title: A framework for analyzing the robustness of movement models to variable step discretization.
abstract: When sampling animal movement paths, the frequency at which location measurements are attempted is a critical feature for data analysis. Important quantities derived from raw data, e.g. travel distance or sinuosity, can differ largely based on the temporal resolution of the data. Likewise, when movement models are fitted to data, parameter estimates have been demonstrated to vary with sampling rate. Thus, biological statements derived from such analyses can only be made with respect to the resolution of the underlying data, limiting extrapolation of results and comparison between studies. To address this problem, we investigate whether there are models that are robust against changes in temporal resolution. First, we propose a mathematically rigorous framework, in which we formally define robustness as a model property. We then use the framework for a thorough assessment of a range of basic random walk models, in which we also show how robustness relates to other probabilistic concepts. While we found robustness to be a strong condition met by few models only, we suggest a new method to extend models so as to make them robust. Our framework provides a new systematic, mathematically founded approach to the question if, and how, sampling rate of movement paths affects statistical inference.
authors: Department of Mathematical and Statistical Sciences, CAB 632, University of Alberta, Edmonton, AB, T6G 2G1, Canada. ulrike.schlaegel@gmail.com.|Plant Ecology and Conservation Biology, University of Potsdam, Am Mühlenberg 3, 14476, Potsdam, Germany. ulrike.schlaegel@gmail.com.
authors: Ulrike E
authors: UE
authors: Schlägel
authors: Department of Mathematical and Statistical Sciences, CAB 632, University of Alberta, Edmonton, AB, T6G 2G1, Canada.|Department of Biological Sciences, CW 405, Biological Sciences Bldg., University of Alberta, Edmonton, AB, T6G 2E9, Canada.
authors: Mark A
authors: MA
authors: Lewis
mesh_terms: D000818:Animals; D008954:Models, Biological; D009043:Motor Activity / Q000502:physiology*; D015203:Reproducibility of Results
keywords: Animal movement; Discretization; GPS data; Parameter estimation; Random walk; Sampling rate