Investigating cumulative effects across ecological scales

Species, habitats, and ecosystems are increasingly exposed to multiple anthropogenic stressors, fueling a rapidly expanding research program to understand the cumulative impacts of these environmental modifications. Since the 1970s, a growing set of methods has been developed through two parallel, sometimes connected, streams of research within the applied and academic realms to assess cumulative effects. Past reviews of cumulative effects assessment (CEA) methods focused on approaches used by practitioners. Academic research has developed several distinct and novel approaches to conducting CEA. Understanding the suite of methods that exist will help practitioners and academics better address various ecological foci (physiological responses, population impacts, ecosystem impacts) and ecological complexities (synergistic effects, impacts across space and time). We reviewed 6 categories of methods (experimental, meta-analysis, single-species modeling, mapping, qualitative modeling, and multispecies modeling) and examined the ability of those methods to address different levels of complexity. We focused on research gaps and emerging priorities. We found that no single method assessed impacts across the 4 ecological foci and 6 ecological complexities considered. We propose that methods can be used in combination to improve understanding such that multimodel inference can provide a suite of comparable outputs, mapping methods can help prioritize localized models or experimental gaps, and future experiments can be paired from the outset with models they will inform.     

那年,那地,那人

爱情在你的心里有多重要?在某一个清闲的下午，有否在心里清点着爱过的人?那年，那地，那人，是否颜面依然?     

A course in Environmental Planning and Management

Summary This paper describes a 13-weeks, third-year course in Environmental Planning and Management developed and taught by the authors. Initiated in 1969, the course consists of a mix of lectures, seminars, workshop/laboratory sessions and field-based projects. The objectives of the course are for students: to become aware of the need for, and the complexities of, environmental management; to be able to criticise constructively work done by environmental agencies and consultants, managers and decision makers; and to learn and apply some of the methods and techniques used in environmental management.Topics covered by the current syllabus are: concepts of resource and environment; constitutional aspects; international law and the environment; Australian and Canadian environmental legislation and agencies; human manipulation of ecosystems; energy subsidies; modification of biogeochemical cycles; population dynamics and cropping; fisheries; national parks and reserves—policies in different countries; international heritage areas; environmental assessment (including impact assessment, land evaluation, land capability and land suitability assessment); and regional, integrated land-use and environmental planning and management. Techniques taught include: field surveys and interviewing; laboratory analysis of selected water quality, sediment and soil parameters including nutrient concentrations, heavy metal and pesticide residues; and for some students, applications of geographic information systems (GIS) technology following preceding GIS courses.A major problem is selecting the most appropriate mix between the social and natural sciences—appropriate, first in terms of students' heterogeneous skills and backgrounds, and second, in terms of understanding the causes of environmental problems and issues, and devising practicable solutions.     

Investigation versus remediation: Perception and reality

Case studies show some eyebrow-raising discrepancies between estimated contamination levels and the actual levels measured at the point of remediation. The three site investigations did not provide nearly enough information for estimating the magnitude of the cleanup effort. Inadequate numbers of samples and improper sampling design and analyses provided an unrepresentative picture of the true site conditions.     

Devolving Residential Energy Efficiency Responsibility to Local Government: the case of HECA

Substantial improvements in residential energy efficiency are required if the UK is to meet its target of reducing CO 2 emissions by 20% between 1990 and 2010. The Home Energy Conservation Act 1995 (HECA) devolves much of the responsibility for this to local authorities, by requiring them to draw up strategies to increase energy efficiency in this sector by 30% in the next 10-15 years. While many authorities have responded positively to the Act, others are struggling, and 25% of HECA reports initially failed to meet the Act's statutory obligations. The Association for the Conservation of Energy (ACE) conducted research to identify barriers faced by local authorities in implementing HECA. They were found to include officers' lack of experience, their lack of time and a lack of support from elected members. Action must be taken to ensure that HECA achieves its potential. The authors suggest that the Act needs to be adequately supported by central legislation, and that devolution of responsibility must be accompanied by some devolution of finances. The authors also recommend that the Act could be used as an example for international replication.     

Differential tolerance to metals among populations of the introduced bryozoan Bugula neritina

Resistance to heavy metals is a potentially important trait for introduced marine organisms, facilitating their successful invasion into disturbed natural communities. We conducted laboratory and field experiments to examine differential resistance to copper (Cu) between two source populations of the introduced bryozoan Bugula neritina, originating from a polluted (Port Kembla Harbour, NSW, Australia) and an unpolluted (Botany Bay, NSW, Australia) environment. A laboratory toxicity test was conducted to test the relative resistance of B. neritina recruits from the two sources, by measuring the attachment success, survival and growth of individuals exposed to a range of Cu concentrations (0, 25, 50 and 100 μg l⁻¹ Cu). Upon completion, reciprocal transplantation of the colonies to the original polluted and unpolluted locations was carried out to assess ongoing survival and growth of colonies in the field. B. neritina colonies originating from the polluted Port Kembla Harbour had increased resistance to Cu relative to populations from an unpolluted part of Botany Bay. There appeared to be a cost associated with increased metal tolerance. In the laboratory, Botany Bay recruits displayed significantly higher growth in control treatments and significantly poorer growth at 100 μg l⁻¹ Cu with respect to Port Kembla Harbour individuals, which showed unusually uniform and low growth irrespective of Cu concentration. No difference in attachment success or post-metamorphic survival was observed between populations. Field transplantation showed copper resistance in Port Kembla Harbour colonies constituted an advantage in polluted but not benign environments. The findings of this study provide evidence of the benefits to invasive species of pollution tolerance and suggest that human disturbance can facilitate the establishment and spread of invasive species in marine systems.     

Feeding habits of the dungeness crab Cancer magister as determined by the index of relative importance

Specimens of the Dungeness crab Cancer magister, were collected subtidally and intertidally from an estuary in Washington State, USA in June and September 1980, and January, April, May and July, 1981. Gut contens of freshly collected crabs were analyzed by the Index of Relative Importance; for each prey taxon, this method measured frequency of occurrence, percentage of total biomass, and percentage of total numbers consumed. The most important higher taxon eaten was fish; however, the most important prey genus was the shrimp Crangon spp. There was greater predation on Crangon spp. at night at the intertidal site, and during winter and spring when the shrimp were most abundant there. Feeding activity, as indicated by a weight-specific gut-fullness index, showed no consistent diel pattern. There were significant ontogenetic changes in feeding patterns: first-year crabs preyed primarily on very small bivalves or small crustaceans including their conspecifics; second-year crabs preferred Crangon spp. and fish, and third-year crabs preyed less on Crangon spp. and more on fish. Such changes in feeding habits with ege could be purely due to mechanics of food handling, but might also reduce competition among age groups of crabs, possibly partitioning resources within the estuary. Findings are discussed in terms of optimal foraging and compared to other similar studies.Contribution No. 599, School of Fisheries, University of Washington, Seattle, Washington 98195, USA     

Microbial reduction of sulfate injected to gas condensate plumes in cold groundwater

Despite a rapid expansion over the past decade in the reliance on intrinsic bioremediation to remediate petroleum hydrocarbon plumes in groundwater, significant research gaps remain. Although it has been demonstrated that bacterial sulfate reduction can be a key electron accepting process in many petroleum plumes, little is known about the rate of this reduction process in plumes derived from crude oil and gas condensates at cold-climate sites (mean temperature <10 degrees C), and in complex hydrogeological settings such as silt/clay aquitards. In this field study, sulfate was injected into groundwater contaminated by gas condensate plumes at two petroleum sites in Alberta, Canada to enhance in-situ bioremediation. In both cases the groundwater near the water table had low temperature (6-9 degrees C). Monitoring data had provided strong evidence that bacterial sulfate reduction was a key terminal electron accepting process (TEAP) in the natural attenuation of dissolved hydrocarbons at these sites. At each site, water with approximately 2000 mg/L sulfate and a bromide tracer was injected into a low-sulfate zone within a condensate-contaminant plume. Monitoring data collected over several months yielded conservative estimates for sulfate reduction rates based on zero-order kinetics (4-6 mg/L per day) or first-order kinetics (0.003 and 0.01 day(-1)). These results favor the applicability of in-situ bioremediation techniques in this region, under natural conditions or with enhancement via sulfate injection.     

Devolving Residential Energy Efficiency Responsibility to Local Government: The case of HECA

Substantial improvements in residential energy efficiency are required if the UK is to meet its target of reducing CO 2 emissions by 20% between 1990 and 2010. The Home Energy Conservation Act 1995 (HECA) devolves much of the responsibility for this to local authorities, by requiring them to draw up strategies to increase energy efficiency in this sector by 30% in the next 10-15 years. While many authorities have responded positively to the Act, others are struggling, and 25% of HECA reports initially failed to meet the Act's statutory obligations. The Association for the Conservation of Energy (ACE) conducted research to identify barriers faced by local authorities in implementing HECA. They were found to include officers' lack of experience, their lack of time and a lack of support from elected members. Action must be taken to ensure that HECA achieves its potential. The authors suggest that the Act needs to be adequately supported by central legislation, and that devolution of responsibility must be accompanied by some devolution of finances. The authors also recommend that the Act could be used as an example for international replication.     

Group leadership depends on energetic state in a nomadic collective foraging caterpillar

Group living is a common strategy among animals and has arisen independently in over 300 species of Lepidoptera. Yet, activity synchrony between individuals is necessary to derive the benefits that ensue from an aggregated lifestyle. Which individuals decide which activities to perform and when to perform them is, therefore, a fundamental question. In some species of social caterpillars and sawflies, the role of a potential behavioral polyethism between individuals has been suggested, whereby certain individuals are consistently more likely to initiate and lead a foraging event. However, in these cases, evidence in support of division of labor is lacking. This study was undertaken to determine if certain individuals of Malacosoma disstria are more likely to be consistent group leaders or if transient leaders could be predicted by the differences in energetic states between individuals. The results of this study indicate that unfed caterpillars initiate foraging bouts and are more likely to lead locomotion. There was no size or sex-based bias in those individuals that acted as temporary leaders. Consistent behavioral differences between individuals, if they exist, are therefore not necessary to explain task allocation and synchronization during foraging in this species.