Biological Conservation 182 (2015) 72–86

Contents lists available at ScienceDirect

Biological Conservation

journal homepage: www.elsevier .com/locate /b iocon

An assessment of South China tiger reintroduction potentialin Hupingshan and Houhe National Nature Reserves, China

http://dx.doi.org/10.1016/j.biocon.2014.10.0360006-3207/� 2014 The Authors. Published by Elsevier Ltd.This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/).

⇑ Corresponding author at: Environmental Studies Program, Colby College, 5358Mayflower Hill, Waterville, ME 04901 USA. Tel.: +1 207 859 5358; fax: +1 207 8595229.

E-mail address: pjnyhus@colby.edu (P.J. Nyhus).

Yiyuan Qin a,b, Philip J. Nyhus a,⇑, Courtney L. Larson a,g, Charles J.W. Carroll a,g, Jeff Muntifering c,Thomas D. Dahmer d, Lu Jun e, Ronald L. Tilson f

a Environmental Studies Program, Colby College, Waterville, ME 04901, USAbYale School of Forestry and Environmental Studies, New Haven, CT, USAcDepartment of Conservation, Minnesota Zoo, 13000 Zoo Blvd., Apple Valley, MN 55124, USAd Ecosystems, Ltd., Unit B13, 12/F Block 2, Yautong Ind. City, 17 KoFai Road, Yau Tong, Kowloon, Hong KongeNational Wildlife Research and Development Center, State Forestry Administration, People’s Republic of ChinafMinnesota Zoo Foundation, 13000 Zoo Blvd., Apple Valley, MN 55124, USAgGraduate Degree Program in Ecology, Colorado State University, Fort Collins, CO 80523, USA

a r t i c l e i n f o

Article history:Received 11 June 2014Received in revised form 20 October 2014Accepted 28 October 2014

Keywords:Panthera tigris amoyensisReintroductionRestorationConservationChinaHabitatWild boar Sus scrofaSika deer Cervus nipponGIS

a b s t r a c t

Human-caused biodiversity loss is a global problem, large carnivores are particularly threatened, and thetiger (Panthera tigris) is among the world’s most endangered large carnivores. The South China tiger(Panthera tigris amoyensis) is the most critically endangered tiger subspecies and is considered function-ally extinct in the wild. The government of China has expressed its intent to reintroduce a small popula-tion of South China tigers into a portion of their historic range as part of a larger goal to recover wild tigerpopulations in China. This would be the world’s first major tiger reintroduction program. A free-rangingpopulation of 15–20 tigers living in a minimum of 1000 km2 of habitat was identified as a target. Weassessed summer and winter habitat suitability of two critical prey species, wild boar (Sus scrofa) and Sikadeer (Cervus nippon), using GIS spatial models to evaluate the potential for tiger reintroduction in onelikely candidate site, the 1100 km2 Hupingshan–Houhe National Nature Reserve complex in Hunanand Hubei Provinces, China. Our preliminary analysis estimates that for wild boar, potential summerand winter habitat availability is 372–714 km2 and 256–690 km2, respectively, whereas for Sika deer,potential summer and winter habitat availability is 443–747 km2 and 257–734 km2, respectively. Ourmodel identifies potential priority areas for release and restoration of prey between 195 and 790 km2

with a carrying capacity of 596–2409 wild boar and 468–1929 Sika deer. Our analysis suggests thatHupingshan–Houhe could support a small population of 2–9 tigers at a density of 1.1–1.2 tigers/100 km2 following prey and habitat restorations. Thus, current habitat quality and area would fall shortof the target recovery goal. We identify major challenges facing a potential tiger reintroduction projectand conclude that restoring the habitat and prey base, addressing concerns of local people, and enhancingcoordination across park boundaries are significant challenges to meeting the broader goals of supportinga reintroduced wild tiger population. Tiger range states have committed to doubling the world’s wildtigers by 2022. The results of this study have implications for China’s commitment to this goal and forthe future of tiger and other large carnivore reintroduction efforts in Asia and globally.� 2014 The Authors. Published by Elsevier Ltd. This is an openaccess article under the CCBY license (http://

creativecommons.org/licenses/by/3.0/).

1. Introduction Marco et al., 2014; Ripple et al., 2014), and the tiger (Panthera

Human-caused biodiversity loss is a global problem thatextends across taxonomic groups and geographic regions (Dirzoet al., 2014). Large carnivores are particularly threatened (Di

tigris) is among the world’s most endangered large carnivores(Tilson and Nyhus, 2010).

The South China tiger (Panthera tigris amoyensis) is a tiger sub-species native to China (Nyhus, 2008) that is considered likelyextinct in the wild (Tilson et al., 2004). Numbering more than4000 as recently as the early 1950s, the South China tiger popula-tion in China suffered dramatic declines in the past century due togovernment eradication, habitat loss, unregulated hunting, andhuman encroachment into tiger habitat (IUCN, 2011; Tilson et al.,

Y. Qin et al. / Biological Conservation 182 (2015) 72–86 73

2004). It is now the most critically endangered of all tiger subspe-cies (IUCN, 2011).

The government of China, together with the leaders of tigerrange countries, recently declared a goal to double the world’s wildtiger population by 2022 (Global Tiger Summit, 2010;Wikramanayake et al., 2009). Due to the growing awareness ofthe importance of tiger reintroduction as one strategy to supporttiger recovery goals (Driscoll et al., 2012; Tilson et al., 2010), Chi-nese authorities and international organizations are seeking toidentify one or more existing protected areas of sufficient sizewithin the historical range of South China tigers to support wildtiger populations (State Forestry Administration of China, 2010;Tilson et al., 2010). This would be the world’s first large-scale rein-troduction of captive tigers back to the wild.

Predator reintroductions can enhance conservation by increas-ing abundance of the target species and other species that sharethese habitats (Deinet et al., 2013). Notable recent examples ofreintroductions that led to recovery of extirpated populationsinclude wolves in the western United States (Carroll et al., 2006)and Eurasian Lynx in Europe (Deinet et al., 2013). Effective reintro-ductions can have ecosystem-wide benefits by restoring historicspecies interactions, including trophic cascades (Ripple et al.,2014).

Since 1994, the Chinese Association of Zoological Gardens(CAZG) has been managing the remaining captive South Chinatigers (Wang et al., 1995). As of October 2011, there were 108 cap-tive South China tigers descended from the small founding popula-tion of six individuals captured between 1958 and 1960 (Tilsonet al., 1997; Traylor-Holzer et al., 2010). However, these remainingSouth China tigers face significant challenges to remain viable,including relatively low reproduction rates and low genetic varia-tion (Traylor-Holzer et al., 2010; Yin and Traylor-Holzer, 2011). Theorganization Save China’s Tigers, with the support of the State For-estry Administration of China (SFA), relocated five of these captivetigers to a private captive facility in South Africa to create a founderstock for possible future reintroduction of tigers back into the wildin China (Tilson et al., 2010). As of October 2011, there were 12 liv-ing individuals (four of the original tigers and eight of their off-spring) in South Africa (Yin and Traylor-Holzer, 2011).

International tiger experts and the IUCN Cat Specialist Grouphave proposed a minimum goal for a free-ranging South Chinatiger population by establishing at least three populations, eachconsisting of 15–20 tigers living in a minimum of 1000 km2 of nat-ural habitat within the historic range of the subspecies(Breitenmoser et al., 2006). Hupingshan–Houhe National NatureReserve (NNR) complex was identified as the largest and possiblythe most suitable location to support a small population of wildtigers (Tilson et al., 2004, 2010). With a total area of 1100 km2

the reserve complex is larger than 21 other areas identified aspotential high priority tiger landscapes across Asia (Sandersonet al., 2010). The most recent confirmed records of wild SouthChina tigers in this protected area complex were documented overtwo decades ago (Koehler, 1991), and protected area staff and vil-lagers also reported visual sightings and anecdotal evidence fromthe 1970s and the 1980s.

Large carnivores like tigers are often difficult to study in for-ested environments because of their low population densities,large home ranges, and cryptic behavior. This problem is magnifiedwhen the target species is extinct in the wild. Consequently, onemeans of addressing this is to examine prey populations. The liter-ature documents a strong, positive correlation between tiger abun-dance and prey availability (Karanth et al., 2004; Karanth and Stith,1999; Karanth and Sunquist, 1995; Sunquist, 2010) and highly cor-related activity patterns between tigers and tiger prey (Karanthand Sunquist, 2000; Sunquist, 1981). Therefore, an assessment ofhabitat suitability of tiger prey may serve as a reasonable proxy

to guide tiger restoration efforts, particularly since historic knowl-edge of tiger habitat use, movement patterns, and diets in this areais limited. Important tiger prey species include forest and grasslandungulates, ranging from small deer such as barking deer (Muntia-cus muntjak) (20 kg) and wild boar (Sus scrofa) (30–40 kg) to largeanimals like water buffalo (Bubalus bubalis) (160–400 kg) and sam-bar (Cervus unicolor) (185–260 kg) (Karanth et al., 2004; Smith andXie, 2008; Sunquist, 2010). Tiger predation is non-random; tigersselect for medium to large-size prey, and only switch to smallerprey when critical prey species are non-existent or at extremelylow densities (Biswas and Sankar, 2002; Karanth and Sunquist,1995; Sunquist, 2010, 1981).

In this study we used spatial Habitat Suitability Index (HSI)models to demonstrate how estimates of prey distribution andabundance can inform large carnivore restoration. Our specificobjectives were to identify: (1) the amount of suitable habitatavailable for tigers and two prey species in the Hupingshan–HouheNational Nature Reserve complex in China, (2) the approximateprey biomass the two reserves could support, and (3) the sizesand configurations of potential core areas that could support initialrelease and restoration of both tigers and their prey.

This effort was part of a larger goal to evaluate the feasibility ofa South China tiger reintroduction program. As field data for wildSouth China tiger and prey populations in Hupingshan–HouheNNR are essentially non-existent, our habitat suitability assess-ment was developed using Geographic Information Systems (GIS)based on literature reviews, preliminary field work, and expertopinion. Our spatial models provide a preliminary scientific assess-ment and reference for habitat evaluation, site selection, and con-servation planning for a potential South China tiger reintroductionin the Hupingshan–Houhe NNR complex. We conclude with a dis-cussion of key management issues that address potential ecologi-cal, landscape, genetic, and institutional challenges facing a tigerreintroduction program. The results of this study have implicationsfor other tiger and large carnivore reintroduction efforts in Asiaand globally.

2. Methods

2.1. Study area

The Hupingshan–Houhe National Nature Reserve complex con-sists of two adjacent NNRs located in south-central China (longi-tude 110�20 N – 110�590 N, latitude 29�580 E – 30�100 E).Hupingshan NNR is situated along the northern border of HunanProvince adjacent to Houhe NNR in southern Hubei Province(Fig. 1). Covering nearly 1100 km2, Hupingshan–Houhe is hometo some of China’s most threatened plant and animal species andoccurs in the historic range of the South China tiger (Dahmeret al., 2014; Houhe, 2004; Hupingshan, 2004).

Hupingshan–Houhe has an annual average temperature of 9.2 �C, annual average rainfall of 1900 mm, typically experiences hotand wet summers and cold winters, and supports subtropical ever-green and deciduous mixed forests (Houhe, 2004; Hupingshan,2004). Located in the transition region between the Guizhou Pla-teau and hilly areas in southeastern China, Hupingshan–Houhe istopographically heterogeneous, including high elevations, deepravines, and narrow valleys (Houhe, 2004; Hupingshan, 2004; Liet al., 2005; Liu and Pang, 2005; Qin et al., 2006).

The local human population within the protected area complexwas estimated to exceed 30,000 in 2002 (27.3 people/km2); how-ever, this estimate is likely unreliable because some residentswho emigrated from this area to urban areas are still registeredas living in this area (Houhe, 2004; Hupingshan, 2004). Thepopulation is characterized by a low annual per capita income

Fig. 1. Geographic features of Hupingshan–Houhe National Nature Reserve complex, China.

74 Y. Qin et al. / Biological Conservation 182 (2015) 72–86

and a high reliance on farming and livestock husbandry. Limitedindustry in the area includes coal and phosphate mining. Tourismis a small but growing economic activity. Key biodiversity threatshave been identified, including: forest fires, poaching (hunting isnot legal), livestock grazing, illegal logging, rapid and unregulateddevelopment from urban sprawl, road construction, mines, andfactories (Dahmer et al., 2014; Houhe, 2004; Hupingshan, 2004).

2.2. Habitat Suitability Index (HSI)

Widely used in ecological assessment and conservation plan-ning, HSI models incorporate expert opinion and/or ecologicalstudies to estimate habitat quality using factors, such as land coverand elevation, considered important for the presence or abundanceof a target species (Elith and Burgman, 2003; Kliskey et al., 1999;Lopez-Lopez et al., 2007; Luan et al., 2011; Store and Kangas,2001), especially when species distribution data are lacking(Burgman et al., 2001; Downs et al., 2008; Smith et al., 2007). Vari-ables can be scaled to a single standard to create a relative measureof habitat suitability that is comparable across locations (Brooks,1997; Elith and Burgman, 2003). Each variable in an HSI is repre-sented using a single suitability index (SI) linked by additive, mul-tiplicative, or logical functions that can best reflect relationshipsamong the variables (Burgman et al., 2001).

Since systematic field studies on ungulates in Hupingshan–Houhe are lacking, we used a comprehensive review of availableliterature and expert opinion to create HSI models for two tigerprey species. The models identify suitable habitat patches and esti-mate potential carrying capacity for the two species using variablesdeemed significant to their habitat requirements as well as prox-imity to human impacts. Parameters were estimated from researchon prey populations in other regions, while adjusting for climate,topography, and vegetation features of Hupingshan–Houhe.

2.2.1. Model prey species selectionForest and grassland ungulates make up the bulk of a tiger’s diet

(Miquelle et al., 1996; Smith and Xie, 2008; Sunquist, 2010). At

least nine potential prey species may have lived in Hupingshan–Houhe historically, and camera trap studies (Dahmer et al., 2004;Tilson et al., 2004) and a 2010 line transect survey (Lou et al.,2011) confirmed the presence of at least six prey species (Table 1).In addition to density, ungulate prey size and biomass are oftenkeys to survival and reproduction in wild tiger populations becausetigers select for large-size prey with a mean weight around 91.5 kg(Karanth and Stith, 1999; Karanth and Sunquist, 1995, 2000;Miquelle et al., 1996; Sunquist, 1981). Information on the size, con-servation status, and estimated current density of possible preyspecies is summarized in Table 1. Chinese serow (Capricornis mil-needwardsii), wild boar (Sus scrofa), and Sika deer (Cervus nippon)are among the relatively large prey species found in Hupingshan(Table 1). Wild boar and Sika deer were selected as model prey spe-cies based on expert opinion and lack of field data on Chineseserow (Tilson et al., 2008). Potential suitable habitat for thesetwo species was modeled in GIS to estimate potential prey densi-ties and thus possible tiger abundance.

2.2.2. Prey habitat and area requirements2.2.2.1. Wild boar. Wild boar are widely distributed across Europe,North Africa, Southeast Asia, Japan, and China, except for drydeserts and high plateaus (Leaper et al., 1999; Smith and Xie,2008). Wild boar are considered agricultural pests in some areas(Geisser and Reyer, 2004). Habitat use by wild boar is determinedin part by food availability, vegetation community, cover from pre-dators, slope, aspect, elevation, distance to water, and weatherconditions (Baber and Coblentz, 1986; Leaper et al., 1999).

Wild boar are omnivorous, but plant matter is predominant intheir diet, while crops and high energy food are highly preferred(Herrero et al., 2006; Leaper et al., 1999). Wild boar prefer butare not restricted to natural woodlands for shelter and food sources(Leaper et al., 1999; Smith and Xie, 2008). Pinewoods, mixedwoodland, scrub, and grasslands provide alternative foodresources. These habitat types, however, offer suboptimal shelter(Leaper et al., 1999; Thurfjell et al., 2009). Forest edges and spar-sely populated areas are also preferred because they provide more

Table 1Possible prey species historically present in the Hupingshan–Houhe National Nature Reserve Complex. A survey using line transects estimated current density and total numberfor some species in the Houhe NNR. VU – vulnerable, EN – endangered, LC – least concern.

Prey speciesa,d Mean weight (kg)a Conservation statusb Density (number) in Houhe NNRc

Chinese serow* (Capricornis milneedwardsii) 85–140 VU –Chinese water deer (Hydropotes inermis) 14–17 VU –Forest musk deer* (Moschus berezovskii) 6–9 EN –Long-tailed goral (Naemorhedus caudatus) 32–42 VU 2.1 ± 0.1/km2 (80 ± 4)Reeve’s muntjac (Muntiacus reevesi) 11–16 VU 5.6 ± 0.1/km2 (214 ± 6)Siberian roe (Capreolus pygargus) 20–40 VU –Sika deer (Cervus nippon) 40–150 EN –Tufted deer* (Elaphodus cephalophus) 15–28 VU 5.8 ± 0.2/km2 (222 ± 6)Wild boar* (Sus scrofa) 50–200 LC 7.9 ± 0.3/km2 (302 ± 11)

a Smith and Xie (2008).b Wang and Xie (2004), Smith and Xie (2008).c Line transect method, January–March, 2010 (Lou et al., 2011).d (*) Presence, camera trap study, 2001 (Dahmer et al., 2004).

Y. Qin et al. / Biological Conservation 182 (2015) 72–86 75

opportunities for food and shelter (Honda, 2009; Thurfjell et al.,2009).

Wild boar favor lower elevations and gentle slopes, while inwarm, dry regions they avoid south slopes where less grass andforbs grow (Baber and Coblentz, 1986; Honda, 2009). In Huping-shan–Houhe, wild boar were found at elevations as high as1400 m (Dahmer et al., 2004). They select areas with snow depthof less than 40–50 cm because snow hinders their movement(Honda, 2009) and prefer proximity to water for bathing, resting,reproduction, and rearing of young (Baber and Coblentz, 1986;Fernandez-Llario, 2004; Leaper et al., 1999; Thurfjell et al., 2009).Baber and Coblentz (1986) found in California, USA, that wild boaruse habitat within 330–370 m to water sources.

The home range of wild boar ranges from 0.7 to 24 km2 forfemales and 1.4–35 km2 for males, while density ranges from 2.6per km2 to 15 per km2. A summary of different density estimatesfor wild boar from various relevant study sites is listed in Table 2.Additionally, wild boar has been found to migrate from high(>1000 m) to low (<1000 m) elevation in winter (Andrzejewskiand Jezierski 1978; Singer et al., 1981).

2.2.2.2. Sika deer. Sika deer are widespread across eastern Chinaand also found in southeastern Siberia, Japan, and Korea (Smithand Xie, 2008). Habitat selection by Sika deer also depend on veg-etation type, food and water availability, shelter, and snow depth(Honda, 2009; Jiang and Li, 2009).

Sika deer forage in grass, shrub, shrub-meadow, and broad-leaved forests and feed on grass, browse, and occasionally on fruit(Jiang and Li, 2009; Smith and Xie, 2008; Yokoyama, 2009). Sikadeer will use agricultural fields adjacent to forest edges but avoiddensely populated urban areas (Honda, 2009; Miyashita et al.,2008).

In southern China, Sika deer usually live in mountainous habitatat low elevations (300–800 m), but can range to over 2000 m inwestern China (Jiang and Li, 2009; Koda et al., 2008; Koga and

Table 2Wild boar and Sika deer density estimates from selected locations.

Density (per km2) Location

Wild boar 2.6 Pench Nation4.4 Bardia Natio4.4–6.1 Sumatra, Ind7.9 Houhe NNR,15.0 South Carolin

Sika deer 0.5–0.7 Korea3.5–4.5 Ningguo, Chi8.6 Lazovsky res27.6 Taiwan50.0 Kinkazan Isla

Ono, 1994). The distribution of Sika deer is also limited by climate,particularly snow depth, as populations tend to descend to lowerelevations in winter before returning to higher elevations in spring(Igota et al., 2004; Smith and Xie, 2008). In a study in TaohonglingNature Reserve, Jiangxi Province, China, Sika deer showed no selec-tion for aspect, but preferred habitat with slopes between 15� and45� (Liu, 2007). Additionally, Sika deer prefer habitat where watersources are within 100–400 m (Jiang and Li, 2009).

The home range of Sika deer ranges from 0.2 to 0.6 km2 in BosoPeninsula, Japan, while density ranges from the historical record of3.5–4.5/km2 in southern China to 50/km2 in Northern Japan (Ito,2009; Jiang and Li, 2009; Miyashita et al., 2008, 2007; Takadaet al., 2002). A summary of density estimates for Sika deer fromvarious study sites is listed in Table 2. Home range, density, andhabitat selection of Sika deer are highly correlated with seasonali-ty. In the summer, the Sika deer home range is generally smallerand thus deer are more clustered than during the winter (Maejiet al., 1999; Miyashita et al., 2008).

2.2.3. Model specifications and data preparationHabitat requirement variables used in our models included:

land cover (LC), elevation (ELEV), slope (SLP), distance to water(DW), and distance to forest edge (DFE). Disturbance is representedby distance to areas of potential human impacts (DD), includingagriculture, roads, and urban centers. Because these HSI variablesare synergistic rather than cumulative, they were linked using amultiplicative function (Brown et al., 2000; Burgman et al., 2001;Williams et al., 2008). In summary, the HSI was a geometric meanof the six habitat variables using the following formula:

HSI ¼ ðDD� LC � ELEV � SLP � DW � DFEÞ1=6

Data were obtained from NASA’s Shuttle Radar TopographyMission (SRTM), Landsat satellite imagery, GIS data obtained fromChinese authorities, and data we digitized manually (Table 3).ArcGIS 10 (ESRI, Inc.) was used to process and combine thematic

References

al Park, India Biswas and Sankar (2002), Sunquist (2010)nal Park, Nepal Sunquist (2010)onesia O’Brien et al. (2003)China Lou et al. (2011)a, USA Saunders and McLeod (1999)

McCullough (2009)na Jiang and Li (2009)erve, Russia Voloshina and Myslenkov (2009)

Pei (2009)nd, Japan Ito (2009), McCullough (2009)

76 Y. Qin et al. / Biological Conservation 182 (2015) 72–86

layers. All layers were projected into Universal Transverse Merca-tor zone 49 N using the WGS84 datum, and all raster layers wereresampled to a cell size of 28.5 � 28.5 m2, the native size of theLandsat satellite imagery.

Where the original SRTM elevation data included significantdata gaps, we carried out our own interpolation by kriging, usingdigitized contour lines obtained from China’s State ForestryAdministration, and GPS elevation points. We derived slope fromthe original Digital Elevation Model (DEM) for all intact areasand used the modified SRTM elevation layer for the large interpo-lated areas. We created a Normalized Difference Vegetation Index(NDVI) using imagery from the Landsat Enhanced ThematicMapper (ETM+) sensor to assess photosynthetic activity (UnitedStates Geological Survey, 2008).

The land cover data layers were obtained from MacDonaldDettwiler and Associates (MDA) federal (MDA Federal, 2008) andare based on a 2000 Landsat ETM + image. Land cover classeslocated in the study area include deciduous forest, evergreen for-est, shrub/scrub, grassland, barren/minimal vegetation, urban/built-up, agriculture (general), agriculture (rice/paddy), wetland,and water. However, based on comparison to ground truthingGPS field data points from the Hupingshan–Houhe study area in2007, some areas originally classified as natural vegetation (e.g.,shrub/scrub, grassland, and barren/minimal vegetation) are actu-ally agricultural areas. Additionally, this classification schemefailed to identify agricultural areas alongside rivers and roads.

To resolve these overestimations of potential habitat, we usedNDVI values to differentiate natural vegetation from agriculture.We gathered ground control points in the field using GPS in 2007and compared the relative reflectance patterns of known agricul-tural areas from those with natural vegetation. The mean NDVIvalue of the agriculture points (0.102 ± 0.113) was significantly dif-ferent than that of the natural vegetation points (0.423 ± 0.083)(Mann–Whitney U-test, n = 52, p < .001). We then derived a thresh-old value of 0.275 to divide the shrub/scrub, grassland, and barren/minimal vegetation land cover classes into new agriculture orshrub/grassland classes, while keeping the original forest, urban/developed, wetland, water, and agriculture land cover classesintact. We also created 100 m buffers along both sides of all roadsand rivers, within which we used the above NDVI thresholds to

Table 3Sources for spatial data used in the habitat suitability analysis for wild boar and Sika dee

Model input Source

Elevation NASA Shuttle Radar Topography Mission (SRTMinterpolation from Chinese Academy of Forest

Slope Derived from elevationLand cover MDA Federal EarthSat GeoCover LC 2000Normalized Difference Vegetation

Index (NDVI)Landsat Enhanced Thematic Mapper (2002, 20

Roads Combination of GPS data from Nyhus (2008) a(2008)

Water Digitized from maps provided by State ForestrReserve boundaries Digitized from Hunan Hupingshan National Nat

National Nature Reserve (2004)

Table 4Definitions of suitability index values used in the habitat suitability analysis for wild boar

Suitability index Description of habitat use

0–2 Not suitable: little or no occurrence in field2.01–4 Least suitable: rare occurrence or very low4.01–6 Moderately suitable: low occurrence or de6.01–8 Highly suitable: average occurrence or den8.01–10 Most suitable: high density or relative abu

divide the forest, shrub/scrub, grassland, and barren/minimal veg-etation classes into either agriculture or shrub/grass classes.

All parameters were constructed on a scale from 0 to 10. Defini-tions of SI ranges were adapted from other HSI studies and stan-dardized (Brown et al., 2000; Burgman et al., 2001) (Table 4). SIvalue estimations used in this study linked habitat suitability topopulation abundance as well as fecundity and survival. A highSI value indicates high relative abundance or density and possiblyhigh fecundities and survivorships (Burgman et al., 2001).

To account for uncertainties in habitat requirement parameter-izations in the model, we created three scenarios (high – H, mid –M, and low – L) of suitability indices of habitat requirement foreach species (Burgman et al., 2001). We created one scenario fordistance to disturbance (DD). Since habitat selection of both spe-cies varies seasonally, particularly with elevation change, summer(S) and winter (W) scenarios were also constructed with differentelevation parameterizations to accommodate such potential varia-tions. Six HSI scenarios in total were created for each species: threeeach for summer and winter.

Categorical values were assigned for variables LC, ELEV, and SLP.A summary of suitability indices is presented for wild boar (Table 5)and for Sika deer (Table 6). We used continuous linear functionsrather than categorical values to convert DW, DFE, and DD intosuitability index values for both species. For DW, we expect thatdistances closer than 400 m are optimal, with suitability decliningat greater distances (Fig. 2). Functions used to convert DFE to SI val-ues were based on species requirements for foraging and shelter aswell as daily movement distance. Negative values for DFE repre-sent areas within the forest and positive values represent areasoutside the forest. We expect that suitability for prey specieswould be high to optimal in areas inside the forest and at the forestedge, and would decline steeply just outside the forest (<200 m), atwhich point suitability would continue to decline gradually (Fig. 3).We assumed a positive correlation between DD and suitabilityuntil 1000 m or greater, at which point habitat is optimal (Fig. 4).

Distances were obtained using euclidean distance. Agriculture,grassland/shrub, forest, and urban center land cover classes wereextracted from the land cover data. Inside and outside distancesto forest edges – borders between forest and shrub/grassland andagriculture – were derived by first generalizing each category from

r in Hupingshan–Houhe.

) Digital Elevation Model Version 3 (2006); elevation contour lines forry, provided by State Forestry Administration of China (2008)

08)

nd digitized data from maps provided by State Forestry Administration of China

y Administration of China (2008)ure Reserve Management Plan from the Administration of Hunan Hupingshan

and Sika deer in Hupingshan–Houhe National Nature Reserve complex.

studies; mortality may occur; active avoidance in field studiesdensity in field studiesnsity in field studiessity in field studiesndance in field studies; high growth potential; active preference in field studies

Table 5Suitability index values, assumptions, and relevant references for habitat type, slope, and elevation requirement for wild boar (Sus scrofa) in Hupingshan–Houhe National NatureReserve complex.

Variable Suitability index Assumption References

High Medium Low

Habitat type Forests are optimal habitat, providing food and shelter;agriculture lands and shrub/grassland provide alternative foodsources, but shelter is suboptimal

Baber and Coblentz (1986), Leaper et al. (1999), Fernandezet al. (2006), Herrero et al. (2006), Smith and Xie (2008),Honda (2009), Thurfjell et al. (2009)

Forest 10 10 10Agriculture 8 6 4Shrub/grassland

8 8 6

Urbanbuilt-up

0 0 0

Slope (�) Gentle slopes are preferred for the ease of movement Geisser and Reyer (2004), Honda (2009)0–15 10 10 1015–30 8 8 830–45 6 4 2>45 0 0 0

Summerelevation(m)

Lower elevations are preferred; presence was recorded in areasabove 1400 m; vegetation structure shifts around 1800 m;winter migration to low (<1000 m) elevation ranges occurs assnow depth restricts movement

Baber and Coblentz (1986), Leaper et al. (1999), Dahmeret al. (2004), Honda (2009)

<1500 10 10 101500–1800

8 6 4

>1800 6 4 2Winter

elevation(m)<1000 10 10 101000–1800 8 6 4>1800 6 4 2

Table 6Suitability index values, assumptions, and relevant references for habitat type, slope, and elevation requirement for Sika deer (Cervus nippon) in Hupingshan–Houhe NationalNature Reserve complex.

Variable Suitability index Assumption References

High Medium Low

Habitat type Forests and shrub/grass lands are both optimal habitat forfood and foraging; agricultural fields provide high amountsof plan material

Borkowski and Furubayashi (1998), Maeji et al. (1999), Kodaet al. (2008), Miyashita et al. (2008), Smith and Xie (2008),Honda (2009), Jiang and Li (2009), Pei (2009), Yokoyama(2009)

Forest 10 10 10Agriculture 8 6 4Shrub/grassland

10 10 10

Urbanbuilt-up

0 0 0

Slope (�) Gentler slope preferred, especially between 15� and 45� Maeji et al. (1999), Liu (2007), Honda (2009), Jiang and Li(2009)0–15 10 10 10

15–30 10 10 1030–45 8 6 4>45 0 0 0

Summerelevation(m)

Usually found in mountainous habitat at relatively lowelevation of 300–800 m; winter migration to lowerelevation occurs as snow depth restricts movement

Koga and Ono (1994), Maeji et al. (1999), Igota et al. (2004),Koda et al. (2008), Smith and Xie (2008), Jiang and Li (2009),Takatsuki (2009)

<1000 10 10 101000–1800 8 6 4>1800 6 4 2

Winterelevation(m)<800 10 10 10800–1500 8 6 4>1500 6 4 2

Y. Qin et al. / Biological Conservation 182 (2015) 72–86 77

land cover data and then combining reclassifications of the Euclid-ean distances. Finally, HSI results were reclassified into five catego-ries, ranging from 0–2 (not suitable) to 8.01–10 (most suitable) inaccordance with the SI definitions (Table 4).

2.2.4. Potential priority release sites and restoration areasTo identify core areas for possible prey release and restoration

in Hupingshan–Houhe we combined HSI values for both wild boar(HSIWB) and Sika deer (HSISD) to estimate total prey suitability

(HSIPrey). Six scenarios of HSIPrey were created using correspondingHSIWB and HSISD scenarios. To simplify the analysis we assumedcomplete niche differentiation and no density dependent mortalityfeedbacks between these two species. Both these assumptions maylead to an overestimation of suitable habitat and potential preydensity.

Studies have shown that the relative importance of prey in thetiger diet is correlated with prey biomass density and prey size(Table 7) (Biswas and Sankar, 2002; Miquelle et al., 1996; O’Brien

0

2

4

6

8

10

120

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

1600

1700

1800

1900

2000

2500

3000

Suita

bilit

y In

dex

Distance to water (m)

DW - High DW - Mid DW - Low

ab-H

b-M

b-L

c-H

c-M

c-L

Fig. 2. Functions used to convert distance to water (DW) to suitability index valuesfor wild boar and Sika deer, based on the species habitat requirement and dailymovement distance. Three scenarios of parameterization (high – H, mid – M, andlow – L) were created to account for uncertainty in the model. Different sectionsof the functions were given by (SI = suitability index, d = DW) (a) SI = 1 (d < 400);(b-H) SI = 10.5–1.25 � 10�3 d (400 < d < 2000); (b-M) SI = 11–2.5 � 10�3 d(400 < d < 2000); (b-L) SI = 11.5–3.75 � 10�3d (400 < d < 2000); (c-H) SI = 8(d > 2000); (c-M) SI = 6 (d > 2000); (c-L) SI = 4 (d > 2000) (Agetsuma et al., 2003;Baber and Coblentz, 1986; Jiang and Li, 2009; Leaper et al., 1999; Thurfjell et al.,2009).

0

2

4

6

8

10

12

-200

0-1

800

-160

0-1

400

-120

0-1

000

-800

-600

-400

-200 0

200

400

600

800

1000

1200

1400

1600

1800

2000

Suita

bilit

y In

dex

Distance to Forest Edge (m)DFE - High DFE - Mid DFE - Low

a-H

a-M

a-L

b-M

b-L

c

d

e

Fig. 3. Functions used to convert distance to forest edge (DFE) to suitability indexvalues for wild boar and Sika deer, based on the species habitat requirement anddaily movement distance. Three scenarios of parameterization (high – H, mid – M,and low – L) were created to account for uncertainty in the model. Negative valuesfor DFE represent areas within the forest and positive values represent areas outsidethe forest. Different sections of the functions were given by (SI = suitability index,d = DFE) (a-H) SI = 10 (d < 0); (a-M) SI = 8 (d < �500); (a-L) SI = 6 (d < �100); (b-M)SI = 10 + 4 � 10�4d (�500 < d < 0); (b-L) SI = 10 + 4 � 10�3 d (�100 < d < 0); (c)SI = 10–4 � 10�3 d (0 < d < 200); (d) SI = 2.25–1.25 � 10�3 d (200 < d < 1800); and(e) SI = 0 (d > 1800) (Fernandez et al., 2006; Geisser and Reyer, 2004; Leaper et al.,1999; Thurfjell et al., 2009; Yamada et al., 2003).

0

2

4

6

8

10

12

Suita

bilit

y In

dex

Distance to disturbance (m)

a

b

Fig. 4. Functions used to convert distance to disturbance (DD) to suitability indexvalues for wild boar and Sika deer. Different sections of the functions were given by(SI = suitability index, d = DD) (a) SI = 10�2 d (d < 1000) and (b) SI = 10 (d > 1000)(Thurfjell et al., 2009).

78 Y. Qin et al. / Biological Conservation 182 (2015) 72–86

et al., 2003; Sunquist, 2010). Population densities and meanweights of wild boar and Sika deer indicate a theoretically compa-rable biomass density of the two species, and thus similar potentialsignificance in tiger prey selection. Based on the above estimation,HSIPrey was calculated using the following formula to identify sitesthat meet the needs of both prey species:

HSIPrey ¼ ðHSIWB �HSISDÞ1=2

We identified potential priority areas by selecting habitatpatches with HSI values greater than 6 and larger than 1 km2 insize. We identified contiguous patches larger than 20 km2 aspotential priority release sites and smaller patches as priority res-toration areas.

2.2.5. Carrying capacity estimationHSI models typically assume a direct linear relationship with

carrying capacity, reflected in population density or biomass perunit area (Rand and Newman, 1998). To estimate the carryingcapacity of wild boar and Sika deer in Hupingshan–Houhe, we firstextrapolated the number of animals (n) each square pixel(812.25 m2) can potentially support based on its HSI value. Foreach pixel (i, j):

gij ¼ 0:1�HSI� d

where d is the average species density estimate (converted to ani-mals per pixel area), i and j reference a specific pixel. Because HSImodels were constructed based on a 0–10 scale, a coefficient of0.1 was applied to rescale the HSI to 0–1. Carrying capacity was cal-culated by summing the density values of each pixel in Huping-shan–Houhe:

K ¼X

nij

From the literature (Table 2), we calculated the mean densitiesfor wild boar and Sika deer after excluding the two highest densityestimates to reduce the risk of over-estimating potential prey den-sity. We used density estimates (d) of 4.6 wild boar per km2 and 3.6Sika deer per km2. We estimated carrying capacity for both speciesfor the entire Hupingshan–Houhe NNR complex as well as poten-tial priority areas.

3. Results

For each prey species, six different HSI scenarios showed arange of suitable habitats in Hupingshan–Houhe (Figs. 5 and 6).For wild boar, mean HSI values ranged from 5.00 to 5.99 for thesummer range, and 4.70 to 5.91 for the winter range (Table 8).Our model identified potential habitat (HSI > 6) for the summer

Table 7Ungulate species biomass density and relative biomass in tiger diet in India, Russian far east, and Indonesia.

Prey (mean weight,kg)

Biomass density(kg/km2)

Relative biomass in tiger diet(%)

References

Pench NP, IndiaWild boar (38) 98.4 7.7 Biswas and Sankar (2002), Sunquist (2010)Sambar (212) 1291.1 29.3Chital (55) 4441.3 39.6Muntjac (20) – 2.6

Sikhote-Alin, RussiaWild boar (125) – 24–29.5 Miquelle et al. (1996), Smith and Xie (2008), Takayoshi and Kousaku (2009),

Sunquist (2010)Sika deer (45) – 0.5Red deer (180) – 63.9Roe deer (30) – 0.9–6.3

Sumatra, IndonesiaWild boar (38) 190.8 –a O’Brien et al. (2003), Smith and Xie (2008), Sunquist (2010)Sambar (212) 206.3 –a

Muntjac (20) 67.7 –

a Tiger abundance is found to be significantly correlated with that of the wild boar (p < 0.05) and Sambar (p < 0.1).

Fig. 5. Summer and winter range Habitat Suitability Index (HSI) models of low to high habitat requirement estimations for wild boar in Hupingshan–Houhe National NatureReserve complex (HSI: 0–2, not suitable; 2.01–4, least suitable; 4.01–6, moderately suitable; 6.01–8, highly suitable; 8.01–10, most suitable).

Y. Qin et al. / Biological Conservation 182 (2015) 72–86 79

Fig. 6. Summer and winter range Habitat Suitability Index (HSI) models of low to high habitat requirement estimations for Sika deer in Hupingshan–Houhe National NatureReserve complex (HSI: 0–2, not suitable; 2.01–4, least suitable; 4.01–6, moderately suitable; 6.01–8, highly suitable; 8.01–10, most suitable).

Table 8Mean (standard deviation) and range of Habitat Suitability Index for wild boar and Sika deer in Hupingshan–Houhe National Nature Reserve complex under different scenarios.

High Mid Low

Summer Winter Summer Winter Summer Winter

Wild boar Mean 5.99 5.91 5.63 5.44 5.00 4.70(SD) (2.63) (2.59) (2.46) (2.37) (2.23) (2.09)Range 0–10 0–9.8 0–9.9 0–9.5 0–9.7 0–9.0

Sika deer Mean 6.13 6.04 5.69 5.55 5.11 4.91(SD) (2.68) (2.63) (2.46) (2.40) (2.22) (2.12)Range 0–9.9 0–9.9 0–9.5 0–9.5 0–9.0 0–9.0

80 Y. Qin et al. / Biological Conservation 182 (2015) 72–86

range with total sizes varying from 372 to 714 km2 (35–66% oftotal area in the reserve complex), while for the winter range,the extent of suitable habitat (HSI > 6) ranged from 256 to696 km2 (24–65% of total area) (Fig. 7A).

For Sika deer, mean HSI values ranged from 5.11 to 6.13 for thesummer range, and 4.91 to 6.04 for the winter range (Table 8). Ourmodel identified potential habitat (HSI > 6) for the summer range,

where the total areas ranged from 443 to 747 km2 (41–69%). Suit-able winter range for Sika deer also decreased relative to summerrange. The extent of suitable winter habitats (HSI > 6) ranged from257 to 734 km2 (24–68%). The percentages of habitat of differentqualities are summarized by the five HSI categories in Fig. 7B.

We identified a range of potential priority areas (HSI > 6,area > 1 km2) (Fig. 8). The extent of total potential priority area

(A)

(B)

0 - 2 2.01 - 4 4.01 - 6 6.01 - 8 8.01 - 10

HS

HW

MS

MW

LW

LS

HSI

Sce

nario

0 - 2 2.01 - 4 4.01 - 6 6.01 - 8 8.01 - 10

HS

HW

MS

MW

LW

LS

HSI

Scen

ario

Fig. 7. Percent of habitat in each Habitat Suitability Index (HSI) category, based ondifferent HSI scenarios for (A) wild boar and (B) Sika deer in Hupingshan–HouheNational Nature Reserve complex (scenario: high – H, mid – M, low – L, summer – S,and winter –W).

Y. Qin et al. / Biological Conservation 182 (2015) 72–86 81

ranged from 195 km2 (18%) (LW) to 709 km2 (66%) (HS) and theextent of potential priority release sites ranged from 93 km2 (9%)(LW) to 610 km2 (57%) (HS) (Table 9).

Carrying capacity of prey species in potential priority areas inHupingshan–Houhe was estimated to range (�25%, +25%) from596 (447, 745) (LW) to 2409 (1807, 3011) (HS) for wild boar andfrom 468 (351, 585) (LW) to 1929 (1447, 2411) (HS) for Sika deer(Table 10). For the entire Hupingshan–Houhe area, carrying capac-ity for wild boar was estimated to range from 2321 (LW) and 2960(HS) (Fig. 9A). Estimates of carrying capacity for Sika deer rangedfrom 1895 (LW) to 2370 (HS) (Fig. 9B).

4. Discussion

Our analysis identified potential priority areas, ranging from195 km2 (18%) (LW) to 709 km2 (66%) (HS), and current potentialpriority release sites for wild boar and Sika deer from 93 km2

(9%) (LW) to 610 km2 (57%) (HS) (Table 9). Although Huping-shan–Houhe is relatively large compared to other protected areasin south-central China (MacKinnon et al., 1996), the limited extentof connected suitable habitat could be a major challenge in meet-ing the tiger reintroduction goals proposed by international tigerexperts and the IUCN Cat Specialist Group.

One of the constraining factors is the complex topography inHupingshan–Houhe, where about 20% of the NNR is above1500 m and 38% of the area has a slope steeper than 30�. Addition-ally, the presence of farmland, towns, and roads in the NNR frag-ments and limits suitable habitat. To meet the needs of tigerswith large home ranges, major habitat restoration and expansionefforts, such as enhancement of corridors among habitat patchesand reforestation of degraded area, would be needed in Huping-shan–Houhe.

Tiger territory size is correlated with prey abundance. Increas-ing prey density is associated with decreasing tigress territory sizeup to a prey biomass of 2000 kg/km2, at which point female terri-tory size levels off (Karanth et al., 2004; Smirnov and Miquelle,1999; Sunquist, 2010, 1981). In the Russian Far East, tiger popula-tion densities are low (0.3–0.7 per 100 km2) due to the relativelyshort growing season and low primary production to support preyspecies (Karanth et al., 2004). In comparison, in India and Nepal,tiger population densities can exceed 10 tigers per 100 km2

(Karanth et al., 2004; Sunquist, 1981).Recent field surveys in Hupingshan–Houhe have reported low

wild boar abundance (Dahmer et al., 2004; Lou et al., 2011;Tilson et al., 2004). A recent survey of Sika deer found no evidenceof this endangered species in the wild in Hunan or Hubei provinces(Jiang and Li, 2009). This deteriorated prey base is a result of illegalharvesting, habitat conversion, and logging (Houhe, 2004;Hupingshan, 2004). Low prey biomass can lead to suppressed tigerreproduction and survivorship, and hence low tiger populationdensities (Karanth and Stith, 1999). It has been reported that tigersliving on a diet mainly consisting of small prey like barking deer(Muntiacus muntjak) may be unable to raise young (Sunquistet al., 1999). The recovery of an assemblage of sufficient largeungulate prey species is thus particularly important for tigerconservation.

In concurrence with field studies in other regions where tigerand prey densities have been studied, one ad hoc method for esti-mating tiger populations is to assume that an ‘‘average tiger”requires 50 ungulate prey animals annually, assuming these areungulate prey such as deer and wild boar (Karanth and Nichols,2010). Using an ecological model that predicts that each year tigerscrop about 10% of the available prey population, approximately500 medium-sized prey animals (i.e., wild boar and deer) areneeded to support one tiger (Karanth and Nichols, 2010; Karanthet al., 2004). Although the ultimate prey carrying capacity woulddepend on the nature of the actual species assemblage, consideringwild boar and Sika deer as potential critical prey species for rein-troduced tigers, our analysis suggest that the potential priorityareas could possibly support 2–9 tigers at a density of 1.1–1.2tigers per 100 km2 up to 1.5 tigers per 100 km2 assuming a 25%increase in prey abundance. The most optimistic of our carryingcapacity estimates for wild boar and Sika deer alone would thusfall short of meeting the minimum goal of supporting 15–20 tigers(Fig. 8). Prey population density could be higher if additional spe-cies are available, such as Chinese serow, or if prey species densi-ties were artificially enhanced through supplementation of stockfrom breeding facilities and with the provision of additional forage(Tilson et al., 2008). As a result, our estimates of potential tigerabundance are likely conservative.

Carrying capacities for wild boar and Sika deer could be con-strained by the fragmented habitat, potential interspecific compe-tition, and low quality habitat patches. Another constraint to theprey species is the limited extent of suitable lowland in Huping-shan–Houhe, as demonstrated in our models in which the area ofsuitable habitat decreased considerably for the winter scenariosfor wild boar and Sika deer.

The limited extent of suitable habitat and the current low preydensity are likely some of the most daunting challenges, but habi-

Fig. 8. Potential priority areas for prey release and restoration in Hupingshan–Houhe National Nature Reserve complex (HSI: 0–2, not suitable; 2.01–4, least suitable; 4.01–6,moderately suitable; 6.01–8, highly suitable; 8.01–10, most suitable).

Table 9Size (km2) of potential priority area for prey release and restoration in Hupingshan–Houhe National Nature Reserve complex under different scenarios.

High Mid Low

Summer Winter Summer Winter Summer Winter

Release 610 591 493 447 176 93Restoration 99 102 120 114 139 102Total 709 693 613 561 315 195

82 Y. Qin et al. / Biological Conservation 182 (2015) 72–86

tat and prey base restoration in Hupingshan–Houhe would alsolikely provide extended benefits to the conservation of biodiversityin the area. Hupingshan–Houhe is among the most biologicallydiverse forest ecosystems in China, home to at least ten globallythreatened plant and animal species, and is significant as one ofthe last large ecosystems within the historic range of the SouthChina tiger (Houhe, 2004; Hupingshan, 2004; Xie et al., 2004). Asa result, even if reintroduced tiger populations remained small,the act of further supporting wildlife protection in these areas,

including reducing illegal harvesting of timber and wildlife, couldhave significant positive impacts on the biological diversity inHupingshan–Houhe and regional biodiversity conservation goals.

4.1. Model limitations and potential improvements

Uncertainties and errors are inevitable in habitat suitabilityassessment models. Although HSI models are relatively transpar-ent, some commonly recognized uncertainties and errors in thesemodels include temporal variability, spatial variability, and sys-tematic and random measurement errors (Barry and Elith, 2006;Burgman et al., 2001; Storch, 2002).

Our prey models were constructed using information sourcedfrom published literature and expert knowledge. Although suitabil-ity index values were defined in the study, there is variability in theinformation on species habitat preferences. Given the differentvegetation types, climates, topographies, and other environmentalfactors of the various study locations, uncertainties in setting limitsand developing functions for suitability index estimations are

Table 10Carrying capacity (�25%, +25%) of wild boar and Sika deer in the potential priority area for prey release and restoration in Hupingshan–Houhe National Nature Reserve complexunder different scenarios. Density estimates of 4.6 wild boar per km2 and 3.6 Sika deer per km2 were used.

High Mid Low

Summer Winter Summer Winter Summer Winter

Wild boar Release 2087 2001 1615 1428 616 289�25% 1565 1501 1211 1071 462 217+25% 2609 2501 2019 1785 770 361Restoration 322 330 380 355 369 307�25% 242 248 285 266 277 230+25% 403 413 475 444 461 384Total 2409 2331 1995 1783 985 596�25% 1807 1748 1496 1337 739 447+25% 3011 2914 2494 2229 1231 745

Sika deer Release 1670 1601 1270 1135 478 223�25% 1253 1201 953 851 359 167+25% 2088 2001 1588 1419 598 279Restoration 259 266 302 283 290 245�25% 194 200 227 212 218 184+25% 324 333 378 354 363 306Total 1929 1867 1572 1418 768 468�25% 1447 1400 1179 1064 576 351+25% 2411 2334 1965 1773 960 585

(A)

(B)

0

500

1000

1500

2000

2500

3000

3500

H, S H, W M, S M, W L, S L, W

Car

ryin

g C

apac

ity

Scenario

2.01 – 4 4.01 – 6 6.01 – 8 8.01 – 10

0

500

1000

1500

2000

2500

H, S H, W M, S M, W L, S L, W

Car

ryin

g C

apac

ity

Scenario2.01 – 4 4.01 – 6 6.01 – 8 8.01 – 10

Fig. 9. Carrying capacity estimate of (A) wild boar and (B) Sika deer in Hupingshan–Houhe National Nature Reserve complex based on different Habitat SuitabilityIndex scenarios. Density estimates of 4.6 wild boar per km2 and 3.6 Sika deer perkm2 were used (scenario: high – H, mid – M, low – L, summer – S, and winter –W).

Y. Qin et al. / Biological Conservation 182 (2015) 72–86 83

inevitable. Limited availability of field data is another constraint.Some data, including snow depth, that may contribute to betterpredictions of species movement and habitat selection were notavailable for modeling. Improved data on the number and charac-teristics of people living within the reserves would also help bettermodel potential human–wildlife conflict for management.

We recognize that HSI models include variables that may becorrelated and the strength of the correlation varies (Burgmanet al., 2001), but without additional information, we assumed inde-pendence of variables used in our model. Errors in remote sensingand GIS technologies are also common. For example, misclassifi-cation can cause errors when classifying vegetation cover fromsatellite data (Shao and Wu, 2008). Finally, our HSI models didnot include species population dynamics, i.e., interspecific interac-tions and density-dependent effects such as social behaviors,which could potentially influence species distribution, movementsand ultimately carrying capacity.

To improve the reliability of the model, a study of species distri-bution and movement is well warranted. Field surveys will helpimprove and verify variable parameterization, selection, andassignment of relative importance as well as structure of the equa-tion that combines SI values into the HSI model.

4.2. Additional considerations and implications

Regardless of the underpinning limitations and uncertainties inthe model, suitable areas identified by our HSI models correspondwell with the occurrence of prey species from the 2001 cameratrap study, except for the records near major roads (Dahmeret al., 2004, 2014). Our study is not intended to provide a fine-grained analysis, but to evaluate the general suitability of the areaas the first attempt to analyze the potential for prey and tiger res-toration efforts in Hupingshan–Houhe. Our methods have implica-tions for other regions under considerations for tiger recoveryefforts where field data are limited.

According to the IUCN/SSC reintroduction guidelines, recoveryof prey populations at proposed release site(s) should be addressedbefore any reintroduction could be considered (IUCN/SSC, 1998).Given that tigers are capable of thriving in environments rangingfrom the temperate forests of the Russian far east to the junglesof Sumatra, Miquelle et al. (1996) have argued that tigers havefew ecological constraints that relate to specific habitat require-

84 Y. Qin et al. / Biological Conservation 182 (2015) 72–86

ments except for the direct influence from the abundance andcomposition of prey species. In addition, tigers have also shownconsiderable plasticity in predation behavior and relatively quickrecovery records given favorable conditions (Sunquist et al.,1999). Restoration of prey species could be enhanced from existingwild boar and deer farms in Hunan and Hubei Provinces (Tilsonet al., 2008).

Our HSI analysis and prey carrying capacity model estimatessuggest that the size and habitat quality of Hupingshan–Houheare not ideal compared to high priority tiger conservation land-scapes elsewhere in Asia (Sanderson et al., 2006). However, thereis adequate habitat that could support a small, highly managedpopulation of tigers if prey species were restored to their fullpotential and sufficient lowland areas were made available. Landexternal and adjacent to the two reserves is dominated by peopleand agriculture, limiting opportunities for reserve expansion orany meaningful corridors to other protected areas. A more nuanceddiscussion that evaluates additional benefits for both broader bio-diversity values and socio-political aspects that might result fromthe project’s implementation is thus well warranted.

Reintroduction of large carnivores is enormously controversialand carries a high risk of failure when the concerns of local peopleare not addressed (Breitenmoser et al., 2001; Jiménez, 2009). Forany reintroduction of tigers, a comprehensive assessment of theattitudes and needs of local people near possible release siteswould be necessary to ensure protection of villagers and their live-stock, and a reintroduced population of tigers (IUCN/SSC, 1998). Astrategy for meaningful local participation and for mitigating con-flicts between local people and reintroduced tigers would need tobe established. This is especially critical when reintroducing a spe-cies which may prey upon livestock or even people. Given thenumber of people in the area and limited suitable habitat, creatingbarriers such as fences would likely be necessary. Additional con-flict prevention and mitigation efforts, such as modifying livestockhusbandry practices and establishing effective compensation pro-grams, are used in other areas with high potential for tiger-humanconflict (Nyhus and Tilson, 2010).

Organizational issues can exert a significant influence on spe-cies recovery (Breitenmoser et al., 2001; Jiménez, 2009; Readinget al., 1997). Although Hupingshan and Houhe NNRs are spatiallycontiguous, they adjoin along the Hunan–Hubei provincial bound-ary and have separate, independent management structures: eachreserve has its own park office, directors, staff, and managementplan. Coordination among authorities across park and provincialboundaries is imperative to develop coherent management goalsand objectives for habitat restoration and expansion, prey baserecovery, management of human–wildlife conflict, and ultimatelythe survival of free-ranging tiger populations.

Finally, the population of captive South China tigers availablefor reintroduction is small and genetic diversity is a concern(Traylor-Holzer et al., 2010). At a minimum, intensive geneticand meta-population management in collaboration with theChinese Association of Zoological Gardens would be needed, andhybridization with other tiger subspecies might need to be consid-ered for long-term viability (Qin, 2012).

5. Conclusions

The global tiger conservation community and tiger range stateshave committed to doubling the world’s wild tiger population by2022. Reintroduction of captive tigers into the wild may be oneimportant step towards achieving this goal. The Government ofChina and international researchers have identified Hupingshanand Houhe National Nature Reserves as one potential release site.

Our analysis of potential prey and tiger suitability within the1100 km2 Hupingshan–Houhe NNR complex suggests that the hab-itat currently available is fragmented and dominated by uplandforests, steep slopes, agricultural lands, and substantial humanpopulations. At best, this area currently would support only a smallpopulation of 2–9 tigers and would require intensive managementto sustain tigers and prey and to mitigate human–wildlife conflict.A larger tiger population would likely be possible only if more areaand in particular more lowland habitat—now largely dominated bypeople and agriculture—was available to support a more robustprey base. At present, it is likely that too many people live withinthe reserve complex to justify a free-ranging population of tigers.

At the same time, the area likely represents the largest remain-ing protected area complex within the historic range of SouthChina tigers, and tigers were recorded in the area within the pastfour decades. Our analysis identifies potential priority restorationareas that would support modest tiger reintroduction and recoverygoals, assuming appropriate attention to the needs and safety oflocal communities as per IUCN reintroduction guidelines (IUCN/SSC, 1998). Conservation and restoration of former tiger habitatwould meet other biodiversity conservation objectives associatedwith the high biodiversity value currently represented withinthese reserves (Muntifering et al., 2010) and could help catalyzeconservation education and awareness programs and scientificresearch that further supports national and global biodiversityconservation objectives.

If free-ranging tigers are ever to return to south-central China,long-range planning is needed to identify areas that can in thefuture become sufficiently large, connected, and protected to main-tain an adequate prey base and to address the needs of local peopleto sustain a viable population of large carnivores. Large landscapeconservation efforts in Europe and North America have shown thisis possible over time, and China could become a conservation lea-der in developing this vision in Asia.

Acknowledgements

This research was made possible with support of and through aMemorandum of Understanding between the South China TigerAdvisory Office and the National Wildlife Research and Develop-ment Center, National Academy of Forestry, State Forestry Admin-istration (SFA) of the People’s Republic of China. Numerousindividuals and organizations supported earlier discussions or fieldwork, including: Wang Wei, Director of Forestry, SFA; WangWeisheng, Director, and Ruan Xiangdong, Deputy Director, WildlifeManagement Divisions, SFA; SFA staff and collaborators in Hubeiand Hunan Provinces, including Gui Xiaojie, Director of the NatureConservation Division, Forestry Department of Hunan Province;Wang Guoping, Director, Hunan Forestry Department; the parkdirectors at Hupingshan and Houhe National Nature Reservesand their staff, particularly Tian Shurong; and other collaboratorsincluding Hu Defu and Wang Bin. We thank Tara Harris, Depart-ment of Conservation, Minnesota Zoo, and Kevin Potts for theirideas and input. We appreciate the financial and logistical supportof the Minnesota Zoo Foundation, Colby College, Andrew W. Mel-lon Foundation, the Gary and JoAnn Fink Foundation, ColumbusZoo, Woodland Park Zoo, Ecosystems Ltd., Round River Conserva-tion Studies, International Business and Cooperation Agency ofthe Netherlands, and Gisbert Nollen of International ConsultancyEurope. We appreciate support for digitizing and other GIS workby: Rob Mehlich, Jr., Brendan Carrol, Carolyn Hunt, Caitlin Dufraine,Greg LaShoto, Katie Renwick, and Noah Teachey. We are particu-larly indebted to co-author and South China Tiger Advisory OfficeFounder and Director Dr. Ronald Tilson, who passed away unex-pectedly before this study was published.

Y. Qin et al. / Biological Conservation 182 (2015) 72–86 85

References

Agetsuma, N., Sugiura, H., Hill, D.A., Agetsuma-Yanagihara, Y., Tanaka, T., 2003.Population density and group composition of Japanese sika deer (Cervus nipponyakushimae) in an evergreen broad-leaved forest in Yakushima, southern Japan.Ecol. Res. 18, 475–483.

Andrzejewski, R., Jezierski, W., 1978. Management of a wild boar population and itseffects on commercial land. Acta Theriol. 23, 309–339.

Baber, D.W., Coblentz, B.E., 1986. Density, home range, habitat use, andreproduction in feral pigs on Santa Catalina Island. J. Mammal. 67, 512–525.

Barry, S., Elith, J., 2006. Error and uncertainty in habitat models. J. Appl. Ecol. 43,413–423.

Biswas, S., Sankar, K., 2002. Prey abundance and food habit of tigers (Pantheratigris tigris) in Pench National Park, Madhya Pradesh, India. J. Zool. 256,411–420.

Borkowski, J., Furubayashi, K., 1998. Home range size and habitat use in radio-collared female sika deer at high altitudes in the Tanzawa Mountains, Japan.Ann. Zool. Fenn. 35, 181–186.

Breitenmoser, U., Breitenmoser-Würsten, C., Carbyn, L.N., Funk, S.M., 2001.Assessment of carnivore reintroductions. In: Gittleman, J.L., Funk, S.M.,Macdonald, D.W., Wayne, R.K. (Eds.), Carnivore Conservation. CambridgeUniversity Press, Cambridge, U.K., pp. 241–281.

Breitenmoser, U., Tilson, R., Nyhus, P., 2006. Reintroduction of the Chinese tiger. CatNews 44, 15.

Brooks, R.P., 1997. Improving habitat suitability index models. Wildl. Soc. Bull. 25,163–167.

Brown, S., Buja, K., Jury, S., Monaco, M., Banner, A., 2000. Habitat suitability indexmodels for eight fish and invertebrate species in Casco and Sheepscot Bays,Maine. North Am. J. Fish. Manage. 20, 408–435.

Burgman, M.A., Breininger, D.R., Duncan, B.W., Ferson, S., 2001. Setting reliabilitybounds on habitat suitability indices. Ecol. Appl. 11, 70–78.

Carroll, C., Phillips, M.K., Lopez-Gonzalez, C.A., Schumaker, N.H., 2006. Definingrecovery goals and strategies for endangered species: the wolf as a case study.Bioscience 56, 25–37.

Dahmer, T.D., Xiaojie, G., Shurong, T., 2004. Camera-trapping to determine thestatus of South China Tiger in Hupingshan national nature reserve, Hunanprovince. In: The XIXTH International Congress of Zoology. China ZoologicalSociety, Beijing, China.

Dahmer, T.D., Xiaojie, G., Shurong, T., 2014. Camera-trapping for South China Tigerin Hupingshan National Nature Reserve, Hunan Province. Chinese J. Wildl. 35,19–25.

Deinet, S., Ieronymidou, C., McRae, L., Burfield, I.J., Foppen, R.P., Collen, B., Böhm, M.,2013. Wildlife Comback in Europe: the recovery of selected mammal and birdspecies. Final report to Rewilding Europe by ZSL, BirdLife International and theEuropean Bird Census Council. ZSL, London, UK.

Di Marco, M., Boitani, L., Mallon, D., Hoffmann, M., Iacucci, A., Meijaard, E., Visconti,P., Schipper, J., Rondinini, C., 2014. A retrospective evaluation of the globaldecline of carnivores and ungulates. Conserv. Biol. 28, 1109–1118.

Dirzo, R., Young, H.S., Galetti, M., Ceballos, G., Isaac, N.J.B., Collen, B., 2014.Defaunation in the anthropocene. Science 345, 401–406.

Downs, J.A., Gates, R.J., Murray, A.T., 2008. Estimating carrying capacity for sandhillcranes using habitat suitability and spatial optimization models. Ecol. Model.214, 284–292.

Driscoll, C.A., Chestin, I., Jungius, H.O.P., Darman, Y.A., Dinerstein, E., Seidensticker,J., Sanderson, J., Christie, S., Luo, S.J., Shrestha, M., Zhuravlev, Y., Uphyrkina, O.,Jhala, Y., Yadav, A.S., Pikunov, D.G., Yamaguchi, N., Wildt, D.E., Smith, J.L.D.,Marker, L., Nyhus, P.J., Tilson, R., Macdonald, D.W., O’Brien, S., 2012. A postulatefor tiger recovery: the case of the caspian tiger. J. Threatened Taxa 4, 2637–2643.

Elith, J., Burgman, M.A., 2003. Habitat models for population viability analysis. In:Brigham, C.A., Schwartz, M.W. (Eds.), Population Viability Analysis in Plants.Springer-Verlag, Berlin, Germany.

Fernandez-Llario, P., 2004. Environmental correlates of nest site selection by wildboar Sus scrofa. Acta Theriol. 49, 383–392.

Fernandez, N., Kramer-Schadt, S., Thulke, H.H., 2006. Viability and risk assessmentin species restoration: planning reintroductions for the wild boar, a potentialdisease reservoir. Ecol. Soc. 11, 17.

Geisser, H., Reyer, H.U., 2004. Efficacy of hunting, feeding, and fencing to reducecrop damage by wild boars. J. Wildlife Manage. 68, 939–946.

Global Tiger Summit, 2010. The St. Petersburg Declaration on Tiger Conservation, St.Petersburg, Russia.

Herrero, J., Garcia-Serrano, A., Couto, S., Ortuno, V.M., Garcia-Gonzalez, R., 2006.Diet of wild boar Sus scrofa L. and crop damage in an intensive agroecosystem.Eur. J. Wildl. Res. 52, 245–250.

Honda, T., 2009. Environmental factors affecting the distribution of the wild boar,sika deer, Asiatic black bear and Japanese macaque in central Japan, withimplications for human-wildlife conflict. Mammal Study 34, 107–116.

Houhe, 2004. Houhe National Nature Reserve Management Plan. Hubei WufengHouhe National Nature Reserve Administration, Hubei Province, P.R. China.

Hupingshan, 2004. Hupingshan National Nature Reserve Management Plan. HunanHupingshan National Nature Reserve Administration, Hunan Province, P.R.China.

Igota, H., Sakuragi, M., Uno, H., Kaji, K., Kaneko, M., Akamatsu, R., Maekawa, K., 2004.Seasonal migration patterns of female sika deer in eastern Hokkaido, Japan.Ecol. Res. 19, 169–178.

Ito, T.Y., 2009. Plants and plant communities on Kinkazan Island, Northern Japan, inrelation to sika deer herbivory. In: McCullough, D.R., Takatsuki, S., Kaji, K. (Eds.),Sika Deer: Biology and Management of Native and Introduced Populations.Springer, Japan, pp. 125–143.

IUCN, 2011. IUCN Red List of Threatened Species. IUCN, Gland, Switzerland.IUCN/SSC, 1998. Guidelines for Reintroduction. IUCN/SSC Reintroduction Specialist

Group, Gland, Switzerland.Jiang, Z.-G., Li, C.-W., 2009. Sika deer in mainland China. In: McCullough, D.R.,

Takatsuki, S., Kaji, K. (Eds.), Sika Deer: Biology and Management of Native andIntroduced Populations. Springer, Japan, pp. 521–539.

Jiménez, I., 2009. Non-biological aspects to be considered in endangered speciesrecovery programmes. In: Vargas, A., Breitenmoser, C., Breitenmoser, U. (Eds.),Iberian Lynx Ex situ Conservation: An Interdisciplinary Approach. FundaciónBiodiversidad, Madrid, Spain.

Karanth, K.U., Nichols, J.D., 2010. Non-invasive survey methods for assessing tigerpopulations. In: Tilson, R., Nyhus, P.J. (Eds.), Tigers of the World: The Science,Politics, and Conservation of Panthera tigris, second ed. Elsevier, San Diego, pp.143–161.

Karanth, K.U., Nichols, J.D., Kumar, N.S., Link, W.A., Hines, J.E., 2004. Tigers and theirprey: predicting carnivore densities from prey abundance. PNAS 101, 4854–4858.

Karanth, K.U., Stith, B.M., 1999. Prey depletion as a critical determinant of tigerpopulations. In: Seidensticker, J., Christie, S., Jackson, P. (Eds.), Riding the Tiger:Tiger Conservation in Human-dominated Landscapes. Cambridge UniversityPress, Cambridge, U.K., pp. 104–113.

Karanth, K.U., Sunquist, M.E., 1995. Prey selection by tiger, leopard and dhole intropical forests. J. Anim. Ecol. 64, 439–450.

Karanth, K.U., Sunquist, M.E., 2000. Behavioural correlates of predation by tiger(Panthera tigris), leopard (Panthera pardus) and dhole (Cuon alpinus) inNagarahole, India. J. Zool. 250, 255–265.

Kliskey, A., Lofroth, E., Thompson, W., Brown, S., Schreier, H., 1999. Simulating andevaluating alternative resource-use strategies using GIS-based habitatsuitability indices. Landscape Urban Plan. 45, 163–175.

Koda, R., Noma, N., Tsujino, R., Umeki, K., Fujita, N., 2008. Effects of sika deer (Cervusnippon yakushimae) population growth on saplings in an evergreen broad-leaved forest. For. Ecol. Manage. 256, 431–437.

Koehler, G., 1991. Survey of remaining wild population of South China tigers. WWFProject 4152/China Final Project Report. Unpublished Report. WWF,Washington, D.C.

Koga, T., Ono, Y., 1994. Sexual differences in foraging behavior of Sika deer, Cervusnippon. J. Mammal. 75, 129–135.

Leaper, R., Massei, G., Gorman, M.L., Aspinall, R., 1999. The feasibility ofreintroducing Wild Boar (Sus scrofa) to Scotland. Mammal Rev. 29, 239–259.

Li, Z., Wang, L., Huang, H., Tang, D., Pu, Y., Zheng, C., 2005. Situation and strategy ofbiodiversity conservation in the Houhe National Nature Reserve, vol. 23. ChinaWuhan Botanical Research, Hubei Province, pp. 592–600.

Liu, J., 2007. Food and habitat selection by sika deer (Cervus nippon kopschi) andhabitat improvement in the Taohongling Nature Reserve, Jiangxi. Institute ofZoology, Chinese Academy of Sciences, Beijing, China.

Liu, Y., Pang, X., 2005. Eco – tourism resource inventory and evaluation of HouheNational Nature Reserve in Hubei. Forest Inventory Plan. 30, 64–68.

Lopez-Lopez, P., Garcia-Ripolles, C., Soutullo, A., Cadahia, L., Urios, V., 2007.Identifying potentially suitable nesting habitat for golden eagles applied to‘important bird areas’ design. Anim. Conserv. 10, 208–218.

Lou, D., Yu, B.C., Liu, Y., Gao, E.H., Gong, M.H., 2011. Feasibility Study Report onSouth China Tiger Reintroduction Project. Houhe National Nature Reserve,Hubei Province (2011–2013) Survey and Planning Institute of State ForestryAdministration and Houhe National Nature Reserve Administration.

Luan, X., Qu, Y., Li, D., Liu, S., Wang, X., Wu, B., Zhu, C., 2011. Habitat evaluation ofwild Amur tiger (Panthera tigris altaica) and conservation priority setting innorth-eastern China. J. Environ. Manage. 92, 31–42.

MacKinnon, J., Sha, M., Cheung, C., Carey, G., Ziang, Z., Melville, D., 1996. ABiodiversity Review of China. World Wide Fund for Nature International ChinaProgramme, Hong Kong.

Maeji, I., Yokoyama, S., Shibata, E.i., 1999. Population density and range use of sikadeer, Cervus nippon, onMt. Ohdaigahara, central Japan. J. Forest Res. 4, 235–239.

McCullough, D.R., 2009. Sika Deer in Korea and Vietnam. In: McCullough, D.R.,Takatsuki, S., Kaji, K. (Eds.), Sika Deer: Biology and Management of Native andIntroduced Populations. Springer, Japan, pp. 541–548.

MDA Federal, 2008. EarthSat GeoCover LC <http://www.mdafederal.com/geocover/geocoverlc/>.

Miquelle, D.G., Smirnov, E.N., Quigley, H.G., Hornocker, M.G., Nikolaev, I.G.,Matyushkin, E.N., 1996. Food habits of Amur tigers in the Sikhote-AlinZapovednik and the Russian far east, and implications for conservation. J.Wildlife Res. 1, 138–147.

Miyashita, T., Suzuki, M., Ando, D., Fujita, G., Ochiai, K., Asada, M., 2008. Forest edgecreates small-scale variation in reproductive rate of sika deer. Popul. Ecol. 50,111–120.

Miyashita, T., Suzuki, M., Takada, M., Fujita, G., Ochiai, K., Asad, M., 2007. Landscapestructure affects food quality of sika deer (Cervus nippon) evidenced by fecalnitrogen levels. Popul. Ecol. 49, 185–190.

Muntifering, J.R., Nyhus, P.J., Tilson, R., Soulé, M.E., 2010. Tiger restoration andbiodiversity refugia in Asia: ‘Picking Up’ the pieces. In: Tilson, R., Nyhus, P.J.(Eds.), Tigers of the World: The Science, Politics, and Conservation of Pantheratigris, Second ed. Elsevier/Academic Press, San Diego, pp. 453–456.

86 Y. Qin et al. / Biological Conservation 182 (2015) 72–86

Nyhus, P., 2008. Panthera tigris ssp. amoyensis (South China Tiger). In: The IUCN RedList of Threatened Species. IUCN, Gland, Switzerland.

Nyhus, P.J., Tilson, R., 2010. Panthera tigris vs Homo sapiens: conflict, coexistence, orextinction. In: Tilson, R., Nyhus, P.J. (Eds.), Tigers of the World: The Biology,Politics, and Conservation of Panthera tigris, Second ed. Elsevier/AcademicPress, San Diego, CA, pp. 125–141.

O’Brien, T.G., Kinnaird, M.F., Wibisono, H.T., 2003. Crouching tigers, hidden prey:Sumatran tiger and prey populations in a tropical forest landscape. Anim.Conserv. 6, 131–139.

Pei, K.J.-C., 2009. The Present Status of the Re-introduced Sika Deer in KentingNational Park, Southern Taiwan. In: McCullough, D.R., Takatsuki, S., Kaji, K.(Eds.), Sika Deer: Biology and Management of Native and IntroducedPopulations. Springer, Japan, pp. 561–570.

Qin, Y., 2012. Reintroduction of the South China Tiger: lessons, assessments, andimplications. Honors Thesis. Colby College, Waterville, Maine, USA.

Qin, Z., Wang, L., Zhao, T., Tian, S., 2006. 壶瓶山国家级自然保护区的资源特点及其评价

[Resource characteristics and evaluation of hupingshan national naturereserve]. J. West China Forestry Sci. p. 3.

Rand, G.M., Newman, J.R., 1998. The applicability of habitat evaluationmethodologies in ecological risk assessment. Hum. Ecol. Risk Assessment 4,905–929.

Reading, R.P., Clark, T.W., Griffith, B., 1997. The influence of valuational andorganizational considerations on the success of rare species translocations. Biol.Conserv. 79, 217–225.

Ripple, W.J., Estes, J.A., Beschta, R.L., Wilmers, C.C., Ritchie, E.G., Hebblewhite, M.,Berger, J., Elmhagen, B., Letnic, M., Nelson, M.P., Schmitz, O.J., Smith, D.W.,Wallach, A.D., Wirsing, A.J., 2014. Status and ecological effects of the world’slargest carnivores. Science, 343.

Sanderson, E., Forrest, J., Loucks, C., Ginsberg, J., Dinerstein, E., Seidensticker, J.,Leimgruber, P., Songer, M., Hedlauff, A., O’Brien, T., Bryja, G., Klenzendorf, S.,WiKramanayake, E., 2006. Setting priorities for the conservation and recovery ofwild tigers: 2005–2015. WCS, WWF, Smithsonian, and NFWF-STF, New York, N.Y. and Washington, D.C.

Sanderson, E.W., Forrest, J., Loucks, C., Ginsberg, J., Dinerstein, E., Seidensticker, J.,Leimgruber, P., Songer, M., Heydlauff, A., O’Brien, T., Bryja, G., Klenzendorf, S.,Wikramanayake, E., 2010. Setting priorities for tiger conservation: 2005–2015.In: Tilson, R., Nyhus, P.J. (Eds.), Tigers of the World: The Science, Politics, andConservation of Panthera tigris, Second ed. Elsevier/Academic Press, San Diego,pp. 141–163.

Saunders, G., McLeod, S., 1999. Predicting home range size from the body mass orpopulation densities of feral pigs, Sus scrofa (Artiodactyla : Suidae). Austral JEcol 24, 538–543.

Shao, G.F., Wu, J.G., 2008. On the accuracy of landscape pattern analysis usingremote sensing data. Landscape Ecol. 23, 505–511.

Singer, F.J., Otto, D.K., Tipton, A.R., Hable, C.P., 1981. Home ranges, movements, andhabitat use of European wild boar in Tennessee. J. Wildlife Manage. 45, 343–353.

Smirnov, E.N., Miquelle, D.G., 1999. Population dynamics of the Amur tiger inSikhote-Alin state biosphere reserve. In: Seidensticker, J., Christie, S., Jackson, P.(Eds.), Riding the Tiger: Tiger Conservation in Human-Dominated Landscapes.Cambridge University Press, Cambridge, United Kingdom, pp. 61–70.

Smith, A.T., Xie, Y., 2008. A Guide to the Mammals of China. Princeton UniversityPress, Princeton, NJ.

Smith, C.S., Howes, A.L., Price, B., McAlpine, C.A., 2007. Using a Bayesian beliefnetwork to predict suitable habitat of an endangered mammal – the Julia creekdunnart (Sminthopsis douglasi). Biol. Conserv. 139, 333–347.

State Forestry Administration of China, 2010. Action Plan for Restoration of WildTiger Population in China.

Storch, I., 2002. On spatial resolution in habitat models: can small-scale foreststructure explain capercaillie numbers? Conserv. Ecol. 6, 6 <http://www.consecol.org/vol6iss1/art6>.

Store, R., Kangas, J., 2001. Integrating spatial multi-criteria evaluation and expertknowledge for GIS-based habitat suitability modelling. Landscape Urban Plan.55, 79–93.

Sunquist, M., 2010. What is a tiger? ecology and behavior. In: Tilson, R., Nyhus, P.J.(Eds.), Tigers of the World: The Science, Politics, and Conservation of Pantheratigris, Second ed. Elsevier/Academic Press, San Diego, pp. 19–33.

Sunquist, M., Karanth, K.U., Sunquist, F., 1999. Ecology, behavior and resilience ofthe tiger and its conservation needs. In: Seidensticker, J., Christie, S., Jackson, P.(Eds.), Riding the Tiger: Tiger Conservation in Human-Dominated Landscapes.Cambridge University Press, Cambridge, U.K., pp. 5–18.

Sunquist, M.E., 1981. The social organization of tigers (Panthera tigris) in RoyalChitawan National Park, Nepal. Smithsonian Institution Press, Washington, D.C..

Takada, M., Asada, M., Miyashita, T., 2002. Cross-habitat foraging by sika deerinfluences plant community structure in a forest-grassland landscape.Oecologia 133, 389–394.

Takatsuki, S., 2009. A 20-Year History of Sika Deer Management in the Mt. GoyoArea, Northern Honshu. In: McCullough, D.R., Takatsuki, S., Kaji, K. (Eds.), SikaDeer: Biology and Management of Native and Introduced Populations. Springer,Japan, pp. 365–373.

Takayoshi, M., Kousaku, S., 2009. Nutritional Physiology of Wild and DomesticatedJapanese Sika Deer. In: McCullough, D.R., Takatsuki, S., Kaji, K. (Eds.), Sika Deer:Biology and Management of Native and Introduced Populations. Springer, Japan,pp. 61–82.

Thurfjell, H., Ball, J.P., Ahlen, P.A., Kornacher, P., Dettki, H., Sjoberg, K., 2009. Habitatuse and spatial patterns of wild boar Sus scrofa (L.): agricultural fields and edges.Eur. J. Wildlife Res. 55, 517–523.

Tilson, R., Defu, H., Muntifering, J., Nyhus, P.J., 2004. Dramatic decline of wild SouthChina tigers: field survey of priority tiger reserves. Oryx 38, 40–47.

Tilson, R., Nyhus, P., Harris, T., Fisher, T., 2008. Trip report: prey management, fencesand finances: Changsha (Hunan Province) and Wuhan (Hubei Province), P.R.China. Minnesota Zoo and Colby College.

Tilson, R., Nyhus, P., Muntifering, J.R., 2010. Yin and yang of tiger conservation inChina. In: Tilson, R., Nyhus, P.J. (Eds.), Tigers of the World: The Science, Politics,and Conservation of Panthera tigris, Second ed. Elsevier/Academic Press, SanDiego, pp. 439–451.

Tilson, R., Nyhus, P.J. (Eds.), 2010. Tigers of the World: The Biology, Politics, andConservation of Panthera tigris, Second ed. Elsevier, San Diego.

Tilson, R., Traylor-Holzer, K., Jiang, Q.M., 1997. The decline and impendingextinction of the South China tiger. Oryx 31, 243–252.

Traylor-Holzer, K., Zhong, X., Yuzhong, Y., 2010. The struggle to save the last southChina tigers. In: Tilson, R., Nyhus, P.J. (Eds.), Tigers of the World: The Science,Politics, and Conservation of Panthera tigris, Second ed. Academic Press/Elsevier, San Diego, CA, pp. 457–462.

United States Geological Survey, 2008. Band Designations Page last modified22.08.08; visited 04.09.08 <http://eros.usgs.gov/products/satellite/band.html>.

Voloshina, I.V., Myslenkov, A.I., 2009. Sika Deer Distribution Changes at theNorthern Extent of Their Range in the Sikhote-Alin Mountains of the RussianFar East. In: McCullough, D.R., Takatsuki, S., Kaji, K. (Eds.), Sika Deer: Biologyand Management of Native and Introduced Populations. Springer, Japan, pp.501–519.

Wang, S., Xie, Y., 2004. China Species Red List. Higher Education Press, Beijing,China.

Wang, M., Tilson, R., Traylor-Holzer, K., Manansang, J., Seal, U., 1995. South ChinaTiger Studbook Analysis and Masterplan. Minnesota Zoo, Apple Valley, MN.

Wikramanayake, E., Lieberman, S., Nihan, P., Benn, J., 2009. Tigers alive! savingtigers in the wild. In: Strategic Plan 2010–2015. World Wildlife Fund for Nature,Washington, DC.

Williams, N.S.G., Hahs, A.K., Morgan, J.W., 2008. A dispersal-constrained habitatsuitability model for predicting invasion of alpine vegetation. Ecol. Appl. 18,347–359.

Xie, Y., Mackinnon, J., Li, D., 2004. Study on biogeographical divisions of China.Biodivers. Conserv. 13, 1391–1417.

Yamada, K., Elith, J., McCarthy, M., Zerger, A., 2003. Eliciting and integrating expertknowledge for wildlife habitat modelling. Ecol. Model. 165, 251–264.

Yin, Y., Traylor-Holzer, K., 2011. CAZG South China Tiger Studbook Analysis.Chongqing Zoo, Chongqing, China.

Yokoyama, M., 2009. Biology of sika deer in hyogo: characteristics of reproduction,food habits, growth, and condition. In: McCullough, D.R., Takatsuki, S., Kaji, K.(Eds.), Sika Deer: Biology and Management of Native and IntroducedPopulations. Springer, Japan, pp. 193–205.