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101.
The persistence of narrowly adapted species under climate change will depend on their ability to migrate apace with their historical climatic envelope or to adapt in place to maintain fitness. This second path to persistence can only occur if there is sufficient genetic variance for response to new selection regimes. Inadequate levels of genetic variation can be remedied through assisted gene flow (AGF), that is the intentional introduction of individuals genetically adapted to localities with historic climates similar to the current or future climate experienced by the resident population. However, the timing of reproduction is frequently adapted to local conditions. Phenological mismatch between residents and migrants can reduce resident × migrant mating frequencies, slowing the introgression of migrant alleles into the resident genetic background and impeding evolutionary rescue efforts. Focusing on plants, we devised a method to estimate the frequency of resident × migrant matings based on flowering schedules and applied it in an experiment that mimicked the first generation of an AGF program with Chamaecrista fasciculata, a prairie annual, under current and expected future temperature regimes. Phenological mismatch reduced the potential for resident × migrant matings by 40–90%, regardless of thermal treatment. The most successful migrant sires were the most resident like in their flowering time, further biasing the genetic admixture between resident and migrant populations. Other loci contributing to local adaptation—heat‐tolerance genes, for instance—may be in linkage disequilibrium with phenology when residents and migrants are combined into a single mating pool. Thus, introgression of potentially adaptive migrant alleles into the resident genetic background is slowed when selection acts against migrant phenology. Successful AGF programs may require sustained high immigration rates or preliminary breeding programs when phenologically matched migrant source populations are unavailable. 相似文献
102.
Aquaculture studies have revealed that polyunsaturated fatty acids are critical for maintaining substantial growth, survival
and reproductive rates, and high food conversion efficiencies for a wide variety of marine and freshwater organisms. The aim
of this study was to investigate the gross biochemical and fatty acid composition of both neutral and polar lipid compartments
of the razor clam Solen marginatus throughout embryonic and larval development. High levels of stored reserves in S. marginatus eggs allow a short larval development, lasting only 8 days. The energy required for embryogenesis was obtained from stored
proteins. During larval development from D-shaped veliger until settlement, protein, lipid, and carbohydrate reserves were
indistinctly stored for metamorphosis. Although total lipids increased, fatty acids in both neutral and polar lipids decreased
during embryonic development. The depots allow a short larval development in which settlement is reached with lower amounts
of stored neutral and polar lipids than the contents found in the oocytes. Non-methylene-interrupted dienoic fatty acid levels
were similar to those of some polyunsaturated fatty acids, with increasing percentages at the onset of metamorphosis. This
study indicates that S. marginatus exhibits a different pattern in the use of gross biochemical and fatty acid reserves during larval development compared to
other razor clam and bivalve species, mainly due to the large size of its eggs and the short larval development stage reported
in this species. 相似文献
103.
Santos JA Galante-Oliveira S Barroso C 《Journal of environmental monitoring : JEM》2011,13(3):673-680
The current work presents an innovative statistical approach to model ordinal variables in environmental monitoring studies. An ordinal variable has values that can only be compared as "less", "equal" or "greater" and it is not possible to have information about the size of the difference between two particular values. The example of ordinal variable under this study is the vas deferens sequence (VDS) used in imposex (superimposition of male sexual characters onto prosobranch females) field assessment programmes for monitoring tributyltin (TBT) pollution. The statistical methodology presented here is the ordered logit regression model. It assumes that the VDS is an ordinal variable whose values match up a process of imposex development that can be considered continuous in both biological and statistical senses and can be described by a latent non-observable continuous variable. This model was applied to the case study of Nucella lapillus imposex monitoring surveys conducted in the Portuguese coast between 2003 and 2008 to evaluate the temporal evolution of TBT pollution in this country. In order to produce more reliable conclusions, the proposed model includes covariates that may influence the imposex response besides TBT (e.g. the shell size). The model also provides an analysis of the environmental risk associated to TBT pollution by estimating the probability of the occurrence of females with VDS ≥ 2 in each year, according to OSPAR criteria. We consider that the proposed application of this statistical methodology has a great potential in environmental monitoring whenever there is the need to model variables that can only be assessed through an ordinal scale of values. 相似文献
104.
Adriana Pajares Guillermo Stettler Jose Gianotti Silvia Bustos Susana Criado Norman A. García 《毒物与环境化学》2013,95(1-4):115-124
A kinetic study of the RB‐sensitized photooxygenation of a series of chlorohydroxyaromatic (ClArOH) water contaminants (phenolic and dihydroxybenzene derivatives) has been carried out. In addition, an exhaustive study on the possible interactions of RB electronically excited triplet and singlet states with ClArOH was also developed. The determination of relative rates of oxygen uptake upon sensitized irradiation, employing auxiliar selective quenchers of oxygen active species, indicate the contribution of both singlet molecular oxygen (ca. 71%) and Superoxide ion (ca. 26%) as the reactive pathways for ClArOH degradation. The substitution by chlorine atoms in position meta greatly decrease the photooxygenation rate of the phenolic derivatives. For the dihydroxybenzene series, increase in nuclear chlorination parallels a decrease in the photodegradation rate. Outdoors sensitized solar irradiation experiments on different ClArOH mixtures leads to measurable levels of oxygen after a few minutes exposure. From the environmental point of view, and ruling out the possibility of direct‐irradiation photoreactions, sensitized photooxygenation appears as an alternative pathway for ClArOH degradation, in competence with other naturally‐occurring photoprocesses involving reactive transient species. 相似文献
105.
Diane Ciaparra Eric Aries Marie-Jo Booth David R. Anderson Susana Marta Almeida Stuart Harrad 《Atmospheric environment (Oxford, England : 1994)》2009,43(12):2070-2079
Investigations have been undertaken at two integrated steelworks in the UK to characterise airborne organic micro-pollutants and to assess the contribution of iron ore sintering and coke making operations on the air quality. Concentrations of volatile organic compounds (VOCs), namely benzene, toluene and p-xylene, were measured continuously within the boundary of a coking plant using for the first time differential optical absorption spectrometry (DOAS) between 2004 and 2006. Concentrations were obtained along two monitoring paths surrounding the coke plant and the average benzene concentration measured along both paths over the campaign was 28 μg m?3. Highest benzene concentrations were associated with winds downwind of the coke oven batteries. Concentrations of polycyclic aromatic hydrocarbons (PAHs) in ambient air were measured during 27 consecutive days in 2005 at three different locations on an integrated steelworks. PAH profiles were determined for each sampling point and compared to coke oven and sinter plant emission profiles showing an impact from the steelworks. The mean benzo [a] pyrene concentration determined in the immediate vicinity of the coke ovens downwind from the battery was 19 ng m?3, whereas for the two other sites average benzo [a] pyrene concentrations were much lower (around 1 ng m?3). Data were analysed using principal components analysis (PCA) and results showed that coke making and iron ore sintering were responsible for most of the variation in the PAH concentrations in the vicinity of the investigated plant. 相似文献
106.
Malcolm Richard Gent Mario Menendez Javier Toraño Diego Isidro Susana Torno 《Waste management (New York, N.Y.)》2009,29(6):1819-1827
Cylindrical cyclone media separators using a suspended calcite separation media simulating industrial scale operations are demonstrated to effectively separate a wide variety of forms and a greater range of particle sizes of plastics by density than presently recycled. Purities of plastic products and recoveries obtained from mixed plastic wastes are comparable to those reported for established separations. Products of ≈100% purity with recoveries of >99% were obtained for high density fractions and >98% purities and recoveries for the low density fractions. Cyclonic centrifugal forces and/or the fine particle size of the separation media appear to minimize hydroscopic and particle shape effects.A mathematical model is proposed for defining plastic waste feed rates and treatable particle size ranges for the LARCODEMS media separator.Waste plastic separations yielded Ecart probable (Ep) values ?0.024 for a water only separation media. The Ep for 1.1 g cm?3 separation medias was <0.032 with minimal to no variation in values for 1–8 mm particle sizes. Variation in the quality of separations is shown to be minimal with <72 μm, <45 μm and <2 μm media particle sizes. Media density offset created varied according to particle size. 相似文献
107.
Sebastián Villasante David Rodríguez-González Manel Antelo Susana Rivero-Rodríguez José A. de Santiago Gonzalo Macho 《Ambio》2013,42(8):923-936
In this paper we examine the effect of Gross Domestic Product (GDP) on the level of fish intake in China in comparison with the rest of the world. We also analyse the origin and destination of China’s seafood products in order to understand the main patterns during the last decades. The results show that in the 1961–2011 period the rate of growth of the GDP in China doubled that of other developing regions, while the daily fish intake of China increased fourfold, making China the largest fish consumer in the world. Given the size and scale of China’s role in production, consumption, and global transformation of seafood markets, China is shaping a new era of industrialization in the history of the fishing industry. 相似文献
108.
Joël Meunier Susana Figueiredo Pinto Reto Burri Alexandre Roulin 《Behavioral ecology and sociobiology》2011,65(4):559-567
Although melanin is the most common pigment in animal integuments, the adaptive function of variation in melanin-based coloration
remains poorly understood. The individual fitness returns associated with melanin pigments can be variable across species
as these pigments can have physical and biological protective properties and genes involved in melanogenesis may vary in the
intensity of pleiotropic effects. Moreover, dark and pale coloration can also enhance camouflage in alternative habitats and
melanin-based coloration can be involved in social interactions. We investigated whether darker or paler individuals achieve
a higher fitness in birds, a taxon wherein associations between melanin-based coloration and fitness parameters have been
studied in a large number of species. A meta-analysis showed that the degree of melanin-based coloration was not significantly
associated with laying date, clutch size, brood size, and survival across 26 species. Similar results were found when restricting
the analyses to non-sexually dimorphic birds, colour polymorphic and monomorphic species, in passerines and non-passerines
and in species for which inter-individual variation in melanism is due to colour intensity. However, eumelanic coloration
was positively associated with clutch and brood size in sexually dimorphic species and those that vary in the size of black
patches, respectively. Given that greater extent of melanin-based coloration was positively associated with reproductive parameters
and survival in some species but negatively in other species, we conclude that in birds the sign and magnitude of selection
exerted on melanin-based coloration is species- or trait-specific. 相似文献
109.
Griselda V. Garaffo Silvana L. Dans Susana N. Pedraza Enrique A. Crespo Mariana Degrati 《Marine Biology》2007,152(1):165-177
Off Patagonian coasts, Argentina, the dusky dolphin is one of the most common small cetaceans. This species is the aim of
newly developed watching activities during summer in Golfo Nuevo. However, the real occurrence and movement pattern are unknown.
The objectives of this work were to investigate the predictability of dusky dolphin distribution, group structure and behaviour
in the western portion of Golfo Nuevo, with respect to environmental features (bottom depth, bottom slope, distance from shore
and substrate). Random transects in the bay were searched by small boat during the summer and autumn of 2001–2004. When a
group of dolphins was sighted, estimates of group size, composition (mothers with calves, adults and juveniles only, and mixed
groups) and the predominant activity (feeding, travelling, socialising, resting and milling) were recorded and thereafter at 2 min intervals. A grid of 1.5 × 1.5 km was constructed and each cell was characterised
by environmental features, Area Use Index (percent of total annual search effort) and Activity Index (predominant behaviour
of groups observed in that cell). Mothers with calves and smaller groups and resting behaviour occurred in shallowest waters supporting the idea/hypothesis that movement to shallower water is related to increased
safety for individuals. Travelling occurred in the deepest areas with other behaviours observed in intermediate depths. Dolphin distribution within the bay
differed significantly between years, but this was not related to any of the factors analysed in this study. Although there
was considerable variation between years, in general, dolphins were found in deeper waters further from shore (except for
mother–calf groups) and over areas with steeper seafloor gradient. The high variability in the distribution of the animals
does not allow for the generation of a simple, area-specific management plan. 相似文献
110.
Community Renewable Energy (CRE) has been defying conventional energy systems for decades, though only recently it started to feature in academic and institutional discourses. Despite its new appeal, the literature on the impacts and factors influencing CRE projects is still scarce and builds mostly on studies in Europe and North America. In developing countries, where electricity access is low and energy poverty is prevalent, CRE can offer interesting opportunities for rural electrification and added benefits. The objective of this study is to assess the impacts of community-owned renewable energy projects and identify the internal and external drivers and barriers to their success. An exploratory case-study approach was used for collecting data, through interviews and observations, in two community micro-hydro projects in Indonesia. The results showed positive socio-economic impacts that exceed electrification benefits, and the reported success of community energy projects can be traced back to a combination of community-level as well as external factors. Yet, particularly important is the role of the intermediary organisation (Ibeka) in building communities’ ownership, enhancing (technical, entrepreneurial and managerial) capacities, transferring knowledge and technology, establishing innovative financing models and shaping policy. Such organisations are critical in bridging external and internal factors and thus represent a key element in integrating the proposed analytical frameworks. 相似文献