Estimating Regions of Oceanographic Importance for Seabirds Using A-Spatial Data
Humphries, Grant Richard Woodrow
Advances in GPS tracking technologies have allowed for rapid assessment of important oceanographic regions for seabirds. This allows us to understand seabird distributions, and the characteristics which determine the success of populations. In many cases, quality GPS tracking data may not be available; however, long term population monitoring data may exist. In this study, a method to infer important oceanographic regions for seabirds will be presented using breeding sooty shearwaters as a case study. This method combines a popular machine learning algorithm (generalized boosted regression modeling), geographic information systems, long-term ecological data and open access oceanographic datasets. Time series of chick size and harvest index data derived from a long term dataset of Maori ‘muttonbirder’ diaries were obtained and used as response variables in a gridded spatial model. It was found that areas of the sub-Antarctic water region best capture the variation in the chick size data. Oceanographic features including wind speed and charnock (a derived variable representing ocean surface roughness) came out as top predictor variables in these models. Previously collected GPS data demonstrates that these regions are used as “flyways” by sooty shearwaters during the breeding season. It is therefore likely that wind speeds in these flyways affect the ability of sooty shearwaters to provision for their chicks due to changes in flight dynamics. This approach was designed to utilize machine learning methodology but can also be implemented with other statistical algorithms. Furthermore, these methods can be applied to any long term time series of population data to identify important regions for a species of interest.
Publisher: PLOS One
Rights Statement: Copyright: © 2015 Grant Richard Woodrow Humphries. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: The raw data used to create the harvest indices, and chick size index used in this manuscript are available upon request with legal restrictions. Interested researchers may submit requests to the author ( firstname.lastname@example.org) or Prof. Henrik Moller ( email@example.com). A reduced version of the three mean harvest indices which does not include identifying information can be downloaded at: http://www.humphriesresearch.com/ work.html. The indices were published in Humphries et al. , in Ecological Applications. The ECMWF data used for modeling are already available open access on the web at www.ECMWF.int. Third-party GLS tracking data are available upon request from Dr. Scott Shaffer ( firstname.lastname@example.org), or Dr. David Thompson ( David.Thompson@niwa.co.nz).
Keywords: A-Spatial Data, seabird tracking, sooty shearwater
Research Type: Journal Article
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