Metal accumulation and performance of nestlings of passerine bird species at an urban brownfield site

The use of passerine species as bioindicators of metal bioaccumulation is often underutilized when examining the wildlife habitat value of polluted sites. In this study we tested feathers of nestlings of two common bird species (house wren and American robin) for accumulation of Pb, Zn, As, Cr, Cu, Fe in comparison of a polluted, urban brownfield with a rural, unpolluted site. House wren nestlings at the study site accumulated significantly greater concentrations of all target metals except Zn. At the polluted site we found significant species differences of metal concentrations in feathers, with house wrens accumulating greater concentrations of Pb, Fe, and Zn but slightly lesser accumulations of Cr and Cu than American robins. Although house wren nestlings demonstrated significant accumulation of metals, these concentrations showed little effect on size metrics or fledge rates during the breeding season compared to nestlings from the control site.     

Ecologically Functional Floodplains: Connectivity,Flow Regime,and Scale1

Opperman, Jeffrey J., Ryan Luster, Bruce A. McKenney, Michael Roberts, and Amanda Wrona Meadows, 2010. Ecologically Functional Floodplains: Connectivity, Flow Regime, and Scale. Journal of the American Water Resources Association (JAWRA) 46(2):211-226. DOI: 10.1111/j.1752-1688.2010.00426.x Abstract: This paper proposes a conceptual model that captures key attributes of ecologically functional floodplains, encompassing three basic elements: (1) hydrologic connectivity between the river and the floodplain, (2) a variable hydrograph that reflects seasonal precipitation patterns and retains a range of both high and low flow events, and (3) sufficient spatial scale to encompass dynamic processes and for floodplain benefits to accrue to a meaningful level. Although floodplains support high levels of biodiversity and some of the most productive ecosystems on Earth, they are also among the most converted and threatened ecosystems and therefore have recently become the focus of conservation and restoration programs across the United States and globally. These efforts seek to conserve or restore complex, highly variable ecosystems and often must simultaneously address both land and water management. Thus, such efforts must overcome considerable scientific, technical, and socioeconomic challenges. In addition to proposing a scientific conceptual model, this paper also includes three case studies that illustrate methods for addressing these technical and socioeconomic challenges within projects that seek to promote ecologically functional floodplains through river-floodplain reconnection and/or restoration of key components of hydrological variability.     

Recovery of Sediment Characteristics in Moraine,Headwater Streams of Northern Minnesota After Forest Harvest1

Merten, Eric C., Nathaniel A. Hemstad, Randall K. Kolka, Raymond M. Newman, Elon S. Verry, and Bruce Vondracek, 2010. Recovery of Sediment Characteristics in Moraine, Headwater Streams of Northern Minnesota After Forest Harvest. Journal of the American Water Resources Association (JAWRA) 46(4): 733-743. DOI: 10.1111/j.1752-1688.2010.00445.x Abstract: We investigated the recovery of sediment characteristics in four moraine, headwater streams in north-central Minnesota after forest harvest. We examined changes in fine sediment levels from 1997 (preharvest) to 2007 (10 years postharvest) at study plots with upland clear felling and riparian thinning, using canopy cover, proportion of unstable banks, surficial fine substrates, residual pool depth, and streambed depth of refusal as response variables. Basin-scale year effects were significant (p < 0.001) for all responses when evaluated by repeated-measures ANOVAs. Throughout the study area, unstable banks increased for several years postharvest, coinciding with an increase in windthrow and fine sediment. Increased unstable banks may have been caused by forest harvest equipment, increased windthrow and exposure of rootwads, or increased discharge and bank scour. Fine sediment in the channels did not recover by summer 2007, even though canopy cover and unstable banks had returned to 1997 levels. After several storm events in fall 2007, 10 years after the initial sediment input, fine sediment was flushed from the channels and returned to 1997 levels. Although our study design did not discern the source of the initial sediment inputs (e.g., forest harvest, road crossings, other natural causes), we have shown that moraine, headwater streams can require an extended period (up to 10 years) and enabling event (e.g., high storm flows) to recover from large inputs of fine sediment.     

Prymnesium parvum: The Texas Experience1

Southard, Gregory M., Loraine T. Fries, and Aaron Barkoh, 2010. Prymnesium parvum: The Texas Experience. Journal of the American Water Resources Association (JAWRA) 46(1):14-23. DOI: 10.1111/j.1752-1688.2009.00387.x Abstract: Golden alga Prymnesium parvum was first identified in Texas during a fish kill investigation on the Pecos River in 1985. Since then golden alga kills occurred sporadically in a variety of waters in the western part of the state until 2001 when the alga became endemic in the Brazos, Canadian, Colorado, Red, and Rio Grande river systems, including the water supplies of two public fish hatcheries, the Possum Kingdom and Dundee state fish hatcheries. The increasing area adversely affected by the alga and frequent massive fish kills heightened public and political awareness and concerns regarding the ecological and economic impacts of P. parvum blooms. The Texas Parks and Wildlife Department (TPWD), the wildlife conservation agency of the state, responded to these concerns with a program to assess the ecological and economic impacts and to develop management options. To date 33 water bodies have been affected and losses are conservatively estimated at 34 million fish valued at US$13 million. Several sport fisheries, including smallmouth bass Micropterus dolomieu, striped bass Morone saxatilis, channel catfish Ictalurus punctatus, and blue catfish Ictalurus furcatus, have been severely affected. Additionally, 26 imperiled fish species occur in the affected water basins and some have been adversely affected. Economic losses associated with reduced fishing and other water-based recreational activities appear considerable. The combined economic losses to three counties (Palo Pinto, Stephens, and Young) surrounding Possum Kingdom reservoir for 2001 and 2003 were estimated at US$2.8 million and US$1.1 million, respectively. This paper describes how the TPWD responded to public and political concerns relative to the emergence of golden alga, its harmful effects to fisheries, and its historic and current statewide distribution.     

Stewardship among lifestyle oriented rural landowners

Changes in landownership associated with amenity migration are affecting the demographic, cadastral and ecological conditions of rural landscapes. These changes and concerns about their impacts on natural resource management, including ecological conservation, relate to both the structural consequences of landownership change, land subdivision and to the motivations, management ability and attitudes of lifestyle oriented rural landowners. Based on an Australian case study near Sydney, NSW, this paper examines the motivations and practices of such landowners, assesses potential consequences for vegetation and characterises the landowners according to three stewardship types.     

林火烈度评价及其空间异质性研究进展

回顾了林火烈度评价的方法,包括单因素评价、综合评价和遥感技术的应用等;综述了林火烈度空间异质性的最新研究进展;展望了林火烈度及其空间异质性研究的未来发展趋势。     

合肥城市绿地系统的景观生态评价

城市绿地作为城市结构中的自然生产力主体,在城市生态系统中起着重要的作用。为科学合理地评价合肥城市绿地系统的景观生态现状,建立较为全面、科学的评价指标体系,运用景观生态学的原理和方法,选取多样性指数、均匀度指数、破碎度指数、分离度指数、分维度指数、连通性指数等8个景观指数对合肥市城市绿地系统的景观格局进行研究和分析。研究结果表明,合肥市城市绿地生态格局总体上较好,绿地率和人均公园绿地面积较高;但也存在绿地分布不均,各种类型相差较大,破碎度较高,多样性程度不高,分形维数指数偏低,绿地景观的自然性和复杂性不够,连通度较低等问题。针对存在的问题,提出了合肥城市绿地景观生态规划的优化建议。研究结果为合肥市城市绿地景观生态系统的规划、设计提供了生态学依据,为“生态园林城市和森林城市”建设提供了理论依据     

Estimation of the environmental risk posed by landfills using chemical, microbiological and ecotoxicological testing of leachates

The leachates from 22 municipal solid waste (MSW) landfill sites in Southern Poland were characterized by evaluation of chemical, microbiological and ecotoxicological parameters. Chemical analyses were mainly focused on the identification of the priority hazardous substances according to Directive on Priority Substances, 2008/105/EC (a daughter directive of the WFD) in leachates. As showed, only five substances (Cd, Hg, hexachlorobutadiene, pentachlorobenzene and PAHs) were detected in the leachates. The compounds tested were absent or present at very low concentrations. Among them, only PAHs were found in all samples in the range from 0.057 to 77.2 μg L⁻¹. The leachates were contaminated with bacteria, including aerobic, psychrophilic and mesophilic bacteria, coliform and fecal coliforms, and spore-forming-bacteria, including Clostridium perfringens, and with filamentous fungi. From the analysis of specific microorganism groups (indicators of environmental pollution by pathogenic or opportunistic pathogenic organisms) it can be concluded that the landfill leachates showed sanitary and epidemiological hazard. In the ecotoxicological study, a battery of tests comprised of 5 bioassays, i.e. Microtox®, Spirotox, Rotoxkit F™, Thamnotoxkit F™ and Daphtoxkit F™ magna was applied. The leachate samples were classified as toxic in 13.6%, highly toxic in 54.6% and very highly toxic in 31.8%. The Spirotox test was the most sensitive bioassay used. The percentage of class weight score was very high - above 60%; these samples could definitely be considered seriously hazardous and acutely toxic to the fauna and microflora.No correlations were found between the toxicity values and chemical parameters. The toxicity of leachate samples cannot be explained by low levels of the priority pollutants. It seems that other kinds of xenobiotics present in the samples at subacute levels gave the high aggregate toxic effect.The chemical, ecotoxicological and microbiological parameters of the landfill leachates should be analyzed together to assess the environmental risk posed by landfill emissions.     

Development of a hybrid microbial fuel cell (MFC) and fuel cell (FC) system for improved cathodic efficiency and sustainability: the M2FC reactor

In an effort to improve the efficiency and sustainability of microbial fuel cell (MFC) technology, a novel MFC reactor, the M2FC, was constructed by combining a ferric-based MFC with a ferrous-based fuel cell (FC). In this M2FC reactor, ferric ion, the catholyte in the MFC component, is regenerated by the FC system with the generation of additional electricity. When the MFC component was operated separately, the electricity generation was maintained for only 98 h due to the depletion of ferric ion in the catholyte. In combination with the fuel cell, however, the production of power was sustained because ferric ion was continually replenished from ferrous ion in the FC component. Moreover, the regeneration process of ferric ion by the FC produced additional energy. The M2FC reactor yielded a power density of up to 2 W m⁻² (or time-averaged value of approximately 650 mW m⁻²), density up to 20 times (or approximately six times based on time-averaged value) higher than the corresponding MFC system.     

Plant communities in relation to flooding and soil contamination in a lowland Rhine River floodplain

Using canonical correspondence analysis (CCA), relationships were investigated between plant species composition and flooding characteristics, heavy metal contamination and soil properties in a lowland floodplain of the Rhine River. Floodplain elevation and yearly average flooding duration turned out to be more important for explaining variation in plant species composition than soil heavy metal contamination. Nevertheless, plant species richness and diversity showed a significant decrease with the level of contamination. As single heavy metal concentrations seemed mostly too low for causing phytotoxic effects in plants, this trend is possibly explained by additive effects of multiple contaminants or by the concomitant influences of contamination and non-chemical stressors like flooding. These results suggest that impacts of soil contamination on plants in floodplains could be larger than expected from mere soil concentrations. In general, these findings emphasize the relevance of analyzing effects of toxic substances in concert with the effects of other relevant stressors.