A Modeling System to Assess Land Cover Land Use Change Effects on SAV Habitat in the Mobile Bay Estuary

Estuarine ecosystems are largely influenced by watersheds directly connected to them. In the Mobile Bay, Alabama watersheds we examined the effect of land cover and land use (LCLU) changes on discharge rate, water properties, and submerged aquatic vegetation, including freshwater macrophytes and seagrasses, throughout the estuary. LCLU scenarios from 1948, 1992, 2001, and 2030 were used to influence watershed and hydrodynamic models and evaluate the impact of LCLU change on shallow aquatic ecosystems. Overall, our modeling results found that LCLU changes increased freshwater flows into Mobile Bay altering temperature, salinity, and total suspended sediments (TSS). Increased urban land uses coupled with decreased agricultural/pasture lands reduced TSS in the water column. However, increased urbanization or agricultural/pasture land coupled with decreased forest land resulted in higher TSS concentrations. Higher sediment loads were usually strongly correlated with higher TSS levels, except in areas where a large extent of wetlands retained sediment discharged during rainfall events. The modeling results indicated improved water clarity in the shallow aquatic regions of Mississippi Sound and degraded water clarity in the Wolf Bay estuary. This integrated modeling approach will provide new knowledge and tools for coastal resource managers to manage shallow aquatic habitats that provide critical ecosystem services.     

Water distribution system failure: a framework for forensic analysis

The main purpose of a water distribution system (WDS) is to deliver safe water of desirable quality, quantity and continuity to consumers. However, in many cases, a WDS fails to fulfill its goal owing to structural and associated hydraulic failures and/or water quality failures. The impact of these failures can be reduced significantly if preventive actions are taken based on their potential of occurrences or if a failure occurs and is detected within a minimum period of time after its occurrence. The aim of this research was to develop a forensic system for WDS failures. As part of the proposed forensic analysis, a framework has been developed, which investigates structural and associated hydraulic failures as well as water quality failures and integrates all failure investigation under a single platform. Under this framework, four different models have been developed to evaluate and identify structural and associated hydraulic failures and water quality failures. If a failure is detected in the system, the framework is capable of identifying the most probable location of the failure. To investigate the effectiveness of the proposed framework, the developed models have been tested and implemented in different WDSs.     

Adapting to change: transitions in traditional rangeland management of Tibetan yak herders in northwest Yunnan

Tibetan yak herding practices in northwest Yunnan, southwest China have maintained remarkable biological diversity. To learn more about local cultural adaptation to policy changes, we interviewed 37 households in Deqin County on their traditional knowledge, and the changes they have observed in ecological conditions, livestock health, and land management. These villages varied in proximity to main roads, farmland quality, and livelihood options. Herd sizes in Deqin have quadrupled since the 1950s, due to commune era policies and subsequent privatization of livestock. The practice of burning shrubs increased during the communal period but has since decreased due to a burn ban. Herders report that the increase in shrublands invading alpine meadows has reduced livestock forage, reducing the productivity of alpine rangelands and yak health. Butter production has declined by 30 % over the last two decades. Herders are shifting to diversify sources of income when available, but villagers in remote and protected areas continue to depend on livestock for much of their livelihood. Scientific data confirm herder reported ecological changes including increased temperature, decreased snowfall, and accounts of increased erosion (which deserves further study). Climate, policy, and economic incentives have interacted to increase pressure on shrinking alpine meadows and reduce dairy production.     

Modeling spatial patterns in fisheries bycatch: improving bycatch maps to aid fisheries management.

Fisheries bycatch, or incidental take, of large vertebrates such as sea turtles, seabirds, and marine mammals, is a pressing conservation and fisheries management issue. Identifying spatial patterns of bycatch is an important element in managing and mitigating bycatch occurrences. Because bycatch of these taxa involves rare events and fishing effort is highly variable in space and time, maps of raw bycatch rates (the ratio of bycatch to fishing effort) can be misleading. Here we show how mapping bycatch can be enhanced through the use of Bayesian hierarchical spatial models. We compare model-based estimates of bycatch rates to raw rates. The model-based estimates were more precise and fit the data well. Using these results, we demonstrate the utility of this approach for providing information to managers on bycatch probabilities and cross-taxa bycatch comparisons. To illustrate this approach, we present an analysis of bycatch data from the U.S. gill net fishery for groundfish in the northwest Atlantic. The goals of this analysis are to produce more reliable estimates of bycatch rates, assess similarity of spatial patterns between taxa, and identify areas of elevated risk of bycatch.     

PERCOLATION OF LEAD(II) AND CADMIUM(II) THROUGH TWO BENTONITES USED AS LANDFILL LINER

In order to prevent contamination of subsoil and groundwater by leachates containing heavy metals, montmorillonite linings are used on landfill bottoms. It is therefore important to understand ion uptake by this clay. In this study we have performed percolation of lead(II) and cadmium(II) through columns filled firstly with a technical bentonite and then with a reference bentonite. Elution curves provide an evaluation of metals retention. After the percolation step, columns are cut and metal ions are extracted to evaluate influence of side effects and soil depth on metal uptake. Moreover retentions of lead(II) and cadmium(II) are compared.     

Brownfields as a tool for the rejuvenation of land and community

Brownfields have been a powerful force attempting to advance both sustainability and economic development. The author, principally using U.S. examples, advances the belief that the true benefits potentially offered by Brownfields can only be fully realized by using tools such as found in the application of Community Benefit Agreements. In a similar way use of Community-Based Participatory Research frameworks holds out similar promise. The proof of this promise will only be found in the implementation of these models.