In Indo-Burma

Chapter 5. The status and distribution of dragonflies and damselflies (Odonata) in Indo-Burma Graham Reels1, Rory Dow2, Matti Hämäläinen3 and Do Manh Cuong4 5.1 Overview of the regional Odonata with reference to the freshwater ecoregions ..........................................................................................90 5.1.1 Upland rivers ........................................................................................................................................................................................................92 5.1.2 Floodplain rivers and wetland complexes .....................................................................................................................................................92 5.1.3 Coastal rivers ........................................................................................................................................................................................................94 5.1.4 Large river deltas .................................................................................................................................................................................................95 5.2 Conservation status ......................................................................................................................................................................................................95 5.3 Patterns of species richness and endemism .............................................................................................................................................................97 5.3.1 Threatened species ..............................................................................................................................................................................................97 5.3.2 Data Deficient species .......................................................................................................................................................................................97 5.4 Major threats to dragonflies .......................................................................................................................................................................................99 5.5 Conservation recommendations .............................................................................................................................................................................100 5.5.1 Conservation measures ....................................................................................................................................................................................100 5.5.2 Research action required .................................................................................................................................................................................100 5.6 References .....................................................................................................................................................................................................................101 5.1 Overview of the regional Odonata of evergreen rainforest that remain are in southern Myanmar, with reference to the freshwater the Cardamom Mountains of southwest Cambodia, and the ecoregions Annamite Mountains of central and southern Lao PDR and Viet Nam (Figure 5.1). Extensive tracts of broadleaved deciduous Indo-Burma lies entirely within the Asian seasonal tropics. forest remain in eastern Myanmar, northern Thailand and Much of the region, including eastern Myanmar, northwestern northern and eastern Cambodia. and southern Thailand, Peninsula Malaysia (the northern tip of which is in Indo-Burma), southern Lao PDR, eastern and The region covers a wide altitudinal range, from sea level to coastal Cambodia and almost the whole of Viet Nam, was 3,000 m. Much of the northern part of the region (eastern historically covered in broadleaved evergreen tropical rainforest Myanmar, northern Thailand, northern Lao PDR and (Primack and Corlett 2005). However, a large swathe of the northern Viet Nam) is mountainous, while the southern half is Indo-Burma interior, comprising much of northern Thailand, predominantly low-lying with some exceptions, most notably the northern Lao PDR and western Cambodia, is in a rain shadow southern extension of the Annamite Mountains in Viet Nam cast by the surrounding uplands, and in this area the original (Figure 5.1). Drainage through the region is predominantly vegetation would have comprised drier forest types (Primack north-south and west-east and comprises three major catchments and Corlett 2005). These highlands include the Shan Plateau originating in uplands north of Indo-Burma: the Salween to and the Xianghoang Plateau to the north, the Annam Plateau the west, draining southeast Myanmar and extreme northwest to the east, the Dawna Range to the west, and the Chuor Phnum Thailand, the Red River and Black River system draining (Cardamom) Mountains to the south. Herbaceous swamps would northern Viet Nam, and the Mekong, draining most of the vast also have been present on alluvial plains in the lower basins of the area in-between (Figure 5.1). A fourth river system, the Chao Mekong, Song Hong and Chao Phraya, now largely converted to Phraya, is smaller, having an Indo-Burmese provenance, and rice paddy, where seasonal rainfall led to flooding conditions that runs from north Thailand south to Bangkok. The Mekong River precluded forest establishment (Corlett 2005). Most of the forest system is by far the largest in Indo-Burma, occupying the rain cover of Indo-Burma has been lost due to rapidly intensifying shadow interior and including in its basin the Tonlé Sap Lake anthropogenic impacts in recent centuries. The largest tracts in Cambodia – the largest body of fresh water in Southeast Asia 1 Graham Reels, 87 Lychee Road North, Fairview Park, Yuen Long, Hong Kong. [email protected]. 2 Dr Rory Dow, Netherlands Centre for Biodiversity Naturalis, Leiden, The [email protected] . 3 Dr Matti Hämäläinen, Netherlands Centre for Biodiversity Naturalis, Leiden, The [email protected] . 4 Do Manh Cuong, Entomology and Zoology Department, Military Institute of Hygiene and Epidemiology, Viet Nam. [email protected]. 90 (CEPF 2007), which acts as a seasonal sump for the Mekong area encompassing the northern parts of Thailand, Lao PDR and (Dudgeon 1999) – and the vast deltaic region of the southern tip Viet Nam, and tropical southern China, is particularly rich and of Viet Nam. was identified as a distinct subregion for odonate biodiversity by van Tol and Rozendaal (1995), a suggestion given further The Indo-Burma Hotspot, which includes tropical southern credence by Wilson and Reels (2003). As noted by Hämäläinen China in addition to the more narrowly defined area covered (2004), the area covered by the present assessment does not form in this assessment, ranks in the top ten biodiversity hotspots a single zoogeographical unit, with an odonate fauna comprising in the world for ‘irreplaceability’ and in the top five for ‘threat’ Sondaic, Sino-Himalayan and Indochinese elements, in addition (CEPF 2007). This high biodiversity value is reflected in the to Indo-Burmese. odonate fauna of the hotspot, with a higher diversity of species and genera than anywhere else in the Oriental Region (Kalkman The present assessment covers some 473 odonate species (in et al. 2008), probably due to the combined effect of its size, 150 genera), of which approximately 160 (34%) are thought to mountainous terrain, large rivers and variety of forest types. The be endemic or near-endemic in Indo-Burma (the real figure for Figure 5.1 Forest cover and topography within the Indo- Burma assessment region, based on the Global Land Cover 2000 data (Stibig et al. 2003). Tree cover Broadleaved, deciduous, closed Broadleaved, deciduous, open Broadleaved, evergreen Mixed leaf type 0 75 150 300 Kilometers Needle-leaved, deciduous Needle-leaved, evergreen Coordinate system: World Cylindrical Equal Area Regularly flooded, fresh water Source: IUCN Indo-Burma Freshwater Biodiversity Assessment The boundaries and names shown and the designations used on this map do not Regularly flooded, saline water imply any official endorsement, acceptance or opinion by IUCN. 91 endemics is uncertain, given that the region impinges on, and The 16 freshwater ecoregions fall into four broad ‘Major Habitat is biogeographically contiguous with, parts of Myanmar, China Types’: upland rivers, floodplain rivers and wetland complexes, and the Malay Peninsula). Fourteen species are considered coastal rivers, and large river deltas (WWF/TNC 2008). threatened. The region has a low proportion (30.5%) of species in the cosmopolitan families Coenagrionidae and Libellulidae, 5.1.1 Upland rivers most members of which are associated with open, lentic or slow-flowing waters. The majority of species are forest- and Two very different ‘upland river’ ecoregions have been identified lotic-associated, reflecting the historical biogeography of the in the Indo-Burma region. region. New species are still being described from Indo-Burma on a fairly regular basis (for example, Do 2011a, 2011b; Do and The Upper Salween ecoregion extends in a long narrow curve Karube 2011; Sasamoto et al. 2011) and it is likely that the real from eastern Tibet, through Szechuan and Yunnan, and ends total exceeds 500 species (Hämäläinen 2004). Knowledge of in northeast Myanmar,

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