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41.
Brazil hosts the largest expanse of tropical ecosystems within protected areas (PAs), which shelter biodiversity and support traditional human populations. We assessed the vulnerability to climate change of 993 terrestrial and coastal-marine Brazilian PAs by combining indicators of climatic-change hazard with indicators of PA resilience (size, native vegetation cover, and probability of climate-driven vegetation transition). This combination of indicators allows the identification of broad climate-change adaptation pathways. Seventeen PAs (20,611 km2) were highly vulnerable and located mainly in the Atlantic Forest (7 PAs), Cerrado (6), and the Amazon (4). Two hundred fifty-eight PAs (756,569 km2), located primarily in Amazonia, had a medium vulnerability. In the Amazon and western Cerrado, the projected severe climatic change and probability of climate-driven vegetation transition drove vulnerability up, despite the generally good conservation status of PAs. Over 80% of PAs of high or moderate vulnerability are managed by indigenous populations. Hence, besides the potential risks to biodiversity, the traditional knowledge and livelihoods of the people inhabiting these PAs may be threatened. In at least 870 PAs, primarily in the Atlantic Forest and Amazon, adaptation could happen with little or no intervention due to low climate-change hazard, high resilience status, or both. At least 20 PAs in the Atlantic Forest, Cerrado, and Amazonia should be targeted for stronger interventions (e.g., improvement of ecological connectivity), given their low resilience status. Despite being a first attempt to link vulnerability and adaptation in Brazilian PAs, we suggest that some of the PAs identified as highly or moderately vulnerable should be prioritized for testing potential adaptation strategies in the near future.  相似文献   
42.
ABSTRACT

Deforestation driven by agricultural expansion is a major threat to the biodiversity of the Amazon Basin. Modelling how deforestation responds to environmental policy implementation has thus become a policy relevant scientific undertaking. However, empirical parameterization of land-use/cover change (LUCC) models is challenging due to the high complexity and uncertainty of land-use decisions. Bayesian Network (BN) modelling provides an effective framework to integrate various data sources including expert knowledge. In this study, we integrate remote sensing products with data from farm-household surveys and a decision game to model LUCC at the BR-163, in Brazil. Our ‘business as usual’ scenario indicates cumulative forest cover loss in the study region of 8,000 km2 between 2014 and 2030, whereas ‘intensified law-enforcement’ would reduce cumulative deforestation to 1,600 km2 over the same time interval. Our findings underline the importance of conservation law enforcement in modulating the impact of agricultural market incentives on land cover change.  相似文献   
43.
Drinking of arsenic (As)-contaminated groundwater has adverse effects on health of millions of people worldwide. This study aimed to determine the degree of severity of As exposure from drinking water in peri-urban Moyna and Ardebok villages, West Bengal, India. Arsenic concentrations in hair, nail and urine samp les of the individuals were determined. Arsenical dermatosis, keratosis and melanosis were investigated through medical evaluation. We have evaluated the association between As exposure from drinking water, and keratosis and melanosis outcomes. The results showed that 82.7?% of the sampled tube wells contain As concentrations above 10?μg/L, while 57.7?% contain As concentrations above 50?μg/L. The hair, nail and urine As concentrations were positively correlated with As concentrations in drinking water. In our study population, we observed a strong association between As concentrations ranging 51-99?μg/L and keratosis and melanosis outcomes, although the probability decreases at higher concentration ranges perhaps due to switching away from the use of As-contaminated tube wells for drinking and cooking purposes. High As concentrations in hair, nail and urine were observed to be associated with the age of the study population. The level of As concentrations in hair, nail and urine samples of the study population indicated the degree of severity of As exposure in the study region.  相似文献   
44.
Several lines of evidence indicate that aggregations of yellowfin tuna associated with floating objects are more frequently composed of small animals than larger ones. Also, the diet of small yellowfin tuna caught at anchored fish aggregating devices (FADs) around Oahu, Hawaii, was found to shift quite rapidly when these fish reached approximately 50 cm FL. In order to test for ontogenetic changes in aggregation behavior, we tagged and released two distinct size classes of yellowfin tuna in an array of anchored FADs around Oahu, Hawaii. Twenty-four yellowfin tuna 30–39 cm FL and 16 yellowfin tuna 63–83 cm FL were tagged with acoustic transmitters and released near anchored FADs equipped with automated acoustic receivers. Fish in the smaller size class stayed about 2.5 times longer at individual FADs than the larger fish (mean 4.05 days vs. 1.65 days) and displayed larger horizontal movements within the array. However, the durations of unassociated phases, residence times in the entire FAD array, percentage of time spent associated with FADs and numbers of movements between FADs did not show any difference between the two size groups. The observed size-dependent behavior is discussed in terms of physiological abilities, diet segregation and anti-predator behavior.  相似文献   
45.
Radon-222 activity concentration has been monitored since 1999 in an underground limestone quarry located in Vincennes, near Paris, France. It is homogeneous in summer, with an average value of 1700 Bq m(-3), and varies from 730 to 1450 Bq m(-3) in winter, indicating natural ventilation with a rate ranging from 0.5 to 2.4 x 10(-6) s(-1) (0.04-0.22 day(-1)). This hypothesis is supported by measurements in the vertical access pit where, in winter, a turbulent air current produces a stable radon profile, smoothly decreasing from 700 Bq m(-3) at 20 m depth to 300 Bq m(-3) at surface. In summer, a thermal stratification is maintained in the pit, but the radon-222 concentration jumps repeatedly between 100 and 2000 Bq m(-3). These jumps are due to atmospheric pressure pumping, which induces ventilation in the quarry at a rate of about 0.1 x 10(-6) s(-1) (0.009 day(-1)). Radon-222 monitoring thus provides a dynamical characterisation of ventilation regimes, which is important for the assessment of the long-term evolution of underground systems.  相似文献   
46.
A huge tension exists between recognizing sustainable development (SD) as a meta-discourse and accepting a limitless interpretational width. We analyse the impacts of diversity of worldviews on the interpretation of SD—as a knowledge-based concept—through a critical literature review, resulting in recommendations on the topic. We apply a social-constructionist approach, appreciating the complex socio-ecological interactions at the heart of SD. Only recently worldviews are recognized as constitutive elements of SD. Little attention has been given to the impacts on generated knowledge for SD. Variety of worldviews induces a variety of knowledge claims and needs. To retain SD’s ‘universal’ appeal as practical decision-guiding strategy for policy and action, we propose an integrative approach towards knowledge for SD—entailing an explicit pluralization of knowledge. SD should be re-interpreted as a joint worldviews construct, embracing a diversity of views in collaborative research and co-production of knowledge. Interpreting SD as a joint endeavour is necessary to overcome historical obstacles like cultural hegemony and a hierarchy of knowledge systems. We identified the following requirements for an inclusive knowledge for SD paradigm: re-interpretation of SD as a worldview constructs in progress; interpretative flexibility; co-production of knowledge; subjectivity awareness and self-reflexivity; respect for a diversity of worldviews/knowledges; identifying shared goals; collaborative research; a systems approach; transdisciplinarity; and recognition of contextuality. Further research—concerning potential methodologies and typologies—to reconcile variety of worldviews and knowledge systems in a joint SD worldviews construct is urgently needed.  相似文献   
47.
Coastal populations of small pelagic fish display nested aggregation levels. Above the level of the school structure, clusters are observed the nature of which has not been definitively determined. We hypothesized that these clusters corresponded to a materialisation of the microcohorts originating from successive spawnings of fish populations in their vital domain.A candidate individual-based model was developed to investigate this hypothesis. This model is based on pattern-oriented modelling of a concrete documented case: the dynamics of the round sardinella (Sardinella aurita) population living off the West African coasts and subject to environmental fluctuations caused by seasonal upwelling. The simulated agents were round sardinella microcohorts situated and moving in a discretised physical environment. The combined effects of environmental forcing (temperature, wind, retention) and inner biological dynamics (reproduction, growth and mortality, competition) condition the dynamics of this population.The modelled behaviour generated realistic dynamic patterns (population distribution, spawning zones, periods and plasticity, biomass fluctuations), which were obtained simultaneously and successfully compared with observations. The steady-state number of microcohorts obtained after simulation convergence was similar to the number of clusters observed in situ in this area for this population.The realism and diversity of the patterns simultaneously simulated suggested the cluster-microcohort equivalence hypothesis as a candidate framework accounting for the origin of the clusters observed in situ. Within this preliminary exploration, we discuss the consistency of the hypothesis and the accuracy of the model. If the correspondence between clusters and microcohorts proves to be real, it may be transient and progressively modified by other environmental factors. If stable over time, as simulated in the model, the number of observed clusters should be related to the number of spawning events in the species’ lifetime.  相似文献   
48.
Development along the western beachfront of Port Alfred, which is situated along a sandy shoreline, increased markedly in the 1960s as the coastal town became a popular holiday resort. This development included the removal of coastal vegetation, which resulted in the destabilization of dunes and migration of sand westerly onto the road, West Beach parking lot, and lawns of the cabanas. Sand traps were constructed to collect sand blowing across the dunes over set periods, and the net sand movement along the mobile dune belt was calculated using Hunter's equation. The dunes show an easterly movement of sand at a rate of 3.5 m/yr, which is comparable with figures recorded along other areas of this coastline. Considering the wind regime and amount of sand movement along this coast, it is inappropriate to clear vegetation and develop within the dune region.  相似文献   
49.
50.
Summary The ripe fruit of the Indian mulberry,Morinda citrifolia, is the host plant forDrosophila sechellia but is highly toxic for three closely related species (D. melanogaster, D. simulans, D. mauritiana). A simple bioassay is described with which a clear dose response to the fruit was found for these species. Significant differences in reactivity to the ripe fruit were found among species. Tested strains ofD. simulans andD. mauritiana adults were more sensitive to the toxic properties of the fruit thanD. melanogaster. A marked intraspecific variability was shown inD. melanogaster. Reciprocal interspecific hybridizations betweenD. sechellia andD. mauritiana suggested an autosomal dominant control of resistance. MoreoverD. melanogaster intraspecific crossings suggested the influence of an additional X-linked factor. Responses of flies toMorinda fruit in different states were tested in a T olfactometer. The less resistant strains ofDrosophila generally showed less preference for the ripe fruit.  相似文献   
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