Publications by authors named "Christian Mulder"

39 Publications

Global data on earthworm abundance, biomass, diversity and corresponding environmental properties.

Sci Data 2021 05 21;8(1):136. Epub 2021 May 21.

Forest Sciences and Forest Ecology, University of Göttingen, Büsgenweg 1, Göttingen, Germany.

Earthworms are an important soil taxon as ecosystem engineers, providing a variety of crucial ecosystem functions and services. Little is known about their diversity and distribution at large spatial scales, despite the availability of considerable amounts of local-scale data. Earthworm diversity data, obtained from the primary literature or provided directly by authors, were collated with information on site locations, including coordinates, habitat cover, and soil properties. Datasets were required, at a minimum, to include abundance or biomass of earthworms at a site. Where possible, site-level species lists were included, as well as the abundance and biomass of individual species and ecological groups. This global dataset contains 10,840 sites, with 184 species, from 60 countries and all continents except Antarctica. The data were obtained from 182 published articles, published between 1973 and 2017, and 17 unpublished datasets. Amalgamating data into a single global database will assist researchers in investigating and answering a wide variety of pressing questions, for example, jointly assessing aboveground and belowground biodiversity distributions and drivers of biodiversity change.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41597-021-00912-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8140120PMC
May 2021

Multiple climate-driven cascading ecosystem effects after the loss of a foundation species.

Sci Total Environ 2021 May 25;770:144749. Epub 2021 Jan 25.

Stazione Zoologica Anton Dohrn, Dipartimento Ecologia Marina Integrata, Sicily Marine Centre, Lungomare Cristoforo Colombo (complesso Roosevelt), 90142 Palermo, Italy.

Climate change is evolving so fast that the related adverse effects on the environment are becoming noticeable. Thus, there is an urgent need to explore and understand the effects generated by multiple extreme climatic events (MECEs) on marine ecosystem functioning and the services provided. Accordingly, we combined long-term in-situ empirical observations in the Mediterranean Sea with a mesocosm manipulation to investigate the concurrence of increasing temperature and hypoxia events. By focussing on a foundation mussel species, we were able to detect several cascade events triggered by a mass mortality event caused by stressful temperature and oxygen conditions, and resulting in a loss of ecosystem services. The measured rates of chlorophyll-a, carbohydrates, proteins and lipids - in both particulate and sedimentary organic matter - were used as proxies of ecosystem functioning during pre- and post- disturbance events (MECEs). In the past, MECEs were crucial for individual performance, mussel population dynamics and biomass. Their effect propagated along the ecological hierarchy negatively affecting the associated community and ecosystem. Our results suggest that the protection and/or restoration of coastal areas requires careful consideration of ecosystem functioning. SIGNIFICANCE STATEMENT: Our decadal time-series recorded by a near-term ecological forecasting network of thermal sensor allowed us to record and monitor multiple extreme climatic events (MECEs; heat wave and hypoxia events), warning on the environmental change recorded on a pond system. By integrating observational and manipulative approaches, we showed how a MECE triggered cascade events, from individual-based impaired functioning up to biodiversity loss (community composition and structure changes). Our results emphasize the key role played by a foundation species in driving ecosystem functioning, and the synergistic effects of climatic drivers acting simultaneously.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.scitotenv.2020.144749DOI Listing
May 2021

Beyond virology: environmental constraints of the first wave of COVID-19 cases in Italy.

Environ Sci Pollut Res Int 2021 Jun 23;28(24):31996-32004. Epub 2021 Feb 23.

Department of Biological, Geological and Environmental Sciences, University of Catania, Via Androne 81, 95124, Catania, Italy.

Global warming and air pollution affect the transmission pathway and the survival of viruses, altering the human immune system as well. The first wave of the COVID-19 pandemic dramatically highlights the key roles of climate and air chemistry in viral epidemics. The elongated form of the Italian peninsula and the two major islands (the largest in Europe) is a perfect case study to assess some of these key roles, as the fate of the virus is mirroring the industrialization in the continental part of our country. Fine particulate matter (PM), geography, and climate explain what is happening in Italy and support cleaner air actions to address efficiently other outbreaks. Besides the environmental factors, future works should also address the genetic difference among individuals to explain the spatial variability of the human response to viral infections.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11356-021-12878-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7900802PMC
June 2021

Testing for top-down cascading effects in a biomass-driven ecological network of soil invertebrates.

Ecol Evol 2020 Jul 18;10(14):7062-7072. Epub 2020 Jun 18.

Department of Biological, Geological and Environmental Sciences University of Catania Catania Italy.

To investigate the structural changes of a food-web architecture, we considered real data coming from a soil food web in one abandoned pasture with former low-pressure agriculture management and we reproduced the corresponding ecological network within a multi-agent fully programmable modeling environment in order to simulate dynamically the cascading effects due to the removal of entire functional guilds.We performed several simulations differing from each other for the functional implications. At the first trophic level, we simulated a removal of the prey, that is, herbivores and microbivores, while at the second trophic level, we simulated a removal of the predators, that is, omnivores and carnivores. The five main guilds were removed either separately or in combination.The alteration in the food-web architecture induced by the removal of entire functional guilds was the highest when the entire second trophic level was removed, while the removal of all microbivores caused an alteration in the food-web structure of less than 5% of the total changes due to the removal of opportunistic and predatory species.Omnivores alone account for the highest shifts in time of the numerical abundances of the remaining species, providing computational evidence of the importance of the degree of omnivory in the stabilization of soil biota.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ece3.6408DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7391537PMC
July 2020

A global database of soil nematode abundance and functional group composition.

Sci Data 2020 03 26;7(1):103. Epub 2020 Mar 26.

J. F. Blumenbach Institute of Zoology and Anthropology, University of Göttingen, Göttingen, Germany.

As the most abundant animals on earth, nematodes are a dominant component of the soil community. They play critical roles in regulating biogeochemical cycles and vegetation dynamics within and across landscapes and are an indicator of soil biological activity. Here, we present a comprehensive global dataset of soil nematode abundance and functional group composition. This dataset includes 6,825 georeferenced soil samples from all continents and biomes. For geospatial mapping purposes these samples are aggregated into 1,933 unique 1-km pixels, each of which is linked to 73 global environmental covariate data layers. Altogether, this dataset can help to gain insight into the spatial distribution patterns of soil nematode abundance and community composition, and the environmental drivers shaping these patterns.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41597-020-0437-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7099023PMC
March 2020

Towards an integrative understanding of soil biodiversity.

Biol Rev Camb Philos Soc 2020 04 15;95(2):350-364. Epub 2019 Nov 15.

Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Uusimaa, Finland.

Soil is one of the most biodiverse terrestrial habitats. Yet, we lack an integrative conceptual framework for understanding the patterns and mechanisms driving soil biodiversity. One of the underlying reasons for our poor understanding of soil biodiversity patterns relates to whether key biodiversity theories (historically developed for aboveground and aquatic organisms) are applicable to patterns of soil biodiversity. Here, we present a systematic literature review to investigate whether and how key biodiversity theories (species-energy relationship, theory of island biogeography, metacommunity theory, niche theory and neutral theory) can explain observed patterns of soil biodiversity. We then discuss two spatial compartments nested within soil at which biodiversity theories can be applied to acknowledge the scale-dependent nature of soil biodiversity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/brv.12567DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7078968PMC
April 2020

Global distribution of earthworm diversity.

Science 2019 10;366(6464):480-485

Asian School of the Environment, Nanyang Technological University, 639798 Singapore.

Soil organisms, including earthworms, are a key component of terrestrial ecosystems. However, little is known about their diversity, their distribution, and the threats affecting them. We compiled a global dataset of sampled earthworm communities from 6928 sites in 57 countries as a basis for predicting patterns in earthworm diversity, abundance, and biomass. We found that local species richness and abundance typically peaked at higher latitudes, displaying patterns opposite to those observed in aboveground organisms. However, high species dissimilarity across tropical locations may cause diversity across the entirety of the tropics to be higher than elsewhere. Climate variables were found to be more important in shaping earthworm communities than soil properties or habitat cover. These findings suggest that climate change may have serious implications for earthworm communities and for the functions they provide.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1126/science.aax4851DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7335308PMC
October 2019

Soil nematode abundance and functional group composition at a global scale.

Nature 2019 08 24;572(7768):194-198. Epub 2019 Jul 24.

Department of Terrestrial Ecology, Netherlands Institute of Ecology, Wageningen, The Netherlands.

Soil organisms are a crucial part of the terrestrial biosphere. Despite their importance for ecosystem functioning, few quantitative, spatially explicit models of the active belowground community currently exist. In particular, nematodes are the most abundant animals on Earth, filling all trophic levels in the soil food web. Here we use 6,759 georeferenced samples to generate a mechanistic understanding of the patterns of the global abundance of nematodes in the soil and the composition of their functional groups. The resulting maps show that 4.4 ± 0.64 × 10 nematodes (with a total biomass of approximately 0.3 gigatonnes) inhabit surface soils across the world, with higher abundances in sub-Arctic regions (38% of total) than in temperate (24%) or tropical (21%) regions. Regional variations in these global trends also provide insights into local patterns of soil fertility and functioning. These high-resolution models provide the first steps towards representing soil ecological processes in global biogeochemical models and will enable the prediction of elemental cycling under current and future climate scenarios.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41586-019-1418-6DOI Listing
August 2019

Predator traits determine food-web architecture across ecosystems.

Nat Ecol Evol 2019 06 20;3(6):919-927. Epub 2019 May 20.

Estación Costera de Investigaciones Marinas, Las Cruces, LINCGlobal, Center for Applied Ecology and Sustainability (CAPES), Pontificia Universidad Católica de Chile, Santiago, Chile.

Predator-prey interactions in natural ecosystems generate complex food webs that have a simple universal body-size architecture where predators are systematically larger than their prey. Food-web theory shows that the highest predator-prey body-mass ratios found in natural food webs may be especially important because they create weak interactions with slow dynamics that stabilize communities against perturbations and maintain ecosystem functioning. Identifying these vital interactions in real communities typically requires arduous identification of interactions in complex food webs. Here, we overcome this obstacle by developing predator-trait models to predict average body-mass ratios based on a database comprising 290 food webs from freshwater, marine and terrestrial ecosystems across all continents. We analysed how species traits constrain body-size architecture by changing the slope of the predator-prey body-mass scaling. Across ecosystems, we found high body-mass ratios for predator groups with specific trait combinations including (1) small vertebrates and (2) large swimming or flying predators. Including the metabolic and movement types of predators increased the accuracy of predicting which species are engaged in high body-mass ratio interactions. We demonstrate that species traits explain striking patterns in the body-size architecture of natural food webs that underpin the stability and functioning of ecosystems, paving the way for community-level management of the most complex natural ecosystems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41559-019-0899-xDOI Listing
June 2019

How soil granulometry, temperature, and water predict genetic differentiation in Namibian spiders (: Segestriidae) and explain their behavior.

Ecol Evol 2019 Apr 28;9(8):4382-4391. Epub 2019 Mar 28.

Department of Biological, Geological and Environmental Sciences University of Catania Catania Italy.

The Namib Desert is a biodiversity hotspot for many invertebrates, including spiders. Tube-dwelling spiders belonging to the genus are widespread in gravel plains. These sit-and-wait predators share a particular behavior, as they spend their life in tunnels in the soil, surrounding the entrance of their burrow with stone rings. We investigated five spider populations taking into account environmental parameters, functional traits, and molecular data. We have chosen the temperature at the soil surface and at the bottom of the burrow, the air humidity, and the soil granulometry to define the environment. The chosen functional traits were the diameter and depth of the burrows, the ratio between weight and length, the thermal properties of their silks, and the number of ring elements. The molecular branch lengths and the evolutionary distance emerging from cytochrome oxidase I gene sequences summarized the molecular analysis. Our study highlights a strong coherence between the resulting evolutionary lineages and the respective geographical distribution. Multivariate analyses of both environmental and molecular data provide the same phylogenetic interpretation. Low intrapopulation sequence divergence and the high values between population sequence divergence (between 4.9% and 26.1%) might even suggest novel taxa which deserve further investigation. We conclude that both the Kimura distance and the branch lengths are strengthening the environmental clustering of these peculiar sites in Namibia.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ece3.4929DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6476775PMC
April 2019

Unifying the functional diversity in natural and cultivated soils using the overall body-mass distribution of nematodes.

BMC Ecol 2017 Nov 28;17(1):36. Epub 2017 Nov 28.

National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.

Background: Sustainable use of our soils is a key goal for environmental protection. As many ecosystem services are supported belowground at different trophic levels by nematodes, soil nematodes are expected to provide objective metrics for biological quality to integrate physical and chemical soil variables. Trait measurements of body mass carried out at the individual level can in this way be correlated with environmental properties that influence the performance of soil biota.

Results: Soil samples were collected across 200 sites (4 soil types and 5 land-use types resulting in 9 combinations) during a long-term monitoring programme in the Netherlands and the functional diversity of nematode communities was investigated. Using three commonly used functional diversity indices applicable to single traits (Divergence, Evenness and Richness), a unified index of overall body-mass distribution is proposed to better illustrate the application of functional metrics as a descriptor of land use. Effects of land use and soil chemistry on the functional diversity of nematodes were demonstrated and a combination of environmental factors accounts for the low functional value of Scots Pine forest soils in comparison to the high functional value of heathland soils, whereas human factors account for the low functional and chemical values of arable fields.

Conclusions: These findings show an unexpected high functional vulnerability of nematodes inhabiting clay-rich soils in comparison to sandy soils and support the notion that soil C:N ratio is a major driver of biodiversity. The higher the C:N ratio, the higher the overall diversity, as soil nematodes cope better with nutrient-poor agroecosystems under less intense fertilization. A trait-based way focusing on size distribution of nematodes is proposed to maintain environmental health by monitoring the overall diversity in soil biota, keeping agriculture and forestry sustainable.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12898-017-0145-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5706308PMC
November 2017

Pathogenic helminths in the past: Much ado about nothing.

Authors:
Christian Mulder

F1000Res 2017 8;6:852. Epub 2017 Jun 8.

National Institute for Public Health and the Environment (RIVM), Bilthoven, 3721, Netherlands.

Despite a long tradition on the extent to which Romanisation has improved human health, some recent studies suggest that Romanisation in general, and Roman sanitation in particular, may not have made people any healthier, given that in Roman times gastrointestinal parasites were apparently widespread, whilst in the present day such parasites rarely cause diseases. Unfortunately, this novel claim neglects the empirical evidence that worldwide infections in over 1.5 billion people are caused by ubiquitous foodborne nematodes. Therefore, many may wonder if fossil remains of soil-transmitted helminths have been reported in ancient sanitation infrastructures. Beneficial access to improved sanitation should always be prioritized, hence how can historical sanitation efforts have ever been harmful? In this short article, a strong plea for caution is given, asking for an augmented nematological record and showing that there is not any evidence against Roman sanitation, neither in the past nor in the present.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.12688/f1000research.11752.3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5580415PMC
June 2017

Identification and ranking of environmental threats with ecosystem vulnerability distributions.

Sci Rep 2017 08 24;7(1):9298. Epub 2017 Aug 24.

Department of Sustainability, Environment and Health, National Institute for Public Health and the Environment, P.O. Box 1, 3720, BA, Bilthoven, The Netherlands.

Responses of ecosystems to human-induced stress vary in space and time, because both stressors and ecosystem vulnerabilities vary in space and time. Presently, ecosystem impact assessments mainly take into account variation in stressors, without considering variation in ecosystem vulnerability. We developed a method to address ecosystem vulnerability variation by quantifying ecosystem vulnerability distributions (EVDs) based on monitoring data of local species compositions and environmental conditions. The method incorporates spatial variation of both abiotic and biotic variables to quantify variation in responses among species and ecosystems. We show that EVDs can be derived based on a selection of locations, existing monitoring data and a selected impact boundary, and can be used in stressor identification and ranking for a region. A case study on Ohio's freshwater ecosystems, with freshwater fish as target species group, showed that physical habitat impairment and nutrient loads ranked highest as current stressors, with species losses higher than 5% for at least 6% of the locations. EVDs complement existing approaches of stressor assessment and management, which typically account only for variability in stressors, by accounting for variation in the vulnerability of the responding ecosystems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-017-09573-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5571148PMC
August 2017

Feeding preference as a main determinant of microscale patchiness among terrestrial nematodes.

Mol Ecol Resour 2017 Nov 21;17(6):1257-1270. Epub 2017 Apr 21.

Laboratory of Nematology, Wageningen University and Research Centre (WUR), Wageningen, The Netherlands.

Soil biota are responsible for essential ecosystem services such as carbon storage, nutrient cycling and water retention. However, assessment of the condition of soil biota is hampered by an overwhelming level of diversity. With representatives in all trophic levels of the food web, nematode communities can be used as bioindicators. Accurate assessment of nematode assemblages requires insight into the distribution of specimens with distinct food preferences. With the availability of taxon-specific quantitative PCR assays, distribution patterns of multiple nematode groups can be investigated simultaneously. Here, microscale patchiness of 45 nematode taxa was studied on 12 sampling sites (each with four adjacent microplots) located on arable fields or semi-natural grasslands ('system'), and on marine, river clay or sandy soils ('soil type'). From each microplot, five composite samples were collected. Contrary to our expectations, an increase in the number of cores per composite sample did not result in more accurate measurements, and apparently the levels of microscale patchiness of the taxa are low compared to what has been reported for oligophagous plant-parasites. System and soil type did not affect microscale distribution. To investigate the level of patchiness in more detail, detection probability (DP) and variability of abundances were calculated. Common and widespread bacterivorous and fungivorous taxa had DP ≥ 90%, confirming low level of microscale patchiness. With DPs of 40%-70%, predators and most omnivores showed degrees of local clustering. An overview of mean variabilities of abundances is presented that offers insight into how feeding preferences impact the microscale distribution both between and within trophic groups.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/1755-0998.12672DOI Listing
November 2017

Pack hunting by a common soil amoeba on nematodes.

Environ Microbiol 2015 Nov 28;17(11):4538-46. Epub 2015 Jul 28.

Department of Terrestrial Ecology, Institute of Zoology, University of Cologne, Cologne, Germany.

Soils host the most complex communities on Earth, including the most diverse and abundant eukaryotes, i.e. heterotrophic protists. Protists are generally considered as bacterivores, but evidence for negative interactions with nematodes both from laboratory and field studies exist. However, direct impacts of protists on nematodes remain unknown. We isolated the soil-borne testate amoeba Cryptodifflugia operculata and found a highly specialized and effective pack-hunting strategy to prey on bacterivorous nematodes. Enhanced reproduction in presence of prey nematodes suggests a beneficial predatory life history of these omnivorous soil amoebae. Cryptodifflugia operculata appears to selectively impact the nematode community composition as reductions of nematode numbers were species specific. Furthermore, we investigated 12 soil metatranscriptomes from five distinct locations throughout Europe for 18S ribosomal RNA transcripts of C. operculata. The presence of C. operculata transcripts in all samples, representing up to 4% of the active protist community, indicates a potential ecological importance of nematophagy performed by C. operculata in soil food webs. The unique pack-hunting strategy on nematodes that was previously unknown from protists, together with molecular evidence that these pack hunters are likely to be abundant and widespread in soils, imply a considerable importance of the hitherto neglected trophic link 'nematophagous protists' in soil food webs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/1462-2920.12949DOI Listing
November 2015

Resource niche overlap promotes stability of bacterial community metabolism in experimental microcosms.

Front Microbiol 2015 24;6:105. Epub 2015 Feb 24.

Department of Aquatic Ecology and Ecotoxicology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam Amsterdam, Netherlands.

Decomposition of organic matter is an important ecosystem process governed in part by bacteria. The process of decomposition is expected to benefit from interspecific bacterial interactions such as resource partitioning and facilitation. However, the relative importance of resource niche breadth (metabolic diversity) and resource niche overlap (functional redundancy) on decomposition and the temporal stability of ecosystem processes received little scientific attention. Therefore, this study aims to evaluate the effect of an increase in bacterial community resemblance on both decomposition and the stability of bacterial metabolism in aquatic sediments. To this end, we performed laboratory microcosm experiments in which we examined the influence of bacterial consortia differing in number and composition of species on bacterial activity (Electron Transport System Activity, ETSA), dissolved organic carbon production and wavelet transformed measurements of redox potential (Eh). Single substrate affinities of the individual bacterial species were determined in order to calculate the metabolic diversity of the microbial community. Results presented here indicate that bacterial activity and organic matter decomposition increase with widening of the resource niche breadth, and that metabolic stability increases with increasing overlap in bacterial resource niches, hinting that resource niche overlap can promote the stability of bacterial community metabolism.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fmicb.2015.00105DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4338809PMC
March 2015

Choice of resolution by functional trait or taxonomy affects allometric scaling in soil food webs.

Am Nat 2015 Jan 19;185(1):142-9. Epub 2014 Nov 19.

National Institute for Public Health and the Environment, 3720BA Bilthoven, The Netherlands.

Belowground organisms often display a shift in their mass-abundance scaling relationships due to environmental factors such as soil chemistry and atmospheric deposition. Here we present new empirical data that show strong differences in allometric scaling according to whether the resolution at the local scale is based on a taxonomic or a functional classification, while only slight differences arise according to soil environmental conditions. For the first time, isometry (an inverse 1:1 proportion) is recognized in mass-abundance relationships, providing a functional signal for constant biomass distribution in soil biota regardless of discrete trophic levels. Our findings are in contrast to those from aquatic ecosystems, in that higher trophic levels in soil biota are not a direct function of increasing body mass.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1086/678962DOI Listing
January 2015

Chemical footprints: thin boundaries support environmental quality management.

Environ Sci Technol 2014 Nov 29;48(22):13025-6. Epub 2014 Oct 29.

RIVM, Centre for Sustainability, Environment and Health , P.O. Box 1, 3720BA Bilthoven, The Netherlands.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/es505004nDOI Listing
November 2014

Beyond safe operating space: finding chemical footprinting feasible.

Environ Sci Technol 2014 Jun 21;48(11):6057-9. Epub 2014 May 21.

RIVM , Centre for Sustainability, Environment and Health, P.O. Box 1, 3720BA Bilthoven, The Netherlands.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/es501961kDOI Listing
June 2014

Contrasting influence of soil nutrients and microbial community on differently sized basal consumers.

Naturwissenschaften 2013 Jul 24;100(7):611-20. Epub 2013 May 24.

Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam 1090GE, The Netherlands.

There is increasing evidence of the coexistence of trophic and environmental constraints belowground. While too often ignored in current literature, the extent to which phosphorus is relevant for soil biota was demonstrated in this study by positive correlations of soil C/P and N/P ratios with all the measured microbial parameters (biomass, density and activity), with the numerical abundance of roundworms (Nematoda) and potworms (Enchytraeidae) from lower trophic levels and with the roundworm biomass. Total worm biomass seems dependent on land use, being in rangelands about twice as high as in croplands, although the relative contribution of potworms remains comparable for both land use types (49 ± 20 % SD versus 45 ± 27 % SD). Besides soil [P], soil type plays an important role in the relative biomass of potworms compared to roundworms. Soil parameters (here pH, C/P and N/P ratios) are better predictors for the abundance and biomass of roundworms than microbial parameters. We also propose a graphical way to visualize the major responses of basal consumers to their microbial drivers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00114-013-1058-xDOI Listing
July 2013

The practicalities and pitfalls of establishing a policy-relevant and cost-effective soil biological monitoring scheme.

Integr Environ Assess Manag 2013 Apr;9(2):276-84

Alterra, Wageningen UR, Wageningen, The Netherlands.

A large number of biological indicators have been proposed over the years for assessing soil quality. Although many of those have been applied in monitoring schemes across Europe, no consensus exists on the extent to which these indicators might perform best and how monitoring schemes can be further optimized in terms of scientific and policy relevance. Over the past decade, developments in environmental monitoring and risk assessment converged toward the use of indicators and endpoints that are related to soil functioning and ecosystem services. In view of the proposed European Union (EU) Soil Framework Directive, there is an urgent need to identify and evaluate indicators for soil biodiversity and ecosystem services. The recently started integrated project, Ecological Function and Biodiversity Indicators in European Soils (EcoFINDERS), aims to address this specific issue within the EU Framework Program FP7. Here, we 1) discuss how to use the concept of ecosystem services in soil monitoring, 2) review former and ongoing monitoring schemes, and 3) present an analysis of metadata on biological indicators in some EU member states. Finally, we discuss our experiences in establishing a logical sieve approach to devise a monitoring scheme for a standardized and harmonized application at European scale.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ieam.1398DOI Listing
April 2013

SSU ribosomal DNA-based monitoring of nematode assemblages reveals distinct seasonal fluctuations within evolutionary heterogeneous feeding guilds.

PLoS One 2012 24;7(10):e47555. Epub 2012 Oct 24.

Laboratory of Nematology, Department of Plant Sciences, Wageningen University, WUR, Wageningen, The Netherlands.

Soils are among the most complex, diverse and competitive habitats on Earth and soil biota are responsible for ecosystem services such as nutrient cycling, carbon sequestration and remediation of freshwater. The extreme biodiversity prohibits the making of a full inventory of soil life. Hence, an appropriate indicator group should be selected to determine the biological condition of soil systems. Due to their ubiquity and the diverse responses to abiotic and biotic changes, nematodes are suitable indicators for environmental monitoring. However, the time-consuming microscopic analysis of nematode communities has limited the scale at which this indicator group is used. In an attempt to circumvent this problem, a quantitative PCR-based tool for the detection of a consistent part of the soil nematofauna was developed based on a phylum-wide molecular framework consisting of 2,400 full-length SSU rDNA sequences. Taxon-specific primers were designed and tested for specificity. Furthermore, relationships were determined between the quantitative PCR output and numbers of target nematodes. As a first field test for this DNA sequence signature-based approach, seasonal fluctuations of nematode assemblages under open canopy (one field) and closed canopy (one forest) were monitored. Fifteen taxa from four feeding guilds (covering ∼ 65% of the free-living nematode biodiversity at higher taxonomical level) were detected at two trophic levels. These four feeding guilds are composed of taxa that developed independently by parallel evolution and we detected ecologically interpretable patterns for free-living nematodes belonging to the lower trophic level of soil food webs. Our results show temporal fluctuations, which can be even opposite within taxa belonging to the same guild. This research on nematode assemblages revealed ecological information about the soil food web that had been partly overlooked.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0047555PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3480422PMC
April 2013

Trait-mediated diversification in nematode predator-prey systems.

Ecol Evol 2011 Nov;1(3):386-91

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 the predatory juveniles. Potential body size ratios and some physical problems experienced by small fluid feeders attacking large prey are discussed in an attempt to summarize different prey-searching mechanisms and aggregative predatory responses in the soil system.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ece3.36DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3287312PMC
November 2011

World Wide Food Webs: power to feed ecologists.

Authors:
Christian Mulder

Ambio 2011 May;40(3):335-7

National Institute for Public Health and Environment (RIVM), Bilthoven, Netherland.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3357800PMC
http://dx.doi.org/10.1007/s13280-010-0069-5DOI Listing
May 2011

Soil fertility controls the size-specific distribution of eukaryotes.

Authors:
Christian Mulder

Ann N Y Acad Sci 2010 May;1195 Suppl 1:E74-81

National Institute for Public Health and the Environment, RIVM-LER, Bilthoven, the Netherlands.

The large range of body-mass values of soil organisms provides a tool to assess the organization of soil ecological communities. Relationships between log-transformed body mass M and log-transformed numerical abundance N of all eukaryotes occurring under organic pastures, mature grasslands, and seminatural heathlands in the Netherlands were investigated. The observed allometry of (M,N) assemblages of below-ground communities strongly reflects the availability of primary macronutrients and essential micronutrients. This log-linear model describes the continuous variation in the allometric slope of animals and fungi along an increasing soil fertility gradient. The aggregate contribution of small invertebrates (M < 1 microg) to the entire faunal community is highest under nutrient deficiency and causes shifts in the mass-abundance relationships. The phosphorus concentration in the soil explains 72% of these shifts but the nitrogen concentration explains only 36%, with copper and zinc as intermediate predictors (59% and 49%, respectively). Empirical evidence supports common responses of invertebrates to the rates of resource supply and, possibly, to the above-ground primary production of ecosystems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1749-6632.2009.05404.xDOI Listing
May 2010

Soil resource supply influences faunal size-specific distributions in natural food webs.

Naturwissenschaften 2009 Jul 14;96(7):813-26. Epub 2009 May 14.

Department of Ecology, National Institute for Public Health and the Environment, Box 1, Bilthoven, 3720 BA, The Netherlands.

The large range of body-mass values of soil organisms provides a tool to assess the ecological organization of soil communities. The goal of this paper is to identify graphical and quantitative indicators of soil community composition and ecosystem functioning, and to illustrate their application to real soil food webs. The relationships between log-transformed mass and abundance of soil organisms in 20 Dutch meadows and heathlands were investigated. Using principles of allometry, maximal use can be made of ecological theory to build and explain food webs. The aggregate contribution of small invertebrates such as nematodes to the entire community is high under low soil phosphorus content and causes shifts in the mass-abundance relationships and in the trophic structures. We show for the first time that the average of the trophic link lengths is a reliable predictor for assessing soil fertility responses. Ordered trophic link pairs suggest a self-organizing structure of food webs according to resource availability and can predict environmental shifts in ecologically meaningful ways.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00114-009-0539-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2705724PMC
July 2009

Aboveground herbivory shapes the biomass distribution and flux of soil invertebrates.

PLoS One 2008 31;3(10):e3573. Epub 2008 Oct 31.

Department of Ecology, National Institute for Public Health and the Environment, RIVM-LER, Bilthoven, The Netherlands.

Background: Living soil invertebrates provide a universal currency for quality that integrates physical and chemical variables with biogeography as the invertebrates reflect their habitat and most ecological changes occurring therein. The specific goal was the identification of "reference" states for soil sustainability and ecosystem functioning in grazed vs. ungrazed sites.

Methodology/principal Findings: Bacterial cells were counted by fluorescent staining and combined direct microscopy and automatic image analysis; invertebrates (nematodes, mites, insects, oligochaetes) were sampled and their body size measured individually to allow allometric scaling. Numerical allometry analyses food webs by a direct comparison of weight averages of components and thus might characterize the detrital soil food webs of our 135 sites regardless of taxonomy. Sharp differences in the frequency distributions are shown. Overall higher biomasses of invertebrates occur in grasslands, and all larger soil organisms differed remarkably.

Conclusions/significance: Strong statistical evidence supports a hypothesis explaining from an allometric perspective how the faunal biomass distribution and the energetic flux are affected by livestock, nutrient availability and land use. Our aim is to propose faunal biomass flux and biomass distribution as quantitative descriptors of soil community composition and function, and to illustrate the application of these allometric indicators to soil systems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0003573PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2570614PMC
February 2009

Three allometric relations of population density to body mass: theoretical integration and empirical tests in 149 food webs.

Ecol Lett 2008 Nov 17;11(11):1216-1228. Epub 2008 Sep 17.

Laboratory of Populations, Rockefeller University, 1230 York Avenue, Box 20, New York, NY 10065, USADepartment of Ecology, RIVM, 9 Antonie van Leeuwenhoeklaan, Box 1, Bilthoven 3720 BA, The NetherlandsEnvironment Department, University of York, York YO10 5DD, UK.

Predicting species population density-body mass scaling in community food webs (henceforth webs) is important for conservation and to understand community structure. Very different types of scaling have been studied, based on either individuals or species. The individual size distribution (ISD) describes the distribution of individual-organism body masses regardless of taxonomy, and contains the same information as the abundance spectrum. Focusing instead on species, the local size-density relationship (LSDR) plots population densities vs. mean body masses of species. The distribution of species mean body masses (the species-mean-size distribution, SMSD) is also important but previously little studied in webs. We here combine and formalize theory of several authors to predict: how these three descriptions are related; the forms of the LSDR and ISD; and variation in scaling among webs. We describe empirically the SMSDs of two pelagic, one estuarine, and 146 soil webs by power laws and generalizations. We test theory and find it broadly validated.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1461-0248.2008.01236.xDOI Listing
November 2008

Scaling of offspring number and mass to plant and animal size: model and meta-analysis.

Oecologia 2008 Apr 15;155(4):705-16. Epub 2008 Jan 15.

Department of Environmental Science, Radboud University Nijmegen, PO Box 9010, 6500 GL, Nijmegen, The Netherlands.

The scaling of reproductive parameters to body size is important for understanding ecological and evolutionary patterns. Here, we derived allometric relationships for the number and mass of seeds, eggs and neonates from an existing model on population production. In a separate meta-analysis, we collected 79 empirical regressions on offspring mass and number covering different taxa and various habitats. The literature review served as a validation of the model, whereas, vice versa, consistency of isolated regressions with each other and related ecological quantities was checked with the model. The total offspring mass delivered in a reproductive event scaled to adult size with slopes in the range of about 3/4 to 1. Exponents for individual seed, egg and neonate mass varied around 1/2 for most heterotherms and between 3/4 and 1 for most homeotherms. The scaling of the progeny number released in a sowing, clutch or litter was opposite to that of their size. The linear regressions fitted into a triangular envelope where maximum offspring mass is limited by the size of the adult. Minimum seed and egg size scaled with weight exponents of approximately 0 up to 1/4. These patterns can be explained by the influence of parents on the fate of their offspring, covering the continuum of r-strategists (pelagic-aquatic, arial, most invertebrates, heterotherms) and K-strategists (littoral-terrestrial, some invertebrates, homeotherms).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00442-007-0952-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2270366PMC
April 2008

Age structure and senescence in long-term cohorts of Eisenia andrei (Oligochaeta: Lumbricidae).

J Gerontol A Biol Sci Med Sci 2007 Dec;62(12):1361-3

National Institute for Public Health and the Environment, Bilthoven, The Netherlands.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/gerona/62.12.1361DOI Listing
December 2007
-->