Moderate livestock grazing of salt, and brackish marshes benefits breeding birds along the mainland coast of the Wadden Sea
Mandema, F.S. ; Tinbergen, J.M. ; Ens, B.J. ; Koffijberg, K. ; Dijkema, K.S. ; Bakker, J.P. - \ 2015
The Wilson Journal of Ornithology 127 (2015)3. - ISSN 1559-4491 - p. 467 - 476.
Our study investigated how bird species richness and abundance was related to livestock grazing on salt, and brackish marshes, with an emphasis on songbirds, and shorebirds. Survey areas with a high percentage cover of tall vegetation were assumed to have experienced lower livestock grazing intensities than survey areas with a low percentage cover of tall vegetation. This relationship was verified for the tall grass Elytrigia atherica. The species richness, and abundance of birds was related to the percentage cover of tall vegetation on the survey areas. We found that total bird species richness was positively related to the percentage cover of tall vegetation. We also found that all of the investigated species, except Pied Avocet (Recurvirostra avosetta), showed a positive relation to the percentage cover of tall vegetation up to a specific percentage of cover. The abundance of investigated songbird species increased up to an intermediate percentage cover of tall vegetation, and decreased at higher percentage cover of tall vegetation, suggesting that moderate grazing of marshes may maximize the abundance of the investigated songbirds. Abundances of Common Redshank (Tringa totanus) and Eurasian Oystercatcher (Haematopus ostralegus) were positively related to the percentage cover of tall vegetation on salt marshes, but negatively related to the percentage cover of tall vegetation on brackish marshes. With intermediate livestock grazing species number, and abundance of most breeding birds can be maintained in coastal marshes. However, specific goals for management should be set before applying a grazing regime to a marsh.
Defoliation and soil compaction jointly drive large-herbivore grazing effects on plants and soil arthropods on clay soil
Klink, R. van; Schrama, M. ; Nolte, S. ; Bakker, J.P. ; Wallis de Vries, M.F. ; Berg, M.P. - \ 2015
Ecosystems 18 (2015)4. - ISSN 1432-9840 - p. 671 - 685.
salt-marsh - nitrogen mineralization - wadden sea - mountain pastures - grassland - collembola - management - diversity - growth - cow
In addition to the well-studied impacts of defecation and defoliation, large herbivores also affect plant and arthropod communities through trampling, and the associated soil compaction. Soil compaction can be expected to be particularly important on wet, fine-textured soils. Therefore, we established a full factorial experiment of defoliation (monthly mowing) and soil compaction (using a rammer, annually) on a clay-rich salt marsh at the Dutch coast, aiming to disentangle the importance of these two factors. Additionally, we compared the effects on soil physical properties, plants, and arthropods to those at a nearby cattle-grazed marsh under dry and under waterlogged conditions. Soil physical conditions of the compacted plots were similar to the conditions at cattle-grazed plots, showing decreased soil aeration and increased waterlogging. Soil salinity was doubled by defoliation and quadrupled by combined defoliation and compaction. Cover of the dominant tall grass Elytrigia atherica was decreased by 80% in the defoliated plots, but cover of halophytes only increased under combined defoliation and compaction. Effects on soil micro-arthropods were most severe under waterlogging, showing a fourfold decrease in abundance and a smaller mean body size under compaction. Although the combined treatment of defoliation and trampling indeed proved most similar to the grazed marsh, large discrepancies remained for both plant and soil fauna communities, presumably because of colonization time lags. We conclude that soil compaction and defoliation differently affect plant and arthropod communities in grazed ecosystems, and that the magnitude of their effects depends on herbivore density, productivity, and soil physical properties.
Do plant traits retrieved from a database accurately predict on-site measurements?
Cordlandwehr, V. ; Meredith, R.L. ; Ozinga, W.A. ; Bekker, R.M. ; Groenendael, J.M. van; Bakker, J.P. - \ 2013
Journal of Ecology 101 (2013)3. - ISSN 0022-0477 - p. 662 - 670.
northwest european flora - life-history traits - land-use change - intraspecific variability - functional diversity - aboveground biomass - relative importance - leaf traits - communities - ecology
1. Trait-based approaches are increasingly used to obtain an insight into the functional aspects of plant communities. Since measuring traits can be time-consuming, large international databases of plant traits are being compiled to share the effort. From these databases, average trait values are often extracted per species by averaging trait values of individuals over multiple populations and habitats. However, the accuracy of such aggregated information from regional databases as a surrogate for on-site measurements has seldom been tested. 2. For the local species pool (aggregated at the habitat-level) and the plant communities on the plots (aggregated at the community-level), we quantified how accurately trait values for each species measured at the plot (plot scale) and those averaged per species and site (site scale) can be estimated from those retrieved from a North-west-European trait database. We analysed three widely used plant traits, canopy height (CH), leaf dry matter content (LDMC) and specific leaf area (SLA), of species occurring in a wet meadow and a salt marsh. 3. Database values more accurately predicted traits aggregated at the habitat-level than those aggregated at the community-level. In addition, traits with lower plasticity, such as LDMC, were more accurately predicted by database values. The performance of database values also depended upon the habitat studied, for example, habitat-level SLA values were accurately predicted by database values in the wet meadow but inaccurately predicted in the salt marsh. 4. Synthesis. This study reveals that the accuracy of traits retrieved from a database depends on the level of aggregation (lower at community-level), the trait (lower in plastic traits) and the habitat type (lower in extreme habitats). For studies focussing on processes mainly acting at the site scale (e.g. trait–environment relationships), traits retrieved from a regional database and filtered according to habitat will probably lead to good results. Whereas studying processes acting at the plot scale (e.g. niche partitioning), requires the additional effort of measuring traits on-site.
|Database means compared to on-site measurement of traits
Cordlandwehr, V. ; Ozinga, W.A. ; Bekker, R.M. ; Bakker, J.P. - \ 2013
In: Proceedings of 56th Symposium of the International Association for Vegetation Science, 26–30 June 2013 Tartu Estonia. - - p. 37 - 37.
In functional ecology trait-based approaches are widely used. Gathering on-site measurements of traits can be very laborious, therefore, using traits retrieved from regional or global databases as proxies appears a convenient solution. However, many traits show intraspecific variability in trait values. Thus, using species mean trait values might lead to skewed patterns in traits and by that misinterpretations. The extent to which this is a problem probably depends on geographic scale, level of trait aggregation, type of process and habitat type. If we knew when it would be possible to use mean trait values of species from regional or global databases as an accurate proxy for on-site trait values of individuals, local-level experiments could be conducted without the often laborious task of measuring the functional traits of individual plants for each sampled community. Using data from two grassland sites, a salt marsh and a wet hay-meadow, we analysed the effect of species mean trait values retrieved from a regional database on the resulting trait structure of our plant communities. We compared on-site measurements from a 2 × 2 m scale with species mean traits aggregated per site (i.e. the habitat species pool), and those retrieved from a regional database (the LEDA trait database). We focused on the commonly used morphological plant traits canopy height, specific leaf area, and leaf dry matter content. Our results show that database values are more accurate in predicting the trait values in the habitat species pool as compared to the community mean traits aggregated per 2 × 2 m plots. The performance of database values also depends upon the trait and habitat type considered, as we show that traits with a high plasticity and traits in stressful habitats are being less accurately predicted. We can also explain why species trait means generally show a skewed representation of community traits as not only species composition, but also the individuals within species influence the community means. For studies focussing on processes mainly acting at the site scale (e.g. trait-environment relationships) traits retrieved from a regional database and filtered according to habitat will probably lead to reliable results. In contrast, studies focussing on processes acting at the plot scale (e.g. niche partitioning), require the additional effort of measuring traits on-site.
Grazed vegetation mosaics do not maximize arthropod diversity: Evidence from salt marshes
Klink, R. van; Rickert, C. ; Vermeulen, R. ; Vorst, O. ; Wallis de Vries, M.F. ; Bakker, J.P. - \ 2013
Biological Conservation 164 (2013). - ISSN 0006-3207 - p. 150 - 157.
Light to moderate grazing in grasslands can create vegetation mosaics of short grazed vegetation and tall ungrazed vegetation. These mosaics have been proposed to maximize plant and animal species richness, yet experimental evidence, especially regarding arthropods is scarce. This study compares abundance, richness and species composition of arthropods in grazed mosaics to those of homogeneous short and tall vegetation. We sampled arthropods on three German coastal salt marshes where grazing with three densities (high, moderate and none) was installed in 1989 on previously intensively grazed plots. Stable vegetation mosaics had developed under moderate stocking densities. We collected spiders, beetles, bugs and moth larvae by suction sampling in a stratified random sampling design. Treatments had caused large differences in plant composition after 20 years, which were reflected in the arthropod community. Most species showed a clear preference for either short or tall vegetation, but some species were most abundant in grazed mosaics. Arthropod richness and composition were similar in patches of short vegetation in moderately and highly stocked plots, while patches of tall vegetation were similar to ungrazed plots. Surprisingly, however, grazed mosaics were not richer in species than homogeneous tall vegetation, despite the co-occurrence of species from short, tall and mosaic vegetation. We conclude that, although arthropod richness of salt marshes is greatly enhanced when stocking density is decreased, this cannot substitute ungrazed marshes for conservation of arthropod diversity. However, long term cessation leads to the disappearance of several species, and therefore the possibilities of rotational grazing should be explored.
Measuring sedimentation in tidal marshes: a review on methods and their applicability in biogeomorphological studies
Nolte, S. ; Koppenaal, E.C. ; Esselink, P. ; Dijkema, K.S. ; Schuerch, M. ; Groot, A.V. de; Bakker, J.P. ; Temmerman, S. - \ 2013
Journal of Coastal Conservation 17 (2013)3. - ISSN 1400-0350 - p. 301 - 325.
sea-level rise - fallout pb-210 measurements - high-precision measurements - regenerative-dose protocol - rapidly subsiding wetland - barrier salt-marsh - san-francisco bay - fresh-water - ecosystem engineers - accumulation rates
It is increasingly recognised that interactions between geomorphological and biotic processes control the functioning of many ecosystem types as described e.g. by the ecological theory of ecosystem engineering. Consequently, the need for specific bio-geomorphological research methods is growing recently. Much research on bio-geomorphological processes is done in coastal marshes. These areas provide clear examples of ecosystem engineering as well as other bio-geomorphological processes: Marsh vegetation slows down tidal currents and hence stimulates the process of sedimentation, while vice versa, the sedimentation controls ecological processes like vegetation succession. This review is meant to give insights in the various available methods to measure sedimentation, with special attention to their suitability to quantify bio-geomorphological interactions. The choice of method used to measure sedimentation is important to obtain the correct parameters to understand the biogeomorphology of tidal salt marshes. This review, therefore, aims to be a tool for decision making regarding the processes to be measured and the methods to be used. We, subdivide the methods into those measuring suspended sediment concentration (A), sediment deposition (B), accretion (C) and surface-elevation change (D). With this review, we would like to further encourage interdisciplinary studies in the fields of ecology and geomorphology.
Spatio-temporal dynamics of the invasive plant species Elytrigia atherica on natural salt marshes
Veeneklaas, R.M. ; Dijkema, K.S. ; Hecker, N. ; Bakker, J.P. - \ 2013
Applied Vegetation Science 16 (2013)2. - ISSN 1402-2001 - p. 205 - 216.
sea-level rise - long-term - vegetation changes - elymus-athericus - tidal marshes - wadden sea - deposition - gradient - impact - opportunities
Question In the past decades, the tall native invasive grass, Elytrigia atherica, has been increasing in frequency and dominance on salt marshes along the Wadden Sea coast. Is this rapid expansion an outcome of natural succession or is it driven by anthropogenic eutrophication resulting from atmospheric deposition? Location Salt marshes on four back-barrier islands, Wadden Sea on the coast of the Netherlands and Germany. Methods We used a combination of time series of vegetation maps and chronosequence data of four naturally developed salt marshes to address our questions. These salt marshes have not been grazed by livestock or subject to other management regimes. By comparing development within and between four different salt marshes, we were able to study the spatial and temporal dynamics of the community dominated by E. atherica on natural salt marshes. Results The expansion rate of the E. atherica community was highest on young salt marshes (up to 30yr old) with vertical accretion rates of 0.35cm center dot yr1. The rate of expansion decreased on older marshes and the direction reversed, becoming negative, on the oldest marshes (around 90yr old), which have no vertical accretion and are under waterlogged conditions. Conclusions The expansion of E. atherica on natural, back-barrier islands along the Wadden Sea coast is more influenced by the age of the salt marsh and patterns in vertical accretion of soil than by uniformly spread atmospheric deposition.
Long-term effects of scrub clearance and litter removal on the re-establishment of dry alvar grassland species
Bakker, J.P. ; Rosén, E. ; Ozinga, W.A. ; Bretfeld, M. ; Feldt, T. ; Stahl, J. - \ 2012
Annales Botanici Fennici 49 (2012)1-2. - ISSN 0003-3847 - p. 21 - 30.
northwest european flora - life-history traits - chalk grassland - seedling recruitment - limestone grassland - plant-communities - bryophyte layer - establishment - dispersal - emergence
Many characteristic dry alvar grassland species disappear after cessation of livestock grazing as a result of encroachment by Juniperus communis. We studied the re-establishment of these species after scrub clearance with and without the removal of the layer of litter and mosses in long-term (14 years) permanent plots. Most of the species belonging to the community species pool of dry alvar grassland species before clearance were found in permanent plots between 2 and 14 years after the clearance. A large part originated from vegetative spread of already occurring species in the established vegetation in the surroundings. Only a small part of the long-term persistent soil seed bank resulted in the re-establishment of alvar species. There was no significant difference in the traits soil seed bank, seed weight and long-distance dispersal by wind, dung or fur of animals of established and non-established species. Removal of litter and mosses positively affected the re-establishment of alvar species
Biodiversiteit nu en in de toekomst
Bakker, J.P. ; Duel, H. ; Zouwen, M.W. van der - \ 2012
Landschap : tijdschrift voor landschapsecologie en milieukunde 25 (2012)3. - ISSN 0169-6300 - p. 174 - 178.
biodiversiteit - natuurbescherming - ecologie - functionele biodiversiteit - wetenschappelijk onderzoek - biodiversity - nature conservation - ecology - functional biodiversity - scientific research
Dit afsluitende artikel (binnen een themanummer) geeft aanknopingspunten voor de beleids- en beheerpraktijk die voortvloeien uit het stimuleringsprogramma biodiversiteit NWO. De conclusies zijn geclusterd rond vier aspecten van biodiversiteit: veranderingen in ruimte, tijd en databeheer; functionaliteit; de strijd om ruimte; maatschappelijke inpassing. Het programma heeft geresulteerd in 17 proefschriften en ruim 80 artikelen; gekozen is voor disciplines, waarin Nederland voorop loopt (functionele biodiversiteit, dispersie van soorten en natuurbeheer en natuurherstel)
|Mechanisms involved in salt-marsh rejuvenation
Bakker, J.P. ; Bouma, T.J. ; Groot, A.V. de; Meijer, R.J. de; Herman, P.M.J. ; Koppel, J. van de; Graaf, E.R. van der; Wesenbeeck, B.K. van - \ 2011
Geesthacht, Germany : Zentrum für Material- und Küstenforschung GmbH - 12 p.
Spatial patterns in accretion on barrier-island salt marshes
Groot, A.V. de; Veeneklaas, R.M. ; Kuijper, D.P.J. ; Bakker, J.P. - \ 2011
Geomorphology 134 (2011)3-4. - ISSN 0169-555X - p. 280 - 296.
sea-level rise - vegetation succession - sediment deposition - tidal marshes - elevation - norfolk - surface - europe - uk - restoration
On minerogenic barrier-island salt marshes, sedimentation is spatially heterogeneous. Although the main forcing factors for sedimentation are known, much less is known about the characteristic sizes of this spatial patterning. Such patterning gives information on the spatial component of salt-marsh formation and on the uncertainty in measured accretion rates. We used variograms (geostatistics) to study the size of spatial patterns in the thickness of salt-marsh deposits, based on a database of over 10,000 soil cores. These were taken at various spatial scales ranging from metres to kilometres, along a chronosequence representing 10–150 years of salt-marsh formation at three barrier islands in the Wadden Sea (south-eastern North Sea). The general complexity of salt-marsh accretion was reflected in the observed patterns of the thickness of the marsh deposits. The patterns were nested and ranged in horizontal size from 3 m on sites with micro-topography, to 900 m at the scale of the entire marsh. Their structure and size changed with salt-marsh age and there was no characteristic pattern size. Although the pre-marsh topography is an important large-scale control, during salt-marsh development independent spatial patterns are superimposed. When scaling up data on salt-marsh sedimentation, the presence of spatial patterning adds uncertainty to the prediction. The consequence of the complexity of these patterns is that the spatial uncertainty is a (not necessarily linear) function of the area under consideration, which can only be quantified if it is explicitly measured. Our findings therefore pose a cautionary note to studies of salt-marsh resilience to sea-level rise: reliable estimates can only be derived if they are based on measurements that take into account the entire salt marsh
Sand in the salt marsh: Contribution of high-energy conditions to salt-marsh accretion
Groot, A.V. de; Veeneklaas, R.M. ; Bakker, J.P. - \ 2011
Marine Geology 282 (2011)3-4. - ISSN 0025-3227 - p. 240 - 254.
sea-level rise - southern north-sea - danish wadden sea - tidal marsh - storm deposits - vegetation - succession - england - morphodynamics - sedimentation
The environmental dynamics at barrier-island salt marshes are reflected in lateral and vertical textural patterns of the marsh sediment. During normal conditions, fine-grained sediment is deposited, whereas during high-energy conditions also sand accretion can occur. This paper describes the occurrence and importance of sand deposits for the building of salt marshes. The study was carried out in the Wadden Sea on the islands of Schiermonnikoog (NL), Terschelling (NL) and the peninsula of Skallingen (DK). Firstly, we recorded the presence of sand in the sediment representing initial salt-marsh formation. The results indicate that part of the salt marsh developed under conditions that were dynamically enough for sand to be transported. The spatial distribution of these conditions depends on soil elevation and location on the marsh, modified by the presence of artificial sand dikes. Further we recorded the presence and thickness of sand layers within the salt-marsh sediment. Sand layers are found on twenty percent of the marsh area and are partly associated with the local sources of the sand, i.e. marsh creeks, the salt-marsh edge and washovers. In total, sand layers contribute less than ten percent to the volume of marsh deposits on Schiermonnikoog. We dated the layers using the thickness of the deposits and known marsh age. The ages of the layers indicate that for the decadal occurrence of storms capable of depositing sand in the salt marsh, the local hydrodynamics and availability of sand determine whether a site receives sand or not. © 2011
|Dispersal failure contributes to plant losses in NW Europe
Ozinga, W.A. ; Bekker, R.M. ; Bakker, J.P. - \ 2011
In: CEES Progress report 2009 / Nunnink, J., Plenter-Hartman, E., Groningen : CEES, University of Groningen - p. 64 - 66.
How species traits and affinity to urban land use control large-scale species frequency
Knapp, S. ; Kuhn, I. ; Bakker, J.P. ; Kleyer, M. ; Klotz, S. ; Ozinga, W.A. ; Poschlod, P. ; Thompson, K. ; Thuiller, W. ; Romermann, C. - \ 2009
Diversity and Distributions 15 (2009)3. - ISSN 1366-9516 - p. 533 - 546.
life-history traits - indicator values - spatial autocorrelation - plant ecology - models - patterns - europe - areas - flora - biodiversity
Although urban areas only occupy c. 2.8% of the earth's land surface, urbanization threatens biodiversity as areas of high human population density often coincide with high biodiversity. Therefore, nature conservation should concentrate on both remote areas and densely populated regions. Protecting rare plant species in rural and urban areas can contribute to the protection of biodiversity. We therefore need to understand why species are rare. Studies on causes of rarity often concentrate on either plant traits or extrinsic threats (such as habitat fragmentation or nitrogen enrichment). However, there are only a few studies that combine traits and extrinsic threats, although such analyses might clarify causes of rarity. We assessed how the affinity of vascular plant species to urban land use ('urbanity') interacts with plant traits in determining species frequency. Germany, resolution c. 12 km x 11 km. Species with a low frequency may be rare because they occur in rare habitats or because of other reasons, although their habitat is frequent. Therefore, we calculated the frequency of species corrected for habitat frequency, i.e. relative species frequency. We explained relative species frequency by the interactions of species traits and species affinity to urban land use using generalized linear models. Simultaneous autoregressive error models controlled for phylogenetic relationships of species. Relative species frequency depends on species affinity to urban land use, independent of the different interactions between traits and urbanity used as predictors. The higher the urbanity the higher is species frequency. Urbanity interacts with species preferences towards temperature and soil acidity. Moreover, dispersal, nitrogen preferences and origin explain relative species frequency, amongst others. Many rare species, especially those preferring cool or acidic habitats might already have disappeared from urban areas. Analyses that combine species traits and environmental effects can explain the causes of rarity and help to derive better conservation strategies.
Dispersal failure contributes to plant losses in NW Europe
Ozinga, W.A. ; Römermann, C. ; Bekker, R.M. ; Prinzing, A. ; Tamis, W.L.M. ; Schaminée, J.H.J. ; Hennekens, S.M. ; Thompson, K. ; Poschlod, P. ; Kleyer, M. ; Bakker, J.P. ; Groenendael, J.M. van - \ 2009
Ecology Letters 12 (2009)1. - ISSN 1461-023X - p. 66 - 74.
vegetatietypen - dispersie - plantengemeenschappen - noordwest-europa - vegetation types - dispersion - plant communities - northwestern europe - life-history traits - species richness - environmental-conditions - conservation - diversity - communities - extinction - landscape - ecology - fragmentation
The ongoing decline of many plant species in Northwest Europe indicates that traditional conservation measures to improve the habitat quality, although useful, are not enough to halt diversity losses. Using recent databases, we show for the first time that differences between species in adaptations to various dispersal vectors, in combination with changes in the availability of these vectors, contribute significantly to explaining losses in plant diversity in Northwest Europe in the 20th century. Species with water- or fur-assisted dispersal are over-represented among declining species, while others (wind- or bird-assisted dispersal) are under-represented. Our analysis indicates that the 'colonization deficit' due to a degraded dispersal infrastructure is no less important in explaining plant diversity losses than the more commonly accepted effect of eutrophication and associated niche-based processes. Our findings call for measures that aim to restore the dispersal infrastructure across entire regions and that go beyond current conservation practices
Unpreferred plants affect patch choice and spatial distribution of European brown hares
Kuijper, D.P.J. ; Bakker, J.P. - \ 2008
Acta Oecologica-International Journal of Ecology 34 (2008)3. - ISSN 1146-609X - p. 339 - 344.
salt-marsh - vegetation succession - productivity gradient - foraging efficiency - lepus-europaeus - barnacle geese - herbivory - facilitation - competition - population
Many herbivore species prefer to forage on patches of intermediate biomass. Plant quality and forage efficiency are predicted to decrease with increasing plant standing crop which explains the lower preference of the herbivore. However, often is ignored that on the long-term, plant species composition is predicted to change with increasing plant standing crop. The amount of low-quality, unpreferred food plants increases with increasing plant standing crop. In the present study the effects of unpreferred plants on patch choice and distribution of European brown hare in a salt-marsh system were studied. In one experiment, unpreferred plants were removed from plots. In the second experiment, plots were planted with different densities of an unpreferred artificial plant. Removal of unpreferred plants increased hare-grazing pressure more than fivefold compared to unmanipulated plots. Planting of unpreferred plants reduced hare-grazing pressure, with a significant reduction of grazing already occurring at low unpreferred plant density. Spatial distribution of hares within this salt-marsh system was related to spatial arrangement of unpreferred plants. Hare-grazing intensity decreased strongly with increasing abundance of unpreferred plants despite a high abundance of principal food plants. The results of this study indicate that plant species replacement is an important factor determining patch choice and spatial distribution of hares next to changing plant quality. Increasing abundance of unpreferred plant species can strengthen the decreasing patch quality with increasing standing crop and can decrease grazing intensity when preferred food plants are still abundantly present.
The LEDA Traitbase: a database of life-history traits of the Northwest European flora
Kleyer, M. ; Bekker, R.M. ; Knevel, I.C. ; Bakker, J.P. ; Thompson, K. ; Sonnenschein, M. ; Poschlod, P. ; Groenendael, J.M. van; Klimes, L. ; Klimesova, J. ; Klotz, S. ; Rusch, G.M. ; Hermy, M. ; Adriaens, D. ; Boedeltje, G. ; Bossuyt, B. ; Dannemann, A. ; Endels, P. ; Götzenberger, L. ; Hodgson, J.G. ; Jackel, A.K. ; Kühn, L. ; Kunzmann, D. ; Ozinga, W.A. ; Römermann, C. ; Stadler, M. ; Schlegelmilch, J. ; Steendam, H.J. ; Tackenberg, O. ; Wilmann, B. ; Cornelissen, J.H.C. ; Eriksson, O. ; Garnier, E. ; Peco, B. - \ 2008
Journal of Ecology 96 (2008). - ISSN 0022-0477 - p. 1266 - 1274.
plant functional traits - trade-off - communities - dispersal - mechanisms - consequences - regeneration - biodiversity - divergence - attributes
An international group of scientists has built an open internet data base of life-history traits of the Northwest European flora (the LEDA-Traitbase) that can be used as a data source for fundamental research on plant biodiversity and coexistence, macro-ecological patterns and plant functional responses. The species-trait matrix comprises referenced information under the control of an editorial board, for ca. 3000 species of the Northwest European flora, combining existing information and additional measurements. The data base currently contains data on 26 plant traits that describe three key features of plant dynamics: persistence, regeneration and dispersal. The LEDA-Traitbase is freely available at http://www.leda-traitbase.org. We present the structure of the data base and an overview of the trait information available. Synthesis. The LEDA Traitbase is useful for large-scale analyses of functional responses of communities to environmental change, effects of community trait composition on ecosystem properties and patterns of rarity and invasiveness, as well as linkages between traits as expressions of fundamental trade-offs in plants.
Time-scale effects in the interaction between a large and a small herbivore
Kuijper, D.P.J. ; Beek, P. ; Wieren, S.E. van; Bakker, J.P. - \ 2008
Basic and Applied Ecology 9 (2008)2. - ISSN 1439-1791 - p. 126 - 134.
hares lepus-europaeus - brown hares - salt-marsh - barnacle geese - mountain hares - competition - succession - facilitation - communities - management
In the short term, grazing will mainly affect plant biomass and forage quality. However, grazing can affect plant species composition by accelerating or retarding succession at longer time-scales. Few studies concerning interactions among herbivores have taken the change in plant species composition into account. In a salt-marsh system, the long-term effects of exclusion of a large herbivore (cattle) on the abundance of a small herbivore (hare) were studied. Excluding cattle grazing for 30 years resulted in large changes in vegetation composition. In general, the cover of tall-growing species increased in the absence of cattle grazing. These long-term changes negatively affected hare grazing intensity. Hares preferentially fed on Festuca rubra and negatively selected tall growing plants, such as Elymus athericus, both in cattle-grazed and long-term ungrazed areas. However, the intensity of hare grazing was not related to the cover of F. rubra. The cover of tall-growing plants (E. athericus, Atriplex prostrata and Juncus maritimus) appeared to be the best predictor and hare grazing intensity decreased sharply with an increase of the cover of tall plants. When cover of tall plants did not increase, hare grazing intensity was not affected. The study shows that the time-scale of the experiment is of prime importance in studying interactions between herbivores. Species that do not seem to influence the abundance of one another or are competing for the same resources on a short time-scale might well be facilitating each other when looking at larger time-scales while taking plant species replacement into account.
|The impact of browsing and grazing herbivores on biodiversity
Wieren, S.E. van; Bakker, J.P. - \ 2008
In: The ecology of browsing and grazing / Gordon, I.J., Prins, H.H.T., Berlin : Springer (Ecological Studies 195) - ISBN 9783540724216 - p. 263 - 292.
|Plant trait attributes of the resident community and local soil conditions as predictors for the occurrence of species of the Calthion palustris alliance
Cordlandwehr, V. ; Boom, B.W.A.F.H. van den; Ozinga, W.A. ; Bekker, R.M. ; Bakker, J.P. - \ 2007
In: Book of abstracts of the 50th Annual Symposium Cultural Landscapes - Changing landscapes, Swansea, Wales, UK, 23 - 27 July, 2007 Swansea, Wales : International Association for Vegetation Science - p. 12 - 13.