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171.
Will Allen Ockie Bosch Margaret Kilvington Don Harley and Ian Brown 《Natural resources forum》2001,25(3):225-233
Adaptive, or 'learning by doing', approaches are often advocated as a means of providing increased understanding within natural resource management. However, a number of organisational and social issues need to be resolved if these approaches are to be used successfully. A case study in the South Island high country of New Zealand is used to review what is needed to support an ongoing community-based monitoring and adaptive management programme. First, the case study is described, paying attention to the social context of the resource management problem. The results of a workshop that explored this problem are then outlined, along with a proposed information flow suggested by participants. Requirements for future steps to resolve these problems (such as information protocols and a multi-stakeholder information system) are discussed. Finally, some broad lessons are drawn from this exercise that could help others developing similar approaches. 相似文献
172.
Kate S. Boersma Clifford H. Ryer Thomas P. Hurst Selina S. Heppell 《Behavioral ecology and sociobiology》2008,62(12):1959-1968
Animals balance feeding and anti-predator behaviors at various temporal scales. When risk is infrequent or brief, prey can
postpone feeding in the short term and temporally allocate feeding behavior to less risky periods. If risk is frequent or
lengthy, however, prey must eventually resume feeding to avoid fitness consequences. Species may exhibit different behavioral
strategies, depending on the fitness tradeoffs that exist in their environment or across their life histories. North Pacific
flatfishes that share juvenile rearing habitat exhibit a variety of responses to predation risk, but their response to risk
frequency has not been examined. We observed the feeding and anti-predator behaviors of young-of-the-year English sole (Parophrys vetulus), northern rock sole (Lepidopsetta polyxystra), and Pacific halibut (Hippoglossus stenolepis)—three species that exhibit divergent anti-predator strategies—following exposure to three levels of predation risk: no risk,
infrequent (two exposures/day), and frequent (five exposures/day). The English sole responded to the frequent risk treatment
with higher feeding rates than during infrequent risk, following a pattern of behavioral response that is predicted by the
risk allocation hypothesis; rock sole and halibut did not follow the predicted pattern, but this may be due to the limited
range of treatments. Our observations of unique anti-predator strategies, along with differences in foraging and species-specific
ecologies, suggest divergent trajectories of risk allocation for the three species. 相似文献
173.
Matthiopoulos J Graham K Smout S Asseburg C Redpath S Thirgood S Hudson P Harwood J 《Ecology》2007,88(10):2576-2586
Ecological theory predicts that generalist predators should damp or suppress long-term periodic fluctuations (cycles) in their prey populations and depress their average densities. However, the magnitude of these impacts is likely to vary depending on the availability of alternative prey species and the nature of ecological mechanisms driving the prey cycles. These multispecies effects can be modeled explicitly if parameterized functions relating prey consumption to prey abundance, and realistic population dynamical models for the prey, are available. These requirements are met by the interaction between the Hen Harrier (Circus cyaneus) and three of its prey species in the United Kingdom, the Meadow Pipit (Anthus pratensis), the field vole (Microtus agrestis), and the Red Grouse (Lagopus lagopus scoticus). We used this system to investigate how the availability of alternative prey and the way in which prey dynamics are modeled might affect the behavior of simple trophic networks. We generated cycles in one of the prey species (Red Grouse) in three different ways: through (1) the interaction between grouse density and macroparasites, (2) the interaction between grouse density and male grouse aggressiveness, and (3) a generic, delayed density-dependent mechanism. Our results confirm that generalist predation can damp or suppress grouse cycles, but only when the densities of alternative prey are low. They also demonstrate that diametrically opposite indirect effects between pairs of prey species can occur together in simple systems. In this case, pipits and grouse are apparent competitors, whereas voles and grouse are apparent facilitators. Finally, we found that the quantitative impacts of the predator on prey density differed among the three models of prey dynamics, and these differences were robust to uncertainty in parameter estimation and environmental stochasticity. 相似文献
174.
Curtis A. Brown Wayne J. Graham 《Journal of the American Water Resources Association》1988,24(6):1303-1309
ABSTRACT: To facilitate decisions regarding the need for modification of potentially unsafe dams, the U.S. Bureau of Reclamation developed procedures for assessing the threat to human lives posed by the failure of individual dams. The procedures provide a conceptual model of the variables influencing the loss of life from dam failure and a method for predicting loss of life based on the size of the population at risk from failure and the amount of warning time available for that population. The prediction equations are based on an analysis of 24 dam failures and major flash floods occurring since 1950. Adjustments to the predictions to reflect special local conditions are also discussed. 相似文献
175.
Efforts are accelerating to protect and restore ecosystems globally. With trillions of dollars in ecosystem services at stake, no clear framework exists for developing or prioritizing approaches to restore coral reefs even as efforts and investment opportunities to do so grow worldwide. Restoration may buy time for climate change mitigation, but it lacks rigorous guidance to meet objectives of scalability and effectiveness. Lessons from restoration of terrestrial ecosystems can and should be rapidly adopted for coral reef restoration. We propose how the 10 golden rules of effective forest restoration can be translated to accelerate efforts to restore coral reefs based on established principles of resilience, management, and local stewardship. We summarize steps to undertake reef restoration as a management strategy in the context of the diverse ecosystem service values that coral reefs provide. Outlining a clear blueprint is timely as more stakeholders seek to undertake restoration as the UN Decade on Ecosystem Restoration begins. 相似文献
176.
Biosensors for detection of mercury in contaminated soils 总被引:1,自引:0,他引:1
Bontidean I Mortari A Leth S Brown NL Karlson U Larsen MM Vangronsveld J Corbisier P Csöregi E 《Environmental pollution (Barking, Essex : 1987)》2004,131(2):255-262
Biosensors based on whole bacterial cells and on bacterial heavy metal binding protein were used to determine the mercury concentration in soil. The soil samples were collected in a vegetable garden accidentally contaminated with elemental mercury 25 years earlier. Bioavailable mercury was measured using different sensors: a protein-based biosensor, a whole bacterial cell based biosensor, and a plant sensor, i.e. morphological and biochemical responses in primary leaves and roots of bean seedlings grown in the mercury-contaminated soil. For comparison the total mercury concentration of the soil samples was determined by AAS. Whole bacterial cell and protein-based biosensors gave accurate responses proportional to the total amount of mercury in the soil samples. On the contrary, plant sensors were found to be less useful indicators of soil mercury contamination, as determined by plant biomass, mercury content of primary leaves and enzyme activities. 相似文献
177.
The Landscape Development Intensity index (LDI), which is based on non-renewable energy use and integrates diverse land use
activities, was compared to other measures of LU (e.g., %agriculture, %urban) to determine its ability for predicting benthic
diatom composition in freshwater marshes of peninsular Florida. In this study, 70 small, isolated herbaceous marshes located
along a human disturbance gradient (generally agricultural) throughout peninsular Florida were sampled for benthic diatoms
and soil and water physical/chemical parameters (i.e., TP, TKN, pH, specific conductance, etc.). Landscape measures of percent
agriculture, percent urban, percent natural, and LDI index values were calculated for a 100 m buffer around each site. The
strongest relationships using Mantel's r statistic, which ranges from −1 to 1, were found between benthic diatom composition, the combined soil and water variables,
and LDI scores (r=0.51, P<0.0001). Although similar, soil and water variables alone (r=0.45, P<0.0001) or with percent agriculture or percent natural were not as strongly correlated (both Mantel's r=0.46, P<0.0001). Little urban land use was found in the areas surrounding the study wetlands. Diatom data were clustered using flexible
beta into 2 groups, and stepwise discriminant analysis identified specific conductance, followed by LDI score, soil pH, water
total phosphorus, and ammonia, as cluster-separating variables. The LDI explained slightly more of the variation in species
composition than either percent agriculture or percent natural, perhaps because the LDI can combine disparate land uses into
a single quantitative value. However, the ecological significance of the difference between land use metrics and diatom composition
is controvertible, and additional tests including more varied land uses appear warranted. 相似文献
178.
C A Rowan W M Connolly H S Brown 《Journal of environmental science and health. Part. B》1984,19(7):611-648
Currently, the U.S. Environmental Protection Agency has established air standards for relatively few chemicals. As a result, state agencies are faced with controlling air contaminants for a large number of chemicals posing potential public health threats. Use of occupational standards as a basis for deriving ambient air guidelines is a method used by states to control air toxics. This standard development approach is reviewed by considering the differences in the health basis and numerical values which often occur among the occupational standards set by OSHA, NIOSH and ACGIH. This study indicated that careful selection should be made of the most appropriate occupational standard to use to protect public health. A comparison is made of chemicals regulated by various state air toxic programs using occupational standards lowered by a safety factor to concentrations established by the U.S. EPA. It was found that the air guidelines vary, but the degree of stringency can be comparable. 相似文献
179.
180.
Summary Parental exclusion analyses based on allozyme data were performed on 105 families of cliff swallows (Hirundo pyrrhonota) from southwestern Nebraska, USA. The protein products of seve polymorphic loci were resolved from blood, and at least one parental exclusion occurred at six of these loci. One or both putative parents were excluded for 35 nestlings from 22 different families. The mean number of non-kin nestlings in these families was 1.59. Non-kin nestlings were found in families with brood sizes ranging from two to five. A greater percentage of families in an 1100-nest colony had non-kin offspring than in two smaller colonics, although the difference was not statistically significant. Application of genetic models to these data and the observed distribution of parental exclusions suggested that multiple parentage in cliff swallows results more often from intraspecific brood parasitism than from forced extra-pair copulations. Based on the calculated probabilities of detecting non-kin, we estimate that 23.7% of all nestlings in our population are not the offspring of one or both of their putative parents. We estimate that about 43% of all cliff swallow nests in Nebraska contain at least one offspring resulting from intraspecific brood parasitism, and that about 6% of nests might contain offspring resulting from extra-pair copulations. 相似文献