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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    Legacies of Amazonian dark earths on forest composition, structure and dynamics
    Quintero Vallejo, E.M. - \ 2015
    Wageningen University. Promotor(en): Frans Bongers; Lourens Poorter, co-promotor(en): Marielos Pena Claros; T. Toledo. - Wageningen : Wageningen University - ISBN 9789462574267 - 168
    bossen - bosgronden - bosdynamiek - bodemvruchtbaarheid - botanische samenstelling - soortensamenstelling - plantengemeenschappen - amazonia - bolivia - forests - forest soils - forest dynamics - soil fertility - botanical composition - species composition - plant communities - amazonia - bolivia
    Summary

    Amazonian forest is seen as the archetype of pristine forests, untouched by humans, but this romantic view is far from reality. In recent years, there is increasing evidence of long and extensive landscape modification by humans. Processes of permanent inhabitation, expansion and retreat of human populations have not always been obvious in those ecosystems, leaving sometimes weak and overlooked imprints in the landscape. An example of one of these inconspicuous alterations are the modifications in the soil known as Amazonian Dark Earths (ADE) or ‘terra preta’ (black earth in Portuguese), which are the product of the accumulation of residuals from permanent or semi-permanent human inhabitation. They are named after the black color of the soils, which is a consequence of the accumulation of charcoal pieces and organic matter in the soil. These soils also contain higher levels of phosphorous, calcium (mainly originated from bone residuals), and nitrogen that increase fertility of the naturally poor soils, thus favouring agricultural practices. Amazonian Dark Earths are distributed in Brazil, Bolivia, Colombia, and Peru, and it is estimated that they could occupy 3% of the area of the Amazon basin.

    With the decrease in human population in the Americas after the encounter with European colonists, sites where ADE had been formed were abandoned and the vegetation recovered. So far, the effects of ADE on old growth forest had not been widely examined and we are just starting to understand the consequences of past human inhabitation on forest composition and structure. In my thesis, I evaluated the effects of ADE on the forest that has re-grown after abandonment by indigenous people in the La Chonta forest, situated at the southern edge of the Amazon basin, in Bolivia. First, I assessed the magnitude of the changes in the soil as a consequence of human occupation. Then, I studied how soil changes affected plant species composition in the forest understory, forest structure and forest dynamics, and finally I determined how seedlings of tree species respond to anthropogenic changes in soil properties.

    Detailed information on soil characteristics and its heterogeneity in the landscape is needed to evaluate the effects of soil on the vegetation. Soil heterogeneity in some sites in the Amazon basin can be increased by the presence of ADE. Therefore, I did detailed soil surveys that allowed me to understand the relationship between past human occupation and alteration in the concentration of soil nutrients. I found that natural soils in the southern Amazonian forest are more fertile than their Central and Eastern Amazon counterparts. Past human presence in the area resulted in soil enrichment, due to increases in the concentration of phosphorus, calcium, potassium, and increases in soil pH. Thus, with this information I could test specific hypothesis about the effects of soil fertility on the vegetation that occurs in these sites.

    In the Amazonian forest in general, soil characteristics influences the composition of understory angiosperm herbs, ferns and palm species. Thus, increases in soil fertility in ADE could affect the distribution of understory angiosperm herbs, ferns and palm species. I evaluated the effect of ADE on composition, richness and abundance of understory species (ferns, angiosperm herbs, and palms). I correlated soil variables associated with ADE, such as Ca, P, and soil pH, with species composition, richness and abundance. I found that the presence of ADE created a gradient in soil nutrients and pH, which changed the composition of understory species, especially of ferns and palms. Additionally, the higher nutrient concentration and the more neutral pH on ADE soils were associated with a decrease in the richness of fern species. I therefore conclude that the current composition of the understory community in La Chonta is a reflection of past human modification of the soil.

    Soil heterogeneity drives forest structure and forest dynamics across the Amazon region, but at a local scale the role of soils on forest dynamics is not well understood. The study of Amazonian Dark Earths (ADE) opens an opportunity to test how increases in soil fertility could affect forest structure and dynamics at local scales. I evaluated the effect of ADE on forest attributes, such standing basal area, tree liana infestation and successional composition, defined by the relative presence of pioneers, to shade tolerant species in the forest. I also evaluated the effect of ADE on individual components of forest dynamics: basal area growth, recruitment, and mortality. Surprisingly, I found that these fertile ADE affected only few forest attributes and components of forest dynamics. Soil pH was one of the edaphic variables that significantly explained forest structure and dynamics. A higher soil pH increased recruitment of intermediate-sized trees (with stem diameter between 20 and 40 cm) and decreased mortality of large trees (stem diameter > 40 cm). The most important effect of pH, however, was on initial basal area and successional composition, which directly affected growth in basal area of intermediate-sized trees.

    Increases in soil nutrients can drive plant responses promoting higher growth rates and lower mortality. Plants respond to soil nutrient availability through a suite of traits, by adjusting their biomass allocation patterns, morphology, tissue chemistry and physiology, which allow them successful establishment and regeneration. The higher amount of nutrients found on ADE compared to natural soils could improve the growth of tropical tree species. I studied the effect of ADE on seedling growth, morphology and physiology in a greenhouse experiment with seedlings of 17 tree species from La Chonta. I found that seedlings did not invest more in roots in non-ADE (to take up scarce soil resources) but they invested in leaves and leaf area in ADE (to enhance light capture), although this did not lead to faster growth rate. Tree species responded differently to an increase in soil Ca concentration, which was 2.4 times higher in ADE than in non-ADE soils. Some species seemed to suffer from Ca toxicity as indicated by higher seedling mortality on ADE; others suffered from nutrient imbalance; whereas other species increased their leaf Ca, P and N concentrations in ADE. Only for this latter group of nutrient accumulators, there was a positive relationship between leaf Ca concentration and the growth rates of seedlings. Contrary to expectations, ADE did not lead to increased seedling growth. The ability of plants to colonize patches of ADE might depend on plant responses to increased soil Ca and their capacity to regulate internal tissue calcium to balance nutrition.

    In summary, in this southern Amazon forest the increased soil nutrient concentrations are a legacy of the humans that inhabited the area. This nutrient addition caused changes in understory species composition and decreased fern species richness and had modest effects on forest structure and dynamics. Increases in nutrients, specifically Ca, can cause positive and negative responses of tree species, resulting in potentially long term effects on the tree species composition of the forest.

    Nutritional status of cattle grazing natural pasture in the Mid Rift Valley grasslands of Ethiopia measured using plant cuticular hydrocarbons and their isotope enrichment
    Bezabih, M. ; Pellikaan, W.F. ; Tolera, A. ; Khan, N.A. ; Hendriks, W.H. - \ 2014
    Livestock Science 161 (2014). - ISSN 1871-1413 - p. 41 - 52.
    n-alkanes - diet selection - compensatory growth - southern ethiopia - mineral status - feed-intake - botanical composition - mammalian herbivores - tropical forages - detergent fiber
    The seasonal diet composition, digestibility and nutrient intake of cattle grazing on natural pasture in the Mid Rift valley region of Ethiopia were determined using an improved n-alkanes method. Sixteen local Borana and Arsi cattle (8 bulls and 8 heifers, 175±10 kg weight) were randomly selected from herds at two sites; a moderately grazed ranch and a heavily grazed, communal grassland area. Grazing behaviour was observed and herbage species consumed sampled during five periods (early-dry, dry, short-rainy, main-rainy and end-of-rainy seasons) throughout the year at the two grazing sites. During each period, animals were dosed twice daily with 152±4 mg of C32 and 150±3 mg C36 alkanes for 10 consecutive days, with faeces samples collected in the morning during the last five days to determine dry matter intake (DMI).The proportion of consumed herbage species in the diet was determined using n-alkanes and their carbon isotope enrichments as markers, while the energy and nutrient intakes were derived from the DMI, digestibility, and diet composition of the DM consumed. Marked seasonal variations (P
    Impact of grazing on range plant community components under arid Mediterranean climate in northern Syria
    Niane, A.A. - \ 2013
    Wageningen University. Promotor(en): Paul Struik, co-promotor(en): Z. Bishaw. - Wageningen : Wageningen UR - ISBN 9789461734143 - 209
    extensieve weiden - begrazing - droge graslanden - rotatiebeweiding - botanische samenstelling - biodiversiteitsbepaling - zaadlevensduur - syrië - rangelands - grazing - arid grasslands - rotational grazing - botanical composition - biodiversity assessment - seed longevity - syria

    Keywords: Rotational grazing, full protection, continuous grazing species richness,

    species diversity, soil seed bank, Bayesian methods, Salsola vermiculata, seed

    longevity, rangeland management, Syria.

    Rangelands represent 70% of the semi-arid and arid Mediterranean land mass. It is a

    natural habitat for millions of people whose livelihood depends on animal husbandry.

    The revolutionary developments in the animal husbandry and veterinary medicines

    resulted in exponential increases in human and livestock population living on and from

    dry lands. To respond to population growth, urbanization and transportation means

    and expanded road networks, land reform and rural development policies forced

    nomads to adopt semi to fully sedentary lifestyles with disintegrated traditional

    community structures and organizational frameworks. Under these demographic

    changes coupled with national and international border crossing restrictions, there was

    an escalation in opportunistic cultivation, and excessive exploitation of the scarce and

    slowly renewable vegetation cover resulting in a steep decline in the primary

    production components of the rangeland ecosystems. In an attempt to stop and reverse

    the degradation process, large-scale re-vegetation programs based on transplanting and

    reseeding with perennial shrubs, resting and grazing management systems were

    devised and implemented. This study aimed to evaluate the impacts of the

    rehabilitation programs on the above-ground vegetation cover and soil seed bank

    replenishment in the Syrian rangelands. The underlying assumption of the

    rehabilitation program is that with a well-established perennial plant cover and proper

    grazing management, top soil is stabilized, soil moisture, nutrients and seed bank are

    replenished, organic matter is accumulated and microorganisms’ activity is promoted

    resulting in greater abundance, species richness and diversity of annuals. To test the

    above hypothesis, field and controlled environment based studies were carried out with

    quantitative data collection and processing on plant species abundance, richness and

    diversity of above-ground vegetation and soil seed bank for fully protected rotationally

    and continuously grazed areas of 10 rangeland sites in northern Syria for three

    consecutive seasons.

    In addition to the use of frequentist statistical approaches for species diversity

    estimation in the studies, the Bayesian method was explored. Moreover, the crucial

    issues of seed quality in re-vegetation were tackled through a study on seed viability

    and longevity in Salsola vermiculata L., which is a highly palatable, well adapted and

    widely used species in the arid Mediterranean rangeland rehabilitation programs.

    The major findings are indicated below.

    Above ground vegetation cover

    The vegetation cover data analysis using ANOVA showed that overall plant density

    consistently declined from full protection to rotational and then continuous grazing in

    9 out of the 10 sites studied, whereas the trends of change in species richness and

    diversity were not consistent.

    Pair-wise comparison showed that plant density, species richness and diversity

    were lowest for the overall plant population under rotational grazing in which plant

    density of perennial grasses was highest. This suggests that rotational grazing has

    reshaped the composition of the plant communities under the study areas by promoting

    the perennial grasses that are more arid rangeland adapted and ecosystem significant.

    Higher plant density under rotational grazing and similarity in species diversity under

    the three grazing treatments for perennial grasses imply that a longer period of

    rehabilitation and/or probably incorporating inter-seasonal rotational grazing and

    variation in herbivore types into the current intra-seasonal rotational grazing system

    will be required to cross the line of no return in plant community composition

    optimization through the prevalent arid Mediterranean rangelands rehabilitation

    programs.

    Soil seed bank assessment

    The soil seed bank data analysis using ANOVA showed no significant differences in

    the overall physical and germinable soil seed bank size and diversity along the grazing

    gradient. However, there was a significant grazing-by-site interaction for both and a

    significant grazing-by-year interaction for germinable seed bank size showing that the

    change in seed bank size is moderated by physical and environmental characteristics

    and human-induced disturbances. Continuous grazing treatments for some sites were

    located near agglomerations of people and animals, main roads and water points.

    Under such conditions the more disturbance-adapted ephemerons and non-palatable

    plants with limited constraints for seed setting dominated and this resulted in a larger

    soil seed bank under continuous compared to rotational and full protection grazing

    treatments. For the more human-induced disturbance distanced sites, the soil seed bank

    was at larger or similar under full and/or rotational compared to continuous grazing.

    Results from pair-wise comparisons showed a simultaneous decline and surge in

    physical and germinable soil seed bank size of annuals and those of perennials under

    the grazing treatments over sites. This suggests relative differences in root competition

    and gap exploitation characteristics among plant functional groups; these differences

    could be considered indicative to rangeland status and a guide to vary herbivores in

    order to maintain optimum plant species diversity in the target rangelands.

    Soil seed banks with no seeds of perennial grasses generated 208 seedlings m-2 of

    germinable soil seed bank under continuous grazing. This is probably due to seed

    setting failure resulting from overgrazing compensated by vegetative reproduction.

    The widely used phanerophytes in the rangeland rehabilitation program had a physical

    soil seed bank of 59.7 to 119 seed m-2 and a zero germinable one. This shows high

    complementarity between physical and germinable seed testing methods for rangeland

    monitoring.

    Similarity indices

    High Morisita-Horn and Sørensen similarities were recorded between the quadrat and

    point intercept measurements of the above ground vegetation and with each of

    physical and germinable soil seed banks. However, the similarity indices of the above

    ground vegetation measurements were higher with the germinable soil seed bank than

    with the physical soil seed bank. This suggests that the germinable soil seed bank is

    more suitable for monitoring arid Mediterranean rangeland than the physical soil seed

    bank.

    Correlation coefficients

    Based on the coefficients of determination (CDs), the variation in plant density and

    seed bank size accounted for a significant portion of the variations in spcies richness

    but not of the diversity indices. However, plant density and species diversity

    consistently and significantly declined during the season with the lowest mean annual

    precipitation showing the crucial role of precipitation in the dynamics of the yet active

    soil seed banks of the study areas. The CDs for the germinable soil seed bank size

    tested under optimum soil moisture with species richness were also significant

    throughout the grazing treatments reflecting the dependence of seed bank dynamics on

    soil moisture.

    For the physical soil seed bank (PSSB), CDs of its size with species richness

    were only significant under rotational grazing implying positive impacts of grazing

    management on soil seed bank replenishment. Morover, the CDs of PSSB richness

    with the diversity indices were only significant for Singletons but not for Shannon and

    Simpson. This is attributable to the fact that the Singleton index is more sensitive to

    rare species than Shannon and Simpson. The non-significant correlations between

    plant density and species diversity reflect a need to incorporate inter-seasonal

    rotational grazing and herbivore variation to the current intra-seasonal rotational

    grazing for greater plant community integrity.

    Phytogeographic analysis

    Using two above and two underground vegetation data collection methods, a total of

    137 species, including 102 annuals and 35 perennials from 36 families of 11

    chorotypes, were recorded. The number of species recorded were 56, 66, 68 and 98

    from physical seed extraction, point intercept, quadrat and grow out test, respectively.

    These results showed the superiority of the growing out test over the three other

    methods. With its easiness and relative flexibility of application in terms of time and

    space, the grow out test seems to be the best method for arid Mediterranean rangelands

    monitoring and assessment of rehabilitation impacts in which the frequency of good

    rainy season is one out of four years.

    Conclusions

     The rotational grazing component of the rangeland rehabilitation program resulted

    in a change in plant community composition shown by an increase in low

    proportional abundance perennial grasses with greater arid Mediterranean

    rangeland adaptation.

     Continuous grazing reduced plant density but not richness and diversity, indicating

    that maximum diversity is not a sign of rangeland health and integrity. This also

    suggests that inter-seasonal rotational grazing and herbivore variation could

    probably improve the shaping effects of grazing on the arid rangeland

    rehabilitation programs.

     Capturing more species and higher similarity indices with the above ground

    measurements, the simple and flexible, germinable soil seed bank test seems to be

    a good monitoring and evaluation method for arid Mediterranean rangelands.

    However, results from the tedious and less accurate physical seed extraction

    method could be crucial to capture the species with long seed dormancy.

     Larger Bayesian estimates of diversity, smaller standard errors, lower p-values and

    more significance of differences in diversity between grazing treatments compared

    to the frequentist approaches were observed, thus indicating clear merits for the

    approach in estimating diversity.

     The seed longevity study showed that under relatively higher seed moisture

    content, longevity increased suggesting that desiccation susceptibility is probably

    the cause of short seed longevity of Salsola vermiculata L. Moreover, drying and

    packaging alone increased longevity, thus providing a simple, cost-effective and

    environmentally friendly method for rangeland rehabilitation programs.

    Stable isotope labeled n-alkanes to assess digesta passage kinetics through the digestive tract of ruminants
    Warner, D. ; Ferreira, L.M.M. ; Breuer, M.J.H. ; Dijkstra, J. ; Pellikaan, W.F. - \ 2013
    PLoS ONE 8 (2013)10. - ISSN 1932-6203 - 9 p.
    marker excretion patterns - carbon-isotope - dairy-cows - enrichments delta-c-13 - botanical composition - particle-size - in-vitro - rumen - herbivores - cattle
    We describe the use of carbon stable isotope (13C) labeled n-alkanes as a potential internal tracer to assess passage kinetics of ingested nutrients in ruminants. Plant cuticular n-alkanes originating from intrinsically 13C labeled ryegrass plants were pulse dosed intraruminally in four rumen-cannulated lactating dairy cows receiving four contrasting ryegrass silage treatments that differed in nitrogen fertilization level (45 or 90 kg nitrogen ha-1) and maturity (early or late). Passage kinetics through the gastrointestinal tract were derived from the d13C (i.e. the ratio 13C:12C) in apparently undigested fecal material. Isotopic enrichment was observed in a wide range of long-chain n-alkanes (C27–C36) and passage kinetics were determined for the most abundant C29, C31 and C33 n-alkanes, for which a sufficiently high response signal was detected by combustion isotope ratio mass spectrometry. Basal diet treatment and carbon chain length of n-alkanes did not affect fractional passage rates from the rumen (K1) among individual n-alkanes (3.71–3.95%/h). Peak concentration time and transit time showed a quantitatively small, significant (p=0.002) increase with carbon chain length. K1 estimates were comparable to those of the 13C labeled digestible dry matter fraction (3.38%/h; r = 0.61 to 0.71; p=0.012). A literature review has shown that n-alkanes are not fermented by microorganisms in the rumen and affirms no preferential depletion of 13C versus 12C. Our results suggest that 13C labeled n-alkanes can be used as nutrient passage tracers and support the reliability of the d13C signature of digestible feed nutrients as a tool to measure nutrient-specific passage kinetics.
    Natuurlijke ontwikkelingen in het Amsterdamse Bos : een studie naar de bosontwikkeling in de Natuurboszone en de Parkboszone
    Verkaik, E. ; Koop, H.G.J.M. ; Clerkx, A.P.P.M. - \ 2010
    Wageningen : Alterra (Alterra-rapport 2102) - 48
    bossen - bosbouw in steden - beschermde bossen - bosstructuur - bosbedrijfsvoering - stedelijke gebieden - natuurontwikkeling - verjonging - botanische samenstelling - amsterdam - noord-holland - forests - urban forestry - reserved forests - forest structure - forest management - urban areas - nature development - regeneration - botanical composition - amsterdam - noord-holland
    De bosontwikkeling in de Noordboszone en Parkboszone van het Amsterdamse bos zijn onderling vergeleken op openheid van het bos, mate van ontmenging van de boomlaag en hoeveelheid dood hout. Beide beheersvormen verschillen onderling in openheid, mate van verjonging, belevingswaarde en boomsoortensamenstelling nu en in de toekomst. De afwisseling van beide beheersvormen geeft een extra meerwaarde aan het bos en zou naast elkaar gehandhaafd moeten worden. Ontmenging of veresdoorning door nietsdoen-beheer treedt nauwelijks op. De waterkwaliteit moet gewaarborgd blijven door afvoeren van blad- en takafval, waarbij voorkomen moet worden dat de oevers worden opgehoogd.
    Flora en vegetatie: samen sterker
    Groenendael, J. van; Schaminee, J.H.J. - \ 2010
    Floron Nieuws 2010 (2010)13. - p. 1 - 12.
    vegetatie - plantenecologische groepen - vegetatiekunde - plantengemeenschappen - botanische samenstelling - biodiversiteit - ecosystemen - databanken - informatiesystemen - vegetation - plant ecological groups - vegetation science - plant communities - botanical composition - biodiversity - ecosystems - databases - information systems
    Artikel over het opnieuw ontmoeten van plantenecologen en vegetatiekundigen. Hierdoor kunnen inzichten en de schaalniveaus uit beide vakgebieden met elkaar verbonden worden. In ecologische studies – en dat geldt zeker voor nietmobiele soorten als planten – is de laatste tijd het belang van ruimtelijke verspreiding van soorten en levensgemeenschappen steeds nadrukkelijker naar voren gekomen, evenals de relatie tussen beiden. De ruimtelijke verspreiding van soorten bepaalt de soortenvoorraad waaruit soorten bij elkaar komen en een lokale (planten)gemeenschap vormen. Dit brengt floristen en vegetatiekundigen bij elkaar. Een tweede verandering is de nadruk die meer recent is komen te liggen op de relatie biodiversiteit en ecosysteemfuncties waarbinnen planten een primaire rol hebben.
    Modelling above-ground herbage mass for a wide range of grassland community types
    Duru, M. ; Adam, M.Y.O. ; Cruz, P. ; Martin, G. ; Ansquer, P. ; Ducourtieux, C. ; Jouany, C. ; Theau, J.P. ; Viegas, J. - \ 2009
    Ecological Modelling 220 (2009)2. - ISSN 0304-3800 - p. 209 - 225.
    permanent pastures - tall fescue - photosynthetic capacity - botanical composition - farming systems - growth analysis - nutritive-value - plant traits - leaf traits - nitrogen
    Whereas it is recognized that management of plant diversity can be the key to reconciling production and environmental aims, most grassland models are tailored for high-value grass species. We proposed to adapt a mono-specific grass model to take into account specific features of species-rich permanent grasslands, especially over the reproductive phase. To this end, we used the concept of plant functional type (PFT), i.e. the grouping of plant species according to plant traits determined by the response of plant species to different management practices (land use and fertilization) and characterizing of agronomic properties of the corresponding species. In the model, weather and nutrient availability act upon rates of biophysical processes (radiation capture and use, plant senescence). These rates are modified over times due to PFT-specific parameters determined experimentally which represent the different strategies of plant species regarding growth. The integration of these parameters into the model made it possible to predict herbage biomass accumulation rate under different management practices for a wide range of plant communities differing in their PFT composition. The model was evaluated in two steps, first by analyzing separately the effects of PFT and an indicator of nutrient availability on herbage accumulation and then by conducting a sensitivity analysis. It was validated using two independent datasets; a cutting experiment running over the whole growing season to examine the consistency of the model outputs under different cutting regimes, and a monitoring of meadows and pastures in spring over a whole growth cycle to assess the model’s ability to reproduce growth curves. Although a good fit was observed between the simulated and observed data, the few discrepancies noticed between field data and predicted values were attributed mainly to the potential presence of non-grass species. More specifically, we noticed that nutrient (mainly nitrogen) availability is the main driver of plant growth rate, and that PFT determines the times at which this rate changes in relation to the phenological characteristics of species present. We concluded that integration of the PFT concept into the initial mono-specific growth model is especially suited to evaluating the consequences of management practices on species-rich permanent grasslands to meet feed production targets
    Vegetation succession as affected by decreasing nitrogen deposition, soil characteristics and site management: A modelling approach
    Wamelink, G.W.W. ; Dobben, H.F. van; Berendse, F. - \ 2009
    Forest Ecology and Management 258 (2009)8. - ISSN 0378-1127 - p. 1762 - 1773.
    organic-matter - seminatural vegetation - phosphorus limitation - botanical composition - heathland ecosystems - plant-populations - salt-marsh - forest - dynamics - competition
    After many years of increasing nitrogen deposition, the deposition rates are now decreasing. A major question is whether this will result in the expected positive effects on plant species diversity. Long-term experiments that investigate the effects of decreasing deposition are not available. Model simulations may yield insight into the possible effects of decreasing nitrogen deposition on the vegetation. Therefore we developed the vegetation succession model SUMO which is closely linked to the soil model SMART2. In SUMO, the biomass development of five functional plant types is simulated as a function of nitrogen availability, light interception and management. The model simulates the change in biomass distribution over functional types during the succession from almost bare soil via grassland or heathland to various forest types. The model was validated on three sites in The Netherlands and one site in the UK. The aboveground biomass of two grassland vegetation types was well simulated, as well as the aboveground biomass of heathlands during succession of sod removal. Some of the stages of forest succession were simulated less well, but the calculated biomass in the older stages agreed with measured values. To explore the long-term effect of a decrease in nitrogen deposition, we applied the model to a heathland and a pine stand. In the heathland a major change was predicted as a result of decreasing nitrogen deposition in combination with turf stripping. The dominance of grasses changed into a dominance of dwarf shrubs, whereas at continuing high levels of nitrogen deposition grasses remained dominant. In contrast, the simulations indicated only very small effects of a decreasing N deposition in pine forests. This difference is due to the removal of excess nitrogen by management (turf stripping) in the heathland, whereas the more extensive management in the forest hardly removes any nitrogen from the system. The main conclusion from these examples is that a decrease of nitrogen deposition may retard succession, and consequently increase biodiversity in heathland but probably not in forest. The effects of declining N deposition depend on the amount of N that is removed from the system as a consequence of the various management regimes. (C) 2009 Elsevier B.V. All rights reserved.
    Species discrimination from a hyperspectral perspective
    Sobhan, I. - \ 2007
    Wageningen University. Promotor(en): Andrew Skidmore; Herbert Prins. - [S.l.] : S.n. - ISBN 9789085048091 - 164
    ecosystemen - vegetatie - bedrijfsvoering - duurzaamheid (sustainability) - soorten - soortendiversiteit - ruimtelijke verdeling - botanische samenstelling - remote sensing - spectraalanalyse - discriminantanalyse - ecosystems - vegetation - management - sustainability - species - species diversity - spatial distribution - botanical composition - remote sensing - spectral analysis - discriminant analysis
    Sustainable management of natural ecosystems requires comprehensive information on species distribution and composition. Remote sensing has the potential to improve the collection of information on species composition. Compared to other vegetation attributes plant species so far remained a difficult attribute to detect with remote sensing. Broad band remote sensing sensors, which have been used extensively for mapping of plant communities, are however not sufficiently sensitive to allow discrimination of individual plant species. The advent of hyperspectral and high spatial resolution sensors offers new opportunities in this respect
    Selectie van relevante grondwaterkarakteristieken voor vegetatietypen ten behoeve van de SBB-catalogus: methodeontwikkeling aan de hand van drie vegetatieklassen
    Delft, S.P.J. van; Hommel, P.W.F.M. ; Waal, R.W. de - \ 2007
    Wageningen : Alterra (Alterra-rapport 1308) - 78
    vegetatietypen - bodemwater - karakteristieken - methodologie - hydrologie - vegetatie - botanische samenstelling - ecohydrologie - vegetation types - soil water - characteristics - methodology - hydrology - vegetation - botanical composition - ecohydrology
    In opdracht van het Ministerie van Landbouw, Natuur en Voedselkwaliteit is een verkenning uitgevoerd naar mogelijke maatregelen om de robuuste verbindingen binnen de Natte As te `ontsnipperen¿ op plaatsen waar deze rijksinfrastructuur (verkeers-, spoor- en vaarwegen) kruisen. Per knelpuntlocatie is bepaald welke principeoplossingen voor ontsnippering mogelijk zijn, in welke mate deze oplossingen de doelen van de betreffende robuuste verbinding realiseren en of er voor het wegnemen van het knelpunt additionele maatregelen in de directe omgeving van de infrastructuur zijn vereist. Per locatie is ook een globale kostenindicatie gegeven. Tevens brengt het onderzoek in beeld wat de te verkiezen volgorde is waarmee de knelpunten binnen de robuuste verbindingen van de Natte As moeten worden aangepakt. Het verschil in ecologisch rendement tussen knelpuntlocaties vormt de basis voor deze prioriteitstelling.
    Dry season diets of sympatric ungulates in lowland Nepal: competition and facilitation in alluvial tall grasslands
    Wegge, P. ; Shrestha, A.K. ; Moe, S.R. - \ 2006
    Ecological Research 21 (2006)5. - ISSN 0912-3814 - p. 698 - 706.
    bardia-wildlife-reserve - one-horned rhinoceros - ecological survey - herbivore diets - microhistological analysis - botanical composition - habitat selection - national-park - mule deer - hog deer
    Based on microhistological analyses of faecal material, we compared the early dry season diets of greater one-horned rhinoceros Rhinoceros unicornis, swamp deer Cervus duvauceli and hog deer Axis porcinus, which inhabit the same alluvial grassland habitat complex in lowland Nepal. Their diets were quite similar, both at the forage category level and within subcategories of graminoids and woody plants. Early successional tall grasses, especially Saccharum spontaneum, were the dominant food of all three species, underlining the key role of the threatened alluvial floodplains in large mammal conservation in South Asia. The two deer species ate significantly more graminoids (>66.5%) than did rhino (45.5%), and although they did not differ in proportions of graminoids, swamp deer ate significantly more late successional tall grasses (Narenga porphyrocoma and Themeda spp.) and short grasses (mainly Imperata cylindrica) than hog deer. The two deer consumed almost equal proportions of woody browse (ca. 10%), significantly less than that of rhino (33.0%). The prediction of the Jarman¿Bell hypothesis, that large-bodied herbivores are less selective and subsist on lower quality graminoids than smaller ruminants, was not supported by the data. Based on this and previous studies in the same area we propose a conceptual model where the larger megaherbivores (rhino and elephant Elephas maximus) facilitate the smaller swamp deer and hog deer during the monsoonal growing season, while the smaller and more selective deer species outcompete the larger during the dry season when food is more limited. Owing to the all-year sprouting ability of S. spontaneum, facilitation may occur also in the dry season with low numbers of megaherbivores, thus accentuating competitive exclusion at higher deer densities.
    Een verkennend onderzoek aan de hand van 92 SBB-referentiepunten : selectie van ecologisch relevante bodemeigenschappen
    Hommel, P.W.F.M. ; Brouwer, E. ; Lucassen, E.C.H.E.T. ; Smolders, A.J.P. ; Waal, R.W. de - \ 2006
    Wageningen : Alterra (Alterra-rapport 1445) - 119
    bodemeigenschappen - bodemchemie - bodemwater - synecologie - vegetatietypen - botanische samenstelling - ecologie - ecohydrologie - soil properties - soil chemistry - soil water - synecology - vegetation types - botanical composition - ecology - ecohydrology
    Het belangrijkste doel van dit onderzoek was te achterhalen welke kenmerken van de bodem en het bodemvocht het meest ‘verklarend’ zijn voor de variatie in soortensamenstelling en vegetatietypen van een set van 92 referentiepunten, beschreven in diverse typen grondwaterafhankelijke, korte vegetaties in Nederland. In het algemeen komen vooral factoren die betrekking hebben op zoutgehalte, zuurgraad en trofiegraad als belangrijk naar voren. Binnen verschillende ecologisch samenhangende groepen vegetatietypen blijken echter steeds andere factoren belangrijk zijn. Een universele benadering voor de bepaling van abiotische randvoorwaarden voor alle vegetatie-eenheden is dus niet te geven. Voorts blijkt dat de meerwaarde van de chemisch analyses ten opzichte alleen de veldkenmerken groot is, de meerwaarde van aanvullende bodemvochtanalyses in het najaar is echter gering
    Large-scale changes in the abundance of common higher plant species across Britain between 1978, 1990 and 1998 as a consequence of human activity: Tests of hypothesised changes in trait representation
    Smart, S.M. ; Bunce, R.G.H. ; Marrs, R. ; LeDuc, M. ; Firbank, L.G. ; Maskell, L.C. ; Scott, W.A. ; Thompson, K. ; Walker, K.J. - \ 2005
    Biological Conservation 124 (2005)3. - ISSN 0006-3207 - p. 355 - 371.
    southern england - functional types - land-use - agricultural intensification - botanical composition - nitrogen deposition - british vegetation - grassland - diversity - biodiversity
    Presence of higher plant species was recorded in 1455 permanently marked quadrats located across Britain in 1978, 1990 and 1998 in a stratified, random sample of 259 1 km squares. Significant increases and decreases in frequency of each species were summarised as changes in the representation of simple traits, each of which had an established relationship with varying levels of fertility or disturbance. By testing the null hypothesis that the trait values represented among increasing or decreasing species were a random draw from the 1978 species pool, we determined the consistency of botanical change with changes in land-use in different vegetation types and landscape locations across Britain. Overall, 63% of significant changes in species occupancy were decreases and 37% increases. Trait changes were largely consistent with the impact of increased nutrient availability across vegetation types associated with inherently low fertility, such as infertile grassland, heath, bog and moorland. Linear habitats in lowland Britain saw trait changes consistent with secondary succession. Although trait changes were highly consistent with eutrophication in upland vegetation, the identity of the changing species left open the possibility that increased N deposition, sheep grazing intensity and local improvement could all have played a part. Recent changes in common plant species across Britain suggest that objectives for large-scale restoration and maintenance of plant communities must address four problems: (a) the increasing scarcity of stress-tolerant species in lowland species pools, (b) exploitation and maintenance of species populations on habitat fragments and linear features in the lowlands, (c) the spread and persistence of generalist species in upland Britain, (d) systemic nutrient enrichment in both lowland and upland environments.
    Milieu-indicatoren op basis van Landelijk Meetnet Flora, Milieu- en Natuurkwaliteit : achtergronddocument bij Natuurbalans 2004
    Veen, M.P. van; Tol, S. van; Esbroek, M.L.P. van; Noordijk, E. ; Knegt, B. de; Hinsberg, A. van - \ 2004
    Wageningen : Natuurplanbureau (Planbureaurapporten 12) - 38
    vegetatie - indicatoren - monitoring - milieueffect - flora - milieubeheer - botanische samenstelling - geschiedenis - nederland - vegetation - indicators - monitoring - environmental impact - flora - environmental management - botanical composition - history - netherlands
    Op basis van het Landelijk Meetnet Flora, Milieu- en Natuurkwaliteit zijn de effecten van milieudruk op de vegetatie aangegeven. Daartoe is langs drie lijnen de indicatiewaarde van de vegetatie onderzocht (i) Hoe verschillen de huidige indicatiewaarden met een historische vergelijking uit de periode 1900-1950?; doel is om de huidige vegetaties en hun indicatiewaarden in context te zetten;(ii) Hoe veranderen de indicatiewaarden van de vegetatie over de huidige stikstofdepositie-gradiënt?, en (iii) Hoe verandert de biomassa van de vegetatielagen over de huidige depositiegradiënt? Uit de ontwikkelde indicatoren blijkt dat in de recente situatie de omvang van de vegetatielagen een gevoelige parameter in relatief voedselarme systemen is. De analyse van veranderingen ten opzichte van een historische situatie laat duidelijke veranderingen in soortsamenstelling zien. In open duinen en op de heide zijn twee trends te zien, ten eerste een toename van soorten van voedselrijkere standplaatsen en ten tweede een toename van soorten met een bredere tolerantie voor zuur. Trefwoorden: Landelijk Meetnet Flora Milieu- en Natuurkwaliteit; historische vergelijking; natuurkwaliteit; milieudruk; stikstofdepositie; Ellenberg-indicatie; biomassa vegetatielagen.
    Gaten in het bosbeheer
    Wijdeven, S.M.J. ; Willems, A.J.H. ; Groot Bruinderink, G.W.T.A. - \ 2004
    Vakblad Natuur Bos Landschap 1 (2004)8. - ISSN 1572-7610 - p. 18 - 19.
    bosbouw - bosbeheer - verjonging - natuurlijke verjonging - velling - kaalslag - geïntegreerde systemen - opstandskenmerken - opstandsstructuur - opstandsontwikkeling - bossen - botanische samenstelling - bosecologie - gaten in het kroondak - soortendiversiteit - biodiversiteit - bosopstanden - geïntegreerd bosbeheer - forestry - forest administration - regeneration - natural regeneration - felling - clear felling - integrated systems - stand characteristics - stand structure - stand development - forests - botanical composition - forest ecology - canopy gaps - species diversity - biodiversity - forest stands - integrated forest management
    Pleidooi voor het toepassen van grotere gaten bij de natuurlijke verjonging van bosopstanden. In de huidige praktijk wordt geïntegreerd bosbeheer veelal ingevuld door kleinschalige ingrepen, afgestemd op het opstandsniveau. Weliswaar verhoogt dit op dit schaalniveau (de plek of de opstand) de variatie, maar het leidt tot een meer uniforme situatie op het niveau van terreindelen en de beheerseenheid. Grote verjongingsgaten hebben niet alleen een specifiek effect op de soortensamenstelling en structuur van de verjonging, maar zijn ook van belang voor andere soorten, zoals kruiden, korstmossen, reptielen, insecten, vogels en grote hoefdieren, en leveren daarmee een bijdrage aan vergroting van de biodiversiteit en de belevingswaarde
    Stand dynamics in Fontainebleau; dynamics in beech forest structure and composition over 17 years in La Tillaie forest reserve, Fontainebleau, France
    Wijdeven, S.M.J. - \ 2004
    Wageningen : Alterra (Alterra-rapport 1124) - 54
    fagus - beschermde bossen - bossen - groei - botanische samenstelling - frankrijk - bosopstanden - fagus - reserved forests - forests - growth - botanical composition - france - forest stands
    Developments in forest structure and composition were studied over a 17 year period in a near-natural beech forests reserve in Fontainebleau, France. In two 1ha plots, all individuals with a dbh > 5cm were mapped, identified and measured in 1983, 1990 and 2000. Individual growth was highly variable between periods, and a large proportion of individuals survived one or both periods with no detectable change in size. Generally, mortality is relatively high. A shift from clumped establishment towards hyperdispersion in large trees was detected. Dead wood levels vary in space and time but are relatively high, compared to other studies. Two regeneration pathways are distinghuised. Firstly, gap phase regeneration, with estblishment in groups and higher survival in dominant individuals. Secondly a substantial proportion of individuals shows strong survival with no detectable change in size and flexible growth patterns. Two major factors are identified in influencing forest development in Fontainebleau. Firstly a dynamic cycle based on forest history, with wave like regeneration waves, slowly leveling of in time. Secondly a shorter storm initiated cycle, creating gaps and opportunities for regeneration and supressed individuals. The combination of forest history, tree behaviour and unpredictable occurences of storms results in complex forest dynamics
    Natuurlijke bosverjonging komt niet zomaar van de grond
    Grimberg, G.T.M. ; Oosterbaan, A. - \ 2003
    Vakblad Natuurbeheer 42 (2003)1. - ISSN 1388-4875 - p. 6 - 9.
    verjonging - natuurlijke verjonging - bossen - bosbeheer - bosbedrijfsvoering - bosbouw - houtteeltkundige systemen - lichten van opstanden - pleksgewijze kap - grondvoorbereiding - grondbewerking - verzorgen van jonge opstanden - bosschade - beweidingsschade - schadepreventie - botanische samenstelling - natuurlijke opstanden - regeneration - natural regeneration - forests - forest administration - forest management - forestry - silvicultural systems - improvement fellings - patch cutting - site preparation - tillage - tending - forest damage - browsing damage - loss prevention - botanical composition - natural stands
    Aan de hand van resultaten van onderzoek en ervaringen van beheerders heeft de contactgroep 'Natuurlijke bosverjonging' maatregelen voor het sturen van de natuurlijke bosverjonging tegen het licht gehouden. Om de verjonging een kans te geven en een goede soortensamenstelling te krijgen kan gedacht worden aan lichting (grootte van het verjongingsgat), bodemvoorbereiding door oppervlakkige grondbewerking (schijveneg), bescherming tegen wildschade (door afrasteringen of het maken van grote verjongingsvlakten), en niet te vroeg ingrijpen in een jong stadium
    Natuurlijke verjonging: van kleine naar grote gaten
    Wijdeven, S.M.J. ; Berg, C.A. van den; Oosterbaan, A. - \ 2003
    Vakblad Natuurbeheer 42 (2003)6. - ISSN 1388-4875 - p. 111 - 115.
    bossen - bosbeheer - bosbedrijfsvoering - natuurlijke verjonging - verjongingsinventarisaties - bosinventarisaties - opstandsstructuur - opstandsontwikkeling - plantensuccessie - botanische samenstelling - bosecologie - gaten in het kroondak - soortendiversiteit - bosopstanden - forests - forest administration - forest management - natural regeneration - regeneration surveys - forest inventories - stand structure - stand development - plant succession - botanical composition - forest ecology - canopy gaps - species diversity - forest stands
    Resultaten van een analyse van de natuurlijke verjonging in relatie tot de gatgrootte op 240 geïnventariseerde verjongingsplekken in naaldbossen op de hoge zandgronden. De grootte van de gaten varieerde van kleine gaten (1 maal de boomhoogte) tot vlakten van 0,5-6 ha (ontstaan na de stormen van de jaren zeventig). Onderzocht werden het stamtal van de verjonging, de aandelen van schaduwtolerante en lichteisende soorten, en de aantallen individuen per soort. Op de grote vlakten is gekeken naar de dichtheid en soortensamenstelling van de verjonging en de aanwezigheid van ruimtelijke patronen. Binnen grote gaten blijkt een grote variatie te zijn in dichtheid en in individuele en groepsgewijze mengingen van verschillende soorten
    Spontane ontwikkeling van bos: gevolgen voor flora en vegetatie
    Bijlsma, R.J. ; Siebel, H.N. - \ 2003
    Vakblad Natuurbeheer 42 (2003)4. - ISSN 1388-4875 - p. 55 - 58.
    bossen - bosbeheer - opstandsontwikkeling - opstandsstructuur - opstandskenmerken - flora - wilde planten - vegetatie - onderlaag - botanische samenstelling - plantensuccessie - plantenecologie - bosecologie - forests - forest administration - stand development - stand structure - stand characteristics - flora - wild plants - vegetation - understorey - botanical composition - plant succession - plant ecology - forest ecology
    In dit eerste artikel in de nieuwe reeks met als thema 'de gevolgen van niets doen voor ...' komt aan de orde welke gevolgen het meer natuurlijke bosbeheer van de laatste decennia heeft voor de bosflora en vegetatie. Voor eikenbossen, beukenbossen en dennenbossen op hogere zandgronden en heuvelland worden de veranderende condities als gevolg van spontane ontwikkeling van de boom- en struiklaag beschreven, en de effecten op vaatplanten en mossen. Er blijken voor Nederland nieuwe bostypen te ontstaan waarvoor geen referenties bestaan; de ontwikkeling van gesloten opgaand bos biedt geen garanties voor het behoud van de bosflora
    Herstel van een bosecosysteem na overbelasting met ammoniak : resultaten van de nul-meting in 2002
    Dueck, T.A. ; Dijk, C.J. van; Leeters, E.E.J.M. ; Groot, G.J. de; Mols, J.J. - \ 2003
    Wageningen : Plant Research International (Nota / Plant Research International 256) - 32
    ecosystemen - bossen - ammoniak - depositie - bosinventarisaties - opstandskenmerken - bodemwater - voedingsstoffen - plantengemeenschappen - botanische samenstelling - nederland - ecosystems - forests - ammonia - deposition - forest inventories - stand characteristics - soil water - nutrients - plant communities - botanical composition - netherlands
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