Water - Water and biodiversity

Title

Eutrophication causes speciation reversal in whitefish adaptive radiations

Reference

Nature 482, 357–362
doi:10.1038/nature10824

Author(s)

P. Vonlanthen, D. Bittner, A. G. Hudson, K. A. Young, R. Müller, B. Lundsgaard-Hansen, D. Roy, S. Di Piazza, C. R. Largiader & O. Seehausen

Study type

Peer Review Journal    

Abstract

Species diversity can be lost through two different but potentially interacting extinction processes: demographic decline and speciation reversal through introgressive hybridization. To investigate the relative contribution of these processes, we analysed historical and contemporary data of replicate whitefish radiations from 17 pre-alpine European lakes and reconstructed changes in genetic species differentiation through time using historical samples. Here we provide evidence that species diversity evolved in response to ecological opportunity, and that eutrophication, by diminishing this opportunity, has driven extinctions through speciation reversal and demographic decline. Across the radiations, the magnitude of eutrophication explains the pattern of species loss and levels of genetic and functional distinctiveness among remaining species. We argue that extinction by speciation reversal may be more widespread than currently appreciated. Preventing such extinctions will require that conservation efforts not only target existing species but identify and protect the ecological and evolutionary processes that generate and maintain species.

Policy theme(s)

Biodiversity >> Threats to biodiversity >> Human impacts
Water >> Water quality >> Water pollution and safety
Water >> Water and biodiversity

Keywords

Entry Source:

Shortlisted for Science for Environment Policy News Alert 

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http://www.nature.com/nature/journal/v482/n7385/full/nature10824.html
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Contact the study author at:

ole.seehausen@eawag.ch

Title

The European reference condition concept: A scientific and technical approach to identify minimally-impacted river ecosystems

Reference

Science of The Total Environment
Volume 420, 15 March 2012, Pages 33–42

Author(s)

Isabel Pardo, Carola Gómez-Rodríguez, Jean-Gabriel Wasson, Roger Owen, Wouter van de Bund, Martyn Kelly, Cathy Bennett, Sebastian Birk, Andrea Buffagni, Stefania Erba, Nicolas Mengin, John Murray-Bligh, Gisela Ofenböeck

Study type

Peer Review Journal    

Abstract

One objective of the European Union (EU)'s Water Framework Directive (WFD: Directive 2000/60/EC) is for all European surface waters to achieve ‘good status’ by 2015. In support of this objective, the EU has facilitated an intercalibration exercise to ensure harmonized definitions of the status of water bodies, reflecting the deviation of their properties (mainly biotic assemblages) from a minimally disturbed state, termed the “reference condition”. One of the major challenges of the WFD has been to find common approaches for defining reference conditions and to define the level of anthropogenic intervention allowed in reference sites. In this paper we describe how river reference sites were selected in the Central-Baltic region of Europe. A list of pressure criteria was provided and 14 Member States (MSs) categorized each criterion according to the method (i.e. measured, field inspection, etc.) used for reference site screening. Additionally, reference land-use and water-chemistry thresholds were agreed among countries in order to base reference site selection on objective criteria. For land-use criteria, a reference threshold and a rejection threshold were established. Sites with all criteria below the reference threshold were considered to be reference sites; sites having most criteria below the reference threshold and only some parameters between the reference and rejection threshold were “possible reference sites”. These sites were retained only after carefully checking the cumulative effects of the pressures using local expertise, and a posteriori water-chemistry evaluation was necessary. In general, the most widespread method for defining a reference site was the measurement of pressures, followed by field inspections and expert judgment. However, some major pressures (e.g. hydromorphological alteration) were evaluated in a number of different ways (e.g. measured, field inspection, expert judgment). Our meta-analyses reveal a need to reinforce standardization in the application of pressure criteria by Member States. The pressure criteria identified in this exercise should be refined and tested with biological data to help in the further validation of minimally disturbed sites (i.e. the WFD “reference condition”) and to provide a firm foundation for ecological status assessment. This in turn would ensure that there is pan-European comparability when evaluating the achievement of environmental objectives.

Policy theme(s)

Water >> River basin management (WFD)
Water >> Water and biodiversity

Keywords

Reference condition; Europe; Rivers; Pressure criteria; Thresholds; Invertebrates

Entry Source:

Selected for Science for Environment Policy News Alert

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http://www.sciencedirect.com/science/article/pii/S0048969712000691
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Contact the study author at:

ipardo@uvigo.es

Title

Reference

Environmental Monitoring and Assessment
Volume 173, Numbers 1-4, 653-667
DOI: 10.1007/s10661-010-1413-8

Author(s)

Ali Hosseini, Justin Emrys Brown, Mark Dowdall, William Standring and Per Strand

Study type

Peer Review Journal

Abstract

Significant shifts in opinion regarding environmental protection from ionising radiation have resulted in the development and availability of bespoke approaches for the assessment of impacts on wildlife from radioactive contaminants. The application of such assessment methodologies to actual situations, however, remains relatively limited. This paper describes the implementation of the ERICA Integrated Approach and associated tools within the context of routine discharges of radioactive materials to a freshwater environment. The article follows the implementation through its relevant stages and discusses strengths and weaknesses of the approach in relation to the case study. For current discharge levels, 137Cs and 60Co constitute the main dose contributors to the majority of reference organisms studied, although 241Am and 3H are the main contributors for the phyto- and zooplankton categories. Patterns are observed depending on whether the reference organism is sediment-associated or not. At current discharge levels, none of the reference organisms exceeded or approached the selected screening level, and impacts on biota could be regarded as negligible.

Policy theme(s)

Risk assessment >> Risk assessment methodologies
Water >> Water quality >> Water pollution and safety
Water >> Water and biodiversity

Keywords

Environmental impact assessment, Radioactivity, Wildlife, Freshwater

Entry Source:

Selected for Science for Environment Policy News Alert

Referred to in EC doc:

N/A

View this study at:

http://www.springerlink.com/content/m877n73u13414nw2/
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Contact the study author at:

justin.brown@nrpa.no

Title

Nano-TiO2 enhances the toxicity of copper in natural water to Daphnia magna

Reference

Environmental Pollution
Volume 159, Issue 3, March 2011, Pages 729-734

Author(s)

Wenhong Fan, Minming Cui, Hong Liu, Chuan Wang, Zhiwei Shi, Cheng Tan and Xiuping Yang

Study type

Peer Review Journal

Abstract

The acute toxicity of engineered nanoparticles (NPs) in aquatic environments at high concentrations has been well-established. This study demonstrates that, at a concentration generally considered to be safe in the environment, nano-TiO2 remarkably enhanced the toxicity of copper to Daphnia magna by increasing the copper bioaccumulation. Specifically, at 2 mg L_1 nano-TiO2, the (LC50) of Cu2þ concentration observed to kill half the population, decreased from 111 mg L_1 to 42 mg L_1. Correspondingly, the level of metallothionein decreased from 135 mg g_1 wet weight to 99 mg g_1 wet weight at a Cu2þ level of 100 mg L_1. The copper was found to be adsorbed onto the nano-TiO2, and ingested and accumulated in the animals, thereby causing toxic injury. The nano-TiO2 may compete for free copper ions with sulfhydryl groups, causing the inhibition of the detoxification by metallothioneins.

Policy theme(s)

Biodiversity >> Threats to biodiversity >> Human impacts
Chemicals >> Pollutants/hazardous substances >> Nanomaterials
Water >> Water and biodiversity

Keywords

Nano-TiO2, Toxicity, Copper, Daphnia magna, Metallothionein

Entry Source:

Shortlisted for Science for Environment Policy News Alert

Referred to in EC doc:

N/A

View this study at:

http://www.sciencedirect.com/science/article/pii/S0269749110005415
There is a fee to view this study in full

Contact the study author at:

fanwh@buaa.edu.cn