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Dive into the research topics where Lorraine Maltby is active.

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Featured researches published by Lorraine Maltby.


Environmental Toxicology and Chemistry | 2005

Insecticide species sensitivity distributions: Importance of test species selection and relevance to aquatic ecosystems

Lorraine Maltby; Naomi Blake; T.C.M. Brock; Paul J. Van den Brink

Single-species acute toxicity data and (micro)mesocosm data were collated for 16 insecticides. These data were used to investigate the importance of test-species selection in constructing species sensitivity distributions (SSDs) and the ability of estimated hazardous concentrations (HCs) to protect freshwater aquatic ecosystems. A log-normal model was fitted to a minimum of six data points, and the resulting distribution was used to estimate lower (95% confidence), median (50% confidence), and upper (5% confidence) 5% HC (HC5) values. Species sensitivity distributions for specific taxonomic groups (vertebrates, arthropods, nonarthropod invertebrates), habitats (saltwater, freshwater, lentic, lotic), and geographical regions (Palaearctic, Nearctic, temperate, tropical) were compared. The taxonomic composition of the species assemblage used to construct the SSD does have a significant influence on the assessment of hazard, but the habitat and geographical distribution of the species do not. Moreover, SSDs constructed using species recommended in test guidelines did not differ significantly from those constructed using nonrecommended species. Hazardous concentrations estimated using laboratory-derived acute toxicity data for freshwater arthropods (i.e., the most sensitive taxonomic group) were compared to the response of freshwater ecosystems exposed to insecticides. The sensitivity distributions of freshwater arthropods were similar for both field and laboratory exposure, and the lower HC5 (95% protection with 95% confidence) estimate was protective of adverse ecological effects in freshwater ecosystems. The corresponding median HC5 (95% protection level with 50% confidence) was generally protective of single applications of insecticide but not of continuous or multiple applications. In the latter cases, a safety factor of at least five should be applied to the median HC5.


BioScience | 2012

Biodiversity and the Feel-Good Factor: Understanding Associations between Self-Reported Human Well-Being and Species Richness

Martin Dallimer; Katherine N. Irvine; Andrew M. J. Skinner; Zoe G. Davies; James R. Rouquette; Lorraine Maltby; Philip H. Warren; Paul R. Armsworth; Kevin J. Gaston

Over half of the worlds human population lives in cities, and for many, urban greenspaces are the only places where they encounter biodiversity. This is of particular concern because there is growing evidence that human well-being is enhanced by exposure to nature. However, the specific qualities of greenspaces that offer the greatest benefits remain poorly understood. One possibility is that humans respond positively to increased levels of biodiversity. Here, we demonstrate the lack of a consistent relationship between actual plant, butterfly, and bird species richness and the psychological well-being of urban greenspace visitors. Instead, well-being shows a positive relationship with the richness that the greenspace users perceived to be present. One plausible explanation for this discrepancy, which we investigate, is that people generally have poor biodiversity-identification skills. The apparent importance of perceived species richness and the mismatch between reality and perception pose a serious challenge for aligning conservation and human well-being agendas.


Ecological Applications | 1999

STUDYING STRESS: THE IMPORTANCE OF ORGANISM-LEVEL RESPONSES

Lorraine Maltby

The importance of studying the effects of stress on individual organisms is addressed by considering the use of individual-level information to: (1) elucidate the mechanistic bases of interpopulation variation; (2) predict population-level effects; and (3) monitor stress in natural communities. Examples discussed include interpopulation variation in the sensitivity of freshwater shrimps to zinc stress; the use of individual-based models to predict the effects of copper stress on earthworm populations; the use of single-species in situ assays to monitor pollution. It is contended that knowledge of organism-level responses is essential for understanding how stressors cause adverse biological effects and the strategies adopted by organisms to tolerate stress. It is also contended that the effects of stressors on populations can be predicted from a knowledge of the effects of stressors on individual energy budgets. Organism-level responses can be used to monitor stress in natural environments. In situ assays,...


Hydrobiologia | 1989

Scope for growth in Gammarus pulex, a freshwater benthic detritivore

Caroline Naylor; Lorraine Maltby; P. Calow

Although toxic substances affect the physiological processes of individual organisms, their ecological impacts occur at the population and community levels. However, physiological processes can often be assessed more easily and precisely than population and community ones. Here we argue that ‘scope for growth’, the difference between the energy input to an organism from its food and the output from respiratory metabolism, can give a good physiological measure of stress that, at least in principle, is straightforwardly related to population and community processes. We describe, in detail, how ‘scope for growth’ can be measured in Gammarus pulex (Crustacea, Amphipoda). The results indicate that both zinc and low pH can significantly reduce the scope for growth of individuals and that the most sensitive component of the energy budget is food absorption.


Oecologia | 1993

Importance of fungi in the diet of Gammarus pulex and Asellus aquaticus. II: Effects on growth, reproduction and physiology

Manuel A. S. Graça; Lorraine Maltby; P. Calow

An important component of the interaction between macroinvertebrates and leaf litter in streams in the extent to which consumers can differentiate between undecomposed and decomposing leaves. The detritivores Gammarus pulex and Asellus aquaticus fed preferentially on conditioned rather on unconditioned leaf material. Growth in A. aquaticus was significantly reduced when unconditioned leaves were provided, but in G. pulex no significant effect of conditioning on growth was observed. The capacity of G. pulex to tolerate reductions in food quality seems to be a consequence of a compensatory system in which respiration rates change to compensate for reductions in food quality. In this way a constant growth rate is maintained. Increases in ingestion rates to compensate for low quality food were not observed.


Oecologia | 1993

Importance of fungi in the diet of Gammarus pulex and Asellus aquaticus I: feeding strategies

Manuel A. S. Graça; Lorraine Maltby; P. Calow

The importance of fungi in the trophic biology of the freshwater detritivores Gammarus pulex and Asellus aquaticus was investigated. Inspection of leaves used in feeding trials indicated that whereas A. aquaticus scrapes at the leaf surface, G. pulex bites through the leaf material. Both species discriminated between fungal mycelia, fungally colonized and uncolonized leaf material but, although A. aquaticus selectively consumed fungal mycelia, G. pulex fed preferentially on leaf material. Fungi appear to be an important food source for A. aquaticus and selection of food material was positively correlated with fungal biomass. In contrast, for G. pulex, fungi appear to be more important as modifiers of leaf material. However, no significant correlations were found between food preference and any of the leaf modifications measured.


Human and Ecological Risk Assessment | 2006

Predictive Value of Species Sensitivity Distributions for Effects of Herbicides in Freshwater Ecosystems

P.J. van den Brink; N. Blake; T.C.M. Brock; Lorraine Maltby

ABSTRACT In this article we present a review of the laboratory and field toxicity of herbicides to aquatic ecosystems. Single-species acute toxicity data and (micro)mesocosm data were collated for nine herbicides. These data were used to investigate the importance of test species selection in constructing species sensitivity distributions (SSDs), and in estimating hazardous concentrations (i.e., HC5) protective for freshwater aquatic ecosystems. A lognormal model was fitted to toxicity data (acute EC50s and chronic NOECs) and the resulting distribution used to estimate lower (95% confidence), median (50% confidence), and upper (5% confidence), HC5 values. The taxonomic composition of the species assemblage used to construct the SSD does have a significant influence on the assessment of hazard and only sensitive primary producers should be included for the risk assessment of herbicides. No systematic difference in sensitivity between standard and non-standard test species was observed. Hazardous concentrations estimated using laboratory-derived acute and chronic toxicity data for sensitive freshwater primary producers were compared to the response of herbicide-stressed freshwater ecosystems using a similar exposure regime. The lower limit of the acute HC5 and the median value of the chronic HC5 were protective of adverse effects in aquatic micro/mesocosms even under a long-term exposure regime. The median HC5 estimate based on acute data was protective of adverse ecological effects in freshwater ecosystems when a pulsed or short-term exposure regime was used in the microcosm and mesocosm experiments. There was also concordance between the predictions from the effect model PERPEST and the concentrations at which clear effects started to emerge in laboratory and field studies. However, compared to the SSD concept, the PERPEST model is able to provide more information on ecological risks when a common toxicological mode of action is evaluated as it considers both recovery and indirect effects.


Science of The Total Environment | 2012

Development of a framework based on an ecosystem services approach for deriving specific protection goals for environmental risk assessment of pesticides

Karin Nienstedt; T.C.M. Brock; Joke van Wensem; Mark Montforts; Andy Hart; Alf Aagaard; Anne Alix; Joes Boesten; Stephanie K. Bopp; Colin D. Brown; Ettore Capri; Valery E. Forbes; Herbert Köpp; Matthias Liess; Robert Luttik; Lorraine Maltby; José Paulo Sousa; Franz Streissl; Anthony Hardy

General protection goals for the environmental risk assessment (ERA) of plant protection products are stated in European legislation but specific protection goals (SPGs) are often not precisely defined. These are however crucial for designing appropriate risk assessment schemes. The process followed by the Panel on Plant Protection Products and their Residues (PPR) of the European Food Safety Authority (EFSA) as well as examples of resulting SPGs obtained so far for environmental risk assessment (ERA) of pesticides is presented. The ecosystem services approach was used as an overarching concept for the development of SPGs, which will likely facilitate communication with stakeholders in general and risk managers in particular. It is proposed to develop SPG options for 7 key drivers for ecosystem services (microbes, algae, non target plants (aquatic and terrestrial), aquatic invertebrates, terrestrial non target arthropods including honeybees, terrestrial non-arthropod invertebrates, and vertebrates), covering the ecosystem services that could potentially be affected by the use of pesticides. These SPGs need to be defined in 6 dimensions: biological entity, attribute, magnitude, temporal and geographical scale of the effect, and the degree of certainty that the specified level of effect will not be exceeded. In general, to ensure ecosystem services, taxa representative for the key drivers identified need to be protected at the population level. However, for some vertebrates and species that have a protection status in legislation, protection may be at the individual level. To protect the provisioning and supporting services provided by microbes it may be sufficient to protect them at the functional group level. To protect biodiversity impacts need to be assessed at least at the scale of the watershed/landscape.


Ecotoxicology and Environmental Safety | 1990

Effect of Stress on a Freshwater Benthic Detritivore: Scope for Growth in Gammarus pulex

Lorraine Maltby; Caroline Naylor; P. Calow

Scope for growth (SfG), a measure of energy balance (between food intake and metabolic output) within animals, has been used as an indicator of pollution stress in marine systems. However, it has not been used commonly in freshwater systems and here we investigate the sensitivity of SfG in Gammarus pulex, a benthic freshwater crustacean, under conditions often associated with pollution. The effects of four specific substances were investigated; a metal (zinc), an organic (3,4-dichloroaniline), and two dissolved gases (oxygen and ammonia). In all cases SfG was reduced by the stress, primarily due to a depression in energy intake. Only with ammonia was energy output (respiration) significantly affected.


Water Research | 1995

Sensitivity of the crustaceans Gammarus pulex (L.) and Asellus aquaticus (L.) to short-term exposure to hypoxia and unionized ammonia: Observations and possible mechanisms

Lorraine Maltby

Abstract Episodic organic pollution results in short-term increases in the ammonia concentration and reductions in the dissolved oxygen (DO) concentration of receiving waters. This study provides information on the lethal effects of 24-h pulses of high ammonia and low DO on two common freshwater crustaceans. Both inter and intraspecific differences in sensitivity were observed. Asellus aquaticus was five times more resistant to hypoxia and two times more resistant to unionized ammonia and Gammarus pulex . Moreover, for both stressors, juveniles were less susceptible than adults. Interspecific differences in ventilation rate and blood characteristics (i.e. haemocyanin concentration and oxygen affinity) could explain interspecific differences in susceptibility to hypoxia, and possibly ammonia. Intraspecific differences in ventilation rate may partly explain the reduced susceptibility of juvenile G. pulex to these stressors.

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P. Calow

University of Minnesota

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T.C.M. Brock

Wageningen University and Research Centre

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G.H.P. Arts

Wageningen University and Research Centre

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Paul J. Van den Brink

Wageningen University and Research Centre

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Yi-ping Chen

Chinese Academy of Sciences

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