The need for standardization in wildlife science: home range estimators as an example

Abstract

Individual studies in wildlife science are indicative rather than conclusive. Although multiple studies can be meta-analyzed in such a way that scientific hypotheses can be tested, robust meta-analyses are often difficult or impossible if variables of interest are not measured in a uniform manner. We hypothesized that measurements, even of basic and unequivocal variables, are rarely standardized in wildlife sciences. We tested this assumption by reviewing randomly selected papers that describe the home range of mammals (n=25) and birds (n=25). In these papers, home ranges were calculated using 11 methods and 8 computer programs. The number of radiolocations used to calculate home ranges varied from 9 to >2,000. By estimating home ranges for two radiotelemetry data sets, we demonstrate that home ranges are not comparable if different methods are used and that estimates of home range are not standardized. We assume that measurements of other biological variables are even less consistent across studies. In order to advance wildlife sciences, we believe that standardization initiatives are required at an international level.

Howler Monkeys

“…discussed above, we tested whether home range size is affected by (1a) fragment size, (1b) population density, (1c) group size, and (1d) group biomass, and whether day range length is affected by (2a) fragment size, (2b) population density, (2c) group size, and the contribution of (2d) fruits and (2e) leaves to the diet. We also included species and method of estimating home range as factors, due to evidence showing that home range size differs among howler species and that estimates may vary widely among methods (Grueter et al 2009 ;Gula and Theuerkauf 2013 ) as discussed below.…”

Ranging Behavior and Spatial Cognition of Howler Monkeys

“…discussed above, we tested whether home range size is affected by (1a) fragment size, (1b) population density, (1c) group size, and (1d) group biomass, and whether day range length is affected by (2a) fragment size, (2b) population density, (2c) group size, and the contribution of (2d) fruits and (2e) leaves to the diet. We also included species and method of estimating home range as factors, due to evidence showing that home range size differs among howler species (Bicca-Marques 2003 ) and that estimates may vary widely among methods (Grueter et al 2009 ;Gula and Theuerkauf 2013 ) as discussed below.…”

Spatial ecology of invasive feral cats on San Clemente Island: implications for control and management

“…We calculated 95% and 50% KDEs by removing the outermost 5% and 50% of locations, respectively. We also calculated 100% MCP home ranges because they are simple to calculate and are historically popular, and thus provide a standardized metric for coarse interstudy comparison (Gula and Theuerkauf 2013). However, they are not considered robust quantitative estimators, and are subject to multiple biases (Laver and Kelly 2008).…”