Mitigating spatial differences in observation rate of automated telemetry systems

Bruce K. Johnson, Alan A. Ager, Scott L. Findholt, Michael J. Wisdom, David B. Marx, John W. Kern, Larry D. Bryant

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

Wildlife ecologists are increasingly interested in determining spatial distributions and habitat use of ungulates from locations estimated from both conventional and automated telemetry systems (ATS). If the performance of an ATS causes spatial versus random variation in probability of obtaining an acceptable location (observation rate), analysis of habitat selection is potentially biased. We define observation rate as the percentage of acceptable locations (i.e., those that meet signal strength, signal-to-noise ratios, geometric dilution of precision criteria) of the total locations attempted. An ATS at the Starkey Experimental Forest and Range (Starkey) in Oregon tracks movements of elk (Cervus elaphus), mule deer (Odocoileus hemionus)., and cattle. We detected localized variation in observation rate of stationary radiocollars in 1993. Subsequently, we devised a method to estimate observation rate at various spatial scales using animal location data over 4 years (199295; n = 907,156 location attempts) to determine if the variation was spatial or random. We formulated 5 variants of a general linear model to obtain estimates of spatial variation in observation rate. All 5 models assumed spatially correlated error terms estimated from isotropic semivariograms. Three models included environmental variables as covariates correlated with observation rate. Models then were compared based on mean error, coefficient of determination, and residual plots. Random variation accounted for 47-53%, and spatial variation accounted for 38-45% of the variation in observation rate. One model was selected to demonstrate application of the correction to mitigate spatial bias in observation rate. Our results demonstrate the utility of semivariograms to detect and quantify spatial variation in observation rate of animal locations determined from an ATS.

Original languageEnglish (US)
Pages (from-to)958-967
Number of pages10
JournalJournal of Wildlife Management
Volume62
Issue number3
DOIs
StatePublished - Jul 1998

Fingerprint

telemetry
spatial variation
Odocoileus hemionus
radio frequency identification
experimental forests
elks
Cervus elaphus
ungulates
habitat preferences
ecologists
wildlife
animals
linear models
spatial distribution
environmental factors
rate
cattle
animal
habitats
ungulate

Keywords

  • Automated telemetry systems
  • GPS
  • Habitat selection
  • LORAN-C
  • Observation rate
  • REML
  • Radiotelemetry
  • Sampling bias
  • Semivariogram
  • Spatial statistics

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology
  • Nature and Landscape Conservation

Cite this

Johnson, B. K., Ager, A. A., Findholt, S. L., Wisdom, M. J., Marx, D. B., Kern, J. W., & Bryant, L. D. (1998). Mitigating spatial differences in observation rate of automated telemetry systems. Journal of Wildlife Management, 62(3), 958-967. https://doi.org/10.2307/3802548

Mitigating spatial differences in observation rate of automated telemetry systems. / Johnson, Bruce K.; Ager, Alan A.; Findholt, Scott L.; Wisdom, Michael J.; Marx, David B.; Kern, John W.; Bryant, Larry D.

In: Journal of Wildlife Management, Vol. 62, No. 3, 07.1998, p. 958-967.

Research output: Contribution to journalArticle

Johnson, BK, Ager, AA, Findholt, SL, Wisdom, MJ, Marx, DB, Kern, JW & Bryant, LD 1998, 'Mitigating spatial differences in observation rate of automated telemetry systems', Journal of Wildlife Management, vol. 62, no. 3, pp. 958-967. https://doi.org/10.2307/3802548
Johnson BK, Ager AA, Findholt SL, Wisdom MJ, Marx DB, Kern JW et al. Mitigating spatial differences in observation rate of automated telemetry systems. Journal of Wildlife Management. 1998 Jul;62(3):958-967. https://doi.org/10.2307/3802548
Johnson, Bruce K. ; Ager, Alan A. ; Findholt, Scott L. ; Wisdom, Michael J. ; Marx, David B. ; Kern, John W. ; Bryant, Larry D. / Mitigating spatial differences in observation rate of automated telemetry systems. In: Journal of Wildlife Management. 1998 ; Vol. 62, No. 3. pp. 958-967.
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