Conservation status of Hildegardia populifolia (Roxb.) Schott & Endl. (Malvaceae: Sterculioideae: Sterculieae), an endemic of southern peninsular India

Boyina Ravi Prasad Rao ¹, Madha Venkata Suresh Babu ², Araveeti Madhusudhana Reddy ³, S. Sunitha ⁴, A. Narayanaswamy ⁵, G. Lakshminarayana ⁵ & M. Ahmedullah ⁶

^1,2,4,5 Biodiversity Conservation Division, Department of Botany, Sri Krishnadevaraya University, Anantapur, Andhra Pradesh 515003, India

³ Department of Botany, Yogi Vemana University, Kadapa, Andhra Pradesh 516003, India
⁶ Botanic Garden of Indian Republic, Noida, District G.B. Nagar, Uttar Pradesh 201303, India

Email: ¹ rao_rp@rediffmail.com (corresponding author), ² mvs.ced2010@gmail.com, ³ grassced@yahoo.com,

⁴ sunitha_s2011@rediffmail.com, ⁵ m.ahmed@nic.in

Date of publication (online): 26 August 2011

Date of publication (print): 26 August 2011

ISSN 0974-7907 (online) | 0974-7893 (print)

Editor: N.P. Balakrishnan

Manuscript details:

Ms # o2733

Received 20 March 2011

Final received 16 June 2011

Finally accepted 07 July 2011

Citation: Rao, B.R.P., M.V.S. Babu, A.M. Reddy, S. Sunitha, A. Narayanaswamy, G. Lakshminarayana & M. Ahmedullah (2011). Conservation status of Hildegardia populifolia (Roxb.) Schott & Endl. (Malvaceae: Sterculioideae: Sterculieae), an endemic of southern peninsular India. Journal of Threatened Taxa3(8): 2018–2022.

Copyright: © Boyina Ravi Prasad Rao, Madha Venkata Suresh Babu, Araveeti Madhusudhana Reddy, S. Sunitha, A. Narayanaswamy, G. Lakshminarayana & M. Ahmedullah 2011. Creative Commons Attribution 3.0 Unported License. JoTT allows unrestricted use of this article in any medium for non-profit purposes, reproduction and distribution by providing adequate credit to the authors and the source of publication.

Acknowledgements: We thank University Grants Commission (3-49/98 SR II-1998) for financial assistance. We also acknowledge the support received from the Forest Department of Andhra Pradesh, Karnataka and Tamil Nadu during our field visits from time to time.

Abstract: Hildegardia populifolia (Roxb.) Schott & Endl. an endemic tree of southern peninsular India is assessed in terms of the IUCN Red List status. New data from field surveys indicated Vulnerable species categorization for H. populifolia.

Keywords: Hildegardia populifolia, Red List status, Vulnerable.

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Conservation status of a species is an indicator of the likelihood of that species continuing to survive in nature. The International Union for the Conservation of Nature (IUCN) is the world’s main authority on the conservation status of species (Mrosovsky 1997) and the IUCN Red List provides an objective evidence-based system for classifying species in terms of the risk of extinction. Such conservation assessments are useful tools to prioritize species for conservation action and to monitor the change in status of species over time. The IUCN system assesses the threat to a species based on five core criteria: decline in populations over a period that is relevant for the species (based on generation time); the distribution of the species together with factors that may influence ongoing survival within its current distribution; small population size and continuing decline; very small populations or small distribution area; and quantitative assessment of extinction risk (e.g. modeling) (IUCN 2001). Assessments are always done using the best available information, but often only partial information is available for many taxa. Recently, Babu & Rao (2009) and Rao et al. (2009, 2010) provided valuable field data for the current global population status of Cycas beddomei Dyer and categorized it as Endangered. In the present study, we attempt to assess the current population status of Hildegardia populifolia (Roxb.) Schott & Endl., a southern Indian endemic (Ahmedullah & Nayar 1987).

Hildegardia populifolia, a deciduous forest tree species belongs to the family Malvaceae, subfamily Sterculoideae, tribe Sterculieae. The species was earlier known to be represented by a sole surviving population comprising about 20 trees in Kalarayan Hills of Tamil Nadu (Ahmedullah 1990). It is an enigmatic species in that its conservation status has been variously assessed as Critically Endangered (Sarcar & Sarcar 2002), Endangered (Ahmedullah 1990; Walter & Gillet 1998; Rao et al. 2003). Rao et al. (1998) recognized five subpopulations of this Endangered species in Rayalaseema District of Andhra Pradesh. Jadhav et al. (2001) categorized it as Vulnerable. The World Conservation Monitoring Centre (1998) assessed the conservation status of this species as Critically Endangered. After conducting intensive explorations for the past 15 years, our research team located the species in Anantapur, Kadapa and Chittoor districts in southern Andhra Pradesh, Salem Hills in northern Tamil Nadu and a small patch in Karnataka bordering Anantapur District of Andhra Pradesh. The present study focuses on a critical evaluation of the H. populifolia population and revision of the current conservation status based on the latest IUCN Red List Criteria (version 3.1; IUCN 2001).

Materials and Methods

Hildegardia populifolia is a deciduous tree growing up to 20m (Image 1). The plant is recognizable for its pale green bark. Leaves are ovate-cordate, 3–5-lobed and digitately 7-nerved. Flowers are purple, and erect with leathery perianth. Follicles are winged, erect, thinly woody, falcately ovate-reniform and inflated, with 1 or 2 seeds, affixed from base of the follicle and conspicuously wrinkled when dry. The species is locally known as Galibuduga, Pichipoliki, Buddapoliki in Telugu and Malaipuvarasu in Tamil.

The study area cover all the known localities of the species distribution, i.e., southern Anantapur, western Kadapa, and northern Chittoor districts of Andhra Pradesh; Devikunta area in Karnataka and Salem Hills in Tamil Nadu (Fig. 1). The study area was stratified into grids of 6.25×6.25 km using IRS-1C satellite data. The whole study area falls in the hill ranges of southern Eastern Ghats (11⁰52’–14⁰16’N & 77⁰45’–78⁰59’E) with an altitudinal variation of 420–982 m. Preliminary explorations revealed the presence of H. populifolia in 29 grids in the study area comprising 354 grids. Transects of 1000×5 m were laid down in all the 29 grids. This amounts to approximately 0.019% of the total area, an adequate sampling intensity according to Shivaraj et al. (2000). In all the 29 grids, the plants of ≥30cm gbh were counted and considered for the analysis. Wherever the species was found in the grids, geographic coordinates were recorded and the shortest continuous boundary for the species population was been drawn on the grid map.

The assessment is carried out as per the IUCN Red List Categories and Criteria (IUCN 2001). The Extent of Occurrence (EOO) is estimated as a minimum convex polygon containing all the localities of species occurrence. Area of Occupancy (AOO) of the species within the grids is studied taking into account the terrain features with respect to altitude. The population size of the species is estimated by extrapolating the recorded individuals in the individual transect.

Results and Discussion

The overall distribution of the species falls within an area of ca. 228x90 km. A conservative approach would therefore be to consider this as one location, however, since the threats could vary between different populations, it cannot be considered so. Observations in the field indicated that at least 12 locations identified for the species are separated by reasonably unoccupied areas (Fig. 2). In total, 376 individuals of H. populifolia were counted in all the sampled transects of 29 grids (Table 1). It was observed that the species was found mostly above 420m, restricted to top hills and rock boulders, growing in sandy red soil. Taking these observations into consideration, a grid map has been prepared for measuring the EOO of the species. The EOO is calculated as 14,160km²(Fig. 2). The species has a patchy distribution within the grids and substantial areas in the individual grids (more than 95% area) do not have this species (Fig. 2). The AOO thus is calculated to about 14.6km² (1460ha). The population size of the species is estimated to comprise 23,100 individuals. Results pertaining to the AOO and the number of individuals recorded in transects extrapolation for the whole estimated population is presented in Table 1.

Applying IUCN criteria

Criterion A: The available data does not provide any indicators of change in population size over time and hence this criterion is not applied to H. populifolia.

Criterion B:

Criterion B1: The EOO of H. populifolia is estimated to be 14,160km² and considered to occur at more than 10 locations (sub-criterion a). Further, there are no extreme fluctuations observed with respect to any of (i) to (iv). It qualifies only under the sub-criterion (b) for continuing decline in terms of (iii) area, extent and quality of habitat. Hence, it does not qualify for any of the threatened categories under B1.

Criterion B2: The AOO is 14.6km². However, it does not qualify for either (a) and (c). It qualifies only for the sub-criterion (b) for continuing decline in terms of (iii) area, extent and quality of habitat. Hence, it is not threatened under subcriterion B2.

Criterion C: Small population size and decline. The total estimated population of H. populifolia is >23100 mature individuals. Since the number of mature plants exceed the requirements for Vulnerable status (i.e. <10 000), the species is not considered as threatened under this criterion.

Criterion D: Very small or restricted populations. Although the species population comprises a large number of individuals, it is found restricted to < 20km² and is prone to human activities in terms of fire hence qualifying for Vulnerable category under D2.

Criterion E: No demographic modeling has been undertaken for the species and hence this criterion does not apply for the species.

The final assessment for Hildegardia populifolia based on the present study is: VU D2.

Hildegardia populifolia assessed under three threatened categories in different works, is currently categorized as Vulnerable based on primary data from the field. The present study also provides significant data pertaining to its distribution in peninsular India-in the states of Andhra Pradesh (Anantapur, Kadapa and Chittoor districts) Tamil Nadu (Salem Hills) and Karnataka (in areas bordering Anantapur District of Andhra Pradesh).

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