UvA-DARE (Digital Academic Repository) Effects of El Niño and large-scale forest fires on the ecology and conservation of Malayan sun bears (Helarctos malayanus) in East Kalimantan, Indonesian Borneo Fredriksson, G.M. Publication date 2012 Link to publication Citation for published version (APA): Fredriksson, G. M. (2012). Effects of El Niño and large-scale forest fires on the ecology and conservation of Malayan sun bears (Helarctos malayanus) in East Kalimantan, Indonesian Borneo. General rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulations If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. UvA-DARE is a service provided by the library of the University of Amsterdam (https://dare.uva.nl) Download date:26 Sep 2021 Chapter 3 Movements and activity patterns of female sun bears in East Kalimantan, Indonesian Borneo: implications for conservation With David L. Garshelis 54 Chapter 3 Abstract Sun bears (Helarctos malayanus) in Indonesia are primarily threatened by destruction of their forest habitat, with poaching for body parts a secondary threat. Protected areas are increasingly becoming important for the conservation of this species, as non-protected forest areas are rapidly being converted to other landuses, but relevant data on spatial and habitat requirements of sun bears are limited. Radio-telemetry was used to study the movements and activity patterns of Bornean sun bears (H. m. euryspilus) in a small lowland rain forest reserve in East Kalimantan, Indonesian Borneo. Three wild and two rehabilitated-released female bears were fitted with motion-sensitive VHF radio-collars; three of these bears were tracked contin- uously for 1-3 years during 1999-2003. A total of 5,470 locations were recorded. Home range sizes (12-month period) were 4-5 km2 (95% MCP and 95% fixed kernel). Home range overlap was considerable. Small home ranges may have been related to a diet composed predominantly of insects. No mast fruiting event occurred during the period of study. Activity monitoring (169 days, 4,049 hours, 24,294 readings) revealed that sun bears were predominantly diurnal and crepuscular throughout the year with activity commencing about 0.5 h before sunrise and lasting until 2.5 h after sunset, and low levels (20-30%) of activity at night. Bears were active 61.6% of the day (14.8 ± 2.3 hours), on average, with higher levels of activity associated with insect feeding than fruit feeding. A combination of relatively small home range size, bounded entirely within the reserve, and avoidance of areas with human disturbance (trails, burned forest) suggest that small re- serves are still valuable for the conservation of sun bears. Long-term persistence will depend on prevention of poaching and maintaining connectivity to other forested areas. Movements and activity patterns of female sun bears 55 Introduction Habitat reduction, combined with unsustainable levels of hunting, has put many bear populations at risk (Garshelis, 2009). Ursids (bears) generally have large home ranges (Garshe- lis 2004), often with distinct movements to seasonal ranges in response to temporal variations in the distribution and availability of food (Garshelis and Pelton 1981, Blanchard and Knight 1991, Joshi et al. 1995, Ferguson et al. 1999, Liu et al. 2002, Hwang et al. 2010, Castellanos 2011). Radio-telemetry has provided important insights into the lives of bears, and has been instrumental for obtaining data on movement patterns and habitat use (Garshelis 2004) that has been of use for management and conservation planning. Although this technology has been used for several decades to study bears in northern regions (see Garshelis 2004) only a handful of radio-telemetry studies have been carried out on bears in the tropics (Nomura et al. 2004, Wong et al. 2004, Paisley and Garshelis 2006, Hwang et al. 2010, Castellanos 2011). The sun bear (Helarctos malayanus), ranging throughout much of Southeast Asia (Fig. 1), has been listed as ‘Vulnerable’ based on significant habitat loss over the last 30 years (Fredriks- son et al. 2008). Southeast Asia experiences some of the highest levels of forest conversion in the world including deforestation, forest degradation and fragmentation (FAO 2010, Sodhi et al. 2010, Broich et al. 2011, Miettinen et al. 2011), and clearing for rapid expansion of the plantation sector (Koh 2007, Butler and Laurance 2008, Fitzherbert et al. 2008). Levels of threat to this bear species vary across the region with poaching for body parts being the greatest threat on mainland Southeast Asia (Dang 2006, Nea and Nong 2006, Vinitpornsawan et al. 2006), whereas habitat loss and fragmentation are currently considered the greatest threat in Indonesia and Malaysia (Tumbelaka and Fredriksson 2006, Wong 2006). Sun bears are a forest-dependent species, found in a variety of forest types (Fredriks- son et al. 2006a, Steinmetz et al. 2011) up to 2500 m above sea level (a.s.l.) and have been found to persist in logged-over (Wong et al. 2004, Meijaard et al. 2005, Linkie et al. 2007), and other disturbed forest areas (Fredriksson et al. 2006b). They have even been found to make foraging excursions into oil palm plantations (Nomura et al. 2004). Sun bears on the island of Borneo have been recognized as a subspecies, H. m. euryspilus, substantially (~30%) smaller than their mainland and Sumatran counterpart H. m. malayanus (Horsfield 1825, Meijaard 2004). Some 45% of the extant distribution range of sun bears lies in Indonesia (IUCN Bear Specialist Group, Japan Mapping Workshop 2006), making it the single most important country for the conservation of this species. Some 24 million ha of forest are under some form of protected status on Sumatra and Kalimantan (Indonesian Borneo) (FWI/GFW 2002), although the area of forest under protection has not increased in the last decade (FAO 2011). Protected 56 Chapter 3 Figure 1. Sun bear distribution range in Southeast Asia and location of the Sungai Wain Protection Forest, East Kalimantan, Indonesian Borneo. areas are seen as one of the most effective tools for conservation in the tropics (Kramer et al. 1997, Bruner et al. 2001, Terborgh et al. 2002), despite the fact that the effectiveness of many of these protected areas is limited due to lack of, or weak, in-situ management implementa- tion (e.g. FWI/GFW 2002, Kinnaird et al. 2003, Curran et al. 2004, Gaveau et al. 2009, Linkie et al. 2010, Harrison 2011). The conservation value of large expanses of unprotected logged- over areas in Borneo has also been highlighted (Meijaard et al. 2005, Meijaard and Sheil 2008), although many of these areas are under further threat by corporate conversion (Butler and Laurance 2008). The size of protected areas, or available safe habitat, is important for many species, especially those with large ranges (Powell et al. 1996, Beringer et al. 1998, Woodroffe and Ginsberg 1998, Woodroffe 2001, Wielgus 2002). Movements and activity patterns of female sun bears 57 Lowland dipterocarp forest, richest in terms of biodiversity and previously covering large expanses of Borneo, is now becoming increasingly rare, fragmented, and affected by vari- ous forms of human disturbance (Curran et al. 2004). In order assess the spatial, ecological, and habitat requirements of sun bears in this threatened forest type in Kalimantan, we studied their ranging and activity patterns in relation to fruiting patterns and human disturbance in a small lowland forest reserve in East Kalimantan, Indonesian Borneo. Methods Study site This study was carried out in a lowland dipterocarp forest, the Sungai Wain Protection Forest (SWPF), near Balikpapan, East Kalimantan, Indonesian Borneo (1º 05’ S and 116º 49’ E), at the easternmost edge of the sun bears’ distribution range (Fig. 1). The reserve covers a watercatchment area of circa 10,000 ha. Approximately 50% of the reserve was burned by forest fires in March-April 1998 (Fredriksson 2002), during one of the most severe El Niño- Southern Oscillation (ENSO) related droughts ever recorded (McPhaden 1999), leaving an unburned central core of 4,000 ha of primary forest as well as unburned forest along rivers. The geomorphology of the reserve is of eroded sedimentary formations with a relatively low elevational range (30 - 150m), intersected by many small rivers. No roads traverse the reserve and access is only by foot. One main trail leads northwards from the nearest village and forest edge following a ridge separating 2 main sub-watersheds in the reserve. Less than 2 km before this ends, the track splits with the west branch descending to a research station located in the middle of the reserve. This trail was used as the main access route to the research station, for ferrying logistical supplies to the research station twice a week by porters, as well as for varied research purposes. There was little other foot traffic on this trail. Fruiting phenology, and rainfall The most common tree families above 10 cm dbh (diameter at breast height) were Euphorbiaceae, Dipterocarpaceae, Sapotaceae and Myrtaceae. The relative dominance of Dip- terocarpaceae increased substantially in the larger size classes. Together, the 25 most common species formed 40% of the total stem density (van Nieuwstadt 2002).