Does perspective matter? A case study comparing Eulerian and Lagrangian estimates of common murre (Uria aalge) distributions

Abstract

Studies estimating species' distributions require information about animal locations in space and time. Location data can be collected using surveys within a predetermined frame of reference (i.e., Eulerian sampling) or from animal‐borne tracking devices (i.e., Lagrangian sampling). Integration of observations obtained from Eulerian and Lagrangian perspectives can provide insights into animal movement and habitat use. However, contemporaneous data from both perspectives are rarely available, making examination of biases associated with each sampling approach difficult. We compared distributions of a mobile seabird observed concurrently from ship, aerial, and satellite tag surveys during May, June, and July 2012 in the northern California Current. We calculated utilization distributions to quantify and compare variability in common murre ( Uria aalge ) space use and examine how sampling perspective and platform influence observed patterns. Spatial distributions of murres were similar in May, regardless of sampling perspective. Greatest densities occurred in coastal waters off southern Washington and northern Oregon, near large murre colonies and the mouth of the Columbia River. Density distributions of murres estimated from ship and aerial surveys in June and July were similar to those observed in May, whereas distributions of satellite‐tagged murres in June and July indicated northward movement into British Columbia, Canada, resulting in different patterns observed from Eulerian and Lagrangian perspectives. These results suggest that the population of murres observed in the northern California Current during spring and summer includes relatively stationary individuals attending breeding colonies and nonstationary, vagile adults and subadults. Given the expected growth of telemetry studies and advances in survey technology (e.g., unmanned aerial systems), these results highlight the importance of considering methodological approaches, spatial extent, and synopticity of distribution data sets prior to integrating data from different sampling perspectives.

Individual repeatability of avian migration phenology: A systematic review and meta‐analysis

“…Lagrangian tracking of individuals through time and space (i.e. animal-borne tracking devices) may therefore be more suited to studies of the timing of individual movements (Phillips et al, 2019). For example, the accuracy of estimates of timing of arrival at the breeding grounds as observed through conventional studies may be low in comparison to more recent methods, such as satellite telemetry, GPS and GLS (Korner-Nievergelt et al, 2012).…”

Density-dependent habitat selection alters drivers of population distribution in northern Yellowstone elk

“…Individual behavior scales up to population-level distributions (Mueller & Fagan 2008), so results from the two perspectives can, in principle, be reconciled. In practice, few studies have compared the Eulerian and Lagrangian approaches to studying population-level space use (but see Phillips et al 2019;Bassing et al 2022). In our case, we find both similarities and discrepancies between our work (Eulerian) and previous studies (Lagrangian) of elk habitat selection in northern Yellowstone (Appendix S7).…”

Assessing the effects of tidal stream marine renewable energy on seabirds: A conceptual framework

“…age, sex, specialization) (Daunt et al, 2007;Camphuysen et al, 2015;Ceia and Ramos, 2015). The ongoing development of habitat models that integrate data from multiple survey types (Louzao et al 2009;Yamamoto et al 2015;Watanuki et al 2016) should encourage combining methods where possible for information on seabird habitat use at individual and population levels over multiple scales (Waggitt et al 2016b;Lieber et al 2019;Phillips et al 2019).…”