Flood forests of the inner Niger delta, mali; past, present, and future
Beintema, A.J. ; Fofana, B. ; Faye, A. ; Huiskes, H.P.J. - \ 2005
Wageningen : Alterra (Alterra-rapport 1316) - 52
laagland bossen - stroomvlakten - bossen - west-afrika - vogels - biodiversiteit - delta's - rivieren - bottomland forests - floodplains - forests - west africa - birds - biodiversity - deltas - rivers
Flood forests have a special place in the Inner Niger Delta, Mali. They have a great economic value for the local populations, and are hotspots of biodiversity in the delta. This report reviews the status of all flood forests in the Inner Niger Delta, Mali, that are presently known, or have been known to exist in the past. In total, the status of 39 sites has been evaluated. Of the remaining 37 sites, 8 have been totally lost and cleared, while 22 have been severely degraded, losing their function for colonial waterbirds. This leaves 7 forests in a more or less healthy state some of which host very large mixed colonies of waterbirds. Of the severely degraded forests, 8 are included in restoration projects by Wetlands International and IUCN. Of these 8, two still hold small numbers of breeding birds, which means that are forests which have breeding birds and can be considered future nuclei if they are further developed. Based on this, and on a judgement on the other forests, a strategic plan has been developed for the restoration of a functional network of flood forests in the delta.
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.
Temporal variation of trace metal geochemistry in floodplain lake sediment subject to dynamic hydrological conditions
Griethuysen, C. van; Luitwieler, M. ; Joziasse, J. ; Koelmans, A.A. - \ 2005
Environmental Pollution 137 (2005)2. - ISSN 0269-7491 - p. 281 - 294.
zware metalen - geochemie - meren - oppervlaktewater - waterverontreiniging - stroomvlakten - hydrologie - nederland - gelderland - land van maas en waal - heavy metals - geochemistry - lakes - surface water - water pollution - floodplains - hydrology - netherlands - gelderland - land van maas en waal - acid-volatile sulfide - fresh-water sediments - elements - estuary - solids - avs
Climate change and land use may significantly influence metal cycling in dynamic river systems. We studied temporal variation of sediment characteristics in a floodplain lake, including concentrations of dissolved organic carbon, acid volatile sulfide and trace metals. The sampling period included a severe winter inundation and a dramatic water level drop during summer. Temporal changes were interpreted using multivariate analysis and chemical equilibrium calculations. Metal concentrations in sediment increased with depth, indicating a gradual improvement of sediment quality. In contrast, dissolved metal concentrations were highest in top layers due to mobilization from oxyhydroxides and precipitation with sulfides in deeper layers. Inundation had a mobilizing effect as it stimulated resuspension and oxygenation of sediment top layers. Water table lowering combined with organic matter decomposition led to immobilization due to sulfide formation. The chemistry of the sediments was consistent with model calculations, especially for macro-elements. The results illustrate the importance of seasonality for metal risk assessment.
Succession of aquatic vegetation driven by reduced water-level fluctuations in floodplain lakes
Geest, G.J. van; Coops, H. ; Roijackers, R.M.M. ; Buijse, A.D. ; Scheffer, M. - \ 2005
Journal of Applied Ecology 42 (2005)2. - ISSN 0021-8901 - p. 251 - 260.
meren - plantensuccessie - stroomvlakten - vegetatie - nederland - waterstand - aquatische ecosystemen - rijn - lakes - plant succession - floodplains - vegetation - netherlands - water level - aquatic ecosystems - river rhine - river-margin vegetation - rhone river - plant diversity - flow regulation - boreal rivers - connectivity - channels - macrophytes - disturbance - sediment
In recent years, interest has grown in restoring floodplain function of regulated rivers. Successful rehabilitation of riparian systems requires knowledge of how regulation of river flow affects biodiversity and ecosystem function. The effects of changes in the river's low water-level regime on aquatic ecosystems in floodplains has received little attention so far. The aquatic vegetation of 215 floodplain lakes along the Lower Rhine (the Netherlands) was analysed in relation to lake characteristics and lake water-level fluctuations in 1999–2000. Vegetation composition was related to lake morphology and age, cattle access to the shoreline, the amount of time the river was in flood, and lake sediment area exposed at low water level (drawdown). Surprisingly, vegetation composition was correlated more strongly with lake age and occurrence of drawdown than the amount of time the river was in flood
1. In recent years, interest has grown in restoring floodplain function of regulated rivers. Successful rehabilitation of riparian systems requires knowledge of how regulation of river flow affects biodiversity and ecosystem function. The effects of changes in the river's low water-level regime on aquatic ecosystems in floodplains has received little attention so far. 2. The aquatic vegetation of 215 floodplain lakes along the Lower Rhine (the Netherlands) was analysed in relation to lake characteristics and lake water-level fluctuations in 1999-2000. 3. Vegetation composition was related to lake morphology and age, cattle access to the shoreline, the amount of time the river was in flood, and lake sediment area exposed at low water level (drawdown). Surprisingly, vegetation composition was correlated more strongly with lake age and occurrence of drawdown than the amount of time the river was in flood. 4. In older lakes, water-level fluctuations are reduced due to an accumulation of clay and silt that 'seals' sediment, preventing drawdown during periods of low river levels. Our results suggest that this clay sealing process is a major driving force for aquatic vegetation succession in floodplain lakes along the Lower Rhine, as succession drives from desiccation-tolerant species (e.g. Chara spp.) in young lakes to desiccation-sensitive species (e.g. Nuphar lutea) in old lakes. 5. Water levels were stable in lakes along a river branch that was impounded below mean flow only. Here, the original low water-level regime has been replaced by an artificial regime with higher water levels than would be expected naturally. Consequently, in these lakes drawdown was rare or absent, and the aquatic macrophyte vegetation was characterized by low species richness and frequent dominance by the invasive species Elodea nuttallii. 6. Synthesis and applications. Our results show that stabilization of river water levels during low flow may negatively affect vegetation composition and succession in floodplain lakes adjacent to these rivers. A management scheme including incidental temporary lowering of the river water level, which results in drawdown of floodplain lakes, would enhance the ecological status of those rivers with stabilized water levels during low flow.
Analyzing the causes for the persistence of chironomids in flood plain lake sediments
Haas, E.M. de; Haaren, R. van; Koelmans, A.A. ; Kraak, M.H.S. ; Admiraal, W. - \ 2005
Archiv für Hydrobiologie 162 (2005)2. - ISSN 0003-9136 - p. 211 - 228.
sediment - verontreinigende stoffen - chironomus riparius - benthos - waterverontreiniging - stroomvlakten - zware metalen - meren - biotesten - nederland - ecotoxicologie - waterbodems - rijn - waal - sediment - pollutants - chironomus riparius - benthos - water pollution - floodplains - heavy metals - lakes - bioassays - netherlands - ecotoxicology - water bottoms - river rhine - river waal - quality triad approach - benthic invertebrates - community composition - marine sediment - riparius larvae - toxicity - diptera - river - deformation
The aim of the present study was to analyse the causes for the absence and persistence of chironomids in sediments with a complex pollution history. Observations on the benthic community composition in floodplain lake sediments of the River Rhine, differing in contaminant level and food quality, were combined with laboratory and in situ bioassays, using the midge Chironomus riparius as a model species. The positive relation between food quality and the diversity of the communities indicated that food quality is an important factor regulating benthic community composition, overriding the potential effects of contaminants. Nevertheless, in sediments with high contaminant levels, high densities of species classified as 'pollution-tolerant', such as Chironomus sp., were observed. The laboratory bioassays verified that the contaminant concentrations in these sediments had no direct effect on survival and growth of C. riparius, although higher contaminant concentrations in the sediment resulted in a higher incidence of mentum deformities. Also, the high growth rate of C. riparius in the in situ enclosures in two of the most contaminated sediments indicated chemical stress and mentum deformities did not exclude rapid growth. This observation agrees with the abundance of the resident pollution-tolerant chironomids of the Chironomus plumosus group. In addition, the in situ bioassay pointed out that predation on chironomids added to the field enclosures was significant and is also an important factor in regulating the abundance of chironomids. In sediments with the highest food quality and low levels of contaminants the opportunistic chironomids may have been outcompeted by benthic invertebrate taxa that are not able to persist at more contaminated sites. It is concluded that tolerance of opportunistic chironomids, such as Chironomus sp., combined with their rapid rate of development, enables them to persist in contaminated sediments that are organically enriched avoiding competition with other invertebrates
Edelherten in de Gelderse Poort : haalbaarheidsstudie
Groot Bruinderink, G.W.T.A. ; Lammertsma, D.R. ; Kuiters, A.T. ; Griffioen, A.J. ; Kuipers, H. - \ 2005
Wageningen : Alterra (Alterra-rapport 1153) - 96
wildbeheer - cervus elaphus - edelherten - stroomvlakten - introductie - vegetatie - nederland - monitoring - ecologische hoofdstructuur - gelderland - gelderse poort - wildlife management - cervus elaphus - red deer - floodplains - introduction - vegetation - netherlands - monitoring - ecological network - gelderland - gelderse poort
De Gelderse Poort is een grote eenheid natuur die in potentie een belangrijk onderdeel vormt van een robuuste ecologische verbindingszone voor edelherten tussen de Veluwe en het Maaswoud. Dit rapport presenteert een werkplan voor een proef met edelherten in dit gebied. Belangrijke aspecten van deze proef zijn: het terreingebruik, de gevolgen van hoogwater en de effecten op de vegetatie. In dit laatste zit besloten de relatie met de veiligheid van de rivier, in de zin van het vermogen tot waterafvoer. Ook de gezondheid en het welzijn van de dieren worden gemonitord. Voorgesteld wordt om de proef op twee locaties uit te voeren: de Groenlanden/Bisonbaai en de Millingerwaard. De resultaten van de proef zijn van belang bij de afweging of de ecologische verbindingszone kan worden gerealiseerd. Daarom moeten zij in dat perspectief kunnen worden geïnterpreteerd. Om die reden wordt in afzonderlijke hoofdstukken ingegaan op, in volgorde: de leefwijze van het edelhert, de gewenste startpopulatie, aspecten van gezondheid en welzijn en de verwachtingen omtrent menukeus en terreingebruik. Het slothoofdstuk gaat in op een groot aantal aspecten die samenhangen met het perspectief van een vrijlevende populatie edelherten.
Groene rivier biedt perspectief : nieuw leven in discussie over waterberging
Wolfert, H.P. - \ 2004
Boomblad 16 (2004)2. - ISSN 0924-0101 - p. 4 - 5.
waterbeheer - wateropslag - rivieren - stroomvlakten - ruimtelijke ordening - landgebruik - gelderland - uiterwaarden - physical planning - land use - water management - water storage - rivers - floodplains - gelderland - river forelands
Alterra-onderzoeker ontwierp voor het knooppunt Arnhem-Nijmegen (KAN-gebied) een nieuwe, groene rivier die in de toekomstige behoefte aan waterberging voorziet. Dit plan dat samen met WL Delft Hydraulics is opgesteld, heeft ook mogelijkheden in zich voor luxe woningen, natuur, recreatie en extensieve landbouw
Klimaatsverandering en functionele plantengroepen in wetlands; uitwerking functionele plantengroepen voor rivierdynamiek
Nijhof, B.S.J. ; Wamelink, G.W.W. ; Runhaar, J. - \ 2004
Wageningen : Alterra (Alterra-rapport 1121) - 84
vegetatie - wetlands - stroomvlakten - klimaatverandering - vegetatietypen - soorten - vegetation - wetlands - floodplains - climatic change - vegetation types - species
Bij het voorspellen van effecten van ingrepen op vegetaties wordt vaak uitgegaan van indicatiesystemen gebasseerd op standplaatscondities. Een andere benadering is het voorspellen van voorkomen van soorten op basis van functionele eigenschappen. In populatie-ecologisch onderzoek gericht op successie wordt dit veel toegepast, e.g. de C-S-R-benadering van Grime. Is een dergelijke benadering een vervanging van of een aanvulling op de bestaande indicatiesystemen? Kan de functionele benadering het hiaat in de voorspelling van het effect van dynamische processen in rivieren, welke met de bestaande indiactiesystemen niet of onvoldoende voorspeld kan worden, opvullen? Wat is de voorspellende waarde van de functionele benadering? In literatuuronderzoek en door middel van een experiment wordt getracht deze vragen te beantwoorden.
Sediment pollution and predation affect structure and production of benthic macroinvertebrate communities in the Rhine-Meuse delta, The Netherlands
Lange, H.J. de; Jonge, J. de; Besten, P.J. den; Oosterbaan, J. ; Peeters, E.T.H.M. - \ 2004
Journal of the North American Benthological Society 23 (2004)3. - ISSN 0887-3593 - p. 557 - 579.
waterverontreiniging - waterinvertebraten - zware metalen - sediment - besmetters - stroomvlakten - predatie - toxicologie - nederland - ecotoxicologie - rijn - maas - zuid-holland - water pollution - aquatic invertebrates - heavy metals - sediment - contaminants - floodplains - predation - toxicology - netherlands - ecotoxicology - river rhine - river meuse - zuid-holland - saint-francois quebec - acid volatile sulfide - invertebrate community - toxicological factors - population-dynamics - floodplain lakes - fresh-water - availability - bioavailability - extraction
Most floodplain sediments of the rivers Rhine and Meuse in The Netherlands are moderately polluted with trace metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and other chemicals. The effects of these sediment-bound contaminants on the productivity of benthic macroinvertebrates are unclear. Sixteen locations along a pollution gradient were investigated in creeks in the Biesbosch floodplain area. Sediment samples were analyzed for bulk sediment characteristics and contaminants (total and bioavailable concentrations of trace metals, PAHs, and PCBs). Exclosures were used to study the effect of predation by fish and birds on macroinvertebrates. Macroinvertebrates were sampled and identified to species level, and production was estimated from biomass increases inside the exclosures during a 1-mo interval in spring
Most floodplain sediments of the rivers Rhine and Meuse in The Netherlands are moderately polluted with trace metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and other chemicals. The effects of these sediment-bound contaminants on the productivity of benthic macroinvertebrates are unclear. Sixteen locations along a pollution gradient were investigated in creeks in the Biesbosch floodplain area. Sediment samples were analyzed for bulk sediment characteristics and contaminants (total and bioavailable concentrations of trace metals, PAHs, and PCBs). Exclosures were used to study the effect of predation by fish and birds on macroinvertebrates. Macroinvertebrates were sampled and identified to species level, and production was estimated from biomass increases inside the exclosures during a 1-mo interval in spring. Benthic macroinvertebrate species richness was negatively affected by sediment contamination. Production of oligochaetes and chironomids was not correlated with levels of contamination, but production of gastropods was negatively correlated with contamination. Environmental variables that reflected food availability (seston and sediment organic C) were positively correlated with contamination. Predation significantly reduced invertebrate biomass, but the effects of predation and sediment contamination were not correlated with each other. Our study suggested that the moderate levels of contamination affected the structure but not the productivity of the benthic macroinvertebrate community, probably because of the counteracting effects of contamination and associated surplus of food.
Integration of ecological aspects in flood protection strategies: defining an ecological minimum
Geilen, N. ; Jochems, H. ; Krebs, L. ; Muller, S. ; Pedroli, G.B.M. ; Sluis, T. van der; Looy, K. van; Rooij, S.A.M. van - \ 2004
River Research and Applications 20 (2004)3. - ISSN 1535-1459 - p. 269 - 283.
hoogwaterbeheersing - stroomvlakten - herstel - ecologie - ruimtelijke ordening - alluviaal land - vegetatie - carabidae - coleoptera - maas - flood control - floodplains - rehabilitation - ecology - physical planning - alluvial land - vegetation - carabidae - coleoptera - river meuse - river health - habitat - biodiversity
Policy makers are confronted with the question of how to combine sustainable flood protection and floodplain rehabilitation in the best possible way. Both topics deal with spatial planning aspects in a range of scales. This question was the starting point for the development of an evaluation method within the IRMA/SPONGE project INTERMEUSE, illustrated on the basis of assumed flood protection strategies in the Meuse river basin (the sponge strategy, the retention strategy, and the floodplain lowering or winter bed strategy). The integration of flood protection and floodplain rehabilitation can be performed on two scale levels that are interrelated: on the regional level the focus is on (large parts of) an entire stream basin; on the local level specific site conditions are taken as starting point. Ecological aspects under study are spatial cohesion of habitats as identified by species population persistence modelling (regional, longitudinal level) and required habitat quality for carabid beetles and for meadow vegetation gradients as assessed by correspondence analysis (local, transversal level). The carabid beetles are taken as indicative for the ecological integrity of the river bed, the meadow vegetation for that of the floodplain. A unifying concept in the evaluation of ecological integrity is the ecological minimum: the critical boundary or minimum level of habitat conditions for a potentially good ecological functioning. It is the least acceptable state for a river ecosystem that is still functional to some extent, compared to a natural river ecosystem. The results of this study show clearly that there is a good chance to combine floodplain rehabilitation aims with flood protection activities, both on a local and on an international scale. Although ecological effect assessment and ecological optimizing (referring to a natural reference state) remain basic, additionally the assessment of the ecological minimum helps to define design strategies for integrated flood protection, especially in situations where there is an opportunity for river rehabilitation.
Trace metal availability and effects on benthic community structure in floodplain lakes
Griethuysen, C. van; Baren, J. van; Peeters, E.T.H.M. ; Koelmans, A.A. - \ 2004
Environmental Toxicology and Chemistry 23 (2004)3. - ISSN 0730-7268 - p. 668 - 681.
meren - stroomvlakten - sporenelementen - waterorganismen - waterverontreiniging - rijn - waal - ijssel - aquatic organisms - water pollution - lakes - floodplains - trace elements - river rhine - river waal - river ijssel - acid-volatile sulfide - simultaneously extracted metals - macroinvertebrate community - contaminated sediments - cadmium accumulation - in-situ - invertebrates - toxicity - avs - bioavailability
Effects of contaminants on communities are difficult to assess and poorly understood. We analyzed in situ effects of trace metals and common environmental variables on benthic macroinvertebrate communities in floodplain lakes. Alternative measures of trace metal availability were evaluated, including total metals, metals normalized on organic carbon (OC) or clay, simultaneously extracted metals (SEM), combinations of SEM and acid-volatile sulfide (AVS), and metals accumulated by detritivore invertebrates (Oligochaeta). Accumulated metal concentrations correlated positively with sediment trace metals and negatively with surface water dissolved OC. Sixty-eight percent of the variation in benthic community composition was explained by a combination of 11 environmental variables, including sediment, water, and morphological characteristics with trace metals. Metals explained 2 to 6% of the community composition when SEM — AVS or individual SEM concentrations were regarded. In contrast, total, normalized, and accumulated metals were not significantly linked to community composition. We conclude that examination of SEM or SEM — AVS concentrations is useful for risk assessment of trace metals on the community level.
Immigration: a potential time bomb under the integration of Conservation and Development
Scholte, P. - \ 2003
Ambio 32 (2003)1. - ISSN 0044-7447 - p. 58 - 64.
natuurbescherming - stroomvlakten - herstel - wildbescherming - kameroen - projecten - internationale samenwerking - nederland - nature conservation - wildlife conservation - floodplains - rehabilitation - projects - international cooperation - netherlands - cameroon - africa - biodiversity - management - parks
Integrated Conservation and Development Projects (ICDPs) aim to stimulate conservation without the previous negative experiences for local people, but pay little attention to their long-term impact such as immigration. The rehabilitation of the Logone floodplain in North Cameroon, the core activity of the Waza-Logone ICDP, has led to a 34% increase of sedentary fishermen and a multiple number of temporary fishermen. Whereas livestock pressure tripled, kob antelopes, a key floodplain species, have not increased, reducing their competitiveness. The virtual disappearance of wildlife in nearby Kalamaloue National Park (NP), due to advanced human encroachment forms, is therefore a bleak perspective for Waza NP. Examples from the Central African Republic (CAR), Galapagos, Nigeria and Zimbabwe also showed that in open-access systems, improvement in living standards (development) may stimulate immigration, jeopardizing the stability necessary in protected areas (conservation). Most ICDPs lack demographic monitoring, masking its possible immigration risk. To counter the immigration risk in Waza, a policy was formulated based on local stakeholder categorization and subsequent privileges, resulting in the voluntarily displacement of a village out of Waza NP. It is further recommended that ICDPs should be involved in regional land-use planning and discourage development activities that stimulate immigration.
|Sedimentation on embanked floodplains of the rivers Waal and IJssel
Maas, G.J. ; Makaske, B. - \ 2003
In: Proceedings NCR-days 2002; current themes in Dutch river research / Leuven, R.S.E.W., van Os, A.G., Nienhuis, P.H., Delft : NCR - p. 122 - 124.
geologische sedimentatie - rivieren - stroomvlakten - waal - ijssel - geological sedimentation - rivers - floodplains - river waal - river ijssel
The potential of field spectroscopy for the determination of sediment properties in river floodplains
Kooistra, L. ; Wanders, J. ; Epema, G.F. ; Leuven, R.S.E.W. ; Wehrens, H.R.M.J. ; Buydens, L.M.C. - \ 2003
Analytica Chimica Acta 484 (2003)2. - ISSN 0003-2670 - p. 189 - 200.
bodemeigenschappen - geologische sedimentatie - stroomvlakten - rivieren - spectroscopie - klei - organische stof - nederland - bodemkwaliteit - rijn - soil properties - geological sedimentation - floodplains - rivers - spectroscopy - clay - organic matter - netherlands - soil quality - river rhine - diffuse-reflectance spectroscopy - near-infrared spectroscopy - organic-matter - contamination - calibration - networks
Investigations have shown that visible-near-infrared (VNIR) spectroscopy can accurately determine soil properties under laboratory conditions. In situ assessment of soil properties is of great benefit for several applications, as spectra can be acquired fast and almost continuously. The present study used partial least squares (PLS) regression to establish a relationship between soil reflectance spectra measured under field conditions and the organic matter and clay content of the soil. Spectra were acquired with a fieldspectrometer in a recently reconstructed floodplain along the river Rhine in The Netherlands. Several spectral pre-processing methods were employed to improve the performance and robustness of the models. Results indicate that, under varying surface conditions, field spectroscopy in combination with multivariate calibration does result in a qualitative relation for organic matter (R2=0.45) and clay content (R2=0.43) while under laboratory conditions more accurate results are obtained (R2=0.69 and 0.92, respectively). Soil moisture and vegetation cover had a negative influence on the prediction capabilities for both soil properties. Although the performance of the spectra measured in situ is not as accurate as physical analysis, the accuracy obtained is useful for rapid soil characterisation and remote sensing applications.
Spatial variation of metals and acid volatile sulfide in floodplain lake sediment
Griethuysen, C. van; Meijboom, E.W. ; Koelmans, A.A. - \ 2003
Environmental Toxicology and Chemistry 22 (2003). - ISSN 0730-7268 - p. 457 - 465.
sediment - zware metalen - zwavel - meren - stroomvlakten - ruimtelijke variatie - bodemchemie - nederland - waterbodems - gelderland - geostatistiek - sediment - heavy metals - sulfur - lakes - floodplains - spatial variation - soil chemistry - netherlands - water bottoms - gelderland - geostatistics - simultaneously extracted metals - fresh-water sediments - trace-metals - contaminated sediments - diffusion method - avs - bioavailability - toxicity - cadmium
In risk assessment of aquatic sediments, much attention is paid to the immobilizing effect of acid volatile sulfide (AVS) on trace metals. The difference of AVS and simultaneously extracted metals (SEM) gives an indication of metal availability. In floodplain sediments, where changing redox conditions occur, AVS may play a major role in determining variation in metal availability. The importance of spatial heterogeneity has been recognized in risk assessment of trace-metal-polluted sediments. However, little is known about spatial variation of available metal fractions. We studied spatial variability of sediment, environmental conditions, total contaminant concentrations, and available metals (as SEM-AVS or SEM-AVS/f(OC)) in a floodplain lake. The top 5 cm of sediment was sampled at 43 locations. Data were analyzed with correlation and principal component analysis as well as with geostatistical methods. Trace metal and SEM concentrations and most sediment characteristics were more or less constant within 10%. In contrast, AVS concentrations were much more variable and showed a strong spatial dependence due to differences in lake depth, total sulfur pools, and redox potential (Eh), which resulted in crucial differences in trace-metal availability within the lake. The spatial pattern of SEM-AVS deviates from total or normalized trace-metal patterns. This particularly has implications for risk assessment of sediments prone to dynamic hydrological conditions, where AVS concentrations are also variable in time.
Vegetation abundance in lowland flood plain lakes determined by surface area, age and connectivity
Geest, G.J. van; Roozen, F.C.J.M. ; Coops, H. ; Roijackers, R.M.M. ; Buijse, A.D. ; Peeters, E.T.H.M. ; Scheffer, M. - \ 2003
Freshwater Biology 48 (2003)3. - ISSN 0046-5070 - p. 440 - 454.
waterplanten - hydrologie - meren - eutrofiëring - oppervlaktewater - stroomvlakten - nederland - rijn - aquatic plants - hydrology - lakes - eutrophication - surface water - floodplains - netherlands - river rhine - fresh-water macrophytes - shallow eutrophic lakes - lucius l stocking - submerged macrophytes - biomanipulation tool - sediment composition - biomass - growth - depth - fish
1. We analysed the vegetation structure of 215 lakes in the flood plain of the river Lower Rhine in relation to environmental variables related to hydrological connectivity, lake morphometry, lake age and land use on adjacent land. 2. The frequency distribution of the cover of submerged macrophytes was not normal, implying that submerged macrophytes in any one lake were either scarce or abundant. 3. We observed clear water lakes with submerged macrophyte dominance over a wide range of total P concentration (0.020-0.40 mg total P L-1). 4. Multiple logistic regression indicated that the probability of dominance by submerged macrophytes decreased markedly with the surface area, depth and age of the lakes. The surface area effect occurred independently of the depth. Further, there was a negative relationship between submerged macrophyte dominance and the long-term annual duration of inundation by the river. 5. Nymphaeid cover showed a distinct optimum with respect to mean lake depth, being almost absent in lakes shallower than 0.5 m. In contrast to what was found for submerged plants, the probability of occurrence of nymphaeids increased with lake age. 6. The probability of helophyte occurrence increased with lake age, and decreased with the presence of trees, cattle grazing, surface area, use of manure and mean lake depth. 7. In all cases the critical level of one factor (e.g. mean lake depth) depended on other factors (e.g. surface area or age of lake). Thus, in the present study, small lakes tended to remain dominated by submerged macrophytes up to a greater depth than large lakes, and helophytes colonised smaller lakes in an earlier phase. 8. The effect of inundation by the river was modest. This could be because most of our lakes are rarely inundated during the growing season and experience only moderate current velocities while flooded. 9. The results have practical implications for future management of flood plains for conservation purposes. In new water bodies, macrophyte domination will be promoted if many small shallow lakes, rather than few large deep ones, are excavated.
Waterberging in combinatie met recreatie; "spannend water"
Groot, S. ; Penning, E. ; Kuin, A. ; Jókövi, E.M. - \ 2002
H2O : tijdschrift voor watervoorziening en afvalwaterbehandeling 35 (2002)8. - ISSN 0166-8439 - p. 38 - 39.
waterbeheer - water - opslag - retentie - overstromingsgebieden - inundatie - recreatie - recreatiegebieden - landgebruik - meervoudig landgebruik - landgebruiksplanning - wateropslag - hoogwaterbeheersing - stroomvlakten - overstroomde gronden - noord-holland - meervoudig ruimtegebruik - ruimtelijke ordening - waterberging - water management - water - storage - retention - bottomlands - flooding - recreation - amenity and recreation areas - land use - multiple land use - land use planning - water storage - flood control - floodplains - flooded land - noord-holland
Resultaten van een onderzoek naar de mogelijkheden voor combinatie van de functies waterberging en recreatie in Noord-Holland: waar moet je rekening mee houden; wat voor recreatie komt er; hoe zit het met de waterkwaliteit; hoe kan deze functiecombinatie worden gestimuleerd. Derde artikel in een serie van vier over het project 'Meervoudig ruimtegebruik met waterberging in Noord-Holland'
Vegetation succession in floodplain flats : inventarisation and modelling of measured data and expert judgement
Nijhof, B.S.J. - \ 2002
Wageningen : Alterra (CFR project report 5 / Alterra-rapport 529) - 52
vegetatie - plantensuccessie - stroomvlakten - inundatie - geologische sedimentatie - modellen - plantenecologische groepen - nederland - simulatiemodel - uiterwaarden - vegetation - plant succession - floodplains - flooding - geological sedimentation - models - plant ecological groups - netherlands
Literature study and expert judgement are used to develop succession schemes per vegetation structure type of the Dutch floodplain flats. The occurrence of a vegetation type is said to be mainly related to flooding duration and frequency. The third factor taken into account is the management, for example mowing or grazing. Per vegetation structure type the relation between vegetation types and time span needed for developing from one into another is given.
Belasting van de Afgedamde Maas door bestrijdingsmiddelen; een schatting van de relatieve bijdragen vanuit de uiterwaarden van de Afgedamde Maas en de polders van de Bommelerwaard
Kruijne, R. - \ 2002
Wageningen : Alterra (Alterra-rapport 395) - 91
stroomvlakten - rivieren - pesticiden - gelderland - maas - bommelerwaard - uiterwaarden - bestrijdingsmiddelen - landbouw - milieu - oppervlaktewater - tuinbouw - waterkwaliteit - waterverontreiniging - pesticides - surface water - water pollution - gelderland - river meuse - bommelerwaard - river forelands
Meetgegevens van nutriënten en bestrijdingsmiddelen zijn gebruikt om een beeld te geven van de oppervlaktewaterkwaliteit van de Afgedamde Maas, de Bommelerwaard, en de Maas. Op basis van regionale gegevens over het gebruik van bestrijdingsmiddelen in de fruitteelt-, chrysantenteelt-, rundveehouderij- en akkerbouwsector zijn emissies van stoffen naar het open water van de Bommelerwaard en de uiterwaarden van de Afgedamde Maas berekend. De verdwijning van stoffen uit het oppervlaktewater als gevolg vanafbraak en verdamping is berekend. Het restant van de geëmitteerde hoeveelheid stoffen vormt de belasting van de Afgedamde Maas. De resultaten zijn gepresenteerd op het niveau van deelgebieden en teeltsectoren.
Restoration strategies for river floodplains along large lowland rivers in Europe
Buijse, A.D. ; Coops, H. ; Staras, M. ; Jans, L.H. ; Geest, G. van; Grift, R.E. ; Ibelings, B.W. ; Oosterberg, W. ; Roozen, F.C.J.M. - \ 2002
Freshwater Biology 47 (2002). - ISSN 0046-5070 - p. 889 - 907.
stroomvlakten - rivieren - herstel - rijn - donau - floodplains - rivers - rehabilitation - river rhine - river danube
1. Most temperate rivers are heavily regulated and characterised by incised channels, aggradated floodplains and modified hydroperiods. As a consequence, former extensive aquatic/terrestrial transition zones lack most of their basic ecological functions. 2. Along large rivers in Europe and North America, various floodplain restoration or rehabilitation projects have been planned or realised in recent years. However, restoration ecology is still in its infancy and the literature pertinent to river restoration is rather fragmented. (Semi-) aquatic components of floodplains, including secondary channels, disconnected and temporary waters as well as marshes, have received little attention, despite their significant contribution to biological diversity. 3. Many rehabilitation projects were planned or realised without prior knowledge of their potential for success or failure, although, these projects greatly contributed to our present understanding of river-floodplain systems. 4. River rehabilitation benefits from a consideration of river ecosystem concepts in quantitative terms, comparison with reference conditions, historical or others, and the establishment of interdisciplinary partnerships. 5. We present examples from two large European rivers, the Danube and the Rhine, in which the role of aquatic connectivity has been extensively studied. The Danube delta with its diversity of floodplain lakes across an immense transversal gradient (up to 10 km) serves as a reference system for restoration projects along lowland sections of large rivers such as the Rhine in the Netherlands.