TY - JOUR A1 - Noonan, Michael J. A1 - Fleming, Christen H. A1 - Tucker, Marlee A. A1 - Kays, Roland A1 - Harrison, Autumn-Lynn A1 - Crofoot, Margaret C. A1 - Abrahms, Briana A1 - Alberts, Susan C. A1 - Ali, Abdullahi H. A1 - Blaum, Niels T1 - Effects of body size on estimation of mammalian area requirements JF - Conservation Biology N2 - Accurately quantifying species' area requirements is a prerequisite for effective area-based conservation. This typically involves collecting tracking data on species of interest and then conducting home-range analyses. Problematically, autocorrelation in tracking data can result in space needs being severely underestimated. Based on the previous work, we hypothesized the magnitude of underestimation varies with body mass, a relationship that could have serious conservation implications. To evaluate this hypothesis for terrestrial mammals, we estimated home-range areas with global positioning system (GPS) locations from 757 individuals across 61 globally distributed mammalian species with body masses ranging from 0.4 to 4000 kg. We then applied block cross-validation to quantify bias in empirical home-range estimates. Area requirements of mammals <10 kg were underestimated by a mean approximately15%, and species weighing approximately100 kg were underestimated by approximately50% on average. Thus, we found area estimation was subject to autocorrelation-induced bias that was worse for large species. Combined with the fact that extinction risk increases as body mass increases, the allometric scaling of bias we observed suggests the most threatened species are also likely to be those with the least accurate home-range estimates. As a correction, we tested whether data thinning or autocorrelation-informed home-range estimation minimized the scaling effect of autocorrelation on area estimates. Data thinning required an approximately93% data loss to achieve statistical independence with 95% confidence and was, therefore, not a viable solution. In contrast, autocorrelation-informed home-range estimation resulted in consistently accurate estimates irrespective of mass. When relating body mass to home range size, we detected that correcting for autocorrelation resulted in a scaling exponent significantly >1, meaning the scaling of the relationship changed substantially at the upper end of the mass spectrum. KW - allometry KW - animal movement KW - area-based conservation KW - autocorrelation KW - home range KW - kernel density estimation KW - reserve design KW - scaling Y1 - 2019 VL - 34 IS - 4 PB - Wiley-Blackwell CY - Oxford ER - TY - GEN A1 - Noonan, Michael J. A1 - Fleming, Christen H. A1 - Tucker, Marlee A. A1 - Kays, Roland A1 - Harrison, Autumn-Lynn A1 - Crofoot, Margaret C. A1 - Abrahms, Briana A1 - Alberts, Susan C. A1 - Ali, Abdullahi H. A1 - Blaum, Niels T1 - Effects of body size on estimation of mammalian area requirements T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Accurately quantifying species' area requirements is a prerequisite for effective area-based conservation. This typically involves collecting tracking data on species of interest and then conducting home-range analyses. Problematically, autocorrelation in tracking data can result in space needs being severely underestimated. Based on the previous work, we hypothesized the magnitude of underestimation varies with body mass, a relationship that could have serious conservation implications. To evaluate this hypothesis for terrestrial mammals, we estimated home-range areas with global positioning system (GPS) locations from 757 individuals across 61 globally distributed mammalian species with body masses ranging from 0.4 to 4000 kg. We then applied block cross-validation to quantify bias in empirical home-range estimates. Area requirements of mammals <10 kg were underestimated by a mean approximately15%, and species weighing approximately100 kg were underestimated by approximately50% on average. Thus, we found area estimation was subject to autocorrelation-induced bias that was worse for large species. Combined with the fact that extinction risk increases as body mass increases, the allometric scaling of bias we observed suggests the most threatened species are also likely to be those with the least accurate home-range estimates. As a correction, we tested whether data thinning or autocorrelation-informed home-range estimation minimized the scaling effect of autocorrelation on area estimates. Data thinning required an approximately93% data loss to achieve statistical independence with 95% confidence and was, therefore, not a viable solution. In contrast, autocorrelation-informed home-range estimation resulted in consistently accurate estimates irrespective of mass. When relating body mass to home range size, we detected that correcting for autocorrelation resulted in a scaling exponent significantly >1, meaning the scaling of the relationship changed substantially at the upper end of the mass spectrum. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1206 KW - allometry KW - animal movement KW - area-based conservation KW - autocorrelation KW - home range KW - kernel density estimation KW - reserve design KW - scaling Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-526824 SN - 1866-8372 IS - 4 ER - TY - JOUR A1 - Noonan, Michael J. A1 - Tucker, Marlee A. A1 - Fleming, Christen H. A1 - Akre, Thomas S. A1 - Alberts, Susan C. A1 - Ali, Abdullahi H. A1 - Altmann, Jeanne A1 - Antunes, Pamela Castro A1 - Belant, Jerrold L. A1 - Beyer, Dean A1 - Blaum, Niels A1 - Boehning-Gaese, Katrin A1 - Cullen Jr, Laury A1 - de Paula, Rogerio Cunha A1 - Dekker, Jasja A1 - Drescher-Lehman, Jonathan A1 - Farwig, Nina A1 - Fichtel, Claudia A1 - Fischer, Christina A1 - Ford, Adam T. A1 - Goheen, Jacob R. A1 - Janssen, Rene A1 - Jeltsch, Florian A1 - Kauffman, Matthew A1 - Kappeler, Peter M. A1 - Koch, Flavia A1 - LaPoint, Scott A1 - Markham, A. Catherine A1 - Medici, Emilia Patricia A1 - Morato, Ronaldo G. A1 - Nathan, Ran A1 - Oliveira-Santos, Luiz Gustavo R. A1 - Olson, Kirk A. A1 - Patterson, Bruce D. A1 - Paviolo, Agustin A1 - Ramalho, Emiliano Estero A1 - Rosner, Sascha A1 - Schabo, Dana G. A1 - Selva, Nuria A1 - Sergiel, Agnieszka A1 - da Silva, Marina Xavier A1 - Spiegel, Orr A1 - Thompson, Peter A1 - Ullmann, Wiebke A1 - Zieba, Filip A1 - Zwijacz-Kozica, Tomasz A1 - Fagan, William F. A1 - Mueller, Thomas A1 - Calabrese, Justin M. T1 - A comprehensive analysis of autocorrelation and bias in home range estimation JF - Ecological monographs : a publication of the Ecological Society of America. N2 - Home range estimation is routine practice in ecological research. While advances in animal tracking technology have increased our capacity to collect data to support home range analysis, these same advances have also resulted in increasingly autocorrelated data. Consequently, the question of which home range estimator to use on modern, highly autocorrelated tracking data remains open. This question is particularly relevant given that most estimators assume independently sampled data. Here, we provide a comprehensive evaluation of the effects of autocorrelation on home range estimation. We base our study on an extensive data set of GPS locations from 369 individuals representing 27 species distributed across five continents. We first assemble a broad array of home range estimators, including Kernel Density Estimation (KDE) with four bandwidth optimizers (Gaussian reference function, autocorrelated‐Gaussian reference function [AKDE], Silverman's rule of thumb, and least squares cross‐validation), Minimum Convex Polygon, and Local Convex Hull methods. Notably, all of these estimators except AKDE assume independent and identically distributed (IID) data. We then employ half‐sample cross‐validation to objectively quantify estimator performance, and the recently introduced effective sample size for home range area estimation ( N̂ area ) to quantify the information content of each data set. We found that AKDE 95% area estimates were larger than conventional IID‐based estimates by a mean factor of 2. The median number of cross‐validated locations included in the hold‐out sets by AKDE 95% (or 50%) estimates was 95.3% (or 50.1%), confirming the larger AKDE ranges were appropriately selective at the specified quantile. Conversely, conventional estimates exhibited negative bias that increased with decreasing N̂ area. To contextualize our empirical results, we performed a detailed simulation study to tease apart how sampling frequency, sampling duration, and the focal animal's movement conspire to affect range estimates. Paralleling our empirical results, the simulation study demonstrated that AKDE was generally more accurate than conventional methods, particularly for small N̂ area. While 72% of the 369 empirical data sets had >1,000 total observations, only 4% had an N̂ area >1,000, where 30% had an N̂ area <30. In this frequently encountered scenario of small N̂ area, AKDE was the only estimator capable of producing an accurate home range estimate on autocorrelated data. KW - animal movement KW - kernel density estimation KW - local convex hull KW - minimum convex polygon KW - range distribution KW - space use KW - telemetry KW - tracking data Y1 - 2018 U6 - https://doi.org/10.1002/ecm.1344 SN - 0012-9615 SN - 1557-7015 VL - 89 IS - 2 PB - Wiley CY - Hoboken ER -