Prioritizing Tiger Conservation through Landscape Genetics and Habitat Linkages

PLoS ONE, Journal Year: 2014, Volume and Issue: 9(11), P. e111207 - e111207

Published: Nov. 13, 2014

Even with global support for tiger (Panthera tigris) conservation their survival is threatened by poaching, habitat loss and isolation. Currently about 3,000 wild tigers persist in small fragmented populations within seven percent of historic range. Identifying securing linkages that connect source maintaining landscape-level gene flow an important long-term strategy endangered carnivores. However, corridors link regional are often lost to development projects due lack objective evidence on importance. Here, we use individual based genetic analysis combination landscape permeability models identify prioritize movement across the Central Indian Landscape. By using a panel 11 microsatellites identified 169 from 587 scat 17 tissue samples. We detected four clusters India limited among three them. Bayesian likelihood analyses as having recent immigrant ancestry. Spatially explicit occupancy obtained extensive landscape-scale surveys 76,913 km(2) forest was found be only 21,290 km(2). After accounting detection bias, covariates best explained were large, remote, dense patches; large ungulate abundance, low human footprint. used probability parameterize modeling least-cost circuit theory pathway analyses. Pairwise differences (FST) between better modeled linkage costs (r>0.5, p<0.05) compared Euclidean distances, which consonance observed fragmentation. The results our study highlight many may still functional there contemporary migration. Conservation efforts should provide legal status corridors, smart green infrastructure mitigate impacts, restore habitats where connectivity has been lost.

Language: Английский

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Sampling scales define occupancy and underlying occupancy–abundance relationships in animals

Ecology, Journal Year: 2017, Volume and Issue: 99(1), P. 172 - 183

Published: Oct. 24, 2017

Occupancy-abundance (OA) relationships are a foundational ecological phenomenon and field of study, occupancy models increasingly used to track population trends understand interactions. However, these two fields inquiry remain largely isolated, despite growing appreciation the importance integration. For example, using infer in abundance is predicated on positive OA relationships. Many studies collect data that violate geographical closure assumptions due choice sampling scales application mobile organisms, which may change how related. Little research, however, has explored different designs affect We develop conceptual framework for understanding definition drives explore spatial temporal scales, unit (areal vs. point sampling), predictions simulations, test them empirical from remote cameras 11 medium-large mammals. Surprisingly, our simulations demonstrate when sampling, unaffected by grain (i.e., cell size). In contrast, areal (e.g., species atlas data), affected grain. Furthermore, also where curvature relationship increases with duration. Our results support predictions, showing at any given abundance, does not estimates, but longer surveys do increase estimates. rare (low occupancy), estimates will quickly surveys, even while remains constant. clearly without true occupancy. The independence depends unit. Point-sampling can, provide unbiased multiple simultaneously, irrespective home-range size. use trend monitoring needs explicitly articulate chosen define occupancy-abundance relationship.

Language: Английский

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Framing pictures: A conceptual framework to identify and correct for biases in detection probability of camera traps enabling multi‐species comparison

Ecology and Evolution, Journal Year: 2019, Volume and Issue: 9(4), P. 2320 - 2336

Published: Jan. 23, 2019

Obtaining reliable species observations is of great importance in animal ecology and wildlife conservation. An increasing number studies use camera traps (CTs) to study communities, an effort made make better reuse the large amounts data that are produced. It these circumstances it becomes paramount correct for species- study-specific variation imperfect detection within CTs. We reviewed literature used our own experience compile a list factors affect CT animals. did this conceptual framework six distinct scales separating out influences (a) characteristics, (b) specifications, (c) set-up protocols, (d) environmental variables. identified 40 can potentially influence animals by CTs at scales. Many were related only few overarching parameters. Most characteristics scale with body mass diet type, most differ season or latitude such remote sensing products like NDVI could be as proxy index capture variation. Factors microsite probably important determining The type specific research question will determine which should corrected. Corrections done directly adjusting metric interest using covariates statistical framework. Our design help when analyzing data. Furthermore, provides overview reported them repeatable, comparable, their reusable. This greatly improve possibilities global analyses (reused)

Language: Английский

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Wildlife winners and losers in an oil sands landscape

Frontiers in Ecology and the Environment, Journal Year: 2018, Volume and Issue: 16(6), P. 323 - 328

Published: May 7, 2018

Energy development and consumption drive changes in global climate, landscapes, biodiversity. The oil sands of western Canada are an epicenter production, creating landscapes without current or historical analogs. Science policy often focus on pipelines species‐at‐risk declines, but we hypothesized that differential responses to anthropogenic disturbances shift the entire mammal community. Analysis data collected from 3 years camera trapping species distribution models indicated features best explained distributions ten included study. Relative abundances some mammals were positively correlated with feature density, others negatively correlated. Effect sizes larger than for natural features. Increasing spatial complexity, access multiple habitats, new forage sources favor generalist predators browsers, detriment specialists, likely altering ecological processes. This issue has far‐reaching implications: as landscape so too does its community, serving a bellwether future change energy worldwide.

Language: Английский

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Animal movement affects interpretation of occupancy models from camera‐trap surveys of unmarked animals

Ecosphere, Journal Year: 2018, Volume and Issue: 9(1)

Published: Jan. 1, 2018

Abstract Occupancy models are increasingly applied to data from wildlife camera‐trap ( CT ) surveys estimate distribution, habitat use, or relative abundance of unmarked animals. Fundamental the occupancy modeling framework is temporal pattern detections at camera stations, which influenced by animal population density and speed scale movement. How these factors interact with sampling designs affect interpretation parameter estimates unclear. We developed a simple yet ecologically relevant movement simulation create for populations varying in rate, home range area, density. also varied design duration s our simulated domain. A single‐species model was fitted detection histories, model‐estimated probabilities were compared asymptotic proportion area occupied PAO ), calculated as union all ranges. sensitive scenarios. overestimated when low animals moved quickly over large ranges this positive bias insensitive duration. Conversely, underestimated slowly large‐ intermediately sized This negative decreased increasing lower s. Our results emphasize that depends on underlying processes driving detections, specifically density, may not reliably reflect variation processes. recommend carefully defining if it order better match analytical frameworks ecology sampled species.

Language: Английский

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Occupancy models for citizen‐science data

Methods in Ecology and Evolution, Journal Year: 2019, Volume and Issue: 10(1), P. 8 - 21

Published: Jan. 1, 2019

Abstract Large‐scale citizen‐science projects, such as atlases of species distribution, are an important source data for macroecological research, understanding the effects climate change and other drivers on biodiversity, more applied conservation tasks, early‐warning systems biodiversity loss. However, challenging to analyse because observation process has be taken into account. Typically, leads heterogeneous non‐random sampling, false absences, detections, spatial correlations in data. Increasingly, occupancy models being used atlas We advocate a dual approach strengthen inference from citizen science questions programme is intended address: (a) survey design should chosen with particular set associated analysis strategy mind (b) statistical methods tailored not only those but also specific characteristics review consequences choices that typically need made atlas‐style projects. These include resolution sampling units, allocation effort space, collection information about process. On side, we extensions basic frequently necessary data, including dealing heterogeneity, non‐independent violation closure assumption. New technologies, cell‐phone apps fixed remote detection devices, revolutionizing There opportunity maximize usefulness resulting datasets if protocols rooted robust designs issues considered. Our provides guidelines designing new projects overview current can

Language: Английский

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Examining the occupancy–density relationship for a low‐density carnivore

Journal of Applied Ecology, Journal Year: 2017, Volume and Issue: 54(6), P. 2043 - 2052

Published: Feb. 8, 2017

Summary The challenges associated with monitoring low‐density carnivores across large landscapes have limited the ability to implement and evaluate conservation management strategies for such species. Non‐invasive sampling techniques advanced statistical approaches alleviated some of these can even allow spatially explicit estimates density, one most valuable wildlife tools. For species, individual identification comes at no cost when unique attributes (e.g. pelage patterns) be discerned remote cameras, while other species require viable genetic material expensive laboratory processing assignment. Prohibitive costs may still force efforts use distribution or occupancy as a surrogate which not appropriate under many conditions. Here, we used large‐scale study fisher Pekania pennanti effectiveness an approximation particularly informing harvest decisions. We combined cameras baited hair snares during 2013–2015 sample 70 096‐km 2 region western New York, USA . fit Royle–Nichols models detection–non‐detection data collected by spatial capture–recapture (SCR) encounter obtained genotyped samples. Variation in state variables within 15‐km grid cells was modelled function landscape known influence distribution. found close relationship between cell from using those SCR model, likely due informative covariates extent resolution that worked well movement ecology Fisher density were both positively proportion coniferous‐mixed forest negatively road density. As result, recommendations similar models, though relative variation dampened data. Synthesis applications Our work provides empirical evidence make inferences regarding focal population more encounters selected grain approximates is marginally smaller than home range size. When alone chosen cost‐effective variable monitoring, simulation sensitivity analyses should understand how will affected aspects design ecology.

Language: Английский

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Estimating mammalian species richness and occupancy in tropical forest canopies with arboreal camera traps

Remote Sensing in Ecology and Conservation, Journal Year: 2016, Volume and Issue: 3(3), P. 146 - 157

Published: Nov. 29, 2016

Abstract Large and medium‐bodied rainforest canopy mammals are typically surveyed using line transects, but these labour intensive usually ignore nocturnal species. Camera traps have become the preferred tool for assessing terrestrial mammal communities, rarely been used arboreal Here, we compare efficiency of camera trapping with transects inventorying medium large‐sized mammals, assess viability in trees to model habitat occupancy. We installed 42 traps, spaced 2 km apart, Maijuna‐Kichwa Regional Conservation Area, Peru walked 2014 diurnal on 22 trails at same site. compared each method species accumulation curves. applied a multi‐species occupancy model, while examining effect height detection probabilities, including distance from village river as covariates examine variability In 3147 days, 18 were detected by cameras, 11 recorded transects. Ten both methods. Diurnal more quickly less effort than site, although some easily during Habitat was positively correlated two species, negatively one. Detection probabilities increased modestly height. Practical limitations include requirement specialized climbing techniques, well potential false triggers, requiring extended processing time. Arboreal is an efficient viable option studying their distribution relative environmental or anthropogenic variables when abundance density estimates not required.

Language: Английский

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Density‐dependent home‐range size revealed by spatially explicit capture–recapture

Ecography, Journal Year: 2015, Volume and Issue: 39(7), P. 676 - 688

Published: July 16, 2015

The size of animal home ranges often varies inversely with population density among populations a species. This fact has implications for monitoring using spatially explicit capture–recapture (SECR) models, in which both the scale home‐range movements σ and D usually appear as parameters, may vary populations. It will be appropriate to model structural relationship between population‐specific values these rather than assume independence. We suggest re‐parameterizing SECR k p = √ , where relates degree overlap subscript distinguishes observe that is nearly constant spanning range densities. justifies fitting separate are replaced by single parameter density‐dependent derived parameter. Continuous spatial variation also modelled, scaled non‐Euclidean distance detectors locations animals. illustrate methods data from automatic photography tigers Panthera tigris across India, populations, mist‐netting ovenbirds Seiurus aurocapilla Maryland, USA, within over time, live‐trapping brushtail possums Trichosurus vulpecula New Zealand, modelling one population. Possible applications limitations discussed. A constant, while varies, provides parsimonious null SECR. concise summary empirical useful comparative studies. expect deviations this model, particularly dependence on covariates, biologically interesting.

Language: Английский

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Effects of human impacts on habitat use, activity patterns and ecological relationships among medium and small felids of the Atlantic Forest

PLoS ONE, Journal Year: 2018, Volume and Issue: 13(8), P. e0200806 - e0200806

Published: Aug. 1, 2018

Competition theory and niche suggest that two morphologically similar species may coexist by reducing the overlap of at least one dimension their ecological niche. The medium small Neotropical felids are an interesting group carnivore for studying intraguild competition. Due to differences in size it is expected larger ocelot exert strong interference competition on smaller (southern tiger cat, margay jaguarundi); which, turn, exploitative among themselves. Moreover, landscape changes due human activities alter these interspecific interactions. We studied habitat use spatial temporal relations Atlantic Forest felids, a with different levels anthropogenic impact. estimated detection probability, occupancy probability cats whether parameters affected environmental variables or ocelot. daily activity patterns between pairs four response also potential have occurred relation ocelot's probability. small- medium-size was negatively associated intensity humans. Co-occurrence models indicated southern decreased This effect higher as disturbance increased. cat became more nocturnal sites access, suggesting they be temporally avoiding encounters humans dogs. Conservation depends not only establishment implementations protected areas but management human's land uses.

Language: Английский

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