Distribution models for riparian landbirds and waterbirds in the Sacramento-San Joaquin Delta

SUMMARY Distribution models for 9 riparian landbird species and 6 groups of waterbird species in the Sacramento-San Joaquin River Delta of California. DESCRIPTION These predictive models were developed to relate the probability of species or group presence as a function of the surrounding landscape, facilitating predictions of species presence or absence over the entire landscape. Each .RData object is structured as a list containing individual model objects of class `gbm` for each species or group. Models were developed using Boosted Regression Trees, implemented in R using the R packages `dismo` (Hijmans et al. 2021) and `gbm` (Greenwell et al. 2020). Models were developed from pre-existing bird survey data, including 2,547 surveys for riparian landbirds conducted at 716 unique locations throughout the Central Valley of California during the breeding season (May and June), 2011–2019, and 7,820 surveys for waterbirds conducted at 504 unique locations in the Delta during the fall (July 15–November 15) and winter (November 17–March 5) seasons, 2013–14 and 2014–15. Waterbird models were developed for each of the fall and winter seasons, with 46 species grouped into 6 distinct groups defined by similar habitat requirements, foraging style, and diet. These models were used to predict the distribution of each species and group across a baseline Delta landscape (representing land cover in 2018), and these predictions were used to identify Priority Bird Conservation Areas in the Delta. In addition, the models were used to predict distributions for alternative scenarios of future landscape change, and to evaluate the net change from the baseline distributions in the total area of suitable habitat. These models are required for evaluating the change in Biodiversity Support benefits using the R package "DeltaMultipleBenefits", which provides the code and work flow for repeating the initial scenario analyses or analyzing new scenarios. For additional details about the development and applications of these data, please see: Dybala K, Sesser K, Reiter M, Shuford WD, Golet GH, Hickey C, Gardali T. (In review) Priority Bird Conservation Areas in California’s Sacramento–San Joaquin Delta. Dybala KE, et al. (In review) Multiple-benefit Conservation in Practice: A Framework for Quantifying Multi-dimensional Impacts of Landscape Change in California’s Sacramento–San Joaquin Delta. Dybala KE (2023) DeltaMultipleBenefits: Projecting the Multiple Benefits of Land Cover Change i