Habitat of the Vulnerable Formosan Sambar Deer Rusa Unicolor Swinhoii in Taiwan

Habitat of the Vulnerable Formosan sambar deer Rusa unicolor swinhoii in Taiwan S HIH-CHING Y EN,YING W ANG and H ENG-YOU O U Abstract The sambar deer Rusa unicolor is categorized as & Ehrlich, 2002). Furthermore, as a result of more effective Vulnerable on the IUCN Red List because of continuous hunting techniques, overexploitation has become the most population decline across its native range. In Taiwan the important threat after habitat destruction for the survival of Formosan sambar deer R. unicolor swinhoii is listed as a large herbivores (Groom, 2006). Consequently many protected species under the Wildlife Conservation Act ungulates in Asia are confined to protected areas and are because of human overexploitation. However, its population limited to small populations (Baskin & Danell, 2003). Thus status remains unclear. We used presence and absence data conservation actions are required to ensure the long-term from line transect and camera-trap surveys to identify key survival of these animals. habitat variables and to map potential habitats available to One of the most important factors in successfully this subspecies in Taiwan. We applied five habitat- managing and conserving a species is accurate identification suitability models: logistic regression, discriminant analysis, of its distribution (Boitani et al., 2008). To accomplish this ecological-niche factor analysis, genetic algorithm for rule- we must understand how environmental factors determine set production, and maximum entropy. We then combined the habitat of a species. Advances in habitat suitability the results of all five models into an ensemble-forecasting modelling techniques combined with geographical infor- model to facilitate a more robust prediction. This model mation systems provide accessible tools for identify- 2 indicated the existence of 7,865 km of suitable habitat for ing suitable habitats and predicting potential species the sambar deer. Distance from roads and elevation were distribution (Anderson et al., 2003; Gavashelishvili & identified as the most important environmental variables Javakhishvili, 2010). However, predictions of species for habitat suitability, and deer preferred areas far from distribution can vary significantly with different modelling roads and . 1,500 m altitude. The results predicted that techniques (Thuiller et al., 2004; Pearson et al., 2006) and it suitable deer habitat is mainly located in Taiwan’s Central is difficult to select the most realistic. Araújo & New (2007) Mountain Range and Xue Mountain Range, with c. 70% advocated the use of ensemble forecasting, which often of this suitable habitat in protected areas. However, the generates a more robust prediction than a single model habitat predicted to be suitable is in five areas separated (Araújo & New, 2007; Marmion et al., 2009; Thuiller et al., by mountain highways. We recommend that deer habitats 2009; Oppel et al., 2012). close to the highways should be monitored for the future The sambar deer Rusa unicolor is a large ungulate establishment of corridors between Formosan sambar deer distributed throughout South and South-East Asia (Leslie, sub-populations. 2011). Although this species became a pest after introduction to countries such as Australia (Gormley et al., 2011), Keywords Habitat suitability, predicted distribution, populations in its native range have declined, with many Rusa unicolor, sambar deer local-level extinctions as a result of extensive hunting and habitat loss (Timmins et al., 2008). It remains regionally abundant only in well-secured (i.e. protected or remote) Introduction areas. The sambar deer is categorized as Vulnerable on the IUCN Red List (Timmins et al., 2008). Although some arge wild herbivores are primary consumers that countries, such as Thailand, have banned hunting, the play an important role in ecosystems and provide a L recovery rate of sambar deer populations remains slow, substantial economic resource for many communities. requiring further evaluation of population distributions and However, human land use has caused fragmentation, dynamics (Steinmetz et al., 2009). degradation and loss of habitat for these species (Ceballos The Formosan sambar deer R. unicolor swinhoii is a subspecies endemic to Taiwan (Wilson & Reeder, 2005). It is categorized as a rare and valuable species in the List of SHIH-CHING YEN and YING WANG Department of Life Science, National Taiwan Protected Species in Taiwan (Forest Bureau of Taiwan, Normal University, Taipei, Taiwan 2009). In the decades before the 1990s there was a decline in HENG-YOU OU (Corresponding author) Institute of Ecology and Evolutionary the number and geographical distribution of the Formosan Biology, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 106, fl Taiwan. E-mail [email protected] sambar deer in Taiwan, re ecting similar trends in other ’ 1990 Received 23 April 2012. Revision requested 10 October 2012. areas of the sambar deer s range. However, in the mid s Accepted 10 October 2012. First published online 17 October 2013. there was a slight increase in Formosan sambar deer © 2013 Fauna & Flora International, Oryx, 48(2), 232–240 doi:10.1017/S0030605312001378 Downloaded from https://www.cambridge.org/core. IP address: 170.106.40.139, on 02 Oct 2021 at 07:12:07, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605312001378 Habitat of Vulnerable sambar in Taiwan 233 (a) (b) Yangmingshan National Park 25°N Chatianshan Nature Reserve Shei-Pa National Park Xue Mountain Range 24°N Taroko National Park Yushan National Park Yuli Wildlife Refuge FIG. 1 Map of Taiwan, Ali Mountain Range showing (a) the locations and elevations of the mountain Yu Mountain Range Guanshan Wildlife Refuge 23°N Elevation (m) C e n t r a l M o u n t a i n R a n g e ranges and (b) the locations of Coastal Mountain Range3501 - 3952 3001 - 3000 protected areas and recorded 2501 - 3000 Absence grid locations of Formosan sambar 2001 - 2500 1501 - 2000 Presence grid deer in Taiwan. Location data 1001 - 1500 fi 501 - 1000 Protected area were collected from eld 0 - 500 surveys (2008–2012) and 22°N 0 25 50 100 km 120°E 121°E 122°E Kenting National Park assimilated from previous studies (2002–2007). populations in Taiwan (Timmins et al., 2008). Surveys human settlements. There are 89 protected areas, covering a 2 indicated that Formosan sambar deer were mainly dis- total of c. 6,951 km (Fig. 1b). The climate is tropical marine, tributed in the Central Mountain Range (Wang et al., with warm and humid weather (mean annual temperature 2002; Fig. 1a), although the surveys were limited in effort in the lowlands is c. 23 °C; mean annual precipitation is relative to the size of the island. 2,500 mm; Central Weather Bureau of Taiwan, 2013). Several studies in India (Porwal et al., 1996; Kushwaha However, the weather is cold in the high mountains, where it et al., 2004) and Australia (Forsyth et al., 2009; Gormley snows during winter. Snow cover duration is short, from et al., 2011) have described the distribution patterns and several days to 2 months, depending on height and latitude. habitat selection of sambar deer. In Taiwan suitable habitat for the species lies above 1,000 m (Wang et al., 2002). In addition, the climate and vegetation types are subject to Methods variation along the elevation gradient and are different to those of other countries. Furthermore, Taiwan has high Data collection population and road densities, which have caused extensive habitat destruction. Therefore investigations of habitat The locational data were primarily assimilated from our selection by sambar deer in highly disturbed areas are field observations of sambar deer (2008–2012). Data from required. Our aims in the study reported here were to field studies at other sites were also included (Pei et al., 2002, evaluate habitat suitability and to map the distribution 2003; Pei, 2004; Wu & Shi, 2006; Lee et al., 2007; Wu & Yao, pattern of Formosan sambar deer throughout Taiwan. We 2007; C.Y. Lin, pers. comm.). Although the collection of use the results to identify the most important sites for the multiple datasets using different techniques prevented a management of this threatened subspecies. standardized evaluation, it allowed the incorporation of data from many sites and environments. Two different survey techniques were used. The first involved the use of line Study area transects to obtain data on deer presence. Absence data were not collected because it is difficult to confirm the absence of 2 The 35,801 km island of Taiwan lies off the south-eastern a species in such surveys. Transect lines were located on coast of mainland China. Topography is high and steep, hiking and hunting trails. At each study site we surveyed with five mountain ranges (Fig. 1a), and altitudes of several transect lines, to cover the various environments of 0–3,952 m. The vegetation changes with altitude, from that site. We recorded 1,582 coordinates of sambar deer broadleaf forests to coniferous forests and then to scrub tracks and signs (i.e. sightings, vocalizations, scats, foot- (Su, 1992). Two-thirds of the island is covered by forested prints, tree rubbing and shed antlers) using a global mountains. Most of the coastal plains are occupied by positioning system. The second technique involved the use © 2013 Fauna & Flora International, Oryx, 48(2), 232–240 Downloaded from https://www.cambridge.org/core. IP address: 170.106.40.139, on 02 Oct 2021 at 07:12:07, subject to the Cambridge

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