Unravelling the complexities of temporal biotic homogenisation and heterogenization: Avian assemblage dynamics in Britain

Biotic homogenization is a process whereby species assemblages become more similar through time.  The standard way of identifying the process of biotic homogenization is to look for decreases in spatial beta-diversity. However, using a single assemblage-level metric to assess homogenization can mask important changes in the occupancy patterns of individual species. Here, we analysed changes in the spatial beta-diversity patterns (i.e., biotic heterogenization or homogenization) of British bird assemblages within 30km x 30km regions between two periods (1988-1991 and 2008-2011). We partitioned the change in spatial beta-diversity into extirpation and colonisation resultant change (i.e., change in spatial beta-diversity within each region resulting from both extirpation and colonisation). We used measures of abiotic change in combination with Bayesian modelling to disentangle the drivers of biotic heterogenization and homogenization. We detected both heterogenization and homogenization ac..., , , # Data and code from: Unravelling the complexities of temporal biotic homogenisation and heterogenization: avian assemblage dynamics in Britain

[https://doi.org/10.5061/dryad.hx3ffbgm6](https://doi.org/10.5061/dryad.hx3ffbgm6)

## Description of the data and file structure

Data is contained within the \"Datafiles\" folder. This data consists of:

* Bird_list.csv: List of birds present in the study area during the study periods
* Centroids_10.csv: Centroids (latitude and longitude) of the centers of each hectad (10 km x 10 km grid).
* ClimChaprec_30.csv: Change in precipitation between the two study periods
* ClimChatavg_30.csv: Change in average temperature between the two study periods
* consensus_jetz_3000: Jetz consensus trees (see Jetz et al. 2012 for more information)
* data_30km.csv: the full dataset (if only the data is needed without running the script to obtain metrics and combine into one datafile)
* elev_30km: Elevation data for Britain in 30 km x 30vkm grids
* ...