Cross-Eurasian and altitudinal distribution of lotic mayflies – species with wider altitudinal ranges have narrower geographical distribution

Abstract

-The aim of the study was to test the hypothesis that patterns of cross-Eurasian longitudinal distribution of lotic mayflies are determined by species' ecological requirements and the presence of the West Siberian Lowland. In particular, the objective was to test whether this great lowland is an environmental barrier preventing longitudinal dispersal of the rheophilic (i.e., preferring fast-running highland waters), but not the potamophilic (i.e., preferring slow-current lowland waters) mayflies, as its entire territory contains no rapidly-flowing streams suitable for rheophilic species. This hypothesis was tested indirectly by comparison of altitudinal ranges of species characterised by different cross-Eurasian distribution patterns (mainly East Palaearctic and Transpalaearctic species distributed over the Asian part of Palaearctica and entire Palaearctica respectively). The material used for the analyses was collected in the centre of Eurasia, southwestern Siberia, Russia. The region covered both lowland and mountain territories. The studied biogeographical groups of mayflies have distinctly different altitudinal distribution: the Transpalaearctic species inhabit lowland watercourses only, while the East Palaearctic species inhabit the entire altitudinal range with most of the species preferring high elevations (on average 700 m a.s.l.). These results confirmed the stated hypothesis and showed that for most of the East Palaearctic (but not Transpalaearctic) species the West Siberian Lowland can be an environmental barrier preventing their westward dispersal and therefore precluding mixing of the East and West Palaearctic rheophilic faunas. However, possible alternative hypotheses cannot be ruled out, as altitudinal ranges of some of these species do not fall out of the elevation range of the West Siberian Lowland. Remarkably, the East Palaearctic species, which by definition have narrower distribution than the Transpalaearctic species, have broader altitudinal ranges than the Transpalaearctic species. This pattern is related to the altitudinal Rapoport effect recently detected for mayfly distribution over the river systems.

Distribution and ecology of the mayflies (Ephemeroptera) of Flanders (Belgium)

“…Neither Flanders nor Belgium contains any endemic species and most species recorded in Flanders have a West Palaearctic or even a Transpalaearctic distribution, which is usually the case for lowland species (Beketov, 2009). Using the categories proposed by the IUCN Species Survival Commission (IUCN Species Survival Commission, 1994) and adapted for Flanders (Maes and Van Swaay, 1997;Maes et al, 2003), mayflies were divided into categories according to their rarity.…”

www.freshwaterecology.info – An online tool that unifies, standardises and codifies more than 20,000 European freshwater organisms and their ecological preferences

“…Freshwaterecology.info is increasingly recognised as a source of reference regarding ecoregional distribution, taxonomical information and ecological preferences (e.g., Beketov, 2009;Chang et al, 2014;Gebhardt et al, 2010;Holzenthal et al, 2010;Previšić et al, 2014;Stamp et al, 2010;Weiss et al, 2011). In the following paragraphs we present some examples of how scientists have used the database in their research.…”

A contribution to mayfly studies of Western Mongolia (Insecta, Ephemeroptera)

“…In addition, three new species were recorded for Mongolia for the first time, Raptobaetopus tenellus , Caenis luctuosa and Caenis rivulorum . Raptobaetopus tenellus is a Transpalaearctic (also referred as Entire Palaearctica, Beketov (2009) ) species ( Bauernfeind and Soldán 2012 ). Distribution of this species is known from west Palaearctic (Iberian Peninsula through Europe to the northern Ural Mountains) to Eastern Palaearctic (lower Ob' River and basin in Siberia to Primoriye region) ( Bauernfeind and Soldán 2012 ).…”