Resolving issues of imprecise and habitat-biased locations in ecological analyses using GPS telemetry data

Global positioning system (GPS) technologies collect unprecedented volumes of animal location data, providing ever greater insight into animal behaviour. Despite a certain degree of inherent imprecision and bias in GPS locations, little synthesis regarding the predominant causes of these errors, their implications for ecological analysis or solutions exists. Terrestrial deployments report 37 per cent or less non-random data loss and location precision 30 m or less on average, with canopy closure having the predominant effect, and animal behaviour interacting with local habitat conditions to affect errors in unpredictable ways. Home-range estimates appear generally robust to contemporary levels of location imprecision and bias, whereas movement paths and inferences of habitat selection may readily become misleading. There is a critical need for greater understanding of the additive or compounding effects of location imprecision, fix-rate bias, and, in the case of resource selection, map error on ecological insights. Technological advances will help, but at present analysts have a suite of ad hoc statistical corrections and modelling approaches available—tools that vary greatly in analytical complexity and utility. The success of these solutions depends critically on understanding the error-inducing mechanisms, and the biggest gap in our current understanding involves species-specific behavioural effects on GPS performance.

[1]  Horst Bornemann,et al.  All at sea with animal tracks; methodological and analytical solutions for the resolution of movement , 2007 .

[2]  Chris J. Johnson,et al.  A MULTISCALE BEHAVIORAL APPROACH TO UNDERSTANDING THE MOVEMENTS OF WOODLAND CARIBOU , 2002 .

[3]  Vilis O. Nams,et al.  Effects of radiotelemetry error on sample size and bias when testing for habitat selection , 1989 .

[4]  F. Cagnacci,et al.  Animal ecology meets GPS-based radiotelemetry: a perfect storm of opportunities and challenges , 2010, Philosophical Transactions of the Royal Society B: Biological Sciences.

[5]  Sandro Lovari,et al.  Effects of sampling regime on the mean and variance of home range size estimates. , 2006, The Journal of animal ecology.

[6]  Eon,et al.  Effects of a stationary GPS fix-rate BIAS on habitat-selection analyses , 2003 .

[7]  C. Brooks,et al.  Effects of Global Positioning System Collar Weight on Zebra Behavior and Location Error , 2008 .

[8]  Eugene D. Ungar,et al.  Inference of Animal Activity From GPS Collar Data on Free-Ranging Cattle , 2005 .

[9]  P. Fresquez,et al.  Relationship between home range characteristics and the probability of obtaining successful global positioning system (GPS) collar positions for elk in New Mexico , 2001 .

[10]  J. Wickham,et al.  Thematic accuracy of the 1992 National Land-Cover Data for the eastern United States: Statistical methodology and regional results , 2003 .

[11]  O. Ovaskainen,et al.  State-space models of individual animal movement. , 2008, Trends in ecology & evolution.

[12]  P. Krausman,et al.  Influence of topography and GPS fix interval on GPS collar performance , 2005 .

[13]  Stanley M Tomkiewicz,et al.  Global positioning system and associated technologies in animal behaviour and ecological research , 2010, Philosophical Transactions of the Royal Society B: Biological Sciences.

[14]  Kaarina Kauhala,et al.  Radio location error and the estimates of home-range size, movements, and habitat use: a simple field test , 2002 .

[15]  J. Fryxell,et al.  Are there general mechanisms of animal home range behaviour? A review and prospects for future research. , 2008, Ecology letters.

[16]  B. Patterson,et al.  Effects of Variable Sampling Frequencies on GPS Transmitter Efficiency and Estimated Wolf Home Range Size and Movement Distance , 2006 .

[17]  Arthur R. Rodgers,et al.  PERFORMANCE OF A GPS ANIMAL LOCATION SYSTEM UNDER BOREAL FOREST CANOPY , 1995 .

[18]  Monica G. Turner,et al.  Scale and heterogeneity in habitat selection by elk in Yellowstone National Park , 2003 .

[19]  M. Hebblewhite,et al.  Are All Global Positioning System Collars Created Equal? Correcting Habitat-Induced Bias Using Three Brands in the Central Canadian Rockies , 2007 .

[20]  Mark S Boyce,et al.  Correlation and studies of habitat selection: problem, red herring or opportunity? , 2010, Philosophical Transactions of the Royal Society B: Biological Sciences.

[21]  Tabitha A. Graves,et al.  Understanding the Causes of Missed Global Positioning System Telemetry Fixes , 2006 .

[22]  John M. Marzluff,et al.  Comparative accuracy of aerial and ground telemetry locations of foraging raptors , 1994 .

[23]  J. Squires,et al.  Effect of forest canopy on GPS-based movement data , 2005 .

[24]  M. Hebblewhite,et al.  Multiscale wolf predation risk for elk: does migration reduce risk? , 2007, Oecologia.

[25]  Alan H. Strahler,et al.  Validation of the global land cover 2000 map , 2006, IEEE Transactions on Geoscience and Remote Sensing.

[26]  Markus Neteler,et al.  Wildlife tracking data management: a new vision , 2010, Philosophical Transactions of the Royal Society B: Biological Sciences.

[27]  Brian Dennis,et al.  Hierarchical models in ecology: confidence intervals, hypothesis testing, and model selection using data cloning. , 2009, Ecology.

[28]  David C. Bowden,et al.  Evaluation of a Telemetry System for Measuring Habitat Usage in Mountainous Terrain , 1987 .

[29]  Mac Schwager,et al.  Robust classification of animal tracking data , 2007 .

[30]  Christopher O. Kochanny,et al.  Comparing Global Positioning System and Very High Frequency Telemetry Home Ranges of White-Tailed Deer , 2009 .

[31]  R. Courtois,et al.  The use of forest maps for the description of wildlife habitats: limits and recommendations , 2001 .

[32]  Brian Dennis,et al.  Data cloning: easy maximum likelihood estimation for complex ecological models using Bayesian Markov chain Monte Carlo methods. , 2007, Ecology letters.

[33]  J. Wickham,et al.  Thematic accuracy of the 1992 National Land-Cover Data for the western United States , 2004 .

[34]  R. Courtois,et al.  Balancing Number of Locations with Number of Individuals in Telemetry Studies , 2006 .

[35]  Chris J. Johnson,et al.  Sensitivity of species-distribution models to error, bias, and model design: An application to resource selection functions for woodland caribou , 2008 .

[36]  B. W. Moser,et al.  Effects of Telemetry Location Error on Space-Use Estimates Using a Fixed-Kernel Density Estimator , 2007 .

[37]  Malcolm P. North,et al.  Microhabitat analysis using radiotelemetry locations and polytomous logistic regression , 1996 .

[38]  Amy Hurford,et al.  GPS Measurement Error Gives Rise to Spurious 180° Turning Angles and Strong Directional Biases in Animal Movement Data , 2009, PloS one.

[39]  Darcy R. Visscher,et al.  GPS measurement error and resource selection functions in a fragmented landscape , 2006 .

[40]  Carl H. Key,et al.  Satellite telemetry: performance of animal-tracking systems , 1991 .

[41]  Tim Wark,et al.  Using high fix rate GPS data to determine the relationships between fix rate, prediction errors and patch selection , 2008 .

[42]  D. Seip,et al.  Grizzly Bear Behavior and Global Positioning System Collar Fix Rates , 2008 .

[43]  Mikio Sugita,et al.  Effects of habitat feature, antenna position, movement, and fix interval on GPS radio collar performance in Mount Fuji, central Japan , 2007, Ecological Research.

[44]  JOHN FIEBERG,et al.  Utilization Distribution Estimation Using Weighted Kernel Density Estimators , 2007 .

[45]  Hannah W. McKenzie,et al.  Inferring linear feature use in the presence of GPS measurement error , 2009, Environmental and Ecological Statistics.

[46]  Jon S. Horne,et al.  Correcting Home-Range Models for Observation Bias , 2007 .

[47]  D. Haydon,et al.  Multiple movement modes by large herbivores at multiple spatiotemporal scales , 2008, Proceedings of the National Academy of Sciences.

[48]  MARK S. LINDBERG,et al.  Satellite Telemetry in Avian Research and Management: Sample Size Considerations , 2007 .

[49]  Yosef Cohen,et al.  Effects of moose movement and habitat use on GPS collar performance , 1996 .

[50]  R. G. Wright,et al.  Fix Success and Accuracy of Global Positioning System Collars in Old-Growth Temperate Coniferous Forests , 2007 .

[51]  Lars Edenius,et al.  Field test of a GPS location system for moose Alces alces under Scandinavian boreal conditions , 1997, Wildlife Biology.

[52]  Håkan Sand,et al.  Building a mechanistic understanding of predation with GPS-based movement data , 2010, Philosophical Transactions of the Royal Society B: Biological Sciences.

[53]  Gordon B. Stenhouse,et al.  Uncontrolled field performance of Televilt GPS-Simplex™ collars on grizzly bears in western and northern Canada , 2004 .

[54]  Gordon B. Stenhouse,et al.  Removing GPS collar bias in habitat selection studies , 2004 .

[55]  Juan M. Morales,et al.  EXTRACTING MORE OUT OF RELOCATION DATA: BUILDING MOVEMENT MODELS AS MIXTURES OF RANDOM WALKS , 2004 .

[56]  Philip D. McLoughlin,et al.  Overcoming radiotelemetry bias in habitat- selection studies , 1999 .

[57]  John W. Zimmerman,et al.  Radiotelemetry error : location error method compared with error polygons and confidence ellipses , 1995 .

[58]  David Ganskopp,et al.  GPS Error in Studies Addressing Animal Movements and Activities , 2007 .

[59]  Stephen M. Krone,et al.  Analyzing animal movements using Brownian bridges. , 2007, Ecology.

[60]  Donna Delparte,et al.  Effects of radio‐collar position and orientation on GPS radio‐collar performance, and the implications of PDOP in data screening , 2005 .

[61]  Bernie J. McConnell,et al.  Estimating space‐use and habitat preference from wildlife telemetry data , 2008 .

[62]  L. Mike Conner,et al.  A COMPARISON OF DISTANCE-BASED AND CLASSIFICATION-BASED ANALYSES OF HABITAT USE , 2003 .

[63]  Bruce D. Leopold,et al.  Evaluation of a GPS collar for white-tailed deer. , 2000 .

[64]  Charles R. Anderson,et al.  Estimating cougar predation rates from GPS location clusters , 2003 .

[65]  James S. Clark,et al.  POPULATION TIME SERIES: PROCESS VARIABILITY, OBSERVATION ERRORS, MISSING VALUES, LAGS, AND HIDDEN STATES , 2004 .

[66]  Gary C. White,et al.  Analysis of Wildlife Radio-Tracking Data , 1990 .

[67]  BRUNO CARGNELUTTI,et al.  Testing Global Positioning System Performance for Wildlife Monitoring Using Mobile Collars and Known Reference Points , 2007 .

[68]  R. Rempel,et al.  Effects of differential correction on accuracy of a GPS animal location system , 1997 .

[69]  P. Turchin.  Quantitative analysis of movement : measuring and modeling population redistribution in animals and plants , 1998 .

[70]  Kevin P. Kenow,et al.  Evaluating habitat selection with radio-telemetry triangulation error , 1992 .

[71]  Darcy R. Visscher,et al.  Identifying Movement States From Location Data Using Cluster Analysis , 2010 .

[72]  D. Beyer,et al.  Diurnal versus 24-Hour Sampling of Habitat Use , 1994 .

[73]  Bernie J. McConnell,et al.  The effects of interpolation error and location quality on animal track reconstruction , 2009 .

[74]  Dean P. Anderson,et al.  State-space models link elk movement patterns to landscape characteristics in Yellowstone National Park , 2007 .

[75]  Michael C. Hansen,et al.  Accuracy, Precision, and Observation Rates of Global Positioning System Telemetry Collars , 2008 .

[76]  Francesca Cagnacci,et al.  The home-range concept: are traditional estimators still relevant with modern telemetry technology? , 2010, Philosophical Transactions of the Royal Society B: Biological Sciences.

[77]  R. G. Wright,et al.  Integrating SAS and GIS software to improve habitat-use estimates from radiotelemetry data , 2001 .

[78]  Georges Janeau,et al.  ASSESSING REAL DAILY DISTANCE TRAVELED BY UNGULATES USING DIFFERENTIAL GPS LOCATIONS , 2004 .

[79]  Darcy R. Visscher,et al.  GPS MEASUREMENT ERROR INFLUENCES ON MOVEMENT MODEL PARAMETERIZATION , 2005 .

[80]  Corey J A Bradshaw,et al.  Measurement error causes scale-dependent threshold erosion of biological signals in animal movement data. , 2007, Ecological applications : a publication of the Ecological Society of America.

[81]  Gary C. White,et al.  Effects of biotelemetry triangulation error on detecting habitat selection , 1986 .

[82]  Karl J. Friston,et al.  Hierarchical Models , 2003 .

[83]  Robert G. D'Eon,et al.  MULE DEER SEASONAL MOVEMENTS AND MULTISCALE RESOURCE SELECTION USING GLOBAL POSITIONING SYSTEM RADIOTELEMETRY , 2005 .

[84]  Alan A. Ager,et al.  Adjusting for radiotelemetry error to improve estimates of habitat use. , 2002 .

[85]  Chris J. Johnson,et al.  Expectations and realities of GPS animal location collars: results of three years in the field , 2002, Wildlife Biology.

[86]  Darcy R. Visscher,et al.  Scales of movement by elk (Cervus elaphus) in response to heterogeneity in forage resources and predation risk , 2005, Landscape Ecology.

[87]  David B. Marx,et al.  Mitigating spatial differences in observation rate of automated telemetry systems , 1998 .

[88]  M. Hebblewhite,et al.  Distinguishing technology from biology: a critical review of the use of GPS telemetry data in ecology , 2010, Philosophical Transactions of the Royal Society B: Biological Sciences.

[89]  Trent L McDonald,et al.  Estimating habitat selection when GPS fix success is less than 100%. , 2009, Ecology.

[90]  Ian D. Jonsen,et al.  ROBUST STATE-SPACE MODELING OF ANIMAL MOVEMENT DATA , 2005 .

[91]  Christopher O. Kochanny,et al.  GPS radiotelemetry error and bias in mountainous terrain , 2002 .

[92]  Lee A. Vierling,et al.  Effects of habitat on GPS collar performance: using data screening to reduce location error , 2007 .