Giuseppe Alfonso

Mitochondrial DNA Regionalism and Historical Demography in the Extant Populations of Chirocephalus kerkyrensis (Branchiopoda: Anostraca)

Background Mediterranean 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 Findings We 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/Significance Multiple 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.

Does lake age affect zooplankton diversity in Mediterranean lakes and reservoirs? A case study from southern Italy

Zooplankton assemblages of 51 lacustrine environments located in the middle of the Mediterranean Region were analysed to evaluate the existence of an ‘age effect’ in determining their structure. 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 opportunity to evaluate the possible short-term effects of ageing on the structure of their zooplankton. A comparison of assemblages in the two regions by PERMANOVA and nMDS revealed that they are quite different; therefore they were analysed separately. An explorative analysis on the possible 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 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 watershed.

Using crustaceans to identify different pond types. A case study from the Alta Murgia National Park, Apulia (South-eastern Italy)

The aim of this study was to test the effectiveness of crustaceans in the identification of different pond types, including ‘Mediterranean Temporary Ponds’ (sensu ‘Habitats’ Directive) and ponds characterised by a range of hydroperiods. Thus, we performed a limnological study in the Alta Murgia National Park (central Apulia), conducting a three-year monitoring programme in 19 ponds, both temporary and permanent. Occurrence data for macrophytes and quantitative samples of crustaceans were collected contemporaneously with measures of water variables and environmental features. Based on macrophyte assessment, half of the studied waterbodies were found to include Mediterranean Temporary Pond priority habitats, and the possible relationships with the crustacean assemblages were analysed. All ponds were grouped into three different classes depending on their hydroperiod. Data analysis revealed that (i) there was a significant relationship between the distribution of crustaceans and macrophytes; (ii) crustacean richness was highest in ponds belonging to the shortest hydroperiod class considered and (iii) the different hydroperiod classes were associated with specific crustacean assemblages. This study indicates that crustaceans—in addition to macrophytes—can be used as an effective tool for the identification of different pond types.

Diversity patterns and biogeography of Diaptomidae (Copepoda, Calanoida) in the Western Palearctic

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 post-glacial recolonization from southern refugia in the East, where mountain chains are north–south oriented and therefore less effective as barriers.

Molecular and morphological data suggest weak phylogeographic structure in the fairy shrimp Streptocephalus torvicornis (Branchiopoda, Anostraca)

Inland aquatic organisms almost ubiquitously display a pattern of marked provincialism characterized by substantial population differentiation and genealogical discontinuities. This is the result of strong priority effects and local adaptation following dispersal and colonization of new habitats. We present a case that defies this biogeographic paradigm. We have investigated the phylogeography of the fairy shrimp Streptocephalus torvicornis across its circum-Mediterranean and Eurasian distribution. Based on three independent datasets, namely sequence variation at 12S and 16S rRNA, cyst morphology and male second antenna characters, we discern a pattern of extensive genetic and morphological homogeneity pointing to unhindered gene flow and widespread connectivity among populations. These intriguing findings may provisionally be explained by (i) a high dispersal frequency overwhelming the ability of a population to maintain resource monopolization, (ii) an outbreeding vigour opportunity offered to secondary immigrants, (iii) an ecological equivalence of genotypes generating long-term immigration–extinction equilibria and buffering genetic diversity over spatial scales, (iv) enhanced bird-mediated dispersal in open habitats as opposed to ponds surrounded by forests or shrub, or (v) a shallow population history with little time for substantial genetic differentiation.

Diversity and distribution of large branchiopods (Branchiopoda: Anostraca, Notostraca, Spinicaudata) in Apulian ponds (SE Italy)

Abstract A first extensive survey in the inland waters of Apulia was carried out with the aim to detect occurrences of large branchiopods and to assess their diversity and distribution in the region. Samples were gathered during each wet season between 2004 and 2016, in several cases with multiple collections per site in different years. A total of 240 water bodies were studied. Based on a careful review of the available literature data and the results of this survey, 10 large branchiopod species (six Anostraca, two Notostraca, two Spinicaudata) are reported to occur in the Apulian inland waters at present. The findings of the spinicaudatans Leptestheria mayeti and Cyzicus tetracerus and of the anostracan Streptocephalus torvicornis are new records for the Italian mainland. Different species assemblages were found to correspond to specific sets of environmental conditions and habitat types. The diversity of large branchiopods in the region indicates the distinctive role of the Apulian inland waters and their ecological importance in the biogeography of the crustacean inland water fauna in the Mediterranean area. The conservation status of the environments where the species were collected is also discussed.

The diaptomid fauna of Israel (Copepoda, Calanoida, Diaptomidae), with notes on the systematics of Arctodiaptomus similis (Baird, 1859) and Arctodiaptomus irregularis Dimentman & Por, 1985 stat. rev

BackgroundTo date, only scarce information is available about the diaptomid copepods of the Middle East despite the ecological and biogeographical importance of the family Diaptomidae in the inland waters of the Holarctic region. Moreover, the taxonomic status of some of the taxa occurring in the area is in need of revision. We studied crustaceans collected from temporary and permanent lentic water bodies in Israel with the aim of providing an updated census of the diaptomid copepods occurring in the country. Furthermore, we morphologically and genetically analysed samples of Arctodiaptomus similis s.l. to shed light on its taxonomy.ResultsFive diaptomid taxa were collected during this survey. Among these, Phyllodiaptomus blanci is new for the country and the whole circum-Mediterranean area and might be an allochthonous species of eastern origin. Within the collected samples, we singled out two parapatric groups of populations within A. similis s.l.; these consistently differ both based on morphology (chaetotaxy of the left male antennule) and molecular data (divergence over 17% at the mitochondrial gene for the cytochrome b). We thus attribute the full species rank to Arctodiaptomus irregularis Dimentman & Por, 1985 stat. rev., originally described as a subspecies of the widespread species Arctodiaptomus similis (Baird, 1859).ConclusionsWe critically evaluated all species hitherto reported for Israeli inland waters. Considering both the confirmed literature data and the new findings, Israeli diaptomid fauna is composed of at least seven species. However, the need for further surveys in the Middle East and for detailed systematic revisions of some controversial taxa is stressed. Our results on the systematics of A. similis s.l. illustrate the importance of implementing molecular analyses when investigating diversity patterns of groups which are difficult to resolve based on morphology alone.