CONTENTS-
Abstract
Introduction
Material and Methods
Results and Discussion
Acknowledgements
References

Recovery and restoration of critically endangered plant species entails understanding its autecology, population genetic structure and creation of new self-sustaining populations in the type habitats. Although a large number of plant species of the Western Ghats are critically endangered, little is known about their autecological details, which severely handicap the conservation efforts. In this paper we report on an effort to initiate recovery of a recently described, critically endangered tree species of the fresh-water swamps viz ., Semecarpus kathalekanensis . Several distinct biological features, viz ., high habitat specificity, consistently small population sizes, dioecious breeding system, skewed sex-ratio and recalcitrant nature of the seeds complicate the recovery of S. kathalekanensis . Further, because of restricted gene exchange among the breeding individuals, the populations are suffering from huge heterozygote deficiency. The human induced habitat destruction has further pushed this species into a stratum below the level of criticality. In order to restore the populations, laboratory-grown seedlings were reintroduced into two type localities, as a pilot study, and monitored for two years. S. kathalekanensis responds favourably to artificial transplanting in its typical habitat. Species was successfully established in new localities. We discuss the structure of recovery plans for such critically endangered plant species of the Western Ghats in the light of the present study.

"…to feel no surprise at the rarity of a species, and yet to marvel greatly when the species ceases to exist, is much the same as to feel no surprise at sickness, but, when the sick man dies to wonder and to suspect that he died by some deed of violence…"

-----Charles Robert Darwin, The Origin of Species

Semecarpus kathalekanensis is a recently described (Dasappa and Swaminath, 2000), critically endangered, evergreen tree occurring in the freshwater Myristica swamps of the central Western Ghats (Raghu, 2000). There are only four known populations of S. kathalekanensis , which have very few individuals with unbalanced age structures- typical of a critically endangered species (Raghu et al., 2001). Small population sizes of rare and threatened species can have consequences that could lead to rapid extinction from such as complete failure of pollinators, or a small population of a dioecious species consisting completely of one gender.   Small populations might lose a large amount of genetic variability due to genetic drift jeopardizing the very survival of the species.

Myristica swamps -the unique fresh-water littoral evergreen forests of the Western Ghats, that once formed an extensive network along the streams of Western Ghats, are now reduced to highly fragmented pockets (Chandran and Mesta, 2001). A large number of these swamps are also being converted into areca-nut gardens (Chandran et al ., 1999). This human induced habitat destruction has greatly reduced the populations of S. kathalekanensis . To increase the population size above the critical level, restoration of this species has been attempted. The Forest Department has declared one of the sites as an in situ conservation spot (Dasappa and Jagathram, 2000). However, there is still a great need to effectively check all human interference and   the invasive weeds to these populations.

A further possible step in the recovery of a species is to introduce propagules into sites where the species is likely to survive and/or to replenish existing populations. Such recovery plans for endangered plants often call for the creation of new, self-sustaining populations within historic range and characteristic habitat (Vasudeva et al ., 2001). Reintroduction can also be done into an existing wild population to boost their numbers and/or genetic diversity   (Uma Shaanker and Ganeshaiah, 1997) or to an area where species can potentially survive. Thus species reintroduction would act as a functional bridge between ex situ and in situ conservation methods (Frankel et al ., 1995). In India, reintroduction of rare plant species is restricted to a few orchid species. Paphiopedium druryii , an awesome slipper orchid was multiplied through tissue culture and reintroduced to type localities in Agasthiamalai hill ranges of south Western Ghats (Tewari, 1995). However, there are no reports of the success of these programmes. Hence, creating new, self-sustaining populations of threatened plant species still remains a great challenge.

With this background, we have initiated a pilot recovery plan for S . kathalekanensis through re-introduction of nursery grown seedlings in to type localities within the central Western Ghats. This involved understanding it's breeding system, assessing genetic structure, working out demographic details, and studying the response of the species for reintroduction. The fate of S. kathalekanensis could represent that of a large number of rare plant species distributed in small fragmented patches in the Western Ghats.   The lessons drawn in conserving this critically endangered species could well form the foundation for addressing the conservation concerns of scores of other threatened species in the Western Ghats.

The study was carried out in the Siddapura range of Uttara Kannada district, Karnataka in the central Western Ghats. The site has a warm tropical climate with an annual rainfall of about 2,500 mm between June and November. Four focal populations were identified within a   25 sq km range near Jog water falls (Table 1). The vegetation varies from evergreen to semi-evergreen forests with unique endemic plants species like Arenga wightii, Dipterocarpus indicus, Pinanga dicksonii, Polyalthia fragrans, Myristica fatua var . magnifica and Gymnacranthera canarica ( Ramesh et al. , 1997) .   The breeding system of the species was studied by observing the tagged individuals during the blooming period.   Seed germination tests were conducted in the laboratory to examine the seed viability and seedling fitness. Six enzyme systems encoded by six putative gene loci (Phospho-gluco mutase (PGM), Phospho-gluco isomerase (PGI ) , Phospho-gluco dehydrogenase (PGDH), Malate dehydrogenase (MDH), Isocitrate dehydrogenase (IDH) and Maleic enzyme (ME)) were resolved to assess the genetic structure and breeding system. The genomic DNA collected from leaf samples of all breeding individuals were subjected to PCR based RAPD using 10 primers and genetic parameters were calculated (Suraj, 2001). After surveying the suitable type localities in Siddapura Range, reintroduction of one-year-old laboratory grown, tagged seedlings were taken-up in two remote but accessible sites during January 2000. At site 1 (14 ° 16' N; 74 ° 46' E; Western aspect), 22 seedlings and at site 2 (14 ° 16' N; 74 ° 45' E; Eastern aspect), 15 seedlings were transplanted near a water-course. We estimated the survival per cent, increment in collar girth, height and number of leaves of these introduced plants after six months as well as after 24 months of transplantation.

Table 1. Location, latitude, longitude and size of different populations of S. kathalekanensis

Breeding System

S. kathalekanensis is a trioecious tree species consisting of male, female as well as, monoecious individuals; however monoecious individuals were rare.   The sex ratio of matured and flowering individuals   (defined as number of male individuals per female) varied among populations studied. It was female biased in Kathlekan -I and in Mundgeteggu populations (M/F = 0.41 and 0.6, respectively), where as in   Kathlekan -II, the sex ratio was 1.38 hence male biased. However, if monoecious individuals were considered as functionally males, the sex ratio raised to 1.75;the overall sex ratio for the pooled data was 0.88 ( i.e . nearly 1:1).

Population Structure and Recruitment

The four populations of S. kathalekanensis have very few individuals with unbalanced age structures typical of a critically endangered species. Although S. kathalekanensis successfully germinates (over 80 %), populations have restricted age classes. The seeds of S. kathalekanesis have a very short viability period (less than one week) because of their recalcitrant nature. On an average, only 40 per cent of the germinated seedlings successfully became young recruits, with a large proportion of germinating seeds and young recruits predated. Generally, in an evergreen forest, there should be many more young individuals than mature trees for any given species. The number in a class is usually twice that in the next larger class, although the ratio increases slightly from each class to the next higher one. In this respect, recruitment in the recent past among the population of S. kathalekanensis seem to be less as evident by less number of individuals belonging to the GBH class 11-50 cm (20.75 %) than those belonging to 51-100 cm GBH class (37.74 %).

Genetic Structure of the Populations

Leaf samples from 34 adult, flowering individuals of two neighbouring populations at Kathlekan swamp (Kathlekan I and Kathlekan II) were subjected to starch-gel electrophoresis.   A total of 6 enzymes, which showed clear and good stainability, were selected after screening for about 20 enzymes. Variation in allele frequency was observed in only four loci namely PGI, PGM1, PGM2 and PGDH2. The overall-mean allele number per loci was 1.44 with 44% polymorphic loci. The Shannon's information index, a measure of genetic heterogeneity, based on all loci was 0.204 ± 0.27; it was 0.55 ± 0.11 based only on polymorphic loci. The observed mean heterozygosity (H o ) of the populations was extremely low at 0.095 compared to the expected heterozygosity (H e ) based on Hardy-Weinberg equilibrium (0.134). This strongly suggests that the populations are suffering from heterozygote deficiency, which could be attributed to severe genetic bottleneck and genetic drift. Rare-relict nature and severe anthropogenic pressures faced by the species might be responsible for genetic drift, while, lack of mating partners due to incomplete blooming synchrony among male and female trees could result in further inbreeding. Interestingly, bigger matured individuals with GBH (>100 cm) had higher H o (11.11%) than those, which had less than 100 cm GBH (6.67%) indicating that younger generations might possess reduced genetic variation. A PCR based RAPD analysis was carried out on the 34 adult individuals.   The genomic DNA was initially screened using 65 primers.   A total of 10 primers, which showed good amplification were selected. . The polymorphism for RAPD ranged from to 61.84 per cent in Kathalekan I to 71.05 per cent in Kathalekan II. The mean Nei's gene diversity over all populations was 0.437 ± 0.065 which is far below than the expected for a typical dioecious species. The level of genetic differentiation between the two populations was very low as suggested by mean F st value (<1%).

Growth and Mortality of Reintroduced Plants

Among the introduced seedlings, all the 22 seedlings at site 2 and 85.19 per cent at site 1 (n=15) survived after 6 months.   However after 24 months it was noticed that only about 45 per cent of the initially introduced plants survived in both the sites. Although the exact causes of mortality were not always known, it appears that most of the seedling mortality occurred due to anthropogenic interference. The growth parameters of the seedlings introduced at the   two sites are shown in   Table 2. The survived seedlings showed signs of good establishment without any silvicultural supplements.

As evident from the Table 2, the collar diameter of the seedlings increased by 312 and about 279 per cent in site 1 and site 2 respectively. The seedlings in both the sites increased their height by about 149 and 189 per cent in 24-months. It is interesting that the seedlings show higher diameter increment than the height increment. It is generally known that the trees in their early period of establishment show higher height growth than the diameter growth. The opposite trend observed in S. kathalekanensis may be attributed to the need for greater anchorage for the swampy species since they may have to withstand a water flow during the rainy season. The data clearly suggests that S. kathalekanensis can be successfully re-introduced into the new localities. Raising the seedlings under controlled conditions can completely minimize the risk of predation in the wild. However, it remains to be seen whether introduced plants can complete (or allowed to complete) all of its life-history processes at these sites.

Table 2 Growth parameters (mean ± SD) of the re-introduced seedlings of S. kathalekanensis in two sites.

Recovery Plan

Recovery plan for a threatened plant species should address issues on demography and genetic variation with respect to new population. However, there is no ideal and universally acceptable plan that is adaptable for every threatened species because of the myriad life-history traits, variety of ecological and historical reasons of the localities. In fact every attempt to recover a species would be an experiment by itself.   Till date, several hundred species of flowering plants have been reported to be propagated and reintroduced into wild (Heywood, 1995). Pavlik et al . (1993) have succeeded in founding a new population of an endangered heterostylus herb Amsinckia grandiflora within its historic range. In case of Schoenus ferrugineus- the transplanted plants of a rare grass like plant growing in marshy places of England, were established well at least in two sites (Brookes, 1981). Most reintroduction studies elsewhere in the world are   yet in the experimental stage, and evidence on their long-term success is still awaited (Brookes, 1981). We are not aware of any other study in India in which a critically endangered tree has been considered for recovery. Our preliminary results suggest that nursery-grown seedlings of S. kathalekanensis could be successfully introduced to type localities. Hence, re-introduction of plants into type localities could be a very effective strategy in restoring critically endangered plants. The steps of a generalised recovery plan is as follows:

Step   1. Assess the current population status of the species and locate 1-2 focal populations for autecological study.

Step   2. Understand breeding system, seed biology and demographic characteristics of the species to identify susceptible stages in the life-history of the species. This is a crucial phase for species whose life cycle depends on other species such as pollinators and dispersers.

Step    3.   Assess the degree of genetic variation and extent of differentiation among all the existing populations.

Step 4 . Locate suitable sites within the historical range of the species for reintroduction after considering ecological (such as climate, soil, slope, floristic composition, levels of disturbance, etc .)   and logistic (such as land-use history, access, size, ownership, etc .) factors. Initially a large number of 'candidate sites' could be considered through consensus on ecological factors, from which a few sites could be short-listed based on logistic factors.

Step 5 . Run a pilot study for 2-3 years to assess the introduced populations for their survival, potential for growth and long-term survival.

Step 6 . Collect the propagules and raise nursery for large-scale introductions. Since genetic variability in small population of threatened species is often low, it is important to maximise allelic diversity in new populations to ensure evolutionary persistence (Uma Shaanker and Ganeshaiah, 1997).  

Step 7 . Create several founding populations in the identified localities after a careful 'genetic composing', such that allelic diversity of the introduced plants is maximum (Uma Shaanker et al ., 2001). Although minimum viable population size is unknown for most plant species, a general range of 500 to 2000 individuals could be taken as a thumb rule (Mace and Lande, 1991).

Step 8. Monitor and evaluate the success of re-established populations using criteria such as growth to reproductive maturity.

Step 9. Readjust the sites/populations through silvicultural management and/or additional introductions following the concept of 'forest gene banks' (Uma Shaanker et al., 2002).

We thank the Karnataka Forest Department, for the kind co-operation and our graduate students of the Forest Ecology course for their help during fieldwork. Partial support from Ashoka Trust for Research in Ecology and Environment ( ATREE ), Bangalore is greatly acknowledged.

Brookes, B.,S.   1981. The discovery, extermination, translocation and eventual survival of Schoenus ferrugineus in Britain. In : The Biological Aspects of Rare Plant Conservation   (Ed: Synge H.) John Wiley and Sons, New York.

Chandran M. D. S., D.K. Mesta & M. B. Naik 1999. Myristica swamps of Uttara Kannada district. My Forest , 35 (3):   207-222.

Chandran M. D. S. and D. K. Mesta 2001. On the conservation of the Myristica swamps of the Western Ghats. pp. 1-19. In: Forest Genetic Resources: Status, threats and conservation strategies , Ed. Uma Shaanker, R., Ganeshaiah, K.N. and Bawa, K.S. Oxford and IBH Publications, New Delhi.

Dasappa and   M.H. Swaminath 2000. A new species of   Semecarpus (Anacardiaceae) from the Myristica Swamps of Western Ghats of North Kanara, Karnataka, India. Indian Forester , 126 (1): 78-82.

Dasappa and Jagatram 2000. Conservation hotspots of rare, endangered and threatened species in Western Ghats. My Forest 35:201-205.

Frankel, O. T., Brown, A. H. D. & Burdon, J. J. 1995. The Conservation of Plant Biodiversity , Cambridge University Press, pp. 299.

Heywood V. H. 1995, In : Global Biodiversity Assessment. UNEP and Cambridge University Press, Cambridge.

Mace, G.M., and R. Lande 1991, Assessing extinction threats: Toward a re-evaluation of IUCN threatened species categories. Conservation Biology 5: 148-157.

Pavlik B. M., Nickrent, D. L. & Howland, A. M.             1993. The recovery of an endangered plant. I. Creating a new population of Amsinckia grandiflora . Conservation Biology 7: 510-26.

Raghu H.B. 2000. Reproductive biology and conservation of Semecarpus kathalekanensis : a threatened swamp species of the central Western Ghats. Thesis submitted to the Department of Forest Biology, University of Agricultural Sciences, Dharwad, Karnataka, India.

Raghu H.B., Vasudeva, R., Dasappa, Uma Shaanker R. & Ganeshaiah K. N., 2001. Ecology & conservation of Semecarpus kathalekanensis : A critically endangered freshwater swamp tree species of the Western Ghats, India; In: Proceedings of the International conference on Tropical Ecosystems .(Eds) K.N. Ganeshaiah, R. Uma Shaanker and K.S.Bawa. Published by Oxford-IBH, New Delhi. pp. 677-680.

Ramesh B. R., Pascal J. P. & Jauguier C. A., 1997, Atlas of endemics of the Western Ghats (India): Distribution of Tree species in the evergreen and Semi-evergreen forests, Institute Francis de Pondichery, Publication du department d ecologie, 38: 403.

Suraj P. G., 2001. Genetic structure of Semecarpus kathalekanensis : a critically endangered tree species of central Western Ghats. Thesis submitted to Department of Forest Biology, University of Agricultural Sciences, Dharwad, Karnataka, India.

Tewari D.N., 1995. In : Western Ghats Ecosystem. International Book Distributors Dehra Dun.

Uma Shaanker R. & Ganeshaiah K. N., 1997. Mapping genetic diversity of   Phyllanthus emblica : Forest gene banks as a new approach for in situ conservation of genetic resources.   Current Science , 73 ( 3): 163-168.

Uma Shaanker R,. Ganeshaiah K. N., Nageswara Rao, M. and Ravikanth, G. 2001. A new approach to conservation of genetic resources of forest trees: Promise and processes pp. 263-271 In: Forest Genetic Resources: Status, threats and conservation strategies . Ed. Uma Shaanker, R., Ganeshaiah, K.N. and Bawa, K.S. Oxford and IBH Publications, New Delhi.

Uma Shaanker R., Ganeshaiah K. N., Nageswara Rao, M. and Ravikanth, G. 2002. Forest Genebanks: a new approach to conserving forest tree genetic resources. Pp 229-236 In: Managing Plant Genetic Diversity. Ed. Engels, J.M.M., Ramanatha Rao, V., Brown, A.H.D and Jackson, M.T. CABI Publishing, Wallingford, United Kingdom.

Vasudeva R. Raghu, H B., Dasappa, Uma Shaanker, R. & Ganeshaiah, K. N. 2001. Population structure, reproductive biology and conservation of Semecarpus kathalekanensis : A critically endangered freshwater swamp tree species of the Western Ghats. pp 211-223. In: Forest Genetic Resources: Status, threats and conservation strategies . Ed. Uma Shaanker, R., Ganeshaiah, K.N. and Bawa, K.S. Oxford and IBH Publications, New Delhi.

1 Department of Forest Biology, College of Forestry, Sirsi, 581 401, INDIA.

2 Department of Crop Physiology, 3 Department of Genetics and Plant Breeding, University of Agricultural Sciences, GKVK, , Bangalore 560 065, INDIA.

4 Ashoka Trust for Research on Ecology and Environment, # 659, 5 th A Main Hebbal, Bangalore 560 065, INDIA

5 Jawaharalal Nehru Center for Advanced Scientific Research, Jakkur, Bangalore 560 065, INDIA.

Ph: 0838 428515

Fax: 428486

E-mail: vasukoppa@yahoo.com