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241.
Social individuals have organized relationships that affect fitness and so a species' tendency to be social has important implications for its population ecology, gene flow, and its distribution in space and time. We quantitatively examined the social structure of southern flying squirrels (Glaucomys volans) and tested for a role of kinship and prior familiarity in predicting social structure. To quantify social structure, we monitored nest group composition of southern flying squirrels. All squirrels at the study site were marked with passive integrated transponder (PIT) tags and nest cavity entrances were monitored with automated PIT tag recorders for a period of 28 months. Squirrels were genotyped at eight microsatellite loci. Permutation tests of associations suggested that individuals nested with other specific individuals more often than expected by chance. The lagged association rate indicated that relationships were stable and persisted across seasons and years. Multiple summer nest associates came together in winter to form larger nest groups which were likely important for social thermoregulation. A measure of prior familiarity, but not kinship, was related to the proportion of time individuals nested together during winter. We suggest that the evolution of sociality in southern flying squirrels is driven largely by mutually beneficial behaviors related to social thermoregulation although other, as of yet, unidentified mechanisms are needed to explain sociality in the warm season. We hypothesize that minimum group size requirements associated with social thermoregulation could explain the absence of this species in patchy landscapes and aspects of range boundary dynamics near their northern range boundary.  相似文献   
242.
Establishment and maintenance of the reproductive division of labor within social insect colonies relies on clear communication between nestmates. Fertile members convey their status to prevent others from becoming reproductively active. Recent findings in some basal termites indicate that cuticular hydrocarbon profiles may indicate reproductive state, but there is little evidence to show a direct link between reproductive status and hydrocarbon production—a prerequisite for an “honest” fertility signal. Here, we report that the putative signaling mechanism is influenced by juvenile hormone (JH), a primary regulator of gonadal development and activity in insects. Topical application of a JH-analog (pyriproxyfen) to reproductively inactive alates of the basal dampwood termite Zootermopsis nevadensis induced both females and males to express significantly more of a reproductive-specific hydrocarbon (6,9,17-tritriacontatriene). However, the JH-analog did not significantly enhance gonadal development or activity in treated termites beyond what is usually observed in maturing alates released from the inhibitory stimuli of their natal nest. These results suggest that a rise in JH following disinhibition drives the expression of reproductive-specific hydrocarbons, but that an individual’s hydrocarbon profile is not directly linked to its gonadal state. Rather than directly driving the expression of reproductive-specific hydrocarbons, the gonads may act indirectly through their influence on circulating JH.  相似文献   
243.
Climate change is increasing the need to characterise the vulnerability of coastal landscapes to coastal and flood hazards that result in erosion and inundation. Indices, such as the Coastal Vulnerability Index (CVI), have emerged as useful tools with which coastal managers can prioritise areas for further detailed assessment of vulnerability, risk, resilience and adaptation options. Approaches, such as the use of an index, efficiently characterise the vulnerability of linear, one-dimensional coastal features such as coastlines; however, they do not capture variability in coastal processes affecting more complex, non-linear features, such as estuaries, or interactive effects of coastal processes between linear (e.g. coastlines) and non-linear (e.g. estuaries) landforms. We present an approach that uses geomorphology to indicate biophysical vulnerability of estuaries to coastal and flood hazards. The approach is applied to the South Coast of NSW; a wave-dominated coastline of approximately 400 km length that contains more than 100 estuaries. We demonstrate the simplicity of the approach and its utility in identifying areas requiring higher resolution assessments. Although this approach does not include socio-economic factors, we demonstrate the capacity to incorporate socio-economic components of vulnerability using regional land use mapping. We infer that the most vulnerable estuaries are characterised by large catchment areas, broad estuarine valleys, mature stages of infill, or entrances oriented towards the prevailing wave direction. The area below 15 m elevation was identified as a robust indicator of the total area of vulnerability within a catchment. This approach can be applied to one-dimensional and more complex two-dimensional landscapes, such as estuaries; integrates varying sea-level rise projections; and incorporates a wider range of hazards that operate in the coastal zone.  相似文献   
244.
Many of the world’s coasts appear vulnerable to the impacts of climate change and sea-level rise. This paper assesses the application of a coastal sensitivity index (CSI) to the Illawarra coast, a relatively well-studied shoreline in southeast Australia. Nine variables, namely (a) rock type, (b) coastal slope (c) geomorphology (d) barrier type (e) shoreline exposure (f) shoreline change (g) relative sea-level rise (h) mean wave height and (j) mean tide range, were adopted in calculation of the CSI (the square root of the product of the ranked variables divided by the number of variables). Two new variables, shoreline exposure and barrier type, were trialled in this analysis and the extent to which these increased the discriminatory power of the index was assessed. Four iterations of the CSI were undertaken using different combinations of ranked variables for each of 105 cells in a grid template, and the index values derived were displayed based on quartiles, indicating sections of coast with very high, high, moderate and low sensitivity. Increasing the number of variables increased the discriminatory power of the index, but the broad pattern and the rank order were very similar for each of the iterations. Rocky and cliffed sections of coast are least sensitive whereas sandy beaches backed by low plains or dunes record the highest sensitivity. It is difficult to determine shoreline change on this coast, because individual storms result in substantial erosion of beaches, but there are prolonged subsequent periods of accretion and foredune rebuilding. Consequently this variable is not a good indicator of shoreline sensitivity and the index is unlikely to provide a clear basis for forecasting future recession of beaches. The results of this study provide a framework for coastal managers and planners to prioritize efforts to enhance the resilience or consider adaptation measures in the coastal zone within a study region. Sensitivity of the coast if considered in conjunction with other social factors may be an input into broader assessments of the overall vulnerability of coasts and their communities.  相似文献   
245.
A generalized quantitative risk assessment for the use of source-segregated green waste (SSGW) compost use in livestock production is presented. This assessment focussed on potential risks associated with a specific product, PAS100 compost that meets the UK publicly available specification 100 and represents the majority of compost available for use in extensive Scottish livestock systems. A hazard screening approach was used to identify all potentially hazardous agents present in compost. A total of 497 potentially hazardous agents were screened, with 147 finally put forward for quantitative risk assessment. Scenarios modelled in the assessment included surface application of compost to grazing land and also incorporation into soil and subsequent uptake by fodder crops. Risk estimates were compared to those associated with six comparator materials, including various sludges, slurries and farm yard manures. Overall, five potentially hazardous agents (PCB28, PCB138, PCB153, 1,2,3,4,6,7,8-HpCDD, Clopyralid) returned a hazard quotient >1 but within margins of uncertainty, indicating that further investigation may be required. Within the limitations of available information, SSGW compost was found to pose less risk to grazing livestock, or the environment, than other commonly-used soil amendments. While this assessment relates to a specific product/standard used in the UK, the methodology could easily be applied to other composts/products/situations. Therefore these results have wider applicability.  相似文献   
246.
The semi-arid Amboseli landscape, southern Kenya, is characterised by intermittent groundwater-fed wetlands that form sedimentary geoarchives recording past ecosystem changes. We present a 5000-year environmental history of a radiocarbon dated sediment core from Esambu Swamp adjacent to Amboseli National Park. Although radiocarbon dates suggest an unconformity or sedimentary gap that spans between 3800 and 500 cal year BP, the record provides a unique insight into the long-term ecosystem history and wetland processes, particularly the past 500 years. Climatic shifts, fire activity and recent anthropogenic activity drive changes in ecosystem composition. Prior to 3800 cal year BP the pollen data suggest semi-arid savanna ecosystem persisted near the wetland. The wetland transgressed at some time between 3800 and 500 cal year BP and it is difficult to constrain this timing further, and palustrine peaty sediments have accumulated since 400 cal year BP. Increased abundance of Afromontane forest taxa from adjacent highlands of Kilimanjaro and the Chyulu Hills and local arboreal taxa reflect changes in regional moisture budgets. Particularly transformative changes occurred in the last five centuries, associated with increased local biomass burning coeval with the arrival of Maa-speaking pastoralists and intensification of the ivory trade. Cereal crops occurred consistently from around 300 cal year BP, indicative of further anthropogenic activity. The study provides unique insight in Amboseli ecosystem history and the link between ecosystem drivers of change. Such long-term perspectives are crucial for future climate change and associated livelihood impacts, so that suitable responses to ensure sustainable management practices can be developed in an important conservation landscape.  相似文献   
247.
Recent interest in expanding offshore oil production within waters of the United States has been met with opposition by groups concerned with recreational, environmental, and aesthetic values associated with the coastal zone. Although the proposition of new oil platforms off the coast has generated conflict over how coastal resources should be utilized, little research has been conducted on where these user conflicts might be most intense and which sites might be most suitable for locating oil production facilities in light of the multiple, and often times, competing interests. In this article, we develop a multiple-criteria spatial decision support tool that identifies the potential degree of conflict associated with oil and gas production activities for existing lease tracts in the coastal margin of Texas. We use geographic information systems to measure and map a range of potentially competing representative values impacted by establishing energy extraction infrastructure and then spatially identify which leased tracts are the least contentious sites for oil and gas production in Texas state waters. Visual and statistical results indicate that oil and gas lease blocks within the study area vary in their potential to generate conflict among multiple stakeholders.  相似文献   
248.
The concomitant recycling of waste and carbon dioxide emissions is the subject of developing technology designed to close the industrial process loop and facilitate the bulk-re-use of waste in, for example, construction. The present work discusses a treatment step that employs accelerated carbonation to convert gaseous carbon dioxide into solid calcium carbonate through a reaction with industrial thermal residues. Treatment by accelerated carbonation enabled a synthetic aggregate to be made from thermal residues and waste quarry fines. The aggregates produced had a bulk density below 1000 kg/m3 and a high water absorption capacity. Aggregate crushing strengths were between 30% and 90% stronger than the proprietary lightweight expanded clay aggregate available in the UK. Cast concrete blocks containing the carbonated aggregate achieve compressive strengths of 24 MPa, making them suitable for use with concrete exposed to non-aggressive service environments. The energy intensive firing and sintering processes traditionally required to produce lightweight aggregates can now be augmented by a cold-bonding, low energy method that contributes to the reduction of green house gases to the atmosphere.  相似文献   
249.
Current methods for tracking pathogens across farmland and into surrounding waterways via runoff are limited and typically have been developed using artificially created landscapes. No studies have investigated how Giardia in farm runoff moves across the landscape, despite high prevalence rates in dairy cattle (Bos taurus) worldwide. Here, we report the development of a field-based tracking method specific for Giardia movement in runoff and use this technique to compare the pathogen reduction capability of recently planted vegetation strips with bare soil strips cleared of vegetation. Such scenarios represent typical events in schemes to plant vegetation barriers aimed at reducing waterway contamination. A significant treatment effect was identified, with 26% fewer Giardia detected in runoff collected from the planted strip (P = 0.006). These results highlight the immediate benefit of pathogen removal to be gained from vegetation planting. The successful discrimination of treatment effects by this new technique will enable the assessment of different vegetation types on runoff reduction and the effects of plant development over time.  相似文献   
250.

Background, aim, and scope  

The need for global and integrated approaches to water resources management, both from the quantitative and the qualitative point of view, has long been recognized. Water quality management is a major issue for sustainable development and a mandatory task with respect to the implementation of the European Water Framework Directive as well as the Swiss legislation. However, data modelling to develop relational databases and subsequent geographic information system (GIS)-based water management instruments are a rather recent and not that widespread trend. The publication of overall guidelines for data modelling along with the EU Water Framework Directive is an important milestone in this area. Improving overall water quality requires better and more easily accessible data, but also the possibility to link data to simulation models. Models are to be used to derive indicators that will in turn support decision-making processes. For this whole chain to become effective at a river basin scale, all its components have to become part of the current daily practice of the local water administration. Any system, tool, or instrument that is not designed to meet, first of all, the fundamental needs of its primary end-users has almost no chance to be successful in the longer term.  相似文献   
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