Genetic assessment and climate modelling of the Iberian specialist butterfly Euchloe bazae (Lepidoptera: Pieridae)

Abstract

1. Although both positive (expansion of thermophilous species) and negative effects (retraction of cold-adapted species) have been attributed to global warming, range shifts may be constrained by the ecological traits of species.2. This can be especially true for highly specialised organisms like the Spanish Greenish Black-tip (Euchloe bazae), an Iberian endemic specialist of semiarid steppes with a debated taxonomic and conservation status.3. Here, we first seek to clarify the taxonomic status of this butterfly and its populations by using multilocus phylogenetic inference. Then, we update its distribution range and employ ecological niche modelling, combined with other sources of data, to re-evaluate its conservation status. 4. Our results confirm E. bazae as a well-differentiated species with one of the most restricted distribution ranges among the European butterflies.5. We demonstrate that its two disjunct populations, regarded as subspecies, are genetically differentiated and should be treated as independent management units. 6. Climate models under two future emission scenarios suggest an increase of the area climatically suitable. However, the suitability of the areas currently occupied is estimated to decrease, meaning that rapid range shifts could be required for the survival of the species. 7. Given the presumably low dispersal capabilities of E. bazae, its current restricted distribution, high degree of population fragmentation (divided in two distant populations), low intrapopulation genetic variability, decline in extension and abundance, low densities, high yearly fluctuations, and numerous threats to its habitat, we consider that their populations are extremely fragile and we propose to consider it 'Endangered' [EN B1ab(i,ii,iii,iv); B2ab(i,ii,iii,iv)]. Resum (Catalan)1. Tot i que s'han atribuït tant efectes positius (expansi o d'espècies termòfiles) com negatius (contracci o d'espècies adaptades al fred) a l'escalfament global, canvis en les distribucions poden estar condicionats pels trets ecològics de les espècies.

Living on the edge—Genomic and ecological delineation of cryptic lineages in the high‐elevation specialist Erebia nivalis

“…Consequently, given their likely different biogeographic histories, phylogenetic distinctiveness and ecological differentiation, Swiss and Austrian E. nivalis should be recognised as distinct ESU from a management perspective (Casacci et al, 2014; Funk et al, 2012). While there is some debate about the criteria that define an ESU, that is, a conservation unit below the taxonomic level of a species (Fraser & Bernatchez, 2001), the Swiss and Austrian populations of E. nivalis fit the concept well, and similar arguments for the establishment of ESUs in butterflies have been made (e.g., Escuer et al, 2022).…”

Incorporating genomics into insect conservation: Butterflies as a model group

“…Genomics is expected to significantly improve conservation practices by enhancing the discovery of species diversity and the re‐assessment of taxonomic conventions. For example, legal protection of threatened species or populations has been granted after taking note of characterizations of evolutionarily significant units using genetics (e.g., Zerynthia cassandra [Geyer, 1828], Zinetti et al, 2013; and Euchloe bazae Fabiano, 1993, Escuer et al, 2022) and corroborated or newly discovered ones using genomic data ( Euphilotes battoides allyni [Shields, 1975], Dupuis et al, 2020; and Z. cassandra , Ebdon et al, 2021). Currently, population genetics approaches and, mainly, COI barcoding programmes (e.g., Dincă et al, 2021) have contributed to identifying cryptic species complexes, establishing evolutionary units, and assessing the evolutionary uniqueness of populations.…”