A cautionary tale comparing spatial count and partial identity models for estimating densities of threatened and unmarked populations

Global Ecology and Conservation, Journal Year: 2022, Volume and Issue: 38, P. e02268 - e02268

Published: Aug. 18, 2022

Population monitoring is critical to wildlife conservation, but density estimation difficult for wide-ranging, unmarked species inhabiting remote habitats. Furthermore, recent investigations into with camera trap data has revealed models be potentially unreliable, prompting cautious application and continued model development. Two related approaches increasing appeal include spatial count (SC), which infer latent identities from the pattern of detections, partial identity (SPIM), additionally leverage covariates (e.g., sex, antler point count, presence GPS/radio collar). To assess performance models, we applied SC SPIM threatened boreal caribou in Canada, are declining have few rigorous estimates across their broad distribution inform conservation efforts. In particular, focused on two spatially proximate ranges northern Alberta, Canada that differ estimated demographic trends, disturbance histories, abundances predators apparent competitors. Estimates varied over a 4 year period (2016 – 2019), were higher region more stable reported growth rates less anthropogenic (mode estimates: 155 225/1000 km2 vs. 19 96/1000 km2). However, differed by modeling approach had low variable precision, hindering inferences about population status trajectories. Simulations suggest may been biased precise. likely underestimated mistaking detections neighboring individuals as recaptures single individual, although also overestimated inflating assignment probabilities non-existent individuals. Findings highlight need explore how grouping dynamics non-independent movement violate assumptions reduce ability distinguish We advocate investigation accuracy approaches, ecological sampling conditions appropriate different coordination efforts analyses improve inferences.

Language: Английский

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Will this umbrella leak? A caribou umbrella index for boreal landbird conservation

Conservation Science and Practice, Journal Year: 2023, Volume and Issue: 5(4)

Published: March 10, 2023

Abstract Conservation approaches that efficiently protect multiple values, such as the umbrella species concept, have been widely promoted with expected dramatic ecosystem changes. Due to its social and cultural importance, recent declining trends, boreal populations of woodland caribou suggested potential for other taxa, landbirds. We propose a generic pixel‐based index focuses on fine‐grained habitat overlaps. In light ongoing conservation efforts worldwide implementing area‐based targets (e.g., 30% by 2030), we used random neutral model baseline, opposed no‐conservation scenario, which has elsewhere. found efficiency an 71 co‐occurring landbirds—three are priority species—in Northwest Territories, Canada, is generally lower than our model, 53% presented negative medians interquartile range not overlapping zero. conclude in cases where drive decision‐making issue at stake involves identifying areas conserve—not whether conserve—woodland may be leaky most landbird these might need complementary actions brought from rain.

Language: Английский

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Multispecies modelling reveals potential for habitat restoration to re‐establish boreal vertebrate community dynamics

Journal of Applied Ecology, Journal Year: 2021, Volume and Issue: 58(12), P. 2821 - 2832

Published: Sept. 7, 2021

Abstract The restoration of habitats degraded by industrial disturbance is essential for achieving conservation objectives in disturbed landscapes. In boreal ecosystems, disturbances from seismic exploration lines and other linear features have adversely affected biodiversity, most notably leading to declines threatened woodland caribou. Large‐scale needed, yet empirical assessments effectiveness on wildlife communities remain rare. We used 73 camera trap deployments 2015 2019 joint species distribution models investigate how habitat use the larger vertebrate community (>0.2 kg) responded variation key line characteristics (line‐of‐sight, width, density mounding) following treatments a landscape oil gas development northeastern Alberta. proportion explained was low comparison type season, suggesting short‐term responses were relatively weak. However, we found that with consistent restored conditions predicted support an altered composition, reduced wolf coyote, thereby indicating will result contact rates between caribou these predators. Synthesis applications . Our analysis provides framework assess predict emerging efforts. With growing importance species, recommend longer‐term monitoring combined landscape‐scale comparisons different approaches more fully understand direct critical investments. Only combining rigorous multispecies large‐scale restoration, effectively conserve biodiversity within rapidly changing environments.

Language: Английский

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Evaluating and integrating spatial capture–recapture models with data of variable individual identifiability

Ecological Applications, Journal Year: 2021, Volume and Issue: 31(7)

Published: July 10, 2021

Abstract Spatial capture–recapture (SCR) models have become the preferred tool for estimating densities of carnivores. Within this family are variants requiring identification all individuals in each encounter (SCR), a subset only (generalized spatial mark–resight, gSMR), or no individual (spatial count presence–absence). Although technique has been shown through simulation to yield unbiased results, consistency and relative precision estimates across methods real‐world settings seldom considered. We tested suite ranging from those detections unmarked others that integrate remote camera, physical capture, genetic, global positioning system (GPS) data into hybrid model, estimate population black bears, bobcats, cougars, coyotes. For species, we genotyped fecal DNA collected with detection dogs during 20‐d period. A species was affixed GPS collars bearing unique markings resighted by cameras over 140 d contemporaneous scat collection. Camera‐based gSMR produced density differed <10% genetic SCR coyotes once important sources variation (sex behavioral status) were controlled for. 33% higher than gSMR. The cause discrepancies likely attributable challenges designing study compatible disparate home range sizes difficulty collecting sufficient timeframe which demographic closure could be assumed. Unmarked estimated varied greatly SCR, but became more consistent wherein identifiable. Hybrid containing exhibited most precise species. studies sparse can obtained strictest model assumptions unlikely met, suggest researchers use caution making inference lacking identity. best further recommend at least is marked multiple sets incorporated when possible.

Language: Английский

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Human disturbance and shifts in vertebrate community composition in a biodiversity hotspot

Conservation Biology, Journal Year: 2021, Volume and Issue: 36(2)

Published: Aug. 3, 2021

Abstract Understanding how human modification of the landscape shapes vertebrate community composition is vital to understanding current status and future trajectory wildlife. Using a participatory approach, we deployed largest camera‐trap network in Mesoamerica date investigate anthropogenic disturbance occupancy co‐occurrence terrestrial species tropical biodiversity hotspot: Osa Peninsula, Costa Rica. We estimated richness different categories land protection with rarefaction analysis expected joint distribution model that included covariates for disturbance, protection, habitat quality, availability. Areas most stringent land‐use protections (e.g., Corcovado National Park, 24 [95% CI 23–25]) harbored significantly more than unprotected areas (20 [19.7–20.3]), mainly due reduced presence large‐bodied conservation concern jaguar Panthera onca white‐lipped peccary Tayassu pecari ). Small‐bodied generalist species, such as opossums (Didelphidae) armadillos ( Dasypus novemcinctus ), contrast, were common at disturbed sites, resulting significant difference between sites low high disturbance. Co‐occurrence was also associated response Similar responses create two groups those whose site‐level usually increased decreased. The absence entails an important loss ecological function can hinder forest development maintenance. Efforts protect restore forested landscapes are likely having positive effect on abundance some threatened species. These efforts, however, must be sustained expanded increase connectivity ensure long‐term viability wildlife community.

Language: Английский

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Slowing down wolves to protect boreal caribou populations: a spatial simulation model of linear feature restoration

Ecosphere, Journal Year: 2019, Volume and Issue: 10(10)

Published: Oct. 1, 2019

Abstract In Canada, boreal caribou ( Rangifer tarandus ) are declining in numbers, part due to increased predation by wolves Canis lupus ). One management option reduce wolf–caribou interactions and thus protect is remove man‐made linear features LF s), structures such as roads, trails, cut lines, which used traveling paths. Linear increase wolf speed could additionally facilitate entry into habitat. Our goal was quantify the expected effect of removal on mortality investigate whether this restoration be a sufficient measure stop declines. We simulated effects adult calf survival spatially explicit encounter models. The models were parameterized using Global Positioning System GPS data, hidden Markov HMM information from published literature. Complete decreased reduced mortality. proportional reduction ranged 10 25% its original value, 8 23%, depending density, number packs, kill probability given an encounter, detection distance for caribou. Building model output, we empirical data calculate mortalities finite rate annual population change, . Assuming that or less wolf‐related, stayed below one, is, populations kept declining, even with complete restoration. With 50% wolves, stopped () if at least 19 24%. However, these values not achieved majority parameter combinations our study, Given single unlikely case example illustrate how make small contribution portfolio short‐term long‐term options

Language: Английский

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Community-level modelling of boreal forest mammal distribution in an oil sands landscape

The Science of The Total Environment, Journal Year: 2020, Volume and Issue: 755, P. 142500 - 142500

Published: Sept. 26, 2020

Language: Английский

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Behavioral “bycatch” from camera trap surveys yields insights on prey responses to human‐mediated predation risk

Ecology and Evolution, Journal Year: 2022, Volume and Issue: 12(7)

Published: July 1, 2022

Human disturbance directly affects animal populations and communities, but indirect effects of on species behaviors are less well understood. For instance, may alter predator activity cause knock-on to predator-sensitive foraging in prey. Camera traps provide an emerging opportunity investigate such disturbance-mediated impacts across multiple scales. We used camera trap data test predictions about behavior three ungulate (caribou

Language: Английский

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An interspecific foraging association with polar bears increases foraging opportunities for avian predators in a declining Arctic seabird colony

Ecology and Evolution, Journal Year: 2024, Volume and Issue: 14(3)

Published: March 1, 2024

Abstract Interspecific foraging associations (IFAs) are biological interactions where two or more species forage in association with each other. Climate‐induced reductions Arctic sea ice have increased polar bear ( Ursus maritimus ) seabird colonies, which creates opportunities for avian predators. We used drone video of bears within a common eider Somateria mollissima colony on East Bay Island (Nunavut, Canada) 2017 to investigate herring gull Larus argentatus bears. recorded nest visitation by gulls following n = 193 flushing events from nests during incubation. The probability visiting higher number present (β 0.14 ± 0.03 [SE], p < .001) and previously visited 1.14 0.49 .02). In our model examining the consuming eggs nests, we failed detect statistically significant effects 0.09 0.05 .07) −0.92 0.71 .19). Gulls preferred visit behind (χ 2 18, df 1, .0001), indicating risk averse presence Our study provides novel insights an IFA, evidence that capitalize made available due disturbance associated bears, as eiders disturbed off their allow easier access eggs. suggest IFA between is parasitic, terrestrial resources would eventually been consumed This finding has implications estimating energetic contribution bird summer diets total clutches consume may be reduced

Language: Английский

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Native prey, not landscape change or novel prey, drive cougar (Puma concolor) distribution at a boreal forest range edge

Ecology and Evolution, Journal Year: 2024, Volume and Issue: 14(4)

Published: April 1, 2024

Abstract Many large carnivores, despite widespread habitat alteration, are rebounding in parts of their former ranges after decades persecution and exploitation. Cougars ( Puma concolor ) apex predator with remaining northern core range constricted to mountain landscapes areas western North America; however, cougar populations have recently started several locations across America, including northward boreal forest landscapes. A camera‐trap survey multiple Alberta, Canada, delineated a edge; within this region, we deployed an array 47 camera traps random stratified design landscape spanning gradient anthropogenic development relative the predicted expansion front. We completed hypotheses information‐theoretic framework determine if occurrence is best explained by natural land cover features, or competitor prey activity. that features from resource extraction invading white‐tailed deer Odocoileus virgianius explain distribution at edge. Counter our predictions, activity native prey, predominantly snowshoe hare Lepus americanus ), was predictor Small‐bodied items particularly important for female sub‐adult cougars may support breeding individuals northeast forest. Also, counter there not strong relationship detected between gray wolf Canis lupus However, further investigation recommended as possibility into multi‐prey system, where wolves been controlled, could negative consequences conservation goals region (e.g. recovery woodland caribou [ Rangifer tarandus ]). Our study highlights need monitor contemporary distributions inform management objectives carnivores recover America.

Language: Английский

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