Tree species diversity in the Eastern Ghats of northern Andhra Pradesh, india

 

M. Tarakeswara Naidu 1 & O. Aniel Kumar 2

 

1,2 Department of Botany, Andhra University, Visakhapatnam, Andhra Pradesh 530003, India

1 tarakeswaranaidu@gmail.com (corresponding author), 2 oak.aniel@gmail.com

 

doi: http://dx.doi.org/10.11609/JoTT.o3764.7443-59

 

Editor: Vijayasankar Raman, University of Mississippi, USA. Date of publication: 26 June 2015 (online & print)

 

Manuscript details: Ms # o3764 | Received 10 September 2013 | Final received 30 May 2015 | Finally accepted 03 June 2015

 

Citation: Naidu, M.T. & O.A. Kumar (2015). Tree species diversity in the Eastern Ghats of northern Andhra Pradesh, India. Journal of Threatened Taxa 7(8): 7443–7459; http://dx.doi.org/10.11609/JoTT.o3764.7443-59

 

Copyright: © Naidu & Kumar 2015. Creative Commons Attribution 4.0 International License. JoTT allows unrestricted use of this article in any medium, reproduction and distribution by providing adequate credit to the authors and the source of publication.

 

Funding: Department of Biotechnology (DBT), Government of India, New Delhi

 

Competing interests: The authors declare no competing interests.

 

Author Contribution: OAK involved in the plan of work, conducted field work and compiled the manuscript. MTN did field work, compiled the field observations and results reported in the paper.

 

Author Details: M. Tarakeswara Naidu is former Research Fellow in Botany, Andhra University, Visakhapatnam. He worked on systematics, ecology, diversity of plants in Eastern Ghats region. Prof. O. Aniel Kumar is Head of the department of Botany, Andhra University, Visakhapatnam. His field of research interests includes Molecular Biology, Cytogenetics, Ecology and Systematics.

 

Acknowledgements: We are thankful to the Department of Biotechnology, Government of India for financial support, and to the staff of Andhra Pradesh State Forest Department for their co-operation during the field surveys.

 

 

 

Abstract: The present study was conducted to analyze tree species diversity in the tropical forests of the Eastern Ghats of northern Andhra Pradesh, India. A total of 270 species of trees (≥15cm girth at breast height) pertaining to 177 genera belonging to 55 families were recorded. Among the 270 species, 141 species were observed to be common, 78 were occasional and 51 species were rare in the study area. Fabaceae was the dominant family with 33 species followed by Rubiaceae with 15 species and Malvaceae, Moraceae and Phyllanthaceae with 13 species each. The genera with the highest number of species include Ficus (12 species), Diospyros (8 species), Albizia and Grewia (6 species each), Acacia and Bauhinia (5 species each). Forty-five percent of the species were indigenous. This illustrates the diversity of the tree species in the studied area of the Eastern Ghats and also emphasizes the need for their conservation.

 

Keywords: Andhra Pradesh, Eastern Ghats, India, tree diversity, tropical forests, vegetation.

 

 

Introduction

 

Trees are the most valuable natural resources that have an immense importance both to living organisms and to derive economy to the country. Trees form the major structural and functional basis of tropical forest ecosystems and can serve as robust indicators of changes at the landscape scale (Sandhyarani et al. 2007; Sahu et al. 2012). A tree is a woody plant that reaches a minimum height of at least 3m having a single stem with a definite crown shape (Lawrence 1951). Trees are the largest and long lived static organisms often with an amazing diversity of forms. Trees comprising the forest cover, serve as a substrate for millions of microbes, herbs, shrubs, climbers and diverse fauna. They provide basic needs to humans in the form of oxygen, food, timber, paper, fuel wood and medicine (Premavani et al. 2014). Trees bind the soil, recycle minerals and regulate the course of rain water.

Tropical forests are the most complex of all the terrestrial ecosystems and generate a variety of natural resources help to sustain the livelihood of local communities (Kumar & Bhatt 2006). These forests are rich in medicinal and economically important plants. Tropical forests are disappearing at alarming rates owing to deforestation for extraction of timber, shifting cultivation and collection of non-timber forest products (NTFPs) (Raghubanshi & Tripathi 2009; Pragasan & Parthasarathy 2010). Tropical trees are interesting subjects because of their rich species diversity (α-diversity) (Chittibabu & Parthasarathy 2000). Tropical forests cover 7% of the earth’s land surface, but harbor more than half of the world’s species (Wilson 1988) and are currently disappearing at an overall rate of 0.8-2% per annum (May & Stumpf 2000; Sagar et al. 2003). Forests in the peninsular India are degrading at an alarming rate (Reddy et al. 2007), which is largely associated with anthropogenic activities and economic problems. The Eastern Ghats of India is a broken chain of hills that runs almost parallel to the east coast of India covering four states: viz., Odisha, Andhra Pradesh, Tamil Nadu and Karnataka. The Eastern Ghats is one of the rich biodiversity regions in India, affected by heavy anthropogenic pressures. The present study deals with detailed botanical and ecological aspects and also documents the diversity of forest tree resources in the Eastern Ghats of the northern part of Andhra Pradesh, India.

 

 

Material and Methods

 

Study area

The Eastern Ghats of northern Andhra Pradesh lies between 16015’–19012’N & 80050’–84047’E and runs through five districts, Srikakulam, Vizianagaram, Visakhapatnam, East Godavari and West Godavari (Fig. 1). The highest elevation in the study area measures about 1615m altitude. The hill range consists chiefly of charnokites and kondalites and varied metamorphic rocks; and the main soil types are loamy, black, lateritic and alluvial. Lateritic soils are the common type along the deciduous forests of the area (Subrahmanyam 1982). The temperature ranges from 28–46 0C during summer and 13–27 0C during winter. Maximum rain fall occurs between July and September with 1300mm per annum during the south-west monsoon period and the relative humidity is quite high throughout the year: 70–88 % (Naidu et al. 2014). There are five major forest types in the Eastern Ghats of northern Andhra Pradesh which are tropical semi-evergreen, tropical moist-deciduous, tropical dry-deciduous, tropical thorny-scrub vegetation and tropical dry-evergreen forest types (Champion & Seth 1968).

 

 

 

 

Data collection

The present study was conducted from 2006–2010. The entire stretch of the Eastern Ghats of northern Andhra Pradesh (650km) was divided on the map into 6.25×6.25 km grids. A total of 210 grids were obtained in the five districts of northern Andhra Pradesh. In each grid, all the living trees of ≥15cm girth at breast height (gbh) were enumerated from a 5×1000 m belt transect of 0.5ha area. Depending on the shape of the forest stand, these transects were divided into 5×200 m sub-transects and data were collected. Voucher specimens were collected, and identified with the help of regional floras (Gamble & Fischer 1915–1935; Rao & Kumari 2002–2008). APG III (APG III 2009) classification was followed to classify the angiosperm species. The voucher specimens are deposited in the Botany Department Herbarium (BDH), Andhra University, Visakhapatnam.

 

 

Results and discussion

 

A total of 270 tree species representing 177 genera belonging to 55 families were recorded from the study area (Table 1; Images 1–5). As per the field observations 141 species were common, 78 species were occasional and 51 species were rare. Of the 55 families, 21 were represented by a single species and 21 other families with more than five species. Of the 177 genera, 128 were represented in the study area by a single species each. Fabaceae was the dominant family with 33 species followed by Rubiaceae with 15 species, Malvaceae, Moraceae and Phyllanthaceae with 13 species each, Rutaceae with 12 species and Lamiaceae with 11 species. According to Pragasan & Parthasarathy (2009), Euphorbiaceae, Moraceae, Rubiaceae and Rutaceae are dominant families in the southern Eastern Ghats, while Sandhyarani et al. (2007) reported that Euphorbiaceae, Rubiaceae, Moraceae and Lauraceae as the dominant families in the Eastern Ghats. The largest genera include Ficus with 12 species, followed by Diospyros (8 species), Albizia and Grewia (6 species each), Acacia and Bauhinia (5 species each). Sandhyarani et al. (2007) reported 25 species of Ficus, 12 species each of Acacia, Diospyros and Grewia as dominants in the Eastern Ghats of southern peninsular India. Pragasan & Parthasarathy (2009) documented 12 species of Ficus, eight species of Diospyros, six species each of Acacia and Terminalia in the southern Eastern Ghats of Tamil Nadu. Vegetation-wise analysis reveals that 45% of the taxa inhabit dry deciduous forests, 36% in moist deciduous forests, 28% in semi-evergreen forests, and 10% in thorny-scrub forests and 4% of trees occur in tropical dry evergreen forests. These findings are in conformance with the earlier observations of Reddy et al. (2009). Nativity element wise, the most dominant is the Indian element representing 45%, followed by Indo-Malaysian (23%), tropical Asia-Australia (7.4%), tropical Asia (6%), Indo-Myanmar (5.2%), tropical Africa-India (3.3%), tropical Africa-Asia (3%), tropical Africa Asia-Australia (2%) and other elements contributed 4% in the present study. Meher-Homji (1977) reported that the tropical dry deciduous forests of peninsular India represents 50% of Indian elements followed by Indo-Malayan elements 18.5% and tropical Africa/Malagassy-tropical Asian/Indian groups of elements constituting 4.2–7 %. In the present study, the most abundant tree species were Xylia xylocarpa (Fabaceae), Anogeissus latifolia (Combretaceae), Cleistanthus collinus (Phyllanthaceae), Dalbergia lanceolaria ssp. paniculata (Fabaceae) in tropical dry deciduous forests, Dillenia pentagyna (Dilleniaceae), Ficus semicordata (Moraceae), Mangifera indica (Anacardiaceae) and Pterocarpus marsupium (Fabaceae) in moist deciduous forests, Syzygium cumini (Myrtaceae), Michelia champaca (Magnoliaceae), Terminalia chebula (Combretaceae) in semi-evergreen forests, Alangium salvifolium (Cornaceae), Wrightia tinctoria (Apocynaceae), Acacia leucophloea (Mimosaceae) and Diospyros vera (Ebenaceae) in thorny scrub forests and Bridelia montana (Euphorbiaceae), Catunaregum tomentosa (Rubiaceae) and Holarrhena pubescens (Apocynaceae) in dry evergreen forests.

When compared with the data of the earlier reports, the enumerated species richness of 270 tree species was greater than the few inventories of tree species in other tropical forests viz., 103 species from Uppangala, central Western Ghats (Pascal & Pelissier 1996); 148 species from Varagalair, Anamalais (Ayyappan & Parthasarathy 1999); 157 species from Mudumalai Sanctuary (Suresh et al. 1996); 164 species from Biligiri Rangaswamy Sanctuary (Ramesh 2002) and 211 species in Huai Kha Khaeng, Thailand and 226 species in Barro Colorado Island, Panama (Condit et al. 2000). But, lesser than the 272 species from the southern Eastern Ghats of Tamil Nadu (Pragasan & Parthasarathy 2009); 673 species in Pasoh, Malaysia and 996 species encountered in Lambir, peninsular Malaysia (Condit et al. 2000).

 

 

 

 

 

 

Conclusion

 

Overall, the findings on the tree species diversity of the Eastern Ghats forests of northern Andhra Pradesh show a high species richness. Among the families, Fabaceae is the dominant family followed by Rubiaceae, Malvaceae, Moraceae and Phyllanthaceae. The most dominant nativity element is of Indian origin which comprises 45% followed by the Indo-Malaya region. From the total species of 560 trees of the entire Eastern Ghats, nearly half of the tree species diversity exists in the Eastern Ghats of northern Andhra Pradesh forests. In view of its richness and occurrence of rare species (51), intensive floristic studies need to be conducted for proper documentation and species wise ecological status assessment. Such studies will also aid focused conservation management as well as ensure sustainable utilization of plant resources in the Eastern Ghats forests of Andhra Pradesh.

 

 

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