Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Alterations in mucosal neuropeptides in patients with irritable bowel syndrome and ulcerative colitis in remission: A role in pain symptom generation?
Keszthelyi, D. ; Troost, F.J. ; Jonkers, D.M. ; Helyes, Z. ; Hamer, H.M. ; Ludidi, S. ; Vanhoutvin, S. ; Venema, K. ; Dekker, J. ; Szolcsanyi, J. ; Masclee, A.A. - \ 2013
European Journal of Pain 17 (2013)9. - ISSN 1090-3801 - p. 1299 - 1306.
vanilloid receptor vr1 - gastrointestinal-tract - abdominal-pain - substance-p - axonal-transport - trpv1 receptor - messenger-rna - rectal mucosa - expression - disease
Background Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by chronic abdominal pain. The transient receptor potential vanilloid 1 (TRPV1) channel, which is involved in visceral pain signalling, has been shown to be up-regulated in IBS. Activation of TRPV1 leads to the release of neuropeptides, such as somatostatin and substance P (SP). We hypothesized that increased pain perception in IBS could be explained by increased transcription in TRPV1 and/or altered levels of neuropeptides. We therefore assessed the transcription of TRPV1 and the mucosal concentration of somatostatin and SP in IBS in comparison to healthy volunteers and patients with ulcerative colitis (UC) in remission as disease controls, and to ascertain their relationship to pain symptoms. Method Sigmoid colonic mucosal samples were collected from 12 patients with IBS, 34 patients with UC in remission and 9 healthy volunteers, in which groups TRPV1 mRNA levels were determined using quantitative polymerase chain reaction and neuropeptide concentrations by radioimmunoassay. Pain symptom intensity was determined by questionnaires. Results Transcription of TRPV1 as well as the concentration of neuropeptides were significantly higher in IBS, but only the former correlated with pain symptom severity. Conclusion Increased transcription of TRPV1 may provide a possible explanation for pain generation in IBS. While the neuropeptides SP and somatostatin were both found to be increased in IBS, these changes are not sufficient to explain pain generation. Pain generation in IBS is probably explained by a complex redundancy in the regulation of local nociceptive mechanisms, which remains a subject of intensive investigation.
Ethanol metabolism and its effects on the intestinal epithelial barrier
Elamin, E.E. ; Masclee, A.A. ; Dekker, J. ; Jonkers, D.M. - \ 2013
Nutrition Reviews 71 (2013)7. - ISSN 0029-6643 - p. 483 - 499.
acid ethyl-esters - caco-2 cell monolayer - alcoholic liver-disease - tight-junction barrier - induced gut leakiness - mediated acetaldehyde production - human gastrointestinal-tract - inflammatory-bowel-disease - pancreatic acinar-cells - chain kinase expression
Ethanol is widely consumed and is associated with an increasing global health burden. Several reviews have addressed the effects of ethanol and its oxidative metabolite, acetaldehyde, on the gastrointestinal (GI) tract, focusing on carcinogenic effects or alcoholic liver disease. However, both the oxidative and the nonoxidative metabolites of ethanol can affect the epithelial barrier of the small and large intestines, thereby contributing to GI and liver diseases. This review outlines the possible mechanisms of ethanol metabolism as well as the effects of ethanol and its metabolites on the intestinal barrier. Limited studies in humans and supporting in vitro data have indicated that ethanol as well as mainly acetaldehyde can increase small intestinal permeability. Limited evidence also points to increased colon permeability following exposure to ethanol or acetaldehyde. In vitro studies have provided several mechanisms for disruption of the epithelial barrier, including activation of different cell-signaling pathways, oxidative stress, and remodeling of the cytoskeleton. Modulation via intestinal microbiota, however, should also be considered. In conclusion, ethanol and its metabolites may act additively or even synergistically in vivo. Therefore, in vivo studies investigating the effects of ethanol and its byproducts on permeability of the small and large intestines are warranted.
Sustainability assessment of salmonid feed using energy, classical exergy and eco-exergy analysis
Draganovic, V. ; Jorgensen, S.E. ; Boom, R.M. ; Jonkers, J. ; Goot, A.J. van der - \ 2013
Ecological Indicators 34 (2013). - ISSN 1470-160X - p. 277 - 289.
krill euphausia-superba - life-cycle assessment - environmental impacts - production systems - farmed salmon - ethanol - organisms - products - chains - wheat
Reduction of the environmental impact of feed products is of paramount importance for salmon farming. This article explores the potential to compare three thermodynamically based ecological indicators. The environmental impact of partial replacement of fish meal (FM) and fish oil with alternative ingredients was investigated using energy, classical exergy and eco-exergy analysis. Seven hypothetical feeds were formulated: one with high levels of FM and fish oil, four feeds based on plant ingredients, one containing krill meal, and one based on algae-derived products. Analysis included cultivation of crops and algae, fishing for fish and krill, industrial processing of these ingredients and production of complete fish feed. Because most harvested products are refined in multiple product outputs that have good value to society, two scenarios were compared. In the base case scenario, no allocation of co-products was used and all the environmental costs were ascribed to one specific co-product. Co-product allocation by mass was used in the second scenario; this is considered to be the preferred scenario because it accurately reflects the individual contributions of the co-products to the environmental impact of the feed products. For this scenario, the total energy consumption for a fish-based diet was 14,500 MJ, which was similar to a krill diet (15,600 MJ), about 15–31% higher than plant-based diets, and 9% higher than an algae diet. Substituting FM and fish oil with alternative ingredients resulted in minor changes in total classical exergy degradation (2–16% difference). The calculations based on energy only consider the energy conservation based on the First Law of Thermodynamics, whereas those based on classical exergy also takes the Second Law of Thermodynamics into account; energy that can do work is distinguished from energy that is lost as heat to the environment. The calculations based on eco-exergy consider the total loss of work energy in the environment including the work energy associated with the information embodied in the genomes of organisms. The diet based on fishery-derived ingredients was the highest total work energy consumer compared with plant-based diets (24–30% greater), the diet containing krill meal (25% greater), and the algae diet (four times higher). Thus, reducing FM and fish oil levels in fish feed can contribute significantly to more sustainable aquaculture. In particular, algae-derived products in aquafeeds could drastically decrease environmental costs in the future.
Wheat gluten in extruded fish feed: Effects on morphology and on physical and functional properties
Draganovic, V. ; Goot, A.J. van der; Boom, R.M. ; Jonkers, J. - \ 2013
Aquaculture Nutrition 19 (2013)6. - ISSN 1353-5773 - p. 845 - 859.
structural characteristics - lysine supplementation - salmonid feeds - rainbow-trout - oil uptake - products - protein - meal - microstructure - digestibility
This article focuses on understanding the role of vital wheat gluten on the structural parameters of extruded fish feed and its correlation to the physical and functional properties. Gluten–soy protein concentrate blends with five gluten concentrations (0–200 g kg-1) were produced. An abrupt reduction in oil uptake was observed with the 200 g gluten kg-1 blend. Inclusion of gluten from 100 to 200 g kg-1 resulted in unacceptable product properties. Sinking of feed pellets with 0 and 50 g gluten kg-1 was 100%, whereas only 36% of pellets with 200 g gluten kg-1 sank. We suspect that this is due to a relationship between morphological structure and oil impregnation during coating of feeds. The addition of gluten at 200 g kg-1 gave a smoother and non-porous outer surface. Pellets without gluten had a larger number of cells that were smaller than 200 µm (P <0.05) compared with pellets with 100 and 200 g gluten kg-1. More spherical cell shapes (P <0.01) and a compact structure were favoured in the presence of gluten. The closed porosity increased (P <0.05), whereas interconnectivity between pores decreased (P <0.01), with increasing gluten content from 0 to 200 g kg-1. The effects of the addition of gluten are probably related to the film-forming properties of gluten.
Microbiota conservation and BMI signatures in adult monozygotic twins
Tims, S. ; Derom, C. ; Jonkers, D.M.A.E. ; Vlietinck, R. ; Saris, W.H. ; Kleerebezem, M. ; Vos, W.M. de; Zoetendal, E.G. - \ 2013
ISME Journal 7 (2013). - ISSN 1751-7362 - p. 707 - 717.
human gut - crohns-disease - phylogenetic microarray - intestinal microbiota - identical-twins - sp nov. - bacteria - obesity - host - ecology
The human gastrointestinal (GI) tract microbiota acts like a virtual organ and is suggested to be of great importance in human energy balance and weight control. This study included 40 monozygotic (MZ) twin pairs to investigate the influence of the human genotype on GI microbiota structure as well as microbial signatures for differences in body mass index (BMI). Phylogenetic microarraying based on 16S rRNA genes demonstrated that MZ twins have more similar microbiotas compared with unrelated subjects (P
Does acute tryptophan depletion affect peripheral serotonin metabolism in the intestine?
Keszthelyi, D. ; Troost, F.J. ; Jonkers, D.M. ; Donkelaar, E.L. van; Dekker, J. ; Buurman, W.A. ; Masclee, A.A. - \ 2012
American Journal of Clinical Nutrition 95 (2012)3. - ISSN 0002-9165 - p. 603 - 608.
5-hydroxyindoleacetic acid - gastrointestinal-tract - cerebrospinal-fluid - brain - permeability - depression - cortisol - reuptake - humans - lumbar
Background: Serotonin (5-hydroxytryptamine; 5-HT), a tryptophan metabolite, plays an important regulatory role in the human central nervous system and in the gastrointestinal tract. Acute tryptophan depletion (ATD) is currently the most widely established method to investigate 5-HT metabolism. Objective: The aim of this study was to assess the effect of an acute decrease in the systemic availability of tryptophan on intestinal 5-HT metabolism and permeability. Design: Thirty-three healthy volunteers (17 with ATD, 3 of whom dropped out; 16 placebo) participated in this randomized placebo-controlled study. Plasma and duodenal mucosal concentrations of 5-HT, 5-hydroxyindoleacetic acid (5-HIAA), and kynurenic acid (KA) were measured by HPLC-mass spectrometry. Intestinal barrier function was assessed with a multisugar plasma test, and analysis of tight junction transcription was performed in duodenal biopsy samples obtained by gastroduodenoscopy. Results: Mucosal 5-HT, 5-HIAA, and KA concentrations remained unaltered by ATD. In contrast, ATD significantly decreased plasma 5-HT (P <0.05) and 5-HIAA (P <0.0001) concentrations. After endoscopy, a significant increase in plasma 5-HT concentrations was observed in the placebo group (P = 0.029) compared with the ATD group. Moreover, a significant increase in plasma KA concentrations over time was found in the placebo group (P <0.05). No changes in intestinal barrier function were observed. Conclusions: An acute decrease in precursor availability does not affect mucosal concentrations of serotonergic metabolites, in contrast with systemic concentrations. ATD alters biochemical responses to acute stress from the endoscopic examination reflected by lower 5-HT concentrations. Changes in 5-HT concentrations were paralleled by alterations in KA concentrations, which suggest competition between the 2 metabolic pathways for the mutual precursor. This trial was registered at clinicaltrials.gov as NCT00731003. Am J Clin Nutr 2012;95:603-8.
Effector identification in the lettuce on Tight Junction Integrity: In Vitro Study in a Three Dimensional Intestinal Epithelial Cell Culture Model
Elamin, E. ; Jonkers, D. ; Juuti-Uusitalo, K. ; IJzendoorn, S. van; Troost, F. ; Duimel, H. ; Broers, J. ; Verheyen, F. ; Dekker, J. ; Masclee, A. - \ 2012
PLoS ONE 7 (2012)4. - ISSN 1932-6203
paracellular permeability - liver-disease - alcohol-consumption - induced increase - molecular-basis - leaky gut - barrier - tissue - monolayer - complex
Background: Intestinal barrier dysfunction and translocation of endotoxins are involved in the pathogenesis of alcoholic liver disease. Exposure to ethanol and its metabolite, acetaldehyde at relatively high concentrations have been shown to disrupt intestinal epithelial tight junctions in the conventional two dimensional cell culture models. The present study investigated quantitatively and qualitatively the effects of ethanol at concentrations detected in the blood after moderate ethanol consumption, of its metabolite acetaldehyde and of the combination of both compounds on intestinal barrier function in a three-dimensional cell culture model. Methods and Findings: Caco-2 cells were grown in a basement membrane matrix (Matrigel (TM)) to induce spheroid formation and were then exposed to the compounds at the basolateral side. Morphological differentiation of the spheroids was assessed by immunocytochemistry and transmission electron microscopy. The barrier function was assessed by the flux of FITC-labeled dextran from the basal side into the spheroids' luminal compartment using confocal microscopy. Caco-2 cells grown on Matrigel assembled into fully differentiated and polarized spheroids with a central lumen, closely resembling enterocytes in vivo and provide an excellent model to study epithelial barrier functionality. Exposure to ethanol (10-40 mM) or acetaldehyde (25-200 mu M) for 3 h, dose-dependently and additively increased the paracellular permeability and induced redistribution of ZO-1 and occludin without affecting cell viability or tight junction-encoding gene expression. Furthermore, ethanol and acetaldehyde induced lysine residue and microtubules hyperacetylation. Conclusions: These results indicate that ethanol at concentrations found in the blood after moderate drinking and acetaldehyde, alone and in combination, can increase the intestinal epithelial permeability. The data also point to the involvement of protein hyperacetylation in ethanol- and acetaldehyde-induced loss of tight junctions integrity.
Towards sustainable fish feed production using novel protein sources
Draganovic, V. ; Goot, A.J. van der; Boom, R.M. ; Jonkers, J. - \ 2012
Duurzaam Doenderzoek in de Zeeuwse delta: Ervaringen met het kwantificeren van ecosysteemdiensten
Smit, A. ; Verzandvoort, S.J.E. ; Jonkers, W. - \ 2012
Bodem (2012)4. - ISSN 0925-1650 - p. 30 - 33.
bodem - landschap - ecosysteemdiensten - bodemwater - wateropslag - duurzaamheid (sustainability) - zeeland - soil - landscape - ecosystem services - soil water - water storage - sustainability
Voor het project Doenderzoek is voor elf ecosysteemdiensten in Zeeland de potentïële levering van deze diensten in kaart gebracht. Tijdens de uitwerking bleken definities, benutting van diensten, databeschikbaarheid en schaal belangrijke factoren te zijn. In dit artikel laten we zien welke lessen we hebben geleerd.
Meer water met regelbare drainage?
Stuyt, L.C.P.M. ; Bolt, F.J.E. van der; Snellen, W.B. ; Groenendijk, P. ; Schipper, P.N.M. ; Harmsen, J. ; Bakel, P.J.T. van; Ruijtenberg, R. ; Jonkers, D.A. ; Peerboom, J.M.P.M. ; Buck, A.J. de; Huinink, M. ; Rijken, M. ; Straat, A.A. van der; Talsma, M.J.G. - \ 2012
Amersfoort : Stowa (Rapport / STOWA 2012-33) - ISBN 9789057735707 - 60
drainage - grondwaterstand - agrarische bedrijfsvoering - peilbeheer - groundwater level - farm management - water level management
Dit rapport geeft aan de hand van resultaten van vijf Nederlandse praktijkproeven inzicht in de mogelijkheden van regelbare of peilgestuurde drainage. Deze vorm van drainage - waarbij boeren de grondwaterstand op hun percelen flexibel kunnen regelen - houdt in tegenstelling tot conventionele drainage veel beter rekening met de uiteenlopende wensen en behoeften vanuit de landbouw, natuur, milieu en waterbeheer. Dit kan de realisatie van waterkwaliteits- en waterkwantiteitsdoelstellingen door waterschappen bevorderen en tegelijkertijd de bedrijfsvoering van agrariërs verbeteren.
Vuurwerk & vogels provincie Utrecht : afwegingskader voor vergunningverlening ten aanzien van vuurwerkevenementen in en nabij Utrechtse Vogelrichtlijngebieden inclusief twee casestudies
Ottburg, F.G.W.A. ; Molenaar, J.G. de; Jonkers, D.A. ; Henkens, R.J.H.G. - \ 2012
Wageningen : Alterra (Alterra-rapport 2347) - 40
publieksevenementen - festivals - licenties - nadelige gevolgen - vogels - wildbescherming - geluidshinder - natura 2000 - utrecht - spectator events - licences - adverse effects - birds - wildlife conservation - noise pollution
In Alterra rapport 1694 ‘Vuurwerk & Vogels; afwegingskader voor vergunningverlening ten aanzien van vuurwerkevenementen in en nabij Brabantse Vogelrichtlijngebieden’ wordt een afwegingskader voor vergunningverlening voorvuurwerkevenementen in en nabij Brabantse Vogelrichtlijngebieden gegeven. De belangrijkste uitkomsten van deze studie worden samengevat in de tabellen 7 en 8, namelijk ‘Vuurwerktypen en beslisregels met betrekking tot gebruik bij evenementen van Vogelrichtlijngebieden voor de broedvogels en niet-broedvogels van Brabantse Natura 2000-gebieden’. De provincie Utrecht heeft Alterra verzocht om de tabellen 7 en 8 uit rapport 1694 uit te breiden met tien broedvogels en één niet-broedvogel voor de Utrechtse Natura 2000-gebieden en Beschermde Natuurmonumenten in de provincie Utrecht. Naast de gevraagde uitbreiding van vogelsoorten is Alterra ook verzocht om twee casestudies te behandelen; een vuurwerkevenement in de uiterwaard bij Rhenen en een vuurwerkevenement in Maarssen nabij de Oostelijke Vechtplassen.
Duurzaam doenderzoek in de Zeeuwse delta : Ecosysteemdiensten in de praktijk : deelresultaat 4.1 : Verslag van de werkbijeenkomst "De waardering van ecosysteemdiensten (doenderdag 2), Deelresultaat 4.2: Kansen voor duurzaam gebruik van bodem, ondergrond en landschap op basis van voorbeelprojecten
Verzandvoort, S.J.E. ; Smit, A. ; Jonkers, W. ; Baaren, E.S. ; Braat, L.C. - \ 2012
Wageningen : Alterra, Wageningen-UR - 52
ecosysteemdiensten - projecten - bodembeheer - natuurbeheer - landschapsbeheer - inventarisaties - zeeland - ecosystem services - projects - soil management - nature management - landscape management - inventories
Reflectie op de rol van het project Duurzaam Doenderzoek in de Zeeuwse Delta in het werk aan duurzame ontwikkeling van de Provincie Zeeland. Duurzaamheid vormgeven via het concept van ecosysteemdiensten. Het bijzondere van dit project zit niet in de theoretische benadering vanuit bodem en natuur, maar in het feit dat we het gebeurt, en wel met mensen uit de praktijk. Daardoor adresseren we ecosysteemdiensten in de richting van de praktijk. Partijen binnenhalen om mee te denken geeft een interactie die niet mogelijk zou zijn alleen redenerend vanuit het eigen beleidsveld of sector.
Impacts on biomass, nutrients and water
Schmidt, P. ; Poels, R.L.H. ; Ketner, P. ; Jonkers, W.B.J. - \ 2011
In: Sustainable Management of Tropical Rainforests / Werger, M.J.A., Paramaribo : Tropenbos International (Tropenbos Series 25) - ISBN 9789051131017 - p. 100 - 135.
Impacts on forest structure and plant diversity
Schmidt, P. ; Jonkers, W.B.J. ; Ketner, P. ; Dijn, B.P.E. De - \ 2011
In: Sustainable Management of Tropical Rainforests / Werger, M.J.A., Paramaribo : Tropenbos International (Tropenbos Series 25) - ISBN 9789051131017 - p. 74 - 99.
Tree growth, recruitment and mortality after logging and refinement
Jonkers, W.B.J. - \ 2011
In: Sustainable Management of Tropical Rainforests / Werger, M.J.A., Paramaribo : Tropenbos International (Tropenbos Series 25) - ISBN 9789051131017 - p. 46 - 73.
The CELOS Management System: concept, treatments and costs
Jonkers, W.B.J. ; Hendrison, J. - \ 2011
In: Sustainable Management of Tropical Rainforests / Werger, M.J.A., Paramaribo : Tropenbos International (Tropenbos Series 25) - ISBN 9789051131017 - p. 29 - 45.
Prospects for the CELOS Management System (Part III: Conclusions and recommendations)
Jonkers, W.B.J. ; Graaf, N.R. de; Hendrison, J. ; Ketner, P. ; Mohren, G.M.J. ; Schmidt, P. ; Hout, P. van der; Kanten, R.F. ; Zagt, R.J. - \ 2011
In: Sustainable Management of Tropical Rainforests - The CELOS Management System / Werger, M.J.A., Paramaribo : Tropenbos International, Paramaribo, Suriname (Tropenbos Series 25) - ISBN 9789051131017 - p. 257 - 263.
The FRP1 F-box gene has different functions in sexuality, pathogenicity and metabolism in three fungal pathogens
Jonkers, W. ; Kan, J.A.L. van; Tijm, P. ; Lee, Y.W. ; Tudzynski, P. ; Rep, M. ; Michielse, C.B. - \ 2011
Molecular Plant Pathology 12 (2011)6. - ISSN 1464-6722 - p. 548 - 563.
vascular wilt fungus - fusarium-oxysporum - botrytis-cinerea - gibberella-zeae - map kinase - reduced pathogenicity - filamentous fungi - protein-kinase - g-alpha - virulence
Plant-pathogenic fungi employ a variety of infection strategies; as a result, fungi probably rely on different sets of proteins for successful infection. The F-box protein Frp1, only present in filamentous fungi belonging to the Sordariomycetes, Leotiomycetes and Dothideomycetes, is required for nonsugar carbon catabolism and pathogenicity in the root-infecting fungus Fusarium oxysporum. To assess the role of Frp1 in other plant-pathogenic fungi, FRP1 deletion mutants were generated in Fusarium graminearum and Botrytis cinerea, and their phenotypes were analysed. Deletion of FgFRP1 in F. graminearum led to impaired infection of barley roots, but not of aerial plant parts. Deletion of BcFRP1 in B. cinerea did not show any effect on pathogenicity. Sexual reproduction, however, was impaired in both F. graminearum and B. cinerea FRP1 deletion mutants. The mutants of all three fungi displayed different phenotypes when grown on an array of carbon sources. The F. oxysporum and B. cinerea deletion mutants showed opposite growth phenotypes on sugar and nonsugar carbon sources. Replacement of FoFRP1 in F. oxysporum with the B. cinerea BcFRP1 resulted in the restoration of pathogenicity, but also in a switch from impaired growth on nonsugar carbon sources to impaired growth on sugar carbon sources. This effect could be ascribed in part to the B. cinerea BcFRP1 promoter sequence. In conclusion, the function of the F-box protein Frp1, despite its high sequence conservation, is not conserved between different fungi, leading to differential requirements for pathogenicity and carbon source utilization.
Assessment of the effects of fish meal, wheat gluten, soy protein concentrate and feed moisture on extruder system parameters and the technical quality of fish feed
Draganovic, V. ; Goot, A.J. van der; Boom, R.M. ; Jonkers, J. - \ 2011
Animal Feed Science and Technology 165 (2011)3-4. - ISSN 0377-8401 - p. 238 - 250.
trout oncorhynchus-mykiss - extrusion conditions - physical-properties - rainbow-trout - aquaculture feeds - screw extrusion - replacement - products - cooking - starch
Evaluation of feed ingredient functionality plays a vital role in modern fish feed manufacturing practice. The aim of this study was to examine the extrusion behaviour of blends containing alternative protein sources from plant origin to fish meal (FM), such as wheat gluten (WG) and soy protein concentrate (SPC), and the consequences for the physical attributes of the resulting feed extrudates. A mixture design was applied, varying the levels of protein sources included in the formulation from 50 to 450 g kg-1. Each diet was produced with added feed moisture content of 20, 26 and 32 g/100 g (wet basis). The partial least squares regression models were fitted and their performance was evaluated on the basis of R2 and the root mean squared error of cross-validation over the complete data set. A higher inclusion level of FM in the diet decreased the values of the extruder system parameters, such as torque, pressure at the die and melt temperature. In contrast, inclusion of SPC significantly increased the values of these extruder-related parameters. The viscoelastic properties of WG gave higher radial expansion; FM showed the opposite effect. The results show that the feed moisture was the dominant factor for extrudate density and oil absorption capacity. Products with higher breaking strength were observed with increasing levels of WG and SPC. Combining the product requirements for both extrudate density and hardness showed that the largest optimal compositional range is available at low feed moisture content. However, maximum FM replacement is possible at high feed moisture content
Eemuiterwaarden Bruggematen en Wolkenberg : inventarisatie van het voorkomen van amfibieën en de ringslang in het kader van inrichtingsmaatregelen
Ottburg, F.G.W.A. ; Jonkers, D.A. - \ 2011
Wageningen : Alterra (Alterra-rapport 2159) - 36
uiterwaarden - reptielen - amphibia - habitatverbindingszones - habitats - natuurbeheer - inventarisaties - eemland - utrecht - river forelands - reptiles - habitat corridors - nature management - inventories
Natuurmonumenten heeft in het beheergebied Eemland het plan om inrichtingsmaatregelen uit te voeren in de uiterwaarden Bruggematen en Wolkenberg. Alterra en ecologisch adviesbureau Greendesk is gevraagd om specifiek een inventarisatie uit te voeren naar het voorkomen van amfibieën en ringslang in beide uiterwaarden. Hierin komen weinig soorten amfibieën voor en de aantallen daarvan zijn laag. Bijzonder is de aanwezigheid van rugstreeppadlarven in Wolkenberg. Tijdens het onderzoek zijn geen ringslangen vastgesteld. De dichtstbijzijnde bekende populaties komen voor in de omgeving van de Stichtse Brug en De Birkt. Aanbevolen wordt om het tussenliggende gebied in kaart te brengen. Waar bevindt zich geschikt habitat voor de ringslang? In een vervolg hierop kan worden overwogen waar en hoeveel stapstenen er nodig zijn om beide populaties te verbinden. Naast de formele opdracht zijn ook andere faunagroepen meegenomen tijdens de inventarisaties. Dit rapport sluit af met het hoofdstuk ‘Aanbevelingen voor beheer en inrichting’.
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