975 resultados para Sterry, Paul: Birds of the Mediterranean : a photographic guide
Resumo:
The pressures for land use change have led to an increasing isolation of habitat remnants throughout the world. The goal of this study was to estimate the population size and density of some endemic and threatened species in a nature reserve in the Cerrado biome. One hundred and thirty four point transects were undertaken at the Estacao Ecologica de Itirapina (EEI), one of the last natural grassland savannah remnants in Sao Paulo state, in the south-east of Brazil between September and December 2006 and densities estimated for seven species (four endemic to the Cerrado, one near-endemic and two grassland specialists). Neither species reached the minimum viable population size of 500-5000 individuals. Four species, White-banded Tanager, White-rumped Tanager, Black-throated Saltator and Sharp-tailed Tyrant have populations ranging from 112 to 248 individuals, while the other species have a low population (< 60 individuals). The mean densities of Sharp-tailed Tyrant and Cock-tailed Tyrant in the EEI grassland showed similar values to those observed in larger areas of the Cerrado, which may indicate that the EEL grassland area is well conserved. In spite of the restricted size of the EEI, small areas can maintain some endemic and threatened bird populations, thus contributing to local biodiversity and the ecological processes in the region. The capacity of fragments of Cerrado (similar to 2,000 ha) to maintain populations of endemic and threatened bird species is unlikely to be effective in the long term.
Resumo:
Elasmobranchs are an important by-catch of commercial fisheries targeting bony fishes. Fisheries targeting sharks are rare, but usually almost all specimen bycatched are marketed. They risk extinction if current fishing pressure continues (Ferretti et al., 2008). Accurate species identification is critical for the design of sustainable fisheries and appropriate management plans, especially since not all species are equally sensitive to fishing pressure (Walker & Hislop 1998). The identification of species constitutes the first basic step for biodiversity monitoring and conservation (Dayrat B et al., 2005). More recently, mtDNA sequencing has also been used for species identification and its use has become widespread under the DNA Barcode initiative (e.g. Hebert et al. 2003a, 2003b; Ward et al. 2005, 2008a; Moura et al 2008; Steinke et al. 2009). The aims of this work were: 1) identify sharks and skates species using DNA barcode; 2) compare species of different provenance; 3) use DNA barcode for misidentified species. Using DNA barcode 15 species of sharks (Alopias vulpinus, Centrophorus granulosus, Cetorhinus maximus, Dalatias licha, Etmopterus spinax, Galeorhinus galeus, Galeus melastomus, Heptranchias perlo, Hexanchus griseus, Mustelus mustelus, Mustelus punctulatus, Oxynotus centrina, Scyliorhinus canicula Squalus acanthias, Squalus blainville), 1 species of chimaera (Chimaera monstrosa) and 21 species of rays/skayes (Dasyatis centroura, Dasyatis pastinaca, Dasyatis sp., Dipturus nidarosiensis, Dipturus oxyrinchus, Leucoraja circularis, Leucoraja melitensis, Myliobatis aquila, Pteromylaeus bovinus, Pteroplatytrygon violacea, Raja asterias, Raja brachyura, Raja clavata, Raja miraletus, Raja montagui, Raja radula, Raja polystigma, Raja undulata, Rostroraja alba, Torpedo marmorata, Torpedo nobiliana, Torpedo torpedo) was identified.
Resumo:
The growing need to assess the environmental status of the Mediterranean coastal marine habitats and the large availability of data collected by Reef Check Italia onlus (RCI) volunteers suggest the possibility to develop innovative and reliable indices that may support decision makers in applying conservation strategies. The aims of this study were to check the reliability of data collected by RCI volunteers, analyse the spatial and temporal distribution of RCI available data, resume the knowledge on the biology and ecology of the monitored species, and develop innovative indices to asses the ecological quality of Mediterranean subtidal rocky shores and coralligenous habitats. Subtidal rocky shores and coralligenous were chosen because these are the habitats more attractive for divers; therefore mlst data are referring to them, moreover subtidal rocky bottom are strongly affected by coastal urbanisation, land use, fishing and tourist activities, that increase pollution, turbidity and sedimentation. Non-indigenous species (NIS) have been recognized as a major threat to the integrity of Mediterranean native communities because of their proliferation, spread and impact on resident communities. Monitoring of NIS’ spreading dynamics at the basin spatial scale is difficult but urgent. According to a field test, the training provided by RCI appears adequate to obtain reliable data by volunteers. Based on data collected by RCI volunteers, three main categories of indices were developed: indices based on species diversity, indices on the occurrence non-indigenous species, and indices on species sensitive toward physical, chemical and biological disturbances. As case studies, indices were applied to stretches of coastline defined according to management criteria (province territories and marine protected areas). The assessments of ecological quality in the Tavolara Marine Protected Area using the species sensitivities index were consisten with those previously obtained with traditional methods.
Resumo:
A high-resolution biochronology is presented for the Late Quaternary of the central Mediterranean. In the Late Pleistocene-Holocene successions three assemblage zones are distinguished on the basis of frequency patterns of planktic foraminifera. The age of these zones is determined by Accelerator Mass Spectrometry (AMS)14C dating. The zonal boundaries are dated at 12,700 yr B.P. (the end of Termination Ia) and 9600 yr B.P. (the start of Termination Ib), respectively. The AMS dates show that major changes in the planktic and benthic realms occurred synchronously over wide areas, although records of individual species may show important regional differences. In the studied areas, resedimentation processes revealed by anomalous successions of14C dates, play a far more important role than indicated by the sedimentological and micropaleontological data. Possibly these processes contribute to the very high accumulation rates in the glacial Zone III. Although the AMS technique has increased the accuracy of14C-measurements, admixture of older carbonate may still lead to substantial age differences between areas with different sedimentary regimes.