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Struijs J.,Laboratory for Ecological Risk Assessment LER Pb 9 | De Zwart D.,Laboratory for Ecological Risk Assessment LER Pb 9 | Posthuma L.,Laboratory for Ecological Risk Assessment LER Pb 9 | Leuven R.S.E.W.,Radboud University Nijmegen | Huijbregts M.A.J.,Radboud University Nijmegen
Integrated Environmental Assessment and Management | Year: 2011

The magnitude of ecological damage caused by elevated phosphorus concentrations (CP) in Dutch inland waters is expressed as the fraction of disappeared macroinvertebrate genera. We used field observations of species occurrence from 1980 to 2005 that were stored in the Limnodata Neerlandica to derive the presence of 867 aquatic macroinvertebrate genera in the water column of freshwater bodies with total phosphorus (Ptot) concentrations ranging from 0.001 to 40 mg/L. At concentrations>0.3 mg/L, which is considered to cause nutrient enrichment of freshwater bodies, the disappeared fraction (DF) of macroinvertebrate genera can be described as a logistic function of the CP: DF=1/(1+4.07/C1:1.11 P). The logistic function suggests that half of the macroinvertebrate genera that potentially occur in the freshwater column in the Netherlands would disappear at a CP=3.5 mg/L. This field-based effect expression resembles the cumulative sensitivity distribution function for a toxic substance based on the species sensitivity distribution (SSD) concept and exposure data. Whereas an SSD for a toxic chemical is derived from laboratory sensitivity data for a small number of species, our DF is derived from field observations of many macroinvertebrate genera at numerous CP levels. By applying this damage function to measured phosphorus in the rivers Rhine, Meuse, and Scheldt, we found that the observed CP values in 1975 imply diversity losses of 15% for the Rhine and Meuse, and 20% for the Scheldt. For 2000, the calculated diversity losses are 3%(Rhine), 6%(Meuse), and9% (Scheldt). The cumulative genera sensitivity distribution function for phosphorus from national freshwater monitoring data can be applied in various environmental screening systems, such as multistress impact assessment of surface waters, and in life cycle impact assessment of products. © 2010 SETAC. Source

Azevedo L.B.,Radboud University Nijmegen | van Zelm R.,Radboud University Nijmegen | Elshout P.M.F.,Radboud University Nijmegen | Hendriks A.J.,Radboud University Nijmegen | And 4 more authors.
Global Ecology and Biogeography | Year: 2013

Aim: We investigated the patterns of autotrophic and heterotrophic relative species richness along a total phosphorus (TP) concentration gradient. The relative species richness-TP relationships were calculated separately for four different regions [(sub)tropical, xeric, temperate and cold] and two types of water bodies (lakes and streams). Location: Global Methods: Using data from peer-reviewed articles reporting the occurrence of freshwater species at specific TP concentrations, we determined the species richness along a TP gradient. Using log-logistic regressions, we then estimated the TP concentration at which the potential decrease of relative species richness (RSR) equals 0.5 and the slope at which the decrease occurs (β). The RSR is given as the ratio of species richness to maximized species richness along a TP gradient. Results: The RSR of streams generally decreased more rapidly than that of lakes with increasing P, as illustrated by the steeper slope of the log-logistic functions for streams (βlakes<βstreams). Although there was no consistent trend between autotrophs and heterotrophs in the different regions, we found that the TP concentration at which the RSR equals 0.5 was lower in cold regions (0.04-0.22mg P/L) than in warmer regions (0.28-1.29mg P/L). Main Conclusions: The log-logistic relationships between RSR and TP concentration vary considerably among regions of the world, between freshwater types (lakes and streams) and between species groups (autotrophs and heterotrophs). This variability may be attributed to differences between the two freshwater types in respect to their species groups and evolutionary patterns, nutrient demand, biogeochemical and hydrological processes. We were not able to derive log-logistic regressions for all combinations of freshwater type or species type and region [e.g. (sub)tropical lakes]. For other areas, our results can be used to assess the potential impact of phosphorus eutrophication on freshwater biota. © 2013 John Wiley & Sons Ltd. Source

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