560 items found
Type:
Subjects: Aquatic research
Subject:Aquatic research
Description:Bibliography of aquatic research publications, reports, and presentations
Type:
Subjects: Aquatic research
Fisheries management
Fisheries management
Subject:Aquatic research
Fisheries management
Fisheries management
Description:An overview of the Aquatic Research Section and how the researchers use a science-based approach to their work
Type: Article
Subjects: Argos
Bayesian model
Canada lynx
Functional data analysis
Movement modelling
Splines
Telemetry
Bayesian model
Canada lynx
Functional data analysis
Movement modelling
Splines
Telemetry
Type:Article
Subject:Argos
Bayesian model
Canada lynx
Functional data analysis
Movement modelling
Splines
Telemetry
Bayesian model
Canada lynx
Functional data analysis
Movement modelling
Splines
Telemetry
Description:
[show more]
Summary
- Advancements in wildlife telemetry techniques have made it possible to collect large data sets of highly accurate animal locations at a fine temporal resolution. These data sets have prompted the development of a number of statistical methodologies for modelling animal movement.
- Telemetry data sets are often collected for purposes other than fine-scale movement analysis. These data sets may differ substantially from those that are collected with technologies suitable for fine-scale movement modelling and may consist of locations that are irregular in time, are temporally coarse or have large measurement error. These data sets are time-consuming and costly to collect but may still provide valuable information about movement behaviour.
- We developed a Bayesian movement model that accounts for error from multiple data sources as well as movement behaviour at different temporal scales. The Bayesian framework allows us to calculate derived quantities that describe temporally varying movement behaviour, such as residence time, speed and persistence in direction. The model is flexible, easy to implement and computationally efficient.
- We apply this model to data from Colorado Canada lynx (Lynx canadensis) and use derived quantities to identify changes in movement behaviour.
Type: Article
Subjects: Artificial intelligence
Camera trap
Convolutional neural network
Deep neural networks
Image classification
Machine learning
r package
Remote sensing
Camera trap
Convolutional neural network
Deep neural networks
Image classification
Machine learning
r package
Remote sensing
Type:Article
Subject:Artificial intelligence
Camera trap
Convolutional neural network
Deep neural networks
Image classification
Machine learning
r package
Remote sensing
Camera trap
Convolutional neural network
Deep neural networks
Image classification
Machine learning
r package
Remote sensing
Description:
- Motion-activated cameras (“camera traps”) are increasingly used in ecological and management studies for remotely observing wildlife and are amongst the most powerful tools for wildlife research. However, studies involving camera traps result in millions of images that need to be analysed, typically by visually observing each image, in order to extract data that can be used in ecological analyses.
- We trained machine learning models using convolutional neural networks with the ResNet-18 architecture and 3,367,383 images to automatically classify wildlife species from camera trap images obtained from five states across the United States. We tested our model on an independent subset of images not seen during training from the United States and on an out-of-sample (or “out-of-distribution” in the machine learning literature) dataset of ungulate images from Canada. We also tested the ability of our model to distinguish empty images from those with animals in another out-of-sample dataset from Tanzania, containing a faunal community that was novel to the model.
- The trained model classified approximately 2,000 images per minute on a laptop computer with 16 gigabytes of RAM. The trained model achieved 98% accuracy at identifying species in the United States, the highest accuracy of such a model to date. Out-of-sample validation from Canada achieved 82% accuracy and correctly identified 94% of images containing an animal in the dataset from Tanzania. We provide an r package (Machine Learning for Wildlife Image Classification) that allows the users to (a) use the trained model presented here and (b) train their own model using classified images of wildlife from their studies.
- The use of machine learning to rapidly and accurately classify wildlife in camera trap images can facilitate non-invasive sampling designs in ecological studies by reducing the burden of manually analysing images. Our r package makes these methods accessible to ecologists.
Type: Article
Subjects: Aural detections
Availability process
Avian point counts
Detection probability
Field tests
Perception process
Time-of-detection method
Availability process
Avian point counts
Detection probability
Field tests
Perception process
Time-of-detection method
Type:Article
Subject:Aural detections
Availability process
Avian point counts
Detection probability
Field tests
Perception process
Time-of-detection method
Availability process
Avian point counts
Detection probability
Field tests
Perception process
Time-of-detection method
Description:The time-of-detection method for aural avian point counts is a new method of estimating abundance, allowing for uncertain probability of detection. The method has been specifically designed to allow for variation in singing rates of birds. It involves dividing the time interval of the point count into several subintervals and recording the detection history of the subintervals when each bird sings. The method can be viewed as generating data equivalent to closed capture–recapture information. The method is different from the distance and multiple-observer methods in that it is not required that all the birds sing during the point count. As this method is new and there is some concern as to how well individual birds can be followed, we carried out a field test of the method using simulated known populations of singing birds, using a laptop computer to send signals to audio stations distributed around a point. The system mimics actual aural avian point counts, but also allows us to know the size and spatial distribution of the populations we are sampling. Fifty 8-min point counts (broken into four 2-min intervals) using eight species of birds were simulated. Singing rate of an individual bird of a species was simulated following a Markovian process (singing bouts followed by periods of silence), which we felt was more realistic than a truly random process. The main emphasis of our paper is to compare results from species singing at (high and low) homogenous rates per interval with those singing at (high and low) heterogeneous rates. Population size was estimated accurately for the species simulated, with a high homogeneous probability of singing. Populations of simulated species with lower but homogeneous singing probabilities were somewhat underestimated. Populations of species simulated with heterogeneous singing probabilities were substantially underestimated. Underestimation was caused by both the very low detection probabilities of all distant individuals and by individuals with low singing rates also having very low detection probabilities. [show more]
Type: Article
Subjects: Autocorrelation
GPS radio telemetry
Resource selection function (RSF)
Spatial point process
Species distribution model
Use–availability data
Wildlife
GPS radio telemetry
Resource selection function (RSF)
Spatial point process
Species distribution model
Use–availability data
Wildlife
Type:Article
Subject:Autocorrelation
GPS radio telemetry
Resource selection function (RSF)
Spatial point process
Species distribution model
Use–availability data
Wildlife
GPS radio telemetry
Resource selection function (RSF)
Spatial point process
Species distribution model
Use–availability data
Wildlife
Description:Habitat selection is a fundamental aspect of animal ecology, the understanding of which is critical to management and conservation. Global positioning system data from animals allow fine-scale assessments of habitat selection and typically are analyzed in a use–availability framework, whereby animal locations are contrasted with random locations (the availability sample). Although most use–availability methods are in fact spatial point process models, they often are fit using logistic regression. This framework offers numerous methodological challenges, for which the literature provides little guidance. Specifically, the size and spatial extent of the availability sample influences coefficient estimates potentially causing interpretational bias. We examined the influence of availability on statistical inference through simulations and analysis of serially correlated mule deer GPS data. Bias in estimates arose from incorrectly assessing and sampling the spatial extent of availability. Spatial autocorrelation in covariates, which is common for landscape characteristics, exacerbated the error in availability sampling leading to increased bias. These results have strong implications for habitat selection analyses using GPS data, which are increasingly prevalent in the literature. We recommend that researchers assess the sensitivity of their results to their availability sample and, where bias is likely, take care with interpretations and use cross validation to assess robustness. [show more]
Type: Article
Subjects: Automated
Baiting
Capture
Capture techniques
Collaring
Fawn
Handling
Mule deer
Noninvasive
<em>Odocoileus hemionus</em>
Baiting
Capture
Capture techniques
Collaring
Fawn
Handling
Mule deer
Noninvasive
<em>Odocoileus hemionus</em>
Type:Article
Subject:Automated
Baiting
Capture
Capture techniques
Collaring
Fawn
Handling
Mule deer
Noninvasive
<em>Odocoileus hemionus</em>
Baiting
Capture
Capture techniques
Collaring
Fawn
Handling
Mule deer
Noninvasive
<em>Odocoileus hemionus</em>
Description:Wildlife biologists capture deer (Odocoileus spp.) annually to attach transmitters and collect basic information (e.g., animal mass and sex) as part of ongoing research and monitoring activities. Traditional capture techniques induce stress in animals and can be expensive, inefficient, and dangerous. They are also impractical for some urbanized settings. We designed and evaluated a device for mule deer (O. hemionus) that automatically attached an expandable radiocollar to a ≥6-month-old fawn and recorded the fawn's mass and sex, without physically restraining the animal. The device did not require on-site human presence to operate. Students and faculty in the Mechanical Engineering Department at Colorado State University produced a conceptual model and early prototype. Professional engineers at Dynamic Group Circuit Design, Inc. in Fort Collins, Colorado, USA, produced a fully functional prototype of the device. Using the device, we remotely collared, weighed, and identified sex of 8 free-ranging mule deer fawns during winters 2010–2011 and 2011–2012. Collars were modified to shed from deer approximately 1 month after the collaring event. Two fawns were successfully recollared after they shed the first collars they received. Thus, we observed 10 successful collaring events involving 8 unique fawns. Fawns demonstrated minimal response to collaring events, either remaining in the device or calmly exiting. A fawn typically required ≥1 weeks of daily exposure before fully entering the device and extending its head through the outstretched collar, which was necessary for a collaring event to occur. This slow acclimation period limited utility of the device when compared with traditional capture techniques. Future work should focus on device modifications and altered baiting strategies that decrease fawn acclimation period, and in turn, increase collaring rates, providing a noninvasive and perhaps cost-effective alternative for monitoring mid- to large-sized mammal species. [show more]
Type: Article
Subjects: Aversive conditioning
Colorado
Conflict
Cougar
Domestic predation
Human interaction
Livestock, predation
<em>Puma concolor</em>
Residential development
Wildland–urban interface
Colorado
Conflict
Cougar
Domestic predation
Human interaction
Livestock, predation
<em>Puma concolor</em>
Residential development
Wildland–urban interface
Type:Article
Subject:Aversive conditioning
Colorado
Conflict
Cougar
Domestic predation
Human interaction
Livestock, predation
<em>Puma concolor</em>
Residential development
Wildland–urban interface
Colorado
Conflict
Cougar
Domestic predation
Human interaction
Livestock, predation
<em>Puma concolor</em>
Residential development
Wildland–urban interface
Description:As human populations continue to expand across the world, the need to understand and manage wildlife populations within the wildland–urban interface is becoming commonplace. This is especially true for large carnivores as these species are not always tolerated by the public and can pose a risk to human safety. Unfortunately, information on wildlife species within the wildland–urban interface is sparse, and knowledge from wildland ecosystems does not always translate well to human-dominated systems. Across western North America, cougars (Puma concolor) are routinely utilizing wildland–urban habitats while human use of these areas for homes and recreation is increasing. From 2007 to 2015, we studied cougar resource selection, human–cougar interaction, and cougar conflict management within the wildland–urban landscape of the northern Front Range in Colorado, USA. Resource selection of cougars within this landscape was typical of cougars in more remote settings but cougar interactions with humans tended to occur in locations cougars typically selected against, especially those in proximity to human structures. Within higher housing density areas, 83% of cougar use occurred at night, suggesting cougars generally avoided human activity by partitioning time. Only 24% of monitored cougars were reported for some type of conflict behavior but 39% of cougars sampled during feeding site investigations of GPS collar data were found to consume domestic prey items. Aversive conditioning was difficult to implement and generally ineffective for altering cougar behaviors but was thought to potentially have long-term benefits of reinforcing fear of humans in cougars within human-dominated areas experiencing little cougar hunting pressure. Cougars are able to exploit wildland–urban landscapes effectively, and conflict is relatively uncommon compared with the proportion of cougar use. Individual characteristics and behaviors of cougars within these areas are highly varied; therefore, conflict management is unique to each situation and should target individual behaviors. The ability of individual cougars to learn to exploit these environments with minimal human–cougar interactions suggests that maintaining older age structures, especially females, and providing a matrix of habitats, including large connected open-space areas, would be beneficial to cougars and effectively reduce the potential for conflict. [show more]
Type: Article
Subjects: Avian occupancy
Mastication
Piñon–juniper
Pinyon pine
Treatments
Woodland birds
Mastication
Piñon–juniper
Pinyon pine
Treatments
Woodland birds
Type:Article
Subject:Avian occupancy
Mastication
Piñon–juniper
Pinyon pine
Treatments
Woodland birds
Mastication
Piñon–juniper
Pinyon pine
Treatments
Woodland birds
Description:Natural resource managers are increasingly applying tree reduction treatments to piñon–juniper woodlands to meet a range of ecological, social, and economic goals. However, treatment effects on woodland-obligate bird species are not well understood. We measured multiscale avian occupancy on 29 paired (control/treatment) sites in piñon–juniper woodlands in central Colorado, USA. We conducted point counts at 232 stations, 3 times each season in 2014 and 2015. We used hierarchical multiscale modeling to obtain unbiased estimates of landscape and local occupancy (i.e. probability of use) in treated and untreated sites for 31 species. Treatments reduced the occupancy of conifer obligates, including Mountain Chickadee (Poecile gambeli), Clark’s Nutcracker (Nucifraga columbiana), and White-breasted Nuthatch (Sitta carolinensis), and increased occupancy of Lark Sparrow (Chondestes grammacus) and Mountain Bluebird (Sialia currucoides). Occupancy of Virginia’s Warbler (Oreothylpis virginiae) and Gray Flycatcher (Empidonax wrightii), two piñon–juniper specialists, decreased at the landscape scale in treated sites, and Pinyon Jay (Gymnorhinus cyanocephalus) occupancy decreased at the local scale. Tree reduction treatments in piñon–juniper woodlands have the potential to reduce habitat quality for a suite of bird species of conservation concern. We suggest that treatments designed to retain higher tree density and basal area will benefit conifer-obligate and piñon–juniper specialist bird species.Los gestores de los recursos naturales aplican cada vez con mayor frecuencia tratamientos de raleo de árboles a los bosques de piñón y enebro para alcanzar una serie de objetivos ecológicos, sociales y económicos. Sin embargo, no se comprenden claramente los efectos de los tratamientos para las especies de aves que habitan de forma obligada en los bosques. Medimos la ocupación de las aves a múltiples escalas en 29 sitios pareados (control/tratamiento) en bosques de piñón y enebro en el centro de Colorado, EEUU. Realizamos conteos en puntos en 232 lugares, tres veces en cada estación en 2014 y 2015. Usamos modelos jerárquicos a escalas múltiples para obtener estimaciones no sesgadas de ocupación (i.e. probabilidad de uso) a escala de paisaje y local en sitios tratados y no tratados para 31 especies. Los tratamientos redujeron la ocupación de las especies que habitan en forma obligada los bosques de coníferas, incluyendo a Poecile gambeli, Nucifraga columbiana y Sitta carolinensis; y aumentaron la ocupación de Chondestes grammacus y Sialia currucoides. La ocupación de Oreothylpis virginiae y Empidonax wrightii, dos especialistas de los bosques de piñón y enebro, disminuyó a la escala de paisaje en los sitios tratados, y la ocupación de Gymnorhinus cyanocephalus disminuyó a escala local. Tres tratamientos de raleo de los bosques de piñón y enebro tienen el potencial de reducir la calidad de hábitat para un grupo de especies de aves de interés para la conservación. Sugerimos que los tratamientos diseñados para retener mayor diversidad de árboles y área basal beneficiarán a las especies de aves que habitan de forma obligada los bosques de coníferas y a las especialistas de piñón y enebro. [show more]
Type: Article
Subjects: Backcountry skiing
Colorado
Dispersed recreation
Functional response
Habitat selection
Heliskiing
<em>Lynx canadensis</em>
Outdoor recreation
Resource-selection functions
Snowmobiling
Winter recreation
Colorado
Dispersed recreation
Functional response
Habitat selection
Heliskiing
<em>Lynx canadensis</em>
Outdoor recreation
Resource-selection functions
Snowmobiling
Winter recreation
Type:Article
Subject:Backcountry skiing
Colorado
Dispersed recreation
Functional response
Habitat selection
Heliskiing
<em>Lynx canadensis</em>
Outdoor recreation
Resource-selection functions
Snowmobiling
Winter recreation
Colorado
Dispersed recreation
Functional response
Habitat selection
Heliskiing
<em>Lynx canadensis</em>
Outdoor recreation
Resource-selection functions
Snowmobiling
Winter recreation
Description:Outdoor recreationists are important advocates for wildlife on public lands. However, balancing potential impacts associated with increased human disturbance with the conservation of sensitive species is a central issue facing ecologists and land managers alike, especially for dispersed winter recreation due to its disproportionate impact to wildlife. We studied how dispersed winter recreation (outside developed ski areas) impacted a reintroduced meso-carnivore, Canada lynx (Lynx canadensis), at the southern periphery of the species’ range in the southern Rocky Mountains. On a voluntary basis, we distributed global positioning system (GPS) units to winter recreationists and documented 2143 spatial movement tracks of recreationists engaged in motorized and nonmotorized winter sports for a total cumulative distance of 56,000 km from 2010 to 2013. We also deployed GPS radio collars on adult Canada lynx that were resident in the mountainous topography that attracted high levels of dispersed winter recreation. We documented that resource-selection models (RSFs) for Canada lynx were significantly improved when selection patterns of winter recreationists were included in best-performing models. Canada lynx and winter recreationists partitioned environmental gradients in ways that reduced the potential for recreation-related disturbance. Although the inclusion of recreation improved the RSF model for Canada lynx, environmental covariates explained most variation in resource use. The environmental gradients that most separated areas selected by Canada lynx from those used by recreationists were forest canopy closure, road density, and slope. Canada lynx also exhibited a functional response of increased avoidance of areas selected by motorized winter recreationists (snowmobiling off-trail, hybrid snowmobile) compared with either no functional response (hybrid ski) or selection for (backcountry skiing) areas suitable for nonmotorized winter recreation. We conclude with a discussion of implications associated with providing winter recreation balanced with the conservation of Canada lynx. [show more]