Ecology and conservation of threatened plants in Tapkeshwari Hill ranges in the Kachchh Island, Gujarat, India

The survey was conducted in Tapkeshwari Hill Range (THR) areas, wherever threatened plant species were said to exist, based on secondary information in literature. Thirteen plant species categorized as ‘Threatened’ by the World Conservation Monitoring centre (WCMC 1994) and also listed under various threat categories in the Red Data Book of Indian Plants (Nayar & Sastry 1988) were surveyed in the THR. All the RET plants reported from the study area occupied eight major habitat types. Thorn mixed forests harbored the highest number of individuals (560) of all RET plants, followed by open scrubs (345 individuals), Acacia senegal forests (328) and thorn mixed scrubs (293). Field observations showed that except Helichrysum cutchicum, all the other RET plant species were reported with very low seedlings and regeneration ratio. This paper discusses the status, distribution and threats faced and the conservation implications at border regions of some of the threatened plants of the arid Kachchh district.


IntroductIon
stated that small and isolated populations often suffer from disrupted biological interactions.Nearly 1500 species of higher plants in India are listed as threatened, most of which are angiosperms (Daniels & Jayanthi 1996).These plants have their own ecological role in the ecosystem and therefore, the conservation status of lesser known plant species and isolated populations need to be assessed both within individual populations and at the metapopulation level (Shaw & Burns 1997).There is reported work in the past in Tapkeshwar Hill Range (THR) on threatened species, especially their ecological requirements.This study is intended to highlight the status and distribution of the species in the study area, the ecological characteristics necessary for their survival, and the threats faced by some of the species designated by following the criteria devised by WCMC and IUCN (Nayar & Sastry 1988;WCMC 1994;Bhandari et al. 1996;GES et al. 2002).

MaterIals and Methods
The study area (Tapkeshwari Hill Range -THR) of more than 140km 2 (14,400ha) covering nine villages under two taluks, i.e.Bhuj and Mundra was surveyed (Image 1).THR is the largest unexplored hilly tract in the district.It is close to Bhuj City, the district headquarters (7km) and provides a high diversity of floral species in various vegetation types or habitats like Euphorbia scrubs, Prosopis scrubs, thorn mixed scrubs, open scrubs, thorn mixed forests with Acacia senegal, A. nilotica and Salvadora mixed (Image 2).Considering the high floral diversity and unique vegetation assemblage of this range, it has been suggested that, this tract and adjoining sites may be declared as Ecologically Sensitive Areas (ESA) (Joshi 2002).
The selected hill ranges experience extremes of weather condition and have three seasons, consisting of winter, summer and monsoon-winter (November to February; minimum averaging 10 0 C), summer (March to June; maximum 38.7 0 C) and monsoon (July to September; average 394.7mm in 2007-2009 and for 16.2 days).
The survey was conducted in the study areas wherever rare, endangered and threatened (RET) plant taxa were said to exist, based on information in the literature (Nayar & Sastry 1988;WCMC 1994;GES et al. 2002).In addition, other adjoining areas, which had similar habitat types where the plants were seen during the survey, were also searched.A combination of belt transects with centred quadrates method were used for sampling.Belt transects of 5m width and length extending to the entire width of the patch were laid.Within this belt, species specific search was carried out and once a target species was located, a speciescentred circular plot of 5m radius in the case of shrubs and 1 to 2 m radius in the case of herbs were laid.In case of abundance of plants, belt transects radiating from the edge of the aquatic body in eight directions were laid to assess the number, and the extent of their spread from the main microhabitat was used to record all other parameters as above.

Iucn-ret Plants reports
Thirteen plant species categorized as threatened by the World Conservation Monitoring Centre (WCMC 1994) and also listed under various threat categories in the Red Data Book of Indian Plants (Nayar & Sastry 1988) were surveyed in the THR.In many rare species classifications, including the Red Book listings of the IUCN, two types of rarity-natural and induced-are not always clearly distinguished.Some species that are naturally rare are also ranked as threatened with extinction.While naturally rare species can be more vulnerable to extinction than common ones, rarity in itself is not synonymous with extinction threat.Understanding the difference between natural and induced rarity is important for focusing conservation efforts.

distribution and age structure status
Overall distribution status of RET taxa in the study area: All the RET plants reported from the study area occupied eight major habitat types, of which thorn mixed scrub, open scrub and Acacia senegal forest harbored the highest number (10 in each) of taxa.The second highest number of taxa (9) was recorded from thorn mixed forest and Euphorbia scrub and so on (Table 2).Interestingly, thorns mixed forest harbored the highest number of individuals (560) of all RET plants, followed by open scrub (345 individuals), Acacia senegal forest (328), thorn mixed scrub (293) and so on (Fig. 1).
Figure 1 shows there is no co-relation between the total number of plots (laid down for sampling) and individual count of RET plants in each habitat in the study area.
Age structure status of RET plants in THR: In this title detailed study on the RET plant species reproduction (with different age classes), regeneration, recruitment and adult plants were documented.However, a total of 13 species have been reported as threatened species in the study area.Only four species like Campylanthus ramosissimus, Citrullus colocynthis, Commiphora wightii and Helichrysum cutchicum were recorded under various reproduction classes in the sample area (Table 3).
Quantification of the reproductive stage of annual herbaceous plants is difficult when compared to bushy perennials because of their smaller size and very short life spans.It is further complicated if it has restricted distribution and low abundance.Within the sample area, field observation showed that except Helichrysum cutchicum, all other RET plant species are reported with very low seedlings and regeneration ratio (Table 3) when compared with the adult plants.In addition, low abundance of some RET plant species could be inherent and for others it may be failure of regeneration.

threats faced
The details of the different kinds of threats faced by the RET plants species were also reported with respect to different stresses and the total number of plants affected along with information on each threat.Species-wise natural and anthropogenic threats faced and the individuals affected are given in Table 4. Natural and anthropogenic disturbances can have dramatic consequences for population growth, particularly for small populations of threatened plants (Coates et al. 2006;Tian et al. 2007); a plant species might be naturally rare because its habitat is restricted (de Lange & Norton 2004).Many species at risk of extinction in the United States are declining because of habitat loss and degradation (Hodges & Elder 2008).Selective cutting causes microclimatic changes and decreases the amount of old and dead trees, which may threaten the persistence of many threatened species (Pykala 2007).
In case of Campylanthus ramosissimus, the common and major threat faced was browsing by cattle, goats and sheep; habitat degradation and some individuals  Rao 1983).It is also used as folk medicine and is one of the highly commercially exploited species.Poor techniques associated with tapping of gum resin have lead to its total destruction in its natural habitat (Cooke 1958;Kumar & Bhandari 1994).During this study it was noted that it was facing four types of anthropogenic and two types of natural threats (Table 4).
Dipcadi erythraeum and Ephedra foliata were threatened by habitat degradation and soil erosion in the study area.No threats were observed on Dactyliandra welwitschii, Indigofera caerulea var.monosperma, Pavonia ceratocarpa and Sida tiagii, during the present investigation, but grazing in the area of occurrence of the species could affect these species by trampling and top soil removal by cattle.In-depth studies are required to identify the threats faced by the species.In the case of Ipomoea kotschyana and Tribulus rajasthanensis, no specific threats were noted, but habitat degradation was observed at a few sites.
The subjective rating of threats based on the field observation showed that except Convolvulus stocksii, all other RET plant taxa faced major threat in the form of habitat degradation (anthropogenic stress or threat) (Table 4; Image 3) due to excessive livestock grazing.dIscussIon and conclusIons The phytosociological analysis with ecological information of RET plants revealed that the Campylanthus ramosissimus, Commiphora wightii, Helichrysum cutchicum and Ipomoea kotschyana have abundant populations in the THR.These species require site-specific conservation strategies with the help of the forest department for their long term survival in the study area.
Among the assessed 13 species, five species are reported to be medicinally important in Kachchh (Joshi 2002;Silori et al. 2005;GUIDE 2009).Of these Citrullus colocynthis, Dactyliandra welwitschii, Ephedra foliata and Tribulus rajasthanensis are lightly used, while Commiphora wightii is heavily exploited  It has been reported that a mature C. wightii (Guggal), can produce 250-500 of gum (Atal et al. 1975) and an estimated 300-400 tonnes of Guggal has been sold in Bhuj every year.However, this plant was found to be widely distributed in the study areas as well as in Kachchh.Crude methods of gum extraction from younger plants (Joshi et al. 2004) are likely to affect its abundance in the future.C. wightii is distributed in patches along the study area.This species, being one of the most valuable medicinal plants, needs special attention for its conservation in the wild as well as by promotion through cultivation.Furthermore, this species is endemic to arid and semi-arid regions of the Indian subcontinent (Bole & Pathak 1988;Dixit & Rao 2000;GES et al. 2002) and has been listed under promotional programmes of the National Medicinal Plant Board (NMPB), New Delhi.During surveys certain localities such as the site between Sanatorium (23 0 10'39.5"N& 69 0 38'35.4"E)and Tapkeshwari Mata Temple in Tapkeshwari MPCAs (Medicinal Plants Conservation Areas) were observed with large patches of C. wightii.Likewise, the site between geo-coordinates 23 0 11'43.6"Nand 69 0 25'10.0'E to 23 0 11'37.6"Nand 69 0 24'50.3'Ewithin THR areas has abundant population of this species.These two sites may be identified for regulated harvesting and seed collection for ex situ conservation of this species by Gujarat State Forest Department.
Awareness of the rarity and the conservation significance of the different species should be created among the locals especially the native healers involved in using these medicinally important RET plants in tradi-Image 3. RET plants affected through various threats tional health care system for healing various types of diseases.

Table 3 . Regeneration status of rare, endangered and threatened (RET) plants
for local medicine.