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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Cadmium, lead, mercury and arsenic in animal feed and feed materials – trend analysis of monitoring results
Adamse, Paulien ; Fels, Ine van der; Jong, Jacob de - \ 2017
Food Additives & Contaminants. Pt. A, Chemistry, Analysis, Control, Exposure & Risk Assessment 34 (2017)8. - ISSN 1944-0049 - p. 1298 - 1311.
arsenic - cadmium - chemical contaminant - element - feed material - Heavy metals - lead - mercury - monitoring programme - trends

This study aimed to obtain insights into the presence of cadmium, lead, mercury and arsenic in feed materials and feed over time for the purpose of guiding national monitoring. Data from the Dutch feed monitoring programme and from representatives of the feed industry during the period 2007–13 were used. Data covered a variety of feed materials and compound feeds in the Netherlands. Trends in the percentage of samples that exceeded the maximum limit (ML) set by the European Commission, and trends in average, median and 90th percentile concentrations of each of these elements were investigated. Based on the results, monitoring should focus on feed material of mineral origin, feed material of marine origin, especially fish meal, seaweed and algae, as well as feed additives belonging to the functional groups of (1) trace elements (notably cupric sulphate, zinc oxide and manganese oxide for arsenic) and (2) binders and anti-caking agents. Mycotoxin binders are a new group of feed additives that also need attention. For complementary feed it is important to make a proper distinction between mineral and non-mineral feed (lower ML). Forage crops in general do not need high priority in monitoring programmes, although for arsenic grass meal still needs attention.

Ontwikkelingen in Foodservice : online en beleving creëren nieuwe kansen voor toeleveranciers van agf
Splinter, G.M. ; Haaster-de Winter, M.A. van - \ 2015
Wageningen : LEI Wageningen UR - 30 p.
commerciële catering - food service management - groenten - fruit - gemaksvoedsel - voedselconsumptie - elektronische handel - consumentenvoorkeuren - tendensen - commercial food service - vegetables - convenience foods - food consumption - electronic commerce - consumer preferences - trends
Het voedsellandschap is in beweging. Een ontwikkeling met grote gevolgen voor “vers” en haar toeleveranciers. Voedsel is op steeds meer (verschillende) plaatsen te koop en wordt aangeboden door verschillende aanbieders. GroentenFruit Huis wil de groenten- en fruitsector versterken en de positie van bedrijven verbeteren. LEI Wageningen UR heeft daarom twee ontwikkelingen in de Foodservicemarkt onderzocht: online en beleving. Twee aspecten die het niveau van een individueel bedrijf overstijgen en impact hebben op de bestaande structuur. De uitkomsten zijn aangevuld met informatie over nieuwe ontwikkelingen binnen het thema “gemak”. Hoe moeten de ontwikkelingen worden gezien en wat is het effect ervan op de toeleveranciers van groenten en fruit? En op hun product(en)?
Strong recovery of dragonflies in recent decades in The Netherlands
Termaat, T. ; Grunsven, R.H.A. van; Plate, C.L. ; Strien, A. van - \ 2015
Freshwater Science 34 (2015)3. - ISSN 2161-9549 - p. 1094 - 1104.
change odonata corduliidae - boreal forest lakes - climate-change - trends - conservation - assemblages - indicators - integrity - abundance - plants
Many dragonfly species in The Netherlands declined in the 20th century because of acidification, eutrophication, and desiccation of lotic and lentic habitats and canalization of streams and rivers. These pressures peaked in the 1970s, when 26 of 65 native species had an unfavorable conservation status on the 1997 Dutch Red List. Since the 1980s, environmental regulations have led to improved water quality, and any habitat restoration projects have been carried out. We used standardized monitoring data (1999–2013) and unstandardized observations (1991–2013) to investigate how dragonflies have changed in the last 20 y on a national scale. We compared trends of dragonfly species from different habitat types and with southern vs northern distribution in Europe. Dragonflies recovered strongly in The Netherlands in a period of ~20 y, probably because of recent habitat improvements. Lotic species have benefitted more than lentic species, and southern species have more positive trends than northern species, suggesting that climate change has contributed to the recovery. Dragonflies were resilient and able to quickly recover when their habitats were restored. Recovery has led to a better conservation status for many species. Unstandardized data delivered results consistent with those from monitoring data and had greater statistical power to detect trends because many more unstandardized data than standardized data were available. Thus, when the goal is to provide a general overview of changes in dragonflies, unstandardized data can outperform standardized abundance data. However, abundance data may deliver complementary information for individual species. Our results support the suitability of dragonflies as indicators of freshwater habitat condition, but they recover more strongly in The Netherlands than many other insects, possibly because of their higher dispersal abilities or different habitat requirements.
Sociale dynamiek in Het Nieuwe Telen : Aangrijpingspunten voor opschaling naar 2000 ha in 2020
Buurma, J.S. ; Beers, P.J. ; Smit, P.X. - \ 2015
Wageningen : LEI Wageningen UR (Report / LEI 2015-051) - ISBN 9789086157136 - 54
glastuinbouw - ondernemerschap - teeltsystemen - duurzame landbouw - doelstellingen - kennisoverdracht - energiebesparing - klimaatregeling - samenleving - tendensen - besluitvorming - sociale factoren - nederland - greenhouse horticulture - entrepreneurship - cropping systems - sustainable agriculture - objectives - knowledge transfer - energy saving - air conditioning - society - trends - decision making - social factors - netherlands
De huidige studie richt zich op de sociale dynamiek in de kopgroep van de brede praktijk: welke sociale processen vinden daar plaats? Met het verkregen inzicht probeert KaE een versnelling in de introductie van HNT te bewerkstelligen, en daarmee de taakstelling van 2.000 ha HNT in 2020 haalbaar te maken. Voor versnelling van de introductie van Het Nieuwe Telen (HNT), een nieuwe en energiebesparende benadering voor klimaatsturing in de glastuinbouw, kan het beste worden samengewerkt met de zogenoemde ‘gewasgerichte ondernemers’. Deze ondernemers zijn te herkennen aan hun passie voor klimaatsturing, hun voorkeur om te leren met collega’s en hun behoefte om plantgezondheid te borgen. Een extra argument is dat de gewasgerichte ondernemers binnen de glastuinbouw verreweg de grootste deelgroep (circa 50% van populatie met circa 60% van het areaal) vormen. Naast de gewasgerichte ondernemers bestaan marktgerichte en kostengerichte ondernemers. Deze deelgroepen redeneren vanuit andere bedrijfsomstandigheden en andere prioriteiten (Tabel S.1). Zij vergen een eigen benadering bij de introductie van HNT. De marktgerichte ondernemers proberen de maatschappelijke meerwaarde van HNT in de markt te verzilveren. Daar kan de glastuinbouw van leren. De kostengerichte ondernemers wachten op een blauwdruk voor HNT. Zij kunnen leren van de voortschrijdende HNT-inzichten van de gewasgerichte ondernemers.
Impact of nitrogen deposition on larval habitats: the case of the Wall Brown butterfly Lasiommata megera
Klop, E. ; Omon, B. ; Wallis de Vries, M.F. - \ 2015
Journal of Insect Conservation 19 (2015)2. - ISSN 1366-638X - p. 393 - 402.
british butterflies - herbivorous insects - pararge-aegeria - limitation - climate - biodiversity - adaptation - phosphorus - landscape - trends
Nitrogen deposition is considered as one of the main threats to biodiversity and ecosystem functioning. Three mechanisms have been proposed to explain the detrimental effect of excess nitrogen on butterflies: loss of host plants, deterioration of food plant quality and microclimatic cooling in spring. Here, we investigated whether these mechanisms might explain the dramatic recent decline of the Wall Brown butterfly Lasiommata megera. Monitoring data from the Netherlands indeed show a greater decline at higher critical load exceedance of nitrogen deposition. Loss of host plants is not a likely explanation of the decline for this grass-feeding species. In a greenhouse experiment, we only found beneficial effects of nitrogen fertilization on larval performance, which seems to rule out a nutritional cause; application of a drought treatment did not result in significant effects. Microclimatic conditions at overwintering larval sites of L. megera and the related but increasing Pararge aegeria provided a possible clue. In comparison with larval sites of P. aegeria, those of L. megera showed higher temperatures at the mesoscale and less plant cover and more dead plant material at the microscale. L. megera caterpillars were also found closer to the shelter of vertical structures. The greater dependence on warm microclimates suggests that microclimatic cooling through excess nitrogen contributes to the recent decline of L. megera.
Potential of extensification of European agriculture for a more sustainable food system; the case for nitrogen and livestock
Grinsven, J.J.M. van; Erisman, J.W. ; Vries, W. de; Westhoek, H. - \ 2015
Environmental Research Letters 10 (2015)2. - ISSN 1748-9326 - 10 p.
dairy farms - management - intensification - welfare - trends - impact - costs - meat - pig
Most global strategies for future food security focus on sustainable intensification of production of food and involve increased use of nitrogen fertilizer and manure. The external costs of current high nitrogen (N) losses from agriculture in the European Union, are 0.3–1.9% of gross domestic product (GDP) in 2008. We explore the potential of sustainable extensification for agriculture in the EU and The Netherlands by analysing cases and scenario studies focusing on reducing N inputs and livestock densities. Benefits of extensification are higher local biodiversity and less environmental pollution and therefore less external costs for society. Extensification also has risks such as a reduction of yields and therewith a decrease of the GDP and farm income and a smaller contribution to the global food production, and potentially an i0ncrease of global demand for land. We demonstrate favourable examples of extensification. Reducing the N fertilization rate for winter wheat in Northwest Europe to 25–30% below current N recommendations accounts for the external N cost, but requires action to compensate for a reduction in crop yield by 10–20%. Dutch dairy and pig farmers changing to less intensive production maintain or even improve farm income by price premiums on their products, and/or by savings on external inputs. A scenario reducing the Dutch pig and poultry sector by 50%, the dairy sector by 20% and synthetic N fertilizer use by 40% lowers annual N pollution costs by 0.2–2.2 billion euro (40%). This benefit compensates for the loss of GDP in the primary sector but not in the supply and processing chain. A 2030 scenario for the EU27 reducing consumption and production of animal products by 50% (demitarean diet) reduces N pollution by 10% and benefits human health. This diet allows the EU27 to become a food exporter, while reducing land demand outside Europe in 2030 by more than 100 million hectares (2%), which more than compensates increased land demand when changing to organic farming. We conclude that in Europe extensification of agriculture is sustainable when combined with adjusted diets and externalization of environmental costs to food prices.
De Nederlandse visverwerkende industrie en visgroothandel : economische analyse van de sector, ontwikkelingen en trends
Beukers, R. - \ 2015
Den Haag : LEI Wageningen UR (Report LEI 2014-026) - ISBN 9789086157099 - 87
visverwerkende industrie - handel - vis - economische analyse - tendensen - werkgelegenheid - omzet - import - export - fish industry - trade - fish - economic analysis - trends - employment - turnover - imports - exports
Dit onderzoek geeft inzicht in de economische situatie van de visverwerkende industrie en visgroothandel in Nederland door een analyse van de economische structuur van de sector en de belangrijkste ontwikkelingen. De bedrijven in de visverwerkende industrie en visgroothandel hadden in 2013 een gezamenlijke omzet van 3.6 miljard euro; een groei van 7% ten opzichte van de omzet in 2009. 70% van de totale omzet van Nederlandse visverwerkende bedrijven en visgroothandels werd behaald uit export; 30% werd gerealiseerd op de binnenlandse markt.
Detecting clear-cuts and decreases in forest vitality using MODIS NDVI time series
Lambert, J. ; Denux, J.P. ; Verbesselt, J. ; Balent, G. ; Cheret, V. - \ 2015
Remote Sensing 7 (2015)4. - ISSN 2072-4292 - p. 3588 - 3612.
coarse spatial-resolution - vegetation indexes - climate-change - landsat imagery - boreal forest - cover - trends - avhrr - disturbance - drought
This paper examines the potential of MODIS-NDVI time series for detecting clear-cuts in a coniferous forest stand in the south of France. The proposed approach forms part of a survey monitoring the status of forest health and evaluating the forest decline phenomena observed over the last few decades. One of the prerequisites for this survey was that a rapid and easily reproducible method had to be developed that differentiates between forest clear-cuts and changes in forest health induced by environmental factors such as summer droughts. The proposed approach is based on analysis of the breakpoints detected within NDVI time series, using the “Break for Additive Seasonal and Trend” (BFAST) algorithm. To overcome difficulties detecting small areas on the study site, we chose a probabilistic approach based on the use of a conditional inference tree. For model calibration, clear-cut reference data were produced at MODIS resolution (250 m). According to the magnitude of the detected breakpoints, probability classes for the presence of clear-cuts were defined, from greater than 90% to less than 3% probability of a clear-cut. One of the advantages of the probabilistic model is that it allows end users to choose an acceptable level of uncertainty depending on the application. In addition, the use of BFAST allows events to be dated, thus making it possible to perform a retrospective analysis of decreases in forest vitality in the study area.
Ruimte voor de toekomst in het landelijk gebied : trendverkenning 2020-2030 voor gemeenten met veel landelijk gebied /
Nieuwenhuizen, W. ; Gies, T.J.A. ; Och, R.A.F. van; Rooij, L.L. de - \ 2015
Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2628) - 81
plattelandsomgeving - tendensen - gemeenten - platteland - plattelandsontwikkeling - landbouw - demografie - werkgelegenheid - recreatie op het platteland - rural environment - trends - municipalities - rural areas - rural development - agriculture - demography - employment - rural recreation
Hoe het landelijk gebied er in 2040 uit zal zien, weet niemand. Toch is een aantal trends aan te wijzen dat nu al zichtbaar is en voor een groot deel de richting zal bepalen waarin het zich gaat ontwikkelen. Het landelijk gebied wordt steeds meer een multifunctionele leef- en werkomgeving, waarbinnen initiatieven van burgers en bedrijven oplossingen aandragen voor lokale problemen. Schaalvergroting van (agrarische) bedrijven en voorzieningen gaat gelijk op met een toename van kleinschalige en lokale initiatieven van burgers en bedrijven. Technologische innovatie kan de bedrijvigheid en de leefbaarheid in het landelijk gebied vergroten. Tot slot is een toename van extreme gebeurtenissen mogelijk door klimaatverandering of de uitbraak van dierziekten. Dit rapport beschrijft een aantal van de belangrijkste trends voor gemeenten met veel landelijk gebied. De trends worden besproken aan de hand van verschillende thema's.
Establishing Guidelines to Retain Viability of Probiotics during Spray Drying
Perdana, J.A. ; Fox, M.B. ; Boom, R.M. ; Schutyser, M.A.I. - \ 2015
Drying Technology 33 (2015)13. - ISSN 0737-3937 - p. 1560 - 1569.
lactobacillus-plantarum wcfs1 - inactivation - integration - isotherms - products - sorption - storage - trends - foods - model
We present the application of a model-based approach to map processing conditions suitable to spray dry probiotics with minimal viability loss. The approach combines the drying history and bacterial inactivation kinetics to predict the retention of viability after drying. The approach was used to systematically assess the influence of operational co-current spray drying conditions on residual viability. Moreover, two promising alternative drying strategies for probiotics were evaluated involving encapsulation in a hollow particle and using an ‘ideal-mixed’ dryer system. Finally, a graph was constructed with the model to provide visual guidelines to optimize spray dying for probiotics in terms of viability and drying efficiency.
Foodtopia : het voedsel van de toekomst
Govers, F. ; Boekel, T. van; Buiter, R. - \ 2015
Den Haag : Stichting Biowetenschappen en Maatschappij (Cahier / Bio-Wetenschappen en Maatschappij 34e jrg. (2015), 1) - ISBN 9789073196773 - 63
voedselproductie - voeding en gezondheid - innovaties - vleesvervangers - voedseltechnologie - duurzaamheid (sustainability) - toekomst - voedselconsumptie - insecten als voedsel - vleeswaren - kunstvlees - tendensen - consumenten - food production - nutrition and health - innovations - meat alternates - food technology - sustainability - future - food consumption - insects as food - meat products - meat analogues - trends - consumers
Van gekookte en luchtdicht verpakte producten tot sterk geconcentreerde voedingsmiddelen; in de afgelopen eeuwen hebben diverse innovaties ons voedsel veiliger, langer houdbaar en beter beschikbaar gemaakt. Maar ook al lijkt het voedsel in de westerse wereld nu overvloedig en gevarieerd voor handen, er is nog steeds behoefte aan innovaties. Als we over een halve eeuw negen miljard monden willen voeden zal onze voedselvoorziening bijvoorbeeld veel duurzamer moeten worden. Eiwitten zullen vaker in de vorm van kweekvlees, insecten of – al dan niet omgebouwde – plantaardige eiwitten worden gegeten dan in de vorm van een klassieke biefstuk. En wat wordt de rol van voeding in onze gezondheid? Gaan we onze conditie oppeppen met innovatieve ‘superfoods’ op basis van gojibessen en tarwegras, of moeten we op dat gebied vooral níet innoveren en terug naar het klassieke advies van twee ons groente en twee stuks fruit? In dit cahier worden wetenschappers van naam op het gebied van voedselinnovaties geinterviewd. Het cahier sluit aan bij de tentoonstelling Foodtopia die in 2015 te zien is in Museum Boerhaave in Leiden.
Impact of predicted changes in rainfall and atmospheric carbon dioxide on maize and wheat yeilds in the Central Rift Valley of Ethiopia
Muluneh, A. ; Biazin, B. ; Stroosnijder, L. ; Bewket, W. ; Keesstra, S.D. - \ 2015
Regional Environmental Change 15 (2015)6. - ISSN 1436-3798 - p. 1105 - 1119.
fao crop model - climate-change - risk-assessment - aquacrop model - rainy-season - east-africa - dry spell - variability - drought - trends
This study assesses potential impacts of climate change on maize and wheat yields in the Central Rift Valley (CRV) of Ethiopia. We considered effects of elevated atmospheric carbon dioxide (CO2) and changes in rainfall during the main (Kiremt) and the short (Belg) rainfall cropping seasons during the two future periods (2020–2049 and 2066–2095). The MarkSimGCM daily weather generator was used to generate projected rainfall and temperature data using the outputs from ECHAM5 general circulation model and ensemble mean of six models under A2 (high) and B1 (low) emission scenarios. Crop yield simulations were made with the FAO’s AquaCrop model. The projected rainfall during Kiremt increases by 12–69 % while rainfall during Belg decreases by 20–68 %. The combined effect of elevated CO2 and projected climate factors increases maize yield by up to 59 % in sub-humid/humid areas of the CRV, but could result in a decrease of up to 46 % in the semiarid areas under ECHAM5 model. However, the maize yield increases in all parts of the CRV under the ensemble mean of models. Wheat yield shows no significant response to the projected rainfall changes, but increases by up to 40 % due to elevated CO2. Our results generally suggest that climate change will increase crop yields in the sub-humid/humid regions of the CRV. However, in the semi-arid parts the overall projected climate change will affect crop yields negatively.
Relationships between soil fertility, herbage quality and manure composition on grassland-based dairy farms
Reijneveld, J.A. ; Abbink, G.W. ; Termorshuizen, A.J. ; Oenema, O. - \ 2014
European Journal of Agronomy 56 (2014). - ISSN 1161-0301 - p. 9 - 18.
new-zealand - agricultural land - phosphorus status - central-europe - new-york - yield - management - magnesium - trends - fertilization
It is reasonable to expect that compliance with grassland fertilization recommendations in the long run results in optimal soil fertility, and subsequent herbage quality. Here, we evaluate the development of soil, herbage and manure characteristics and their relation over the last decades. We hypothesized that herbage and manure quality are related with soil fertility. We used a large database with results of soil tests, spring forage quality characteristics, and manure analyses, which were made on demand of dairy farmers. We considered the Netherlands as a whole and three selected regions with contrasting soil types (sandy soil, riverine clay, and peaty marine clay). Effects of soil fertility on herbage quality were evident when comparing farms. Farms higher in soil P and K generally have correspondingly higher contents in forage. On average, soil fertility and herbage characteristics were within or just above the agronomical optimal range during the last decades. Herbage crude protein content decreased in all regions during last two decades, which is likely an effect of legislative measures on decreasing the application of N. Selenium (Se) and sulphur (S) contents increased sharply on sandy soils, likely because of increased use of Se and S containing fertilizers. Manure composition did not differ between soil types. In conclusion, at farm level, the element composition of herbage reflected the soil fertility status. The contents of S, P, K, Na, Mg, and Ca in the herbage were all significantly influenced by soil fertility characteristics. Our results emphasize the importance of maintaining soil fertility for high quality roughage production. (C) 2014 Elsevier B.V. All rights reserved.
Characterization of OMI tropospheric NO2 over the Baltic Sea region
Ialongo, I. ; Hakkarainen, J. ; Hyttinen, N. ; Jalkanen, J.P. ; Johansson, L. ; Boersma, K.F. ; Krotkov, N. ; Tamminen, J. - \ 2014
Atmospheric Chemistry and Physics 14 (2014)15. - ISSN 1680-7316 - p. 7795 - 7805.
ozone monitoring instrument - nitrogen-oxides - satellite-observations - retrieval algorithm - exhaust emissions - trends - urban - model
Satellite-based data are very important for air-quality applications in the Baltic Sea region, because they provide information on air pollution over the sea and where ground-based and aircraft measurements are not available. Both the emissions from urban sites over land and ships over sea, contribute to tropospheric NO2 levels. Tropospheric NO2 monitoring at high latitudes using satellite data is challenging because of the reduced light hours in winter and the weak signal due to the low Sun, which make the retrieval complex. This work presents a characterization of tropospheric NO2 columns based on case-study analysis in the Baltic Sea region, using the Ozone Monitoring Instrument (OMI) tropospheric NO2 standard product. Previous works have focused on larger seas and lower latitudes. The results of this paper showed that, despite the regional area of interest, it is possible to distinguish the signal from the main coastal cities and from the ships by averaging the data over a seasonal time range. The summertime NO2 emission and lifetime values (E' = (1.5 +/- 0.6) mol s(-1) and tau = (3 +/- 1) h, respectively) in Helsinki were estimated from the decay of the signal with distance from the city center. These results agree within the uncertainties with the emissions from the existing database. For comparison, the results for the cities of Saint Petersburg and Stockholm are also shown. The method developed for megacities was successfully applied to smaller-scale sources, in both size and intensity, which are located at high latitudes (similar to 60 degrees N). The same methodology could be applied to similar-scale cities elsewhere, as long as they are relatively isolated from other sources. Transport by the wind plays an important role in the Baltic Sea region. The NO2 spatial distribution is mainly determined by the contribution of westerly winds, which dominate the wind patterns during summer. The comparison between the ship emissions from model calculations and OMI NO2 tropospheric columns supports the applicability of satellite data for ship emission monitoring. In particular, both the ship emission data and the OMI observations showed similar year-to-year variability, with a drop in the year 2009, corresponding to the effect of the financial crisis.
Island life shapes the physiology and life history of eastern bluebirds (Sialia sialis)
Matson, K.D. ; Mauck, R.A. ; Lynn, S.E. ; Tieleman, B.I. - \ 2014
Physiological and Biochemical Zoology 87 (2014)1. - ISSN 1522-2152 - p. 172 - 182.
body-size - immune-response - birds - populations - conservation - biodiversity - haptoglobin - extinction - trends - growth
Abstract Island organisms face a range of extrinsic threats to their characteristically small populations. Certain biological differences between island and continental organisms have the potential to exacerbate these threats. Understanding how island birds differ from their continental relatives may provide insight into population viability and serve as a predictive tool for conservation efforts. We compared an eastern bluebird population in Ohio with a threatened population in Bermuda in terms of the birds' development, morphology, immunology, and reproduction. These comparisons revealed that island nestlings had shorter wings and island adults had longer wings than their continental analogs. Island nestlings also had shorter tarsi than continental nestlings at day 8 posthatch, but this difference was absent at day 15 and in adults. Adults weighed less in Bermuda than in Ohio, and both nestlings and adults in Bermuda exhibited higher levels of two immunological indexes (concentrations of an acute-phase protein and titers of nonspecific antibodies). Clutch sizes and hatch rates did not differ between the island and continental populations; however, as the breeding season progressed, brood sizes declined in Bermuda, whereas no such decline occurred in Ohio. Despite these differences and differences in nestling development, island and continental parents fed their nestlings at equal rates. Overall, our results suggest that the Bermuda phenotype may be adjusted to certain aspects of the island environment but not to others. Efforts to conserve the bluebirds of Bermuda may be improved by focusing on the intraseasonal patterns in nestling mortality and, more generally, the survival probabilities of different age classes.
Contagious animal diseases: The science behind trade policies and standards (Personal View)
Boqvist, S. ; Dekker, A. ; Depner, K. ; Grace, D. ; Hueston, W. ; Stark, K.D.C. ; Sternberg Lewerin, S. - \ 2014
The Veterinary Journal 202 (2014)1. - ISSN 1090-0233 - p. 7 - 10.
pcr detection methods - swine-fever virus - mouth-disease - ring test - vaccination - transmission - products - drivers - impacts - trends
Changes in wet nitrogen deposition in the United States between 1985 and 2012
Du, E. ; Vries, W. de; Galloway, J.N. ; Hu, X. ; Fang, J. - \ 2014
Environmental Research Letters 9 (2014). - ISSN 1748-9326 - 8 p.
precipitation chemistry - ammonia emissions - reactive nitrogen - reduced nitrogen - critical loads - trends - environment - future - usa
The United States (US) is among the global hotspots of nitrogen (N) deposition and assessing the temporal trends of wet N deposition is relevant to quantify the effectiveness of existing N regulation policies and its consequent environmental effects. This study analyzed changes in observed wet deposition of dissolved inorganic N (DIN = ammonium + nitrate) in the US between 1985 and 2012 by applying a Mann–Kendall test and Regional Kendall test. Current wet DIN deposition (2011–2012) data were used to gain insight in the current pattern of N deposition. Wet DIN deposition generally decreased going from Midwest > Northeast > South > West region with a national mean rate of 3.5 kg N ha-1 yr-1. Ammonium dominated wet DIN deposition in the Midwest, South and West regions, whereas nitrate and ammonium both contributed a half in the Northeast region. Wet DIN deposition showed no significant change at the national scale between 1985 and 2012, but profound changes occurred in its components. Wet ammonium deposition showed a significant increasing trend at national scale (0.013 kg N ha-1 yr-2), with the highest increase in the Midwest and eastern part of the South region. Inversely, wet nitrate deposition decreased significantly at national scale (-0.014 kg N ha-1 yr-2), with the largest reduction in the Northeast region. Overall, ratios of ammonium versus nitrate in wet deposition showed a significant increase in all the four regions, resulting in a transition of the dominant N species from nitrate to ammonium. Distinct magnitudes, trends and patterns of wet ammonium and nitrate deposition suggest the needs to control N emissions by species and regions to avoid negative effects of N deposition on ecosystem health and function in the US.
Strong contribution of autumn phenology to changes in satellite-derived growing season length estimates across Europe (1982–2011)
Garonna, I. ; Jong, R. de; Wit, A.J.W. de; Mücher, C.A. ; Schmid, B. ; Schaepman, M.E. - \ 2014
Global Change Biology 20 (2014)11. - ISSN 1354-1013 - p. 3457 - 3470.
land-surface phenology - high-resolution radiometer - vegetation index ndvi - spring phenology - climate-change - time-series - monitoring vegetation - trends - avhrr - models
Land Surface Phenology (LSP) is the most direct representation of intra-annual dynamics of vegetated land surfaces as observed from satellite imagery. LSP plays a key role in characterizing land-surface fluxes, and is central to accurately parameterizing terrestrial biosphere–atmosphere interactions, as well as climate models. In this article, we present an evaluation of Pan-European LSP and its changes over the past 30 years, using the longest continuous record of Normalized Difference Vegetation Index (NDVI) available to date in combination with a landscape-based aggregation scheme. We used indicators of Start-Of-Season, End-Of-Season and Growing Season Length (SOS, EOS and GSL, respectively) for the period 1982–2011 to test for temporal trends in activity of terrestrial vegetation and their spatial distribution. We aggregated pixels into ecologically representative spatial units using the European Landscape Classification (LANMAP) and assessed the relative contribution of spring and autumn phenology. GSL increased significantly by 18–24 days decade-1 over 18–30% of the land area of Europe, depending on methodology. This trend varied extensively within and between climatic zones and landscape classes. The areas of greatest growing-season lengthening were the Continental and Boreal zones, with hotspots concentrated in southern Fennoscandia, Western Russia and pockets of continental Europe. For the Atlantic and Steppic zones, we found an average shortening of the growing season with hotspots in Western France, the Po valley, and around the Caspian Sea. In many zones, changes in the NDVI-derived end-of-season contributed more to the GSL trend than changes in spring green-up, resulting in asymmetric trends. This underlines the importance of investigating senescence and its underlying processes more closely as a driver of LSP and global change.
Do mother's and father's education condition the impact of parental divorce on child well-being?
Mandemakers, J.J. ; Kalmijn, M. - \ 2014
Social Science Research 44 (2014). - ISSN 0049-089X - p. 187 - 199.
mental-health trajectories - nonresident fathers - marital disruption - family-structure - economic-status - united-states - life-course - trends - resources - instability
We use the British Cohort Study to investigate to what extent parental resources moderate the association between parental divorce in childhood and lowered child well-being as indicated by maternal reports of child psychological well-being and by academic test scores (reading and math tests). We argue that children of mothers with more years of education suffer less when their parents split up because better educated mothers may be better able to provide a safe and stable environment for their children after divorce. In addition, we argue that having a better educated father could either aggravate or reduce the effects of parental divorce. This is one of the first studies to simultaneously investigate the role of maternal, and paternal resources, and pre-divorce shared resources. Our analyses indicate that the effect of parental divorce on psychological well-being is reduced for better educated mothers and for families with more pre-divorce economic resources, but increased for better educated fathers. For academic test scores we find a protective effect of having a better educated father and higher pre-divorce social resources.
No evidence of the effect of extreme weather events on annual occurrence of four groups of ectothermic species
Malinowska, A.H. ; Strien, A.J. van; Verboom, J. ; Wallis de Vries, M.F. ; Opdam, P. - \ 2014
PLoS One 9 (2014)10. - ISSN 1932-6203 - 10 p.
climate-change - metapopulation dynamics - habitat fragmentation - population-dynamics - occupancy models - european climate - range expansion - dispersal - trends - impact
Weather extremes may have strong effects on biodiversity, as known from theoretical and modelling studies. Predicted negative effects of increased weather variation are found only for a few species, mostly plants and birds in empirical studies. Therefore, we investigated correlations between weather variability and patterns in occupancy, local colonisations and local extinctions (metapopulation metrics) across four groups of ectotherms: Odonata, Orthoptera, Lepidoptera, and Reptilia. We analysed data of 134 species on a 1×1 km-grid base, collected in the last 20 years from the Netherlands, combining standardised data and opportunistic data. We applied dynamic site-occupancy models and used the results as input for analyses of (i) trends in distribution patterns, (ii) the effect of temperature on colonisation and persistence probability, and (iii) the effect of years with extreme weather on all the three metapopulation metrics. All groups, except butterflies, showed more positive than negative trends in metapopulation metrics. We did not find evidence that the probability of colonisation or persistence increases with temperature nor that extreme weather events are reflected in higher extinction risks. We could not prove that weather extremes have visible and consistent negative effects on ectothermic species in temperate northern hemisphere. These findings do not confirm the general prediction that increased weather variability imperils biodiversity. We conclude that weather extremes might not be ecologically relevant for the majority of species. Populations might be buffered against weather variation (e.g. by habitat heterogeneity), or other factors might be masking the effects (e.g. availability and quality of habitat). Consequently, we postulate that weather extremes have less, or different, impact in real world metapopulations than theory and models suggest.
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