Plant diversity in the threatened sub-tropical grasslands of Nepal N.B. Peet a, *, A.R. Watkinson b , D.J. Bell a , B.J. Kattel c a School of Biological Sciences, University of East Anglia, Norwich, Norfolk NR4 7TJ, UK b Schools of Environmental and Biological Sciences, University of East Anglia, Norwich, Norfolk NR4 7TJ, UK c Department of National Parks and Wildlife Conservation, P.O. Box 860, Kathmandu, Nepal Received 9 February 1998; received in revised form 20 August 1998; accepted 21 August 1998 Abstract Previously extensive tall grasslands, and their associated fauna, are now restricted to small fragments in protected areas in low- land Nepal and northern India. Conservation management of the remaining grasslands has been hindered by the lack of a grassland classi®cation. A classi®cation of the grasslands in four protected areas in Nepal is presented. Two hundred and forty six plant species were recorded and nine species assemblages, with eight phases, were identi®ed. Royal Chitwan National Park contained the greatest diversity of assemblages, whilst Royal Bardia National Park and Royal Suklaphanta Wildlife Reserve, were of conserva- tion signi®cance for the occurrence of an Imperata cylindrica assemblage and its associated fauna. Early successional assemblages dominated by Saccharum spontaneum and Phragmites karka predominated in Koshi Tappu Wildlife Reserve. The spatial and tem- poral distribution of grassland assemblages is primarily in¯uenced by ¯uvial processes but also by ®re, cutting and grazing. Changes in the impact of these disturbances, for example as a result of dam building or a change in the ®re regime, will alter the diversity and distribution of the plant assemblages together with their associated fauna. Immediate conservation action should involve control- ling grazing in Koshi Tappu, removing invading woody species from Imperata cylindrica grassland and mapping the distribution of assemblages in all protected areas. # 1999 Elsevier Science Ltd. All rights reserved. Keywords: Classi®cation; Grassland; Nepal; Protected area; Terai 1. Introduction Protected areas in the lowland Terai of Nepal contain some of the last remaining examples of sub-tropical tall grasslands (Fig. 1) in the Indian sub-continent (Bell and Oliver, 1992). These grasslands are key sites for biodi- versity conservation, not only as a restricted area habi- tat, but also for the range of endangered faunal species which they support, including tiger Panthera tigris, greater one-horned rhinoceros Rhinoceros unicornis, hispid hare Caprolagus hispidus and Bengal ¯orican Eupodotis bengalensis (IUCN, 1993). Formerly the habitat extended across north-eastern India, southern Nepal and northern Bangladesh, being concentrated in the valleys of the Ganges and Brahmaputra rivers and their tributaries (Bell and Oliver, 1992). Today, it is almost entirely restricted to 10 protected areas in northern India and four protected areas in the Nepalese Terai (Oliver, 1985). These remaining grassland fragments are also small; the largest area in Nepal is found in Royal Chitwan National Park and occupies c.20% of the total park area of 93 200 ha (IUCN, 1993). A consequence of the loss of grassland habitat is a decline in the asso- ciated fauna. A vital pre-requisite for the conservation of these threatened faunal populations is therefore to investigate the diversity, structure and distribution of the grasslands in which they occur. Current management of the Nepalese grasslands involves annual cutting and burning, both by local people and by protected area sta. This form of man- agement partly derives from the annual grass harvest, which provides subsistence resources to local commu- nities, in the form of cane and thatch for building (Lehmkuhl et al., 1988; Vaa Saetre, 1993; Brown, 1997). It also results from a belief that burning is the most suitable form of management in the grasslands, as it is thought to prevent succession to forest, provide forage for ungulates as the grasslands regenerate and prevent damaging hot burns later in the dry season. The impact of cutting and burning on the grassland communities, together with other important disturbance factors such as grazing and ¯ooding, are however, poorly understood BIOLOGICAL CONSERVATION Biological Conservation 88 (1999) 193±206 0006-3207/99/$Ðsee front matter # 1999 Elsevier Science Ltd. All rights reserved. PII: S0006-3207(98)00104-9 * Corresponding author. Tel.: 01603 250361; e-mail: nic.peet@bird- life.org.uk.