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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    Forest development in a restored floodplain: effects of grazing, inundation and vegetation
    Cornelissen, Perry ; Decuyper, Mathieu ; Sýkora, Karlè ; Bokdam, Jan ; Berendse, Frank - \ 2019
    European Journal of Environmental Sciences 9 (2019)1. - ISSN 1805-0174 - p. 21 - 32.
    In many countries worldwide, measures have been taken in floodplains for flood prevention and nature rehabilitation. In the Netherlands, floodplains are lowered by excavating to enlarge the discharge capacity and to create opportunities for development of river habitats such as forest. As forest can obstruct the water flow through the floodplain, their development has to be controlled in some cases. In many floodplains, vegetation development is controlled by cattle and horses. We carried out an exclosure experiment over a twelve year period in a partly excavated and year-round grazed floodplain along a lowland river in the Netherlands. We focussed on the thorny shrub hawthorn (Crataegus monogyna Jacq.) as it plays an important role in the obstruction of the water flow and in the wood-pasture cycle. Most hawthorn shrubs established on the excavated part of the floodplain with low cover of tall herbs. The total number of established hawthorn was negatively related to inundation on the lower parts of the excavated sites and positively related to inundation on the higher parts of the excavated sites. The herbivores negatively affected establishment and growth of hawthorn. Although lowering the floodplain by excavation will increase discharge capacity of the floodplain in the short term, it will decrease in the long term as excavation also increases opportunities for floodplain forest. If flood prevention and nature rehabilitation are both goals to be achieved in a floodplain, hawthorn encroachment can be controlled by a clever design of the measures and grazing management is needed
    Habitat heterogeneity promotes intraspecific trait variability of shrub species in Australian granite inselbergs
    Smedt, P. de; Ottaviani, G. ; Wardell-Johnson, G. ; Sýkora, K.V. ; Mucina, L. - \ 2018
    Folia Geobotanica 53 (2018)2. - ISSN 1211-9520 - p. 133 - 145.
    Fire-refugia - Functional traits - Global biodiversity hotspot - Mediterranean-type climate - Plant resource strategies - Proteaceae
    The role of intraspecific trait variability is increasingly recognized as a key factor shaping plant fitness and community assembly worldwide. Studying the direct effects of habitat heterogeneity on trait expression of individual plants of the same species is a useful tool to quantify intraspecific trait variability locally. We investigated how habitat heterogeneity on granite inselbergs affected intraspecific trait variability of 19 functional traits in three shrub species of the family Proteaceae in south western Australia, a global biodiversity hotspot. We used pairwise comparison (single trait) and multivariate analysis (multiple traits, functional space) to detect shifts in trait patterns. Consistent with our predictions, we found that individuals developing in putatively more stressful habitats (highly sun-irradiated, shallow-soil patches on the outcrops) were characterized by trait expressions indicative of more conservative resource-related strategies when compared with plants occurring in the surrounding woodlands that were experiencing more benign ecological conditions. These results were significant for two out of three species. Granite inselbergs promoted plant longevity, a signal that these granite inselbergs might offer refugial conditions defined as protection against fire.
    Effect of Vachellia tortilis on understory vegetation, herbaceous biomass and soil nutrients along a grazing gradient in a semi-arid African savanna
    Yadeta, Temesgen ; Veenendaal, Elmar ; Sykora, Karle ; Tessema, Zewdu K. ; Asefa, Addisu - \ 2018
    Journal of Forestry Research 29 (2018)6. - ISSN 1007-662X - p. 1601 - 1609.
    Basal area cover - Grazing pressure - Inside/outside canopy - Soil moisture
    The spatial pattern and abundance of herbaceous vegetation in semi-arid savannas are dictated by a complex and dynamic interaction between trees and grasses. Scattered trees alter the composition and spatial distribution of herbaceous vegetation under their canopies. Therefore, we studied the effect of Vachellia tortilis on herbaceous vegetation composition, biomass and basal area, and soil nutrients on sites with varying grazing intensities in the central rift valley of Ethiopia. Data were collected on species composition, cover and biomass of herbs and grasses, and soil moisture and nutrient contents under light, medium, and heavy grazing pressures, both under the inside and outside of V. tortilis canopies. Species richness was similar in both locations but decreased with increased grazing. Only the overall biomass and herb cover were significantly greater under the canopy than outside, and overall biomass showed significant unchanging decline with increased grazing. However, vegetation cover was significantly greater on moderately grazed sites compared to low and heavily grazed sites. All soil variables were significantly higher under V. tortilis canopies than outside. Our findings suggest that V. tortilis has more effect on composition and diversity of herbaceous vegetation than on species richness, and that V. tortilis promotes the herbaceous layer biomass by reducing soil moisture loss and increasing soil fertility under the inside than outside the canopies. Therefore, we suggest that management practices should be directed on reducing pressure on V. tortilis by regulating grazing. Low to moderate grazing levels (i.e., a stocking rate less than 39.6 TLU ha −1 yr −1 ) seems to be tolerable to ensure sustainable conservation of the species in the study area in particular and in semi-arid savannas in general.
    Zandafzetting, standplaats, beheer en botanische kwaliteit van Stroomdalgrasland
    Rotthier, S.L.F. ; Sykora, K.V. ; Bekisa, B. ; Ras̆omavic̆ius, V. ; Makaske, A. ; Wallinga, J. ; Schipper, P. - \ 2016
    Driebergen : Vereniging van Bos- en Natuurterreineigenaren (Rapport nr. 2016/OBN-200-RI) - 196
    Het onderzoek naar de ecologie van stroomdalgrasland vond plaats langs zes riviertakken: de Gelderse IJssel (Cortenoever en Vreugderijkerwaard), de Lek (Koekoekswaard), de Maas (Oeffelter Meent), de Merwede (Kop van de Oude Wiel), de Overijsselse Vecht (Junner Koeland), de Waal (Millingerwaard en Erlecomsewaard).
    Species composition and phytosociology of xerophytic plant communities after extreme rainfall in South Peru
    Montesinos, D.B. ; Sykora, K.V. ; Quipuscoa-Silvestre, Victor ; Cleef, A.M. - \ 2015
    Phytocoenologia 45 (2015)3. - ISSN 0340-269X - p. 203 - 250.
    We present a phytosociological overview of the arid and semi-arid montane vegetation of the province of Arequipa in southern Peru. The xerophytic vegetation was studied after extreme rainfall had promoted exceptionally lush vegetation and a high aboveground floristic diversity. We used TWINSPAN for classification and Detrended Correspondence Analysis for gradient analysis of our relevés. PC-ORD was used to show the hierarchical similarity structure of the syntaxa, and to compare them with related communities in Peru and surrounding countries from literature. We present a synoptic table, and describe the physiognomy, floristic composition, ecology and spatial distribution of the plant communities. In total, we recorded 187 plant species, including 50 endemics, in 196 phytosociological relevés distributed over 2030 km2 at an elevation between 2020 and 3260 m a. s. l. The relevés were assigned to three alliances in the class Opuntietea sphaericae. The vegetation consists mainly of native species of trees, shrubs, grasses, succulents, annual herbs, and ferns. The most diverse families were Asteraceae, Cactaceae, Solanaceae, Malvaceae, Boraginaceae, Fabaceae, Poaceae, Amaranthaceae and Pteridaceae. Within the class Opuntietea sphaericae, three alliances have been distinguished of which two are new. The Ambrosio artemisioidis-Weberbauerocerion weberbaueri comprising six associations was recorded on barren hillsides between 2000 and 2900 m a. s. l. in the Arequipa city boundary zones. The Corryocaction brevistyli defines xerophytic scrub between 2700 and 3200 m a. s. l. in semi-dry regions bordering the puna grasslands. It contains the Balbisio weberbaueri-Ambrosietum artemisioidis and the Aloysio spathulatae-Corryocactetum brevistyli, all in need of further investigation as they lack diagnostic species. A unit clearly distinguished by Weberbauerocereus rauhii and Neoraimondia arequipensis is here described as a new alliance, Neoraimondio arequipensis-Weberbauerocerion rauhii. It grows in inter-Andean valleys in dry regions (1100– 2200 m a. s. l.), with abundant cacti accompanied by few xerophytes.
    The Puna vegetation of Moquegua, South Peru: Chasmophytes, grasslands and Puya raimondii stands
    Montesinos, D.B. ; Cleef, Antoine ; Sykora, K.V. - \ 2015
    Phytocoenologia 45 (2015)4. - ISSN 0340-269X - p. 365 - 397.
    The phytosociology and ecology of puna vegetation in twelve localities at an altitude of 3750–4500 m in northern Moquegua (south Peru) have been studied. The study area has a pluviseasonal climate with summer rainfall. Using TWINSPAN, Detrended Correspondence Analysis and Farthest Neighbor Clustering, 157 phytosociological relevés were analyzed. For each community, the syntaxonomy, floristic diversity and relation with environmental variables are discussed. 210 vascular plant species belonging to 131 genera and 52 families were recorded. Three main vegetation types were distinguished: 1. chasmophyte vegetation composed of a great diversity of shrubs, dwarf shrubs, ferns and annuals, 2. Puya raimondii stands characterized by considerable species richness in shrubs, grasses and herbs, and 3. extensive puna grasslands influenced by grazing. The zonal vegetation of the supratropical and orotropical bioclimatic belts was represented by two phytosociological classes: Argyrochosmetea niveae (chasmophytes) and Calamagrostietea vicunarum (Puya raimondii and puna grasslands). Within the Argyrochosmetea niveae and Salpichroetalia glandulosae, the new alliances Argyrochosmo niveae-Neowerdermannion peruvianae and Hypochaerido mucidae-Loricarion graveolentis were distinguished, including six associations consisting of steep rock and crevice shrublands on lithosols. Within the Azorello compactae-Festucion orthophyllae (Calamagrostietea vicunarum) two associations with four subassociations and two communities were distinguished comprising grasslands and Puya raimondii stands. One association was described in the Calamagrostion minimae. The puna vegetation of Moquegua hosts rare, endangered and/or protected plant species in Peru. The vulnerability of the flora and vegetation in the mountains of Moquegua is briefly discussed.
    Structural, physiognomic and above-ground biomass variation in savanna–forest transition zones on three continents– how
    Veenendaal, E.M. ; Torello-Raventos, M. ; Feldpausch, T.R. ; Domingues, T.F. ; Gerard, F. ; Schrodt, F. ; Saiz, G. ; Quesada, C.A. ; Djagbletey, G. ; Sykora, K.V. - \ 2015
    Biogeosciences 12 (2015). - ISSN 1726-4170 - p. 2927 - 2951.
    alternative stable states - tropical forest - cerrado vegetation - brazilian cerrado - woody vegetation - national-park - tree height - amazonian forest - functional types - southern africa
    Through interpretations of remote-sensing data and/or theoretical propositions, the idea that forest and savanna represent "alternative stable states" is gaining increasing acceptance. Filling an observational gap, we present detailed stratified floristic and structural analyses for forest and savanna stands located mostly within zones of transition (where both vegetation types occur in close proximity) in Africa, South America and Australia. Woody plant leaf area index variation was related to tree canopy cover in a similar way for both savanna and forest with substantial overlap between the two vegetation types. As total woody plant canopy cover increased, so did the relative contribution of middle and lower strata of woody vegetation. Herbaceous layer cover declined as woody cover increased. This pattern of understorey grasses and herbs progressively replaced by shrubs as the canopy closes over was found for both savanna and forests and on all continents. Thus, once subordinate woody canopy layers are taken into account, a less marked transition in woody plant cover across the savanna–forest-species discontinuum is observed compared to that inferred when trees of a basal diameter > 0.1 m are considered in isolation. This is especially the case for shrub-dominated savannas and in taller savannas approaching canopy closure. An increased contribution of forest species to the total subordinate cover is also observed as savanna stand canopy closure occurs. Despite similarities in canopy-cover characteristics, woody vegetation in Africa and Australia attained greater heights and stored a greater amount of above-ground biomass than in South America. Up to three times as much above-ground biomass is stored in forests compared to savannas under equivalent climatic conditions. Savanna–forest transition zones were also found to typically occur at higher precipitation regimes for South America than for Africa. Nevertheless, consistent across all three continents coexistence was found to be confined to a well-defined edaphic–climate envelope with soil and climate the key determinants of the relative location of forest and savanna stands. Moreover, when considered in conjunction with the appropriate water availability metrics, it emerges that soil exchangeable cations exert considerable control on woody canopy-cover extent as measured in our pan-continental (forest + savanna) data set. Taken together these observations do not lend support to the notion of alternate stable states mediated through fire feedbacks as the prime force shaping the distribution of the two dominant vegetation types of the tropical lands.
    Stroomdalgrasland, kort en laagdynamisch
    Sykora, K.V. ; Rotthier, S.L.F. - \ 2014
    De Levende Natuur 115 (2014)3. - ISSN 0024-1520 - p. 134 - 139.
    vegetatietypen - habitats - graslanden - geomorfologie - rivierengebied - begrazing - natuurbeheer - vegetation types - habitats - grasslands - geomorphology - rivierengebied - grazing - nature management
    Stroomdalgrasland was vóór 1960 algemeen, is sindsdien dramatisch achteruitgegaan en is vrijwel verdwenen. Na Plan Ooievaar en de invoering van het wildernisbeheer is langs de grote rivieren veel veranderd. De nadruk kwam in veel terreinen te liggen op 'vergroting van de dynamiek' en 'spontane begrazing'. Wat betekent dit voor stroomdalgrasland en wat is hiervoor het optimale beheer?
    Structural, physiognomic and aboveground biomass variation in savanna-forest transition zones on three continents. How different are co-occurring savanna and forest formations?
    Veenendaal, E.M. ; Torello-Raventos, M. ; Feldpausch, T.R. ; Domingues, T.F. ; Ceca, G. ; Sykora, K.V. - \ 2014
    Biogeosciences Discussions 11 (2014)3. - ISSN 1810-6277 - p. 4591 - 4636.
    Through interpretations of remote sensing data and/or theoretical propositions, the idea that forest and savanna represent "alternative stable states" is gaining increasing acceptance. Filling an observational gap, we present detailed stratified floristic and structural analyses for forest and savanna stands mostly located within zones of transition (where both vegetation types occur in close proximity) in Africa, South America and Australia. Woody plant leaf area index variation was related in a similar way to tree canopy cover for both savanna and forest with substantial overlap between the two vegetation types. As total woody plant canopy cover increased, so did the contribution of middle and lower strata of woody vegetation to this total. Herbaceous layer cover also declined as woody cover increased. This pattern of understorey grasses and herbs being progressively replaced by shrubs as canopy closure occurs was found for both savanna and forests and on all continents. Thus, once subordinate woody canopy layers are taken into account, a less marked transition in woody plant cover across the savanna-forest species discontinuum is observed compared to that implied when trees of a basal diameter > 0.1m are considered in isolation. This is especially the case for shrub-dominated savannas and in taller savannas approaching canopy closure. An increased contribution of forest species to the total subordinate cover is also observed as savanna stand canopy closure occurs. Despite similarities in canopy cover characteristics, woody vegetation in Africa and Australia attained greater heights and stored a greater concentration of above ground biomass than in South America. Up to three times as much aboveground biomass is stored in forests compared to savannas under equivalent climatic conditions. Savanna/forest transition zones were also found to typically occur at higher precipitation regimes for South America than for Africa. Nevertheless, coexistence was found to be confined to a well-defined edaphic/climate envelope consistent across all three continents with both soil and climate playing a role as the key determinants of the relative location of forest and savanna. Taken together these observations do not lend support the notion of alternate stable states mediated through fire-feedbacks as the prime force shaping the distribution of the two dominant vegetation types of the tropical lands.
    Effects of large herbivores on wood pasture dynamics in a European wetland system
    Cornelissen, P. ; Bokdam, J. ; Sykora, K.V. ; Berendse, F. - \ 2014
    Basic and Applied Ecology 15 (2014)5. - ISSN 1439-1791 - p. 396 - 406.
    sambucus-nigra l - associational susceptibility - red deer - vegetation - facilitation - mosaics - grassland - neighbors - patterns - litter
    Whether self-regulating large herbivores play a key role in the development of wood-pasture landscapes remains a crucial unanswered question for both ecological theory and nature conservation. We describe and analyse how a ‘partly self-regulating’ population of cattle, horses and red deer affected the development of the woody vegetation in the Oostvaardersplassen nature reserve (Netherlands). Using aerial photographs from 1980 to 2011, we analysed the development of shrubs and trees. Before the large herbivores were introduced in the Oostvaardersplassen in 1983, the woody vegetation increased and vegetation type significantly affected the number of establishments. Cover of woody species increased further from 1983 to 1996, not only by canopy expansion but also by new establishments. After 1996, cover of the woody vegetation decreased from 30% to
    On the delineation of tropical vegetation types with an emphasis on forest/savanna transitions
    Torello-Raventos, M. ; Feldpausch, T.R. ; Veenendaal, E.M. ; Sykora, K.V. - \ 2013
    Plant Ecology & Diversity 6 (2013)1. - ISSN 1755-0874 - p. 101 - 137.
    plant-communities - rain-forest - land-cover - african vegetation - physiognomic classification - ecological classification - cerrado vegetation - savanna vegetation - brazilian cerrado - climate-change
    Background: There is no generally agreed classification scheme for the many different vegetation formation types occurring in the tropics. This hinders cross-continental comparisons and causes confusion as words, such as ‘forest’ and ‘savanna’ have different meanings to different people. Tropical vegetation formations are therefore usually imprecisely and/or ambiguously defined in modelling, remote sensing and ecological studies. Aims: To integrate observed variations in tropical vegetation structure and floristic composition into a single classification scheme. Methods: Using structural and floristic measurements made on three continents, discrete tropical vegetation groupings were defined on the basis of overstorey and understorey structure and species compositions by using clustering techniques. Results: Twelve structural groupings were identified based on height and canopy cover of the dominant upper-stratum and the extent of lower-strata woody shrub cover and grass cover. Structural classifications did not, however, always agree with those based on floristic composition; especially for plots located in the forest-savanna transition zone. This duality is incorporated into a new tropical vegetation classification scheme. Conclusions: Both floristics and stand structure are important criteria for the meaningful delineation of tropical vegetation formations, especially in the forest/savanna transition zone. A new tropical vegetation classification scheme incorporating this information has been developed.
    Andean shrublands of Moquegua, South Peru: Prepuna plant communities
    Montesinos, D.B. ; Cleef, A.M. ; Sykora, K.V. - \ 2012
    Phytocoenologia 42 (2012)1-2. - ISSN 0340-269X - p. 29 - 55.
    northern chile - climate-change - vegetation
    A syntaxonomic overview of shrubland vegetation in the southern Andean regions of Peru is presented. For each plant community, information is given on physiognomy, floristic diversity, ecology and geographical distribution. The shrub vegetation on the slopes of the upper Tambo river valley includes annual herbs, grasses, cacti and ferns. In total, 151 vascular species have been documented from forty-six relevés made at altitudes between 3470 and 3700 m. After classification with TWINSPAN, one class, one order, one alliance, three associations, two subassociations typicum and three subassociations, one variant, and two communities are distinguished. Hierarchically the class Echinopsio schoenii-Proustietea cuneifoliae comprises the order Echinopsio schoenii-Proustetalia cuneifoliae, and the alliance Salvion oppositiflorae, occurring in the Prepuna dwarf scrubs. Within the alliance the following 3 new associations (with subassociations) have been distinguished: Senecioni arnaldii-Exhalimolobetum weddellii (thorny rosette-like dwarf shrubs), Mostacillastro gracile-Chuquiragetum spinosae (high cover of shrubs) and Anredero diffusae-Diplostephietum meyenii (high cover of clustered columnar cacti and patches of thorny shrubs). Two communities have been distinguished: Opuntia rosea and Helogyne ferreyrae, and the community of Ophryosporus heptanthus and Escallonia myrtilloides, which includes several introduced species growing on heavily grazed wet slopes. The basal communities of Stipa ichu and Nassella asplundii have been also identified. The most diverse families are Asteraceae, Poaceae and Cactaceae, followed by Solanaceae and Fabaceae. The vegetation includes endemic, native and a few introduced species. DCA was used to interpret the correlation between environmental variables and species composition. Species composition is best explained by altitude, inclination and vegetation cover.
    Towards the Hellenic National Vegetation Database: VegHellas
    Dimopoulos, P. ; Tsiripidis, I. ; Bergmeier, E. ; Sykora, K.V. - \ 2012
    Plant sociology 49 (2012)2. - ISSN 2280-1855 - p. 81 - 87.
    Abstract Recently a new initiative was launched aimed at building a central database to hold all so far published and unpublished relevés available in Greece – the Hellenic National Vegetation Database (VegHellas). All literature sources, widely dispersed and often poorly accessible, containing vegetation relevés from Greece have been compiled and stored in a bibliographical database. To date this database houses more than 200 references. Between 1944 and 2011, more than 30,000 phytosociological relevés were made in Greece, and these are stored either as hard copies or electronically. Currently, data on more than 22,000 vegetation plots, entered in the TURBOVEG database system are georeferenced to a certain level of precision (e.g. mountain range, mountain peak, specific locality, island, phytogeographical region, grid cell 10 x 10 km etc.). Plant nomenclatural problems, such as the use of different synonyms for the same taxon by different researchers in different years will be solved using the standardized Hellenic Vascular Plant Checklist (HVPC), currently close to completion. This checklist will offer a scientific basis for consistent nomenclatural reference. A database with chorological, life-form and other plant-trait information for each taxon, will also be linked to the vegetation-plot records. This will allow using VegHellas not only as a tool for the formulation of a national system of vegetation classification, but also in multiple applications in ecological, biogeographical and applied environmental research. The preparation of a syntaxonomic overview of the vegetation of Greece is currently in progress. Following the basic principles of the checklist of high-rank syntaxa of the European vegetation, the Hellenic syntaxa checklist will be produced down to the syntaxonomic level of alliance to serve as a precursor of a full syntaxonomic checklist including all associations.
    De ecologie van stroomdalgrasland; in het bijzonder de invloed van zandafzetting. Resultaten eerste onderzoeksfase
    Rotthier, S.L.F. ; Sykora, K.V. - \ 2012
    Den Haag : Bosschap, Directie Kennis en Innovatie, Ministerie van Economische Zaken, Landbouw en Innovatie
    plantengemeenschappen - bodem-plant relaties - graslanden - habitats - stroomdalen - geomorfologie - rivierengebied - plant communities - soil plant relationships - grasslands - habitats - stream valleys - geomorphology - rivierengebied
    Droog stroomdalgrasland (oeverwal of rivierduingrasland) is zeer kenmerkend voor het rivierengebied. Oppervlak en kwaliteit zijn echter sterk achteruitgegaan. Droge stroomdalgraslanden kwamen vóór 1960 vrijwel overal langs de grote rivieren voor en zijn daarna uit 83-84% van de kilometerhokken verdwenen. Voor instandhouding van deze waardevolle graslanden is een goed begrip nodig van de standplaatsomstandigheden. Daarom is de ecologische amplitude van de verschillende stroomdal grasland gemeenschappen onderzocht.
    Vegetation succession and habitat restoration in Dutch lichen-rich inland drift sands
    Ketner-Oostra, R. ; Aptroot, A. ; Jungerius, P.D. ; Sykora, K.V. - \ 2012
    Tuexenia 32 (2012). - ISSN 0722-494X - p. 245 - 268.
    campylopus-introflexus - netherlands
    Between 1996 and 2006 the vegetation succession in drift sands and in blown-out gravel-rich depressions, located in the nature reserve Hulshorsterzand in the central Netherlands, was studied. Within this Natura 2000 habitat (type 2330: inland dunes with o
    Effect van overstuiving op korstmosrijke duinen op Terschelling
    Ketner-Oostra, R. ; Sykora, K.V. - \ 2012
    De Levende Natuur 113 (2012)4. - ISSN 0024-1520 - p. 167 - 173.
    duingebieden - duinplanten - vegetatietypen - grassen - nederlandse waddeneilanden - friesland - duneland - duneland plants - vegetation types - grasses - dutch wadden islands - friesland
    De botanische verscheidenheid in kalkarme droge duinen wordt o.a. door korstmossen gevormd. Sinds de jaren 80 van de vorige eeuw zijn deze duinen in het Waddendistrict sterk veranderd door vergrassing met Helm en Zandzegge en vermossing met Grijs kronkelsteeltje. Kan overstuiving met vers zand deze uniformiteit doorbreken? Jarenlange monitoring van de vegetatie op Terschelling geeft hier het antwoord op.
    Successful overwintering of arthropods in roadside verges
    Schaffers, A.P. ; Raemakers, I.P. ; Sykora, K.V. - \ 2012
    Journal of Insect Conservation 16 (2012)4. - ISSN 1366-638X - p. 511 - 522.
    species composition - beetles coleoptera - conservation value - carabid beetles - abundance - assemblages - hymenoptera - dispersal - corridors - diversity
    In densely populated areas, roadside verges often provide the last semi-natural habitats available. Their ecological value is often stressed by bio survey results. Yet insect summer surveys potentially misjudge the value of a biotope (roadside or otherwise) since the occurrences of species may only be seasonal, or even transient. To effectively ascertain the importance of a site for insects, species must be shown to complete their life cycle there or at least be shown to successfully accomplish critical life stages, such as reproduction or overwintering. To confirm overwintering of arthropods in roadsides, sods were cut in late winter in a verge where several years of summer survey data were available. The sods were placed in transparent semi-permeable cages and kept alive during subsequent spring, summer and autumn. All emerging arthropods were caught inside the cages using pitfall and funnel traps and identified to order or family level. Most of the terrestrial arthropod phyla and orders occurring in NW-Europe appeared to be represented. Several groups were further identified to the species level: Carabidae (Coleoptera), Curculionidae (Coleoptera), Araneae, Orthoptera, Apidae (Hymenoptera), Syrphidae (Diptera) and Dephacidae/Cercopidae (Hemiptera). Particularly for the Carabidae, Araneae and Curculionidae, many species recorded in summer were also found to overwinter; species overlap amounted to approximately 67%. Rarefaction of the summer sample or excluding possible summer vagrants, raised this overlap to as much as 88% for the Carabidae. Many of the species successfully overwintering in the roadside verge were generalists, but less common, more stenotopic species were present as well. Not only species hibernating as adults were involved, but also species overwintering in immature stages, indicating reproduction also takes place in the roadside verge. Apparently the roadside occurrence of many arthropod species, including stenotopic and declining ones, is not merely seasonal or incidental, and roadside verges do not necessarily act as a sink only. The ecological importance often attributed to roadside verges should clearly be taken seriously.
    Dry sandy levee grasslands in the Netherlands and an intended syntaxonomic European overview
    Sykora, K.V. ; Rotthier, S.L.F. ; Schaminee, J.H.J. - \ 2011
    In: 20th International Workshop of the European Vegetation Survey, A century of phytosociology & 20 years of the new spirit in phytosociology, Rome, Italy, 6 - 9 April, 2011. - - p. 56 - 56.
    Along rivers sand is deposited and sandy levees develop. In the Netherlands two grassland associations are distinguished that are characteristic of dry, relatively nutrient poor, calcium containing, sandy levees, the Medicagini-Avenetum pubescentis De Leeuw in Braun Blanquet et Moor 1938, Sedo-Thymetum pulegioides Doing ex Weeda, Doing et Schamine and Festuco-Thymetum serpylii Tuxen 1937. Their syntaxonomic position is still partly disputed (Sedo-Cerastion, Meso-Bromion, Plantagini-Festucion). According to our historical research, nowadays the quality of these grasslands changed and they strongly declined (surface decrease more than 90% in last decades) and are rare and threatened. In the habitat directives dry fluviatile grasslands are designated as habitat types with priority. In 2010 we started a research into the ecological amplitude of fluviatile grassland communities and their characteristic species and the influence of sand deposition. In this presentation we will report about a plan to compare the site conditions in the Netherlands with those in some other countries like Latvia, Lithuania and Germany. Besides we plan a project to study the syntaxonomic position of the sandy levee communities in the Netherlands in comparison with the syntaxonomy of comparable grasslands in other European countries. Species like Artemisia campestris, Thalictrum minus, Veronica prostrata, Veronica austriaca ssp. teucrium, Thymus serpyllum, T. pulegioides, Sedum sexangulare, S. reflexum, S. album, Salvia pratensis, Potentilla verna, Plantago media, Medicago falcata, Herniaria glabra, Galium verum, Euphorbia cyparissias, E, seguieriana, Eryngium campestre, Dianthus deltoids, Cynodon dactylon, Cerastium arvense, Carex caryophyllea, Pimpinella saxifraga, Sanguisorba minor, Koeleria macrantha, Helictotrichon pubescens, Trifolium striatum and Orobanche lutea were used for relevé selection. Thanks to the kind cooperation of several countries and colleagues our database is growing and already contains or will contain relevés from Belgium, Germany, France, Great Britain, Ireland, Latvia, Lithuania, Austria, The Netherlands, Slovakia, the Czech republic and the Volga region
    Using movement and habitat corridors to improve the connectivity for heathland carabid beetles
    Noordijk, J. ; Schaffers, A.P. ; Heijerman, Th. ; Sykora, K.V. - \ 2011
    Journal for Nature Conservation 19 (2011)5. - ISSN 1617-1381 - p. 276 - 284.
    plant-species composition - roadside verges - coleoptera - dispersal - vegetation - conservation - diversity - restoration - netherlands - populations
    Heathland areas in the Netherlands are declining in size and quality, and becoming more fragmented. The connectivity of the landscape for threatened insects might be improved by creating networks of corridors.We compared heathy roadside verges and linear forest clearings with heathland nature reserves and forests. The clearings were created in between the roadside verges and the nature reserves. In all four landscape types carabid beetles were inventoried with pitfall and window traps. Principal Component Analyses showed that the carabid species composition in roadside verges differed from that in nature reserves, both before and after the creation of the connecting forest clearings. However, an analysis of data on 31 target species (stenotopic species of drift sand, heathland and other nutrient-poor open habitats) selected from the pitfall trap catches revealed that 21 were present in the roadside verges. In addition, the occurrence of teneral individuals and flightless species indicate the verges provide valuable habitat where reproduction takes place. Forests themselves were barriers for almost all target carabids. In the forest clearings, similar amounts of target carabids were encountered in pitfall traps as in the nature reserves and roadside verges, but only teneral individuals of two species were found. In contrast, flying carabids were very abundant in the forest clearings: more than twice as many as in the nature reserves and the roadside verges. This indicates that dispersing carabids in particular make use of these linear forest clearings. We conclude that roadside verges can act as habitat corridors and that linear forest clearings are particularly used as movement corridors. Thus, both offer simple solutions for increasing the connectivity of fragmented landscapes for a threatened insect group.
    Historische veranderingen in de droge stroomdalgraslanden in Nederland: het Medicagini-Avenetum en het Sedo-Thymetum
    Schaffers, A.P. ; Sykora, K.V. ; Huiskes, H.P.J. ; Schaminee, J.H.J. ; Weeda, E.J. - \ 2010
    Stratiotes 40/41 (2010). - ISSN 0928-2297 - p. 27 - 48.
    graslanden - vegetatie - historische ecologie - stroomdalen - flora - grasslands - vegetation - historical ecology - stream valleys
    Er bestond dringend behoefte aan een historisch referentiebeeld van de oorspronkelijke soortensamenstelling en verspeiding van deze graslanden in Nederland. Een dergelijke referentie is een belangrijk hulpmiddel bij de evaluatie en herstellen en ontwikkelingsbeheer en geeft door vergelijking inzicht in de kwaliteit van de huidige stroomdalgraslanden. Wij analyseerden in opdracht van het LNV (kennisnetwerk Ontwikkeling en Beheer Natuurkwaliteit; OBN) een grote verzameling historische vegetatieopnamen van Nederlandse stroomdalgraslanden (Schaffers et al. 2008). In dit artikel behandelen wij de belangrijkste resultaten.
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