Many types of vegetation have more or less ground cover and recruitment of new individuals often occurs only in temporarily empty patches or gaps. Ever since Watt’s (1947) Presidential address to the BES, the Journal of Ecology has been publishing the results of investigations into the importance of processes in such gaps in the determination of community structure. Three recent papers from Norway, the UK and the USA (Vandvik 2004, Turnbull et al. 2004 and Ewanchuk and Bertness, 2004, respectively - all in volume 92, issue 1), report different approaches to addressing this issue.
Working in salt marches in New England, USA, Ewanchuk and Bertness show that the recolonisation of gaps generated by ice scour is slow and driven by competitive processes. Parts of these marshes consist of patches of sparse, but species-rich, vegetation dominated by non-grassy herbaceous plants (forbs). These areas were found to be inhospitable to plants which grew well nearby, suggesting physical limitation at the local scale, while the forbs were restricted to these patches by interspecific competition.
Vandvik showed that revegetation of gaps in subalpine grassland in Norway depended upon gap size and grassland age along a gradient of secondary succession. The degree to which individual species depended on gaps for regeneration changed as the disturbance regime altered during succession, with such gap phase processes being important for a majority (74%) of species in the system. Taking a more mechanistic and small-scale approach, Turnbull et al. also found that most species of annuals in a limestone grassland showed a preference for colonizing unvegetated patches. Through a series of exacting and careful measurements of individual plants and neighbourhood modeling they derived individual-level competition coefficients for seven annuals. Seed size was found to be a key trait determining both competitive and colonizing ability.
Becky Allen | alfa
Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel
Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
In an article that appears in the journal “Review of Modern Physics”, researchers at the Laboratory for Attosecond Physics (LAP) assess the current state of the field of ultrafast physics and consider its implications for future technologies.
Physicists can now control light in both time and space with hitherto unimagined precision. This is particularly true for the ability to generate ultrashort...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
19.04.2018 | Materials Sciences
19.04.2018 | Physics and Astronomy
19.04.2018 | Physics and Astronomy