Response of the red fox to expansion of human

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Sep 26, 2015 - dogs in the rural mountainous landscape of the Trans-. Himalayan Spiti ... to being cash-based and market oriented in the last two to three decades ... free of human settlement) in spite of systematic search across the pasture. ... There is no report of red fox preying on livestock species in the study area, and ...
Eur J Wildl Res DOI 10.1007/s10344-015-0967-8

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Response of the red fox to expansion of human habitation in the Trans-Himalayan mountains Abhishek Ghoshal 1 & Yash Veer Bhatnagar 1,2 & Charudutt Mishra 1,2 & Kulbhushansingh Suryawanshi 1,2

Received: 6 December 2014 / Revised: 26 September 2015 / Accepted: 29 September 2015 # Springer-Verlag Berlin Heidelberg 2015

Abstract Habitat modification through rural and urban expansions negatively impacts most wildlife species. However, anthropogenic food sources in habitations can benefit certain species. The red fox Vulpes vulpes can exploit anthropogenic food, but human subsidies sometimes also sustain populations of its potential competitor, the free-ranging dog Canis familiaris. As human habitations expand, populations of free-ranging dog are increasing in many areas, with unknown effects on wild commensal species such as the red fox. We examined occurrence and diet of red fox along a gradient of village size in a rural mountainous landscape of the Indian Trans-Himalaya. Diet analyses suggest substantial use of anthropogenic food (livestock and garbage) by red fox. Contribution of livestock and garbage to diet of red fox declined and increased, respectively, with increasing village size. Red fox occurrence did not show a clear relationship with village size. Red fox occurrence showed weak positive relationships with density of free-ranging dog and garbage availability, respectively, while density of free-ranging dog showed strong positive relationships with village size and garbage availability, respectively. We highlight the potential conservation concern arising from the strong positive association between density of free-ranging dog and village size. Electronic supplementary material The online version of this article (doi:10.1007/s10344-015-0967-8) contains supplementary material, which is available to authorized users. * Abhishek Ghoshal [email protected] 1

Nature Conservation Foundation, 3076/5, IV Cross, Gokulam Park, Mysore 570002, Karnataka, India

2

Snow Leopard Trust, 4649 Sunnyside Av. North, Suite 325, Seattle, WA 98103, USA

Keywords Vulpes vulpes . Canis familiaris . Carnivore . Human subsidies . Commensal . Diet . Dog

Introduction Urban and rural expansion over the past few decades has led to marked landscape-level modifications that have significantly altered the structure and function of ecosystems in large parts of the world (Randa and Yunger 2006). Along with habitat loss, habitat modification has often had negative impacts on species diversity as it often accompanies habitat fragmentation (Saunders et al. 1991), introduction of exotic species (Myers et al. 2000; Pimentel et al. 2005; Raghavan et al. 2008) and habitat degradation (McKinney 2002; Pickett et al. 2001; Wilcove et al. 1998). Urban and rural expansion, however, is often accompanied by increased availability of food sources (e.g., garbage dumps) for some wild species that may benefit from human modification of landscapes (Blair 1996; Newsome et al. 2015; Randa and Yunger 2006). Garbage dumps and other human wastes attract and serve as food sources for several carnivores such as spotted hyena Crocuta (Abay et al. 2011), dingo Canis lupus dingo (Newsome et al. 2013), coyote Canis latrans (Ditchkoff et al. 2006), red fox Vulpes (Gloor et al. 2001) and golden jackal Canis aureus (Macdonald 1979) and for the even larger ones such as black bear Ursus americanus (Rogers et al. 1976), grizzly bear Ursus arctos (Blanchard 1987), and polar bear Ursus maritimus (Stempniewicz 2006; Dyck and Romberg 2007). There is an increasing recognition of the significance of human-modified landscapes as habitats for several wild species (Elfström et al. 2012; Randa and Yunger 2006). Yet, seldom have common species associated with human settlements been the focus of conservation or monitoring programmes

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(Gaston 2008, 2010; Gaston and Fuller 2007, 2008; Redford et al. 2013). Recent drastic population declines of several common species such as the house sparrow Passer domesticus (Robinson et al. 2005), vulture Gyps spp. (Green et al. 2004) and golden jackal Canis aureus (Pillay et al. 2011) have highlighted a need to understand the responses of common species towards changing urban and rural environment. The red fox is a widespread generalist mesocarnivore found both in natural and human-dominated landscapes in large parts of the world (Bidlack et al. 2006; Gloor et al. 2001; Macdonald and Reynolds 2008). It uses a wide array of locally available resources, including garbage in urban and rural areas (Aryal et al. 2010; Contesse et al. 2004; Doncaster et al. 1990; Mateos et al. 2007). In India, red fox is a native species, distributed across the Himalayan and Trans-Himalayan ranges in the north and the desert region in the north-west. In the Trans-Himalayan Spiti Valley, rapid increase in tourism in the last two decades has led to a tenfold increase in the number of restaurants and hotels in the larger villages and townships that have considerably contributed to garbage generation (USL 2011). While this has the potential to benefit the red fox, there has also been an increase in the population of free-ranging dog Canis familiaris in the region to an extent that they pose a threat to livestock and wildlife (Suryawanshi et al. 2013; USL 2011). In this paper, we examine the response of the red fox towards these changes. We expected red foxes to be influenced positively by village size and negatively by the density of free-ranging dog. Red foxes were expected to benefit from increasing availability of food as village size increases. However, larger villages were also expected to support higher dog populations. We expected free-ranging dogs to affect red foxes negatively as dogs are both their potential competitors and predators (Brassine and Parker 2011; Mitchell and Banks 2005). Here, we examine how occurrence and diet of the red fox change along a gradient of village size and density of free-ranging dogs in the rural mountainous landscape of the TransHimalayan Spiti Valley.

Methodology Study area The study was carried out in the Spiti subdivision (32.16 N; 77.66 E, 32.66 N; 77.66 E), Lahaul and Spiti, Himachal Pradesh, India. It is a Trans-Himalayan high-elevation (3700–4200) landscape. The vegetation is classified as ‘dry alpine steppe’ (Champion and Seth 1968). Primary livelihood of local people is agro-pastoralism (Mishra 2001). The local economy of the Spiti Valley has undergone a rapid shift from subsistence, barter-based system to being cash-based and market oriented in the last two to

three decades (Mishra 2000). We selected 10 villages, representing a wide gradient of village size from seven houses in Tashigang to 229 houses in Kaza (Fig. 1). We also sampled a representative pasture, Chomaling (hereafter Chomaling, 32.34 N; 78.02 E), which was devoid of houses and therefore largely free of garbage, ca. 2 km away from and ca. 300 m higher than Kibber village. Sampling was done during winter over 2 months of February–March 2011. Red fox occurrence We used the red fox track density as an index of fox occurrence. Red fox tracks were identified following the ‘12-5-3 Rule’ (Fuhrmann 2002)—tracks with a stride distance of less than 12 in., a straddle of fewer than 5 in., and track length of less than 3 in.. This was first tested for precision in the field by recording track dimensions immediately after a red fox sighting. Measurements were taken at a minimum of 3 points on the same set of tracks. We sampled number of red fox tracks in 14 plots of 5 m× 5 m laid on snow in each village. Uniform sampling effort was made in all the villages. Each village and Chomaling was sampled twice, separated by about 1 month (Online Resource 1). Data were pooled from the two sampling occasions and ‘tracks per hectare (ha)’ was calculated for each village as a measure of fox occurrence. Variables potentially influencing red fox occurrence Information on village size (number of houses) was collected from local administrative office. Garbage dump dimensions (length and width) were measured in all villages. For assessing the density of free-ranging dog (number of free-ranging dog per hectare), block count (Sutherland 1996) method was used (Online Resource 1). Diet of red fox To examine the dependence of red fox on anthropogenic food items, we assessed its diet using microhistogical analyses. Red fox scat samples were collected opportunistically in and around the immediate vicinity of each village. Presence of long pointed tips, red fox tracks near the scat sample, small size and presence of vegetable matter were used to distinguish fox scats from those of dog. Any feces that were relatively larger or around dog signs were not collected. Scat samples were sun dried and later fragmented manually to separate the content. Scats were not encountered in Chomaling (the site free of human settlement) in spite of systematic search across the pasture. We collected 225 red fox scat samples. Adequacy of sample size was assessed at individual village level through species/food item accumulation curves (Online Resource 2).

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Fig. 1 The study area in the Trans-Himalayan Spiti Valley, Himachal Pradesh, India, is a subdivision of the Lahaul and Spiti District. The surveyed villages are shown on the map. Inset (left): Location of

Himachal Pradesh in northern India; inset (right): location of the Spiti subdivision in Himachal Pradesh

Hair were separated from the samples for identification of mammalian prey species (Mukherjee et al. 1994) by comparing with reference samples collected in the field and reference photographs (Oli 1993). Shape, colour, texture, characteristics of medulla and cuticle of hair were used for the identification of species. There is no report of red fox preying on livestock species in the study area, and livestock was available to red foxes in the form of abandoned carcasses and leftover meat from the villagers. Hence, we combined livestock and garbage occurrence in the diet and considered them together as the anthropogenic food items.

insects, small mammals, wild herbivores and birds (Online Resource 1). Anthropogenic items constituted the highest proportion in diet, occurring in 83.6 % of the scat samples, followed by vegetation matter (71.6 %), insects (19 %), small mammals (15 %), wild herbivores (2.2 %) and birds (1.8 %). Hair analysis showed that among livestock species, goat Capra hircus contributed to the diet the most (35.8 %), followed by sheep Ovis aries (28.9 %), cow Bos indicus (10.1 %), yak Bos grunniens (2.8 %), donkey Equus asinus (2.2 %) and horse E. caballus (0.7 %). Of the wild herbivores, blue sheep Pseudois nayaur constituted only 1.4 %, while ibex Capra sibirica did not occur in the scats. Wild ungulates were recorded in the diet in only 2 of the 11 study villages. Voles Alticola spp. and other rodents constituted 15.1 and 1.6 %, respectively. Of the total hair samples, 1.5 % remained unidentified. Use of anthropogenic food (livestock and garbage) by foxes did not show a clear association with village size (Kendall’s tau=− 0.30; P=0.24). The contribution of livestock to the diet of red fox declined from 61 % in smaller villages to 13.6 % in the larger ones (Kendall’s tau=− 0.44, P=0.07) (Fig. 2), while the contribution of garbage in red fox diet showed a weak increase with village size (Kendall’s tau =0.45, P = 0.07)

Results Diet of red fox Garbage availability had a strong and positive association with village size (Kendall’s tau=0.81, P