Population studies , habitat assessment and threat categorization of Polygonatum verticillatum ( L . ) Allioni in Kumaun Himalaya

Natural populations of Polygonatum verticillatum in Kumaun Himalaya were surveyed for population studies, habitat assessment and threat status. This research reveals density of individuals and area occupied were low as compared to other species of the region, indicating habitat loss and heavy exploitation. Status was determined on a site-to-site basis for the entire Kumaun region. Based on species occurrence in selected areas, the species were identified as critically endangered to endangered in different areas. Frequency of P. verticillatum ranged between 50 and 80% at different population sites. Distribution of the species was between 50 and 80% indicating contiguous distributional range at most of the sites and random distributional range at Mukteshwer and Gagar. Density of P. verticillatum was highest (4.40 plant m -2 ) in way to Kafani and lowest (2.60 plant m -2 ) in Bhaman gupha. Total basal cover (TBC) was also found highest (0.91 cm 2 m -2 ) in way to Kafani and lowest (0.35 cm 2 m -2 ) in Bhaman gupha. Important value index (IVI) was found highest (51.68) in Munsyari and lowest (28.84) in Khati. Concentration of dominance (Cd) for the region showed a slight variation, with a range between 0.30 and 0.10. This may be attributed to the narrow range of distribution, habitat restriction and dominance of some species.


INTRODUCTION
The Indian Himalayan region (IHR) is one of the most astonishing physical features on the surface of the earth.Among global mountain systems, the IHR is well known for its diverse landscapes and aesthetic, cultural and biological values (Samant and Dhar, 1997).This richness accompanied with uniqueness (endemism), sensitivity (rarity) and economic value make the biological resources of the region important from different perspectives (Dhar, 2002).The resources are used by inhabitants for various purposes such as fodder, fuel, timber, medicinal, wild edible, etc. (Samant and Dhar, 1997).
Out of 7000 endemic species of plants found in India, over 3000 grow in the Himalayan region (Chatterjee, 1980).In the last few decades, Himalayan ecosystems faced loss of forest lands due to increasing biotic pressure and exploitation for many valuable medicinal plants, which have been used for time immemorial.These plants have been mentioned in literature (Samant et al., 1997) and folk-lore, yet are no longer found in accessible habitats in large quantities.Many species have become rare in several tracts and are found only in *Corresponding author.E-mail: l_tewari@rediffmail.com.inaccessible hilly areas, while a few others have been listed as endangered species.
Himalayan regions are considered as a primary source for collection of important medicinal plants.Several species including Podophyllum hexandrum, Nardostachys jatamansi, Picrorhiza kurrooa, Aconitum spp., Saussurea ovallata, Saussurea lappa, Rheum spp., Polygonatum cirrhifolium, Polygonatum verticillatum and Angelica spp.from the alpine areas are well known for their medicinal values.In India, 814 plant species have been identified as threatened; of these, over 113 taxa occur in the Indian Himalayas.Many of these medicinally important plant species are restricted to small pockets of habitat and their population size is decreasing at an alarming rate (Nayar and Shastry, 1987, 1988, 1990).Environmental degradation and loss of biodiversity as a result of excessive anthropogenic pressure, particularly in the fragile Himalaya have caused much concern among conservationists in the recent years (Kant, 1989;Saraswat and Thakur, 1998).
Kumaun region of Uttarakhand State lies between the latitudes of 28°-44' and 30°-49'N and longitudes of 78°-45' and 81°-5'E (Joshi et al., 1983) and is a hilly region containing a diverse physiographic, orographic and demographic mosaic.Its uniqueness supports rich biodiversity.A number of medicinal plant species have been reported from the Kumaun Himalaya which are facing a risk of extinction.P. verticillatum is one of these species.This species is widely used in traditional systems of medicine.
P. cirrhifolium (Wall) Royle belongs to the family Liliaceae, and commonly known as Mahameda (English name: Solomon's seal), and is a tall, erect, weak herb with stout, creeping rhizomes and a stem 60 to 120 cm high that is terete and grooved.Leaves occur in whorls of 3 to 6 and are linear to narrowly lanceolate, 6 to 15cm long, with margins enrolled, apex coiled and tendrils like.Flowers are white, tinged purple or green, in short stalked clusters of 2 to 4, and arise from the leaf axils.The perianth is 6-parted and somewhat reflexed (Gaur, 1999).It is found in rare, moist-shady localities of montane forests distributed in Himalaya, H.P. to Khasia hills (Gaur, 1999), specifically in temperate Himalayas at an altitude ranging between 2000 and 3000 m (Anonymous, 2006;Garg, 1996).It is an important ingredient of Astavarga (Singh, 2006); a medicine used for diseases of children, burning sensations, fever, jaundice, bleeding disorders, blood disorders and debility due to chest injuries (Anonymous, 1999(Anonymous, , 2006)).Leaves are eaten as vegetables; roots infused with milk are used as an aphrodisiac and blood purifier; and a paste is used in cuts and wounds (Gaur, 1999).It is also used in Jvara, Raktavikara, Ksaya, Daha, Raktapitta, Balaroga, Kamala, Ksata and Ksina (Anonymous, 2006).It is considered as a main constituent of 'Astavarga', a group of eight drugs, which forms an important base for a number of Ayurvedic preparations.
Keeping in mind the importance of P. verticillatum, this study attempted to determine population status, habitat assessment and threat categorization of this herb in the Kumaun region.

Study area
The study was conducted in temperate regions of Kumaun.Five districts of Kumaun including Almora, Bageshwar, Champawat, Nainital and Pithoragarh were selected for population studies of the four herbs: P. verticillatum, P. hexandrum, N. jatamansi and P. kurrooa as these five districts cover temperate region of Kumaun.The study areas were surveyed extensively and a total 17 sites for P. verticillatum were identified on the basis of (a) habitat attributes (altitude/slope/aspect), (b) population size and (c) accessibility for data collection.A district-wide geographical description of each study area is given in Table 1.

Population studies, habitat assessment and threat categorization
In nature, P. verticillatum sprouts between April and May and reaches senescence by the end of October.Considering this, a phytosociological study was carried out in August-September after all species had attained maximum growth.For population studies, temperate regions of Kumaun were visited at regular intervals during three consecutive years (2007to 2010).Plots of 100 x 100 m were identified and marked on each region of P. verticillatum.Vegetation sampling was conducted through vertical belt transects (Michael, 1990).Since the distribution range is narrow and topography is very diverse, approximately 60 m long and 30 m wide transects were laid across each plot.Transects were divided into three stands of 20 x 10 m size as replicates and ten quadrats of 1 x 1 m size were laid randomly in each stand.Individuals of all species were counted in each quadrat.To determine status of the species, mean values of each quantitative parameter of three stands of transect were considered for further interpretation.
Data were analyzed for the population study as frequency (%F), density (D, plant m -2 ), A/F ratio, relative frequency, relative density, relative dominance and total basal cover (TBC, cm 2 m -2 ) and calculated following Misra (1968): Total number of quadrats in which species occurred Frequency = x 100 Total number of quadrats studied Total number of individuals of a species in all quadrats Density = Total number of quadrats studied Total number of individuals of a species in all quadrats Abundance = Total number of quadrats in which the species occurred Abundance A/F ratio = Frequency Distribution pattern of the species was analyzed on the basis of abundance to frequency (A/F) ratio.Value of A/F < 0.025 was categorized as regular, between 0.026 to 0.050 as random and > Ramgarh, Mukteshwer, Gagar.

Pithoragarh
Located between 29.4° to 30.3° North Latitude and 80° to 81° East Longitude at a height of 1645 msl.
Similarly, relative values of frequency, density and dominance were calculated following the methods of Misra (1968) and Kershaw (1973)  The concentration of dominance (CD) was computed by Simpson's Index (Simpson, 1949).For threat assessment, two criteria, that is, population estimation (density and number of mature individuals) and extent of occurrence (number of populations/plots) were used as per IUCN Red List Categories (IUCN, 1993).During the study, only flowering plants were considered as mature individuals and taken further for population estimation.Species having mature individuals <250 was considered as critically endangered, <2,500 as endangered and <10,000 as vulnerable.Similarly, species having a single population was categorized as critically endangered, <5 populations as endangered and <10 populations as vulnerable.Furthermore, status was assigned separately for each natural site as well as for the entire Kumaun region.

RESULTS
The ) in Bhaman gupha.Important value index (IVI) was found highest (51.68) in Munsyari and lowest (28.84) in Khati.Concentration of dominance (Cd) was highest (0.30) in way to Sunderdhunga and lowest (0.10) in Mukteshwer and Gagar.Distribution pattern (R/F ratio) of the species was found contiguous in all sites except Mukteshwer and Gagar, where distribution was found to be random.As per IUCN Red List Categories, data on extent of occurrence (number of populations/plots) indicated critically endangered status of the species in most of the sites studied except Phurkia, Ramgarh and Mukteshwer, where its status was endangered.Population estimation (density and number of mature individuals) indicated critically endangered status for the species in all the sites studied, and overall status for Kumaun region was found to be vulnerable and endangered (Table 2).
Moist grassy slopes, under canopies of Cedrus deodara  3).District wise phytographs of IVI, relative frequency, relative density and relative dominance of all four species are given in Figure 1.

Population studies
Over exploitation and habitat degradation have been causing decreases in the population of P. verticillatum.
Research reveals that some of the medicinal plants of high therapeutic value are endangered and require protection.In general, endangered and rare species generally show low levels of morphological variations, so it is important to determine population polymorphism at the biochemical and genetic levels to study these variations and develop appropriate conservation strategies.
It is indeed fascinating that two third of the world's population depend upon plant resources for their primary health care needs and a fairly large number of modern drugs have been derived from plant natural products, with many following leads provided by indigenous knowledge system.This has added to the popularity of herbal products as part of new health programs in developed countries, and combined with the traditional demand of third world nations has led to a steady increase in the market for medicinal plants worldwide.
Biodiversity conservation is a global issue, and special attention is being given to the conservation of endangered and threatened species.Most conservation programmes in India started on animal systems, however recently endangered plant species have received considerable attention.The importance of Himalayan medicinal species of endangered or threatened status and an urgent need for their conservation has recently been emphasized by many workers (Khoshoo, 1993;Bhadula et al., 1996).
Frequency of P. verticillatum ranged between 50 and 80% at different population sites.Distribution of the species was between 50 and 80% indicating contiguous distributional range at most of the sites and random distributional range at Mukteshwer and Gagar.Density of P. verticillatum was maximum (4.40 plant m -2 ) in way to Kafani and minimum (2.60 plant m -2 ) in Bhaman gupha.Total basal cover (TBC) was also found maximum (0.91 cm 2 m -2 ) in way to Kafani and minimum (0.35 cm 2 m -2 ) in Bhaman gupha.Important value index (IVI) was found maximum (51.68) in Munsyari and minimum (28.84) at Khati population.Concentration of dominance (Cd) of the region showed a slight variation.It ranged between 0.30 and 0.10.This may be attributed to narrow range of distribution, habitat restriction and dominance of some species.
Low density and relatively low dominance of the species in the present study may be due to specific microhabitat requirements of the species and over exploitation for illegal trade, etc.These factors are responsible for restricted distribution fragmented habitat and low populations of all species.
Low population density across the surveyed populations indicates poor availability of the species in the study area.However, random distribution and higher frequency of occurrence is indicative that the species have potential for better performance in these sites (habitats).
It is observed that the whole plant is used for medicinal properties (Murkherjee, 1953;Kirtikar and Basu, 1984) therefore individuals are uprooted indiscriminately.It is reported that harvesting of the whole plant is more destructive than the harvesting of fruits, seeds or leaves in isolation (Sheldon et al., 1997).Furthermore, the removal of the entire plant before seed maturation ceases the possibilities of development of future regeneration (Sheldon et al., 1997).

Threat categorization
The status of P. verticillatum was found critically endangered and endangered in all the sites studied (Figure 2).The principal reason for species endangerment in Himalayan medicinal plants is human interference in natural ecosystems, resulting in habitat destruction and a loss of other natural and biological factors.The use of wild plant resources and subsequent ecosystem alteration often leads to habitat fragmentation.Species susceptible to slack habitats are more fragile and have more difficulty in sustaining populations (especially small and narrowly distributed ones) and consequently this often leads to species endangerment.Habitat loss and degradation have been identified as the major factors, threatening 91% of plant species globally (IUCN, 2000).In the 2000 IUCN Red List, India is ranked sixth for having the highest number of threatened plant species.
An area-specific threat categorization of species is very important for short-or long-term management planning.Various studies have been carried out to explore and identify the threatened plants of IHR (Pangtey and Samant, 1988;Samant et al., 1993Samant et al., , 1996aSamant et al., , b, 1998aSamant et al., , b, 2000a;;Pandey and Well, 1997;Kala et al., 1998).

Conclusions
If over-exploitation and habitat degradation of P. verticillatum continues, it may disappear from these areas within a few years.The patchy occurrence of critically endangered, endangered and vulnerable medicinal plants indicates that high anthropogenic pressure, overexploitation, habitat degradation, habitat fragmentation and lack of awareness among inhabitants are the main causes of declining population of the species.Population assessment of the species using standard ecological methods and recognition of key areas as medicinal plants conservation areas (MPCAs) for in situ conservation, including involvement of the Forest Department and tribal communities are suggested.Mass reproduction using conventional (vegetative and seeds) methods, establishment and maintenance of herbal gardens and medicinal plant nurseries for ex situ conservation, ensuring the availability of quality planting material for cultivation, and education and awareness programs for large-scale cultivation are also suggested.
The data from this study concerning population status, habitat preferences, and threat categorization for P. verticillatum may assist in understanding the ecology of the species and can be used in the development of a conservation plan.The study also recommends the collection of plant material in the senescence phase, which ultimately leads to sustainable utilization of the species (TBC) = Mean basal cover  Density Importance Value Index (IVI) = relative frequency + relative density + relative dominance.

Table 1 .
Districts wise studied sites

Table 2 .
Population Status and Assignment of Threat Categories of Polygonatum verticillatum in Kumaun Himalaya Quercus leucotrichophora trees are the major habitats of P. verticillatum.In some places, it is also found under the canopies of Myrica esculenta and Rhododendron arboreumn with Quercus leucotrichophora and Cedrus deodara.Dominant associates of P.
*Based on extent of occurrence; **based on population estimation; and

Table 3 .
Site characteristics of selected sites of P. verticillatum.