115 research outputs found
An empirical evaluation of camera trap study design: How many, how long and when?
Abstract
Camera traps deployed in grids or stratified random designs are a wellâestablished survey tool for wildlife but there has been little evaluation of study design parameters.
We used an empirical subsampling approach involving 2,225 camera deployments run at 41 study areas around the world to evaluate three aspects of camera trap study design (number of sites, duration and season of sampling) and their influence on the estimation of three ecological metrics (species richness, occupancy and detection rate) for mammals.
We found that 25â35 camera sites were needed for precise estimates of species richness, depending on scale of the study. The precision of speciesâlevel estimates of occupancy (Ï) was highly sensitive to occupancy level, with 0.75) species, but more than 150 camera sites likely needed for rare (Ï < 0.25) species. Species detection rates were more difficult to estimate precisely at the grid level due to spatial heterogeneity, presumably driven by unaccounted habitat variability factors within the study area. Running a camera at a site for 2 weeks was most efficient for detecting new species, but 3â4 weeks were needed for precise estimates of local detection rate, with no gains in precision observed after 1 month. Metrics for all mammal communities were sensitive to seasonality, with 37%â50% of the species at the sites we examined fluctuating significantly in their occupancy or detection rates over the year. This effect was more pronounced in temperate sites, where seasonally sensitive species varied in relative abundance by an average factor of 4â5, and some species were completely absent in one season due to hibernation or migration.
We recommend the following guidelines to efficiently obtain precise estimates of species richness, occupancy and detection rates with camera trap arrays: run each camera for 3â5 weeks across 40â60 sites per array. We recommend comparisons of detection rates be model based and include local covariates to help account for smallâscale variation. Furthermore, comparisons across study areas or times must account for seasonality, which could have strong impacts on mammal communities in both tropical and temperate sites
SNAPSHOT USA 2019: a coordinated national camera trap survey of the United States
With the accelerating pace of global change, it is imperative that we obtain rapid inventories of the status and distribution of wildlife for ecological inferences and conservation planning. To address this challenge, we launched the SNAPSHOT USA project, a collaborative survey of terrestrial wildlife populations using camera traps across the United States. For our first annual survey, we compiled data across all 50 states during a 14-week period (17 August-24 November of 2019). We sampled wildlife at 1,509 camera trap sites from 110 camera trap arrays covering 12 different ecoregions across four development zones. This effort resulted in 166,036 unique detections of 83 species of mammals and 17 species of birds. All images were processed through the Smithsonian's eMammal camera trap data repository and included an expert review phase to ensure taxonomic accuracy of data, resulting in each picture being reviewed at least twice. The results represent a timely and standardized camera trap survey of the United States. All of the 2019 survey data are made available herein. We are currently repeating surveys in fall 2020, opening up the opportunity to other institutions and cooperators to expand coverage of all the urban-wild gradients and ecophysiographic regions of the country. Future data will be available as the database is updated at eMammal.si.edu/snapshot-usa, as will future data paper submissions. These data will be useful for local and macroecological research including the examination of community assembly, effects of environmental and anthropogenic landscape variables, effects of fragmentation and extinction debt dynamics, as well as species-specific population dynamics and conservation action plans. There are no copyright restrictions; please cite this paper when using the data for publication
Ape Conservation Physiology: Fecal Glucocorticoid Responses in Wild Pongo pygmaeus morio following Human Visitation
Nature-based tourism can generate important revenue to support conservation of biodiversity. However, constant exposure to tourists and subsequent chronic activation of stress responses can produce pathological effects, including impaired cognition, growth, reproduction, and immunity in the same animals we are interested in protecting. Utilizing fecal samples (Nâ=â53) from 2 wild habituated orangutans (Pongo pygmaeus morio) (in addition to 26 fecal samples from 4 wild unhabituated orangutans) in the Lower Kinabatangan Wildlife Sanctuary of Sabah, Malaysian Borneo, we predicted that i) fecal glucocorticoid metabolite concentrations would be elevated on the day after tourist visitation (indicative of normal stress response to exposure to tourists on the previous day) compared to samples taken before or during tourist visitation in wild, habituated orangutans, and ii) that samples collected from habituated animals would have lower fecal glucocorticoid metabolites than unhabituated animals not used for tourism. Among the habituated animals used for tourism, fecal glucocorticoid metabolite levels were significantly elevated in samples collected the day after tourist visitation (indicative of elevated cortisol production on the previous day during tourist visitation). Fecal glucocorticoid metabolite levels were also lower in the habituated animals compared to their age-matched unhabituated counterparts. We conclude that the habituated animals used for this singular ecotourism project are not chronically stressed, unlike other species/populations with documented permanent alterations in stress responses. Animal temperament, species, the presence of coping/escape mechanisms, social confounders, and variation in amount of tourism may explain differences among previous experiments. Acute alterations in glucocorticoid measures in wildlife exposed to tourism must be interpreted conservatively. While permanently altered stress responses can be detrimental, preliminary results in these wild habituated orangutans suggest that low levels of predictable disturbance can likely result in low physiological impact on these animals
Effects of fecal age and seasonality on steroid hormone concentration as a reproductive parameter in field studies
SNAPSHOT USA 2019 : a coordinated national camera trap survey of the United States
This article is protected by copyright. All rights reserved.With the accelerating pace of global change, it is imperative that we obtain rapid inventories of the status and distribution of wildlife for ecological inferences and conservation planning. To address this challenge, we launched the SNAPSHOT USA project, a collaborative survey of terrestrial wildlife populations using camera traps across the United States. For our first annual survey, we compiled data across all 50 states during a 14-week period (17 August - 24 November of 2019). We sampled wildlife at 1509 camera trap sites from 110 camera trap arrays covering 12 different ecoregions across four development zones. This effort resulted in 166,036 unique detections of 83 species of mammals and 17 species of birds. All images were processed through the Smithsonian's eMammal camera trap data repository and included an expert review phase to ensure taxonomic accuracy of data, resulting in each picture being reviewed at least twice. The results represent a timely and standardized camera trap survey of the USA. All of the 2019 survey data are made available herein. We are currently repeating surveys in fall 2020, opening up the opportunity to other institutions and cooperators to expand coverage of all the urban-wild gradients and ecophysiographic regions of the country. Future data will be available as the database is updated at eMammal.si.edu/snapshot-usa, as well as future data paper submissions. These data will be useful for local and macroecological research including the examination of community assembly, effects of environmental and anthropogenic landscape variables, effects of fragmentation and extinction debt dynamics, as well as species-specific population dynamics and conservation action plans. There are no copyright restrictions; please cite this paper when using the data for publication.Publisher PDFPeer reviewe
Fecal Glucocorticoid Metabolites as Biomarkers in Equids: Assay Choice Matters
From Wiley via Jisc Publications RouterHistory: received 2020-05-06, rev-recd 2021-03-29, accepted 2021-04-09, pub-electronic 2021-06-01Article version: VoRPublication status: PublishedFunder: Royal Society; Id: http://dx.doi.org/10.13039/501100000288; Grant(s): UF110641Funder: Chester Zoo; Id: http://dx.doi.org/10.13039/501100005359; Grant(s): Conservation FellowshipABSTRACT: Free ranging animals are exposed to environmental, demographic, and ecological challenges over time, which can affect their health and fitness. Nonâinvasive biomarkers can provide insight into how animals cope with these challenges and assess the effectiveness of conservation management strategies. We evaluated how free ranging ponies (Equus ferus caballus) on the Carneddau Mountain range, North Wales respond to 2 stimuli: an acute stressor of an annual roundup event in November 2014, and spatial and temporal variation in ecological factors in 2018. We evaluated fecal glucocorticoid metabolites using 2 enzyme immunoassays (EIAs): an 11âoxoetiocholanolone EIA (measuring 11,17âdioxoandrostanes [11,17âDOAs]) and a corticosterone EIA. The former assay has been validated in equids, whereas there is limited evidence for the suitability of the latter. We used an additional parent testosterone EIA to measure fecal androgen metabolites in response to the ecological challenges. Following the roundup, the metabolite concentrations measured by the 2 glucocorticoid EIAs were not correlated. The 11,17âDOAs were elevated from the second day following the roundup and then slowly returned to preâround levels over the next 2 weeks. In contrast, the metabolites measured by the corticosterone assay showed no response to the roundup. For the ecological data, all 3 assays detected a positive correlation between metabolites and social group size in males but not in females. The metabolite concentrations measured by the testosterone and corticosterone assays were highly correlated and were temporally associated with the onset of the breeding season, whereas the 11,17âDOAs were not. The coâvariance of metabolites measured by the corticosterone and testosterone assays, and the lack of an acute response in the corticosterone assay to the roundup, suggests that metabolites detected by the corticosterone assay were not primarily associated with increased glucocorticoid production. We recommend using wellâvalidated fecal biomarker assays of hypothalamusâpituitaryâadrenal axis activity to evaluate and compare the effect of different management interventions and environmental change. © 2021 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society
Mammal responses to global changes in human activity vary by trophic group and landscape
Wildlife must adapt to human presence to survive in the Anthropocene, so it is critical to understand species responses to humans in different contexts. We used camera trapping as a lens to view mammal responses to changes in human activity during the COVID-19 pandemic. Across 163 species sampled in 102 projects around the world, changes in the amount and timing of animal activity varied widely. Under higher human activity, mammals were less active in undeveloped areas but unexpectedly more active in developed areas while exhibiting greater nocturnality. Carnivores were most sensitive, showing the strongest decreases in activity and greatest increases in nocturnality. Wildlife managers must consider how habituation and uneven sensitivity across species may cause fundamental differences in humanâwildlife interactions along gradients of human influence.Peer reviewe
Inter-individual variability of stone marten behavioral responses to a highway
Efforts to reduce the negative impacts of roads on wildlife may be hindered if individuals within the population vary widely
in their responses to roads and mitigation strategies ignore this variability. This knowledge is particularly important for
medium-sized carnivores as they are vulnerable to road mortality, while also known to use available road passages (e.g.,
drainage culverts) for safely crossing highways. Our goal in this study was to assess whether this apparently contradictory
pattern of high road-kill numbers associated with a regular use of road passages is attributable to the variation in behavioral
responses toward the highway between individuals. We investigated the responses of seven radio-tracked stone martens
(Martes foina) to a highway by measuring their utilization distribution, response turning angles and highway crossing
patterns. We compared the observed responses to simulated movement parameterized by the observed space use and
movement characteristics of each individual, but naıšve to the presence of the highway. Our results suggested that martens
demonstrate a diversity of responses to the highway, including attraction, indifference, or avoidance. Martens also varied in
their highway crossing patterns, with some crossing repeatedly at the same location (often coincident with highway
passages). We suspect that the response variability derives from the individualâs familiarity of the landscape, including their
awareness of highway passage locations. Because of these variable yet potentially attributable responses, we support the
use of exclusionary fencing to guide transient (e.g., dispersers) individuals to existing passages to reduce the road-kill risk
Individual, social, and environmental factors affecting salivary and fecal cortisol levels in captive pied tamarins (Saguinus bicolor)
This is the peer reviewed version of the following article: Price, E., Coleman, R., Ahsmann, J., Glendewar, G., Hunt, J., Smith, T. & Wormell, D. (2019). Individual, social, and environmental factors affecting salivary and fecal cortisol levels in captive pied tamarins (Saguinus bicolor). American Journal of Primatology, 81(8), which has been published in final form at https://doi.org/10.1002/ajp.23033. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-ArchivingPied tamarins (Saguinus bicolor) are endangered New World primates, and in captivity
appear to be very susceptible to stress. We measured cortisol in 214 saliva samples
from 36 tamarins and in 227 fecal samples from 27 tamarins, and investigated
the effects of age, sex, pregnancy, rearing history, social status, weight, group
composition, and enclosure type using generalized linear mixed models. There was no
effect of age on either fecal or salivary cortisol levels. Female pied tamarins in late
pregnancy had higher fecal cortisol levels than those in early pregnancy, or
nonpregnant females, but there was no effect of pregnancy on salivary cortisol.
Females had higher salivary cortisol levels than males, but there was no effect of
rearing history. However, for fecal cortisol, there was an interaction between sex and
rearing history. Handâreared tamarins overall had higher fecal cortisol levels, but
while male parentâreared tamarins had higher levels than females who were parentâ
reared, the reverse was true for handâreared individuals. There was a trend towards
lower fecal cortisol levels in subordinate individuals, but no effect of status on
salivary cortisol. Fecal but not salivary cortisol levels declined with increasing weight.
We found little effect of group composition on cortisol levels in either saliva or feces,
suggesting that as long as tamarins are housed socially, the nature of the group is of
less importance. However, animals in offâshow enclosures had higher salivary and
fecal cortisol levels than individuals housed onâshow. We suggest that large onâshow
enclosures with permanent access to offâexhibit areas may compensate for the
effects of visitor disturbance, and a larger number of tamarins of the same species
housed close together may explain the higher cortisol levels found in tamarins living
in offâshow accommodation, but further research is needed
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