Entomological Science (2008) 11, 301–313 doi:10.1111/j.1479-8298.2008.00281.x ORIGINAL ARTICLE Diversity of pselaphine beetles (Coleoptera: Staphylinidae: Pselaphinae) in eastern Thailand Watana SAKCHOOWONG1,2, Shûhei NOMURA3, Kazuo OGATA4 and Jariya CHANPAISAENG1 1Department of Entomology, Faculty of Agriculture, Kasetsart University, 2National Parks, Wildlife and Plant Conservation Department, Bangkok, Thailand; 3Department of Zoology, National Museum of Nature and Science, Tokyo, and 4Institute of Tropical Agriculture, Kyushu University, Fukuoka, Japan Abstract Pselaphine beetles (Coleoptera: Staphylinidae: Pselaphinae) are cosmopolitan, species-rich, and yet poorly studied, particularly in the tropics. We sampled beetles in three types of primary forest and two types of disturbed forest habitats in eastern Thailand to assess the utility of pselaphine beetles as bioindicators of forest disturbance. We simultaneously measured leaf litter mass, soil moisture, soil acidity and canopy cover at each site to infer which environmental factors affect pselaphine beetle diversity and abundance. At each site, pselaphine beetles were extracted from ten 1 m2 samples of leaf litter and soil with Tullgren funnels. We sampled 1867 adult beetles representing six supertribes, 51 genera and 114 morphospecies; 7% of the genera and 92% of the species were undescribed. Forest types differed significantly in species richness, abundance, diversity and evenness. Primary forest had greater numbers of species and individuals, and higher diversity indices (H′). Teak plantation and secondary forest had substantially fewer individuals and species of pselaphine beetles. Species composition differed between primary and degraded forests. Canopy cover, soil moisture, and leaf litter mass positively correlated with beetle species richness and abundance. Leaf litter mass and soil moisture were the two most important factors affecting the diversity of pselaphine beetle assemblages. Among the 114 morphospecies collected, 43 morphospecies were specific to two or three habitats and 64 morphospecies were found only in a single habitat. Thus pselaphine beetles appear to have rather narrow habitat requirements and their presence/absence was correlated with environmental differ- ences. These traits make pselaphine beetles a suitable bioindicator taxon for assessing forest litter diversity and monitoring habitat change. Key words: biodiversity, habitat monitoring, indicator species, litter-dwelling beetle, South-East Asia. INTRODUCTION and contribute valuable data to studies of comparative biodiversity and conservation (Stork 1988; Coddington Forest-litter-inhabiting arthropods are poorly under- et al. 1997). Pselaphine beetles (Coleoptera: Staphylin- stood because of their small size and complex habitats. idae: Pselaphinae) are among the most species-rich However, they play an essential role in nutrient cycling forest-litter-inhabiting group (Carlton 1999). They are also commonly known as ant-like litter beetles or short- winged mold beetles (Newton & Chandler 1989; Triple- horn & Johnson 2005) and are not economically Correspondence: Watana Sakchoowong, Forest Entomology important as pests, but play an important role in the soil and Microbiology Group, National Parks, Wildlife and Plant Conservation Department, 60 Praholyothin Road, ecosystem as predators of small invertebrates (Newton Chatuchak, Bangkok 10900, Thailand. & Chandler 1989). This subfamily is species-rich and Email: [email protected] cosmopolitan, and pselaphine beetles might therefore Received 11 January 2008; accepted 20 May 2008. be profitably used as indicator species for identifying © 2008 The Entomological Society of Japan W. Sakchoowong et al. Figure 1 Map showing the study sites in the eastern forest complex, Thailand, consisting of Khao Ang Rue Nai Wild- life sanctuary (KARN) where the habi- tats are primary mixed deciduous forest (PMDF) and secondary mixed decidu- ous forest (SMDF); Khao Sao Dao Wildlife sanctuary (KSD) where the habitats are moist evergreen forest (MEF) and teak plantation (TP); and Khao Kitchakut National Park (KKK) where the habitat is hill evergreen forest (HEF). habitat differences (Carlton 1999) and lack of distur- tuary (KSD) with a total area of 744.58 km2, and the bance in old-growth forests (Newton & Chandler Khao Kitchakut National Park (KKK) with a total area 1989). of 58.31 km2. Precipitation in KARN is blocked by high Although these beetles are diverse in the tropics, most mountains in KSD, which create a rain shadow, making of the 8400 described species are known from the tem- the KARN climate drier than that at KSD and KKK. perate zones (Newton & Chandler 1989; Carlton 1999), Annual precipitation is approximately 1600 mm at and their ecology has rarely been studied. Several studies KARN and 3800 mm at KSD. In eastern Thailand, the have revealed that pselaphine beetles are among the dry season lasts from November to March and the wet most diverse groups of beetles in leaf litter samples season lasts from May to October (Table 1; Thailand (Carton & Robinson 1998; Chung et al. 2000; Carlton Meteorological Department 2007). Differences in et al. 2004). The biology of pselaphine beetles, particu- precipitation and altitude, which ranges from 100 to larly the patterns of species distributions and commu- 1675 m a.s.l. in the study area, produce three different nity dynamics, has not been studied. Pselaphine beetles forest types (Kasetsart University 2007): mixed decidu- are efficiently collected with simple extraction methods ous forest, moist evergreen forest and hill evergreen (Berlese and Tullgren funnels), and they are readily iden- forest. To investigate the impact of human disturbance tified to genus level by using an identification guide on the local diversity of pselaphine beetles, we chose two to Asian pselaphine genera (S. Nomura, unpublished anthropogenically modified forest types for sampling: identification guide to subfamilies Protopselaphinae and secondary mixed deciduous forest and teak plantation Pselaphinae of Asia (Staphylinidae: Protopselaphinae; (Tectona grandis L.). The forest types are described in Pselaphinae), 2006; Chandler 2001). detail below. To examine whether pselaphine beetles might be useful as indicators of forest disturbance, we examined Primary mixed deciduous forest species diversity and abundance in five forest habitat The primary mixed deciduous forest (PMDF) was domi- types in eastern Thailand and determined which species nated by Lagerstroemia venusta Wall., Lagerstroemia indicate forest habitat type. cuspidata Wall., Pterocarpus macrocarpus Kurz, Sur- egada multiflorum (A. Juss.) Baill. and Syzygium perga- MATERIALS AND METHODS mentaceum (King) P. Chantar. & J. Parn. A PMDF site was established in the Lum Jang Wat subdistrict in Study sites KARN at 13°16′25″N, 101°44′44″E, 155 m a.s.l. The eastern forest complex of Thailand (Fig. 1) consists of two wildlife sanctuaries and one national park: the Moist evergreen forest Khao Ang Rue Nai Wildlife Sanctuary (KARN) with a A moist evergreen forest (MEF) site was established in total area of 1030 km2, the Khao Soi Dao Wildlife Sanc- the Ban Thung Krang subdistrict at 13°01′08″N, 302 Entomological Science (2008) 11, 301–313 © 2008 The Entomological Society of Japan Pselaphine diversity in eastern Thailand Table 1 Climatic and microenvironmental variables in the study sites in eastern Thailand in 2006 DWD Site Climatic variables January March May July September November KARN Rainfall (mm) 0 101.2 220.5 193.6 404.0 9.0 Humidity (%) 60.5 64.5 65.0 68.0 71.5 54.0 Temperature (°C) 26.6 29.5 29.1 28.7 28.0 28.1 KSD and KKK Rainfall (mm) 2.0 24.9 583.4 705.9 559.1 40.3 Humidity (%) 67.0 75.0 74.5 81.5 80.0 67.0 Temperature (°C) 26.6 28.4 28.4 27.8 27.5 28.2 Site/Forest type Microenvironmental variables KARN/PMDF Soil moisture (%) 10.0 8.0 20.6 18.4 22.3 11.7 Soil acidity (pH) 6.5 6.8 6.7 6.9 6.4 6.1 Canopy cover (%) 95.9 94.6 95.2 96.9 92.8 95.4 Litter wet mass (kg) 1.6 1.4 1.4 2.4 1.8 1.9 KARN/SMDF Soil moisture (%) 8.0 7.8 28.7 28.7 16.6 7.4 Soil acidity (pH) 6.7 6.7 7.0 6.4 6.4 6.9 Canopy cover (%) 84.2 89.4 88.4 91.7 86.8 83.9 Litter wet mass (kg) 0.6 1.2 0.9 1.3 1.1 0.8 KSD/MEF Soil moisture (%) 15.0 10.7 48.5 44.5 35.9 18.5 Soil acidity (pH) 6.2 6.3 6.7 6.6 6.4 6.4 Canopy cover (%) 93.6 92.3 93.7 94.6 92.5 89.9 Litter wet mass (kg) 2.3 1.5 1.6 2.1 2.4 3.0 KSD/TP Soil moisture (%) 9.1 8.0 40.8 25.9 15.7 9.6 Soil acidity (pH) 6.1 6.3 6.4 6.3 6.1 6.3 Canopy cover (%) 39.4 37.0 86.8 80.8 88.4 50.5 Litter wet mass (kg) 0.9 0.8 0.7 0.9 1.2 1.4 KKK/HEF Soil moisture (%) 22.0 25.9 52.3 47.6 35.9 21.5 Soil acidity (pH) 5.9 5.8 5.7 5.9 6.1 5.8 Canopy cover (%) 86.6 94.6 93.6 92.3 89.9 92.6 Litter wet mass (kg) 1.4 2.1 0.9 1.6 1.5 2.6 KARN, Khao Ang Rue Nai Wildlife Sanctuary; KSD, Khao Soi Dao Wildlife Sanctuary; KKK, Khao Kitchakut National Park; PMDF, primary mixed deciduous forest; SMDF, secondary mixed deciduous forest; MEF, moist evergreen forest; HEF, hill evergreen forest; TP, teak plantation; D, dry season; W, wet season (Thailand Meteorological Department 2007). 102°12′46″E, 329 m a.s.l. The dominant tree species The Royal Forest Department has since relocated the were Dipterocarpus alatus Roxb., Mallotus peltatus villages and restored the forest in these areas, which has Muell.