A minimum data set of water quality parameters to assess and compare treatment efficiency of stormwater facilities

Urban stormwater runoff is often of poor quality, impacting aquatic ecosystems and limiting the use of stormwater runoff for recreational purposes. Several stormwater treatment facilities (STFs) are in operation or at the pilot testing stage, but their efficiencies are neither well documented nor easily compared due to the complex contaminant profile of stormwater and the highly variable runoff hydrograph. On the basis of a review of available data sets on urban stormwater quality and environmental contaminant behavior, we suggest a few carefully selected contaminant parameters (the minimum data set) to be obligatory when assessing and comparing the efficiency of STFs. Consistent use of the minimum data set in all future monitoring schemes for STFs will ensure broad-spectrum testing at low costs and strengthen comparability among facilities. The proposed minimum data set includes: (i) fine fraction of suspended solids (<63 μm), (ii) total concentrations of zinc and copper, (iii) total concentrations of phenanthrene, fluoranthene, and benzo(b,k)fluoranthene, and (iv) total concentrations of phosphorus and nitrogen. Indicator pathogens and other specific contaminants (i.e., chromium, pesticides, phenols) may be added if recreational or certain catchment-scale objectives are to be met. Issues that need further investigation have been identified during the iterative process of developing the minimum data set.     

Approaches to Evaluating Climate Change Impacts on Species: A Guide to Initiating the Adaptation Planning Process

Assessing the impact of climate change on species and associated management objectives is a critical initial step for engaging in the adaptation planning process. Multiple approaches are available. While all possess limitations to their application associated with the uncertainties inherent in the data and models that inform their results, conducting and incorporating impact assessments into the adaptation planning process at least provides some basis for making resource management decisions that are becoming inevitable in the face of rapidly changing climate. Here we provide a non-exhaustive review of long-standing (e.g., species distribution models) and newly developed (e.g., vulnerability indices) methods used to anticipate the response to climate change of individual species as a guide for managers grappling with how to begin the climate change adaptation process. We address the limitations (e.g., uncertainties in climate change projections) associated with these methods, and other considerations for matching appropriate assessment approaches with the management questions and goals. Thorough consideration of the objectives, scope, scale, time frame and available resources for a climate impact assessment allows for informed method selection. With many data sets and tools available on-line, the capacity to undertake and/or benefit from existing species impact assessments is accessible to those engaged in resource management. With some understanding of potential impacts, even if limited, adaptation planning begins to move toward the development of management strategies and targeted actions that may help to sustain functioning ecosystems and their associated services into the future.     

Realizing the Potential of Ecosystem Services: A Framework for Relating Ecological Changes to Economic Benefits

Increasingly government agencies are seeking to quantify the outcomes of proposed policy options in terms of ecosystem service benefits, yet conflicting definitions and ad hoc approaches to measuring ecosystem services have created confusion regarding how to rigorously link ecological change to changes in human well-being. Here, we describe a step-by-step framework for producing ecological models and metrics that can effectively serve an economic-benefits assessment of a proposed change in policy or management. A focus of the framework is developing comparable units of ecosystem goods and services to support decision-making, even if outcomes cannot be monetized. Because the challenges to translating ecological changes to outcomes appropriate for economic analyses are many, we discuss examples that demonstrate practical methods and approaches to overcoming data limitations. The numerous difficult decisions that government agencies must make to fairly use and allocate natural resources provides ample opportunity for interdisciplinary teams of natural and social scientists to improve methods for quantifying changes in ecosystem services and their effects on human well-being. This framework is offered with the intent of promoting the success of such teams as they support managers in evaluating the equivalency of ecosystem service offsets and trades, establishing restoration and preservation priorities, and more generally, in developing environmental policy that effectively balances multiple perspectives.     

Evaluating the importance of demographic connectivity in a marine metapopulation

Recently researchers have gone to great lengths to measure marine metapopulation connectivity via tagging, genetic, and trace-elemental fingerprinting studies. These empirical estimates of larval dispersal are key to assessing the significance of metapopulation connectivity within a demographic context, but the life-history data required to do this are rarely available. To evaluate the demographic consequences of connectivity we constructed seasonal, size-structured metapopulation matrix models for two species of mytilid mussel in San Diego County, California, USA. The self-recruitment and larval exchange terms were produced from a time series of realized connectivities derived from trace-elemental fingerprinting of larval shells during spring and fall from 2003 to 2008. Both species exhibited a strong seasonal pattern of southward movement of recruits in spring and northward movement in fall. Growth and mortality terms were estimated using mark-recapture data from representative sites for each species and subpopulation, and literature estimates of juvenile mortality. Fecundity terms were estimated using county-wide settlement data from 2006-2008; these data reveal peak reproduction and recruitment in fall for Mytilus californianus, and spring for M. galloprovincialis. Elasticity and life-stage simulation analyses were employed to identify the season- and subpopulation-specific vital rates and connectivity terms to which the metapopulation growth rate (lambda) was most sensitive. For both species, metapopulation growth was most sensitive to proportional changes in adult fecundity, survival and growth of juvenile stages, and population connectivity, in order of importance, but relatively insensitive to adult growth or survival. The metapopulation concept was deemed appropriate for both Mytilus species as exchange between the subpopulations was necessary for subpopulation persistence. However, highest metapopulation growth occurred in years when a greater proportion of recruits was retained within the predominant source subpopulation. Despite differences in habitat and planktonic duration, both species exhibited similar overall metapopulation dynamics with respect to key life stages and processes. However, different peak reproductive periods in an environment of seasonal current reversals led to different regional (subpopulation) contributions to metapopulation maintenance; this result emphasizes the importance of connectivity analysis for spatial management of coastal resources.     

Seabird use of discards from a nearshore shrimp fishery in the South Atlantic Bight,USA

Shrimp trawling is common throughout the southeastern and Gulf of Mexico coasts of the USA and is the primary contributor to fisheries discards in these regions. Tens of thousands of nearshore seabirds nest near shrimp trawling grounds in the USA, but to date, there has been no assessment of the relationship between seabirds and shrimp trawlers. We examined the taxonomic composition of bycatch, rate at which seabirds scavenged bycatch, and energy density of discarded bycatch in a nearshore commercial shrimp fishery. Bycatch was primarily comprised of demersal fish that are not typically accessible to the plunge-diving and surface-feeding seabirds that occur in the area. Hence, seabird diets in the region appear to be broadened taxonomically by the availability of discards. Results from discard experiments indicated that 70% of the nearly 5,500 items discarded by hand were scavenged by seabirds and that the fate of a discarded item was most strongly predicted by its taxonomic order. Laughing gulls scavenged the greatest proportion of discards, although brown pelicans were the only species to scavenge more discards than predicted based upon their abundance. Because this is the first such study in the region, it is difficult to ascertain the extent or intensity of the impact that discards have on nearshore seabirds. Nonetheless, our results suggest that it will be difficult for managers to clearly understand fluctuations in local seabird population dynamics without first understanding the extent to which these species rely upon discards. This may be especially problematic in situations where seabird populations are recovering following natural or anthropogenic stressors.     

Non-invasive measurement of carbon monoxide burden in Guatemalan children and adults following wood-fired temazcal (sauna-bath) use

The use of wood-fired steam baths, or temazcales, is a potentially dangerous source of CO exposure in Guatemalan Highland communities where adults and children use them regularly for bathing, relaxation, and healing purposes. Physical characteristics of children predispose them to absorb CO faster than adults, placing them at greater exposure and health risks. Efforts to quantify temazcal exposures across all age groups, however, have been hampered by the limitations in exposure measurement methods. In this pilot study we measured COHb levels in children and adults following use of the temazcal using three field-based, non-invasive CO measurement methods: CO-oximetry, exhaled breath, and by estimation of COHb using micro-environmental concentrations and time diaries. We then performed a brief comparison of methods. Average CO concentrations measured during temazcal use were 661 ± 503 ppm, approximately 10 times the 15 min WHO guideline. Average COHb levels for all participants ranged from 12-14% (max of 30%, min 2%), depending on the method. COHb levels measured in children were not significantly different from adults despite the fact that they spent 66% less time exposed. COHb measured by CO-oximetry and exhaled breath had good agreement, but precision of the former was affected substantially by random instrument error. The version of the field CO-oximeter device used in this pilot could be useful in screening for acute CO exposure events in children but may lack the precision for monitoring the burden from less extreme, but more day-to-day CO exposures (e.g. indoor solid fuel use). In urban settings, health effects in children and adults have been associated with chronic exposure to ambient CO concentrations much lower than measured in this study. Future research should focus on reducing exposure from temazcales through culturally appropriate modifications to their design and practices, and targeted efforts to educate communities on the health risks they pose and actions they can take to reduce this risk.     

The production, use and quality of sewage sludge in Denmark

In Denmark, the production of municipal sewage sludge decreased from approximately 170,000 ton d.m. in 1994 to 140,000 ton d.m. in 2002. The sludge is handled and treated in a number of ways. The quality of Danish sludge has steadily improved since the middle of the 1980s, when the first set of quality criteria for heavy metals was introduced. In 1997, cut-off criteria for the organic pollutants, LAS, DEHP, nonylphenol and PAHs were introduced. Effective control from authorities, voluntary phasing out agreements with industry, improved source identification tools, better handling and after-care methods have in combination with higher waste duties led to a significant reduction in the sludge level of especially cadmium, mercury, chromium, LAS and nonylphenol. The increased quality demand has, nevertheless, also led to a minor reduction in the use of sewage sludge as organic fertiliser on agricultural land.     

Application of processed organic municipal solid waste on agricultural land – a scenario analysis

Source separation, composting and anaerobic digestion, with associated land application, are increasingly being considered as alternative waste management strategies to landfilling and incineration of municipal solid waste (MSW). Environmental life cycle assessments are a useful tool in political decision-making about waste management strategies. However, due to the diversity of processed organic MSW and the situations in which it can be applied, the environmental impacts of land application are very hard to determine by experimental means. In the current study, we used the agroecosystem model Daisy to simulate a range of different scenarios representing different geographical areas, farm and soil types under Danish conditions and legislation. Generally, the application of processed organic MSW resulted in increased emissions compared with the corresponding standard scenarios, but with large differences between scenarios. Emission coefficients for nitrogen leaching to the groundwater ranged from 0.03 to 0.87, while those for nitrogen lost to surface waters through tile drains ranged from 0 to 0.30. Emission coefficients for N₂O formation ranged from 0.013 to 0.022 and for ammonia volatilization from 0.016 to 0.11. These estimates are within reasonable range of observed values under similar conditions. Furthermore, a sensitivity analysis showed that the estimates were not very sensitive to the mineralization dynamics of the processed organic MSW. The results show that agroecosystem models can be powerful tools to estimate the environmental impacts of land application of processed MSW under different conditions. Despite this, agroecosystem models have only been used to a very limited degree for this purpose.     

Bats aloft: variability in echolocation call structure at high altitudes

Bats alter their echolocation in response to changes in ecological and behavioral conditions, but little is known about how they adjust call structure in response to changes in altitude. We examined altitudinal variation in the echolocation of Brazilian free-tailed bats, Tadarida brasiliensis, a species known to fly to altitudes of 3,000 m above the ground. From 50.2 h of recordings, we analyzed 113 high-quality echolocation call sequences recorded from 0 to 862 m above ground level. Bats flying near the ground used shorter, higher-frequency, broader-bandwidth calls compared to bats at higher altitudes, an effect likely due to the greater levels of echo-producing clutter (i.e., vegetation, buildings) found near the ground. When ground-level recordings are excluded, bats continue to shift towards the use of longer-duration, lower-frequency, narrower-bandwidth calls with increasing altitude. We propose that the observed high-altitude changes in call structure are a response to changing acoustic attenuation rates and/or decreasing insect densities at higher altitudes.     

Fluxes of NO3-, NH4+, NO,NO2, and N2O in an Old Danish Beech Forest

The fluxes of the major nitrogen compounds havebeen investigated in many ecosystem studies over the world.However, only in few studies has attention been drawn to theimportance of the fluxes of minor gaseous nitrogen compoundsto complete the nitrogen cycle. In Denmark a detailed study onthe nitrogen cycle in an old beech forest has been implementedin 1997 at Gyrstinge near Sorø, Zealand. The study includesthe fluxes of the gases NO, N₂O and water mediatedtransport of NO₃ ^- and NH₄ ⁺. Measurementsof the fluxes of the gaseous compounds are performed withmicro-meteorological methods (eddy-correlation and gradient)and with chambers. Water mediated fluxes encompass rain,throughfall, stem-flow and leaching from the root zone. Thehydrological model is verified by TDR measurements. The findings show that the total water mediated N input tothe forest floor with throughfall and stemflow was 25.6 kg Nha^-1 yr ^-1, and open field wet deposition withprecipitation was 19.0 kg N ha^-1 yr ^-1. The internalcycling of N in the ecosystem measured as turnover oflitterfall and plant uptake was 100 kg N ha^-1 yr ^-1and 14 kg N ha^-1 yr ^-1, respectively. The fluxes ofthe gaseous N compounds NO and N₂O were of minorimportance for the total N turnover in the forest, NO_xemission being <1 kg N ha^-1 yr ^-1 and N₂Oemission from the soil being 0.5 kg N ha^-1 yr ^-1 withno significant difference between wet and dry soils.Concentrations of NO₃ ^- and NH₄ ⁺ in thesoil solution beneath the rooting zone are very small andconsequently the N leaching is almost negligible. It isconcluded that the nitrogen mass balance of this old beechforest ecosystem mainly is controlled by the input by dry andwet deposition and a large internal N cycle with a fast litterturnover. The nitrogen input tothe forest ecosystem which currently exceeds the critical loadby 5 kg N ha^-1 yr ^-1is mainly accumulated in the soil and no significant nitrateleaching is occurring.