Introduction :
Large mammals around the world face serious threats and experience
massive decline in their populations and geographic ranges (Ceballos et
al. 2015, 2017; Ripple et al. 2014; Karanth, 2009; Ceballos & Ehrlich
2002). Protected areas (PAs) have become the last refuge of many
threatened mammals and have contributed to conservation of some flagship
species yet their effectiveness to halt decline of other sympatric
species remains questioned (UNEP-WCMC & IUCN, 2021; CBD, 2020; Li et
al.2020; Geldmann et al. 2019; Schulze et al. 2018; Barnes et al. 2016;
Ceballos et al. 2015; Geldmann et al. 2013; Hoffmann et al. 2010).
Increasing pressure on the environment has compromised the intactness of
natural habitat and species ability to procreate and persist in a
healthy population (Crooks et al. 2017; Wilson et al. 2016). Extinction
risk of mammals in small, degraded, and isolated habitats increase in
long run through population decline and loss of genetic diversity
(Frankham et al. 2002, 2010).
The sloth bear Melursus ursinus is an endemic mammal of the
Indian sub-continent occurring in a wide range of habitats including dry
or moist forest, savannah, scrublands and grasslands (Dhariya et al.
2020; Garshelis et al.1998). However, their populations have declined by
almost 50 % over the last three decades and are categorized as
“vulnerable” in IUCN Red List (Dhariya et al. 2020). They have become
extinct from entire country in Bangladesh (Islam et al.2013) and
possibly from Bhutan and locally from different habitat patches of India
and Nepal (Dhariya et al. 2020; Garshelis et al 1998). They were once
present along continuous strip of forest and grasslands in the southern
Nepal until 1950s when expansion of human settlement and agriculture
confined them primarily in few protected areas (Amin et al. 2018;
Jnawali et al. 2011). While distribution, habitat use, population and
conservation ecology of sympatric co-predators’ tiger and leopard is
well explored (Subedi et al. 2021; Thapa et al 2021; Lamichhane et al.
2019; 2017; Dhungana et al. 2019, 2018; Kafley et al. 2019; Pokheral et
al. 2019; Karki et al. 2015; Barber-Meyer et al. 2013; Bhattarai et al.
2012; Carter et al.2012; Smith 1984), similar studies for sloth bears
are limited (Lamichhane et al. 2016; Laurie & Seidensticker, 1977;
Garshelis et al. 1999; Joshi et al. 1995,1997,1999) to from a conclusive
view on its current conservation status.
Information on the species spatial distribution pattern in the wild and
factors that influence this pattern are critical for setting
conservation priorities and site-specific management actions for
securing these population over time. Primarily, species distribution and
habitat use are determined by the availability and spatial variation of
food resources and the extent of natural and anthropogenic threats
(Ceballos & Ehrlich, 2002; Schipper et al. 2008). Unlike other
carnivores, bears exhibit a different set of morphological
specializations for diet (Sacco et al. 2004). Sloth bears are specially
adapted for myrmecophagy with the composition of diet varying with
temporal and spatial availability of the food resources particularly
termites and fruits (Philip et al.2021; Palei et.al. 2014, 2020; Rather
et.al. 2020; Mewada et al. 2019,2015; Baskaran et al.2015; Khanal &
Thapa, 2014; Sukhadiya et al. 2013; Baskaran & Desai.2010; Bargali
et.al. 2004; Joshi et.al,1997; Laurie & Seidensticker,1977). In fruit
rich areas, sloth bears play important role in the dispersal of seed and
regeneration of fruit plants (Sreekumar & Balakrishnan, 2002) thus
playing important role in maintenance of forest structure and
composition. They largely prefer habitats away from human disturbance
(Joshi et al. 1999; Babu et.al 2015, Ghimire & Thapa,2014; Ratnayeke
et.al.2007) but they have also been reported to tolerate some degree of
disturbance in human-dominated landscapes (Puri et.al 2015, Bargali et
al. 2012; Akhtar et al.2004, 2007). Prevalence of human-sloth bear
conflict in India (Rajpurohit & Kruasman, 2000; Debata et al.
2012,2017; Garcia et al. 2016; Dhamorikar et al. 2017; Bargali et al.
2005; Ratnayeke et al 2014; Ahmed et al.2012; Sharp et al.2020; Ketting
et al.2020) and Nepal (Pokharel et al. 2020; Ruda et al. 2020; Silwal et
al. 2019; Lamichhane et al. 2018; Acharya et al.2016) is one of the
threats to its survival. Additionally, removal of the individuals
through poaching or live capture for use as ‘dancing bears’ is not
common but can be detrimental enough for a population that is already
small, isolated and threatened.
Direct observation of sloth bears is difficult because of their rare,
elusive, and aggressive nature. We use occupancy analysis which is
widely used in recent years and have evolved as a strong, flexible, and
viable method for estimating species distribution and occupancy dynamics
while accounting for possible non-detection as well as incorporating
predictor variables measured remotely or during the observation process
in field (MacKenzie et al.2002,2003, 2004, 2017; Bailey et al. 2014;
MacKenzie & Nichols 2004; MacKenzie & Royle, 2005). We employed
single-season occupancy model for understanding the distribution and
occupancy dynamics of the sloth bears and its ecological, environmental,
and anthropogenic determinants.