Diaptomid copepods are an important component of biodiversity in inland aquatic ecosystems worldwide but to date little is known about the historical and ecological factors that determined their current distribution. In the present paper, a critical review of the available literature on diaptomid species distribution in the Western Palearctic was performed, and a biogeographical analysis was carried out on the roles that spatial, current environmental, and historical (paleoclimatic) factors played on their actual distribution in this large area. The results show a clear pattern of colonization which is only partially overlapping what has been recently proposed for other terrestrial and aquatic taxa. Disentangling beta diversity into its turnover and nestedness components, we hypothesized a complex post-glacial pattern of recolonization of the higher latitudes, encompassing the importance of extra-Mediterranean refugia in the West (due to mountain chains which represent effective barriers for recolonization coming from the Italian and Iberian peninsulas) and a more typical pattern of postglacial recolonization from southern refugia in the East, where mountain chains are north-south oriented and therefore less effective as barriers.
BackgroundMediterranean temporary water bodies are important reservoirs of biodiversity and host a unique assemblage of diapausing aquatic invertebrates. These environments are currently vanishing because of increasing human pressure. Chirocephalus kerkyrensis is a fairy shrimp typical of temporary water bodies in Mediterranean plain forests and has undergone a substantial decline in number of populations in recent years due to habitat loss. We assessed patterns of genetic connectivity and phylogeographic history in the seven extant populations of the species from Albania, Corfu Is. (Greece), Southern and Central Italy.Methodology/Principal FindingsWe analyzed sequence variation at two mitochondrial DNA genes (Cytochrome Oxidase I and 16s rRNA) in all the known populations of C. kerkyrensis. We used multiple phylogenetic, phylogeographic and coalescence-based approaches to assess connectivity and historical demography across the whole distribution range of the species. C. kerkyrensis is genetically subdivided into three main mitochondrial lineages; two of them are geographically localized (Corfu Is. and Central Italy) and one encompasses a wide geographic area (Albania and Southern Italy). Most of the detected genetic variation (≈81%) is apportioned among the aforementioned lineages.Conclusions/SignificanceMultiple analyses of mismatch distributions consistently supported both past demographic and spatial expansions with the former predating the latter; demographic expansions were consistently placed during interglacial warm phases of the Pleistocene while spatial expansions were restricted to cold periods. Coalescence methods revealed a scenario of past isolation with low levels of gene flow in line with what is already known for other co-distributed fairy shrimps and suggest drift as the prevailing force in promoting local divergence. We recommend that these evolutionary trajectories should be taken in proper consideration in any effort aimed at protecting Mediterranean temporary water bodies.
The currently available knowledge on biodiversity and species distribution of Italian fauna still presents some gaps to be filled, in particular in the southern part of the country. This study represents the first survey aimed at assessing the presence and distribution of Calanoida in inland waters of Apulia (south-eastern Italy). The research lasted five years and led to the mapping of 121 inland water bodies, most of which are characterized by temporary hydroperiods. Fifty-five of the sampled sites hosted at least one calanoid species, and 48 sites (among the 55 sites hosting Calanoida) are temporary water bodies. Thirteen calanoid species were detected in total; several of these are first records for Apulia and three species are new records for mainland Italy. The efficiency of the sampling effort was tested for both the entire Apulian territory and its main subareas, namely Gargano (in northern Apulia), and Salento (southern Apulia). Central Apulia showed the lowest species richness among the three sampled subareas. This is probably due to the scarcity of inland water bodies. Species composition of Apulian calanoid fauna was compared to the ones of the geographically close areas for which data are available: the other Italian faunal provinces (Alpine, Apennine, Padanian, Sardinian and Sicilian provinces) and the Balkans (Albania, Corfu, Croatia, Greece and Turkish Trace, Macedonia, Slovenia). Gargano and Salento showed a different assemblage of vicariant species but both the areas showed a remarkable presence of Mediterranean elements that, in fact, characterize the whole Apulian faunal province. The highest similarities for inland water calanoid fauna, which were observed between Gargano and the Apennine province, and between Salento and Sicily, are discussed, along with the total assessment of the whole Apulian calanoid fauna
Zooplankton assemblages of 51 lacustrine\ud environments located in the middle of the Mediterranean Region were analysed to evaluate the existence of an ‘age effect’ in determining their structure.\ud The analysed datasets refer to two different geographic areas, one comprising 30 natural and artificial lakes in Sicily and the other an arrangement of 21 analogous aquatic ecosystems located at the bottom of the Italian Peninsula, a more pristine area called Southern Apennine region. Most of the natural lakes are of post-glacial origin. The artificial lakes in both datasets were built in the last century and offer the\ud opportunity to evaluate the possible short-term effects of ageing on the structure of their zooplankton. A\ud comparison of assemblages in the two regions by PERMANOVA and nMDS revealed that they are\ud quite different; therefore they were analysed separately.\ud An explorative analysis on the possible\ud relationship between biological data and environmental data (including lake age) was performed on both datasets using DISTLM. The presence of an ‘age effect’ emerged only in the subset of artificial lakes of the Southern Apennine region; accordingly it was\ud tested more in detail with an a posteriori PERMANOVA analysis in the subset of reservoirs that resulted positive in the first test. SIMPER allowed us to single out the main species responsible of changes in the zooplankton along the selected age groups. No age effect was evident in the Sicilian water bodies, where other variables, such as conductivity, trophic state, urbanisation and water level fluctuations proved to have a major role in shaping zooplankton assemblages. The results showed that the age effect is: (i) detectable only at a time scale of decades; (ii) masked by the human impact in the\ud watershed
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