Tropical Natural History 13(1): 39-48, April 2013 2013 by Chulalongkorn University Activity Budget of the Impressed Tortoise, Manouria impressa (Günther, 1882), in Phu Luang Wildlife Sanctuary, Thailand PRATYAPORN WANCHAI1,2, CRAIG B. STANFORD3, ART-ONG PRADATSUNDARASAR2, KAMPANAT THARAPOOM4 AND KUMTHORN THIRAKHUPT2* 1Biological Science Program, Faculty of Science, Chulalongkorn University, Bangkok 10330, THAILAND 2Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, THAILAND 3Department of Anthropology, University of Southern California, Los Angeles, CA 90089, USA 4Department of Biology, Faculty of Science, Silpakorn University, Nakhon Pathom, 73000, THAILAND * Corresponding author. E-mail: [email protected] Received: 14 December 2012; Accepted: 15 March 2013 ABSTRACT.– The activity budget of the impressed tortoise, Manouria impressa (Günther, 1882), was studied at Phu Luang Wildlife Sanctuary, Loei Province, Thailand, from January 2010 - October 2011. A total of fourteen M. impressa individuals, consisting of ten adults (five males and five females) and four juveniles, were radio-tracked. Hiding was the most frequently observed activity in both the wet and dry seasons. The frequency of active behavior in the wet season was higher than in the dry season. Tortoises were found to be active at ambient temperatures ranging from 12.0 ºC - 30.0 ºC, and a relative humidity from 60% - 100%. The year-round averages for air temperature and relative humidity for activity in males, females and juveniles were not significantly different. For all individuals, there was no significant difference in temperature between each active behavior. Two cases of nesting were also observed. KEY WORDS: Radio-tracking, home range, Manouria impressa Environmental Policy and Planning have INTRODUCTION classified it as an endangered species. This species appears to be rare in its The impressed tortoise, Manouria natural habitat due to habitat destruction, impressa (Günther, 1882) (Reptilia: poaching for food and collecting for the pet Testudines), is distributed throughout the trade (van Dijk and Palasuwan, 2000). montane areas of Southeast Asia, including However, it is difficult to maintain in Myanmar, Thailand, Laos, Vietnam, captivity and has only recently been captive- Cambodia and Malaysia (Ernst and Barbour, bred. The natural history of M. impressa is 2001, Fritz and Havas, 2007). Within poorly known, and most recently accepted Thailand this species is found in the data have been based on short term field mountains of northern, northeastern and studies, with no long term study of its western Thailand (Thirakhupt and van Dijk, ecology in the wild being available. 1994; Cox et al., 1998). The IUCN Red List McMorris and Burns (1975) reported that (2000) classifies M. impressa as a M. impressa spends much of its time hiding vulnerable species and it is protected under under leaf litter, and Nutaphand (1979) Appendix II of CITES. In Thailand, the reported that they are active during the rainy impressed tortoise is a protected species season (May - October) when they eat grass under wildlife conservation law whilst the shoots and look for mates. In contrast, Office of Natural Resources and 40 TROPICAL NATURAL HISTORY 13(1), APRIL 2013 Weissinger (1987) reported the species is types, including dry deciduous dipterocarp, only active during the rainy season and mixed deciduous, dry evergreen, montane Chan-ard et al. (1996) reported that, for the evergreen and coniferous forests, plus M. impressa kept in an enclosure at Phu tropical grassland. This study was Luang Wildlife Research Station, they conducted at 900 – 1400 m above mean sea usually entered brumation during November level (amsl) (Chan-ard et al., 1996). and emerged after the first substantial rain, which usually falls in late February. Based Radiotelemetry.– Animals were radio- on a study of six M. impressa (four males tracked from January 2010 through to and two females) in the Central Cardamom October 2011 inclusive. A total of 14 M. Protected Forest on the Cardamom impressa individuals comprised of ten Mountains in southwest Cambodia from adults (five males and five females) and four September 2007 - March 2008, Koulang juveniles (Table 1) were tracked using (2008) reported that the mean ambient radio-transmitters (148 MHz). The post- temperature near the hiding place was 23.9 attachment transmitter weights for adults + 1.8 °C (range of 20.0 °C - 29.2 °C), whilst and juveniles were 35 g and 25 g, that at the microhabitat of the hiding place respectively, and so did not exceed the was 20.6 +1.0 °C (range of 18.0 °C - 22.7 recommended guideline of 5% of the body °C). Normally, the microhabitat temperature weight (White and Garrott, 1990). Each is significantly lower compared to the tortoise was located 6 – 10 times per month ambient temperature of the hiding places. by direct observation, using an ATS receiver The purpose of this study was to describe (Model FM16) and a handheld ATS 3 the annual activity patterns and any element folding Yagi antenna. When a differences in activity between the wet and tortoise was located, the activity when first dry seasons, and the preferred microhabitat seen was recorded in terms of being active of M. impressa. This study provides new or inactive, where the active state was basic information on its ecology and defined into one of the seven categories of behavior that could be used for captive (1) walking, (2) eating, (3) basking (staying breeding and conservation management. on the forest floor, fully exposed to the sun, usually with limbs spreading wide and neck MATERIALS AND METHODS stretching out), (4) resting (immobile; staying in the open or in partial cover, Study Sites.– The study was carried out in plastron touching the ground, neck and Phu Luang Wildlife Sanctuary (PLWS), limbs mostly extended), (5) soaking (sitting located in the south of Loei Province in the in a shallow stream or swamp), (6) Northeast of Thailand at 17 3' – 17 24'N courting/mating (male following a female, and 101 16' – 101 21'E. PLWS covers an circling around her, and mounting or area of 897 km². The climate is attempting to mount), and (7) nesting characterized by a rainy season (May – (female building or guarding a nest). October) and a dry season that is further Individuals hiding under leaf litter or rocks subdivided into the cold-dry (November – and fallen branches were classified as February) and hot-dry subseasons (March – “inactive”. April). The sanctuary contains various forest WANCHAI ET AL. — ACTIVITY BUDGET OF THE IMPRESSED TORTOISE 41 TABLE 1. Home range sizes and specimen data for 13 M. impressa radio tracked individuals at Phu Luang Wildlife Sanctuary. Sex or Plastron length n Carapace length (cm) Body mass (kg) age class (cm) Male 5 25.8 ± 1.9 24.9 ± 2.5 2.5 ± 0.6 Female 5 27.1 ± 2.4 25.6 ± 2.8 3.0 ± 0.7 Juvenile 4 18.0 ± 1.3 17.8 ± 1.3 1.2 ± 0.2 n = number of tortoises with an average temperature during the wet, Analysis of the data.– The percentage of cold-dry and hot-dry seasons of 21.7 ± 0.3 active and inactive periods were estimated ºC, 15.3 ± 0.4 ºC and 22.8 ± 0.5 ºC, and categorized with respect to whether in respectively. The relative humidity at the the wet (May – October) or dry (November study site ranged from 60 – 100%. The – April) season. The difference in the average (± SE) relative humidity in the wet, percentage of active and inactive periods cold-dry and hot-dry seasons were 85.2 ± between the sexes, age classes and between 0.4%, 66.2 ± 0.4% and 78.6 ± 0.6%, the wet and dry seasons were analyzed using respectively. The average air temperature and ANOVA, accepting significance of relative humidity during the rainy and hot- differences at the p < 0.05 level. The mean dry seasons were both significantly higher annual temperature, mean relative humidity than those in the cold-dry season (ANOVA, and rainfall at the study site were obtained p < 0.05). from the nearby ranger weather station (1-3 The air temperature and relative km from the field site). In addition, the humidity were also recorded at the precise ambient temperature and relative humidity position where tortoises were located, so as were also recorded at the position where to allow the importance of any potential tortoises were located using a thermo- microhabitat-dependent variations to be hygrometer at 1 m above the forest floor. evaluated. The mean ambient temperature The differences in mean ambient and relative humidity for each activity are temperature and relative humidity between shown in Table 2. Active tortoises were adults and juveniles, and between the wet, found at ambient temperatures ranging from cold-dry and hot-dry seasons were analyzed 12.0 – 30.0 ºC (mean ± SE = 22.8 ± 0.14 ºC) using ANOVA using the SPSS 11.5 for and a relative humidity from 60 – 100% Windows software and accepting (mean ± SE = 82.2 ± 0.5%). However, large significance of differences at the p < 0.05 numbers of individuals were inactive level. (hiding) in the same period when the temperature and humidity ranged from 11.7 – 27.5 ºC (mean ± SE = 20.10 ± 0.13%) and RESULTS 60 – 100% (mean ± SE = 75.7 ± 0.4%), respectively. For all individuals, there was The air temperature, as obtained from no significant difference in the temperature nearby ranger weather station ranged from between each active behavior. However, 6.5 – 33.0 ºC (Mean ± SE = 19.9 ± 1.72 ºC) 42 basking tended to occur at the highest mean basking tended tooccuratthehighest mean TROPICAL NATURAL HISTORY 13(1), APRIL 2013 2013 APRIL 13(1), HISTORY NATURAL TROPICAL TABLE 2. Mean (± SE) air temperature and relative humidity (RH) during Manouria impressa activity in Phu Luang Wildlife Sanctuary (PLWS), Loei Province, Thailand from January 2010 to October 2011 inclusive.