35 resultados para REPRODUCTIVE ECOLOGY
Resumo:
Reproductive morphology of the Mediterranean red alga Kallymenia patens is described for the first time, confirming its position in the genus. K. patens is characterized by a non-procarpic female reproductive apparatus, carpogonial branch systems consisting of supporting cells bearing both three-celled carpogonial branches and subsidiary cells that lack a hypogynous cell and carpogonium; fusion cells develop numerous connecting filaments, and tetrasporangia are scattered over the thallus and are probably cruciately divided. Old fertile spathulate specimens of K. patens are morphologically similar to K. spathulata, but they can be distinguished by the length of spathulated proliferations (up to 0.6 cm and 6 cm, respectively), the length of inner cortical cells (up to 70 and 30 μm, respectively), and the gonimoblast location (in proliferations from the perennial part of the blade and over all the thallus surface, respectively)
Resumo:
Background:There is no actual evidence that the ART are directly related to the occurrence of weight discordance. In some studies, ART-‐conceived twin pregnancies are at greater risk than non-‐ART-‐conceived ones for pregnancy complications and adverse perinatal outcome: the incidences of pregnancy-‐induced hypertension, uterine bleeding, premature contractions, IUGR, fetal death, discordance, and cesarean section were significantly higher. Discordance rate was elevated (25.3% vs.17.0%) among ART twins, which can increase perinatal risk (increased incidence of SGA and NICU admission). Other studies say that perinatal and neonatal morbidity, gestational age at delivery, and birth weight are not affected by ART. Regarding the first trimester ultrasound, some studies didn’t notice significant differences in CRL disparity or birth weight discordance between spontaneous and ART-‐ conceived dichorionic twin pregnancies. In ART-‐conceived dichorionic twin pregnancies, CRL disparity may be associated with birth weight discordance. In some studies, CRL discordance in twin pregnancies in the first trimester was a frequent finding. Objectives: To analyze the association of the ART in the occurrence of weight discordance in the pregnancies between 2010 and 2013 in the Hospital Universitari de Girona Doctor Josep Trueta, and to describe the proportion of diagnosis of growth discordance in the first trimester by the ultrasonography technology. Methods: A retrospective cohort study will be performed in those patients with twin pregnancies between 2010 and 2013, within the Hospital Universitari de Girona Doctor Josep Trueta (HUJT). A retrospective and descriptive study will be done in those cases with discordance weight in the moment of the birth, in which the CRL will be studied in the first trimester ultrasound, describing the percentage of discordance detected in that moment. The general characteristics of the sample are going to be analyzed by Logistic RegressionInfluenceof
Resumo:
Background:There is no actual evidence that the ART are directly related to the occurrence of weight discordance. In some studies, ART-‐conceived twin pregnancies are at greater risk than non-‐ART-‐conceived ones for pregnancy complications and adverse perinatal outcome: the incidences of pregnancy-‐induced hypertension, uterine bleeding, premature contractions, IUGR, fetal death, discordance, and cesarean section were significantly higher. Discordance rate was elevated (25.3% vs.17.0%) among ART twins, which can increase perinatal risk (increased incidence of SGA and NICU admission). Other studies say that perinatal and neonatal morbidity, gestational age at delivery, and birth weight are not affected by ART. Regarding the first trimester ultrasound, some studies didn’t notice significant differences in CRL disparity or birth weight discordance between spontaneous and ART-‐ conceived dichorionic twin pregnancies. In ART-‐conceived dichorionic twin pregnancies, CRL disparity may be associated with birth weight discordance. In some studies, CRL discordance in twin pregnancies in the first trimester was a frequent finding. Objectives: To analyze the association of the ART in the occurrence of weight discordance in the pregnancies between 2010 and 2013 in the Hospital Universitari de Girona Doctor Josep Trueta, and to describe the proportion of diagnosis of growth discordance in the first trimester by the ultrasonography technology. Methods: A retrospective cohort study will be performed in those patients with twin pregnancies between 2010 and 2013, within the Hospital Universitari de Girona Doctor Josep Trueta (HUJT). A retrospective and descriptive study will be done in those cases with discordance weight in the moment of the birth, in which the CRL will be studied in the first trimester ultrasound, describing the percentage of discordance detected in that moment. The general characteristics of the sample are going to be analyzed by Logistic RegressionInfluenceof
Resumo:
The Ramon Margalez Prize in Ecology is awarded annually by the Goverment of Catalonia to recognize people who have distinghished themselves in the field of ecological science. Among the events that are held in connection with the award-giving ceremony, the University of Barcelona hosts a seminar by the awardee followed by a roundtable discussion.
Resumo:
Background:There is no actual evidence that the ART are directly related to the occurrence of weight discordance. In some studies, ART-‐conceived twin pregnancies are at greater risk than non-‐ART-‐conceived ones for pregnancy complications and adverse perinatal outcome: the incidences of pregnancy-‐induced hypertension, uterine bleeding, premature contractions, IUGR, fetal death, discordance, and cesarean section were significantly higher. Discordance rate was elevated (25.3% vs.17.0%) among ART twins, which can increase perinatal risk (increased incidence of SGA and NICU admission). Other studies say that perinatal and neonatal morbidity, gestational age at delivery, and birth weight are not affected by ART. Regarding the first trimester ultrasound, some studies didn’t notice significant differences in CRL disparity or birth weight discordance between spontaneous and ART-‐ conceived dichorionic twin pregnancies. In ART-‐conceived dichorionic twin pregnancies, CRL disparity may be associated with birth weight discordance. In some studies, CRL discordance in twin pregnancies in the first trimester was a frequent finding. Objectives: To analyze the association of the ART in the occurrence of weight discordance in the pregnancies between 2010 and 2013 in the Hospital Universitari de Girona Doctor Josep Trueta, and to describe the proportion of diagnosis of growth discordance in the first trimester by the ultrasonography technology. Methods: A retrospective cohort study will be performed in those patients with twin pregnancies between 2010 and 2013, within the Hospital Universitari de Girona Doctor Josep Trueta (HUJT). A retrospective and descriptive study will be done in those cases with discordance weight in the moment of the birth, in which the CRL will be studied in the first trimester ultrasound, describing the percentage of discordance detected in that moment. The general characteristics of the sample are going to be analyzed by Logistic RegressionInfluenceof
Resumo:
We describe the distribution and the ecology of three Armillaria species observed in silver fir (Abies alba) forests of the Pyrenees. We surveyed the presence and abundance of Armillaria above and belowground in 29 stands. Isolates were identified by the PCR-RFLP pattern of the IGS-1 region of their ribosomal DNA. We measured several ecological and management parameters of each stand in order to describe Armillaria infected sites. Armillaria cepistipes was the most abundant of three species observed. Armillaria gallica was dominant in soils with a higher pH and at lower elevations. Armillaria ostoyae seemed to be more frequent in stands where A. alba recently increased its dominance relative to other forest tree species. Thinning activities correlated with an increased abundance of Armillaria belowground. In 83% of the stands the same Armillaria species was observed above and belowground. It seems that in a conifer forest, A. cepistipes can be more frequent than A. ostoyae, a virulent conifer pathogen. Since logging is related to a higher abundance of Armillaria in the soil, the particular Armillaria species present in a given stand could be considered an additional site factor when making management decisions.
Resumo:
Inter-individual diet variation within populations is likely to have important ecological and evolutionary implications. The diet-fitness relationships at the individual level and the emerging population processes are, however, poorly understood for most avian predators inhabiting complex terrestrial ecosystems. In this study, we use an isotopic approach to assess the trophic ecology of nestlings in a long-lived raptor, the Bonelli"s eagle Aquila fasciata, and investigate whether nestling dietary breath and main prey consumption can affect the species" reproductive performance at two spatial scales: territories within populations and populations over a large geographic area. At the territory level, those breeding pairs whose nestlings consumed similar diets to the overall population (i.e. moderate consumption of preferred prey, but complemented by alternative prey categories) or those disproportionally consuming preferred prey were more likely to fledge two chicks. An increase in the diet diversity, however, related negatively with productivity. The age and replacements of breeding pair members had also an influence on productivity, with more fledglings associated to adult pairs with few replacements, as expected in long-lived species. At the population level, mean productivity was higher in those population-years with lower dietary breadth and higher diet similarity among territories, which was related to an overall higher consumption of preferred prey. Thus, we revealed a correspondence in diet-fitness relationships at two spatial scales: territories and populations. We suggest that stable isotope analyses may be a powerful tool to monitor the diet of terrestrial avian predators on large spatio-temporal scales, which could serve to detect potential changes in the availability of those prey on which predators depend for breeding. We encourage ecologists and evolutionary and conservation biologists concerned with the multi-scale fitness consequences of inter-individual variation in resource use to employ similar stable isotope-based approaches, which can be successfully applied to complex ecosystems such as the Mediterranean.
Resumo:
Major oil spills can have long-term impacts since oil pollution does not only result in acute mortality of marine organisms, but also affects productivity levels, predator-prey dynamics, and damages habitats that support marine communities. However, despite the conservation implications of oil accidents, the monitoring and assessment of its lasting impacts still remains a difficult and daunting task. Here, we used European shags to evaluate the overall, lasting effects of the Prestige oil spill (2002) on the affected marine ecosystem. Using δ15N and Hg analysis, we trace temporal changes in feeding ecology potentially related to alterations of the food web due to the spill. Using climatic and oceanic data, we also investigate the influence of North Atlantic Oscillation (NAO) index, the sea surface temperature (SST) and the chlorophyll a (Chl a) on the observed changes. Analysis of δ15N and Hg concentrations revealed that after the Prestige oil spill, shag chicks abruptly switched their trophic level from a diet based on a high percentage of demersal-benthic fish to a higher proportion of pelagic/semi-pelagic species. There was no evidence that Chl a, SST and NAO reflected any particular changes or severity in environmental conditions for any year or season that may explain the sudden change observed in trophic level. Thus, this study highlighted an impact on the marine food web for at least three years. Our results provide the best evidence to date of the long-term consequences of the Prestige oil spill. They also show how, regardless of wider oceanographic variability, lasting impacts on predator-prey dynamics can be assessed using biochemical markers. This is particularly useful if larger scale and longer term monitoring of all trophic levels is unfeasible due to limited funding or high ecosystem complexity.
Resumo:
This paper presents a detailed description of the reproductive characters of Mediterranean Seirospora giraudyi based on fresh material collected in the northwestern coast of Spain. Vegetative cells are uninucleate. The plant is monoecious. Spermantangial parent’s cells are clustered on modified dwarf determinate filaments, usually situated on adaxial surfaces of branches. One to four spermatia are formed by elongation and proximal divisions of the spermatangial parent cells. Spermatium with a nucleus situated ina mec. The thallus is procarpic. The four-celled carpogonial branch is initially L-shaped, and it is situated on a periaxial supporting fertile axial cell. The mature carpogonial branch is U-shaped and the supporting cell and second periaxial cell enlarge and divide transversely to reproduce a pair uninicleate auxiliary cell. The nucleus in the ferlilized carpogonium divides twice and the carpogonium cleaves vertically into two cells that, turn, cut off a pair of uninucleate connecting cells that fuse with the auxiliary cells on opposite sides; the diploid nuclei in the connecting cells divide at the site of fusion and one of the nuclei enters the auxiliary cell white the other is extruded. Each auxiliary cell gives to a terminal primary gonimolobe initials. Gonimolobes form lax chains of carposporangia. As the gonimoblasts mature, both lobes of the foot cell which is situated on the supporting cell elongate the upper one secondary connecting with the supporting cell, and the lower one with the fertile axial cell. The gonimoblasts are subtended at maturity by one to several clusters of involucral flaments. Seirospora is currently placed in the tribe Euptiloteae; however the reproductive character of S.giraudyi is dentical to those described for the Cañllithamnieae. Molecular studies are needed to confirm the taxonomic position of S.giraudyi as well as that of the other species placed Seirospora
Resumo:
We studied the reproductive cycle of the sea urchin Arbacia lixula in a subtidal population from northeast Spain over four years using a gonadosomatic index (GSI) and gonad histology. Our results show that the GSI of A. lixula follows a seasonal cycle which peaks in May-July and attains its lowest values in October-November every year. The time course of the GSI matched closely the photoperiod cycle. We also found a remarkable inter-annual variability in the maximum value of GSI, which correlated with mean water temperature during the gonad growth period (winter and spring). Gonad histology was also in agreement with a single gametogenic cycle per year in this species. We explored the application of circular statistics to present and analyse gonadal development data, which allowed us to adequately handle the high intra-individual variability detected, with several developmental stages commonly found within the same gonad. The picture that emerged is one of a gametogenic timing driven by photoperiod, while the amount of reproductive output is determined by temperature. This is coherent with the tropical origin of the species and lends support to recent warnings about an increase in the abundance of this species in the Mediterranean as a result of global warming, with associated increased impact potential in sublittoral communities.
Resumo:
[cat] Utilitzem un conjunt de mètriques del paisatge per estudiar l'evolució a llarg termini seguida en una típica zona costanera del Mediterrani des de 1850 fins a 2005, que mostren una greu deterioració del medi ambient entre 1950 i 2005. Les principals forces motores d'aquesta degradació del paisatge han estat el creixement urbà experimentat a les antigues zones agrícoles situades a les planes litorals, juntament amb l'abandonament i la reforestació dels vessants dels pujols interceptats per àrees residencials de baixa densitat, carreteres i altres infraestructures lineals. Duem a terme una anàlisi estadística de redundància (RDA) amb la finalitat d'identificar els que considerem com alguns agents rectors socioeconòmics i polítics d'última instància d'aquests impactes ambientals. Els resultats confirmen les nostres hipòtesis interpretatives, que són que: 1) els canvis en les cobertes i usos del sòl determinen canvis en les propietats dels paisatge, tant estructurals com funcionals; 2) aquests canvis no es produeixen per atzar, sinó que estan relacionats amb factors geogràfics i forces socioeconòmiques i polítiques.
Resumo:
[cat] Utilitzem un conjunt de mètriques del paisatge per estudiar l'evolució a llarg termini seguida en una típica zona costanera del Mediterrani des de 1850 fins a 2005, que mostren una greu deterioració del medi ambient entre 1950 i 2005. Les principals forces motores d'aquesta degradació del paisatge han estat el creixement urbà experimentat a les antigues zones agrícoles situades a les planes litorals, juntament amb l'abandonament i la reforestació dels vessants dels pujols interceptats per àrees residencials de baixa densitat, carreteres i altres infraestructures lineals. Duem a terme una anàlisi estadística de redundància (RDA) amb la finalitat d'identificar els que considerem com alguns agents rectors socioeconòmics i polítics d'última instància d'aquests impactes ambientals. Els resultats confirmen les nostres hipòtesis interpretatives, que són que: 1) els canvis en les cobertes i usos del sòl determinen canvis en les propietats dels paisatge, tant estructurals com funcionals; 2) aquests canvis no es produeixen per atzar, sinó que estan relacionats amb factors geogràfics i forces socioeconòmiques i polítiques.
Resumo:
In the past f ew years numerous authors have examined how the current economic crisis in Spain has dif f erential impacts on women and men.1 While this is important to show, this article’s goal is to make the leap f rom a mere description of the gendered effects of the crisis, to an analysis of some of the very gendered processes that shape it at its core. In other words, the intent is to understand how both the crisis itself and the ways the state manages it are structurally shaped by gender.
Resumo:
The reproductive biology of the Mediterranean Snake cel, Ophichthus Rufus (Ophichthidae), was studied on the basis of microscopic and macroscopic analysis. Results show that O.rufus is an oviparous species with a group synchronous ovary type. The maturation process of the gonads starts in December and progress until August, when ovulation and a pawing take place. It is a fractional spawned with buoyant eggs. Potential annual fecundity estimates ranged from 1426 to 23.605 oocytes. Except for small sizes, a clear predominance of females was observed
Resumo:
Trophic ecology and movements are critical issues for understanding the role of marine predators in food webs and for facing the challenges of their conservation. Seabird foraging ecology has been increasingly studied, but small elusive species, such as those forming the"little shearwater" complex, remain poorly known. We present the first study on the movements and feeding ecology of the Barolo shearwater Puffinus baroli baroli in a colony from the Azores archipelago (NE Atlantic), combining global location-sensing units, stable isotope analyses of feathers (δ13C and δ15N), stomach flushings and data from maximum depth gauges. During the chick-rearing period, parents visited their nests most nights, foraged mainly south of the colony and fed at lower trophic levels than during the non-breeding period. Squid was the most diverse prey (6 families and at least 10 different taxa), but species composition varied considerably between years. Two squid families, Onychoteuthidae and Argonautidae, and the fish family Phycidae accounted for 82.3% of ingested prey by number. On average, maximum dive depths per foraging trip reached 14.8 m (range: 7.9 to 23.1 m). After the breeding period, birds dispersed offshore in all directions and up to 2500 km from the breeding colony, and fed at higher trophic levels. Overall, our results indicate that the Barolo shearwater is a non-migratory shearwater feeding at the lowest trophic level among Macaronesian seabirds, showing both diurnal and nocturnal activity and feeding deeper in the water column, principally on small schooling squid and fish. These traits contrast with those of 3 other Azorean Procellariiformes (Cory"s shearwater Calonectris diomedea, the Madeiran storm-petrel Oceanodroma castro and Monteiro"s storm-petrel O. monteiroi), indicating ecological segregation within the Azorean seabird community.