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Southern Portugal (southern + portugal)
Selected AbstractsAssessing biotic integrity in a Mediterranean watershed: development and evaluation of a fish-based indexFISHERIES MANAGEMENT & ECOLOGY, Issue 4 2008M. F. MAGALHÃES Abstract, Biological indicators for Mediterranean rivers are poorly developed. This study evaluates the effectiveness of the Index of Biotic Integrity approach (IBI) with fish assemblages in the Guadiana catchment, a typical Mediterranean watershed in Southern Portugal. Reference sites were selected from a set of 95 sites, using a multivariate approach. Fifty-five candidate metrics were screened for range, responsiveness, precision and redundancy. Final metrics included: proportion of native fish, number of intolerant and intermediate species, number of invertivore native fish, number of phyto-lithophilic and polyphilic species, and catches of exotics. The IBI scores correlated with composite gradients of human impact and differed significantly between reference and non-reference sites. Application of the IBI to an independent validation set with 123 sites produced results congruent with the development set and repeatable assessments at 22 sites showed concordance in IBI scoring. This application highlights the effectiveness of the IBI approach even with fish assemblages of limited diversity and ecological specialisation as in Mediterranean streams. [source] Fatal Israeli Spotted Fever in a UK Traveler to South PortugalJOURNAL OF TRAVEL MEDICINE, Issue 2 2008Joshua T.Y. Chai MB Bchir A 63-year-old previously healthy woman developed a severe systemic infection 5 days after returning from a holiday to Southern Portugal. She subsequently died, and polymerase chain reaction of a blood sample was positive for Rickettsia conorii ssp israeliensis. The prevalence of severe forms of this illness in the Mediterranean Basin is discussed. [source] Fish assemblages and rapid colonization after enlargement of an artificial reef off the Algarve coast (Southern Portugal)MARINE ECOLOGY, Issue 4 2008Francisco Leitão Abstract Artificial reefs (ARs) have been deployed in Algarve (Southern Portugal) coastal waters to contribute to the sustainability of local nearshore fisheries. Herein, we describe the colonization process of the recently deployed Faro/Ancão AR, and assess the time until the fish assemblage reaches stability and their seasonal patterns. In addition, we compare the results from the present study with those previously reported for an older AR. The fish assemblages were monitored monthly over a 2-year period by means of visual census. A rapid increase in fish colonization occurred within the first 4 months. After this initial period the assemblage structure showed high similarity (> 73%). The high rate of colonization of the AR was related to the maturity already achieved by the nearby 14-year-old AR and to the fish migration from the Ria Formosa lagoon, a nearby nursery habitat. The reef fish assemblage structure showed a seasonal pattern, mainly associated with recruitment episodes of occasional demersal species (Boops boops, Trachurus trachurus and Pagellus spp.) in spring and summer. A total of 66% of the species found in AR are of commercial and recreational importance. The overall mean density and biomass were 2.8 ind·m,3 and 207 g·m,3. The occasional demersal species accounted for 42% of the fish density. The most important species in terms of biomass belong to the Sparidae family along with Dicentrarchus labrax. The fish assemblage of the new ARs showed higher mean number of species, diversity, density and biomass values than those reported for the older AR. This result was associated with enlargement of the AR area and with the fishing exploitation of the isolated, small and patchy old AR. Moreover, the high biomass values recorded in the new ARs were mainly due to the increased density of D. labrax after AR enlargement. The results of the present study are used to define guidelines for suitable management strategies for the AR areas that are exploited by the local commercial and recreational fisheries. [source] Pedotransfer functions for solute transport parameters of Portuguese soilsEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 4 2001M. C. Gonc, alves Summary The purpose of this study is to quantify solute transport parameters of fine-textured soils in an irrigation district in southern Portugal and to investigate their prediction from basic soil properties and unsaturated hydraulic parameters. Solute displacement experiments were carried out on 24 undisturbed soil samples by applying a 0.05 m KCl pulse during steady flow. The chloride breakthrough curves (BTCs) were asymmetric, with early breakthrough and considerable tailing characteristic of non-equilibrium transport. The retardation factor (R), dispersion coefficient (D), partitioning coefficient (,), and mass transfer coefficient (,) were estimated by optimizing the solution of the non-equilibrium convection,dispersion equation (CDE) to the breakthrough data. The solution could adequately describe the observed data as proved by a median of 0.972 for the coefficient of determination (r2) and a median for the mean squared error (MSE) of 5.1 × 10,6. The median value for R of 0.587 suggests that Cl, was excluded from a substantial part of the liquid phase. The value for , was typically less than 0.5, but the non-equilibrium effects were mitigated by a large mass transfer coefficient (, > 1). Pedotransfer functions (PTFs) were developed with regression and neural network analyses to predict R, D, , and , from basic soil properties and unsaturated hydraulic parameters. Fairly accurate predictions could be obtained for logD (r2 , 0.9) and , (r2 , 0.8). Prediction for R and log, were relatively poor (r2 , 0.5). The artificial neural networks were all somewhat more accurate than the regression equations. The networks are also more suitable for predicting transport parameters because they require only three input variables, whereas the regression equations contain many predictor variables. [source] Trends in NE Atlantic landings (southern Portugal): identifying the relative importance of fisheries and environmental variablesFISHERIES OCEANOGRAPHY, Issue 3 2005KARIM ERZINI Abstract Time series of commercial landings from the Algarve (southern Portugal) from 1982 to 1999 were analyzed using min/max autocorrelation factor analysis (MAFA) and dynamic factor analysis (DFA). These techniques were used to identify trends and explore the relationships between the response variables (annual landings of 12 species) and explanatory variables [sea surface temperature, rainfall, an upwelling index, Guadiana river (south-east Portugal) flow, the North Atlantic oscillation, the number of licensed fishing vessels and the number of commercial fishermen]. Landings were more highly correlated with non-lagged environmental variables and in particular with Guadiana river flow. Both techniques gave coherent results, with the most important trend being a steady decline over time. A DFA model with two explanatory variables (Guadiana river flow and number of fishermen) and three common trends (smoothing functions over time) gave good fits to 10 of the 12 species. Results of other models indicated that river flow is the more important explanatory variable in this model. Changes in the mean flow and discharge regime of the Guadiana river resulting from the construction of the Alqueva dam, completed in 2002, are therefore likely to have a significant and deleterious impact on Algarve fisheries landings. [source] Between-year variations in Little Bustard Tetrax tetrax population densities are influenced by agricultural intensification and rainfallIBIS, Issue 3 2010ANA DELGADO The Little Bustard is suffering a widespread population decline mainly due to agricultural intensification. This study evaluates the effects of intensification level, habitat availability and rainfall on the population dynamics of this species. The population density of males was monitored for 7 years (2002,2008) at 184 points located within three sites with contrasting levels of agricultural intensification in southern Portugal. Densities decreased along the intensification gradient from 8.2 to 2.3 males,/,km2. Overall, there was an approximately 50% population decline during the period 2002,2008, driven by a decline observed in one of the less intensive sites, whereas in the other two sites densities remained fairly constant. Yearly variations in male densities were influenced by intensification level, amount of grassland habitat and rainfall patterns. Thus, agricultural intensification is having a negative effect on population densities of this threatened species, particularly through the loss of grasslands (fallow fields and pastures) suitable for displaying males. The results also suggest a positive impact of rainfall on male densities, although this is more likely in grasslands within less intensive agricultural regions of poorer soil quality, where higher breeding male densities occur. Grassland habitat quality, driven by both climate and human management, probably plays a major role in the population dynamics of this threatened steppe bird in its strongholds. [source] Modelling habitat selection of Common Cranes Grus grus wintering in Portugal using multiple logistic regressionIBIS, Issue 3 2000ALDINA M.A. FRANCO Predictive models of habitat suitability for the Common Crane Grus grus in a wintering area of southern Portugal were derived using logistic multiple regression and Geographic Information Systems. The study area was characterized by landscape variables and surveyed uniformly for the presence of cranes. The most important variables were distance to roosts, to open Holm Oak woods and to villages, and the occurrence of unpaved roads, shrubby vegetation, slope and orchards. Two models were built, the second having one variable fewer than the first. The selection of the best model was based on statistical and biological criteria. Crane distribution was negatively related to: distance to open Holm Oak Quercus rotundifolia woods and roosts. Additionally, unsuitable vegetation and orchard areas are avoided. In these areas movement is difficult, food availability is reduced and the risk of predation increased. We also found that villages and roads were avoided; disturbance is a significant factor for this species. Some management guidelines are proposed for the area: (1) maintenance of open Holm Oak woodlands, (2) incentives to avoid the abandonment of traditional agriculture and pastoral use of the area, which would lead to an increase of shrubby vegetation areas, (3) preservation of suitable roosting places and (4) management of new patches of forest and orchards. [source] Weather regimes and their connection to the winter rainfall in PortugalINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 1 2005J.A. Santos Abstract Wintertime rainfall over Portugal is strongly coupled with the large-scale atmospheric flow in the Euro-Atlantic sector. A K -means cluster analysis, on the space spanned by a subset of the empirical orthogonal functions of the daily mean sea-level pressure fields, is performed aiming to isolate the weather regimes responsible for the interannual variability of the winter precipitation. Each daily circulation pattern is keyed to a set of five weather regimes (C, W, NAO,, NAO+ and E). The dynamical structure of each regime substantiates the statistical properties of the respective rainfall distribution and validates the clustering technique. The C regime is related to low-pressure systems over the North Atlantic that induce southwesterly and westerly moist winds over the country. The W regime is characterized by westerly disturbed weather associated with low-pressure systems mainly located over northern Europe. The NAO, regime is manifested by weak low-pressure systems near Portugal. The NAO+ regime corresponds to a well-developed Azores high with generally settled and dry weather conditions. Finally, the E regime is related to anomalous strong easterly winds and rather dry conditions. Although the variability in the frequencies of occurrence of the C and NAO, regimes is largely dominant in the interannual variability of the winter rainfall throughout Portugal, the C regime is particularly meaningful over northern Portugal and the NAO, regime acquires higher relevance over southern Portugal. The inclusion of the W regime improves the description of the variability over northern and central Portugal. Dry weather conditions prevail in both the NAO+ and E regimes, with hardly any exceptions. The occurrence of the NAO+ and the NAO, regimes is also strongly coupled with the North Atlantic oscillation. Copyright © 2005 Royal Meteorological Society [source] Age and growth, mortality, reproduction and relative yield per recruit of the bogue, Boops boops Linné, 1758 (Sparidae), from the Algarve (south of Portugal) longline fisheryJOURNAL OF APPLIED ICHTHYOLOGY, Issue 5 2006P. Monteiro Summary Samples of Boops boops ranging from 7.4 to 30.5 cm were obtained mainly by longline, supplemented by beach seining in the Ria Formosa lagoon, and by market sampling in the Algarve (southern Portugal). The macroscopic analyses of the gonads and the gonad somatic index showed that the south coast of Portugal B. boops spawn mainly from late winter to spring, between February and May. The length at first maturity was similar for males and females and the value for both sexes combined was estimated to be 15.22 cm, corresponding to an age range of 1,3. Age was determined by reading growth bands on otoliths. Age determination was validated by marginal increment analysis. The estimated parameters were L, = 28.06, K = 0.22 and t0 = ,1.42. Mortality rates were calculated for fish captured with longlines, and the estimated parameters were M = 0.33, Z = 1.04 and F = 0.71. Relative yield per recruit analysis and sensitivity analysis showed that the resource is moderately exploited. From the perspective of sustainability, these results provide support for the use of longlines as a gear that is among the least harmful for species such as the bogue. [source] Weight,length relationships for eight species of the family Triglidae discarded on the south coast of PortugalJOURNAL OF APPLIED ICHTHYOLOGY, Issue 4 2006S. Olim Summary Gurnards or triglids are medium-size marine bottom fishes that live in tropical and temperate seas. Four genera (Aspitrigla, Chelidonichthys, Lepidotrigla, Trigla) and eight species are found in the eastern Atlantic. In this study, we report the weight,length relationships for eight species, with 75 specimens of A. cuculus, 45 of C. obscurus, 84 C. gurnardus, 21 C. lucernus, 45 C. lastoviza, 550 L. cavillone, 255 L. dieuzeidei and 40 T. lyra. These triglids were caught by three different methods: crustacean trawl, fish trawl and purse seine off the Algarve coast; all specimens sampled were part of the discards. Samples were obtained from depths ranging between 20 and 540 m, during 27 trips and 86 hauls. To the best knowledge of the authors, this study presents the first reference on weight,length relationships for four fish species from the Algarve coast (southern Portugal). [source] Feeding habits of the gilthead seabream (Sparus aurata) from the Ria Formosa (southern Portugal) as compared to the black seabream (Spondyliosoma cantharus) and the annular seabream (Diplodus annularis)JOURNAL OF APPLIED ICHTHYOLOGY, Issue 2 2002C. Pita The feeding habits of Sparus aurata L., Diplodus annularis L. and Spondyliosoma cantharus L. in the Ria Formosa (southern Portugal) lagoon system were studied using three simple methods (frequency of occurrence, numeric percentage and percentage weight) and a composite index [index of relative importance (IRI)]. The Ivlev index was used to evaluate diet selectivity, while the Schoener overlap index was used to compare diets, and diet diversity was characterized by the Simpson index. The diets of the three species consist of a wide variety of food organisms, nevertheless S. aurata seems to be the most specialized. No significant dietary overlap was found, with S. aurata preferentially selecting gastropods and bivalves, while S. cantharus preferentially selected a wide variety of crustaceans and D. sargus a wider array, including crustaceans, gastropods and bivalves. [source] IS THERE AN ECOPHYSIOLOGICAL EXPLANATION FOR THE GAMETOPHYTE,TETRASPOROPHYTE RATIO IN GELIDIUM SESQUIPEDALE (RHODOPHYTA)?,JOURNAL OF PHYCOLOGY, Issue 2 2006Raquel Carmona In the fall, when 61% of the fronds of the Gelidium sesquipedale (Clem.) Born. et Thur. population located in Albufeira (southern Portugal) were reproductive, about 90% of these fronds were tetrasporophytes, whereas an equal percentage of female and male gametophytes was found (5%). The comparison of physiological performances of the reproductive phases (males, females and tetrasporophytes) did not reveal a physiological advantage of tetrasporic fronds. There were no significant differences either in the photosynthesis, nitrogen uptake, nitrate reductase activity, or biochemical composition of adult fronds. On the other hand, vegetative recruitment and spore production in the laboratory were significantly different. The re-attachment to calcareous substrate and the subsequent rhizoidal growth were faster in tetrasporophytes. Particular levels of temperature, rather than irradiance, had an important effect on the phase differences in the spore release, attachment, and germination rates. Significant results were the higher release of carpospores at all irradiances at 17°C, and the higher attachment percentage of carpospores at 13°C versus tetraspores. Under higher temperatures (21°C), tetraspores showed higher attachment rates while carpospores germinated more. G. sesquipedale cystocarps released carpospores for 2 months, while tetrasporangia stopped shedding tetraspores after 1 month, resulting in a 3-fold higher production of carpospores than tetraspores. Results showed that vegetative and spore recruitment may explain the low gametophyte,tetrasporophyte ratio of the studied population of G. sesquipedale as opposed to the physiological performance of phases. [source] Variation in the Sizes of Chthamalid Barnacle Post-Settlement Cyprids on European ShoresMARINE ECOLOGY, Issue 4 2001Ruth M. O'Riordan Abstract. As part of a wider study on the settlement and recruitment of Chthamalus spp. in Europe, this study investigated whether chthamalid cyprids can be separated by length on a European scale. Variation in cyprid length with latitude and temporal variation at selected localities were also examined. The lengths of cyprids collected between 1996,,,1999 on nine rocky shores in Europe are reported. Elminius modestus cyprids were found only at Roscoff, NW France and could be distinguished due to their carapace shape and length. They showed a unimodal length distribution, measuring between 450 and 625 µm, with no variation in length between the two sampling dates (1997 and 1998). Based on carapace shape and length, the remaining cyprids in the collections were identified as one of three chthamalid species, Chthamalus montagui, Chthamalus stellatus or Euraphia depressa. Bimodal length distributions of chthamalid cyprids were seen on some shores, while others had a single small-sized modal group (representing C. montagui on Atlantic shores and/or E. depressa in the Mediterranean) separated from a few distinctly larger cyprids (C. stellatus). Metamorphs collected simultaneously with cyprid collections were identified as C. stellatus or C. montagui, except at Roscoff, where E. modestus were also found. In southern Portugal, where all metamorphs collected were C. montagui and adult C. montagui were the dominant barnacles, most cyprids measured between 350 and 550 µm long and this size distribution coincides with the distribution expected for C. montagui. Cyprids collected on these four more southerly Portuguese shores had the same modal length class (475 µm) and this remained constant between successive years at Luz and Albufeira, Algarve. The smallest (350 µm long) wild chthamalid cyprids found were from southern Portugal and Italy. In Spain, France and Ireland the smallest chthamalid cyprid was 425 µm long. The results from the present study support the hypothesis that on Atlantic shores cyprids of C. montagui can be separated from those of C. stellatus based on size, although there is some variation in cyprid length with latitude as well as temporal variation at selected localities. [source] | |||||||||||||