- Amsterdam
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The ecosystem services (EcoS) concept is being used increasingly to attach values to natural systems and the multiple benefits they provide to human societies. Ecosystem processes or functions only become EcoS if they are shown to have... more
The ecosystem services (EcoS) concept is being used increasingly to attach values to natural systems and the multiple benefits they provide to human societies. Ecosystem processes or functions only become EcoS if they are shown to have social and/or economic value. This should assure an explicit connection between the natural and social sciences, but EcoS approaches have been criticized for retaining little natural science. Preserving the natural, ecological science context within EcoS research is challenging because the multiple disciplines involved have very different traditions and vocabularies (common-language challenge) and span many organizational levels and temporal and spatial scales (scale challenge) that define the relevant interacting entities (interaction challenge). We propose a network-based approach to transcend these discipline challenges and place the natural science context at the heart of EcoS research.
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The study of ecological services (ESs) is fast becoming a cornerstone of mainstream ecology, largely because they provide a useful means of linking functioning to societal benefits in complex systems by connecting different organizational... more
The study of ecological services (ESs) is fast becoming a cornerstone of mainstream ecology, largely because they provide a useful means of linking functioning to societal benefits in complex systems by connecting different organizational levels. In order to identify the main challenges facing current and future ES research, we analyzed the effects of the publication of the Millennium Ecosystem Assessment (MEA, 2005) on different disciplines. Within a set of topics framed around concepts embedded within the
MEA, each co-author identified five key research challenges and, where feasible, suggested possible solutions. Concepts included those related to specific service types (i.e. provisioning, supporting, regulating, cultural, aesthetic services) as well as more synthetic issues spanning the natural and social sciences, which often linked a wide range of disciplines, as was the case for the application of network theory. By merging similar responses, and removing some of the narrower suggestions from our sample pool, we distilled the key challenges into a smaller subset. We review some of the historical context to the MEA and identify some of the broader scientific and philosophical issues that still permeate discourse in this field. Finally, we consider where the greatest advances are most likely to be made in the next decade and beyond.
MEA, each co-author identified five key research challenges and, where feasible, suggested possible solutions. Concepts included those related to specific service types (i.e. provisioning, supporting, regulating, cultural, aesthetic services) as well as more synthetic issues spanning the natural and social sciences, which often linked a wide range of disciplines, as was the case for the application of network theory. By merging similar responses, and removing some of the narrower suggestions from our sample pool, we distilled the key challenges into a smaller subset. We review some of the historical context to the MEA and identify some of the broader scientific and philosophical issues that still permeate discourse in this field. Finally, we consider where the greatest advances are most likely to be made in the next decade and beyond.
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Availability of macrophyte habitat is recognized as an important driver of aquatic insect communities in peatland drainage ditches; however, eutrophication can lead to the decline of submerged vegetation. While emergent vegetation is able... more
Availability of macrophyte habitat is recognized as an important driver of aquatic insect communities in peatland drainage ditches; however, eutrophication can lead to the decline of submerged vegetation. While emergent vegetation is able to persist in eutrophicated ditches, vegetation removal, carried out during ditch maintenance, can reduce the availability of this habitat. In this study, we applied the landscape filtering approach to determine whether the absence of emergent vegetation is a habitat filter which structures aquatic insect communities in peatland drainage ditches under different trophic conditions. To this end, a field study was carried out in one mesotrophic (Naardermeer) and one eutrophic (Wormer and Jisperveld) peatland in the province of North Holland, The Netherlands. We assigned life history strategies to insect species and applied linear mixed models and redundancy analyses to taxonomic and functional aquatic insect community data. Our results indicate that w...
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The distance–decay relationship has been claimed to be a predictor for biological diversity because it unites several ecological phenomena such as dispersal ability and environmental structure. The effect of long-term disturbances on... more
The distance–decay relationship has been claimed to be a predictor for biological diversity because it unites several ecological phenomena such as dispersal ability and environmental structure. The effect of long-term disturbances on distance decay, however, has been widely overlooked, especially for microorganisms.We examine the effect of eutrophication on the distance–decay relationship in communities of attached diatoms in three peatland areas: mesotrophic, eutrophic and hypertrophic. The study follows a spatially explicit sampling scheme, collecting evenly spaced samples along 6-km sampling tracks.The three areas shared 24% of the total number of species, but the different nutrient levels in the three areas are reflected by the prominence of low profile and planktonic diatom species.Our study demonstrates that eutrophication can affect distance–decay relationships by decreasing turnover rates in microorganisms. Diatom communities are shown to be constrained by both environmental...
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This report on The Potential of Mode of Action (MoA) Information Derived from Non-testing and Screening Methodologies to Support Informed Hazard Assessment, resulted from a workshop organised within OSIRIS (Optimised Strategies for Risk... more
This report on The Potential of Mode of Action (MoA) Information Derived from Non-testing and Screening Methodologies to Support Informed Hazard Assessment, resulted from a workshop organised within OSIRIS (Optimised Strategies for Risk Assessment of Industrial Chemicals through Integration of Non-test and Test Information), a project partly funded by the EU Commission within the Sixth Framework Programme. The workshop was held in Liverpool, UK, on 30 October 2008, with 35 attendees. The goal of the OSIRIS project is to develop integrated testing strategies (ITS) fit for use in the REACH system, that would enable a significant increase in the use of non-testing information for regulatory decision making, and thus minimise the need for animal testing. One way to improve the evaluation of chemicals may be through categorisation by way of mechanisms or modes of toxic action. Defining such groups can enhance read-across possibilities and priority settings for certain toxic modes or chem...
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ABSTRACT The extensive network of waters in the lower part of the Dutch delta is loaded with nutrients and accordingly a uniform ecological classification 'moderate' has been derived. The present study sets out to typify... more
ABSTRACT The extensive network of waters in the lower part of the Dutch delta is loaded with nutrients and accordingly a uniform ecological classification 'moderate' has been derived. The present study sets out to typify the diatom communities in this apparently homogenous environment via self-organizing maps of diatom species composition. Clusters of diatom communities were characterized through the representation of ecological guilds (high and low profile, motile and planktonic) and via a RDA analysis based on either species, genus or ecological guilds together with environmental drivers. Five clusters of diatom communities were identified despite the prominence of omnipresent species. The clusters had different profiles of ecological guilds and were associated with water transparency and sediment type (peat/clay) in addition to the well-established environmental drivers related to eutrophication, but with distinct roles for nitrogen and phosphate concentration. The clusters were interpreted as functional types of community, e.g. communities with a substantial share of planktonic diatom species were found in peat ditches with turbid water. The high consistency found between diatom community classification using species, genus or guilds may allow for a simplified water quality assessment while retaining valuable ecological information. The typology, based on species, genus and ecological guilds underpins the robust use of diatoms as water quality indicators in nutrient rich lentic waters and supports steps to improve ecological conditions.
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ABSTRACT Mineral particles in rivers have been shown to cover adnate algal species, promoting motile and filamentous species. Such effects and the role of detrital particles have not been studied in stagnant waters. In degraded peat... more
ABSTRACT Mineral particles in rivers have been shown to cover adnate algal species, promoting motile and filamentous species. Such effects and the role of detrital particles have not been studied in stagnant waters. In degraded peat lands, detrital particles are very prominent and therefore we studied the interaction of organic particles and attached algae. Field grown communities were translocated to microcosms and exposed to organic particles in the laboratory. Colonization of substrate was also studied in field enclosures that allowed settlement of particles. We compared algal settlement under low particle regime (enclosures) with settlement at high particle concentrations (outside). Suspended particles were found to be trapped by attached algae in proportion to the concentration of particles. The presence of particles in the incubations and field enclosures modified species composition, reducing the share of low-profile forms. These experimental results were verified in a field survey with a wide range of turbidity. The share of low-profile species was lowest in turbid ditches while motile and planktonic algae dominated, in agreement with the results from experiments. It is argued that the strong interactions of attached algae and suspended organic matter found in peat land ditches is a characteristic feature of detritus rich waters.
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... Micronesia 35–36, 598–652. Smith, JL B. (1958). The fishes of the family Eleotridae in the western Indian Ocean. Ichthyological Bulletin of the Department of Ichthyology, Rhodes University 11, 137–163. Whitley, GP (1935). Studies in... more
... Micronesia 35–36, 598–652. Smith, JL B. (1958). The fishes of the family Eleotridae in the western Indian Ocean. Ichthyological Bulletin of the Department of Ichthyology, Rhodes University 11, 137–163. Whitley, GP (1935). Studies in Ichthyology. No. ...
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The REACH legislation describes the “Exposure Based Waiving” (EBW) methodology, that allows reduction of animal tests and that facilitates the Chemical Safety Assessments. We introduced a tiered EBW decision strategy for the aquatic... more
The REACH legislation describes the “Exposure Based Waiving” (EBW) methodology, that allows reduction of animal tests and that facilitates the Chemical Safety Assessments. We introduced a tiered EBW decision strategy for the aquatic environment. Tier 0 in this strategy justifies waiving if it can be demonstrated that exposure of organisms to a chemical will be practically zero (i.e., if no
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Research Interests: Kinetics, Nanomaterials, Nanoparticles, Risk assessment, Multidisciplinary, and 14 moreExposure Assessment, Sediment transport, Ecological Risk Assessment, Dissolution, First-Order Logic, Sedimentation, Aquatic organisms, Sediment Transport, Risk Assessment, Water Movements, Experimental Data, Environment, Geologic Sediments, and Environmental Exposure
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The majority of research on biodiversity–ecosystem functioning in laboratories has concentrated on a few traits, but there is increasing evidence from the field that functional diversity controls ecosystem functioning more often than does... more
The majority of research on biodiversity–ecosystem functioning in laboratories has concentrated on a few traits, but there is increasing evidence from the field that functional diversity controls ecosystem functioning more often than does species number. Given the importance of traits as predictors of niche complementarity and community structures, we (1) examine how the diversity sensu lato of forest trees, freshwater fishes and soil invertebrates might support ecosystem functioning and (2) discuss the relevance of productive biota for ...
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Nematodes are presumably the most numerous Metazoans in terrestrial habitats. They are represented at all trophic levels and are known to respond to nutrient limitation, prey availability, and microbial resources. Predatory nematodes... more
Nematodes are presumably the most numerous Metazoans in terrestrial habitats. They are represented at all trophic levels and are known to respond to nutrient limitation, prey availability, and microbial resources. Predatory nematodes reside at the highest trophic level, and as such their feeding habits could have a major impact on soil food web functioning. Here, we investigate the effects of gender and developmental stage on the nematode body sizes in coarse and loamy soils. Besides Neodiplogasteridae, our predators are much larger than other soil-dwelling nematodes from their early developmental stage onwards. From juvenile to adult, the predatory Aporcelaimellus (Kruskal-Wallis P < 0.001), Dorylaimoides, and Tripyla (both P < 0.01) show great length increases during their developmental growth, in contrast to their possible prey (almost all P < 0.001). Less than 4% of the prey exceeds the length of the predatory adults, but more than 30% of the prey exceeds the length of ...