The dynamics of coexistence: habitat sharing versus segregation patterns among three sympatric montane vipers. (26th June 2015)

• Record Type: Journal Article
• Authors: Mebert, Konrad; Jagar, Tomaz; Grželj, Rok; Cafuta, Vesna; Luiselli, Luca; Ostanek, Erika; Golay, Philippe; Dubey, Sylvain; Golay, Joaquim; Ursenbacher, Sylvain
• Is Part Of: Biological journal of the Linnean Society. Volume 116:Number 2(2015:Oct.)
• Page Start: 364
• Page End: 376
• Publication Date: 2015-06-26
• Subjects: Biology -- Periodicals; Evolution (Biology) -- Periodicals; 570
• DOI: 10.1111/bij.12582
• Languages: English
• ISSNs: 0024-4066

Abstract

<abstract abstract-type="main" id="bij12582-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Contact zones of closely related and ecologically similar species constitute rare opportunities to study the evolutionary consequences of past speciation processes. They represent natural laboratories in which strong competition could lead to the exclusion of one species, or the various species may switch into distinct ecological niches. Alternatively, if reproductive isolation has not yet been achieved, they may hybridize. We elucidate the degree of taxon integrity by comparing genetics and habitat use of three similar‐sized congeneric viper species, <italic>Vipera ammodytes</italic>, <italic> Vipera aspis</italic>, and <italic>Vipera berus</italic>, of Nadiza Valley in western Slovenia. No hybridization was detected for either mitochondrial or nuclear genomes. Similarly, external intermediacy by a single prestudy viper (probably <italic>V. ammodytes</italic> × <italic>V. aspis</italic>) indicates that hybridization occasionally occurs, but should be very rare. Populations of the three related viperids are partially allopatric in Nadiza Valley, but they also coexist in a narrow contact zone in the montane grassland along the south‐exposed slope of Mount Stol (1673 m a.s.l.). Here, the three species that occupy areas in or near patches of rocky microhabitats (e.g. stone piles, slides, and walls) live in syntopy. However, fine‐scale measurements of structural components show partial habitat segregation, in which <italic>V. berus</italic> becomes more dominant at elevations above 1400 m and occupies mostly the mountain ridge and north‐exposed slopes of Mount Stol, <italic>V. aspis</italic> occurs below 1300 m and is the only species to inhabit stoneless patches of grass and bushes around 1000 m and lower, and <italic>V. ammodytes</italic> occurs at all elevations up to 1500 m, but is restricted to a rocky microhabitat. We suggest that a high degree of microstructure divergence, slightly different environmental niches, and a generally favourable habitat for all three viper species, keep the pressure for mis‐mating and hybridization low, although mechanisms such as reduced hybrid inferiority and temporal mating segregation cannot yet be excluded.</p> </abstract>