Biogeographers, long ago described the species richness and composition changes that occur with altitude (Humboldt, 1805; Merriam, 1894), and it is now widely recognized that both environmental conditions and historical factors play an important role in explaining such variation (Brown & Lomolino, 1998). In the case of Holarctic dung beetle assemblages, the variation in species richness and composition turnover with altitude seems to be related to replacement of one dung beetle lineage by another. Geotrupinae -but mainly Aphodiinae -species generally dominate in north-temperate regions and at high altitudes, while Scarabaeinae species dominate in the Mediterranean region and in the lowlands (see Hanski, 1986; Martin-Piera et al., 1992;Halffter et al., 1995;Jay-Robert et al., 1997;Lobo, 2000;Lobo & Halffter, 2000;Errouissi et al., 2004;Escobar et al., 2005Escobar et al., , 2006. This may be the consequence of the colonization of the south by northern lineages, favoured by the climate changes that occurred in the Pleistocene (Jay-Robert et al., 1997;Lobo & Halffter, 2000;Escobar et al., 2006). Unfortunately, data on the distribution of dung beetles with altitude in the Palaearctic are only for some western European regions (France and the Iberian Peninsula); there is no reliable, standardized data from the eastern European mountains. This study of the variation with altitude in faunistic composition and species richness in the western Rhodopes Mountains, near the oriental Euromediterranean region, aims to: corroborate patterns established for other western European mountain assemblages; discuss the general characteristics of these mountain assemblages; and determine the altitudinal variation in species richness, abundance and composition of the main dung beetle groups. METHODS Studied regionThe Western Rhodopes, in south-central Bulgaria, occupy an area of more than 8,000 square kilometres. The western and eastern peaks of the massif (the highest is Golyam Perelik, 2191 m), are separated by the Vucha River valley. Its complex relief and broad surface, together with its connection to the highest massif of the Balkan Peninsula and its proximity to the Mediterranean Sea, determine its diverse climate. In the middle and high mountain regions, which include most of the area, the average annual temperature is 5-9°C. Maximum precipitation is evenly distributed, in May-June and November. Highly diverse habitats (e.g. forest, meadow, riverside, limestone, sandy, stony, gravel, as well as various types of ecotones) coexist in the region. Four main vegetation formations are distributed along an altitude gradient: (i) xero-mesophilous, broad-leaved woodlands and shrubs of Submediterranean type; (ii) mesophilous, broadleaved woodlands of Nemoral type; (iii) mesophilous, coniferous forest of Boreal type; and (iv) open, high-mountain mesophilous pastures of Alpine type. A local peculiarity is the predominance of mesophilous, coniferous forests of Boreal type, between 800 and 1800 m; to a large extent they have displaced the seco...
The phylogenetic placement of Jekelius brullei (Jekel, 1866) and J. punctulatus (Jekel, 1866) (Coleoptera: Geotrupidae) was assessed using mitochondrial and nuclear molecular data to discern contrasting nomenclatural views provided by López-Colón (1996) and the Catalogue of Palaearctic Coleoptera (Löbl et al. 2006). Our results support both the monophyletic and classification status of the genus Jekelius López-Colón, 1989; and the splitting of the genus into the subgenera Jekelius López-Colón, 1989 and Reitterius López-Colón, 1996. The basal phylogenetic placement of these two species also suggests an oriental origin for Jekelius within the western Palaearctic region. Finally, we include a potential distributional map of Jekelius (Reitterius) punctulatus (Jekel, 1866) based on an exhaustive search of occurrence data.
We compile the available georeferenced information on Bulgarian Scarabaeus species, including both bibliographic and natural history data to provide basic ecological and biogeographical information as well as maps of climatically favourable areas (potential distributions) for each one of the species. Scarabaeus species in Bulgaria seem to be generally distributed across low altitude areas mainly under warm temperate or Mediterranean conditions, although S. variolosus appears to be the species adapted to the warmest conditions and S. armeniacus inhabits areas of medium altitude. Our results indicate that it is necessary to carry out an extra survey effort in the northern lowlands, away the Stara Planina Mts. in order to validate current climatically suitable territories for some species. However, the recent land use transformations of these lowland areas, together with the general decline of roller dung beetle populations, suggest that this validation may not be possible.
We analyzed the altitudinal change in dung beetle species richness and the relative proportion of higher taxa, as well as the turnover in the type of distribution and range size of species in two mountain chains located at the two extremes of Europe (Western Rhodopes Mountains and the Iberian Central System). Both mountain ranges showed a clear substitution among higher taxa (Aphodiinae-Geotrupinae vs. Scarabaeidae) and species richness variation with the altitude was similar. We suggest that East European dung beetle assemblages are conditioned by a horizontal colonization process in which mountains had been reached in relatively recent geological time by elements coming from different latitudes. In spite of these convergences, Rhodopes dung beetle assemblages are characterized by a significantly lower proportion of narrowly distributed species and a lower relevance of Aphodiinae species in lowland places. Although these divergences can be partially attributed to the dissimilar sampling effort accomplished in both regions, we suggest that the low number on narrowly distributed species could be due to the different role of these two mountain zones as refuges during glaciar-interglaciar Pleistocene cycles.
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