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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    Intertidal biofilm distribution underpins differential tide-following behavior of two sandpiper species (Calidris mauri and Calidris alpina) during northward migration
    Jimenez, A. ; Elner, R.W. ; Favaro, C. ; Rickards, K. ; Ydenberg, R.C. - \ 2015
    Estuarine Coastal and Shelf Science 155 (2015). - ISSN 0272-7714 - p. 8 - 16.
    fraser-river estuary - western sandpipers - shorebird distribution - sediment - waders - microphytobenthos - invertebrates - predation - abundance - cycle
    The discovery that some shorebird species graze heavily on biofilm adds importance to elucidating coastal processes controlling biofilm, as well as impetus to better understand patterns of shorebird use of intertidal flats. Western sandpipers (Calidris mauri) and dunlin (Calidris alpina) stopover in the hundreds of thousands on the Fraser River estuary, British Columbia, Canada, during northward migration to breeding areas. Western sandpipers show greater modification of tongue and bill morphology for biofilm feeding than dunlin, and their diet includes more biofilm. Therefore, we hypothesized that these congeners differentially use the intertidal area. A tide following index (TFI) was used to describe their distributions in the upper intertidal during ebbing tides. Also, we assessed sediment grain size, biofilm (= microphytobenthic or MPB) biomass and invertebrate abundance. Foraging dunlin closely followed the ebbing tide line, exploiting the upper intertidal only as the tide retreated through this area. In contrast, western sandpipers were less prone to follow the tide, and spent more time in the upper intertidal. Microphytobenthic biomass and sediment water content were highest in the upper intertidal, indicating greater biofilm availability for shorebirds in the first 350 m from shore. Invertebrate density did not differ between sections of the upper intertidal. Overall, western sandpiper behaviour and distribution more closely matched MPB biofilm availability than invertebrate availability. Conservation of sandpipers should consider physical processes, such as tides and currents, which maintain the availability of biofilm, a critical food source during global migration.
    Trade-offs between pasture production and farmland bird conservation: exploration of options using a dynamic farm model
    Sabatier, R. ; Teillard, F. ; Rossing, W.A.H. ; Doyen, L. ; Tichit, M. - \ 2015
    Animal 9 (2015)5. - ISSN 1751-7311 - p. 899 - 907.
    grassland agroecosystem - viability model - management - biodiversity - heterogeneity - populations - habitat - waders
    In European grassland landscapes, grazing and mowing play a key role for the maintenance of high-quality habitats that host important bird populations. As grasslands are also key resources for cattle feeding, there is a need to develop management strategies that achieve the double objective of production and biodiversity conservation. The objective of this study was to use a modelling approach to generate recognisable patterns of bird dynamics in farms composed of different land use proportions, and to compare their production and ecological dimensions. We developed a dynamic model, which linked grassland management to bird population dynamics at the field and farm levels. The model was parameterised for two types of suckling farms corresponding to contrasting levels of grassland intensification and for two bird species of high conservation value. A viability algorithm was used to define and assess viable management strategies for production and ecological performance so as to draw the shape of the relationship between both types of performances for the two types of farms. Our results indicated that, at the farm level, there was a farming system effect with a negative and non-linear relationship linking performance. Improving bird population maintenance was less costly in extensive farms compared with intensive farms. At the field level, the model predicted the timing and intensity of land use, maximising either production or ecological performance. The results suggested that multi-objective grassland management would benefit from public policies that consider levels of organisation higher than the field level, such as the farm or the landscape.
    Shorebird incubation behviour and its influence on the risk of nest predation
    Smith, P.A. ; Tulp, I.Y.M. ; Schekkerman, H. ; Gilchrist, H.G. ; Forbes, M.R. - \ 2012
    Animal Behaviour 84 (2012)4. - ISSN 0003-3472 - p. 835 - 842.
    daily energy-expenditure - site selection - parent birds - sandpipers - defense - pigmentation - patterns - habitat - success - waders
    Both nest survival and incubation behaviour are highly variable among shorebirds (Charadrii), and we tested whether more conspicuous incubation behaviour increased the risk of nest predation. During 2000-2006, we monitored nest fate at 901 shorebird nests at three study sites across the circumpolar Arctic. Using miniature video recorders and nest temperature sensors, we obtained 782 days of behavioural data for 161 nests of 11 species. We related nest fate to the rate and duration of adults' nest absences or restless movements on the nest, as well as the total proportion of each day that adult birds engaged in these activities. Nest predation was positively related to the proportion of time that each species left the nest unattended. After controlling for species effects, the likelihood of a successful nesting attempt was lower for individuals that spent more time off the nest, but among failed nests, the number of days that a nest survived prior to depredation was not significantly predicted by measures of incubation behaviour. To control for weather or seasonal effects, we paired observations from nests that were ultimately depredated with observations from successful nests of the same species on the same day. In this paired sample (dominated by two species: red phalaropes, Phalaropus fulicarius, and little stints, Calidris minuta), both incubation recesses and restless movements were more numerous among failed versus successful nests. Our results suggest that more conspicuous incubation behaviour is indeed related to a higher risk of nest predation, and that this relationship may underlie patterns of nest survival within and among shorebird species. (C) 2012 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
    ANT Oosterschelde: Long-term trends of waders and their dependence on intertidal foraging grounds
    Troost, K. ; Ysebaert, T. - \ 2011
    Yerseke : IMARES (Report / IMARES Wageningen UR C063/11) - 100
    waadvogels - habitats - foerageren - natuurbescherming - natura 2000 - estuaria - oosterschelde - waders - habitats - foraging - nature conservation - natura 2000 - estuaries - eastern scheldt
    The ANT study (“Autonomous Negative Trend” of the Oosterschelde estuary) aims to deliver the scientific support needed to assess the feasibility and affordability of the different conservation goals of Natura 2000. The main aim is to advise in which locations in the Oosterschelde estuary what kind of measures can be taken in order to meet (part of) the Natura2000 conservation goals for quality and quantity of the habitat of protected shorebird species. To meet this aim we first need to get insight in how the birds use the intertidal areas, and what factors determine their presence. That we do not fully understand the autonomous trends in bird numbers is clear from a discrepancy between expected and observed trends in wader numbers. Although we would expect to see declining wader numbers because of the ongoing erosion of the intertidal, we in fact see steady and even increasing numbers of several species. The present study aims to describe and explain observed trends in bird numbers by exploring relationships between bird numbers and biotic and morphological changes in the intertidal area of the Oosterschelde estuary.
    Aantalontwikkelingen van wadvogels in de Nederlandse Waddenzee in 1990-2008 : verschillen tussen oost en west (themanummer Waddenzee)
    Ens, B.J. ; Winden, E.A.J. ; Turnhout, C.A.M. van; Roomen, M.W.J. van; Smit, C.J. ; Jansen, J.M. - \ 2010
    Limosa 82 (2010)3/4. - ISSN 0024-3620 - p. 100 - 112.
    vogels - kustgebieden - wadden - waadvogels - birds - coastal areas - tidal flats - waders
    In het begin van de jaren negentig werd de Waddenzee getroffen door de grote schelpdiercrisis. Droogvallende mosselbanken verdwenen bijna allemaal en de kokkelbestanden bereikten een historisch dieptepunt. Sindsdien zijn de schelpdierbestanden op de droogvallende platen beter beschermd en heeft ook herstel plaatsgevonden. Je zou verwachten dat dit doorwerkt in de aantallen wadvogels die de Waddenzee bevolken. Maar is dat ook zo?. Een bijdrage van SOVON en IMARES
    An Atlas of Wader Populations in Africa and Western Eurasia
    Delany, S. ; Scott, D. ; Helmink, A.T.F. ; Dodman, T. ; Flink, S. ; Stroud, D. ; Haanstra, L. - \ 2009
    London : Wetlands International - ISBN 9789058820471 - 524
    populatie-ecologie - conservering - zoögeografie - afrika - europa - waadvogels - vogeltrek - population ecology - conservation - zoogeography - africa - europe - waders - bird migration
    This publication is a compilation of current knowledge of the numbers, distribution and movements of one of the most remarkable groups of birds in the region covered by the African-Eurasian Migratory Waterbird Agreement (AEWA). Long-term waterbird count data have been combined with an extensive literature review, especially published results of bird ringing and national bird atlases, to produce maps showing the population boundaries that are used as a basis of the conservation of these species. The maps are supported by informative species accounts that highlight the movements, population status and conservation of waders in the AEWA region.
    Body condition of shorebirds upon arrival at their Siberian breeding grounds
    Tulp, I.Y.M. ; Schekkerman, H. ; Klaassen, R.H.G. ; Ens, B.J. ; Visser, G.H. - \ 2009
    Polar Biology 32 (2009)3. - ISSN 0722-4060 - p. 481 - 491.
    calidris-canutus-islandica - red knots - energy-expenditure - tundra arthropods - ellesmere-island - fat reserves - migration - stores - survival - waders
    Abstract Arctic breeding shorebirds carry substantial body stores on their long-distance migrations from their non-breeding grounds. Upon arrival at the breeding area the remains of these stores can be used for egg formation, insurance against poor feeding conditions or rebuilding organs. We quantified body condition (body mass, total body water, lean body mass and fat mass estimated using the deuterium dilution method) in seven shorebird species caught upon arrival in the Siberian Arctic. Arrival condition was compared with incubation condition in a subset of species. After correction for structural size, body mass was significantly lower at arrival than during incubation in most of the species (but 3¿18% above lean mass). Fat index (fat mass/lean mass) varied between 5.1 and 13.2%. Fat stores were estimated to enable survival for 0.6 days for the smallest and 2.5 days for the largest species. We discuss possible functions of arrival stores: insurance, egg-formation or rebuilding organs.
    Energetic demands during incubation and chick rearing in a uniparental and a biparental shorebird breeding in the high Arctic
    Tulp, I.Y.M. ; Schekkerman, H. ; Bruinzeel, L. ; Jukema, J. ; Visser, G.H. ; Piersma, T. - \ 2009
    The Auk : a quarterly journal of ornithology 126 (2009)1. - ISSN 0004-8038 - p. 155 - 164.
    labeled water method - temperature regulation - expenditure - birds - allocation - waders - reproduction - validation - sandpipers - patterns
    Rearing of young has long been considered the energetically most demanding phase of the avian breeding cycle. Arctic-breeding shorebirds expend large amounts of energy during breeding. Because they are too small to carry sufficient stores to sit out the incubation period, they regularly interrupt incubation to feed and still can run short of energy, particularly in species in which one adult takes care of the eggs and chicks alone (uniparental). We measured daily energy expenditure (DEE) and time budgets during incubation and chick rearing in the smallest uniparental Arctic shorebird, the Little Stint (Calidris minuta). Daily energy expenditure decreased with increasing temperature but did not differ between the incubation and chick-rearing periods. Because of the increase in potential foraging time from incubation to the chick-rearing phase, the foraging intake rate required to balance the budget dropped by two-thirds. To evaluate the effect of uniparental care on energy budgets, we also measured DEE in the Dunlin (C. alpina), a sympatric congener in which both parents incubate but the female deserts the brood after hatching. Daily energy expenditure decreased with temperature, was the same during incubation and chick rearing, and was higher in males. Our results are discussed in relation to the timing of breeding of Arctic shorebirds with different systems of parental care. Received 31 October 2007, accepted 28 September 2008.
    Meadow bird ecology at different spatial scales : responses to environmental conditions and implications for management
    Verhulst, J. - \ 2007
    Wageningen University. Promotor(en): Frank Berendse, co-promotor(en): David Kleijn. - [S.l.] : S.n. - ISBN 9789085047551 - 136
    vogels - dierecologie - grondwaterstand - nestelen - milieufactoren - habitats - conservering - nederland - weidevogels - agrarisch natuurbeheer - waadvogels - birds - animal ecology - groundwater level - nesting - environmental factors - habitats - conservation - netherlands - grassland birds - agri-environment schemes - waders
    Het aantal weidevogels in Nederland loopt schrikbarend terug. Zo daalde het aantal broedende grutto’s de afgelopen twintig jaar van 100 duizend naar 45 duizend. Dit ondanks het feit dat de overheid jaarlijks circa 30 miljoen besteedt aan weidevogelbescherming op het boerenland. Boeren kiezen vooral voor twee maatregelen: later maaien en nestbescherming. Jort Verhulst kwam er in zijn promotieonderzoek achter dat dit niet de meest effectieve maatregelen zijn
    Voedselecologie van een zestal schelpdieretende vogels
    Brinkman, A.G. ; Leeuw, J.J. de; Leopold, M.F. ; Smit, C.J. ; Tulp, I.Y.M. - \ 2007
    Den Hoorn : IMARES Texel (Rapport / IMARES nr. C078/07) - 122
    vogels - kustgebieden - voedingsvoorkeuren - schaaldieren - schaal- en schelpdierenvisserij - vergunningen - waadvogels - Nederland - birds - coastal areas - feeding preferences - shellfish - shellfish fisheries - permits - waders - Netherlands
    Er is bij zittingen van Raad van State met betrekking tot de vergunningverlening van schelpdiervisserij regelmatig sprake van verschil in wetenschappelijk inzicht over wat de voedselpreferentie is van schelpdieretende vogels in Waddenzee. Het gaat hierbij om: Zwarte Zee-eend, Topper, Eider, Scholekster, Kanoet en Steenloper. Voor dit zestal vogelsoorten is samengevat wat hun status is, hun trekstrategie, hun voedselecologie en energiebehoefte en eventuele bedreigingen, en is aangegeven op welke terreinen er wezenlijke kennisleemtes liggen.
    Draagkracht en exoten in de Waddenzee
    Brinkman, A.G. ; Jansen, J.M. - \ 2007
    Den Burg / Yerseke : IMARES (Rapport / Wageningen IMARES nr. C073/07) - 34
    biocenose - biotopen - aquatisch milieu - biomassa productie - ecologisch evenwicht - draagkracht - populatiedichtheid - schaaldieren - kokkels - mossels - oesters - ensis - diervoeding - vogels - watervogels - waadvogels - waddenzee - biocoenosis - biotopes - aquatic environment - biomass production - ecological balance - carrying capacity - population density - shellfish - clams - mussels - oysters - ensis - animal nutrition - birds - waterfowl - waders - wadden sea
    In het kader van het Nationaal Programma voor Zee- en Kustonderzoek is inzicht gewenst in de draagkracht van het gebied. In dit kader is gekeken wat de verwachte toename van exoten binnen het Waddensysteem is. Het betreft hier de Japanse oester en de Amerikaanse zwaardschede
    Modelling the distribution of waders in the Westerschelde; what is the predictive power of abiotic variables?
    Ens, B.J. ; Brinkman, A.G. ; Dijkman, E.M. ; Meesters, H.W.G. ; Kersten, M. ; Brenninkmeijer, A. ; Twisk, F. - \ 2005
    Wageningen : Alterra (Alterra-rapport 1193) - 140
    getijden - voedingsgedrag - milieufactoren - vogels - wetlands - nederland - waadvogels - westerschelde - tides - feeding behaviour - environmental factors - birds - wetlands - netherlands - waders - western scheldt
    Evaluatie weidevogelbeleid : achtergronddocument bij Natuurbalans 2004
    Melman, T.C.P. ; Schotman, A.G.M. ; Hunink, S. - \ 2004
    Wageningen : Natuurplanbureau (Planbureaurapporten 9) - 66
    vogels - graslanden - natuurbescherming - evaluatie - milieubeheer - milieubeleid - populatie-ecologie - biotopen - nederland - overheidsbeleid - landbouwministeries - weidevogels - waadvogels - agrarisch natuurbeheer - birds - grasslands - nature conservation - evaluation - environmental management - environmental policy - population ecology - biotopes - netherlands - government policy - ministries of agriculture - grassland birds - waders - agri-environment schemes
    Alterra heeft voor het Milieu- en Natuurplanbureau het weidevogelbeleid geanalyseerd. Daarbij is aandacht geschonken aan de (ontwikkeling van) beleidsdoelstellingen, de ontwikkeling van de weidevogelpopulatie, de natuurwetenschappelijke basis van de beheervoorschriften en de uitvoering van de beheerregelingen. De aandacht is gericht op het (betaalde) beheer door agrariërs en terreinbeherende organisaties. Het beheer door vrijwilligers is niet in de analyses meegenomen. Gekeken is of van de huidige beheerregimes effecten verwacht mogen worden. Daarnaast is in een aantal generieke analyses gekwantificeerd in hoeverre de locatie van de huidige beschikkingen adequaat is. Het gaat daarbij om vragen als: welk deel van de beschikkingen ligt (1) binnen (belangrijke) weidevogelgebieden; (2) buiten de verstoringinvloed van wegen; (3) binnen voldoende open landschap en (4) buiten gebieden met zware predatie? Deze analyses geven een indicatie van het wel- of niet effectief kunnen zijn van het beheer. Met deskundigen (afkomstig uit onderzoek, beleid en beheer) zijn twee workshops gehouden, waarin de resultaten zijn besproken en van gedachte is gewisseld over de wijze waarop in Nederland aan de weidevogels perspectief kan worden geboden. De geschetste zoekrichting geniet een breed draagvlak. Centraal daarbij stond de noodzaak voor aandacht voor alle aspecten van het weidevogelbiotoop en de urgentie van ruimtelijke focussing van het beleid. Trefwoorden: Agrarisch natuurbeheer, weidevogelbeleid, evaluatie
    Studies on breeding shorebirds at Medusa Bay, Taimyr, in Summer 2002
    Schekkerman, H. ; Tulp, I.Y.M. ; Calf, K.M. ; Leeuw, J.J. de - \ 2004
    Wageningen : Alterra (Alterra-rapport 922) - 101
    vogels - nestelen - voortplanting - monitoring - arctische gebieden - predatie - geleedpotigen - rusland - waadvogels - birds - nesting - reproduction - monitoring - arctic regions - predation - arthropods - russia - waders
    In the summer of 2002 a combined Dutch-Russian expedition took place to the Willem Barentz field station at Medusa Bay near Dikson in north-western Taimyr, Russia. The expedition was organised by Alterra and the Agricultural Department of the Dutch Embassy in Moscow. Research questions addressed by the Alterra team and basic results obtained during the 2002 season are presented in this report. More elaborate analyses and discussion of the data will be made elsewhere. Where useful, results are compared with data collected in 2000 and 2001. Subjects of study generally concerned breeding biology of arctic breeding shorebirds, especially with respect to timing of breeding.
    Wader energy balance & tidal cycle simulator WEBTICS; technical documentation Version 1.1
    Rappoldt, C. ; Ens, B.J. ; Kersten, M.A.J.M. ; Dijkman, E.M. - \ 2004
    Wageningen : Alterra (Alterra-rapport 869) - 95
    schaaldieren - voedingsgedrag - schaal- en schelpdierenvisserij - energiebalans - getijden - foerageren - modellen - vogels - waadvogels - shellfish - feeding behaviour - shellfish fisheries - energy balance - tides - foraging - models - birds - waders
    This report describes the Wader Energy Balance and Tidal Cycle Simulator WEBTICS. The model simulates food uptake of Oystercatchers (Haematopus ostralegus) and a distribution of the birds over exposed parts of tidal areas. The mudflats are described on input as a number of spots which have a position, height and surface area. Spots may contain prey items characterized by type, weight and density. The program simulates tidal cycles and calculates the fraction of time the average and ideal bird has to spend feeding in order to meet its energy requirements. These foraging intensities are combined into a stress index for the winter. Besides historical data on weather, prey distribution, tides and fishing, there are bird and prey parameters on foraging, prey growth and energy conversion. Model output files can be processed in a spreadsheet. Also bitmapped images and movies are produced.
    Differential moult patterns in relation to antipredator behaviour during incubation in four tundra plovers
    Jukema, J. ; Tulp, I.Y.M. ; Bruinzeel, L. - \ 2003
    Ibis 145 (2003)2. - ISSN 0019-1019 - p. 270 - 276.
    lesser golden-plovers - waders - protection - molt
    Golden plovers and Grey Plovers Pluvialis spp. all have very distinct breeding plumage rich in contrast, with a conspicuous black belly and breast bordered by a bright white fringe. Eurasian Golden Plovers are known partly to replace their breeding plumage with striped yellow feathers during incubation, different from both breeding and non-breeding plumages. In this study a similar partial breeding moult was observed in Pacific Golden Plovers and American Golden Plovers caught on the nest or collected during incubation, although the feathers did not differ clearly from those of non-breeders. This moult starts during incubation and precedes the post-breeding moult into non-breeding plumage. Because the lighter feathers reduce the contrast between the black belly and the white flanks, we suggest that during incubation the plumage characteristic that plays an important role in mate choice is no longer important; at this stage it is better for the bird to be inconspicuous. Additional information on museum skins of golden plovers and of Grey Plovers indicated that only the three golden plovers undergo this partial moult, but that Grey Plovers in general retain full breeding plumage throughout incubation. The three golden plovers also resemble each other in their generally very passive nest defence strategies. In contrast, the larger Grey Plovers actively chase and attack aerial and ground predators. Thus, a reduced conspicuousness of the body plumage during incubation is likely to benefit the golden plovers more than the Grey Plover. We suggest that nest defence behaviour, plumage characteristics and perhaps size have co-evolved as a response to different selection pressures in golden plovers and Grey Plover, but alternative hypotheses are also discussed.
    Scholeksters en hun voedsel in de Waddenzee
    Rappoldt, C. ; Ens, B.J. ; Bult, T.P. ; Dijkman, E.M. - \ 2003
    Wageningen : Alterra (Alterra-rapport 882) - 152
    vogels - charadriiformes - populatiedynamica - voedingsgedrag - schaaldieren - mossels - schaal- en schelpdierenvisserij - milieueffect - ecologie - nederland - waddenzee - waadvogels - oosterschelde - birds - charadriiformes - population dynamics - feeding behaviour - shellfish - mussels - shellfish fisheries - environmental impact - ecology - netherlands - wadden sea - waders - eastern scheldt
    Dit rapport bevat een analyse van de voedselsituatie van scholeksters gedurende de negentiger jarenin de Waddenzee. Het aantal overwinterende scholeksters is afgenomen van 266 000 in de jaren tachtig tot 170 000 aan het eind van de jaren negentig. De oorzaak is een tekort aan voedsel dat in de eerste plaats is veroorzaakt door het ontbreken van mosselbanken die rond 1990 zijn verdwenen ten gevolge van strenge winters, bevissing en stormen. De tweede oorzaak is de kokkelvisserij die de draagkracht van het Waddengebied voor scholeksters met ongeveer 12% heeft verminderd. De hoeveelheid voedsel die nodig is voor een stabiel aantal scholeksters bedraagt naar schatting 200 kg kokkelvlees per scholekster of 1 ha stabiele mosselbank voor iedere 35 scholeksters. Aan het eind van de negentiger jaren was die hoeveelheid kokkelvlees aanwezig en is het aantal scholeksters ook weer licht gestegen.
    Effects of a missile launching on waders and other waterbirds in the Meldorfer Bucht, Germany
    Smit, C.J. ; Jong, M.L. de - \ 2002
    Wageningen : Alterra (Alterra-rapport 497) - 41
    helikopters - duitsland - vogels - watervogels - effecten - waadvogels - verstoring - waddenzee - militaire activiteiten - helicopters - germany - birds - waterfowl - effects - waders - disturbance - wadden sea - military activities
    Missile tests in the Meldorfer Bucht have been under debate for many years, especially since the test area has become part of the National Park Schleswig Holsteinisches Wattenmeer. Alterra Texel, as an independent institute involved in biological research in the Wadden Sea for many years, has been asked to quantify the effects of these tests by means of a brief field study. The results presented in this report are based on observations during a single observation day. Our results are combined with theoretical predictions and data from earlier studies. It appears that the use of helicopters for making clear range flights and for collecting the remains of the missile from the mudflats have the highest impact, especially because of disturbance of birds. Some thousands of waders and other waterbirds are disturbed briefly. The impact of these disturbances, expressed as extra energy expenditure for birds, can be classified as small. The number of macrobenthic animals (like worms and shellfish) killed by the missile landing on the tidal flats can be classified as very small. Although our study has been short and relatively superficial we believe that the results can be considered as a valid expert opinion on the most relevant implications of the impact of weapon technology trials in this area.
    Vogelkundige waarden van de polder Zeevang, 1996-2001; een evaluatie in het kader van de EG-Vogelrichtlijn
    Schekkerman, H. ; Beintema, A.J. - \ 2002
    Wageningen : Alterra (Alterra-rapport 450) - 29
    anas - vogels - richtlijnen (directives) - bescherming - monitoring - nederland - waadvogels - ecologie - fauna - ornithologie - trekvogels - watervogels - Noord-Holland - anas - birds - directives - protection - monitoring - netherlands - waders - fauna
    In dit rapport worden de meest recente gegevens over het voorkomen van trekkende watervogelsoorten in de polder de Zeevang en omgeving (Noord-Holland) samengevat. Op grond van de drempeloverschrijdende aantallen overwinterende smienten (Anas penelope)wordt geadviseerd de Zeevang aan te wijzen als speciale beschermingszone onder de EG-Vogelrichtlijn.
    Searching for Slender-billed Curlews in Iran, January-February 2000
    Have, T.M. van der; Keijl, G.O. ; Mansoori, J. ; Morozov, V.V. - \ 2001
    Zeist : WIWO (WIWO-report 72 )
    numenius - vogels - watervogels - wetlands - inventarisaties - monitoring - iran - waadvogels - numenius - birds - waterfowl - wetlands - inventories - monitoring - iran - waders
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