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21.
A refugium is generally understood as an area where temperate species survive cold periods, such as the Iberian, Italian, or Balkan Peninsulas in Europe. Strictly speaking, this definition refers to what is known as a glacial refugium. However, there are various types of lesser-known refugia such as the interglacial refugium, which denotes a mountainous region at low latitudes, such as the Pyrenees, where species adapted to the cold survive during interstadial periods. The small-vertebrate association from the sequence of Cova Colomera, which is located on the southern face of the Pyrenees and contains the final cold spell of the Late Pleistocene and the beginnings of the temperate period in which we currently find ourselves (the Holocene), could constitute the first fossil evidence of such an interglacial refugium, thus providing new paleoecological data on the phenomenon.  相似文献   
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Eight species of desert vegetation and associated soils were collected from the Nevada National Security Site (N2S2) and analyzed for 238Pu and 239 + 240Pu concentrations. Amongst the plant species sampled were: atmospheric elemental accumulators (moss and lichen), the very slow growing, long-lived creosote bush and the rapidly growing, short-lived cheatgrass brome. The diversity of growth strategies provided insight into the geochemical behavior and bio-availability of Pu at the N2S2. The highest concentrations of Pu were measured in the onion moss (24.27 Bq kg-1 238Pu and 52.78 Bq kg-1 239 + 240Pu) followed by the rimmed navel lichen (8.18 Bq kg-1 and 18.4 Bq kg-1 respectively), pointing to the importance of eolian transport of Pu. Brome and desert globemallow accumulated between 3 and 9 times higher concentrations of Pu than creosote and sage brush species. These results support the importance of species specific elemental accumulation strategies rather than exposure duration as the dominant variable influencing Pu concentrations in these plants. Total vegetation elemental concentrations of Ce, Fe, Al, Sm and others were also analyzed. Strong correlations were observed between Fe and Pu. This supports the conclusion that Pu was accumulated as a consequence of the active accumulation of Fe and other plant required nutrients. Cerium and Pu are considered to be chemical analogs. Strong correlations observed in plants support the conclusion that these elements displayed similar geochemical behavior in the environment as it related to the biochemical uptake process of vegetation. Soils were also sampled in association with vegetation samples. This allowed for the calculation of a concentration ratio (CR). The CR values for Pu in plants were highly influenced by the heterogeneity of Pu distribution among sites. Results from the naturally occurring elements of concern were more evenly distributed between sample sites. This allowed for the development of a pattern of plant species that accumulated Ce, Sm, Fe and Al. The highest accumulators of these elements were onion moss, lichen flowed by brome. The lowest accumulators were creosote bush and fourwing saltbush. This ranked order corresponds to plant accumulations of Pu.  相似文献   
24.
This paper2 provides a snapshot of the mental health situation in South Sudan between 2013 and 2016, taking account of the personal reflections of both authors who were engaged in mental health and psychosocial support (MHPSS)3 programming in the country at this time.4 It begins by presenting an overview of MHPSS activities from this period, including governmental and non‐governmental organisation (NGO) services, and relevant research and coordination mechanisms. It goes on to illustrate the challenges to the provision of support, as well as the overarching structural, governance, and human resource constraints faced by the sector. Finally, recommendations are put forward for improving services and care for people suffering from psychosocial and mental health issues, as well as suggestions for areas of focus in the future. The importance of an integrated, community‐based model is emphasised, and opportunities for organisations engaged in reconciliation efforts and mental health service provision to collaborate are proposed.  相似文献   
25.
Circuit-theory applications to connectivity science and conservation   总被引:1,自引:0,他引:1  
Conservation practitioners have long recognized ecological connectivity as a global priority for preserving biodiversity and ecosystem function. In the early years of conservation science, ecologists extended principles of island biogeography to assess connectivity based on source patch proximity and other metrics derived from binary maps of habitat. From 2006 to 2008, the late Brad McRae introduced circuit theory as an alternative approach to model gene flow and the dispersal or movement routes of organisms. He posited concepts and metrics from electrical circuit theory as a robust way to quantify movement across multiple possible paths in a landscape, not just a single least-cost path or corridor. Circuit theory offers many theoretical, conceptual, and practical linkages to conservation science. We reviewed 459 recent studies citing circuit theory or the open-source software Circuitscape. We focused on applications of circuit theory to the science and practice of connectivity conservation, including topics in landscape and population genetics, movement and dispersal paths of organisms, anthropogenic barriers to connectivity, fire behavior, water flow, and ecosystem services. Circuit theory is likely to have an effect on conservation science and practitioners through improved insights into landscape dynamics, animal movement, and habitat-use studies and through the development of new software tools for data analysis and visualization. The influence of circuit theory on conservation comes from the theoretical basis and elegance of the approach and the powerful collaborations and active user community that have emerged. Circuit theory provides a springboard for ecological understanding and will remain an important conservation tool for researchers and practitioners around the globe.  相似文献   
26.
OBJECTIVE: The lower extremity is among the most frequently injured body regions for children restrained by forward facing child restraint systems (FFCRS), accounting for 28% of their clinically significant injuries, defined as AIS 2 and greater injuries excluding concussions. Despite the prevalence of these injuries, the current U.S. Motor Vehicle Safety Standard governing FFCRS (FMVSS 213) does not provide a direct assessment of the biomechanical risk of lower extremity fracture nor do the current pediatric test devices provide adequate instrumentation to detect the risk of such injuries. Before improvements can be made to the anthropometric test devices (ATDs) or test procedures to address these limitations, understanding of the sources and mechanisms of these injuries is necessary. Therefore, the objective of this study was to document location, source, and crash circumstances of lower extremity injuries in children seated in FFCRS. METHODS: Utilizing two sources of data, PCPS and CIREN, 20 in-depth investigations of crashes involving children seated in FFCRS with lower extremity injuries were reviewed to determine the nature of the injuries and the circumstances under which they occurred. RESULTS: Injuries below the knee were the most common, particularly to the tibia/fibula, and they most often occurred due to interaction with the vehicle seatback in front of the child's seating position. These injuries were sustained most commonly in frontal impacts although interaction with the seatback also occurred in other crash types. This interaction with the seatback was exacerbated by possible contributing factors such as intrusion of the front seatback into the child's occupant space or FFCRS misuse resulting in increased excursion of the child during impact. CONCLUSIONS: This review of cases of children in FFCRS with AIS 2 and greater lower extremity injury points to the role of the seatback in the occurrence of these injuries, suggesting the need to consider this interaction in the seatback design process and to adequately represent this interaction in regulatory procedures assessing the performance of child restraints.  相似文献   
27.
Many of the problems faced by international projects intending to create adaptive social–ecological systems for climate change stem from lack of stakeholder engagement, limited understanding of local political, economic, and environmental complexities, and restricted time. Local organizations focused on conservation and development might have an advantage in creating adaptive social–ecological systems because they understand local processes and are involved with communities for extended periods of time. A local non-governmental organization, Asociación Ecosistemas Andinos (ECOAN), works in twenty-one communities in the Andean highlands outside of Cusco to conserve the endangered Polylepis forests. As part of the conservation project, ECOAN supports community-led development projects such as building greenhouses. Data for this project were gathered through interviews (with community members in three different communities, ECOAN staff, and donors) and participant observation. This paper shows that ECOAN’s extensive use of participation has led to community ownership of the conservation and development projects. The communities’ close connections to the Polylepis project contribute to resilience through creating networks, extending the local environmental ethic to the Polylepis trees, supporting projects that diversify and strengthen community sustenance, and contributing to the growth of economic activities. This case study provides a positive example of the potential for local organizations and people to take charge of their own resiliency efforts where international projects and protocols may otherwise prove ineffective.  相似文献   
28.
Standardized classification methods based on quantifiable risk metrics are critical for evaluating extinction threats because they increase objectivity, consistency, and transparency of listing decisions. Yet, in the United States, neither federal nor state agencies use standardized methods for listing species for legal protection, which could put listing decisions at odds with the magnitude of the risk. We used a recently developed set of quantitative risk metrics for California herpetofauna as a case study to highlight discrepancies in listing decisions made without standardized methods. We also combined such quantitative metrics with classification tree analysis to attempt to increase the transparency of previous listing decisions by identifying the criteria that had inherently been given the most weight. Federally listed herpetofauna in California scored significantly higher on the risk-metric spectrum than those not federally listed, whereas state-listed species did not score any higher than species that were not state listed. Based on classification trees, state endemism was the most important predictor of listing status at the state level and distribution trend (decline in a species’ range size) and population trend (decline in a species’ abundance at localized sites) were the most important predictors at the federal level. Our results emphasize the need for governing bodies to adopt standardized methods for assessing conservation risk that are based on quantitative criteria. Such methods allow decision makers to identify criteria inherently given the most weight in determining listing status, thus increasing the transparency of previous listing decisions, and produce an unbiased comparison of conservation threat across all species to promote consistency, efficiency, and effectiveness of the listing process.  相似文献   
29.
The Endangered Species Act (ESA) of the United States was enacted in 1973 to prevent the extinction of species. Recovery plans, required by 1988 amendments to the ESA, play an important role in organizing these efforts to protect and recover species. To improve the use of science in the recovery planning process, the Society for Conservation Biology (SCB) commissioned an independent review of endangered species recovery planning in 1999. From these findings, the SCB made key recommendations for how management agencies could improve the recovery planning process, after which the U.S. Fish and Wildlife Service and the National Marine Fisheries Service redrafted their recovery planning guidelines. One important recommendation called for recovery plans to make threats a primary focus, including organizing and prioritizing recovery tasks for threat abatement. We sought to determine the extent to which results from the SCB study were incorporated into these new guidelines and whether the SCB recommendations regarding threats manifested in recovery plans written under the new guidelines. Recovery planning guidelines generally incorporated the SCB recommendations, including those for managing threats. However, although recent recovery plans have improved in their treatment of threats, many fail to adequately incorporate threat monitoring. This failure suggests that developing clear guidelines for monitoring should be an important priority in improving ESA recovery planning.  相似文献   
30.
Increasing connectivity is an important strategy for facilitating species range shifts and maintaining biodiversity in the face of climate change. To date, however, few researchers have included future climate projections in efforts to prioritize areas for increasing connectivity. We identified key areas likely to facilitate climate‐induced species’ movement across western North America. Using historical climate data sets and future climate projections, we mapped potential species’ movement routes that link current climate conditions to analogous climate conditions in the future (i.e., future climate analogs) with a novel moving‐window analysis based on electrical circuit theory. In addition to tracing shifting climates, the approach accounted for landscape permeability and empirically derived species’ dispersal capabilities. We compared connectivity maps generated with our climate‐change‐informed approach with maps of connectivity based solely on the degree of human modification of the landscape. Including future climate projections in connectivity models substantially shifted and constrained priority areas for movement to a smaller proportion of the landscape than when climate projections were not considered. Potential movement, measured as current flow, decreased in all ecoregions when climate projections were included, particularly when dispersal was limited, which made climate analogs inaccessible. Many areas emerged as important for connectivity only when climate change was modeled in 2 time steps rather than in a single time step. Our results illustrate that movement routes needed to track changing climatic conditions may differ from those that connect present‐day landscapes. Incorporating future climate projections into connectivity modeling is an important step toward facilitating successful species movement and population persistence in a changing climate.  相似文献   
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