KEYWORDS
Habitat utilization; Himalayan marmot; Human activities; Burrow feature; Burrow site selection
1 ǀ INTRODUCTION
Nature is increasingly affected by human disturbances around the world. With the human population growing, more than 80% of global land surfaces are affected by human activities (Sanderson et al., 2002). Besides affecting environments on a macro level, human activities also affect aspects of wildlife interaction with those environments such as distribution, population dynamics, and ability to survive in changing conditions (Trombulak & Frissell, 2000; UNEP, 2001; Gül et al., 2013).
Human activities generally exert direct and indirect negative effects on animals. Direct and fatal disturbances include both illegal poaching and legal hunting (Ménard et al., 2014; Brockman et al., 2020), road killing by vehicles (Richini-Pereira et al., 2008), which will kill victims directly, and sometimes result in a population decline of some species (Rija et al., 2020), and damage regional community structure (Trombulak & Frissell, 2000; Clark et al., 2016). Indirect and less fatal effects include habitat degradation, traffic noise, light pollution, or hunting derived competition between different species, which will trigger reduced reproductive output and decline in body condition of affected animals (Safina & Burger, 1983; Primack, 2008; French et al. , 2011; Hellgren & Polnaszek, 2011; Muhly et al., 2011; Webber et al., 2013), and, may result in local extinction at population level due to habitat removal (Griffin et al., 2007; Imperio et al., 2013). Furthermore, species that accompany humans, such as domestic dogs (Canis lupus familiaris ), also negatively impact the survival of wild animals (Mainini et al., 1993; Mori, 2017). On the other hand, some animals benefit from human activity. For instance, some prey species experience reduced mortality because humans drive their predators and/or competitors away from human-dominated habitats (Hebblewhite et al., 2005; Muhly et al., 2011; Lambe, 2016). Some species have improved feeding efficiency due to human activities (Xiang et al., 2011; Marty et al., 2019) or gain higher reproductive success due to better nesting conditions in areas with human activity (O’Donnell & Denicola, 2006), benefits that can directly promote the population growth.
Different animals have greater or lesser chances to survive in the face of different human disturbances (Imperio et al., 2013; Ménard et al., 2014; Lambe, 2016; Amphibiaweb, 2021) depending upon the type and degree of human activities (Griffin et al., 2007; Ménard et al., 2014), as well as the species’ ability to adapt to disturbance (Griffin et al., 2007; Muhly et al., 2011; Webber et al., 2013; Yang et al., 2019). Possible outcomes for these populations include either coexistence with humans or active avoidance of humans (Magle et al., 2005; Griffin et al., 2007; Braczkowski et al., 2018), or local extinction (Imperio et al., 2013; Amphibiaweb, 2021). Generally, small-bodied species may survive more easily in areas of intense human activity than bigger species and even benefit from the altered landscape. For example, red foxes (Vulpes vulpes ) occur at higher densities in the city than in rural areas because of the absence of coyotes (Canis latrans ), and some urban-living macaques (Macaca spp.) obtain better food relative to their rural populations (Lambe, 2016, Marty et al., 2019). On the other hand, large-bodied species tend to avoid habitats impacted by humans regardless of whether humans actively kill them (Paudel & Kindlmann, 2012; Macedo et al., 2018; Klaassen & Broekhuis, 2018). Though in rare cases populations forced to share habitats with humans, such as leopards (Panthera pardus ) in Mumbai, India, develop particular strategies like adjusting their daily time budget and prey selection to survive (Braczkowski et al., 2018). Additionally, some animal species adopted different strategies and have different destinies under different human disturbances, depending on the type and intensity of disturbances (Murdoch et al., 2016; Austin & Ramp, 2019; Jahren et al., 2019).
Especially, highly residential species with limited migration ability and low phenotypic plasticity are at the greatest risk of going locally extinct due to human disturbance whether they are big or small bodied. For example, the Yunnan lake newt (Cynops wolterstorffi ) (Amphibiaweb, 2021), Alpine rock ptarmigans (Imperio et al., 2013), and Asiatic lion (Panthera leo persica ) as well as south China tiger (P. tigris amoyensis ) who cannot avoid human disturbances in the form of roads or log through migration (Tilson et al., 2004; Jhala et al., 2019), the population decline and local extinctions are common. Nevertheless, some certain other residential species like some rodents (Maher, 2009; Harris & Munshi‐South, 2017), primates (Marty et al., 2019), and some carnivores like some red fox populations (Lambe, 2016; Jahren et al., 2019) are better able to adapt and survive in human-dominated habitats and gain a higher population density relative to their rural congeners. To deal with different human influences suffered, animals have adopted multiple survival strategies such as adjusting time rhythm (Poudel et al., 2015a), allocating more time to vigilance (Griffin et al., 2007; Poudel et al., 2015b), or using habitats farther away from human activity (Paudel & Kindlmann, 2011; Macedo et al., 2018; Pita et al., 2020). In terms of the effect of human activities on habitat utilization for animals that can survive disturbances that are not directly fatal, certain strategies were adopted to deal with different disturbances. For example, Vancouver Island marmot (Marmota vancouverensis ) may build additional burrows for shelter when threatened (Blumstein et al. , 2001), bamboo rat (Rhizomys sinensis ) selectively construct their burrows away from roads (Yuan et al., 2017), or some grassland species like Alpine marmot (M. marmota ) select regions with large stones to allow better vigilance (Borgo, 2003). Furthermore, species like Alpine marmot and some waterbirds can behaviorally reduce flight initiation distance to optimize their fitness by the accustomed to nonfatal human activities (Louis & Le Berre, 2000; Thibault et al., 2020; Feng & Liang, 2020).
Marmots (Marmota spp.) are large, residential ground-dwelling and burrowing squirrels with relatively weak ability to disperse and high philopatry (Griffin et al. , 2007; Armitage et al., 2011), forcing them to continue exploiting habitats disturbed by humans (Neuhaus & Mainini, 1998). Previous studies illustrated that Himalayan marmots (M.himalayana ) deal with grazing disturbances by adjusting their daily time rhythm (Poudel et al., 2015a) and changing the time allocated to feeding and vigilance behavior (Poudel et al., 2015b). In comparison, some other marmot species like yellow-bellied marmots (M. flaviventris ) and Olympic marmots (M. olympus ) also adjust the time spent on feeding and vigilance, and further, they also adjust their flight initiation distance when disturbed by different human activities (Griffin et al. , 2007, Li et al., 2011). On the contrary, the flight initiation distance of woodchuck (M. monax ) did not vary along a rural-urban gradient, but the home range of the species decreased with the increasing urbanization (Watson, 2009). Besides, the study on Alpine marmots indicated that they have learned to tolerate hikers that pass by (Mainini et al., 1992).
Himalayan marmots are mainly distributed across the Qinghai-Tibetan Plateau (Shrestha, 2016). Some regional populations suffer persistent disturbance from human activities such as extermination campaigns to prevent disease, which subsequently has caused them to increase their reproductive rate in the years following these population reductions (Huang et al., 1986; Wang et al., 1986). Other populations are indirectly disturbed by domesticated yaks and goats, resulting in changes to time spent feeding and greater feeding efficiency (Poudel et al., 2015a; Poudel et al., 2015b). The effects of persistent, but not fatal, human disturbances on the Himalayan marmot requires further investigation. For example, the impact of motor vehicle activity on their habitat utilization, population dynamics and behavioral plasticity is still under explored (Kitchen et al., 1999; Klaassen & Broekhuis, 2018; Edwards et al., 2019); Whittington et al., 2019). In the present study, we recorded and compared the patterns of habitat utilization of three Himalayan marmot populations sharing the same habitat type, but suffering different levels of anthropogenic disturbance around a Tibetan village in the Zoige wetland (Guo et al., 2020), to explore the effects of human activity on this species’ behavior and discover changes that might improve their survival. Because reproductive pairs of the marmot will dig some temporary burrows as a shelter when threatened (Blumstein et al. , 2001) and human did not alter their habitat selection in the region (Guo et al., 2020). We predict that: (1) the distance between burrows of each breeding pair will decrease with increasing human activity as a consequence of population growth; (2) more temporary burrow will be dug and consequently, the distance between burrows will become shorter with increasing human activity; (3) as a consequence of more refuge and reduced inter burrow distance, the flight initiation distance of disturbed populations will become shorter relative to unaffected population; (4) the distance from reproductive burrows to the nearest road will become longer with increasing human activity; and (5) due to the absence of large rocks in the region, marmots impacted by human disturbance will preferentially build reproductive burrows on sites that allow for better surveillance of the area, such as big mounds occurring on the grasslands.