due to the utility value of the species.
The total number of individuals maintained for the constituent species in the home gardens was widely varied (Table 1  represented by only one individual in very less number (Fig. 4). It has been recognized that most of the mentioned above are economically important. The maintenance of this species with higher standing crop individuals in the home gardens may be due to economic security provided by these species to the respective home.

Capsicum annuum Solanaceae Fruit
The root decoction is used for the treatment of fever, dropsy, and dyspepsia. Seed juice is used to relieve ear aches. It is used as carminative, an appetizer and a stomachic. Externally, it is used as a counter irritant and also in the treatment of rheumatism, lumbago and neuralgia. Among the 109 species enlisted in the studied home gardens, the economic importance including the medicinal uses of the various plant species present in the sampled home gardens is depicted in Table 2. In the account of 109 species, 86 (78.90%) were recognized as medicinally important and 23 (21.10%) as ornamentals. The medicinal uses of the plant species are multidimensional. A greater number of 20 species are used to treat skin diseases and a sizeable number of 12 species are precribed for anticancer activities. In addition, 11 species have been known for antidiabetic properties and 2 species each for gynecological disorders and for the treatment of dysentery respectively. Interestingly it has been noted that the 2 species namely Tecoma grandis and Mangifera indica are having antiviral property suggested for AIDS patients. The results of present study exhibited a considerable array of plant species in the home gardens of Coimbatore city with different medicinal and other economic uses. Presently many home gardens show a shift from subsistence oriented agriculture to market (Peyre et al., 2006).

CONCLUSION
In conclusion, home gardens in Coimbatore city appear to be supplementary agricultural production systems, which are managed and controlled by household members. Involvement of family members in home gardening activities empowers them to become self-reliant and simultaneously making a contribution to household food security. In addition, the home gardens can save species from the risk of extinction and thus, home gardens can be considered as a tool for conservation of medicinal plants.

ACKNOWLEDGEMENT
The authors graciously acknowledge Dr.M. Aruchami Research Foundation for providing financial support to carry out this work.