Predicting the breeding distribution of wader species across climatic and environmental gradients

Developing and applying species distribution models is particularly urgent for species currently facing high levels of environmental change. Waders (Charadrii) are among the most species rich groups of birds breeding at higher latitudes and the one where species are declining fastest. Iceland holds a large part of the global population of several wader species breeding sympatrically across unusual climate and environmental gradients. This provides an opportunity to assess synergy in habitat selection and occurrence of species usually occupying wide latitudinal ranges from temperate to arctic. In addition, the Icelandic wader habitats are facing significant and increasing pressures from anthropogenic sources putting in risk these populations. We built distribution models for several waders with the aim of identifying synergies in occurrence which allows better prioritisation of conservation efforts., Species occurrence data in the lowland areas (<200m a.s.l.) of Iceland were derived from georeferenced point count data (standardized 5 min. point counts with a 200m radius) carried out during  during the breeding season (May and June) from 2007 to 2019. Species occurrence data in the highland areas (>200m a.s.l.) were derived from georeferenced transect counts carried out during June and July from 1999 to 2004. For each transect, we used the species counted in the midpoint of the transect and excluded counts recorded with distance to the focal bird >200 m or counts recorded with no distance. All counts were transformed to presence data, so the species occurrence dataset consists of a set of longitude and latitude coordinates.
Species distribution models (SDMs) were generated using Bayesian Additive Regression Trees (BART) following the methodology/code described in Carlson (2020). BART models were run with the default parameters as implemented in dbarts in the R pack..., , # Predicting the breeding distribution of wader species across climatic and environmental gradients

[https://doi.org/10.5061/dryad.bzkh189m9](https://doi.org/10.5061/dryad.bzkh189m9)

## Description of the data and file structure

This repository archives the data and code associated with the manuscript titled: \"Predicting the breeding distribution of wader species across climatic- and environmental gradients\". The materials are organised into species data, containing the occurrence of nine Icelandic breeding waders derived from georeferenced point and transect counts collected across Iceland, all environmental raster layers resampled to a pixel resolution of ca. 400 x 400 meters width and a spatial reference of WGS84, and the R script used to generate the species distribution models presented in the manuscript. 

Below is a breakdown of the file contents.

### Files and variables

#### File: occurrence_generalised.xlsx

**Description:** This Excel file contains the occurrence data of...,