Tiger habitat use dynamics in Bardia-Banke Complex, Nepal using camera trap-based multi-season occupancy framework

Understanding the environmental and anthropogenic correlates of tiger presence in a montane conservation landscape

Understanding the fine-scale movements and habitat use patterns of marine predators is critical for identifying important foraging habitat and guiding effective conservation planning. Here, GPS loggers were used to track chick-rearing Cassin’s auklets (Ptychoramphus aleuticus) at their largest breeding colony, located on Triangle Island, British Columbia, Canada (50°51′35″N; 129°4′34″W). Analyses were conducted at both the individual and population level to assess whether inter-annual variation in habitat use (2014, 2015, and 2017) could be explained by dynamic oceanographic features, such as sea surface temperature (SST) and chlorophyll a concentrations, or by static bathymetric features. At both scales of analyses, the foraging behaviour of Cassin’s auklets was most strongly influenced by SST. At the individual level, birds spent more time foraging in areas with lower SST, relative to other areas visited over the course of a foraging trip. At the population level, the at-sea distribution of Cassin’s auklets varied across years, with birds using areas northwest of colony in 2014 and areas west of the colony in 2015 and 2017. Furthermore, the probability of foraging across the study area was higher in areas with lower SST, suggesting that SST influences the broad-scale foraging distribution of Cassin’s auklets. Identification of the environmental drivers of habitat use across multiple years can be used to help in predicting suitable at-sea habitat across time, leading to more effective conservation management.

Muskrat (Ondatra zibethicus) populations have been declining in North America for decades. The precise cause of these widespread declines has not yet been identified. Over a similar timeframe, wetlands across large regions of North America have been experiencing an invasion of hybrid cattail Typha x glauca. This invasion is associated with many negative consequences for wetlands, including a reduction in biodiversity, open water habitat, and interspersion of water and vegetation. Muskrats are strongly tied to wetlands, especially where there is a high degree of interspersion of water and emergent vegetation. Therefore, a widespread reduction in interspersion caused by T. x glauca invasions may be contributing to widespread muskrat population declines. We sought to better understand the impact of marsh interspersion on fine-scale muskrat habitat use in light of widespread invasions of T. x glauca. We measured intensity of habitat use by muskrats in a large, Typha-dominated marsh in south-central Ontario using camera traps, stratifying camera placement along a gradient of interspersion. We found no correlation between interspersion and intensity of use. The ubiquity of T. x glauca and low overall interspersion at our study site may have prevented a robust test of our hypothesis. Further research is needed to determine precisely how interspersion affects muskrat habitat use at a fine scale, and how potential changes in habitat quality and use may be contributing to widespread muskrat population declines.

The spatial ecology of stalk‐and‐ambush predators like the Eurasian lynx Lynx lynx depends on prey availability and environmental features, yet the relative roles of these factors remain unclear at large spatial scales. In this study, we analysed lynx habitat use across central and southern Finland using snow‐track data from the Wildlife Triangle Scheme (2016–2020) and a joint species distribution modelling framework (HMSC) to assess both environmental drivers and spatial predator–prey associations. The Finnish lynx population offers a unique opportunity to study a contiguous population with stark regional differences in prey availability, enabling inferences about environmental and prey effects on space use. Across the study area, lynx habitat use was primarily associated with structurally complex forests and terrain, as expected for a stalk‑and‑ambush predator. Overall, environmental conditions explained habitat use patterns to a greater degree in the central region than in the south, which we posit is due to differences between the regions in prey species. In the central region, habitat use by lynx and its prey, the mountain hare Lepus timidus , was similar, in contrast to the southern region, where lynx were spatially associated with roe deer Capreolus capreolus and white‐tailed deer Odocoileus virginianus , both of which showed habitat use patterns differing from those of lynx. These results indicate that lynx adjust their space use according to prey availability, while still retaining a core preference for complex habitat, as expected for a stalk‐and‐ambush predator. Our results are a clear demonstration of how the interplay between environmental conditions and community composition of prey shapes a generalist predator's habitat use and how this can contribute to overall resilience at the population level. Our study captures insights into habitat use at the landscape scale across contrasting ecological contexts, with implications for the management and conservation of large carnivores in human‐modified environments.

ABSTRACTSensitivity of bats to land use change depends on their foraging ecology, which varies among species based on ecomorphological traits. Additionally, because prey availability, vegetative clutter, and temperature change throughout the year, some species may display seasonal shifts in their nocturnal habitat use. In the Coastal Plain of South Carolina, USA, the northern long‐eared bat (Myotis septentrionalis), southeastern myotis (Myotis austroriparius), tri‐colored bat (Perimyotis subflavus), and northern yellow bat (Lasiurus intermedius) are species of conservation concern that are threatened by habitat loss. Our objective was to identify characteristics of habitat used by these species during their nightly active period and compare use between summer and winter. We conducted acoustic surveys at 125 sites during May–August and at 121 of the same 125 sites December–March 2018 and 2019 in upland forests, bottomland forests, fields, ponds, and salt marsh and used occupancy models to assess habitat use. The northern long‐eared bat and southeastern myotis (i.e., myotis bats) used sites that were closer to hardwood stands, pine stands, and fresh water year‐round. We did not identify any strong predictors of tri‐colored bat habitat use in summer, but during winter they used bottomland forests, fields, and ponds more than salt marsh and upland forests. During summer and winter, northern yellow bats used sites close to fresh water and salt marsh. Additionally, during summer they used fields, ponds, and salt marsh more than upland and bottomland forests, but in winter they used bottomland forests, fields, and ponds more than upland forest and salt marsh. Our results highlight important land cover types for bats in this area (e.g., bottomland forests, ponds, and salt marsh), and that habitat use changes between seasons. Accounting for and understanding how habitat use changes throughout the year will inform managers about how critical habitat features may vary in their importance to bats throughout the year. © 2021 The Wildlife Society.

Vegetation phenology and productivity drive resource use by wildlife. Vegetation dynamics also reveal patterns of habitat disturbance and recovery. Monitoring these fine‐scale vegetation patterns over large spatiotemporal extents can be difficult, but camera traps (CTs) commonly used to survey wildlife populations also collect data on local habitat conditions. We used CTs (n = 73) from 2016 to 2019 to assess impacts of habitat change in a boreal landscape of northern Canada, where seismic lines for petroleum exploration disturbed wildlife habitat and prompted vegetation restoration efforts. First, we quantified vegetation dynamics from CTs, comparing them to satellite‐based estimates that are typically used to monitor vegetation at broad spatial scales. We then used understory phenology and productivity estimated from CT time‐lapse images to assess vegetation recovery on seismic lines. Finally, we related vegetation dynamics with the habitat use of three wildlife species: sandhill cranes Grus canadensis, woodland caribou Rangifer tarandus, and white‐tailed deer Odocoileus virginianus. CTs provided unique insight into vegetation dynamics that were different from signals measured by satellites, with temporally inconsistent and even some negative correlations between CT and satellite metrics. We found some indication of vegetation recovery on seismic lines that had received restoration treatment, with understory patterns more similar to undisturbed habitat than to seismic lines that did not receive restoration treatment. CTs also provided inferences about wildlife activity related to vegetation resources, which approaches using satellite data failed to detect. Wildlife habitat use tracked vegetation phenology, but did not always increase with vegetation productivity at weekly, 16‐day, or annual intervals. Instead, associations with vegetation productivity depended on species, temporal scale, and productivity metrics. Given the widespread and growing use of CTs to monitor terrestrial wildlife, we recommend their use to simultaneously monitor habitat conditions to better understand the mechanisms that govern wildlife habitat use in changing environments.

Fine-scale habitat use by Daurian hedgehogs in the Gobi-steppe of Mongolia

Analysis of prey remains from beneath feeding perches in Mana Pools National Park in Zimbabwe between 1 March 1987 and 30 April 1988, showed that Nycteris grandis fed mainly on frogs, bats, and arthropods, and occasionally took birds and fish. There was marked seasonal variation in the prey taken, with bats and frogs dominating the biomass at different times. In November 1987, all-night radio-tracking over 15 bat nights revealed significant differences in habitat use between individuals, with one bat foraging along and over the Zambezi River, and another foraging in Acacia albida woodland and over the river. The bats alternated between foraging from continuous flight and making short flights from perches, although foraging over the river usually entailed continuous flight. Significant differences in the use of these foraging strategies between 1987 and an earlier study coincided with differences in November rainfall, and a drastic reduction in the amount of food the bats consumed daily. THE PREY TAKEN BY A PREDATOR may reflect some combination of prey availability and the predator's behavior such as its foraging strategy, pattern of habitat use, and dietary preference. Prevailing local conditions may predude separating these components, but for a variety of reasons, exploring them can be done by the study of some animal-eating bats. First, variation in diet is a recurring pattern among Microchiroptera (e.g., Norberg & Fenton 1988); second, diet may be influenced by the habitat where individuals forage (Herd & Fenton 1983, Swift & Racey 1983); and third, some species use different foraging strategies (e.g., Fenton 1988). There are conflicting opinions about prey specializations shown by insectivorous bats because some have been called specialists on particular groups of prey (e.g., moth strategists -Black 1972), while others are opportunistic in their foraging (Fenton & Morris 1976, Gould 1978, Vaughan 1980, Bell 1980). There is evidence that foraging bats may select only some of the available prey (e.g., Buchler 1976, Brigham 1988), but it may be impossible to distinguish selectivity based on prey taxon from that associated with prey size. For example, Hickey (1988) found that Lasiurus borealis fed almost exclusively on large moths, the only large insects available most of the time. Nycteris grandis is widespread in Africa, with most of its distribution overlapping with areas of rain forest (Smithers 1983). It is large (35 g) and in savannah areas consumes a variety of prey from vertebrates to arthropods (Fenton et a/. 1981) and alternates between two foraging strategies; namely, hunting from continuous flight or from a perch (Fenton et al. 1987). Because flying bats consume energy at about 2 5 times their basal metabolic rates (Thomas 1987), these two foraging strategies should differ dramatically in their costs to the bats. Nycteris grandis use relatively small foraging areas and return to preferred perches to consume captured prey from which they discard some pieces-a set of traits that makes them well suited for studies designed to relate foraging strategy to prey selection, prey availability, and habitat use. The purpose of this study was to examine the prey taken by and foraging behavior of N. grandis in Mana Pools National Park in Zimbabwe (15?44'S, 29021'E). We used data on variation in prey consumed and information about foraging behavior to explore the interactions between prey availability, the bats' foraging strategies, and the prey they took. MATERIALS AND METHODS We documented the prey taken in the 14 month period beginning in March 1987, by collecting prey remains about once a week from under three feeding perches (water tower, house and office-Fig. 1) used by N. grandis. We sorted the remains by order and, where possible, by species. I Received 30 July 1988, revision accepted 12 December 1988. 2 Present address: Department of Biology, University of Calgary, Calgary, Alberta T2N 1N4, Canada. 2 BIOTROPICA 22(1): 2-8 1990 This content downloaded from 157.55.39.243 on Wed, 05 Oct 2016 04:48:02 UTC All use subject to http://about.jstor.org/terms TABLE 1. Monthly changes in the diet of Nycteris grandis between March 1987 and April 1988 as reflected by prey remains collected under the water tower feeding perch. The numbers reflect the prey consumed, while the masses (*) of prey are estimates based on the amounts of culled parts and have averaged bats and birds as 8 g, frogs and fish as 5 g and arthropods as 1 g.

In response to severe vegetation degradation caused by sika deer in Japan, it is important to understand the habitat use trends of the sika deer and sympatric Japanese serows to promote the management and conservation of both species and their habitats. This study used camera traps to examine the trends of habitat use of the two sympatric ungulates in the Kuraiyama Experimental Forest (KEF) at Gifu University. We set camera traps at 20 sites and evaluated the number of individuals photographed for three years. Additionally, we surveyed several environmental factors around the camera trap sites to determine the relationship between species prevalence and habitat features. Both species were photographed at all sites, and some habitat use trends were observed. The deer used the west side of the valley, whereas the serows used the east, with clearer trends further observed in summer. Both ungulates avoided snow cover in winter and used steeper slopes and ridges in several seasons. With the current increase in the deer population, niche overlap between the two species may occur in the common place preferred by both species; therefore, careful monitoring of their relationships and their changes should be continued in the future.

Living on the edge: Opportunities for Amur tiger recovery in China

Assessing the impact of working landscapes on biodiversity and defining locally contextualized management guidelines for productive activities are key for sustainability. Occupancy dynamics provide information about sites in the landscape that are either avoided or preferred by populations through the estimation of extinction and colonization probabilities, respectively. We identified the habitat traits that affected colonization and extinction probabilities of target birds (forest‐dependent, endemic, or conservation concern species) within a Neotropical working landscape by using multi‐season occupancy models to point count data collected through a participatory monitoring approach and considering our imperfect detectability of species in the field. We provided colonization and extinction scenarios according to local land uses (forestry plots, urban‐cropfield areas, and conservation forests) to recommend management activities that could have a positive impact on bird conservation. Shrub cover was key for local colonization of most of our focal species. Increasing values of tree size and tree species richness can enhance microhabitat complexity, which in turn promotes the presence of arboreal birds. Selective forestry management, in which only the largest individuals of a few tree species are extracted, promoted high colonization rates of birds because the structure of the vegetation remains relatively unaffected. In contrast, intensive forestry management plots, in which most trees are removed, resulted detrimental for bird occupancy. Local management guidelines should pay special attention to maintaining shrub cover, tree size, and tree species richness above critical values (>50%, >30 cm, >7 tree species, respectively) to promote habitat use by birds in this type of working landscapes.Abstract in Spanish is available with online material.

Variation in use of edge habitat among populations and species of snakes should reflect underlying causes (e.g., thermal ecology, prey availability) and consequences (e.g., predation on birds' nests) of habitat selection. We compared the habitat use of ratsnakes, Elaphe obsoleta (Say in James, 1823), in Illinois and Ontario and compared habitat use by ratsnakes and racers, Coluber constrictor (L., 1758), in Illinois. Ratsnakes in Illinois used upland forest more and forest edges less than ratsnakes in Ontario. Female ratsnakes in Illinois used edges less than males, regardless of their reproductive status. Relative to ratsnakes, racers preferred forest edges and avoided forest interior. Female racers used edges more than males, especially while gravid. These results, and most of the seasonal patterns in habitat use, were broadly consistent with variation expected from differences in thermoregulatory needs, although other factors potentially influencing habitat use cannot be ruled out. Although it has been proposed that some forest fragmentation is likely to be beneficial for ratsnakes in Canada, such fragmentation may be detrimental to ratsnakes in Illinois but beneficial to racers. Thus, relative to forest-interior species, edge-nesting birds should be more vulnerable to predation by ratsnakes in Ontario, and fragmentation should increase the vulnerability of forest birds to nest predation by racers.

Vegetation characteristics influence fine-scale intensity of habitat use by wild turkey and white-tailed deer in a loblolly pine plantation

Limited information is available on the fine-scale movements and habitat use of juvenile sharks in very shallow (<1 m) nearshore areas and the factors that drive these behaviours. Active acoustic tracking was used to investigate movements and habitat use of juvenile (683 +/- 58 mm total length; mean +/- SD) blacktip reef sharks Carcharhinus melanopterus at Orpheus Island, Australia. Six juveniles were tracked by foot and boat for over 62 h. Juveniles moved in synchrony with tidal cycles, always remaining within very shallow (<1 m) sandy reef flat or reef crest waters during outgoing, low and incoming tides, and using inundated mangrove habitat during higher tides, indicating that tidal fluctuations were a major driver of movement and habitat use. Individuals never left the bay where they were captured or entered deep water beyond the fringing reef, restricting their movements within water <60 cm deep. In general, linearity and rate of movement were significantly higher during incoming or outgoing tides, whereas these measures were significantly lower during higher tide heights when juveniles were occupying mangrove habitats. The observed behaviour was most likely a predator-avoidance strategy, highlighting the importance of mangrove root habitat use by juvenile blacktip reef sharks in coastal nursery areas and indicating that this may be an essential habitat for the young of this species.

Habitat use of juvenile southern flounder Paralichthys lethostigma was examined within a shallow estuarine seascape during June and July 2011 using acoustic telemetry. Fine-scale movement and habitat use of P. lethostigma was investigated with an acoustic positioning system placed in a seascape that varied in habitat type, physicochemical conditions and bathymetry. The use of different habitat types was examined with Euclidean distance-based analyses, and generalized additive models were used to determine the relative importance of habitat type relative to physicochemical conditions and bathymetry. Tracks of P. lethostigma ranged in distance between 1477 and 8582 m and speed was 4·2 ± 1·1 m min⁻¹ (mean ± s.e.) for all P. lethostigma combined. Depth, slope and habitat type had the most influence on P. lethostigma occurrence and deep sandy areas with shallow slopes were used most frequently. In addition, depth use by P. lethostigma was influenced by tidal cycles, indicating habitat use varies temporally and is dynamic. Finally, temperatures <30·5° C were used more than warmer waters within the study area. The results successfully identify movements by juvenile P. lethostigma, and indicate that definitions of essential habitats need to account for dynamics in habitat use.