A5000533321- Wildlife Ecology and Conservation
- Marine animal studies overview
- Census and Population Estimation
- Marine and fisheries research
- Fish Ecology and Management Studies
- Avian ecology and behavior
- Animal Ecology and Behavior Studies
- Species Distribution and Climate Change
- Arctic and Antarctic ice dynamics
- Rangeland and Wildlife Management
- Bayesian Methods and Mixture Models
- Genetic and phenotypic traits in livestock
- Survey Sampling and Estimation Techniques
- Animal Vocal Communication and Behavior
- Isotope Analysis in Ecology
- Marine Bivalve and Aquaculture Studies
- Underwater Acoustics Research
- Wildlife-Road Interactions and Conservation
- Data-Driven Disease Surveillance
- Ecology and Vegetation Dynamics Studies
- Statistical Methods and Bayesian Inference
- Economic and Environmental Valuation
- Marine and coastal plant biology
- Rangeland Management and Livestock Ecology
- Cryospheric studies and observations
University of St Andrews
2015-2024
University of Cape Town
2022-2024
Humboldt-Universität zu Berlin
2024
Grønlands Naturinstitut
2023
University of Edinburgh
2016-2017
University of Science and Technology
2017
NOAA National Marine Fisheries Service
2017
NOAA National Marine Fisheries Service Southwest Fisheries Science Center
2017
Norwegian University of Science and Technology
2017
Cree (China)
2014
Live-trapping capture-recapture studies of animal populations with fixed trap locations inevitably have a spatial component: animals close to traps are more likely be caught than those far away. This is not addressed in conventional closed-population estimates abundance and without the component, rigorous density cannot obtained. We propose new, flexible models that use capture estimate spatially referenced probability. The likelihood-based hence allow Akaike's information criterion or other...
Summary The status of small cetaceans in the North Sea and adjacent waters has been concern for many years. Shipboard aerial line transect surveys were conducted to provide accurate precise estimates abundance as a basis conservation strategy European waters. survey, known SCANS (Small Cetacean Abundance Sea), was summer 1994 designed generate unbiased estimates. Thus intensity survey high, data collection analysis methods allowed probability detection animals on being less than unity and,...
The European Union (EU) Habitats Directive requires Member States to monitor and maintain at favourable conservation status those species identified be in need of protection, including all cetaceans. In July 2005 we surveyed the entire EU Atlantic continental shelf generate robust estimates abundance for harbour porpoise other cetacean species. survey used line transect sampling methods purpose built data collection equipment designed minimise bias abundance. Shipboard transects covered...
Abstract Spatial processes are central to many ecological processes, but fitting models that incorporate spatial correlation data from surveys is computationally challenging. This particularly true of point pattern (in which the primary locations at target species found), also gridded data, and georeferenced samples continuous fields. We describe here R package inlabru builds on widely used RINLA provide easier access Bayesian inference process, count, gridded, using integrated nested...
Summary Accurate and precise estimates of abundance are required for the development management regimes deer populations. In woodland areas, indirect dung count methods, such as clearance plot standing crop currently preferred procedures to estimate abundance. The use line transect methodology is likely provide a cost‐effective alternative these methods. We outline based on surveys that can be used obtain by geographical block habitat type. Variance estimation also described. As an example,...
The density of a closed population animals occupying stable home ranges may be estimated from detections individuals on an array detectors, using newly developed methods for spatially explicit capture-recapture. Likelihood-based provide estimates data multi-catch traps or devices that record presence without restricting animal movement ("proximity" detectors such as camera and hair snags). As originally proposed, these require multiple sampling intervals. We show equally precise unbiased...
Summary Mark‐recapture models applied to double‐observer distance sampling data neglect the information on relative detectability of objects contained in distribution observed distances. A difference between and that predicted by mark‐recapture model is symptomatic a failure assumption zero correlation detection probabilities implicit model. We develop mark‐recapture‐based uses relax this at only one distance. demonstrate its usefulness coping with unmodeled heterogeneity using from an...
The dominant source of variance in line transect sampling is usually the encounter rate variance. Systematic survey designs are often used to reduce true variability among different realizations design, but estimating difficult and estimators typically approximate by treating design as a simple random sample lines. We explore properties under systematic designs. show that design-based estimator improves upon model-based Buckland et al. (2001, Introduction Distance Sampling. Oxford: Oxford...
Summary Acoustic monitoring can be an efficient, cheap, non‐invasive alternative to physical trapping of individuals. Spatially explicit capture–recapture (SECR) methods have been proposed estimate calling animal abundance and density from data collected by a fixed array microphones. However, these make some assumptions that are unlikely hold in many situations, the consequences violating yet investigated. We generalize existing acoustic SECR methodology, enabling used much wider variety...
Distance sampling is a widely used method for estimating wildlife population abundance. The fact that conventional distance methods are partly design-based constrains the spatial resolution at which animal density can be estimated using these methods. Estimates usually obtained survey stratum level. For an endangered species such as blue whale, it desirable to estimate and abundance finer scale than stratum. Temporal variation in structure also important. We formulate process generating data...
Aerial line transect surveys of the density humpback whales (Megaptera novaeangliae) conducted off West Greenland eight times between 1984 and 2007 were used to estimate rate increase on summer feeding ground. Only in 1993, 2005 had enough sightings construct independent estimates, whereas 1984–85 1987–89 be merged treated as two surveys. The annual was 9.4% yr–1 (SE = 0.01) 2007. This is higher than estimated at breeding grounds Indies, but same magnitude observed other North Atlantic. A...
SUMMARY One of the key assumptions conventional line transect (LT) theory is that all animals in observer's path are detected. When this assumption fails, simultaneous survey by two independent observers can be used to estimate detection probabilities and abundance. Models developed for such surveys both grouped ungrouped perpendicular distance data. The models unify generalize existing mark-recapture models. They provide a general framework estimation abundance from LT which on trackline...
SUMMARY Horvitz-Thompson estimators based on estimated inclusion probabilities are developed for line transect surveys in which some of the central assumptions conventional theory fail. The designed to accommodate uncertain detection animals observers' path simultaneously with dependence explanatory variables other than perpendicular distance. They require that data be collected by two observer teams searching survey region, recording each both positional and details any may affect...
Summary Interest in surveys for monitoring plant abundance is increasing, due part to the need quantify rate of loss biodiversity. Line transect sampling offers an efficient way monitor many species. However, method does not work well some circumstances, example on small survey plots, when species has a strongly aggregated distribution, or plants that are line easily detected. We develop crossed design, together with methods exploit additional information from such address these problems....
Summary Mark–recapture distance sampling ( MRDS ) methods are widely used for density and abundance estimation when the conventional DS assumption of certain detection at zero fails, as they allow to be estimated incorporated into overall probability better estimate abundance. However, incorporating MR data in models raises survey analysis issues not present . Conversely, assumptions As a result, being familiar with either or does on its own put practitioners good position apply...