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Brogna D.,University of Namur | Michez A.,University of Liège | Jacobs S.,Research institute of nature and forest INBO | Dufrene M.,University of Liège | And 2 more authors.
Water (Switzerland) | Year: 2017

Forested catchments are generally assumed to provide higher quality water. However, this hypothesis must be validated in various contexts as interactions between multiple land use and land cover (LULC) types, ecological variables and water quality variables render this relationship highly complex. This paper applies a straightforward multivariate approach on a typical large monitoring dataset of a highly managed and densely populated area (Wallonia, Belgium; 10-year dataset), quantifying forest cover effects on nine physico-chemical water quality variables. Results show that forest cover explains about one third of the variability of water quality and is positively correlated with higher quality water. When controlling for spatial autocorrelation, forest cover still explains 9% of water quality. Unlike needle-leaved forest cover, broad-leaved forest cover presents an independent effect from ecological variables and explains independently 4.8% of water quality variability while it shares 5.8% with cropland cover. This study demonstrates clear independent effects of forest cover on water quality, and presents a method to tease out independent LULC effects from typical large multivariate monitoring datasets. Further research on explanatory variables, spatial distribution effects and water quality datasets could lead to effective strategies to mitigate pollution and reach legal targets. © 2017 by the authors.


Wasof S.,University of Picardie Jules Verne | Lenoir J.,University of Picardie Jules Verne | Aarrestad P.A.,Norwegian Institute for Nature Research | Alsos I.G.,University of Tromsø | And 49 more authors.
Global Ecology and Biogeography | Year: 2015

Aim: Previous research on how climatic niches vary across species ranges has focused on a limited number of species, mostly invasive, and has not, to date, been very conclusive. Here we assess the degree of niche conservatism between distant populations of native alpine plant species that have been separated for thousands of years. Location: European Alps and Fennoscandia. Methods: Of the studied pool of 888 terrestrial vascular plant species occurring in both the Alps and Fennoscandia, we used two complementary approaches to test and quantify climatic-niche shifts for 31 species having strictly disjunct populations and 358 species having either a contiguous or a patchy distribution with distant populations. First, we used species distribution modelling to test for a region effect on each species' climatic niche. Second, we quantified niche overlap and shifts in niche width (i.e. ecological amplitude) and position (i.e. ecological optimum) within a bi-dimensional climatic space. Results: Only one species (3%) of the 31 species with strictly disjunct populations and 58 species (16%) of the 358 species with distant populations showed a region effect on their climatic niche. Niche overlap was higher for species with strictly disjunct populations than for species with distant populations and highest for arctic-alpine species. Climatic niches were, on average, wider and located towards warmer and wetter conditions in the Alps. Main conclusion: Climatic niches seem to be generally conserved between populations that are separated between the Alps and Fennoscandia and have probably been so for 10,000-15,000 years. Therefore, the basic assumption of species distribution models that a species' climatic niche is constant in space and time - at least on time scales 104 years or less - seems to be largely valid for arctic-alpine plants. © 2015 John Wiley & Sons Ltd.


Van Praet N.,University of Antwerp | De Bruyn L.,University of Antwerp | De Bruyn L.,Research Institute of Nature and Forest INBO | De Jonge M.,University of Antwerp | And 3 more authors.
Aquatic Toxicology | Year: 2014

The present study measured various pesticides and trace metals, together with sublethal effect biomarkers (lipid, protein and glycogen levels, acetylcholinesterase (AChE) and glutathione-S-transferase (GST) activities) in damselfly larvae (Ischnura elegans) at sixteen sampling sites in Flanders (Belgium). Four pesticides (chloridazon, dichlorvos, terbutylazine, metolachlor), some of them hardly measurable in surface water, and all trace metals were above the limit of quantification in damselfly tissue. A principal component analysis (PCA) on the accumulated pollutant concentrations returned five pollutant axes explaining 85.8% of the total variation. Based on these PCA-axes a hierarchical cluster analysis revealed that the 16 sampled ponds could be classified in 7 groups. Increasing dichlorvos levels in the animals resulted in a lower body mass. Body mass was negatively correlated with GST and AChE activities, lipid and glycogen levels. The present findings provide evidence of toxicity-induced sublethal stress of dichlorvos accumulation in natural populations of I. elegans. © 2014 Elsevier B.V.


Jacobs S.,Research Institute of Nature and Forest INBO | Burkhard B.,University of Kiel | Burkhard B.,Leibniz Center for Agricultural Landscape Research | Van Daele T.,Research Institute of Nature and Forest INBO | And 2 more authors.
Ecological Modelling | Year: 2015

Ecosystem service research covers a challenging socio-ecological complexity and simultaneously copes with a high policy demand for decision support in sustainable resource management. This stimulates proliferation of pragmatic modeling techniques, such as the matrix model: ecosystem service supply is modeled using expert estimations per land use or land cover class. The matrix models popularity proves its main strengths (efficient, fast, accessible and adaptable), but also entails risks for scientific credibility and legitimacy of its results and ecosystem service assessments in general. Some of the main methodological critiques on the matrix model can be addressed especially by including measures of confidence, traceability, reliability, consistency and validity. This review presents recommendations and encourages these to become standard practise in future applications of the matrix model and related techniques.Additionally, we argue that an extended matrix model could provide more than only scientifically sound and politically legitimate results. It could serve as a tool to improve cooperation between natural and social sciences, experts, stakeholders and decision makers: collaborative development of the matrix model contributes to transdisciplinary ecosystem service research aimed at effective implementation and action. © 2014 Elsevier B.V.


Van Praet N.,University of Antwerp | Covaci A.,University of Antwerp | Teuchies J.,University of Antwerp | De Bruyn L.,University of Antwerp | And 4 more authors.
Science of the Total Environment | Year: 2012

We investigated the accumulation of persistent organic pollutants in damselfly larvae (Ischnura elegans) in sixteen ponds in Flanders (Belgium), widely differing in the surrounding land use. Concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) and hexachlorobenzene (HCB) were measured. From all targeted PBDE-congeners, only three congeners (IUPAC nos. 47, 99, 100) were above the limit of quantification (LOQ). The ∑PBDE concentrations ranged from LOQ (0.20ngg-1 ww) with values up to 3.30ngg-1 ww in the pond at Hamme. In fifteen ponds, the HCB concentrations were >LOQ (0.05ngg-1 ww) with values up to 0.24ngg-1 ww. For the available data in the literature a comparison with different species was done for some of the sampled ponds. The monitored ponds can be separated in three groups based on their contamination. The first group is characterised by a relative low POP content (∑PBDEs, ∑PCBs, HCB). Group 2 contained more HCB and p,p'-DDE than the overall mean while this was the case for PBDEs and PCBs in group 3. The vectors of both contaminated groups are situated nearly perpendicular which is suggesting a different pollution sources. © 2012 Elsevier B.V.

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