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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    Het Landelijk Waterkwaliteitsmodel : Uitbreiding van het Nationaal Water Model met waterkwaliteit ten behoeve van berekeningen voor nutriënten
    Bolt, F.J.E. van der; Kroon, T. ; Groenendijk, P. ; Renaud, L.V. ; Roovaart, J. van den; Janssen, C.M.C.M. ; Loos, S. ; Cleij, P. ; Linden, A. van den; Marsman, A. - \ 2020
    Wageningen : Wageningen Environmental Research (Wageningen Environmental Research rapport 3005) - 220
    De stuurgroep Nationaal Water Model heeft de opdracht gegeven een landelijk waterkwaliteitsmodel nutriënten te ontwikkelen. Dit Landelijk WaterKwaliteitsModel (LWKM) is gebaseerd op de recentste data, gebruikt de resultaten van het Landelijk hydrologisch Model en bouwt waar mogelijk voort op of maakt gebruik van onderdelen van eerdere modelinstrumenten als STONE en het Landelijk KRW-Verkenner Model (LKM). Dit rapport beschrijft de opzet, de realisatie, de gebruikte invoergegevens, de initialisatie, de kalibratie, de toetsing en resultaten van de eerste versie van het LWKM
    Biodiversity increases multitrophic energy use efficiency, flow and storage in grasslands
    Buzhdygan, Oksana Y. ; Meyer, Sebastian T. ; Weisser, Wolfgang W. ; Eisenhauer, Nico ; Ebeling, Anne ; Borrett, Stuart R. ; Buchmann, Nina ; Cortois, Roeland ; Deyn, Gerlinde B. De; Kroon, Hans de; Gleixner, Gerd ; Hertzog, Lionel R. ; Hines, Jes ; Lange, Markus ; Mommer, Liesje ; Ravenek, Janneke ; Scherber, Christoph ; Scherer-Lorenzen, Michael ; Scheu, Stefan ; Schmid, Bernhard ; Steinauer, Katja ; Strecker, Tanja ; Tietjen, Britta ; Vogel, Anja ; Weigelt, Alexandra ; Petermann, Jana S. - \ 2020
    Nature Ecology & Evolution 4 (2020)4. - ISSN 2397-334X - p. 393 - 405.

    The continuing loss of global biodiversity has raised questions about the risk that species extinctions pose for the functioning of natural ecosystems and the services that they provide for human wellbeing. There is consensus that, on single trophic levels, biodiversity sustains functions; however, to understand the full range of biodiversity effects, a holistic and multitrophic perspective is needed. Here, we apply methods from ecosystem ecology that quantify the structure and dynamics of the trophic network using ecosystem energetics to data from a large grassland biodiversity experiment. We show that higher plant diversity leads to more energy stored, greater energy flow and higher community-energy-use efficiency across the entire trophic network. These effects of biodiversity on energy dynamics were not restricted to only plants but were also expressed by other trophic groups and, to a similar degree, in aboveground and belowground parts of the ecosystem, even though plants are by far the dominating group in the system. The positive effects of biodiversity on one trophic level were not counteracted by the negative effects on adjacent levels. Trophic levels jointly increased the performance of the community, indicating ecosystem-wide multitrophic complementarity, which is potentially an important prerequisite for the provisioning of ecosystem services.

    Adherence to the Dutch dietary guidelines and 15-year incidence of heart failure in the EPIC-NL cohort
    Harbers, Marjolein C. ; Kroon, Marleen A. de; Boer, Jolanda M.A. ; Asselbergs, Folkert W. ; Geleijnse, Johanna M. ; Verschuren, Monique W. ; Schouw, Yvonne T. van der; Sluijs, Ivonne - \ 2020
    European Journal of Nutrition (2020). - ISSN 1436-6207
    Dietary patterns - Dutch dietary guidelines - Dutch Healthy Diet 2015 Index - Heart failure

    Purpose: A healthy diet may contribute to the primary prevention of heart failure (HF), but evidence is still inconclusive. We aimed to study the association between adherence to the Dutch dietary guidelines and incidence of HF. Methods: We studied 37,468 participants aged 20–70 years and free of HF at baseline from the EPIC-NL cohort. At baseline (1993–1997), data were collected on demographics, lifestyle, and presence of chronic diseases. Dietary intake was assessed using a 178-item validated food frequency questionnaire. Dietary intake data were used to calculate scores on the Dutch Healthy Diet 2015 Index (DHD15-index) measuring adherence to the Dutch dietary guidelines. The DHD15-index is based on the average daily intake of 14 food groups resulting in a total score ranging between 0 and 140, with higher scores indicating better adherence. HF morbidity and mortality during follow-up were ascertained through linkage with national registries. Cox proportional hazards analysis was used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs) for the association between DHD15 adherence and HF risk, adjusting for sociodemographic and lifestyle characteristics. Results: The average score on the DHD15-index was 71 (SD = 15). During a median follow-up of 15.2 years (IQR 14.1–16.5), 674 HF events occurred. After adjustment for demographic and lifestyle characteristics, higher scores on the DHD15-index were associated with lower risk of HF (HRQ4vsQ1 0.73; 95% CI 0.58–0.93; Ptrend 0.001). Conclusion: In a large Dutch population of middle-aged adults, higher adherence to the Dutch dietary guidelines was associated with lower risk of HF.

    International scientists formulate a roadmap for insect conservation and recovery
    Harvey, Jeffrey A. ; Heinen, Robin ; Armbrecht, Inge ; Basset, Yves ; Baxter-Gilbert, James H. ; Bezemer, T.M. ; Böhm, Monika ; Bommarco, Riccardo ; Borges, Paulo A.V. ; Cardoso, Pedro ; Clausnitzer, Viola ; Cornelisse, Tara ; Crone, Elizabeth E. ; Dicke, Marcel ; Dijkstra, Klaas Douwe B. ; Dyer, Lee ; Ellers, Jacintha ; Fartmann, Thomas ; Forister, Mathew L. ; Furlong, Michael J. ; Garcia-Aguayo, Andres ; Gerlach, Justin ; Gols, Rieta ; Goulson, Dave ; Habel, Jan Christian ; Haddad, Nick M. ; Hallmann, Caspar A. ; Henriques, Sérgio ; Herberstein, Marie E. ; Hochkirch, Axel ; Hughes, Alice C. ; Jepsen, Sarina ; Jones, T.H. ; Kaydan, Bora M. ; Kleijn, David ; Klein, Alexandra Maria ; Latty, Tanya ; Leather, Simon R. ; Lewis, Sara M. ; Lister, Bradford C. ; Losey, John E. ; Lowe, Elizabeth C. ; Macadam, Craig R. ; Montoya-Lerma, James ; Nagano, Christopher D. ; Ogan, Sophie ; Orr, Michael C. ; Painting, Christina J. ; Pham, Thai Hong ; Potts, Simon G. ; Rauf, Aunu ; Roslin, Tomas L. ; Samways, Michael J. ; Sanchez-Bayo, Francisco ; Sar, Sim A. ; Schultz, Cheryl B. ; Soares, António O. ; Thancharoen, Anchana ; Tscharntke, Teja ; Tylianakis, Jason M. ; Umbers, Kate D.L. ; Vet, Louise E.M. ; Visser, Marcel E. ; Vujic, Ante ; Wagner, David L. ; Wallis DeVries, Michiel F. ; Westphal, Catrin ; White, Thomas E. ; Wilkins, Vicky L. ; Williams, Paul H. ; Wyckhuys, Kris A.G. ; Zhu, Zeng Rong ; Kroon, Hans de - \ 2020
    Nature Ecology & Evolution 4 (2020)4. - ISSN 2397-334X - p. 174 - 176.
    A PXY-Mediated Transcriptional Network Integrates Signaling Mechanisms to Control Vascular Development in Arabidopsis
    Smit, Margot ; Mcgregor, Shauni ; Sun, Heng ; Gough, Catherine ; Bågman, Anne-Maarit ; Soyars, Cara L. ; Kroon, Johan T.M. ; Gaudinier, Allison ; Williams, Clara J. ; Yang, Xiyan ; Nimchuk, Zachary L. ; Weijers, Dolf ; Turner, Simon R. ; Brady, Siobhan M. ; Etchells, Peter - \ 2020
    The Plant Cell 32 (2020)2. - ISSN 1040-4651
    Vascular meristems generate the majority of biomass in higher plants. They constitute a bifacial stem cell population from which xylem and phloem are specified on opposing sides by positional signals. The PHLOEM INTERCALATED WITH XYLEM (PXY) receptor kinase promotes vascular cell division and organisation. However, how these functions are specified and integrated is unknown. Here, a putative PXY-mediated transcriptional regulatory network comprised of 690 transcription factor-promoter interactions was mapped. Among these interactions was a feed-forward loop containing transcription factors WUSCHEL HOMEOBOX RELATED 14 (WOX14) and TARGET OF MONOPTEROS 6 (TMO6), which each regulate the expression of a third transcription factor, LATERAL ORGAN BOUNDARIES DOMAIN 4 (LBD4). PXY signalling in turn regulates the WOX14, TMO6, LBD4 loop to control vascular proliferation. Genetic interaction between LBD4 and PXY suggests that LBD4 marks the phloem-procambium boundary, thus defining the shape of the vascular bundle. These data collectively support a novel mechanism that influences recruitment of cells into the phloem lineage, and defines the role of PXY signalling in this context to the arrangement of vascular tissue.
    Limited evidence for spatial resource partitioning across temperate grassland biodiversity experiments
    Barry, Kathryn E. ; Ruijven, Jasper van; Mommer, Liesje ; Bai, Yongfei ; Beierkuhnlein, Carl ; Buchmann, Nina ; Kroon, Hans de; Ebeling, Anne ; Eisenhauer, Nico ; Guimarães-Steinicke, Claudia ; Hildebrandt, Anke ; Isbell, Forest ; Milcu, Alexandru ; Neßhöver, Carsten ; Reich, Peter B. ; Roscher, Christiane ; Sauheitl, Leopold ; Scherer-Lorenzen, Michael ; Schmid, Bernhard ; Tilman, David ; Felten, Stefanie von; Weigelt, Alexandra - \ 2020
    Ecology 101 (2020)1. - ISSN 0012-9658
    grassland - niche complementarity - niche partitioning - productivity - resource uptake - resources - standing root biomass

    Locally, plant species richness supports many ecosystem functions. Yet, the mechanisms driving these often-positive biodiversity–ecosystem functioning relationships are not well understood. Spatial resource partitioning across vertical resource gradients is one of the main hypothesized causes for enhanced ecosystem functioning in more biodiverse grasslands. Spatial resource partitioning occurs if species differ in where they acquire resources and can happen both above- and belowground. However, studies investigating spatial resource partitioning in grasslands provide inconsistent evidence. We present the results of a meta-analysis of 21 data sets from experimental species-richness gradients in grasslands. We test the hypothesis that increasing spatial resource partitioning along vertical resource gradients enhances ecosystem functioning in diverse grassland plant communities above- and belowground. To test this hypothesis, we asked three questions. (1) Does species richness enhance biomass production or community resource uptake across sites? (2) Is there evidence of spatial resource partitioning as indicated by resource tracer uptake and biomass allocation above- and belowground? (3) Is evidence of spatial resource partitioning correlated with increased biomass production or community resource uptake? Although plant species richness enhanced community nitrogen and potassium uptake and biomass production above- and belowground, we found that plant communities did not meet our criteria for spatial resource partitioning, though they did invest in significantly more aboveground biomass in higher canopy layers in mixture relative to monoculture. Furthermore, the extent of spatial resource partitioning across studies was not positively correlated with either biomass production or community resource uptake. Our results suggest that spatial resource partitioning across vertical resource gradients alone does not offer a general explanation for enhanced ecosystem functioning in more diverse temperate grasslands.

    Suiker in drinkpakjes: Chocomel spant de kroon
    Vet, Emely de - \ 2019
    Effects of extreme rainfall events are independent of plant species richness in an experimental grassland community
    Padilla, Francisco M. ; Mommer, Liesje ; Caluwe, Hannie de; Smit-Tiekstra, Annemiek E. ; Visser, Eric J.W. ; Kroon, Hans de - \ 2019
    Oecologia 191 (2019)1. - ISSN 0029-8549 - p. 177 - 190.
    Biodiversity - Climate change - Drought - Overyielding - Resistance - Roots - Stability

    Global climate models predict more frequent periods of drought stress alternated by heavier, but fewer rainfall events in the future. Biodiversity studies have shown that such changed drought stress may be mitigated by plant species richness. Here, we investigate if grassland communities, differing in species richness, respond differently to climatic extremes within the growing season. In a 3-year outdoor mesocosm experiment, four grassland species in both monoculture and mixture were subjected to a rainfall distribution regime with two levels: periods of severe drought in the summer intermitted by extreme rainfall events versus regular rainfall over time. Both treatments received the same amount of water over the season. Extreme rainfall combined with drought periods resulted in a 15% decrease in aboveground biomass in the second and third year, compared to the regular rainfall regime. Root biomass was also reduced in the extreme rainfall treatment, particularly in the top soil layer (− 40%). All species developed higher water use efficiencies (less negative leaf δ13C) in extreme rainfall than in regular rainfall. These responses to the rainfall/drought treatment were independent of species richness, although the mixtures were on an average more productive in terms of biomass than the monocultures. Our experimental results suggest that mixtures are similarly able to buffer these within-season rainfall extremes than monocultures, which contrasts with findings in the studies on natural droughts. Our work demonstrates the importance of investigating the interactions between rainfall distribution and drought periods for understanding effects of climate change on plant community performance.

    Above- and belowground overyielding are related at the community and species level in a grassland biodiversity experiment
    Barry, Kathryn E. ; Weigelt, Alexandra ; Ruijven, Jasper van; Kroon, Hans de; Ebeling, Anne ; Eisenhauer, Nico ; Gessler, Arthur ; Ravenek, Janneke M. ; Scherer-Lorenzen, Michael ; Oram, Natalie J. ; Vogel, Anja ; Wagg, Cameron ; Mommer, Liesje - \ 2019
    In: Advances in Ecological Research / Eisenhauer, N., Bohan, D.A., Dumbrell, A.J., Academic Press Inc. (Advances in Ecological Research ) - ISBN 9780081029121 - p. 55 - 89.
    Biodiversity-ecosystem functioning - Biomass allocation - Functional diversity - Jena experiment - Light competition - Plant traits - Root biomass - Root:Shoot ratio - Shoot biomass - Species richness

    Plant species richness positively affects plant productivity both above- and belowground. While this suggests that they are related at the community level, few studies have calculated above- and belowground overyielding simultaneously. It thus remains unknown whether above- and belowground overyielding are correlated. Moreover, it is unknown how belowground community level overyielding translates to the species level. We investigated above- and belowground overyielding in the Jena Trait-Based Biodiversity Experiment, at both the community and species level and across two 8-species pools. We found that above- and belowground overyielding were positively correlated at the community level and at the species level—for seven out of the 13 investigated species. Some plant species performed better in mixtures compared to monocultures and others performed worse, but the majority did so simultaneously above- and belowground. However, plants invested more in aboveground overyielding than belowground. Based on this disproportional investment in overyielding aboveground, we conclude that light was more limiting than belowground resources in the present study, which requires individual species to compete more for light than for belowground resources.

    Combining agro-ecological functions in grass-clover mixtures
    Haas, Brechtje R. de; Hoekstra, Nyncke J. ; Schoot, Jan R. van der; Visser, Eric J.W. ; Kroon, Hans de; Eekeren, Nick van - \ 2019
    AIMS Agriculture and Food 4 (2019)3. - ISSN 2471-2086 - p. 547 - 567.
    Agrobiodiversity - Lolium multiflorum - Lolium perenne - Regenerative agriculture - Trifolium pratense - Trifolium repens

    Grass-clover mixtures show many benefits for sustainable agriculture. In the Netherlands, organic farmers often work together in a so-called partner farm concept, with the aim to close nutrient cycles on a regional level. In this system, arable farms grow one-year grass-clover leys, as fodder for a livestock farm, in exchange for, e.g., manure. This practice could also be used in the transition of conventional farms towards a more circular regenerative and nature inclusive agriculture. In the current experiment we assessed the effect of a range of grass (Lolium perenne: Lp, Lolium multiflorum: Lm) and clover (Trifolium pratense: Tp and Trifolium repens: Tr) monocultures and mixtures on both below- and aboveground parameters in light of benefits for livestock and arable farms, and biodiversity. The grass monocultures showed good weed suppression, high root density, and especially Lp had a positive effect on soil structure. Clover, on the other hand, showed high herbage dry matter yield (particularly Tp) and Nitrogen (N) yield, and Tr showed high digestibility. Moreover, clover had a positive effect on the soil mineral N, and earthworm abundance tended to be higher in the clover monocultures. When (some of) the four species were combined in grass-clover mixtures, they combined the positive effects of the species and often even outperformed the (best) monocultures. We concluded that grass-clover mixtures increased agro-ecological functions.

    Effecten van onderwaterdrainage op de regionale watervraag : berekeningen met het Landelijk Hydrologisch Model
    Rozemeijer, Joachim ; Boomsma, Huite ; Veldhuizen, Ab ; Pouwels, Janneke ; Akker, Jan van den; Kroon, Timo - \ 2019
    Delft : Deltares - 66
    In het veenweidegebied is het verminderen van maaivelddaling een belangrijk thema.Onderwaterdrainage wordt gezien als een mogelijkheid om de laagste grondwaterstanden te verhogen en is daarmee eenvan de mogelijkheden om maaivelddaling te verminderen. Het doel van dit onderzoek was de verandering in de watervraag in droge perioden door onderwaterdrainage voor een deel van West-Nederlandin beeld te brengen. Er is gebruik gemaakt vanhet Landelijk Hydrologisch Model (LHM-versie3.4.0) voor het doorrekenen van scenario’s (1) met en zonder onderwaterdrainage, (2) met huidig en toekomstig klimaat (GL en WH) en (3) meten zonder dynamisch peilbeheer.Dein het modelgebruikte drainage-en infiltratiedoorlatendheden zijn ingeschat op basis van meetresultaten uit lokalepilots. Om de effecten van onderwaterdrainage duidelijk te maken focussen we op de verandering in de watervraag voor peilhandhaving in peilvakken die voor minimaal 10% geschikt zijn voor onderwaterdrainage. De resultaten laten zien dat dezewatervraag in een droge periode toeneemt met ongeveer 0.09 mm/dag. De totale watervraag voor peilhandhaving voor deze gebieden is 1.16 mm/dag in dereferentiesituatie, waarmee de relatieve toename uitkomt op ca. 8%. De watervraag voor het gehele beheergebied van de West-Nederlandse waterschappen is 0.66 mm/dag. De extra watervraag voor peilhandhaving door onderwaterdrainage voor het gehele gebied is dan ook ongeveer 0.03 mm/dag (ca. 4%). Bij deze berekening is uitgegaan van een gemiddeld effect van 5-10 cm verhoging van de laagste grondwaterstanden die voorkomt uitpraktijkpilots. Als de infiltratie-effectiviteit van onderwaterdrainage vergroot wordt,bijvoorbeeld door verbeterde aanleg of door pompgestuurde onderwaterdrainage (drukdrains),dan zalhet effect op de laagste grondwaterstanden ende watervraag toenemen. Bij een gemiddelde verhoging van de laagste grondwaterstanden van30-40 cmverwachten we een extra watervraag van ongeveer 0.4 mm/dag (ca. 36%). Voor de gehele West-Nederlandse waterschappen komt dit neer op een extra watervraag van ongeveer 0.11 mm/dag (ca. 18%).De resultaten uit het model moeten gezien worden als een indicatieve kwantificering van de effecten van onderwaterdrainage. Er is behoefte aan meer meetinformatie over de effecten van onderwaterdrainage over langere perioden en in droge jaren en over de effecten op waterfluxen en waterkwaliteit. Deze meetinformatie kan gebruikt worden om ook de effecten op groter schaalniveau beter te kwantificeren.
    Hydrophobic eutectic mixtures as volatile fatty acid extractants
    Bruinhorst, Adriaan van den; Raes, Sanne ; Maesara, Sausan Atika ; Kroon, Maaike C. ; Esteves, A.C.C. ; Meuldijk, Jan - \ 2019
    Separation and Purification Technology 216 (2019). - ISSN 1383-5866 - p. 147 - 157.
    Deep eutectic solvents - Designer solvents - Eutectic mixtures - Liquid–liquid extraction - Volatile fatty acid recovery

    Organic waste streams can be converted into volatile fatty acids (VFAs) via fermentation. VFAs can be used as intermediates in the synthesis of added-value chemicals. In this work, hydrophobic eutectic mixtures were designed for the liquid-liquid extraction of VFAs from dilute aqueous solutions. The eutectic behaviour was screened for over 100 combinations of 16 hydrophobic components that were selected based on a set of predetermined criteria. Mixtures of dihexylthiourea and trioctylphosphine oxide (TOPO) showed the best extraction performance and were stable over a wide pH range. The extraction efficiency increased with increasing hydrophobicity of the VFAs, and only undissociated acids were extracted. Upon increasing the TOPO content of the eutectic mixture, the extraction performance could be improved, confirming the tuneable nature of eutectic solvents. However, the extraction performance was less than that for solutions of TOPO in hydrophobic solvents, even though mole fractions of TOPO were higher in the eutectic mixtures. It was hypothesized that the intermolecular VFA–TOPO interactions required for extraction are suppressed by the inter-component interactions in the eutectic mixture. The inter-component interactions are responsible for the negative deviation from ideality of the melting temperature depressions that extend the liquid window of the mixtures towards the extraction temperature. Hence, the design of novel hydrophobic extractants based on eutectic mixtures was demonstrated. Their performance might be improved by selecting counterparts that interfere less with the interactions required for VFA extraction.

    The Future of Complementarity : Disentangling Causes from Consequences
    Barry, Kathryn E. ; Mommer, Liesje ; Ruijven, Jasper van; Wirth, Christian ; Wright, Alexandra J. ; Bai, Yongfei ; Connolly, John ; Deyn, Gerlinde B. De; Kroon, Hans de; Isbell, Forest ; Milcu, Alexandru ; Roscher, Christiane ; Scherer-Lorenzen, Michael ; Schmid, Bernhard ; Weigelt, Alexandra - \ 2019
    Trends in Ecology and Evolution 34 (2019)2. - ISSN 0169-5347 - p. 167 - 180.
    Abiotic facilitation - Biodiversity - Biotic feedbacks - Complementarity - Complementarity effect - Ecosystem functioning - Plant-soil feedback - Resource partitioning - Resource tracers - Stress amelioration

    Evidence suggests that biodiversity supports ecosystem functioning. Yet, the mechanisms driving this relationship remain unclear. Complementarity is one common explanation for these positive biodiversity–ecosystem functioning relationships. Yet, complementarity is often indirectly quantified as overperformance in mixture relative to monoculture (e.g., ‘complementarity effect’). This overperformance is then attributed to the intuitive idea of complementarity or, more specifically, to species resource partitioning. Locally, however, several unassociated causes may drive this overperformance. Here, we differentiate complementarity into three types of species differences that may cause enhanced ecosystem functioning in more diverse ecosystems: (i) resource partitioning, (ii) abiotic facilitation, and (iii) biotic feedbacks. We argue that disentangling these three causes is crucial for predicting the response of ecosystems to future biodiversity loss.

    The relationship of habitual diet with esophageal inflammation and integrity in eosinophilic esophagitis
    Kroon, Marlou L.A. de; Warners, Marijn J. ; Ampting, Marleen T.J. van; Harthoorn, Lucien F. ; Bredenoord, Arjan J. ; Doorn, Mylene van; Kok, Melanie ; Rhijn, Bram D. van; Eussen, Simone R.B.M. ; Vlieg-Boerstra, Berber J. - \ 2019
    Allergy 74 (2019)5. - ISSN 0105-4538 - p. 1005 - 1009.
    adults - eosinophilic esophagitis - esophageal mucosal integrity - habitual dietary intake - inflammation
    Hatching failure and accumulation of organic pollutants through the terrestrial food web of a declining songbird in Western Europe
    Oosten, H.H. van; Burg, Arnold B. van den; Arlt, Debora ; Both, Christiaan ; Brink, Nico W. van den; Chiu, Suzanne ; Crump, Doug ; Jeppsson, Tobias ; Kroon, Hans de; Traag, Wim ; Siepel, Henk - \ 2019
    Science of the Total Environment 650 (2019). - ISSN 0048-9697 - p. 1547 - 1553.
    Dioxin - DLC - Embryo - Inbreeding - Malformation - Passerine

    Population growth in passerine birds is largely driven by fecundity. If fecundity is affected, for instance by hatching failure, populations may decline. We noted high hatching failure of up to 27% per year in relict populations of the Northern wheatear (Oenanthe oenanthe) in The Netherlands, a strongly declining, migratory passerine in Europe. This hatching failure itself can cause population decline, irrespective of other adverse factors. Additionally, we investigated the cause of hatching failure. Unhatched eggs showed egg yolk infections or embryonic malformations, part of which is associated with the actions of dioxin-like compounds (DLCs). Indeed, DLCs appear to bioaccumulate in the local foodweb, where the soil contained only background concentrations, similar to those found at many other locations. DLC concentrations in Dutch eggs were six-fold higher than those in a reference population in Sweden, where egg failure was only 6%. However, Northern wheatears appear to be only moderately sensitive to the actions of DLCs, because of their specific Ah-receptor type which may moderate the receptor mediated effects of DLCs. This indicates that the concentrations of DLCs, although elevated, may not have caused the embryo malformations or the low hatching rates. We discuss whether other toxins may be important or imbalances in the nutrition and if inbreeding may play a larger role than expected.

    Plant species richness and functional groups have different effects on soil water content in a decade-long grassland experiment
    Fischer, Christine ; Leimer, Sophia ; Roscher, Christiane ; Ravenek, Janneke ; Kroon, Hans de; Kreutziger, Yvonne ; Baade, Jussi ; Beßler, Holger ; Eisenhauer, Nico ; Weigelt, Alexandra ; Mommer, Liesje ; Lange, Markus ; Gleixner, Gerd ; Wilcke, Wolfgang ; Schröder, Boris ; Hildebrandt, Anke - \ 2019
    Journal of Ecology 107 (2019)1. - ISSN 0022-0477 - p. 127 - 141.
    biodiversity - functional groups - Jena Experiment - plant–soil–water relation - soil water content - spatial–temporal variability - species richness

    The temporal and spatial dynamics of soil water are closely interlinked with terrestrial ecosystems functioning. The interaction between plant community properties such as species composition and richness and soil water mirrors fundamental ecological processes determining above-ground–below-ground feedbacks. Plant–water relations and water stress have attracted considerable attention in biodiversity experiments. Yet, although soil scientific research suggests an influence of ecosystem productivity on soil hydraulic properties, temporal changes of the soil water content and soil hydraulic properties remain largely understudied in biodiversity experiments. Thus, insights on how plant diversity—productivity relationships affect soil water are lacking. Here, we determine which factors related to plant community composition (species and functional group richness, presence of plant functional groups) and soil (organic carbon concentration) affect soil water in a long-term grassland biodiversity experiment (The Jena Experiment). Both plant species richness and the presence of particular functional groups affected soil water content, while functional group richness played no role. The effect of species richness changed from positive to negative and expanded to deeper soil with time. Shortly after establishment, increased topsoil water content was related to higher leaf area index in species-rich plots, which enhanced shading. In later years, higher species richness increased topsoil organic carbon, likely improving soil aggregation. Improved aggregation, in turn, dried topsoils in species-rich plots due to faster drainage of rainwater. Functional groups affected soil water distribution, likely due to plant traits affecting root water uptake depths, shading, or water-use efficiency. For instance, topsoils in plots containing grasses were generally drier, while plots with legumes were moister. Synthesis. Our decade-long experiment reveals that the maturation of grasslands changes the effects of plant richness from influencing soil water content through shading effects to altering soil physical characteristics in addition to modification of water uptake depth. Functional groups affected the soil water distribution by characteristic shifts of root water uptake depth, but did not enhance exploitation of the overall soil water storage. Our results reconcile previous seemingly contradictory results on the relation between grassland species diversity and soil moisture and highlight the role of vegetation composition for soil processes.

    Aankoop voer belangrijkste kostenpost in VS
    Haan, M.H.A. de; Evers, A.G. - \ 2018
    Verantwoorde veehouderij
    Maandelijks wordt een vergelijking gemaakt tussen de Nederlandse melkveehouderij en een aantal andere exporterende zuivellanden landen via een specifiek kengetal. Deze keer ligt de focus op het aandeel voergebonden kosten ten opzichte van de totale kosten. De Vereningde Staten spant de kroon. Van de totale kosten is daar bijna 70 procent gerelateerd aan de aankoop van voer.
    Diversiteit en krielonderzoek : bij de traditionele Nederlandse hoenderrassen
    Bortoluzzi, C. ; Megens, H.J.W.C. ; Crooijmans, R.P.M.A. ; Boer, Henk de; Taks, A. ; Kroon, Piet ; Hoving, A.H. - \ 2018
    Kleindier magazine 132 (2018)6. - p. 11 - 13.
    Recent onderzoek heeft aangetoond dat de ‘nieuwe’ krielrassen, de verkrielde vorm van de grote hoenderrassen,genetische variatie toevoegt aan de Nederlandse hoenderrassen en oorspronkelijke krielrassen. Door het kruisenmet dieren van verschillende rassen van niet-Nederlandseoorsprong worden nieuwe kenmerken vastgelegd enworden nieuwe rassen gevormd met een andere genetische diversiteit. Binnen de rassen is deze diversiteit laag,vanwege intensieve selectie op specifieke eigenschappenen door paringen tussen verwante dieren. Dit vergroot dekans op erfelijke aandoeningen en minder vitaal nageslacht. Volgend op dit onderzoek starten Wageningen University en Research, Animal Breeding en Genomics en Centrum voor Genetische Bronnen Nederland samen met de speciaalclubs een pilot om per paring informatie vannakomelingen te verzamelen. Deze informatie zal worden gebruikt om verstandig fokken voor de toekomst beter mogelijk te maken. Voor dit pilotonderzoek zijn vier rassen gekozen: de Eikenburger kriel, een ras met veel inteelt,de Nederlandse Uilebaard, een ras met lage inteelt en het Twents hoen en de Lakenvelder, die genetisch gezien op afstand staan van de andere Nederlandse rassen.
    Diversiteit en krielonderzoek bij de traditionele Nederlandse hoenderrassen
    Bortoluzzi, C. ; Megens, H.J.W.C. ; Crooijmans, R.P.M.A. ; Boer, Henk de; Taks, A. ; Kroon, P. ; Hoving, A.H. - \ 2018
    Zeldzaam huisdier 43 (2018)3. - ISSN 0929-905X - p. 20 - 21.
    Fokken van de verkrielde vorm van de grote hoenderrassen voegt genetische variatie toe aan het geheel van de Nederlandse hoender-rassen. Dat blijkt uit recent onderzoek. Maar binnen die rassen is de diversiteit laag door selectie op specifieke eigenschappen en parin-gen tussen verwante dieren.
    Wolf wacht bed van regels
    Jansman, H.A.H. - \ 2018

    Provincies werken aan een herziene versie van het 'draaiboek wolf', nu het roofdier bijna 150 jaar nadat het dier in nederland was uitgeroeid terug is. In Friesland, Groningen, Overijssel, Gelderland en Limburg zijn de afgelopen maanden meerdere wolven gesignaleerd. Maar Drenthe spant de kroon. Alleen al in maart en april zijn er negen wolven gezien, waarvan zeker twee verschillende wolven schapen hebben aangevallen.

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