Aboveground and below-ground community ecology

• Richard Bardgett

  Personal web site.

  Plant, soil, microbial interactions and ecosystem carbon cycling

  The last decade has witnessed an explosion of interest in the topic of soil carbon cycling, and especially the role that soils play in the global carbon cycle and climate change. This interest has come about largely because soils absorb and release greenhouse gases, including carbon dioxide and methane, and act as a major carbon reservoir, storing some 80% of the Earth’s terrestrial carbon stock. Despite the importance of soils for carbon storage, remarkably little is known about the factors that regulate the fluxes of C to and from soil, or about the role that interactions between plants and soil microbes play in regulating soil carbon sequestration. In this talk, I use selected examples from recent research to illustrate some of the mechanism by which plants and their interactions with soil microbes can influence soil carbon dynamics at different spatial and temporal scales, and demonstrate how such understanding might be harnessed to enhance soil carbon sequestration in grassland systems. Future challenges in this area of research will be identified.
  

• Michal Hájek

  Personal web site.

  Community composition of different groups of organisms in island-like fens and bogs
  
  During the last years a detailed investigation of species composition of vascular plants, bryophytes, molluscs, diatoms and testate amoebae have been carried out in the Western Carpathian and Suddeten mountains in Central Europe. This research found that pH/calcium gradient is a major driver of a compositional change in all investigated assemblages (although the underlying mechanisms differ by particular groups of organisms) and leads to apparent coincidences between community compositions of different organism´s groups. When working on a larger spatial scale, the biogeographical factors starts to play a bigger role. Species composition of the vascular plants and molluscs, both rather bad dispersers, is from a great part determined by spatial effects, which are largely connected to relictualism. We brought an evidence that particular vascular plants and mollusc species are significantly linked to old fens even at the millennial scale, and that age of a fen correlates significnatly with the density of fen specialists. For better dispersers (molluscs, diatoms and testate amoebae) these effects were not statistically significant. Both dispersal ability and life span matter also for bioindication. When we analysed relationships between species compositions and water chemistry in bogs scattered in recently limed forests, calcium concentration determined species composition of diatom and testate amoebae assemblages, but not species composition of vascular plant and bryophyte assemblages.
   

• Enrique Lara

  Personal web site

  Towards an integrative study of soil food webs

  Enrique Lara, Edward A. D. Mitchell, Laboratory of Soil Biology, University of Neuchâtel

  The soil microbial loop concept is 30 years old. Yet our understanding of soil microbial food webs is still fragmentary. Four key research areas directly relevant to soil food webs are insufficiently taken into account :
  1) Biodiversity: studies combining classical and molecular methods are revealing huge diversity both within known groups and novel unsuspected clades.
  2) Biogeography: Not all free-living protists are cosmopolitan ; what about functions ?
  3) Feeding habits and trophic position: What do all these species do for a living ? How common are food-specialists? Can this information be integrated into models?
  4) Spatial and temporal patterns: How can we account for complex spatial and temporal patterns when discussing soil microbial food web functioning?
  These important topics are typically studied by independent teams, which have different research backgrounds and scopes. New technological developments now allow assessing the full diversity of soil organisms and hopefully soon the position of each one in the food web. We now need to bring concepts and methods together to improve both theory and to design more ecologically realistic experiments.

• Edward Mitchell

  Personal web site.

  Above-ground vs below-ground pa tterns of communities: lessons from primary succession and disturbance gradients

• Frederick W. Spiegel

  Personal web site

  Sporocarpic and sorocarpic amoebae as tools for studying the amoeboid predators of decomposers.

  Sporocarpic and sorocarpic amoebae, the organisms colloquially called slime molds, produce sporulating structures on various types of decaying plant substrates. Their sporulating structures, termed fruiting bodies, allow them to be identified to species or species complex. Because of this, they can be collected and cataloged very easily. Culturing is not necessary as it is for most protist. This facilitates their use as indicators for the communities of eukaryotic microorganisms that act as predators of decomposers. Techniques for collecting and identifying slime molds from the various microhabitats (standing dead plants, tree bark, ground litter, humus, coarse woody debris, herbivore dung, and submerged dead vegetation) will be described and examples of community level studies of slime molds will be presented.