Article

Assessment of structure and function in metal polluted grasslands using Terrestrial Model Ecosystems.

Department of Animal Ecology, Vrije Universiteit, Amsterdam, The Netherlands.
Ecotoxicology and Environmental Safety (Impact Factor: 2.2). 07/2008; 72(1):51-9. DOI: 10.1016/j.ecoenv.2008.03.016
Source: PubMed

ABSTRACT Ecosystem effects of metal pollution in field situations are hard to predict, since metals occur often in mixtures and links between structural (organisms) and functional endpoints (ecosystem processes) are not always that clear. In grasslands, both structure and functioning was suspected to be affected by a mixture of copper, lead, and zinc. Therefore, the structural and functional variables were studied simultaneously using Terrestrial Model Ecosystems (TMEs). Comparing averages of low- and high-polluted soil, based on total metal concentrations, did not show differences in structural and functional variables. However, nematode community structure (Maturity Index) negatively correlated with metal concentrations. Next to that, multivariate statistics showed that enchytraeid, earthworm and, to lesser extent, nematode diversity decreased with increasing metal concentrations and a lower pH in the soil. Bacterial CFU and nematode biomass were positively related with decomposer activity and nitrate concentrations. Nitrate concentrations were negatively related to ammonium concentrations. Earthworm biomass, CO(2) production and plant yield were not related to metal concentrations. The most metal-sensitive endpoint was enchytraeid biomass. In all analyses, soil pH was a significant factor, indicating direct effects on organisms, or indicating indirect effects by influencing metal availability. In general, structural diversity seemed more positively related to functional endpoints than structural biomass. TMEs proved valuable tools to assess the structure and function in metal polluted field situations. The outcome feeds modeling effort and direct future research.

0 Bookmarks
 · 
138 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this study the influence of metal pollution on soil functional activity was evaluated by means of Bait lamina and BIOLOG® EcoPlates™ assays. The in situ bait lamina assay investigates the feeding activity of macrofauna, mesofauna and microarthropods while the BIOLOG® EcoPlate™ assay measures the metabolic fingerprint of a selectively extracted microbial community. Both assays proved sensitive enough to reveal changes in the soil community between the plots nearest to and further away from a metal pollution source. Feeding activity (FA) at the less polluted plots reached percentages of 90% while plots nearer to the source of pollution reached percentages as low as 10%. After 2 and 6 days of incubation average well color development (AWCD) and functional richness (R′R′) were significantly lower at the plots closest to the source of pollution. While the Shannon Wiener diversity index (H′H′) decreased significantly at sites nearer to the source of pollution after 2 days but not after 6 days of incubation. Arsenic, Cu and Pb correlated significantly and negatively with feeding activity and functional indices while the role of changing environmental factors such as moisture percentage could not be ruled out completely. Compared to the Bait lamina method that is used in situ and which is therefore more affected by site specific variation, the BIOLOG assay, which excludes confounding factors such as low moisture percentage, may be a more reliable assay to measure soil functional activity.
    Environmental Research. 01/2014; 134:169–180.
  • [Show abstract] [Hide abstract]
    ABSTRACT: The responses of soil faunal communities to lead (Pb) contamination in a shooting range area and the recovery of these fauna after range abandonment were studied by comparing the communities at an active shotgun shooting range, an abandoned shooting range, and a control site, locating in the same forest. Despite the similar overall Pb pellet load at the shooting ranges, reaching up to 4 kg m(-2), Pb concentrations in the top soil of the abandoned range has decreased due to the accumulation of detritus on the soil surface. As a consequence, soil animal communities were shown to recover from Pb-related disturbances by utilizing the less contaminated soil layer. Microarthropods showed the clearest signs of recovery, their numbers and community composition being close to those detected at the control site. However, in the deepest organic soil layer, the negative effects of Pb were more pronounced at the abandoned than at the active shooting range, which was detected as altered microarthropod and nematode community structures, reduced abundances of several microarthropod taxa, and the total absence of enchytraeid worms. Thus, although the accumulation of fresh litter on soil surface can promote the recovery of decomposer communities in the top soil, the gradual release of Pb from corroding pellets may pose a long-lasting risk for decomposer taxa deeper in the soil.
    Ecotoxicology 02/2014; · 2.77 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Rapid ecosystem assessments are needed for large-scale ecotoxicological studies and coordinated distributed experiments. Bait-lamina stripes are commonly used as a standardized method to assess decomposer activity, but it is often difficult to distinguish bait substrate from soil. In the present study our aim was to identify a dyeing method that improves the precision of visual assessment of decomposition rates, while having negligible side effects. We compared five different dyes (food dye, Easter Grass, organic textile dye, ink, and wall paint) with control substrate in microcosms containing either acidic or alkaline soil with two introduced Collembola species (Folsomia candida and Sinellacoeca). Organic textile dye showed the highest precision of visual assessment, and had no detectable side effects on decomposition rates, soil microbial activity (biomass and respiration), or Collembola densities. We recommend using organic textile dye to improve the bait-lamina test due to the high precision and the ease of preparation.
    Applied Soil Ecology 01/2014; 82:78–81. · 2.11 Impact Factor

Full-text (3 Sources)

Download
91 Downloads
Available from
May 20, 2014