Range‐constrained co‐occurrence simulation reveals little niche partitioning among rock‐dwelling Montenegrina land snails (Gastropoda: Clausiliidae)

Abstract

AimTaxon co-occurrence analysis is commonly used in ecology, but it has not been applied to range-wide distribution data of partly allopatric taxa because existing methods cannot differentiate between distribution-related effects and taxon interactions. Our first aim was to develop a taxon co-occurrence analysis method that is also capable of taking into account the effect of species ranges and can handle faunistic records from museum databases or biodiversity inventories. Our second aim was to test the independence of taxon co-occurrences of rock-dwelling gastropods at different taxonomic levels, with a special focus on the Clausiliidae subfamily Alopiinae, and in particular the genus Montenegrina.LocationBalkan Peninsula in south-eastern Europe (46N–36N, 13.5E–28E).MethodsWe introduced a taxon-specific metric that characterizes the occurrence probability at a given location. This probability was calculated as a distance-weighted mean of the taxon’s presence and absence records at all sites. We applied corrections to account for the biases introduced by varying sampling intensity in our dataset. Then we used probabilistic null-models to simulate taxon distributions under the null hypothesis of no taxon interactions and calculated pairwise and cumulated co-occurrences. Independence of taxon occurrences was tested by comparing observed co-occurrences to simulated values.ResultsWe observed significantly fewer co-occurrences among species and intra-generic lineages of Montenegrina than expected under the assumption of no taxon interaction.Main conclusionsFewer than expected co-occurrences among species and intrageneric clades indicate that species divergence preceded niche partitioning. This suggests a primary role of non-adaptive processes in the speciation of rock-dwelling gastropods. The method can account for the effects of distributional constraints in range-wide datasets, making it suitable for testing ecological, biogeographical, or evolutionary hypotheses where interactions of partly allopatric taxa are in question.

An integrative approach to the taxonomy and systematics within the genusMontenegrinaBoettger, 1877 (Mollusca, Gastropoda, Clausiliidae)

“…The overall topology of the DNA‐based tree was already introduced by Fehér et al. (2018). Mason et al.…”

Patterns and processes in a non‐adaptive radiation: Alopia (Gastropoda, Clausiliidae) in the Bucegi Mountains

“…Adaptive radiations, which are the result of ecological speciation by divergent selection and a rapid adaptation of incipient species to different niches, have been studied in detail, for example the Darwin's finches in the Galápagos Islands (Grant & Grant, ), Anolis lizards of the Caribbean (Losos, ) or cichlid fish in Africa (Seehausen, ). In contrast, non‐adaptive radiations, in which diversification is not accompanied by adaptation into different niches, but results in a group of usually allopatric species occupying similar niches (Dominey, ; Fehér et al, ; Gittenberger, ; Rundell & Price, ) have been neglected for a long time. However, the importance of non‐adaptive radiations may be underestimated.…”

Evolution of a dextral lineage by left-right reversal inCristataria(Gastropoda, Pulmonata, Clausiliidae)

“…Recently, it has been demonstrated that early phylogenetic divergence in rock-dwelling door snails is driven primarily by non-adaptive factors (Fehér et al, 2018). As there is no reason to assume that one of the chiral directions in Cristataria would be more advantageous than the other, it seems reasonable assuming that a reversed phenotype become fixed in a small, spatially isolated population once its frequency exceeded 50% (van Batenburg & Gittenberger, 1996;Orr, 1991;Ueshima & Asami, 2003) and not because of any survival/reproductive advantage (Hoso et al, 2010;Johnson, Murray, & Clarke, 1993).…”