Modeling spatiotemporal abundance of mobile wildlife in highly variable environments using boosted GAMLSS hurdle models

Journal Article

Title: Modeling spatiotemporal abundance of mobile wildlife in highly variable environments using boosted GAMLSS hurdle models

Author:

Smith, A.; Hofner, B.; Lamb, J.; Osenkowski, J.; Allison, T.; Sadoti, G.; McWilliams, S.; Paton, P.

Publication Date:

March 1, 2019

Journal:

Ecology and Evolution

Volume:

Issue:

Pages:

2346-2364

Publisher:

Wiley

Affiliation

University of Rhode Island, Friedrich–Alexander University Erlangen–Nürnberg, Rhode Island Department of Environmental Management, American Wind Wildlife Institute (AWWI), University of Nevada

Technology:

Wind Energy, Fixed Offshore Wind

Receptor:

Seabirds, Birds

Document Access

Website:

External Link

Attachment:

Access File
Notice: This material may be protected by Copyright Law.

Citation

Smith, A.; Hofner, B.; Lamb, J.; Osenkowski, J.; Allison, T.; Sadoti, G.; McWilliams, S.; Paton, P. (2019). Modeling spatiotemporal abundance of mobile wildlife in highly variable environments using boosted GAMLSS hurdle models. Ecology and Evolution, 9(5), 2346-2364. https://doi.org/10.1002/ece3.4738

Download Citation File

Abstract

Modeling organism distributions from survey data involves numerous statistical challenges, including accounting for zero‐inflation, overdispersion, and selection and incorporation of environmental covariates. In environments with high spatial and temporal variability, addressing these challenges often requires numerous assumptions regarding organism distributions and their relationships to biophysical features. These assumptions may limit the resolution or accuracy of predictions resulting from survey‐based distribution models. We propose an iterative modeling approach that incorporates a negative binomial hurdle, followed by modeling of the relationship of organism distribution and abundance to environmental covariates using generalized additive models (GAM) and generalized additive models for location, scale, and shape (GAMLSS). Our approach accounts for key features of survey data by separating binary (presence‐absence) from count (abundance) data, separately modeling the mean and dispersion of count data, and incorporating selection of appropriate covariates and response functions from a suite of potential covariates while avoiding overfitting. We apply our modeling approach to surveys of sea duck abundance and distribution in Nantucket Sound (Massachusetts, USA), which has been proposed as a location for offshore wind energy development. Our model results highlight the importance of spatiotemporal variation in this system, as well as identifying key habitat features including distance to shore, sediment grain size, and seafloor topographic variation. Our work provides a powerful, flexible, and highly repeatable modeling framework with minimal assumptions that can be broadly applied to the modeling of survey data with high spatiotemporal variability. Applying GAMLSS models to the count portion of survey data allows us to incorporate potential overdispersion, which can dramatically affect model results in highly dynamic systems. Our approach is particularly relevant to systems in which little a priori knowledge is available regarding relationships between organism distributions and biophysical features, since it incorporates simultaneous selection of covariates and their functional relationships with organism responses.