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(1 - 12 of 12)
Biogeomorphological aspects of a model barrier island and its surroundings
Bakker, J.P.; Berg, M.P.; Grootjans, A.P.; Olff, H.; Schrama, M.J.J.; Reijers, V.C.; Heide, T. van der 2023
Biogeomorphological aspects of a model barrier island and its surroundings: interactions between abiotic conditions and biota shaping the tidal and terrestrial landscape: A synthesis
Article / Letter to editor
open access
Barrier islands occur in north-western Europe between the North Sea and the Wadden Sea along the coast of Denmark, Germany and the Netherlands. Geomorphological units such as dunes and salt marshes... Show moreBarrier islands occur in north-western Europe between the North Sea and the Wadden Sea along the coast of Denmark, Germany and the Netherlands. Geomorphological units such as dunes and salt marshes are built by wind, water and sediment. The biota also feed back to the units by trapping sand and silt, transported by water and wind thus (de)stabilizing the local substrate and are able to modify their own abiotic environment. Hence, we refer to them as biogeomorphological units, thus including the role of engineering biota. We consider seven units: tidal basin, island head, intertidal flats, dune arc complex, wash-over complex, island tail with salt marsh, and green beach. We focus on the well-studied West-Frisian island of Schiermonnikoog, the Netherlands, from which we integrated published data. The biogeomorphological units are built with bioengineering species, and in turn provide habitats for plant- and animal species. These communities are subject to succession until climax stages with various timescales. These temporal aspects are derived from long-term measurements in the field, including the study of chronosequences. Biogeomorphological units also affect each other, including feed-backs from animals, plants and micro-organisms. Based on that we present a conceptual model of this particular barrier island. Knowledge gaps that can be identified include 1) interactions among geomorphological units, 2) interactions among these units and bio-engineers to come to biogeomorphological units, and 3) multiple spatial-temporal scales. Human interference such as Aatmospheric deposition applies to all islands and is difficult to manage. Other human interferences may, however, differ among individual islands and their surroundings. They can be managed such as various intensities of fisheries, sand suppletion, extraction of groundwater, the attitude of local people towards artificial sand-drift dikes and livestock grazing. Show less
The metamicrobiome
Jonge, I.K. de; Veldhuis, M.P.; Cornelissen, J.H.C.; Berg, M.P.; Olff, H. 2023
The metamicrobiome: key determinant of the homeostasis of nutrient recycling
Article / Letter to editor
open access
2023-08-02T00:00:00Z
Spatiotemporal habitat use of large African herbivores across a conservation border
Jong, I.K. de; Olff, H.; Wormmeester, R.; Veldhuis, M.P. 2022
Spatiotemporal habitat use of large African herbivores across a conservation border
Article / Letter to editor
open access
Explanations for nitrogen decline
Olff, H.; Aerts, R.; Bobbink, R.; Cornelissen, J.H.C.; Erisman, J.W.; Galloway, J.N.; ... ; Wardle, D.A. 2022
Explanations for nitrogen decline
Article / Letter to editor
open access
Camera traps enable the estimation of herbaceous aboveground net primary production (ANPP) in an African savanna at high temporal resolution
Jonge, I.K. de; Veldhuis, M.P.; Vrieling, A.; Olff, H. 2022
Camera traps enable the estimation of herbaceous aboveground net primary production (ANPP) in an African savanna at high temporal resolution
Article / Letter to editor
open access
Upstream land-use negatively affects river flow dynamics in the Serengeti National Park
Kihwele, E.S.; Veldhuis, M.P.; Loishooki, A.; Hongoa, J.R.; Hopcraft, J.G.C.; Olff, H.; Wolanski, E. 2021
Upstream land-use negatively affects river flow dynamics in the Serengeti National Park
Article / Letter to editor
open access
In the Greater Serengeti-Mara ecosystem, with the Serengeti National Park (SNP) at its core, people and wildlife are strongly dependent on water supply that has a strong seasonal and inter-annual... Show moreIn the Greater Serengeti-Mara ecosystem, with the Serengeti National Park (SNP) at its core, people and wildlife are strongly dependent on water supply that has a strong seasonal and inter-annual variability. The Mara River, the only perennial river in SNP, and a number of small streams originate from outside SNP before flowing through it. In those watersheds increasing grazing pressure from livestock, deforestation, irrigation and other land uses affect river flows in SNP that subsequently have impacts on wildlife. We quantified the changes since the 1970s of river discharge dynamics. We found that the baseflow recession period for the Mbalageti River has remained unchanged at 70 days, which is a natural system inside SNP. By contrast it has decreased from 100 days in the 1970s to 16 days at present for the Mara River, coinciding with increased commercial-scale irrigation in Kenya that extract Mara River water before it reaches SNP. This irrigation will result in zero flow in the river in SNP if the proposed dams in the river in Kenya are built. We observed high flash floods and prolonged periods of zero flows in streams draining livestock grazed watersheds, where severe major erosion prevails that results in gully formation. This eroded sediment is expected to silt and dry out the scattered dry season water holes in SNP, which are an important source of drinkable water for wildlife during the dry season. It appears likely that the future water supply of SNP is at risk, and this has major consequences for its people and wildlife. Ecohydrology-based solutions at the catchment scale are urgently needed to reduce catchment degradation while ensuring sustainable water provision. Show less
Large herbivore assemblages in a changing climate: incorporating water dependence and thermoregulation
Veldhuis, M.P.; Kihwele, E.S.; Cromsigt, J.P.G.M.; Ogutu, J.O.; Hoperaft, J.G.C.; Owen-Smith, N.; Olff, H. 2019
Large herbivore assemblages in a changing climate: incorporating water dependence and thermoregulation
Article / Letter to editor
open access
The coexistence of different species of large herbivores (ungulates) in grasslands and savannas has fascinated ecologists for decades. However, changes in climate, land‐use and trophic structure of... Show moreThe coexistence of different species of large herbivores (ungulates) in grasslands and savannas has fascinated ecologists for decades. However, changes in climate, land‐use and trophic structure of ecosystems increasingly jeopardise the persistence of such diverse assemblages. Body size has been used successfully to explain ungulate niche differentiation with regard to food requirements and predation sensitivity. But this single trait axis insufficiently captures interspecific differences in water requirements and thermoregulatory capacity and thus sensitivity to climate change. Here, we develop a two‐dimensional trait space of body size and minimum dung moisture content that characterises the combined food and water requirements of large herbivores. From this, we predict that increased spatial homogeneity in water availability in drylands reduces the number of ungulate species that will coexist. But we also predict that extreme droughts will cause the larger, water‐dependent grazers as wildebeest, zebra and buffalo–dominant species in savanna ecosystems – to be replaced by smaller, less water‐dependent species. Subsequently, we explore how other constraints such as predation risk and thermoregulation are connected to this two‐dimensional framework. Our novel framework integrates multiple simultaneous stressors for herbivores and yields an extensive set of testable hypotheses about the expected changes in large herbivore community composition following climate change. Show less
Conservation: Beyond population growth Response
Ogutu, J.O.; Veldhuis, M.P.; Morrison, T.A.; Hopcraft, J.G.C.; Olff, H. 2019
Conservation: Beyond population growth Response
Article / Letter to editor
open access
Cross-boundary human impacts compromise the Serengeti-Mara ecosystem
Veldhuis, M.P.; Ritchie, M.E.; Ogutu, J.O.; Morrison, T.A.; Beale, C.M.; Estes, A.B.; ... ; Olff, H. 2019
Cross-boundary human impacts compromise the Serengeti-Mara ecosystem
Article / Letter to editor
open access
Decoupled diversity dynamics in green and brown webs during primary succession in a saltmarsh
Schrama, M.J.J.; Plas, F. van der; Berg, M.P.; Olff, H. 2016
Decoupled diversity dynamics in green and brown webs during primary succession in a saltmarsh
Article / Letter to editor
open access
2017-11-17T00:00:00Z
  1. Terrestrial ecosystems are characterized by a strong functional connection between the green (plant–herbivore‐based) and brown (detritus–detritivore‐based) parts of the food web, which both develop...

Show more
  1. Terrestrial ecosystems are characterized by a strong functional connection between the green (plant–herbivore‐based) and brown (detritus–detritivore‐based) parts of the food web, which both develop over successional time. However, the interlinked changes in green and brown food web diversity patterns in relation to key ecosystem processes are rarely studied.
  2. Here, we demonstrate changes in species richness, diversity and evenness over a wide range of invertebrate green and brown trophic groups during 100 years of primary succession in a saltmarsh ecosystem, using a well‐calibrated chronosequence.
  3. We contrast two hypotheses on the relationship between green and brown food web diversity across succession: (i) ‘coupled diversity hypothesis’, which predicts that all trophic groups covary similarly with the main drivers of successional ecosystem assembly vs. (ii) the ‘decoupled diversity hypothesis’, where green and brown trophic groups diversity respond to different drivers during succession.
  4. We found that, while species richness for plants and invertebrate herbivores (green web groups) both peaked at intermediate productivity and successional age, the diversity of macrodetritivores, microarthropod microbivores and secondary consumers (brown web groups) continuously increased towards the latest successional stages. These results suggest that green web trophic groups are mainly driven by vegetation parameters, such as the amount of bare soil, vegetation biomass production and vegetation height, while brown web trophic groups are mostly driven by the production and standing stock of dead organic material and soil development.
  5. Our results show that plant diversity cannot simply be used as a proxy for the diversity of all other species groups that drive ecosystem functioning, as brown and green diversity components in our ecosystem responded differently to successional gradients.

Show less
Mammalian herbivores, grass height and rainfall drive termite activity at different spatial scales in an African savanna
Gosling, C.; Schrama, M.; Olff, H.; Cromsigt, J.P.; Erk, A. van 2016
Mammalian herbivores, grass height and rainfall drive termite activity at different spatial scales in an African savanna
Article / Letter to editor
closed access
Evaluatie van vegetatiegegevens in relatienotagebieden
Runhaar, J.; Linden, M. van der; Olff, H.; Zelfde, M. van 't 1993
Evaluatie van vegetatiegegevens in relatienotagebieden
Internal report
open access