Seasonal and spatial distribution of metals in surface sediment of an urban estuary

Aquatic pollution by metals is of concern because of various toxic effects to marine life. The Tolka Estuary, Co. Dublin, Ireland, is a typical Irish urban estuary. It has a significant metal loading originating from the urban environment. Results of a 25month analysis of cadmium, copper, lead and zinc spatial and temporal distribution over 10 sample locations in this estuary are presented in this paper. Metal concentrations were analysed using differential pulse polarography. Significant seasonal and spatial trends in metal distribution were observed over the 25months. Sediment metal concentrations gradually increased (30-120%) in spring to a maximum at the end of summer which was followed by a decrease in winter months (30-60%). Sediment organic matter (OM) concentrations exhibited similar seasonal trends and a positive correlation between OM and metal distributions was observed, implying OM had an influence on metal distributions over time.     

Using SWAT to Model Streamflow in Two River Basins With Ground and Satellite Precipitation Data1

Abstract: Both ground rain gauge and remotely sensed precipitation (Next Generation Weather Radar – NEXRAD Stage III) data have been used to support spatially distributed hydrological modeling. This study is unique in that it utilizes and compares the performance of National Weather Service (NWS) rain gauge, NEXRAD Stage III, and Tropical Rainfall Measurement Mission (TRMM) 3B42 (Version 6) data for the hydrological modeling of the Middle Nueces River Watershed in South Texas and Middle Rio Grande Watershed in South Texas and northern Mexico. The hydrologic model chosen for this study is the Soil and Water Assessment Tool (SWAT), which is a comprehensive, physical‐based tool that models watershed hydrology and water quality within stream reaches. Minor adjustments to selected model parameters were applied to make parameter values more realistic based on results from previous studies. In both watersheds, NEXRAD Stage III data yields results with low mass balance error between simulated and actual streamflow (±13%) and high monthly Nash‐Sutcliffe efficiency coefficients (NS > 0.60) for both calibration (July 1, 2003 to December 31, 2006) and validation (2007) periods. In the Middle Rio Grande Watershed NEXRAD Stage III data also yield robust daily results (time averaged over a three‐day period) with NS values of (0.60‐0.88). TRMM 3B42 data generate simulations for the Middle Rio Grande Watershed of variable qualtiy (MBE = +13 to ?16%; NS = 0.38‐0.94; RMSE = 0.07‐0.65), but greatly overestimates streamflow during the calibration period in the Middle Nueces Watershed. During the calibration period use of NWS rain gauge data does not generate acceptable simulations in both watersheds. Significantly, our study is the first to successfully demonstrate the utility of satellite‐estimated precipitation (TRMM 3B42) in supporting hydrologic modeling with SWAT; thereby, potentially extending the realm (between 50°N and 50°S) where remotely sensed precipitation data can support hydrologic modeling outside of regions that have modern, ground‐based radar networks (i.e., much of the third world).     

Volcanic hazard or economic destitution: hard choices in Banños,Ecuador

In 1999, the entire population of tourism-dependent Baños, Ecuador, some 16,000 people, was evacuated in anticipation of a violent eruption of Mount Tungurahua. Subsequently, many areas in the risk zone experienced heavy ash falls, lahars, and landslides, although no cataclysmic events occurred. Many small rural communities were also evacuated. While these communities became impacted by the hazard, Baños avoided most direct effects. Conditions for all evacuees were grim, and their conditions compounded because Ecuador was simultaneously undergoing profound economic and political crises. Absent livelihood alternatives, community leaders from Baños organized a return to their town even though it remained under an evacuation order. An aggressive campaign brought tourists and more residents back and Baños revived economically; however, this was achieved at the cost of hazard awareness among both groups, tourists and residents, and public safety became compromised.     

Evaluation of management effectiveness of protected areas in the Volta Basin,Ghana: perspectives on the methodology for evaluation,protected area financing and community participation

ABSTRACT

Protected areas are widely recognized as an important strategy for biodiversity conservation. Most of the sites are, however, poorly managed as resource exploitation by fringe communities and low government funding, among other things, threaten their management effectiveness. We used the World Commission on Protected Areas framework for designing management effectiveness evaluation systems, with the Rapid Assessment and Prioritization of Protected Areas Management (RAPPAM) methodology as a tool, to evaluate six components of the management cycle at six sites in Ghana for their management effectiveness. We examined the robustness of RAPPAM as an evaluation tool in the African context. The results showed that most of the sites evaluated are vulnerable and exposed to various degrees of pressure and threats, including poverty in the nearby communities, adjacent land-use and encroachment. On RAPPAM, we noted that apart from inconsistencies in some of the assessment scores due to the biases associated with the self-assessment approach of the methodology, the management effectiveness framework places little emphasis on financing and community participation, though both play major roles in the management process. We proposed a modification of the framework within the African context, to address effectively the underlying courses of pressure and threats facing Ghana’s protected areas.     

Economics of ground-water quality monitoring: A survey of experts

The cost of a monitoring program can be easily ascertained in terms of the expenditures incurred for such items as personnel, supplies, field visits, instrumentation and laboratory analyses. The benefits of a monitoring program, however, cannot be easily evaluated due to the diversity of objectives for which monitoring programs are initiated and operated. The case study and the results of the follow-up exploratory survey reported in this paper were intended to capture the objective as well as the subjective reasons employed by a group of experts in responding to selected socio-economic questions related to the design of monitoring programs. Ninety-seven individuals, through a formal questionnaire, participated in the survey. They showed definite preferences, although there was some variability in responses due to such factors as residential status, institutional affiliation, education, and the length of professional experience. It was clear that the respondents favored the inclusion of cost-effectiveness criteria in monitoring programs; were ambivalent to the idea of initiating a regulatory program to monitor the wells of a large number of private owners; and if such a program were to be initiated they recommended that individual well owners share the bulk of the financial burden. Preliminary results from such exploratory surveys can lead to the framing of insightful research questions or hypotheses for further evaluation. Confirmatory testing of such questions or hypotheses in real world settings is a valuable area for further research.     

A simple plant mutation abets a predator-diversity cascade

Resource consumption often increases with greater consumer biodiversity. This could result either from complementarity among consumers or the inclusion of particular key species, and it is often difficult to differentiate between these two mechanisms. We exploited a simple plant mutation (reduced production of surface waxes) to alter foraging within a community of aphid predators, and thus perhaps shift the nature of resulting predator diversity effects. We found that greater predator species richness dramatically increased prey suppression and plant biomass only on mutant, reduced-wax pea plants (Pisum sativum). On pea plants from a sister line with wild type, waxier plant surfaces, predator species richness did not influence predators' impacts on herbivores or plants. Thus, a change in plant surface structure acted to turn on, or off, the cascading effects of predator diversity. Greater predator richness encouraged higher densities of true predators but did not lead to greater reproduction by a parasitoid, Aphidius ervi; fecundity of each natural enemy species was similar for the two plant types. Behavioral observations indicated that although A. ervi was less likely to forage within species-rich predator communities, low-wax plants mitigated this interference by encouraging generally greater A. ervi foraging and thus high rates of aphid dislodgement (aphids dropped from plants to escape A. ervi, but not the other predators). Thus, only species-rich, low-wax plants simultaneously encouraged strong species-specific effects of A. ervi, and strong complementarity among the other predator species. In summary, our study provides evidence that diversity effects in predator assemblages are sensitive to habitat characteristics. Further, we show that a simple plant morphological trait, controlled by a single gene mutation, can dramatically alter the cascading effects of predator species richness on herbivores and plants.     

Historical spatial reconstruction of a spawning‐aggregation fishery

Aggregations of individual animals that form for breeding purposes are a critical ecological process for many species, yet these aggregations are inherently vulnerable to exploitation. Studies of the decline of exploited populations that form breeding aggregations tend to focus on catch rate and thus often overlook reductions in geographic range. We tested the hypothesis that catch rate and site occupancy of exploited fish‐spawning aggregations (FSAs) decline in synchrony over time. We used the Spanish mackerel (Scomberomorus commerson) spawning‐aggregation fishery in the Great Barrier Reef as a case study. Data were compiled from historical newspaper archives, fisher knowledge, and contemporary fishery logbooks to reconstruct catch rates and exploitation trends from the inception of the fishery. Our fine‐scale analysis of catch and effort data spanned 103 years (1911–2013) and revealed a spatial expansion of fishing effort. Effort shifted offshore at a rate of 9.4 nm/decade, and 2.9 newly targeted FSAs were reported/decade. Spatial expansion of effort masked the sequential exploitation, commercial extinction, and loss of 70% of exploited FSAs. After standardizing for improvements in technological innovations, average catch rates declined by 90.5% from 1934 to 2011 (from 119.4 to 11.41 fish/vessel/trip). Mean catch rate of Spanish mackerel and occupancy of exploited mackerel FSAs were not significantly related. Our study revealed a special kind of shifting spatial baseline in which a contraction in exploited FSAs occurred undetected. Knowledge of temporally and spatially explicit information on FSAs can be relevant for the conservation and management of FSA species.     

Integrated Simulation and Modelling Approach to Decision Making and Environmental Protection

This paper's objective is first to test the application of computer simulation and modelling tools in investigating the effects of applying sustainable manufacturing practices in a smelter plant, and second, to prove quantitatively and visually that 'sustainibility is free'. A simulation model is built to test and capture two different operating polices, 'Policy 1' and 'Policy 2', of an industrial system. In the case study, the simulation model is designed to reflect the effects of decision making in the activites found in a smelter plant, and to quantify the cost, sustainable and environmental consequences based on the decisions. Apart from providing a means of accurately measuring a system's performance, the purpose of using simulation tools is also to link the economic factors, such as productivity and total costs, as well as the sustainable factors, such as natural resource and energy consumption of a system. The simulation results prove quantitatively and visually that sustainability is not only 'free' but is, in fact, a far better proposition for economic growth in the medium to longer term than traditional forms of management.