Motion‐sensitive cameras track population abundance changes in a boreal mammal community in southwestern Yukon, Canada

Journal of Wildlife Management, Год журнала: 2024, Номер 88(4)

Опубликована: Фев. 23, 2024

Abstract Motion‐sensitive cameras are commonly used to monitor wildlife occupancy rates; however, few studies have assessed whether data from correlated with density estimates obtained more traditional labor‐intensive methods such as those based on capture‐mark‐recapture. We a boreal forest community test camera were densities estimated independent monitoring methods. placed 72 covert in the around Lhù'ààn Mân' (Kluane Lake), Yukon, Canada, for 7 years and tracked changes population by hit rates. independently of snowshoe hares ( Lepus americanus ) red squirrels Tamiasciurus hudsonicus using capture‐mark‐recapture via live trapping, Canada lynx Lynx canadensis ), coyotes Canis latrans moose Alces snow track transects. Density conventional aerial surveys also periodically available moose. Except squirrels, rates highly methods, including across large range corresponding cyclic dynamics several species. Accordingly, we infer that motion‐sensitive could supplement or replace key species food webs. Using change has advantages; they require less effort field, non‐invasive compared live‐trapping, include multiple at same time, rely weather than either Tracking vast is becoming increasingly necessary because climate landscape our validate use provide useful quantitative method state‐of‐the‐environment reporting.

Язык: Английский

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Habitat alteration or climate: What drives the densities of an invading ungulate?

Global Change Biology, Год журнала: 2024, Номер 30(4)

Опубликована: Апрель 1, 2024

Abstract Anthropogenic habitat alteration and climate change are two well‐known contributors to biodiversity loss through changes species distribution abundance; yet, disentangling the effects of these factors is often hindered by their inherent confound across both space time. We leveraged a contrast in associated with jurisdictional boundary between Canadian provinces evaluate relative spatial variation on white‐tailed deer ( Odocoileus virginianus ) densities. White‐tailed an invading ungulate much North America, whose expansion into Canada's boreal forest implicated decline caribou Rangifer tarandus ), listed as Threatened Canada. estimated densities using 300 remote cameras 12 replicated 50 km 2 landscapes over 5 years. were significantly lower areas where winter severity was higher. For example, predicted declined from 1.83 0.35 deer/km when increased lowest value median value. There tendency for increase increasing alteration; however, magnitude this effect approximately half that climate. Our findings suggest primary driver populations; understanding mechanisms underpinning relationship requires further study over‐winter survival fecundity. Long‐term monitoring at invasion front needed drivers abundance time, particularly given unpredictability prevalence extreme weather events.

Язык: Английский

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Using camera traps and N‐mixture models to estimate population abundance: Model selection really matters

Methods in Ecology and Evolution, Год журнала: 2024, Номер 15(5), С. 900 - 915

Опубликована: Апрель 11, 2024

Abstract Estimating the abundance or density of wildlife populations is a critical part species conservation and management, but estimates can vary greatly in precision accuracy according to sampling statistical methods, ecological variation, sample size. We used images moose ( Alces americanus ) from camera traps parameterize N‐mixture models tested effect conditions, spatial scale measurement, criteria define independent detections on population abundance. compared model those generated empirically with aerial survey data, standard method for many ungulate. explored sensitivity choice based common criterion parsimony. The two most parsimonious (i.e. AIC c were considerably biased, producing implausibly large imprecise Most other produced that ecologically realistic relatively accurate. by was not overly sensitive formulation models, at which conditions measured, detection extension Our results suggested parsimony poor measure predictive model. recommend using suite generate predictions instead single top‐ranked Collecting processing data less expensive took time, provided broader set insights into behaviour co‐occurrence competitors predators.

Язык: Английский

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Ungulate occurrence in forest harvest blocks is influenced by forage availability, surrounding habitat and silviculture practices

Ecological Solutions and Evidence, Год журнала: 2023, Номер 4(2)

Опубликована: Апрель 1, 2023

Abstract Forest harvesting causes habitat loss and alteration can change predator–prey dynamics. In Canada, forest has shifted the distribution abundance of ungulates (deer, elk moose) that prefer early seral forest, resulting in unsustainable caribou predation by shared predators (bears, cougars wolves). Long‐term solutions for recovery require management to reduce ungulate prey species within ranges. Silviculture practices applied after directly affect amount forage available harvested areas, therefore influence distribution, but few studies have completed detailed assessments on how specific treatments site preparation, planting stand tending use harvest blocks. We used camera traps, silviculture data, GIS‐derived disturbance vegetation data collected at field sites investigate occurrence blocks west‐central Alberta, Canada. compared seasonal investigated site‐specific characteristics, surrounding density, fine‐scale influenced Deer, moose was higher summer winter. Elk, white‐tailed deer with greater availability species. Moose a lower road density area, further from seismic lines proportion area. younger Mule densities lodgepole pine, mule also had been tended. Our study provides information response methods linking wildlife forestry practices, providing practical scientific inform sustainable forestry. Translating this research into landscape decisions could benefit boreal biodiversity, including threatened like caribou, culturally economically important deer, moose.

Язык: Английский

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One size does not fit all: A novel approach for determining the Realised Viewshed Size for remote camera traps

Methods in Ecology and Evolution, Год журнала: 2025, Номер unknown

Опубликована: Фев. 27, 2025

Abstract Camera traps (CTs) have become cemented as an important tool of wildlife research, yet their utility is now extending beyond academics, CTs can contribute to inclusive place‐based management. From advances in analytics and technology, CT‐based density estimates are emerging field research. Most methods require estimate the size viewshed monitored by each CT, a parameter that may be highly variable difficult quantify. We developed tested standardized analytical method allowing us predict probability photographic capture it varies within CT viewshed. investigated how changes due environmental influences (vegetation structure, ambient temperature, speed subject time day), addition internal factors from themselves (sensitivity settings, number photographs taken brand). then summarize these spatial kernels into Realised Viewshed Size (RVS)—the corrected for use denominator photograph‐based Random Encounter Staying Time (REST) or Front (TIFC) estimators. found RVS values heavily influenced location‐specific structure), technological delays associated with themselves, (refractory period) settings. computed using our methodology substantially smaller than sizes reported literature. Imprecision surrounding areas propagate bias when implementing Our change practitioners consider estimators thus increasing reliability estimation, contributing more accessible management practices.

Язык: Английский

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The spatial dynamics of red deer (Cervus elaphus) in fenced Mediterranean landscapes during periods of limited resources

European Journal of Wildlife Research, Год журнала: 2025, Номер 71(3)

Опубликована: Май 29, 2025

Язык: Английский

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Reducing bias in density estimates for unmarked populations that exhibit reactive behaviour towards camera traps

Methods in Ecology and Evolution, Год журнала: 2023, Номер 14(12), С. 3100 - 3111

Опубликована: Ноя. 14, 2023

Abstract Density estimates guide wildlife management, and camera traps are commonly used to estimate sizes of unmarked populations. Unfortunately, animals often alter their natural behaviour in the presence traps, which may bias subsequent density estimates. We simulated 100 populations known test several new existing methods that aimed reduce from trap distance sampling (CTDS) random encounter model (REM). Within our populations, we introduced different behavioural reactions including attraction towards cameras, freezing when near cameras fleeing cameras. CTDS REM provided with decent coverage confidence intervals (CTDS = 94%, 87%), mean coefficient variation 0.121, 0.071) minimal (root‐mean squared error: 1.336, 0.913) for no reactive behaviour. However, failure implement a method account resulted low coverage, large potentially imprecise 30% population reacted by or traps. identified corrective strategy enhanced interval increased precision reduced every reaction except individuals fled Synthesis applications . provide empirically tested reducing Wildlife managers requiring exhibit can use inaccuracy. encourage future studies quantify responses implement, possibly extend through simulation.

Язык: Английский

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Snow track counts for density estimation of mammalian predators in the boreal forest

Wildlife Research, Год журнала: 2022, Номер 50(6), С. 425 - 434

Опубликована: Окт. 4, 2022

Context Methods for estimating density of meso-carnivores in northern ecosystems are labour intensive and expensive to implement if mark–recapture radio collaring used. One alternative is count tracks the snow along transects as an index density, but this method has been criticised imprecise lacking validation. Aims We aimed examine utility track counts snowmobile trails measuring changes populations Canada lynx coyotes boreal forest north-western Canada. compared winter at three study sites one site with concurrent estimates based on locations radio-collared animals numbers uncollared from 7–9-year studies Yukon Northwest Territories, during a period cyclical population fluctuations. Key results Snow were positively correlated (r2 = 0.83) lynx, estimated by live trapping survey areas. Coyotes also showed clear relationship 0.80) between known counts, strongly affected season, much higher early when was shallower. This indicates need control season or depth using indices coyote abundance. recommend sample sizes least 10 per 25-km transect maximise precision. Conclusions relatively simple, inexpensive concurrently tracking abundance multiple species meso-carnivores. These data indicate that may be reliably used monitor trends numbers, we suggest site-specific validation regressions reported here animal required translate these into density. Implications Track have potential affordable more methods monitoring medium-sized mammals, purposes such management harvest measure success programs increase reduce

Язык: Английский

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Density estimates of unmarked mammals: comparing two models and assumptions across multiple species and years

Canadian Journal of Zoology, Год журнала: 2023, Номер 102(3), С. 286 - 297

Опубликована: Окт. 19, 2023

Density estimation is a key goal in ecology, but accurate estimates for unmarked animals remain elusive. Camera trap data can bridge this gap, accuracy, precision, and concordance varies among estimators. We compared from spatial capture–recapture (spatial count (SC)) models, time front of camera (TIFC) four large mammal species boreal Canada. Species differed movement rates, behaviours, sociality—traits related to model assumptions. TIFC densities typically exceeded SC all species. Two- five-fold differences between estimators were common. annually stable moose caribou not white-tailed deer. showed high annual variation some species, sites, years, consistency others. Both models often produced imprecise estimates. Estimates varied DNA- aerial survey-based contend diverge, or implausibly vary, due violations assumptions incurred by animal behaviour. Gregarious pose challenges SC, whereas curious models. Simulations help unravel the role assumption affecting accuracy estimates, field applications across landscapes interpret outcomes estimating density simulated data.

Язык: Английский

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The importance of independence in unmarked spatial capture–recapture analysis

Wildlife Biology, Год журнала: 2024, Номер 2024(3)

Опубликована: Март 13, 2024

Wildlife populations can be unmarked, meaning individuals lack distinguishing features for individual identification. Populations may also exhibit non‐independent movements, move together. For of either unmarked or individuals, models based on spatial capture–recapture (SCR) approaches used to estimate abundance, density, and other parameters critical monitoring, management, conservation. However, when are both non‐independent, few model options available. One approach has been apply not address the non‐independence despite unquantified impacts bias, precision, ability make robust ecological inferences. We conducted a simulation study quantify impact performance count (SC) partial identity (SPIM) – two SCR‐based modeling fully marked independent SCR as reference. varied levels (aggregation cohesion), detection probability, number covariates resolve identities in SPIM estimation. expected abundance estimates increasingly biased precise aggregation cohesion increased. Results showed that indeed became less increasing non‐independence, but importantly suggested only could reliably applied under low sufficient SC yielded consistently with poor precision. was across combinations cohesion, expected. therefore advise against use estimating population known caution narrow conditions, encourage continued investigations into sampling design methods development individuals.

Язык: Английский

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