Dispersal attempts can be costly and may often end in failure. Individuals should therefore only disperse when the benefits
of dispersal outweigh the costs. While previous research has focussed on aspects of the individual that may affect dispersal
success, social factors may also influence dispersal outcomes. One way of achieving successful dispersal could be through
cooperative, or coalition dispersal. I investigated this possibility in the cooperatively breeding Arabian babbler Turdoides squamiceps. I found that coalition dispersal appears to be an effective strategy to ensure the success of dispersal attempts, with coalitions
more successful than lone individuals at taking over the breeding position in a new group. Lone dispersal was more costly
than coalition dispersal, with lone individuals suffering a greater loss of body mass during dispersal attempts. These results
suggest a substantial short-term benefit for this type of cooperative behaviour. There was no evidence for dispersal polymorphism
in the population, with no detectable phenotypic difference between dispersers and non-dispersers or those that dispersed
as part of a coalition compared with those that dispersed alone. 相似文献
Journal of Polymers and the Environment - Sophorolipids are glycolipid biosurfactants produced by the yeast Starmerella bombicola. They have great potential for application in the food industry due... 相似文献
The adjustment to deal with intragroup food competition is probably the most plausible explanation of high levels of fission–fusion
dynamics. However, studies did not always support expected relations between food availability, ranging costs, and subgroup
size. We used several levels of analysis differing in the time and spatial scale in order to investigate this explanation
in spider monkeys. In our study, subgroups were larger when food availability was higher across most levels of analyses used.
We also found a fine-scale adjustment: compared to the food patch previously visited, spider monkeys traveled to larger patches
just after fusions. This was not without an immediate travel cost: the interpatch distance and travel time after a fusion
were longer than that before the fusion. This rapid adjustment shows the flexibility that fission–fusion dynamics can offer.
Spider monkeys are in large subgroups only when food conditions are favorable, as evidenced by the fact that at all the other
time-scale levels larger subgroups did not experience greater ranging costs than smaller subgroups. Our results indicate that
on the whole spider monkeys successfully minimize ranging costs by fission and fusion of subgroups. 相似文献
Systematic conservation planning is intended to inform spatially explicit decision making. Doing so requires that it be integrated into complex regulatory and governance processes, and there are limited instances where this has been achieved effectively. South Africa is a global leader in the application of conservation plans, the outputs of which are widely used for spatial planning and decision making in many spheres of government. We aimed to determine how conservation planning in the country progressed from theory to implementation, and to identify practical actions that enabled this transition, by assessing temporal trends in the characteristics of conservation plans (1990–2017, n = 94). Since 2010 conservation planning has entered an operational period characterized by government leadership of plans, administrative rather than ecological planning domains, decreasing size of planning units, increasing emphasis on end-user products, and scheduled revision of plans. Key actions that enabled this progression include transitioning leadership of plans from scientists to practitioners, building capacity within implementing agencies, creating opportunities to integrate plans in legislative processes, establishing a strong community of practice, adopting implementation-focused methods, and balancing standardization with innovation. Learning from this model will allow other countries, particularly those with a similar megadiverse, developing context, to operationalize conservation planning into spatial planning and decision making. 相似文献
Regional Environmental Change - Geographic information systems are a means to develop a common framework for the integration of a range of perspectives into natural resources management decisions.... 相似文献
This study presents a transnational groundwater survey of the 62,000 km(2) Mekong delta floodplain (Southern Vietnam and bordering Cambodia) and assesses human health risks associated with elevated concentrations of dissolved toxic elements. The lower Mekong delta generally features saline groundwater. However, where groundwater salinity is <1 g L(-)(1) Total Dissolved Solids (TDS), the rural population started exploiting shallow groundwater as drinking water in replacement of microbially contaminated surface water. In groundwater used as drinking water, arsenic concentrations ranged from 0.1-1340 microg L(-)(1), with 37% of the studied wells exceeding the WHO guidelines of 10 microg L(-)(1) arsenic. In addition, 50% exceeded the manganese WHO guideline of 0.4 mg L(-)(1), with concentrations being particularly high in Vietnam (range 1.0-34 mg L(-)(1)). Other elements of (minor) concern are Ba, Cd, Ni, Se, Pb and U. Our measurements imply that groundwater contamination is of geogenic origin and caused by natural anoxic conditions in the aquifers. Chronic arsenic poisoning is the most serious health risk for the ~2 million people drinking this groundwater without treatment, followed by malfunction in children's development through excessive manganese uptake. Government agencies, water specialists and scientists must get aware of the serious situation. Mitigation measures are urgently needed to protect the unaware people from such health problems. 相似文献
Objective: Statistics indicate that employees commuting or traveling as part of their work are overrepresented in workplace injury and death. Despite this, many organizations are unaware of the factors within their organizations that are likely to influence potential reductions in work-related road traffic injury.
Methods: This article presents a multilevel conceptual framework that identifies health investment as the central feature in reducing work-related road traffic injury. Within this framework, we explore factors operating at the individual driver, workgroup supervisor, and organizational senior management levels that create a mutually reinforcing system of safety.
Results: The health investment framework identifies key factors at the senior manager, supervisor, and driver levels to cultivating a safe working environment. These factors are high-performance workplace systems, leader–member exchange and autonomy, trust and empowerment, respectively. The framework demonstrates the important interactions between these factors and how they create a self-sustaining organizational safety system.
Conclusions: The framework aims to provide insight into the future development of interventions that are strategically aligned with the organization and target elements that facilitate and enhance driver safety and ultimately reduce work-related road traffic injury and death. 相似文献
There are many established extraction techniques regularly used in the isolation and analysis of PAHs and similar organic compounds from various phases. These include Soxhlet or ultrasonic extractions from solids, and liquid-liquid or solid-phase extraction from aqueous samples. However, these methods have some inherent disadvantages; most require large volumes of organic solvents, they can be time consuming and many involve multi-step processes that always present the risk of the loss of some analytes (Zhang et al., 1994). Solid-phase micro-extraction (SPME) is a relatively new technique that has been used with much success in the analysis of a variety of compounds including PAHs. Experiments are being carried out to determine the optimum range of conditions for the extraction of a range of PAHs. Parameters under investigation include temperature, equilibration time, salinity and compound concentration. Presented here are some preliminary experiments into the applicability of SPME for PAH analysis. Further work will investigate the reproducibility of the technique, limits of detection and matrix effects. When an optimised method has been developed the technique will be used in investigations into PAH profiles in sediment cores. 相似文献
Effective monitoring of selective logging from remotely sensed data requires an understanding of the spatial and temporal thresholds that constrain the utility of those data, as well as the structural and ecological characteristics of forest disturbances that are responsible for those constraints. Here we assess those thresholds and characteristics within the context of selective logging in the Bolivian Amazon. Our study combined field measurements of the spatial and temporal dynamics of felling gaps and skid trails ranging from <1 to 19 months following reduced-impact logging in a forest in lowland Bolivia with remote-sensing measurements from simultaneous monthly ASTER satellite overpasses. A probabilistic spectral mixture model (AutoMCU) was used to derive per-pixel fractional cover estimates of photosynthetic vegetation (PV), non-photosynthetic vegetation (NPV), and soil. Results were compared with the normalized difference in vegetation index (NDVI). The forest studied had considerably lower basal area and harvest volumes than logged sites in the Brazilian Amazon where similar remote-sensing analyses have been performed. Nonetheless, individual felling-gap area was positively correlated with canopy openness, percentage liana coverage, rates of vegetation regrowth, and height of remnant NPV. Both liana growth and NPV occurred primarily in the crown zone of the felling gap, whereas exposed soil was limited to the trunk zone of the gap. In felling gaps >400 m2, NDVI, and the PV and NPV fractions, were distinguishable from unlogged forest values for up to six months after logging; felling gaps <400 m2 were distinguishable for up to three months after harvest, but we were entirely unable to distinguish skid trails from our analysis of the spectral data. 相似文献