DOI: 10.5061/dryad.9kd51c5mp
title: Data and scripts from: Replacement drives native β-diversity of British avifauna, while richness differences shape alien β-diversity

description: Aim: We explored the range shifts of alien and native birds, the responses
 of alien and native β-diversity to abiotic factors, and the effect of
 native diversity on alien β-diversity in two time periods. Location: Great
 Britain. Time period: 1968–1972, 2007–2011. Taxa studied: Breeding birds.
 Methods: We estimated range shifts of alien and native species between the
 periods 1968–1972 and 2007–2011. Following, β-diversity of alien and
 native communities was estimated by Jaccard pairwise index (βtot) and
 partitioned into richness difference and replacement component for each
 period. We built abiotic Generalized Dissimilarity Models including
 abiotic factors for alien and native βtot and their components and a
 biotic model for aliens including native taxonomic and functional
 diversity as predictors. Results: Most alien and half native species
 expanded into new regions during the 40-year period. The native species
 range shifts did not exhibit a clear pattern along the longitudinal or
 latitudinal gradient, while alien species tended to move north-westwards.
 The richness difference was the dominant component of alien β-diversity,
 and the replacement component contributed mostly to native β-diversity.
 Alien β-diversity responded similarly, but less strongly than native
 β-diversity, to the abiotic gradients. Temperature-related variables,
 distance, and precipitation were the most important abiotic drivers of
 native and alien β-diversity. The biotic model of alien β-diversity
 explained more deviance than the abiotic model. Main conclusions: Alien
 species expanded into new regions over the 40 years, with alien
 β-diversity driven mostly by species gains. The effect of environmental
 filtering on alien communities was weaker compared to native communities
 but was slightly reinforced in the second period compared to the first
 period, highlighting the role of environmental change in shaping diversity
 patterns. Native diversity played a key role in driving alien β-diversity,
 through biotic interactions or/and by reflecting climatic suitability or
 niche availability for aliens.
description: We explored the range shifts of
 alien and native breeding bird species of mainland Great Britain between
 the periods 1968–1972 and 2007–2011. We estimated β-diversity and its components (richness
 difference and replacement component) of alien and native communities per
 time period and explored the effect of abiotic factors (climate, land
 cover, human population, and elevation) on alien and native
 β-diversity and their components and of native
 diversity (species richness and functional diversity) on alien
 β-diversity by Generalized Dissimilarity Modelling. Breeding bird
 distribution data of Great Britain for the time periods 1968–1972 and
 2007–2011 (data collected in hectads of 100 km<sup>2</sup>)
 were retrieved from <em>The atlas of breeding birds in Britain and
 Ireland </em>(Sharrock, 1976), <em>Bird Atlas 2007–2011: the
 breeding and wintering birds of Britain and Ireland</em> (Balmer et
 al., 2013), and <em>Breeding and wintering bird distributions in
 Britain and Ireland from citizen science bird atlas</em> (Gillings
 et al., 2019). Filtering of the species was applied based on their status
 that was retrieved from
 the British Trust for Ornithology's BirdFacts database (Robinson,
 2005; https://www.bto.org/understanding-birds/birdfacts), Mcinerny et al. (2022), and Wayman et al. (2022). The trait dataset (body mass, clutch size, foraging location, habitat, activity time, and main diet) of breeding birds was retrieved from Tsianou et al. (2021). Specifically, the traits were compiled from datasets (Storchová et al., 2018) and electronic databases [Handbook of the Birds of the World Alive (https://www.hbw.com)]. Climatic factors (mean temperature, mean temperature range, mean temperature of the warmest month, mean temperature of the coldest month, and mean precipitation), percentage of different land cover types (forest, cropland, grassland, other, and, water), human population and elevation per hectad were calculated with using QGIS 3.18 using data available online. The detailed sources of abiotic factors are provided in the attached Readme.txt and the original paper, while the calculated variables are provided in attached .csv files (climaticA.csv, climaticC, HILDAA.csv, HILDAC.csv, human.popA.csv, human.popC.csv, elevation.csv). All analyses were performed using R version 4.1.0 (R Development Core Team 2021) and required packages are provided in the attached 1_Prepare environmental and diversity data.txt. Additional functions are provided in Nstar function.txt and Windrose function.txt. Species list (along with name changes), trait dataset, and hectads of mainland Great Britain are provided in the Species list.csv (name changes.csv), Traits.csv, and Mainland_GB.csv, respectively.  Scripts for performing analyses are provided in the 2_Estimate range shifts metrics.txt and 3_Run GDMs.txt. Instructions for performing analyses are provided in the Readme.txt. References Balmer, D. E., Gillings, S., Caffrey, B., Swann, R., Downie, I., & Fuller, R. (2013). <em>Bird Atlas 2007-11: the breeding and wintering birds of Britain and Ireland</em>: BTO Thetford. Gillings, S., Balmer, D. E., Caffrey, B. J., Downie, I. S., Gibbons, D. W., Lack, P. C., ... & Fuller, R. J. (2019). Breeding and wintering bird distributions in Britain and Ireland from citizen science bird atlases. <em>Global Ecology and Biogeography</em>, <strong>28</strong>(7), 866-874. https://doi.org/10.1111/geb.12906 McInerny, C. J., Musgrove, A. J., Stoddart, A., Harrop, A. H., & Dudley, S. P. (2022). The British List: a checklist of birds of Britain (10th edition). <em>Ibis</em>, <strong>164</strong>, 860–910. https://doi.org/10.1111/ibi.13065 Robinson, R.A. (2005). <em>BirdFacts: profiles of birds occurring in Britain & Ireland. BTO Research Report</em>, 407, p.Thetford. (http://www.bto.org/birdfacts) Sharrock, J. T. R. (1976). <em>The atlas of breeding birds in Britain and Ireland</em>: A&C Black. Storchová, L., & Hořák, D. (2018). Life‐history characteristics of European birds. <em>Global Ecology and Biogeography,</em> <strong>27</strong>(4), 400-406. https://doi.org/10.1111/geb.12709 Tsianou, M. A., Touloumis, K., & Kallimanis, A. S. (2021). Low spatial congruence between temporal functional β‐diversity and temporal taxonomic and phylogenetic β‐diversity in British avifauna. <em>Ecological Research</em>, <strong>36</strong>(3), 491-505. https://doi.org/10.1111/1440-1703.12209 Wayman, J. P., Sadler, J. P., Pugh, T. A., Martin, T. E., Tobias, J. A., & Matthews, T. J. (2022). Assessing taxonomic and functional change in British breeding bird assemblages over time. <em>Global Ecology and Biogeography</em>, <strong>31</strong>(5), 925-939. https://doi.org/10.1111/geb.13468
description: All data files can be opened and analyses can be performed using
 R software.