Degradation Of Aquatic Ecosystems Research Articles

Removal of intensive agriculture from the landscape improves aquatic ecosystem health

The 20th century witnessed substantial increases in the intensity of agricultural land management. Increased agricultural intensity leads to degradation of aquatic ecosystems. Removal of intensive agriculture from the landscape is rare; however this occurred in the Ovens Valley, Victoria, Australia when its 150-year-old tobacco industry was closed in 2006. The present study examined stress in aquatic biota in the Ovens River and associated wetlands and dams before (1988–89) and after (2010) the tobacco closure. The endpoint observed was incidence of morphological deformities in chironomid (“non-biting midge”) larvae. A significant reduction in deformity incidence, particularly in the mentum (teeth), was observed in larvae collected from waters near or adjacent to tobacco cultivation, between 1988/89 and 2010. Similarly, there is a significant decline in the incidence of deformities in the pecten epipharyngis between 1988/89 and 2010. Ninety-six pesticides were also measured in sediments in 2010, of which only the persistent organochlorines DDT, DDE, DDD and dieldrin were detected. Some analysis of pesticides in sediments was conducted in 1988 but the results were inconclusive because the detection limits were inadequate and not all pesticides being used in tobacco cultivation at that time were analysed. The decline in morphological deformities correlates with the cessation of tobacco cultivation and indicates a recovery in ecosystem health.

Impacts of entrainment and impingement on fish populations: A review of the scientific evidence

In 1972, the United States Congress enacted §316(b) the Clean Water Act, which mandates minimization of the adverse impacts of entrainment and impingement of fish and other aquatic life at cooling water intake structures. Since the Act was passed, there has been continuous controversy over the magnitude of any such impacts and over the need for mitigating measures to reduce these impacts. The objective of this paper is to examine the published scientific information relevant to this issue The review includes (1) peer-reviewed literature reporting results of studies of impacts of entrainment and impingement at power plants on fish populations, (2) peer-reviewed literature and “blue-ribbon” commission reports on aquatic resource degradation that evaluate causes of observed degradation of aquatic ecosystems, and (3) EPA's own assessments of causes of degradation in coastal environments. The clear conclusion from the review is that any impacts caused by impingement and entrainment are small compared to other impacts on fish populations and communities, including overfishing, habitat destruction, pollution, and invasive species. The available scientific evidence does not support a conclusion that reducing entrainment and impingement mortality via regulation of cooling water intakes will result in measurable improvements in recreational or commercial fish populations.

Perspectives on an ecosystem approach to ecogenic challenges in the Great Laurentian Basin and beyond

During the past three centuries in North America, the science and practice of fisheries emerged pragmatically based on experiences of Native Peoples and on practices imported by invading Europeans. Achieving sustainability of high-value harvests became progressively more difficult with expansion of harvesting to low value fish and intensification of other cultural stresses that undercut natural production of the valued species. The history of fisheries has parallels in trapping, forestry, agriculture and other features of ‘development’ including disposal of wastes of all kinds. Further, adverse consequences of ‘conventional progress’ in one sector spilled over to undercut benefits in others. Features of an heuristic mindscape termed ‘ecogeny’, within which to address sustainability in evolving natural/cultural complexes, may be as old as human history. An ecogenic mindscape subsumes implicitly-shared conceptual and practical traditions in ecology, economics, ekistics, ecosophy and other eco-studies. Here ‘eco’ refers to a natural/cultural complex as a holonistic reality, both part and whole. Experimentation, reductionist analyses and quantitative models play important, but not sufficient, roles in this evolving understanding. Here I have situated my personal account, some eight decades long, within this emerging ecogenic mindscape as focused initially on fish and fisheries in the Laurentian Great Lakes Basin. Our lives are complex happenings, with events that cannot be forced into a linear spatio-temporal narrative. With many others, I participated in collaborative networks that addressed major issues in trans-cultural/trans-jurisdictional settings, each at several nested levels of ecogenic organization from local to global: identifying and correcting bad fishing and environmental practices to achieve sustainable high-value fisheries; diagnosing causes of observed degradation of aquatic ecosystems in order to suppress harmful, interacting stresses and achieve rehabilitation; strengthening earlier collaborative governance traditions among fishers and regulators; and assessing likely effects of climate warming on cold-blooded fish in their warming and otherwise stressed habitats. Large culturally-modified natural processes (sun, wind, rain) generate vast amounts of valued goods; but other culturally-modified natural processes (fire, flood, drought) also generate vast harm. Any manifestation of such goods and harms transcends the spatial boundaries of any particular private property or governmental jurisdiction. With just governance of good and/or bad ecogenic realities, both altruistic and selfish commitments need to be exercised fairly. Our networks’ policy goals were ecosystem integrity, sustainable use, just governance and caring stewardship, again at spatial levels of ecogenic organization from local to global. With ethical discourse, we engaged in adaptive co-management initiatives with iterative participation by scientific researchers, experts in computing, traditional knowledge stewards, resource harvesters, environmental users, governmental administrators, informed activists and econumenistic care-givers. Done carefully and transparently, this pragmatic kind of collaborative ‘science’ provides reliable insight that is relatively impervious to pseudo-scientific attacks from deniers promoting contrary agendas.

Endocrine disrupting chemicals in aquatic environments: A potential reason for organism extinction?

The hazards of endocrine-disrupting chemicals (EDCs) in natural ecosystems are increasingly drawing public attention. These chemical agents affect aquatic life and its proliferation and can eventually cause reduced population density and species biodiversity. At present, EDCs are being considered as possible reasons for the functional degradation of aquatic ecosystems. Field and laboratory studies suggest that EDCs can disrupt the reproductive and developmental health of various species. Molecular evidence shows that EDCs exhibit genotoxicity and can destroy genetic diversity and structure. Evolutionary toxicology further demonstrates that EDCs can affect the pattern of natural selection and eventually lead to evolutionary potential (or adaptability) loss. Historical statistics and ecological risk estimation provided additional robust data to prove that EDCs contribute to population density and biomass decline. Therefore, EDCs may be a latent cause of aquatic species loss or extinction. In the present article, the extinction risk attributable to EDCs are briefly reviewed and discussed based on the aforementioned factors. The present study aims to assess the species vulnerability to extinction under EDCs exposure and provide a scientific basis for making policy decisions on wildlife resource conservation.

Biomonitoring as a prerequisite for sustainable water resources: a review of current status, opportunities and challenges to scaling up in East Africa

Abstract Degradation of aquatic ecosystems in the Lake Victoria basin (LVB) and the rest of East Africa has elicited concern because of its bearing on social and economic development. Rapid population growth, industrialization and its associated urbanization, agricultural intensification and habitat loss have increased pressure on the integrity of water resources. Costs associated with traditional approaches to monitoring water quality have become prohibitive while not giving reliable early warning signals on resource condition to aquatic resource managers. The purpose of this paper is to explore approaches to developing macroinvertebrate- and fish-based biomonitoring tools in the LVB and East Africa and the challenges they face through a review of studies that have been carried out in the region. The hypothesis is that aquatic biota in the LVB provides cost-effective and integrative measures of the physical and chemical habitat conditions thus necessitating their use in assessment and monitoring of water resources. In the LVB macroinvertebrate and fish based indices of biotic integrity (IBIs) have demonstrated their utility in identifying sources of impairment, determining the extent of impacts and stand to give natural resource managers a scientifically defensible rationale for developing guidelines for conservation and management. Despite this significant step, however, adoption and use of indices as part of regular monitoring programs are yet to be realized. We recommend for the advancement and adoption of biological criteria as an integrated approach to monitoring human-induced stress in riverine ecosystems of the East Africa region.

Effect of Decing Salts on Ion Concentrations in Urban Stormwater Runoff

Stormwater draining from impervious surfaces in urban areas often contains readily soluble salts in runoff, which contribute dramatically to the degradation of aquatic ecosystem. The concentrations of potassium (K), cadmium (Ca), sodium (Na), magnesium (Mg), chloride (Cl) and sulfate (SO42-) in stormwater runoff in the urban areas of Shenyang city were measured in 4 rainfall events during July 2009 to June 2010. The results showed that there was an obvious increasing of salt ions concentrations in stormwater runoff samples, especially Na and Cl. It is also found that readily soluble salts ions in stormwater runoff peaked at the first storm event after winter. This study demonstrated that the applied deicing salts in winter significantly contributed to the increasing concentrations of K, Ca, Na, Mg, Cl, and SO42- in urban stormwater runoff. It is evident that the application of deicing salts in cold regions of China every year has had adverse impacts on the aquatic ecology through stormwater runoff.

Water, People, and Sustainability—A Systems Framework for Analyzing and Assessing Water Governance Regimes

Freshwater resources might become the most limited resource in the future due to rising demands, climate change, and the degradation of aquatic ecosystems. While the urgency of this challenge is uncontested, water governance regimes still struggle to employ suitable responses. They lack of: taking a comprehensive perspective on water systems; focusing on social actors, their actions, needs, intentions, and norms as drivers of water systems; engaging in a discourse on tangible goals to provide direction for governance efforts; and promoting a comprehensive perspective on water sustainability that equally recognizes depletion, justice, and livelihood issues in the long-term. We present an approach that intends to overcome these limitations by putting the focus on what people do with water, and why, along with the impacts of these doings. First, we outline an integrated approach to water governance regimes, and then, we present a holistic set of principles by which to evaluate sustainable water governance. Solution-oriented research applying this approach integrates natural sciences and engineering perspectives on water systems with social science studies on water governance, while also specifying and applying normative principles for water sustainability. The approach we develop herein can be used to reform and innovate existing water governance regimes as well as stimulate transformative governance research.

Ecological Risk of Heavy Metals Pollution in Sediments of Beijiang River

As a result of rapid economic development and urbanization, water pollution and degradation of aquatic ecosystems have caused massive damage to the functions and integrity of water resources. The Hakanson potential ecological risk index method for heavy metals toxicity assessment have been used to estimate the ecological risk of Heavy Metals Pollution in Sediments of Beijiang River. The results shows that the average concentration of Cu, Pb, Zn, Ni, Cd, Cr, Hg in sediments is 59.72, 111.29, 218.93, 15.52, 5.70, 5.70 mg/kg, 0.32ug/kg respectively. The content of Hakanson potential ecological risk index of different heavy metals could be shown as Cd> Pb> Cu> Zn> Ni> Cr> Hg. Heavy metals in several samples of the sediments have posed a serious threat on the ecosystem.

Symposium summary: Conservation biogeography

ISSN 1948‐6596 news and update symposium summary Conservation biogeography A contributed session at the 5th International Biogeography Society Conference – Heraklion, Greece, 7–11 January 2011 Theory and analyses developed in biogeography can provide new and valuable insights into how to conserve diversity, especially in an era of in‐ creased human degradation of both terrestrial and aquatic ecosystems, coincident with climate change (Whittaker et al. 2005). Inspired by in‐ creasing research in the field, and by Richard Ladle and Rob Whittaker’s new edited book ‘Conservation Biogeography’ (2011), the Interna‐ tional Biogeography Society devoted a contrib‐ uted session to conservation biogeography at its fifth biennial conference. The session covered six related themes: biotic homogenization, invasive species, agricultural ecology, disease ecology, re‐ serve design and communicating conservation biogeography to the general public. Climate change, also an important theme in conservation biogeography, was discussed in its own contrib‐ uted paper session. In the first talk, Martin Winter and col‐ leagues evaluated the extent to which invasive species lead to homogenization of species, traits and phylogenetic composition of vascular plants and vertebrates in North America and Europe. Their analyses considerably extend current work which has mostly been conducted at the species level and has not evaluated all three levels of di‐ versity simultaneously. They found that all three levels of diversity were influenced by non‐native species, and communities within and among the two regions are becoming increasingly similar. Nonetheless, climatic differences and geographic distance between North America and Europe still seem to limit homogenization. Also on the theme of invasions, Alejandro Ordonez (and co‐author Olff Han) evaluated how patterns of species and functional trait distribution of co‐occurring native plants varied across a nested series of spatial scales. Their analyses revealed the importance of both trait‐based environmental filtering and local‐ scale factors on the distribution of invasive spe‐ cies. George Roderick and colleagues contrib‐ uted a different perspective on the topic of com‐ munity assembly. They used a series of case stud‐ ies of crops and their herbivorous pests and natu‐ ral enemies to uncover patterns of assembly of co ‐occurring species in the Mediterranean. They found that some herbivores and their natural ene‐ mies were already present in the region before crop domestication, while others were associated with subsequent movements of domesticated crops into the region, both early and more recent. The variety of mechanisms by which pests of crop‐ plants moved into the Mediterranean highlights the complexity of the origins of these multispecies interactions, and the challenges associated with conserving—the earliest known—native diversity . Harris Nyeema (with co‐author Robert Dunn) also evaluated multispecies interactions and the diver‐ sity of co‐occurring species, in their study of carni‐ vores and their parasites. They modeled host– parasite associations to explore the consequences of loss of carnivore diversity (29 species) in North America on zoonoses (i.e., diseases transmitted between humans and wildlife) and the implica‐ tions for parasite diversity and conservation. They showed that the loss of carnivores was a potential human and wildlife health risk, and a concern for parasite conservation because it increased the overall proportion of zoonotic parasites (relative to non‐zoonotic parasites) and parasite homoge‐ neity. Lira‐Noriega, Villalobos and colleagues pre‐ sented a method to simultaneously analyze spe‐ cies richness and range size to indentify distinctive assemblages of species. Distinctive assemblages are both species rich and harbour small‐ranged species, the combination of which is not always included in conservation assessments. They found that distinct assemblages are poorly represented within the Mexican national reserve system, and thus these tools have clear conservation value. frontiers of biogeography 3.1, 2011 — © 2011 the authors; journal compilation © 2011 The International Biogeography Society

Developing environment-specific water quality guidelines for suspended particulate matter

It is generally well recognised that suspended particulate matter (SPM), from nano-scale particles to sand-sized sediments, can cause serious degradation of aquatic ecosystems. However, at present there is a poor understanding of the SPM conditions that water quality managers should aim to achieve in contrasting environments in order to support good ecological status. In this article, we analyse long-term SPM data collected from a wide range of reference-condition temperate environments in the UK (638 stream/river sites comprising 42 different ecosystem-types). One-way analysis of variance reveals that there is a statistically significant difference (p < 0.001) between the background SPM concentrations observed in contrasting ecosystems that are in reference condition (minimal anthropogenic disturbance). One of the 42 ecosystems studied had mean background concentrations of SPM in excess of the current European Union (EU) water quality guideline, despite being in reference condition. The implications of this finding are that the EU’s current blanket water quality guideline (25 mg L−1 for all environments) is inappropriate for this specific ecosystem-type which will be non-compliant with the guideline regardless of the intensity of land-use. The other 41 ecosystems studied had mean concentrations below the current EU water quality guideline. However, this does not necessarily mean that the guideline is appropriate for these ecosystems, as previous research has demonstrated that detrimental impacts can be experienced by some freshwater organisms, of all trophic levels, when exposed to concentrations below 25 mg L−1. Therefore, it is suggested here that it is likely that some ecosystems, particularly those with mean concentrations in the 0.00–5.99 mg L−1 range, require much lower guideline values in order to be effectively protected. We propose a model for predicting environment-specific water quality guidelines for SPM. In order to develop this model, the 638 reference condition sites were first classified into one of five mean background SPM ranges (0.00–5.99, 6.00–11.99, 12.00–17.99, 18.00–23.99 and >24.00 mg L−1). Stepwise Multiple Discriminant Analysis (MDA) of these ranges showed that a site’s SPM range can be predicted as a function of: mean annual air temperature, mean annual precipitation, mean altitude of upstream catchment, distance from source, slope to source, channel width and depth, the percentage of catchment area comprised of clay, chalk, and hard rock solid geology, and the percentage of the catchment area comprised of blown sand as the surface (drift) material. The MDA technique, with cross-validation (Wilks-Lambda 0.358, p 0.000), can predict the correct or the next closest SPM range of a site in 90% of cases. This technique can also predict SPM range membership in a probabilistic manner, allowing for an estimate of uncertainty to be made in the allocation of a site to an environment-specific SPM range.

Potential Use of Cyclopoida (Crustacea, Copepoda) as Trophic State Indicators in Tropical Reservoirs

The pelagic zones of fifty three Sao Paulo State reservoirs were sampled as a part of the project “Diversity of zooplankton in relation to conservation and degradation of aquatic ecosystems in the State of Sao Paulo”, within the Biota/Fapesp Program (1999 – 2003). The trophic state index (TSI) was calculated, using total phosphorus and chlorophyll a. The Cyclopoida (Copepoda) populations were analyzed, and richness and relative abundance of the dominant species determined. Most values of the TSI ranged from oligotrophic to mesotrophic. The species richness did not present linear relationships with the TSI values. Nine species of Cyclopoida were dominant. Thermocyclops decipiens was the most frequently dominant species, followed by T. minutus, Mesocyclops ogunnus, T. inversus, T. iguapensis, Microcyclops anceps, Tropocyclops prasinus, Microcyclops alius and Mesocyclops longisetus. Correlations between the abundances of different species were highly negative, with values over 85%, especially between the Thermocyclops species. The species that are potential bioindicators due to the relationship between their dominance and reservoir trophic state are the following: Thermocyclops decipiens and Tropocyclops prasinus as indicators of mesotrophic/eutrophic systems; Thermocyclops inversus and Microcyclops anceps as indicators of oligotrophic/mesotrophic systems, Thermocyclops minutus and T. iguapensis as indicators of oligotrophic systems and Mesocyclops ogunnus as indicator of eutrophic systems.

Assessment of instream structures for habitat improvement for two critically endangered fish species

The number of fish habitat improvement schemes has greatly increased in response to the widespread degradation of aquatic ecosystems. However, many of these enhancement projects often fail to create expected habitat conditions, because they are rarely planned and executed with inputs from the species’ habitat requirements throughout their life histories, and it is frequently assumed that the implementation of a specific instream structure for habitat improvement will always benefit all species present. Using a 2D hydraulic model, the present study evaluates the potential habitat improvement for two critically endangered fish species—the Southwestern arched-mouth nase Iberochondrostoma almacai and the Arade chub Squalius aradensis—resulting from simulating the introduction of different instream structures (islands, lateral bays, and deflectors) in a modified Mediterranean river reach. The introduction of islands in the river channel was found to be the best improvement measure for YOY and juvenile nase and chub, as shown by increases in the mean annual Weighted Usable Area (WUA) of more than 100 and 50%, respectively, compared to the present conditions. On the other hand, the simulation with current deflectors proved to be the worst scenario, particularly for nase, with mean annual WUA decreasing by 3.6, 17.8 and 22.7% for YOY, juveniles and adults, respectively. The findings of this study point to the need to account for different species life-history stages when modelling the implementation of instream structures for habitat improvement and also provide a sound basis for future conservation-related studies conducted in Mediterranean rivers that harbour other threatened “sister” species.

Innovation in Stormwater Management in Canada: The Way Forward

Abstract Rapid urban expansion, increased traffic, ageing infrastructure, greater climatic variability, and the need for enhanced sustainability of urban water resources pose significant challenges to conventional stormwater management. Innovative approaches are needed in order to mitigate the risk of flooding, pollution, and aquatic ecosystem degradation, and enhance beneficial uses of urban waters. To examine such approaches, a series of three regional conferences on innovative stormwater management were held in Vancouver, Calgary, and Toronto during 2007 to 2008 under the sponsorship of the Canadian Water Network (CWN) and the Canadian Mortgage and Housing Corporation (CMHC). Authors of selected conference papers providing information on innovative approaches to mitigating the risk of flooding and reducing pollution impacts at the property, neighbourhood, and watershed scales were then invited to submit journal papers, and those accepted in the review process were included in this Special Issue of the Water Quality Research Journal of Canada. An overview of the selected papers indicates that no single innovative measure is adequate under all circumstances,and a multibarrier approach is deemed to be most effective. Examples of innovations at the property level include harvesting roof runoff and reusing water, managing rainwater by infiltration in swales and into soils in bioretention areas, minimizing impervious surfaces, and using pervious pavement. At the neighbourhood level, runoff impacts are mitigated by designing roads without curbs, gutters, and drain pipes, and diverting runoff into infiltration channels, swales, and wetlands. Creating roads and parking lots with pervious pavement and draining runoff from such surfaces into infiltration basins is also discussed. Among stormwater quality source controls, potential effects of street sweeping on runoff quality enhancement were assessed. New innovations at the watershed scale include: (a) the creation of wide riparian buffer zones that can detain water, remove sediments, and mitigate nutrient export and other pollutant effects, (b) the minimization of channelization of streams and rivers, and (c) the designation of floodwater storage areas. A new water balance model that is linked to a global information system (GIS) and works at all the three scales offers the best option to conceptualize stormwater problems, and their mitigation, in urban watersheds. Finally, the aim of this Special Issue is to promote examples of successful innovative approaches to improving stormwater management in Canadian cities, hoping that other practitioners will build on this experience and bring stormwater management practice to the next higher level.

Aquatic macroinvertebrates of the Jablanica river, Serbia

Research on the community of aquatic macroinvertebrates was carried out during 2005 and 2006 at four sampling sites along the Jablanica River, a right-hand tributary of the Kolubara River. Fifty-seven taxa were recorded in the course of the investigation. The most diverse group was Ephemeroptera, followed by Trichoptera and Plecoptera. Members of the Rhitrogena semicolorata group were the most abundant. Our results could be the basis for evaluation of the influence of damming of the Jablanica River on the status of its water and can serve as a model for studying the influ?ence of hydromorphological degradation of aquatic ecosystems.

Ecology and the Limits of Justice: Establishing Capability Ceilings in Nussbaum's Capabilities Approach

Human impacts on large‐scale ecological interactions effectively confer fundamental advantages of wealth and power to some members of society and not to others. As illustrated here by reference to a 1993 cholera outbreak resulting from degradation of aquatic ecosystems, these impacts can pose barriers to the normal channels through which one might pursue individual advantage, thereby raising tensions for liberal theories of justice that are committed both to basic liberties and to distributive fairness. I first illustrate these tensions by reference to John Rawls's theory. I then argue that although Nussbaum's theory, which emerged in dialogue with Rawls's, improves upon it in this regard, it remains subject to the same basic tensions. Instituting ‘capability ceilings’ that impose a limit on the set of basic opportunities available to people would help resolve this tension. Thus, in addition to Nussbaum's proposal for establishing capability thresholds, I defend capability ceilings as a friendly amendment to her theory.

Impacts of land disturbance on aquatic ecosystem health: Quantifying the cascade of events

The impacts of land disturbance on streams have been studied extensively, but a quantitative mechanism of stream degradation is still lacking. Small changes in land use result in changes in physical and chemical characteristics in the stream, which significantly alter biotic integrity. The objective of this study was to quantify the mechanisms of aquatic ecosystem degradation in streams impacted by watershed urbanization. By quantifying the development level and the changes in the physical parameters of receiving streams, the effects of land use change can be illustrated in a conceptual model and evaluated using a traditional ecological risk assessment framework. Three 1st-order streams draining catchments undergoing varying stages of land development were examined in the upper Piedmont physiographic province of South Carolina, U.S.A. A disturbance index was developed to quantify the changes in land use on a monthly basis. This normalized disturbance index (NDI) was quantitatively linked to an increase in the percentage of impervious cover, stormwater runoff, storm-event total suspended solid (TSS) concentrations, and the North Carolina biotic index (NCBI). The NDI was inversely related to a decline in habitat, median bed-sediment particle size, and benthic index of biotic integrity (BIBI). Unlike the percentage of impervious cover, the NDI facilitated the development of strategies for multiple scales of regulation. Predictive multivariate regressions were developed for storm-event TSS concentrations, the BIBI, and the NCBI. These regressions can be used to develop improved regulations for the effects of development and can lead to better implementation of best management practices, improved monitoring of land use change, and more sustainable development.

Reuse of Urban Runoff in Australia: A Review of Recent Advances and Remaining Challenges

The degradation of aquatic ecosystems due to hydrologic and water quality impacts of urbanization, combined with increasing water scarcity, has generated increasing interest in the harvesting of urban storm water. This paper reviews the rationale for integrated storm water treatment and harvesting and synthesizes recent advances and trends and knowledge gaps that limit its application. Storm water harvesting is shown to be a viable alternative water supply and to provide a potential solution to the increases in runoff frequency and peak flows that occur as a result of catchment urbanization. In general, treatment technologies for storm water harvesting have been adapted from existing "water-sensitive urban design" approaches, with limited use of traditional water supply and wastewater technologies. Risk management is often lacking, in part due to a lack of relevant guidance. Reported performance shows variable levels of potable water savings, with cases of up to 100% substitution recorded. Costs of storm water harvesting systems are shown to be inversely related to their scale. The limited cost data show the importance of context, with the harvested water costing more or less than alternative supplies, depending on the cost of the alternative. Limited data exist on environmental benefits, such as reductions in pollutant loads and flow peaks. Implementation of storm water harvesting systems is impeded by inadequate data on risk, lifecycle costs, externalities, and water-energy tradeoffs. Furthermore, retrofit of storm water harvesting into existing urban areas is proving to be a challenge, creating an urgent need for specific technologies for use in retrofit situations.

Mapping Chlorophyll- a Concentrations in West Lake, China using Landsat 7 ETM+

Eutrophication is a persistent problem that affects the ecological health of many shallow lakes in China. An indicator used to monitor trophic status is chlorophyll-a; however, collection and analysis can be spatially limiting and time consuming. In this study we utilized Landsat 7 ETM+ (Path/Row 119/39) imagery for West Lake, Hangzhou, to map chlorophyll-a concentrations. An optimal linear regression model with the band ratio ETM+3/ETM+1 (independent) and concurrent field-collected water quality measurements (dependant) was developed. The resulting model, lnChl.= 5.009 (ETM+3/ETM+1)-1.855, showed a strong (R 2 = 0.815) ability to accurately map the distribution of chlorophyll-a. The straightforward approach carried out to assess this fresh-water lake in a rapidly developing region increased the level of information required to combat aquatic ecosystem degradation.

Utilization of common ditch vegetation in the reduction of fipronil and its sulfone metabolite

Fipronil, a phenylpyrazole insecticide, and its oxidative sulfone metabolite are two potential pollutants from treated rice and cotton production. A consequence of these pollutants occurring in surface runoff is degradation of downstream aquatic ecosystems. Utilization of primary intercept drainage ditches as management practices to reduce fipronil concentrations and loads has not been examined. This study used ditch mesocosms planted with monospecific stands of common emergent wetland vegetation to determine if certain plant species were more proficient in fipronil mitigation. Three replicates of four plant species were compared against a non-vegetated control to determine differences in water column outflow concentrations (microg L(-1)) and loads (microg). There were no significant differences between vegetated and control treatments in outflow concentrations (F = 0.35, P = 0.836) and loads (F = 0.35, P = 0.836). The range of fipronil reduction was 28-45% for both concentration and load. Unlike fipronil, fipronil sulfone concentrations and load increased by 96-328%. The increase in fipronil sulfone was hypothesized as a direct consequence of oxidation of fipronil within each mesocosm. The type of ditch vegetation had no effect on fipronil reduction. Future research needs to examine initial concentrations and hydraulic retention times to examine potential changes in reduction capacities.

Microhabitat use by endangered Iberian cyprinids nase Iberochondrostoma almacai and chub Squalius aradensis

Over the last decade there has been a major rise in the number of attempts at fish conservation and management as a response to the widespread degradation of aquatic ecosystems. The assessments involved are rarely planned and executed with inputs from the species’ life history, particularly their microhabitat use over space and time. The seasonal and size related microhabitat use of two critically endangered cyprinids – the Iberian nase Iberochondrostoma almacai and Iberian chub Squalius aradensis – was examined at seven sites across four small catchments in southwest Portugal. Both species displayed nonrandom microhabitat use. In autumn, nase preferred more sheltered (>50% cover) habitats with small substrata (organic cover and silt) than in summer, while chub were found to occupy significantly fasterflowing habitats areas (>10 cm/s) with coarser substrata (>50 mm particle size) in the spring than in the rest of the year. Size-related analyses indicated that young-of-year (yoy) nase used coarser substrata (>5 mm particle size) and more exposed habitats (<50% cover) than adult nase. Adult chub, on the other hand, occupied coarser substrata (>50 mm particle size) and faster-flowing areas (>10 cm/s) than yoy and juveniles. Based on these findings, it was possible to assign the species to ecological guilds and to classify them as limnophilic (nase) and eurytopic and lithophilic (chub). Both species generally occupied distinct microhabitats, although resource-use overlap was significant in summer. During this season, overlap was found between yoy nase and chub, juvenile nase and juvenile/adult chub, and between adults of both species. The present study identified key factors in the species’ habitat requirements and helped develop management recommendations for river restoration that may have a wider application, particularly for other Mediterranean-type rivers.