Long‐term cloud forest response to climate warming revealed by insect speciation history*

Abstract

Montane cloud forests are areas of high endemism, and are one of the more vulnerable terrestrial ecosystems to climate change. Thus, understanding how they both contribute to the generation of biodiversity, and will respond to ongoing climate change, are important and related challenges. The widely accepted model for montane cloud forest dynamics involves upslope forcing of their range limits with global climate warming. However, limited climate data provides some support for an alternative model, where range limits are forced downslope with climate warming. Testing between these two models is challenging, due to the inherent limitations of climate and pollen records. We overcome this with an alternative source of historical information, testing between competing model predictions using genomic data and demographic analyses for a species of beetle tightly associated to an oceanic island cloud forest. Results unequivocally support the alternative model: populations that were isolated at higher elevation peaks during the Last Glacial Maximum are now in contact and hybridizing at lower elevations. Our results suggest that genomic data are a rich source of information to further understand how montane cloud forest biodiversity originates, and how it is likely to be impacted by ongoing climate change.

Spatial and host related genomic variation in partially sympatric cactophagous moth species

“…Our demographic modelling approach suggested that events of interspecific gene flow also occurred during the late Pleistocene (~16.1 kya), probably as a consequence of population expansions during the transition between the last maximum glacial and early Holocene (e.g. Salces‐Castellano et al, 2021; Rodriguero et al, 2016; Tonzo et al, 2019).…”

Collective and harmonised high throughput barcoding of insular arthropod biodiversity: toward a Genomic Observatories Network for islands

“…Existing studies in this area have been limited to specific arthropod lineages, such as beetles or spiders, for which conventional taxonomical and molecular processing is time-consuming (e.g. Malumbres-Olarte et al, 2021;Antonia Salces-Castellano et al, 2020). HTS barcoding provides an opportunity to increase both the taxonomic and geographic scale of arthropod community sampling.…”

“…However it has been shown that, across multi-species comparisons, potentially idiosyncratic single marker signals within a subset of arthropod species may be outweighed by common community level signatures (e.g. Salces-Castellano et al, 2020;Scalercio et al, 2020). As the histories of individual species complexes may themselves be idiosyncratic, having noisy data across hundreds or even thousands of species may, in some cases, be more revealing of general patterns and processes in a region than deeper sequencing of a more limited number.…”

Digest: Gene flow timing uncovers a cloud forest downslope shift in warmer times*

“…In this issue, Salces‐Castellano et al. (2020) searched for clues to the connectivity dynamic of a cloud forest in an oceanic island by analyzing the evolutionary history of two populations of a beetle species tightly associated with this ecosystem. The authors proposed a novel framework to test the effect of climatic fluctuations on montane ecosystems connectivity by harnessing genomic information.…”