DOI: 10.5061/dryad.8kprr4xzj
title: Data from: Modelling species distribution at the boundaries of the Earth's climate

description: Correlative species distribution models (SDMs) are widely used to project
 species’ responses to global changes. The climatic niche of a species is
 calibrated under current climate conditions and then projected in space
 and/or time, making model extrapolation an important concern. This issue
 is particularly relevant when considering species that live simultaneously
 at the boundaries of the current Earth’s climate and at the edges of their
 physiological tolerance, such as desert-adapted species. Modelling
 approaches alternatives to SDMs (e.g., hybrid SDMs) have been proposed as
 a better solution to tackle model extrapolation. These models should
 explicitly consider the species’ physiological thermal tolerance,
 producing outputs closer to the species’ ecology. We compared
 correlative SDMs with different extrapolation options (no-extrapolation,
 clamping, fade by clamping, full extrapolation) and hybrid SDMs
 incorporating species-specific thermal tolerances of mammals of the
 Arabian Peninsula. We projected all models under current and
 future climate scenarios and measured the differences between the
 outcomes. We found that different extrapolation options and
 hybrid SDMs produced important differences at least in future projections,
 especially for species physiologically adapted to the extreme climate
 conditions of the desert. Correlative SDMs blocking extrapolation beyond
 the current climate conditions led to more conservative projections, while
 SDMs allowing for extrapolation were extremely more flexible. Hybrid SDMs
 produced intermediate results, with up to 93% of the species losing parts
 of their suitable ranges under future climate scenarios. Our
 findings highlight that correlative SDMs cannot track the true thermal
 tolerances of desert species. Hybrid SDMs hold the premises for a better
 understanding of the impact of global changes on such species, turning on
 a spotlight on a neglected but highly endangered component of
 biodiversity.
description: # Modelling species distribution at the boundaries of the Earth's
 climate ## Description of the data #### File: "R_Code.R"
 **Description:** The R code used to train the correlative Species
 distribution Models (SDMs), to run the data imputation of missing thermal
 tolerances values, and to train the hybrid SDMs. ### File:
 "occurrences.csv" **Description:** A dataframe containing the
 target species occurrences and the relative values of the predictors used
 to train the correlative SDMs. The columns are: **decimalLongitude:** the
 longitude in decimal degrees; **decimalLatitude:** the latitude in decimal
 degrees; **bio2:** the associated value of the mean diurnal temperature
 range, expressed in °C; **bio10:** the associated value of the mean
 temperature of the warmest quarter, expressed in °C; **gst:** the
 associated value of the mean temperature of the growing season, expressed
 in °C; **bio15:** the associated value of the precipitation seasonality,
 expressed in kg m^-2; **npp:** the associated value of the net primary
 productivity, expressed in g C m^−2 yr^−1; **dist_temp:** the associated
 value of the distance from temporary water, expressed in m; **tri:** the
 associated value of the terrain roughness index, expressed in m;
 **urban:** the associated value of the percentage of urban areas;
 **crops:** the associated value of the percentage of croplands;
 **nat_close:** the associated value of the percentage of closed natural
 areas. **File: "background.csv"** **Description:** A dataframe
 containing the background data and the relative values of the predictors
 used to train the correlative SDMs. The columns are the same as in the
 "occurrences.csv" file. #### File: "traits.csv"
 **Description:** A dataframe containing the target species'
 ecological traits used to perform the imputation of missing thermal
 tolerance values. The columns are: * **Weight_g:** The body mass expressed
 in grams (g); * **Habitat:** The habitat-type selected by the species; *
 **Activity_pattern:** The activity pattern of the species; *
 **Litter_size:** The average litter size of the species; *
 **Gestation_length_d:** The average gestation length of the species
 expressed in days; * **Evader:** A variable expressing if the species
 expresses diurnal evasiveness (1) or not (0); * **UCT_c:** The Upper
 Critical Temperature of the species, expressed in °C; * **Diet:** The
 general diet of the species.