Resources for: Spatio-temporal integrated Bayesian species distribution models reveal lack of broad relationships between traits and range shifts

Aim: Climate change and habitat loss or degradation are some of the
greatest threats that species face today, often resulting in range shifts.
Species traits have been discussed as important predictors of range
shifts, with the identification of general trends being of great interest
for conservation efforts. However, studies reviewing relationships between
traits and range shifts have questioned the existence of such generalized
trends, due to mixed results and weak correlations, as well as analytical
shortcomings. The aim of this study was to test this relationship
empirically, using analytical approaches that account for common sources
of bias when assessing range trends.Location: Tanzania, East Africa.Time
period: 1980-1999 and 2000-2020.Major taxa studied: 57 savannah specialist
birds found in Tanzania, belonging to 26 families and 11 orders.Methods:
We applied recently developed integrated spatio-temporal species
distribution models in R-INLA, combining citizen science and bird atlas
data to estimate ranges of species, quantify range shifts, and test the
predictive power of traditional trait groups, as well as exposure-related
and sensitivity traits. We based our study on 40 years of bird
observations in East African savannahs, a biome that has experienced
increasing climatic and non-climatic pressures over recent decades. We
correlated patterns of change with species traits.Results: We find
indications of relationships identified by previous research, but low
average explanatory power of traits from an ecological perspective,
confirming the lack of meaningful general associations. However, our
analysis finds compelling species-specific results.Main conclusions: We
highlight the importance of individual assessments, while demonstrating
the usefulness of our analytical approach for analyses of range shifts.