South Asian Biomes

by

Priya Davidar

• LAST REVIEWED: 15 January 2021
• LAST MODIFIED: 26 May 2021
• DOI: 10.1093/obo/9780199830060-0163

Introduction

South Asia includes regions south of the Himalayan Mountains bounded by the Indian Ocean, West Asia, Central Asia, Southeast Asia, and East Asia. The countries within South Asia are Afghanistan, Bangladesh, Bhutan, India, Nepal, Pakistan, and Sri Lanka. South Asia is the most densely populated region in the world with more than 1.7 billion people in 5.1 million square kilometers of territory. This article considers the biomes south of the Himalayan Mountains, including the Himalayas and the archipelagoes such as the Maldives-Lakshwadeep-Chagos in the Indian Ocean and the Andaman and Nicobar Islands off Southeast Asia since these are included within the territory of India. Treatment is challenging due to the inherent complexity of the natural ecosystems, the variation in quality of the source materials, and the lack of information on certain ecosystems. Limits between biomes are difficult to delineate due to strong climatic gradients that juxtapose different ecosystems within short distances. These issues are discussed in the respective sections.

Identifying Biomes of South Asia

A biome is a geographical area with a particular configuration of species and organisms maintained by environmental parameters such as temperature, soil, light, and water. The life zones system in Holdridge 1947 forms the basis for biome classification, and it was later simplified in Whittaker 1978, and climatic seasonality is included in Walter 1955. In South Asia, forest biomes are fairly well documented due to the groundwork laid by early foresters in works such as Brandis 1908 and Champion and Seth 1968 (revised edition of Forest Types in India and Burma [Nature 143, 387, 1936]). However, other biomes have not been well studied. The authors of Gadgil and Meher-Homji 1986 classify forty-three vegetation types based on the French Institute School of Gaussen, et al. and other sources. Based on this work, Udvardy 1975 identifies thirteen biogeographical zones from South Asia. For the purposes of identifying sites for protected areas, Rodgers and Panwar 1988 identifies ten biogeographic zones and twenty-six biotic provinces. More recently Roy, et al. 2006 identifies thirty-five categories of forest cover and seventeen vegetation types using the life zone classification (HLZ) in Holdridge 1947, with a 1 million scale biome map of 200 m resolution. The follow-up is the 1: 50,000 scale map in Roy, et al. 2015. However, there is no integrated classification based on climate and geography. Therefore, this biome classification is based on the World Wide Fund for Nature (WWF). Terrestrial Ecoregions of the World (see Olson, et al. 2001), is the most recent with extensive geographical coverage and easy online access. Problems of redundancy and overlap were encountered, and discretion was exercised in merging ecoregions based on climate or geography. A summary of past geological history and climate is included in conjunction with present climate and future changes. Conservation challenges with regard to land use and climate change are addressed. The eight terrestrial biomes described are: (1) tropical and subtropical wet broadleaf forests; (2) tropical moist deciduous forests; (3) tropical dry broadleaf forests;(4) temperate and mixed broadleaf and coniferous forests; (5) tropical, subtropical, and temperate coniferous forests; (6) grasslands and savannas; (7) desert; (8) mangroves. Different ecoregions, which are geographically defined areas containing distinct assemblages and communities, have been identified within a biome.

• Brandis, D. 1908. Obituary notices of fellows deceased: Sir Dietrich Brandis, 1824–1907. Proceedings of the Royal Society Series B 80: iii–vi.

  Provides a summary of the contributions of Sir Dietrich Brandis to the development of forestry in the Indian subcontinent.

• Champion, H. G., and S. K. Seth. 1968. A revised survey of the forest types of India. New Delhi: Government of India.

  Treats forest types of India based on geography, tree assemblages, and vegetation characteristics.

• Gadgil, M., and V. M. Meher-Homji. 1986. Localities of great significance for the conservation of India’s biodiversity. Proceedings of the Indian Academy of Sciences 165–180.

  The authors classify the natural vegetation of India into forty-three types and estimate their geographical extent.

• Holdridge, L. R. 1947. Determination of world plant formations from simple climatic data. Science 105:367–368.

  DOI: 10.1126/science.105.2727.367

  The Holdridge life zones system is a classification system for earth’s terrestrial areas using a global bioclimatic scheme based on temperature, rainfall, and potential evapo-transpiration.

• Olson, D. M., E. Dinerstein, E. D. Wikramanayake, et al. 2001. Terrestrial ecoregions of the world: A new map of life on Earth; A new global map of terrestrial ecoregions provides an innovative tool for conserving biodiversity. BioScience 51.11: 933–938.

  DOI: 10.1641/0006-3568(2001)051[0933:TEOTWA]2.0.CO;2

  The authors provide a new global map of terrestrial ecoregions as an innovative tool for conservation planning at the global scale. Ecoregions are distinct biotas nested within biomes and are a practical definition for conservation planning and action. A total of 867 terrestrial ecoregions were grouped into fourteen different biomes.

• Rodgers, W. A., and H. S. Panwar. 1988. Planning a wildlife protected area network in India. 2 vols. Dehradun, India: Wildlife Institute of India.

  Vol. 1, The Report; Vol. 2, State Summaries. The authors divide the Deccan Peninsula into ten biogeographic zones and twenty-six biotic provinces based mainly on the distribution of large mammals with the objective of establishing protected areas for wildlife conservation.

• Roy, P. S., M. D. Behera, M. S. R. Murthy, et al. 2015. New vegetation type map of India prepared using satellite remote sensing: Comparison with global vegetation maps and utilities. International Journal of Applied Earth Observation and Geoinformation 39:142–159.

  DOI: 10.1016/j.jag.2015.03.003

  The authors produce a vegetation map using remote sensing and 15,565 field points providing spatial information on one hundred vegetation types. The mapping was carried out on the distribution of major natural, semi-natural, and managed vegetation types in a hierarchical manner.

• Roy, P. S., P. K. Joshi, S. Singh, et al. 2006. Biome mapping in India using vegetation type map derived using temporal satellite data and environmental parameters. Ecological Modelling 197.1–2: 148–158.

  DOI: 10.1016/j.ecolmodel.2006.02.045

  The study identifies nineteen Holdridge life zones, seven biomes, and nineteen sub-biomes in the Indian subcontinent. The major biomes delineated are (1) tropical rain forests, (2) tropical wet evergreen forests, (3) tropical moist forests, (4) tropical dry forests, (5) tropical thorn forests, (6) tropical desert, and (7) Himalayan temperate tundra. Available online by subscription or for purchase.

• Udvardy, M. D. F. 1975. A classification of the biogeographical provinces of the world. Morges, Switzerland: International Union for Conservation of Nature and Natural Resources.

  Widely used classification of biogeographical realms and terrestrial biomes. Identifies eight biogeographical realms. The Indo-Malayan realm has been categorized into twenty-eight ecosystems of which fourteen are in South Asia, including oceanic islands.

• Walter, H. 1955. Die Klimadiagramme als Mittel zur Beurteilung der Klimaverhaltnisse für okologische, vegetations kundliche und landwirtschaftliche Zwecke. Berichte der deutschen botanischen Gesellschaft 68:331–344.

  Walter developed methods for classifying vegetation based on PET (Potential Evapo-Transpiration) and seasonality.

• Whittaker, R. H. 1978. Approaches to classifying vegetation. In Classification of plant communities. Edited by R. H. Whittaker, 1–33. The Hague: Junk.

  DOI: 10.1007/978-94-009-9183-5_1

  This volume is an important contribution to plant community ecology, particularly productivity, diversity, and succession.