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Mediterranean Wetlands (mediterranean + wetland)
Selected AbstractsDispersal of freshwater invertebrates by large terrestrial mammals: a case study with wild boar (Sus scrofa) in Mediterranean wetlandsFRESHWATER BIOLOGY, Issue 11 2008BRAM VANSCHOENWINKEL Summary 1.,Many invertebrates inhabiting insular aquatic habitats rely on external agents or vectors to disperse. Besides water connections and wind, waterfowl and amphibians are known to mediate passive dispersal of freshwater invertebrates. However, the possibility of dispersal by terrestrial mammals has been largely overlooked. 2.,We investigated the potential of both external and internal zoochorous dispersal of aquatic invertebrates by the wild boar (Sus scrofa) in Mediterranean wetlands in the Camargue (France). As wild boar frequently visit wetlands for feeding and wallowing purposes, we hypothesized that they may be important passive dispersal vectors of aquatic invertebrates at a local scale. Dried mud was collected from selected ,rubbing trees' used by boars to dispose of parasites. Additionally, faecal pellets were collected from different locations in the wetland area. 3.,Seventeen freshwater invertebrate taxa including rotifers, cladocerans, copepods and ostracods hatched from sediment obtained from ,rubbing trees', while invertebrates hatching from dried faeces (10 taxa) were mainly rotifers. Dispersing invertebrates were collected up to 318 m from a nearest potential dispersal source. Both abundance and richness of invertebrates significantly decreased with dispersal distance. 4.,Our results demonstrate that large mammals such as wild boar can act as dispersal vectors of aquatic invertebrates at a local scale in the wetland area of the Camargue and suggest that external transport may be quantitatively more important than internal transport. As wallowing (mud bathing) is common in many terrestrial mammals, this mode of dispersal may be quite widespread. [source] Sample size and the detection of a hump-shaped relationship between biomass and species richness in Mediterranean wetlandsJOURNAL OF VEGETATION SCIENCE, Issue 2 2006J.L. Espinar Abstract Questions: What is the observed relationship between biomass and species richness across both spatial and temporal scales in communities of submerged annual macrophytes? Does the number of plots sampled affect detection of hump-shaped pattern? Location: Doñana National Park, southwestern Spain. Methods: A total of 102 plots were sampled during four hydrological cycles. In each hydrological cycle, the plots were distributed randomly along an environmental flooding gradient in three contrasted microhabitats located in the transition zone just below the upper marsh. In each plot (0.5 m × 0.5 m), plant density and above- and below-ground biomass of submerged vegetation were measured. The hump-shaped model was tested by using a generalized linear model (GLM). A bootstrap procedure was used to test the effect of the number of plots on the ability to detect hump-shaped patterns. Result: The area exhibited low species density with a range of 1,9 species and low values of biomass with a range of 0.2 -87.6 g-DW/0.25 m2. When data from all years and all microhabitats were combined, the relationships between biomass and species richness showed a hump-shaped pattern. The number of plots was large enough to allow detection of the hump-shaped pattern across microhabitats but it was too small to confirm the hump-shaped pattern within each individual microhabitat. Conclusion: This study provides evidence of hump-shaped patterns across microhabitats when GLM analysis is used. In communities of submerged annual macrophytes in Mediterranean wetlands, the highest species density occurs in intermediate values of biomass. The bootstrap procedure indicates that the number of plots affects the detection of hump-shaped patterns. [source] Niche breadth rather than reproductive traits explains the response of wetland monocotyledons to land-cover changeAPPLIED VEGETATION SCIENCE, Issue 1 2009Joan Pino Abstract Question: We hypothesised that, even within the same plant functional group, there are specific distributions in land-cover classes and with land-cover change that are associated with niche breadth rather than reproductive strategy, and that the broader the niche of the species the better they cope with different land-cover classes and changes over time. Location: The Llobregat Delta (Barcelona, Spain). Methods: We analysed the distribution pattern of eight coexisting wetland perennial monocotyledons within human disturbance classes (obtained from the classification of land-cover categories in relation to their level of human disturbance) and changes in such classes from 1956 to 1999. We then compared species regional abundance and distribution patterns with seed dispersal type (wind dispersed versus non-wind dispersed species), vegetative spread (tussock versus caespitose-running species), and niche breadth (the number of phytosociological alliances in which each species is found). Results: Regional abundance of the species was positively related to niche breadth, but was independent of reproductive traits. Similarly, distribution in human disturbance classes and their changes were associated with niche breadth rather than reproductive traits. In general, the more specialist the species, (i) the more they are concentrated in natural habitats, (ii) the less land-cover changes they are able to cope with, and (iii) the more they are restricted to stable change types, particularly to longstanding natural areas. Conclusions: Ecological plasticity rather than dispersal capacity of dominant perennial monocotyledons determines their regional abundance and their ability to cope with recent and future land-cover changes in Mediterranean wetlands. As habitat specialists are less resistant to landscape change than generalists, floristic homogenisation may progress in these habitats with the likely scenario of increasing land-cover turnover. [source] Loss of Ostracoda biodiversity in Western Mediterranean wetlandsAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 3 2008José M. Poquet Abstract 1.The coastal area of Valencia (Spain) in the Western Mediterranean is rich in freshwater and brackish wetlands. These areas are mostly protected for bird conservation but are also highly affected by human impacts. Six shallow lakes located in Ramsar wetland sites of this area were studied in order to assess past and present ostracod biodiversity and relate it to the status of the lakes, taking into consideration the indicator value of these easily fossilizable crustaceans. 2.In all the wetlands studied, ostracod taphocoenoses showed much higher species richness than the corresponding biocoenoses. This is expected from the time accumulative character of the taphocoenosis, but the trend is clearly evident in the most disturbed sites which indicated loss of ostracod diversity owing to human impacts. 3.By considering the ecology of most frequent species, multivariate ordination of both tapho- and biocoenoses showed trends within and between lakes in their limnological status, which were related mainly to water chemistry, and also to temporality and eutrophication to a certain extent. Some lakes have apparently lost most of their past ostracod community owing to an increasing trophic status in some cases and to modifications of the hydrological regime in others. Copyright © 2007 John Wiley & Sons, Ltd. [source] | |||||||||||||