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排序方式: 共有83条查询结果,搜索用时 46 毫秒
41.
Alec P. Christie Tatsuya Amano Philip A. Martin Silviu O. Petrovan Gorm E. Shackelford Benno I. Simmons Rebecca K. Smith David R. Williams Claire F. R. Wordley William J. Sutherland 《Conservation biology》2021,35(1):249-262
Efforts to tackle the current biodiversity crisis need to be as efficient and effective as possible given chronic underfunding. To inform decision-makers of the most effective conservation actions, it is important to identify biases and gaps in the conservation literature to prioritize future evidence generation. We used the Conservation Evidence database to assess the state of the global literature that tests conservation actions for amphibians and birds. For the studies in the database, we investigated their spatial and taxonomic extent and distribution across biomes, effectiveness metrics, and study designs. Studies were heavily concentrated in Western Europe and North America for birds and particularly for amphibians, and temperate forest and grassland biomes were highly represented relative to their percentage of land coverage. Studies that used the most reliable study designs—before-after control-impact and randomized controlled trials—were the most geographically restricted and scarce in the evidence base. There were negative spatial relationships between the numbers of studies and the numbers of threatened and data-deficient species worldwide. Taxonomic biases and gaps were apparent for amphibians and birds—some entire orders were absent from the evidence base—whereas others were poorly represented relative to the proportion of threatened species they contained. Metrics used to evaluate effectiveness of conservation actions were often inconsistent between studies, potentially making them less directly comparable and evidence synthesis more difficult. Testing conservation actions on threatened species outside Western Europe, North America, and Australasia should be prioritized. Standardizing metrics and improving the rigor of study designs used to test conservation actions would also improve the quality of the evidence base for synthesis and decision-making. 相似文献
42.
43.
Sustainability has become an increasingly used term, but what does it mean in terms of practice. This research will look at
the harvesting of captured stormwater for the irrigation of urban playing fields and what the implications are for catchment
hydrology, local community, and local council. This research aims to identify, understand and determine the catchment conditions
that may hinder the stormwater quality and quantity for capture and reuse, as well as determining whether the stormwater harvesting
will be sustainable. Research methods for this project will include systemic analysis in order to further investigate the
assumptions being made in the study.
Manly Golf Club has relied on groundwater extraction supplemented by potable supplies for irrigation, however potable supplies
are no longer available. It has been proposed to provide irrigation supplies from stormwater via onsite storage and groundwater
recharge. Monitored stormwater entering the Golf Course from the adjacent Cemetery Creek sub-catchment for pollutants, have
indicated that it may be suitable for irrigation with treatment and may reduce problems generated by overuse of groundwater.
The proposal will provide environmental benefit through reduced pollution loads being discharged directly to receiving waters
and cessation of use of potable supplies by the Club. Social and economic benefits are expected to be gained and will be monitored
as part of an ongoing research program. 相似文献
44.
Sperm competition as a mechanism of female choice in the field cricket,Gryllus bimaculatus 总被引:9,自引:0,他引:9
L. W. Simmons 《Behavioral ecology and sociobiology》1987,21(3):197-202
Summary While traditionally viewed as an extension of intermale competition, mechanisms of sperm competition may be used by multiply mating females for mate choice. In the field cricket G. bimaculatus sperm were shown to mix in the spermatheca. The proportion of offspring sired by the second male increased with spermatophore attachment duration and, therefore, the number of sperm transferred. There was no second male advantage for single matings after an initial double mating. However, the proportion ofoffspring sired by the second male increased in proportion to the number of times he mated such that second males mating three times after an initial double mating had the advantage at fertilization. The data suggested that sperm were utilized in proportion to their numerical representation in the spermatheca. The mechanism of sperm precedence may, therefore, be one of sperm dilution. Female G. bimaculatus may control the degree of sperm competition as a mechanism of mate choice. By accepting large quantities of sperm from chosen males they may determine the paternity of their offspring by diluting out the sperm stored from previous matings. 相似文献
45.
Summary Seasonal variation in mean hind tibia length and mean testes length is investigated in the yellow dung fly, Scathophaga stercoraria (L.). There is a cycle in mean hind tibia length and mean testes length over a season. The body size curve peaks later than the testes length curve, showing that there is no fixed relationship between the two variables. The causes of variation in testes size and its influence on copula duration are experimentally examined. Increasing the number of Drosophila eaten per day leads to increased mature testes length. Males with larger testes copulate for longer than males with smaller ones, and smaller males copulate for longer than do larger males. While testes shrivel with successive copulas, copula duration remains constant. The more females a male is prepared to copulate with in a day (up to five), the longer he copulates with each. The shrinkage of the testes of males collected throughout a day suggests that males copulate with an average of 4 females per day. The costs of sperm production are thus shown to have a significant influence on the copula duration.Offprint requests to: P.I. Ward at the second address 相似文献
46.
Forest to reclaimed mine land use change leads to altered ecosystem structure and function. 总被引:1,自引:0,他引:1
Jeffrey A Simmons William S Currie Keith N Eshleman Karen Kuers Susan Monteleone Tim L Negley Bob R Pohlad Carolyn L Thomas 《Ecological applications》2008,18(1):104-118
The United States' use of coal results in many environmental alterations. In the Appalachian coal belt region, one widespread alteration is conversion of forest to reclaimed mineland. The goal of this study was to quantify the changes to ecosystem structure and function associated with a conversion from forest to reclaimed mine grassland by comparing a small watershed containing a 15-year-old reclaimed mine with a forested, reference watershed in western Maryland. Major differences were apparent between the two watersheds in terms of biogeochemistry. Total C, N, and P pools were all substantially lower at the mined site, mainly due to the removal of woody biomass but also, in the case of P, to reductions in soil pools. Mineral soil C, N, and P pools were 96%, 79%, and 69% of native soils, respectively. Although annual runoff from the watersheds was similar, the mined watershed exhibited taller, narrower storm peaks as a result of a higher soil bulk density and decreased infiltration rates. Stream export of N was much lower in the mined watershed due to lower net nitrification rates and nitrate concentrations in soil. However, stream export of sediment and P and summer stream temperature were much higher. Stream leaf decomposition was reduced and macroinvertebrate community structure was altered as a result of these changes to the stream environment. This land use change leads to substantial, long-term changes in ecosystem capital and function. 相似文献
47.
This paper aims to contribute to the ongoing debate on the use of resource accounting tools in regional policy-making. The Northern Limits project applied material flow analysis (MFA) and ecological footprinting (EF) to regional policy-making in Northern Ireland over a number of years. The early phase of the research informed the regions first sustainable development strategy which was published in 2006 with key targets relating to the EF and improving the resource efficiency of the economy. Phase II identified the next steps required to address data availability and quality and the use of MFA and EF in providing a measurement and monitoring framework for the strategy and the development of the strategy implementation plan. The use of MFA and EF in sustainable regional policy-making and the monitoring of its implementation is an ongoing process which has raised a number of research issues which can inform the ongoing application and development of these and other resource accounting tools to within Northern Ireland, provide insights for their use in other regions, and help set out the priorities for research to support this important policy area. 相似文献
48.
Trails created by off-road vehicles (ORV) in boreal lowlands are known to cause local impacts, such as denuded vegetation,
soil erosion, and permafrost thaw, but impacts on stream and watershed processes are less certain. In Wrangell-St. Elias National
Park and Preserve (WRST), Alaska, ORV trails have caused local resource damage in intermountain lowlands with permafrost soils
and abundant wetlands and there is a need to know whether these impacts are more extensive. Comparison of aerial photography
from 1957, 1981, and 2004 coupled with ground surveys in 2009 reveal an increase in trail length and number and show an upslope
expansion of a trail system around points of stream channel initiation. We hypothesized that these impacts could also cause
premature initiation and headward expansion of channels because of lowered soil resistance and greater runoff accumulation
as trails migrate upslope. Soil monitoring showed earlier and deeper thaw of the active layer in and adjacent to trails compared
to reference sites. Several rainfall-runoff events during the summer of 2009 showed increased and sustained flow accumulation
below trail crossings and channel shear forces sufficient to cause headward erosion of silt and peat soils. These observations
of trail evolution relative to stream and wetland crossings together with process studies suggest that ORV trails are altering
watershed processes. These changes in watershed processes appear to result in increasing drainage density and may also alter
downstream flow regimes, water quality, and aquatic habitat. Addressing local land-use disturbances in boreal and arctic parklands
with permafrost soils, such as WRST, where responses to climate change may be causing concurrent shifts in watershed processes,
represents an important challenge facing resource managers. 相似文献
49.
Understanding how private landholders make deforestation decisions is of paramount importance for conservation. Behavioural frameworks from the social sciences have a lot to offer researchers and practitioners, yet these insights remain underutilised in describing what drives landholders’ deforestation intentions under important political, social, and management contexts. Using survey data of private landholders in Queensland, Australia, we compare the ability of two popular behavioural models to predict future deforestation intentions, and propose a more integrated behavioural model of deforestation intentions. We found that the integrated model outperformed other models, revealing the importance of threat perceptions, attitudes, and social norms for predicting landholders’ deforestation intentions. Social capital, policy uncertainty, and years of experience are important contextual moderators of these psychological factors. We conclude with recommendations for promoting behaviour change in this deforestation hotspot and highlight how others can adopt similar approaches to illuminate more proximate drivers of environmental behaviours in other contexts.Supplementary informationThe online version of this article (10.1007/s13280-020-01491-w) contains supplementary material, which is available to authorized users. 相似文献
50.
W R Roy I G Krapac S F Chou F W Simmons 《Journal of environmental science and health. Part. B》2001,36(3):245-260
The chemical fate and movement of pesticides may be subject to transient storage in unsaturated soils during periods of light rainfall, and subsequent release into shallow groundwater by increased rainfall. The objective of this study was to conduct field-scale experiments to determine the relative importance of transient storage and subsequent release of agrichemicals from the vadose zone into potential aquifers. Two field-scale experiments were conducted under a rain exclusion shelter. In the 1x experiment, atrazine and chlorpyrifos were applied at application-rate equivalents (1.6 kg ha(-1) and 1.3 kg ha(-1), respectively). In the 4x experiment, atrazine was applied in an amount that was four times greater than that usually applied to fields (6.7 kg ha(-1)). Water was either applied to simulate rain or withheld to simulate dry periods. In the 1x experiment, atrazine was detected in the water samples whereas chlorpyrifos was not detected in the majority of the samples. The dry period imposed on the treatment plot did not appear to result in storage of the chemicals, whereas the wet period resulted in greater leaching of atrazine, although the concentrations remained less than the Maximum Contaminant Level of 3 microg L(-1). Both chemicals were detected in soil samples collected from a 20- to 30-cm depth, but it appeared that both chemicals dissipated before the field experiment was concluded. It appeared that the one-time application of atrazine and chlorpyrifos at the label rates did not result in a sufficient mass to be stored and flushed in significant concentrations to the saturated zone. When atrazine was applied at 4x and a longer drought period was imposed on the treatment plot, the resulting concentrations of dissolved atrazine were still less than 3 microg L(-1) . Atrazine was detected in only the near-surface (0 to 15 cm) soil samples and the herbicide dissipated before the onset of the dry period in the treatment plot. The results of this field study demonstrated that atrazine and chlorpyrifos were not sufficiently persistent to be stored and then released in significantly large concentrations to the saturated zone. The dissipation half-life of atrazine in the 4x application was about 44 days. This study, in addition to others, suggested that atrazine may be less persistent in surface soil than has been generally reported. 相似文献