An iconic messenger of climate change? Predicting the range dynamics of the European Bee-eater (Merops apiaster)

Abstract

When environmental conditions change, species usually face three options: adaptation, range shifts, or extinction. In the wake of climate change, it is generally believed that range shifts are the norm in mobile species such as birds, resulting in poleward range shifts. The European Bee-eater is a predominantly Mediterranean species which has expanded its range to higher latitudes over the last decades. Germany in particular has seen a surge in breeding pairs and foundation of new colonies. However, while many experts suggest climate warming as the main driver behind this range expansion, an explicit quantification remains open. Here, we use an ensemble modelling approach to study the recent climatic niche suitability of the European Bee-eater across Europe with a special focus on Germany and project its predicted Palaearctic breeding distribution onto the year 2050 using two global circulation models and two representative concentration pathways. Models were able to predict the current European range of the species with some underestimated areas in Central and Eastern Europe, depending on the selected model. We found a strong relationship between climatic suitable areas and estimated population sizes across European countries that is reflected in most algorithms. In particular, the German population size is in line with climate suitability in the country suggesting a strong climate–population relationship and a high degree of niche filling. Most future predictions point to an ongoing northward expansion of the species while areas in Southern Europe and the Maghreb area remain largely suitable. The strong climate–population relationship makes the European Bee-eater an appropriate indicator species for climate change. Yet the high variability of modelling algorithms also call for caution of using these techniques without careful inspection.

Species Traits Drive Long-Term Population Trends of Common Breeding Birds in Northern Italy

“…However, 13 of the 31 farmland species showed significant positive trends, highlighting that species-specific drivers can occur and determine different demographic responses. For instance, some thermophilic farmland species, such as the European Bee-eater, showed strong positive trends, probably favored by temperature increasing [ 167 , 168 , 169 ]. Woodland birds, which appear stable or increasing in Europe [ 22 , 43 , 170 ], confirmed this pattern in our study area.…”

Projected dynamics of breeding habitat suitability for a steppe-land bird warrant anticipatory conservation actions

“…Habitat suitability has been linked to population size and trends in birds (Green et al, 2008;Stiels et al, 2021). We showed that large areas of the study region are predicted as suitable in the future, and that a stable mean habitat suitability is likely.…”

“…However, the two RCPs employed in our study can provide valuable insights on the effect of global change on habitat suitability, as demonstrated by their extensive use (e.g. Kiss et al, 2020;Stiels et al, 2021). We also limited our study to the breeding period:…”

“…To establish effective conservation practices, state-of-the-art habitat suitability scenarios for the focal species are required (Miller-Rushing, Primack, & Sekercioglu, 2010;Mcshea, 2014), and rigorous analyses of suitability dynamics are essential to reveal the sensitivity of species to global change and to guide conservation efforts (Stiels et al, 2021). Moreover, recent studies are increasingly evidencing the importance of distinguishing between the effects of long-term vs. short-term environmental change (Reside et al, 2010;Milanesi, Della Rocca, & Robinson, 2020).…”

An introduction to predictive distribution modelling for conservation to encourage novel perspectives

“…That is, low abundances (and hence lower genetic diversity) could reduce local rates of adaptation at range edges, with gene flow from the abundant range center swamping any effect of local adaptation at the range edge that would facilitate range expansion when conditions change (Haldane, 1956; but see Kottler et al, 2021). Studies on invasive species have the potential to improve our understanding of the mechanisms that promote expansion from original range boundaries (e.g., the tolerance niche of the Asian Openbill Bird - Lei & Liu, 2021; and climate matching in the European Bee-eater - Stiels et al, 2021).…”