Incorporating known sources of uncertainty to determine precautionary harvests of saltwater crocodiles.

It has been demonstrated repeatedly that the degree to which regulation operates and the magnitude of environmental variation in an exploited population will together dictate the type of sustainable harvest achievable. Yet typically, harvest models fail to incorporate uncertainty in the underlying dynamics of the target population by assuming a particular (unknown) form of endogenous control. We use a novel approach to estimate the sustainable yield of saltwater crocodile (Crocodylus porosus) populations from major river systems in the Northern Territory, Australia, as an example of a system with high uncertainty. We used multimodel inference to incorporate three levels of uncertainty in yield estimation: (1) uncertainty in the choice of the underlying model(s) used to describe population dynamics, (2) the error associated with the precision and bias of model parameter estimation, and (3) environmental fluctuation (process error). We demonstrate varying strength of evidence for density regulation (1.3-96.7%) for crocodiles among 19 river systems by applying a continuum of five dynamical models (density-independent with and without drift and three alternative density-dependent models) to time series of density estimates. Evidence for density dependence increased with the number of yearly transitions over which each river system was monitored. Deterministic proportional maximum sustainable yield (PMSY) models varied widely among river systems (0.042-0.611), and there was strong evidence for an increasing PMSY as support for density dependence rose. However, there was also a large discrepancy between PMSY values and those produced by the full stochastic simulation projection incorporating all forms of uncertainty, which can be explained by the contribution of process error to estimates of sustainable harvest. We also determined that a fixed-quota harvest strategy (up to 0.2K, where K is the carrying capacity) reduces population size much more rapidly than proportional harvest (the latter strategy requiring temporal monitoring of population size to adjust harvest quotas) and greatly inflates the risk of resource depletion. Using an iconic species recovering from recent extreme overexploitation to examine the potential for renewed sustainable harvest, we have demonstrated that incorporating major forms of uncertainty into a single quantitative framework provides a robust approach to modeling the dynamics of exploited populations.     

Towards a framework to assess,compare and develop monitoring and evaluation of climate change adaptation in Europe

Adaptation is increasingly recognised as essential when dealing with the adverse impacts of climate change on societies, economies and the environment. However, there is insufficient information about the effectiveness of adaption policies, measures and actions. For this reason, the establishment of monitoring programmes is considered to be necessary. Such programmes can contribute to knowledge, learning and data to support adaptation governance. In the European Union (EU), member states are encouraged to develop National Adaptation Strategies (NASs). The NASs developed so far vary widely because of differing views, approaches and policies. A number of member states have progressed to monitoring and evaluating the implementation of their NAS. It is possible to identify key elements in these monitoring programmes that can inform the wider policy learning process. In this paper, four generic building blocks for creating a monitoring and evaluation programme are proposed: (1) definition of the system of interest, (2) selection of a set of indicators, (3) identification of the organisations responsible for monitoring and (4) definition of monitoring and evaluation procedures. The monitoring programmes for NAS in three member states—Finland, the UK and Germany—were analysed to show how these elements have been used in practice, taking into account their specific contexts. It is asserted that the provision of a common framework incorporating these elements will help other member states and organisations within them in setting up and improving their adaptation monitoring programmes.     

SELECTED CHALLENGES IN RUNOFF GENERATION RESEARCH IN FORESTS FROM THE HILLSLOPE TO HEADWATER DRAINAGE BASIN SCALE1

ABSTRACT: When faced with practical forest land management issues such as the impacts of logging or forest conversion to other land uses, planners ideally require a comprehensive understanding of within drainage basin hydrological processes to determine the most vulnerable areas to increased storm runoff and erosion. Land managers in particular need to know the source areas and magnitude of inputs to the storm hydrograph, in terms of water quantity, sediment and solute transport; and the routing of such hydrographs from headwater to larger drainage basins. The latter includes an overall assessment at various scales of the impacts of forest disturbance and conversion on the water balance. This paper will focus on runoff generation in terms of identifying the various pathways and source areas. Such aspects will be linked with the need for a more comprehensive effort towards the field testing of so-called ‘physically based’ models of runoff generation. Some of the controversial issues arising from the difficulties in reconciling results from hydrochemical investigations with complementary hydrometric studies will be highlighted. Subsequently, attention will be given to topographic-wetness models, which have promising applications in forestland management. In addition, alternative simple models for application at the catchment scale will be assessed. The latter is in recognition that at smaller scales, heterogeneity both in time and space of soil hydraulic properties demand a greater number of parameters in modelling. Such considerations can even prove an obstacle in terms of the confident application of ‘physically based’ models.     

Using earth observation data from multiple sources to map rare habitats in a coastal conservation area

Kenfig NNR (National Nature Reserve) is a coastal sand dune system in south Wales, UK. The site is an important location for the conservation of the fen orchidLiparis loeselii, a significant proportion of the UK population is found solely on the site. Approaches to the mapping and monitoring of the habitats at Kenfig NNR using EO (Earth Observation) methods are investigated. Typical airborne EO missions over such sites produce more than a single source of EO data; these may include various optical imaging sensors with different spectral ranges, film cameras and ranging devices to measure topography. Conservation managers are thus presented with the problem of which sources of data to use when producing a land cover map of the site of interest. Using a data set gathered over the Kenfig NNR site, we investigate land cover mapping methods for conservation. The land cover types of interest typically cover small areas within a much larger site so they present a hard problem for the EO data and associated classification methods to solve. Land cover classifications produced from the data sets provide a set of competing hypotheses of land cover type for the site. Methods we use to resolve this competition between the data sets include voting methods, data fusion methods and a method utilising fuzzy logic to aggregate information. This paper is intended to act as an introduction to some of the issues involved in using EO data for habitat mapping in highly heterogeneous coastal dune environments and to present some preliminary results of the performance of each method.     

Assessing the efficacy of dredged materials from lake panasoffkee,florida: Implication to environment and agriculture part 1: Soil and environmental quality aspect

BACKGROUND, AIMS AND SCOPE: Dredged materials because of its variable but unique physical and chemical properties are often viewed by society and regulators as pollutants, but many have used these materials in coastal nourishment, land or wetland creation, construction materials, and for soil improvement as a soil amendment. Environmental impact assessment is an important pre-requisite to many dredging initiatives. The ability to reuse lake-dredge materials (LDM) for agricultural purposes is important because it reduces the need for off-shore disposal and provides an alternative to disposal of the materials in landfills. Additional research on disposal options of dredged materials are much needed to supply information on criteria testing and evaluation of the physical and chemical impacts of dredged materials at a disposal site, as well as information on many other aspects of dredging and dredged material disposal. While preliminary efforts are underway to provide information to establish criteria for land disposal, testing procedures for possible land disposal of contaminated sediments are still in their developing stage. The objective of this study (Part 1) was to quantify the effect of applied LDM from Lake Panasoffkee (LP), Florida on soil physico-chemical properties (soil quality) at the disposal site. This series of two papers aims at providing assessment of the efficacy of lake-dredged materials from LP especially its implication to environment (soil quality, Part 1) and agriculture (forage quality and pasture establishment, Part 2). METHODS: The experimental treatments that were evaluated consisted of different ratios of natural soil (NS) to LDM: LDM0 (100% NS:0% LDM); LDM25 (75% NS:25% LDM); LDM50 (50% NS:50% LDM); LDM75 (25% NS:75% LDM); and LDM100 (0% NS:100% LDM). Field layout was based on the principle of a completely randomized block design with four replications. The Mehlich 1 method (0.05 N HCl in 0.025 N H2SO4) was used for chemical extraction of soil. Soil P and other exchangeable cations (Ca, Mg, K, Al, and Fe) were analyzed using an Inductively Coupled Plasma (ICP) Spectroscopy. The effects of dredged materials addition on soil quality and compaction were analyzed statistically following the PROC ANOVA procedures. RESULTS AND DISCUSSION: Sediments that were dredged from LP have high CaCO3 content (82%) and when these materials were incorporated into existing topsoil they would have the same favorable effects as liming the field. Thus, sediments with high CaCO3 may improve the physical and chemical conditions of subtropical sandy pastures. The heavy and trace metal contents of LDM were below the probable effect levels (PEL) and threshold effect levels (TEL). Average values for Pb, Zn, As, Cu, Hg, Se, Cd, and Ni of 5.2 +/- 1.3, 7.0 +/- 0.6, 4.4 +/- 0.1, 8.7 +/- 1.2, 0.01 +/- 0.02, 0.02 +/- 0.02, 2.5 +/- 0.1, and 14.6 +/- 6.4 mg kg(-1), respectively, were below the TEL and the PEL. TEL represents the concentrations of sediment-associated contaminants that are considered to cause significant hazards to aquatic organisms, while, PEL represents the lower limit of the range of the contaminant concentrations that are usually or always associated with adverse biological effects. As such, the agricultural or livestock industry could utilize these LDM to produce forages. LDM should be regarded as a beneficial resource, as a part of the ecological system. Addition of LDM had significant (p < or = 0.001) effects on soil physico-chemical properties and soil quality. Compared with the control plots, the soils in plots amended with LDM exhibited: (1) lower degree of soil compaction; (2) an increase in soil pH, Ca, and Mg; (3) decrease in the levels of soil Mn, Cu, Fe, Zn, and Si; and (4) no significant change in the level of Na in the soil. Results have shown the favorable influence that LDM had on soil compaction. The treatment x year interaction effect was not significant, but the average soil compaction varied widely (p < or = 0.001) with LDM application. In 2002 and 2003, soil compaction of plots was lowered significantly as a result of LDM additions. The least compacted soils in 2002 and 2003 were observed from plots with LDM75 with mean soil compaction of 300 x 10(3) and 350 x 10(3) Pa, respectively. CONCLUSION: Beneficial uses of dredged materials from LP, Florida are both economical and environmental. Often these materials can be obtained at little or no cost to the farmers or landowners in south Florida. Environmentally, dredging of sediments that are rich in CaCO3 should restore the 19.4-sq km LP by removing natural sediments from the lake bottom to improve the fishery, water quality, and navigation of the lake. The bottom sediment materials from lakes, river, and navigational channels usually are composed of upland soil enriched with nutrients and organic matter. These materials should be regarded as a beneficial resource to be used productively and not to be discarded as spoil materials. RECOMMENDATION AND OUTLOOK: Land application of LDM from LP may not only provide substantial benefits that will enhance the environment, community, and society in south Florida, but also in other parts of the world especially those areas having tropical and subtropical climate with forage-based beef cattle pastures. The heavy and trace metal contents of LDM from LP were below the PEL and TEL. As such, the agricultural or livestock industry could utilize these LDM to produce forages (Part 2 of this study). LDM should be regarded as a beneficial resource, as a part of the ecological system. Further studies are still needed to determine whether the environmental and ecological implications of LDM application are satisfied over the longer term.     

Suitability of altai wildrye (Elymus angustus) and slender wheatgrass (Agropyron trachycaulum) for initial reclamation of saline composite tailings of oil sands

The reclamation of freshly produced composite or consolidated tailings (CT) is a challenge for the Oil Sands Industry in the boreal forest of Western Canada. CT tailings materials are characterized by a relatively high salinity (dominated by sodium, sulphate and chloride) and a high pH (8-9). A greenhouse study was conducted to determine the germination, survival, injury and early plant growth of two grass species recommended for land reclamation, altai wildrye (Elymus angustus Trin) and slender wheatgrass (Agropyron trachycaulum Link Malte), growing in two different oil sand CT tailings (alum-CT and gypsum-CT), with and without peat amendment. Ion accumulation in the resulting plant tissues was determined. Our results showed that slender wheatgrass was most affected by the tailings at the germination stage, while for altai wildrye, the early growth stage was the most sensitive stage. Alum-CT had similar or less negative impact on plants than gypsum-CT. Amendment of CT with peat limited the reduction in germination and growth that was recorded in plants growing directly in CT. Based on these results, recommendations were made to improve reclamation strategies.     

Filtration and transport of Bacillus subtilis spores and the F-RNA phage MS2 in a coarse alluvial gravel aquifer: implications in the estimation of setback distances

Filtration of Bacillus subtilis spores and the F-RNA phage MS2 (MS2) on a field scale in a coarse alluvial gravel aquifer was evaluated from the authors' previously published data. An advection-dispersion model that is coupled with first-order attachment kinetics was used in this study to interpret microbial concentration vs. time breakthrough curves (BTC) at sampling wells. Based on attachment rates (katt) that were determined by applying the model to the breakthrough data, filter factors (f) were calculated and compared with f values estimated from the slopes of log (cmax/co) vs. distance plots. These two independent approaches resulted in nearly identical filter factors, suggesting that both approaches are useful in determining reductions in microbial concentrations over transport distance. Applying the graphic approach to analyse spatial data, we have also estimated the f values for different aquifers using information provided by some other published field studies. The results show that values of f, in units of log (cmax/co) m(-1), are consistently in the order of 10(-2) for clean coarse gravel aquifers, 10(-3) for contaminated coarse gravel aquifers, and generally 10(-1) for sandy fine gravel aquifers and river and coastal sand aquifers. For each aquifer category, the f values for bacteriophages and bacteria are in the same order-of-magnitude. The f values estimated in this study indicate that for every one-log reduction in microbial concentration in groundwater, it requires a few tens of meters of travel in clean coarse gravel aquifers, but a few hundreds of meters in contaminated coarse gravel aquifers. In contrast, a one-log reduction generally only requires a few meters of travel in sandy fine gravel aquifers and sand aquifers. Considering the highest concentration in human effluent is in the order of 10(4) pfu/l for enteroviruses and 10(6) cfu/100 ml for faecal coliform bacteria, a 7-log reduction in microbial concentration would comply with the drinking water standards for the downgradient wells under natural gradient conditions. Based on the results of this study, a 7-log reduction would require 125-280 m travel in clean coarse gravel aquifers, 1.7-3.9 km travel in contaminated coarse gravel aquifers, 33-61 m travel in clean sandy fine gravel aquifers, 33-129 m travel in contaminated sandy fine gravel aquifers, and 37-44 m travel in contaminated river and coastal sand aquifers. These recommended setback distances are for a worst-case scenario, assuming direct discharge of raw effluent into the saturated zone of an aquifer. Filtration theory was applied to calculate collision efficiency (alpha) from model-derived attachment rates (katt), and the results are compared with those reported in the literature. The calculated alpha values vary by two orders-of-magnitude, depending on whether collision efficiency is estimated from the effective particle size (d10) or the mean particle size (d50). Collision efficiency values for MS-2 are similar to those previously reported in the literature (e.g. ) [DeBorde, D.C., Woessner, W.W., Kiley, QT., Ball, P., 1999. Rapid transport of viruses in a floodplain aquifer. Water Res. 33 (10), 2229-2238]. However, the collision efficiency values calculated for Bacillus subtilis spores were unrealistic, suggesting that filtration theory is not appropriate for theoretically estimating filtration capacity for poorly sorted coarse gravel aquifer media. This is not surprising, as filtration theory was developed for uniform sand filters and does not consider particle size distribution. Thus, we do not recommend the use of filtration theory to estimate the filter factor or setback distances. Either of the methods applied in this work (BTC or concentration vs. distance analyses), which takes into account aquifer heterogeneities and site-specific conditions, appear to be most useful in determining filter factors and setback distances.     

Shade and flow effects on ammonia retention in macrophyte-rich streams: implications for water quality

Controlled releases of NH4-N and conservative tracers (Br- and Cl-) to five reaches of four streams with contrasting macrophyte communities have shown differing retentions, largely as a result of the way plants interact with stream flow and velocity. First-order constants (k) were 1.0-4.8 d(-1) and retention of NH4-N was 6-71% of amounts added to each reach. Distance travelled before a 50% reduction in concentration was achieved were 40-450 m in three streams under low-flow conditions, and 2400-3800 m at higher flows. Retention (%) of NH4-N can be approximated by a simple function of travel time and k, highlighting the importance of the relationship between macrophytes and stream velocity on nutrient processing. This finding has significant management implications, particularly with respect to restoration of riparian shade. Small streams with predominantly marginal emergent plants are likely to have improved retention of NH4-N as a result of shading or other means of reducing plant biomass. Streams dominated by submerged macrophytes will have impaired NH4-N retention if plant biomass is reduced because of reduced contact times between NH4-N molecules and reactive sites. In these conditions water resource managers should utilise riparian shading in concert with unshaded vegetated reaches to achieve a balance between enhanced in-stream habitat and nutrient processing capacity.     

使用安捷伦科技6890/5973 Inert气相色谱/质谱联用系统全扫描检测低含量多环芳烃

多环芳烃的分析目前仍然是一项具有挑战性的任务,因为多环芳烃会吸附在色谱系统的表面上,因而造成校准时出现非线性,对低含量多环芳烃必需使用选择性离子检测.安捷伦科技公司的6890/5973 inert气相色谱/质谱联用系统就是为了改进分析低含量多环芳烃而设计的,使用全扫描检测时在整个校准范围内呈线性.