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- L. Kooistra (2)
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- H. Kroon de (1)
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- M. Scheffer (1)
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- J. Thissen (1)
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- E.J.W. Visser (2)
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- M. Wagenaar (1)
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- H.R.M.J. Wehrens (1)
- S. Wijnhoven (3)
- H. Wolters (1)
- M.I. Zorn (1)
Two approaches using traits to assess ecological resilience: A case study on earthworm communities
Lange, H.J. de; Kramer, K. ; Faber, J.H. - \ 2013
Basic and Applied Ecology 14 (2013)1. - ISSN 1439-1791 - p. 64 - 73.
river floodplains - species traits - wet grassland - biodiversity - diversity - macroinvertebrates - lumbricidae - oligochaeta - populations - pollutants
The relation between biological diversity and ecosystem functioning is a central theme in ecology. Ecological traits of species are often regarded as a link between structure and function, and trait distributions in a community may change in response to environmental stressors. Likewise, resilience in a community may be derived from the diversity in traits and trait values relevant to a particular stressor. We combine two approaches to test this: a novel trait frequency analysis and a multivariate ordination approach. The two methods are applied on a case study of an earthworm community in a frequently flooded floodplain in the Netherlands. Periodic flooding in floodplains restricts population growth and recolonization of earthworms. The strategies employed by different earthworm species for coping with this stress can be described by a combination of ecological traits. From the literature we compiled 10 ecological traits for the earthworm species encountered along an inundation gradient in the Duursche Waarden floodplain area flanking the river IJssel. Trait frequency analysis showed a greater diversity at low elevation sites of traits considered to be associated to flood tolerance, suggesting greater community resilience to flooding. The ordination analysis using trait composition provided information on which trait classes in the community were related with the inundation stress. Results from both analyses showed that important traits in species to deal with flooding are active dispersal, high hydrophily, diapause and parthenogenetic reproduction. Thus, a further understanding of community resilience was gained by combining traditional ordination analysis with trait diversity analysis
Contaminant exposure in relation to spatio-temporal variation in diet composition: A case study of the little owl (Athene noctua)
Schipper, A.M. ; Wijnhoven, S. ; Baveco, J.M. ; Brink, N.W. van den - \ 2012
Environmental Pollution 163 (2012). - ISSN 0269-7491 - p. 109 - 116.
river floodplains - small mammals - risk-assessment - cadmium accumulation - metal concentrations - food-chain - soil - predators - birds - heterogeneity
We assessed dietary exposure of the little owl Athene noctua to trace metal contamination in a Dutch Rhine River floodplain area. Diet composition was calculated per month for three habitat types, based on the population densities of six prey types (earthworms, ground beetles and four small mammal species) combined with the little owl’s functional response to these prey types. Exposure levels showed a strong positive relationship with the dietary fraction of earthworms, but also depended on the dietary fraction of common voles, with higher common vole fractions resulting in decreasing exposure levels. Spatio-temporal changes in the availability of earthworms and common voles in particular resulted in considerable variation in exposure, with peaks in exposure exceeding a tentative toxicity threshold. These findings imply that wildlife exposure assessments based on a predefined, average diet composition may considerably underestimate local or intermittent peaks in exposure. --------------------------------------------------------------------------------
Predictions of soil surface and topsoil organic carbon content through the use of laboratory and field spectroscopy in the Albany Thicket Biome of Eastern Cape Province of South Africa
Nocita, M. ; Kooistra, L. ; Bachmann, M. ; Müller, A. ; Powell, M. ; Weel, S. - \ 2011
Geoderma 167-168 (2011). - ISSN 0016-7061 - p. 295 - 302.
infrared reflectance spectroscopy - least-squares regression - in-situ characterization - agricultural soils - river floodplains - nir spectroscopy - meta analysis - sequestration - spectrometry - nitrogen
In recent years it has been shown that laboratory and field visible near infrared spectroscopy (VNIRS) allows for the accurate prediction of soil organic carbon (SOC) — more rapidly, less expensively, and at larger scales than conventional soil laboratory methods. VNIRS might find application in the restoration assessment of the degraded, semi-arid subtropical thickets of the Albany Thicket Biome (ATB) of the Eastern Cape Province of South Africa. During the twentieth century, the semi-arid forms of the ATB suffered heavy browsing by goats, transforming the dense closed-canopy shrubland into an open savannah-like system. This paper presents a study dealing with SOC estimation of soil surface (0–5 mm) and topsoil (0–200 mm) in the degraded ATB, through the combination of soil spectroscopy and partial least square regression (PLSR). Spectroscopic measurements and soil samples were collected along a transect in the ATB. The PLSR models developed with laboratory and field spectra gave good predictions of SOC, with root mean square error of validation (RMSEV) <5.0 and 5.5 g C kg- 1, respectively. The use of the full visible near-infrared spectral range gave better SOC predictions than using either visible or near-infrared separately. The resampling simulation of the field surface spectra to the 232 channels of the satellite-born EnMAP sensor gave good SOC predictions for laboratory conditions (RPD > 2), but low accuracy (RMSE: 9.88 g C kg- 1) for field model. The results of this research study indicated that, for the ATB, (i) combining soil spectroscopy and PLSR does favor accurate prediction of SOC, (ii) the predictions of surface SOC can be used as a proxy of topsoil SOC, and (iii) there is potential for future application of satellite-born hyperspectral data for SOC content predictions. --------------------------------------------------------------------------------
Cadmium Accumulation in Small Mammals: Species Traits, Soil Properties, and Spatial Habitat Use
Brink, N.W. van den; Lammertsma, D.R. ; Dimmers, W.J. ; Boerwinkel, M.C. - \ 2011
Environmental Science and Technology 45 (2011)17. - ISSN 0013-936X - p. 7497 - 7502.
mice apodemus-sylvaticus - heavy-metal concentrations - river floodplains - food-web - earthworms - lead - diet - bioaccumulation - stressors - pollution
In this study, the impact of species-specific spatial habitat use, diet preferences, and soil concentrations and properties on the accumulation of cadmium in small mammals was investigated. The results show that for the wood mouse (Apodemus sylvaticus), a mobile species with a large range in diet composition, accumulation of cadmium was not related to local soil concentrations or soil properties, but to diet preferences. For the common vole (Microtus arvalis), a nonmobile, specific feeding species, accumulation of cadmium was related to local soil concentrations or properties. For the bank vole (Myodes glareolus), a species with a smaller home range than the wood mouse but a broader diet spectrum than the common vole, both local soil properties and diet appeared to affect the cadmium accumulation in the kidneys. The results of this field study show that species-specific traits of small mammals are important determinants of accumulation of cadmium on a local scale. For site-specific assessment of risks of contaminants, such information is essential in order to understand exposure dynamics
Are laboratory derived toxicity results informative for field situations? Case study on earthworm populations contaminated with heavy metals
Klok, T.C. ; Thissen, J. - \ 2009
Soil Biology and Biochemistry 41 (2009)2. - ISSN 0038-0717 - p. 251 - 255.
eisenia-foetida oligochaeta - godwit limosa-limosa - lumbricus-rubellus - river floodplains - growth - reproduction - soil - consequences - temperature - netherlands
The relevance of laboratory tests on toxicants for field situations is often disputed given that laboratory tests are conducted under, next to the toxicant stress, optimal conditions which are not expected in field situations. In this paper we confront the results of laboratory tests on growth, reproduction and survival of earthworms, in a polluted and a reference field soil with a field inventory of earthworms. The field inventory includes population density, biomass and demographic composition in life stages measured monthly over a period of one year. The field inventory showed that density and biomass was higher at the polluted field site, a result in conflict with the extrapolation of the laboratory tests that showed a decrease in population growth rate by 23% at this site compared to the reference. The field inventory and laboratory derived results agreed in the demographic composition of the population with more individuals in the younger age class at the polluted site compared to the reference. Abiotic and biotic conditions that differ between sites and could possibly explain the lower earthworm biomass and density at the reference site are discussed. We suggest that predation by the two to five times higher densities of meadow birds in spring may have caused the lower density and biomass of earthworms at the reference site.
Toxicological risks for small mammals in a diffusely and moderately polluted floodplain
Wijnhoven, S. ; Leuven, R.S.E.W. ; Velde, G. van der; Eijsackers, H.J.P. - \ 2008
Science of the Total Environment 406 (2008)3. - ISSN 0048-9697 - p. 401 - 406.
metal accumulation - river floodplains - heavy-metals - food-chain - cadmium - exposure - liver - lead - mice - bioaccumulation
The ecotoxicological risk of heavy metal pollution in diffusely polluted floodplains is largely unclear, as field-based data are scarce. This study investigated cadmium (Cd) and lead (Pb) accumulation in the liver and kidneys of small mammal species (voles, mice and shrews) from a moderately polluted Dutch floodplain. The Cd and Pb concentrations were compared with effect concentrations (ECs). Reported ECs in literature varied considerably, with the lowest values frequently exceeded by our values, whereas the highest values were encountered only occasionally. Cd and Pb levels were highest in the shrew species, particularly in Sorex araneus. Although toxicological effects at the specimen level were present in these floodplains, effects at population level are thought to be limited, as a result of the animals' relatively short life expectancies (due to recurrent floods) and the rapid maturation of small mammals. Exceptionally high tissue metal concentrations in some specimens of all species indicated local hotspots with peaks in metal concentrations. Sanitizing such local hotspots might reduce toxicological risks. (C) 2008 Published by Elsevier B.V.
Flooding responses of three earthworm species, Allolobophora chlorotica, Aporrectodea caliginosa and Lumbricus rubellus, in a laboratory-controlled environment
Zorn, M.I. ; Gestel, C.A.M. van; Morriën, W.E. ; Wagenaar, M. ; Eijsackers, H.J.P. - \ 2008
Soil Biology and Biochemistry 40 (2008)3. - ISSN 0038-0717 - p. 587 - 593.
river floodplains - soil - contamination - populations - grassland - dynamics
To get a better understanding of earthworm' responses towards flooding, three laboratory experiments were performed with the species Allolobophora chlorotica, Aporrectodea caliginosa and Lumbricus rubellus. Flooding response was determined in a pot experiment, in which the earthworms were incubated for 42 days in flooded or non-flooded soil, with or without heavy metal pollution. To determine moisture preference, earthworms were incubated for 9 days in aquaria with five compartments, containing soil with a moisture gradient (%, w/w), ranging from 35%, 45% (field capacity), 55%, 65% (saturated) to 65% + (saturated and an extra water layer). Effects on earthworm health were studied by incubating earthworms of each species for 42 days in soil with the same range of moisture contents and determining the dry/wet weight ratio and dry weight gain as an indication of earthworm health. A. chlorotica was tolerant to water, although the worms tended to escape from flooded soil. Their health was significantly lower in the flooded soils (P
Heavy-metal concentrations in small mammals from a diffusely polluted floodplain: Importance of species- and location-specific characteristics
Wijnhoven, S. ; Leuven, R.S.E.W. ; Velde, G. van der; Jungheim, G. ; Koelemij, E.I. ; Vries, F.T. de; Eijsackers, H.J.P. ; Smits, A.J.M. - \ 2007
Archives of Environmental Contamination and Toxicology 52 (2007)4. - ISSN 0090-4341 - p. 603 - 613.
ecological risk-assessment - river floodplains - food-chain - spatial variability - apodemus-sylvaticus - cadmium - accumulation - netherlands - grassland - shrews
The soil of several floodplain areas along large European rivers shows increased levels of heavy metals as a relict from past sedimentation of contaminants. These levels may pose risks of accumulation in food webs and toxicologic effects on flora and fauna. However, for floodplains, data on heavy-metal concentrations in vertebrates are scarce. Moreover, these environments are characterised by periodical flooding cycles influencing ecologic processes and patterns. To investigate whether the suggested differences in accumulation risks for insectivores and carnivores, omnivores, and herbivores are reflected in the actual heavy-metal concentrations in the species, we measured the current levels of Zn, Cu, Pb, and Cd in 199 specimens of 7 small mammal species (voles, mice, and shrews) and in their habitats in a diffusely polluted floodplain. The highest metal concentrations were found in the insectivorous and carnivorous shrew, Sorex araneus. Significant differences between the other shrew species, Crocidura russula, and the vole and mouse species was only found for Cd. The Cu concentration in Clethrionomys glareolus, however, was significantly higher than in several other vole and mouse species. To explain the metal concentrations found in the specimens, we related them to environmental variables at the trapping locations and to certain characteristics of the mammals. Variables taken into account were soil total and CaCl2-extractable metal concentrations at the trapping locations; whether locations were flooded or nonflooded; the trapping season; and the life stage; sex; and fresh weight of the specimens. Correlations between body and soil concentrations and location or specimen characteristics were weak. Therefore; we assumed that exposure of small mammals to heavy-metal contamination in floodplains is significantly influenced by exposure time, which is age related, as well as by dispersal and changes in foraging and feeding patterns under influence of periodic flooding.
Photosynthetic consequences of phenotypic plasticity in response to submergence: Rumex palustris as a case study
Mommer, L. ; Pons, T.L. ; Visser, E.J.W. - \ 2006
Journal of Experimental Botany 57 (2006)2. - ISSN 0022-0957 - p. 283 - 290.
radial oxygen loss - aquatic plant-communities - deep-water rice - terrestrial plant - amphibious plants - underwater photosynthesis - river floodplains - light acclimation - inorganic carbon - gas-exchange
Survival and growth of terrestrial plants is negatively affected by complete submergence. This is mainly the result of hampered gas exchange between plants and their environment, since gas diffusion is severely reduced in water compared with air, resulting in O2 deficits which limit aerobic respiration. The continuation of photosynthesis could probably alleviate submergence-stress in terrestrial plants, but its potential under water will be limited as the availability of CO2 is hampered. Several submerged terrestrial plant species, however, express plastic responses of the shoot which may reduce gas diffusion resistance and enhance benefits from underwater photosynthesis. In particular, the plasticity of the flooding-tolerant terrestrial species Rumex palustris turned out to be remarkable, making it a model species suitable for the study of these responses. During submergence, the morphology and anatomy of newly developed leaves changed: ‘aquatic’ leaves were thinner and had thinner cuticles. As a consequence, internal O2 concentrations and underwater CO2 assimilation rates were higher at the prevailing low CO2 concentrations in water. Compared with heterophyllous amphibious plant species, underwater photosynthesis rates of terrestrial plants may be very limited, but the effects of underwater photosynthesis on underwater survival are impressive. A combination of recently published data allowed quantification of the magnitude of the acclimation response in this species. Gas diffusion resistance in terrestrial leaves underwater was about 15¿000 times higher than in air. Strikingly, acclimation to submergence reduced this factor to 400, indicating that acclimated leaves of R. palustris had an approximately 40 times lower gas diffusion resistance than non-acclimated ones.
Ecophysiological determinants of plant performance under flooding: a comparative study among seven plant families
Mommer, L. ; Lenssen, J.P.M. ; Huber, H. ; Visser, E.J.W. ; Kroon, H. de - \ 2006
Journal of Ecology 94 (2006)6. - ISSN 0022-0477 - p. 1117 - 1129.
shoot elongation - underwater photosynthesis - complete submergence - river floodplains - terrestrial plant - amphibious plants - oxygen diffusion - rumex-palustris - path-analysis - growth-rate
1 Plant performance of species in river floodplains is negatively affected by submergence, due to severely hampered gas exchange under water. Several individual traits have been shown to determine flooding tolerance, but the interrelationships among these traits and their effects on plant performance still remain largely unknown. 2 Here, we aim for a more coherent understanding of submergence tolerance, by investigating whether different traits are alternative strategies to enhance survival under water or whether these traits act in concert. 3 Because responses to submergence may be taxon-specific, we chose a multiple-species approach that allowed phylogenetic comparisons. The phenotypic traits investigated in the current study were constitutively different in species originating from frequently flooded habitats than in species from dry habitats: wet species were taller and had a higher specific leaf area (SLA), chlorophyll content, aerenchyma content, and longer longevity of terrestrial and ‘aquatic’ leaves compared with species from dry habitats. Moreover, the frequently flooded species appeared to be more plastic for these traits in response to submergence. Neither the phylogenetic component nor the light climate under water were important for the expression of the submergence-related traits. 4 Principal component analysis (PCA) showed that these traits were divided in two independent clusters structured either around the petiole (i.e. aerenchyma content and shoot length) or the leaf lamina (i.e. SLA, chlorophyll content and leaf longevity). Shoot length and aerenchyma content of the petiole were also positively correlated, albeit not significantly. A positive correlation between SLA and leaf longevity was observed under water, indicating that thinner leaves may have an increased potential for gas exchange, resulting in increased leaf longevity and plant survival. 5 Path analyses indicated significant positive effects of the two trait clusters on plant performance during full submergence. 6 Our study shows that multiple ecophysiological traits act in concert to fine tune responses to dynamic and unpredictable environments such as river floodplains.
Water-level fluctuations affect macrophyte richness in floodplain lakes
Geest, G.J. van; Wolters, H. ; Roozen, F.C.J.M. ; Coops, H. ; Roijackers, R.M.M. ; Buijse, A.D. ; Scheffer, M. - \ 2005
Hydrobiologia 539 (2005)1. - ISSN 0018-8158 - p. 239 - 248.
waterplanten - stroomvlakten - vegetatie - meren - rivieren - biodiversiteit - plantensuccessie - nederland - waterstand - aquatische ecosystemen - rijn - aquatic plants - floodplains - vegetation - lakes - rivers - biodiversity - plant succession - netherlands - water level - aquatic ecosystems - river rhine - shallow eutrophic lakes - aquatic plant diversity - long-term - river floodplains - seed dispersal - germination - connectivity - channels - dynamics
The characteristic ecology of floodplain lakes is in part due to their relatively strong water-level fluctuations. We analyzed the factors determining water-level fluctuations in 100 floodplain lakes (during non-flooded conditions) in the active floodplains of the Lower Rhine in the Netherlands. Furthermore, we explored the relationship between water-level fluctuations and macrophyte species richness, and analyzed the suitability of artificially created lakes for macrophyte vegetation. During non-flooded conditions along the Rhine, lake water-level fluctuations are largely driven by groundwater connection to the river. Hence, water-level fluctuations are largest in lakes close to the main channel in strongly fluctuating sectors of the river and smallest in isolated lakes. Additionally, water-level fluctuations are usually small in old lakes, mainly due to reduced groundwater hydraulic conductivity resulting from accumulated clay and silt on the bottom. Species richness of floating-leaved and emergent macrophytes was reduced at both small and large water-level fluctuations, whereas species richness of submerged macrophytes was reduced at small water-level fluctuations only. In addition, species richness of submerged macrophytes was higher in lakes that experienced drawdown, whereas no similar pattern was detected for floating-leaved and emergent macrophytes. The decline in amplitude of lake water-level with lake age implies that the number of hydrologically dynamic lakes will decrease over time. Therefore, we suggest that excavation of new lakes is essential to conserve the successional sequence of floodplain water bodies including conditions of high biodiversity. Shallow, moderately isolated, lakes with occasional bottom exposure have the highest potential for creating macrophyte-rich floodplain lakes along large lowland rivers. The water-level regime of such lakes can in part be designed, through choice of the location along the river, the distance away from the river and the depth profile of the lake.
A comparison of methods to relate grass reflectance to soil metal contamination
Kooistra, L. ; Leuven, R.S.E.W. ; Wehrens, H.R.M.J. ; Nienhuis, P.H. ; Buydens, L.M.C. - \ 2003
International Journal of Remote Sensing 24 (2003)24. - ISSN 0143-1161 - p. 4995 - 5010.
river floodplains - leaf - selection - index - field - band
Grass-dominated vegetation covers large areas of the Dutch river floodplains. Remotely sensed data on the conditions under which this vegetation grows may yield information about the degree of soil contamination. This paper explores the relationship between grassland canopy reflectance and zinc (Zn) contamination in the soil under semi-field conditions. A field radiometer was used to record reflectance spectra of perennial ryegrass (Lolium perenne) in an experimental field with Zn concentrations in the soil ranging from 32 to 1800 mg kg-1. Several spectral vegetation indices (VIs) and a multivariate approach using partial least squares (PLS) regression were investigated to evaluate their potential use in estimating Zn contamination levels. Compared to the best PLS model (RMSEP=181.4 mg kg-1), the narrow band vegetation index MSAVI2mm performed better (RMSEP=162.9 mg kg-1). Both MSAVI2mm and PLS gave a high user accuracy for the strongly contaminated soil class (100% and 91%, respectively), while the total accuracy was satisfactory (60% and 55%, respectively). Results from this feasibility study indicate the potential of using remote sensing techniques for the classification of contaminated areas in river floodplains. But as the results from this study may be both resolution- and location-dependent, research on field and image scale is now required to test the established relations and to assess their susceptibility to seasonal influences, species heterogeneity, and increased levels of spectral noise.