Vegetation Dynamics
 
 
 
  This topic is presently at the frontiers of science in several ways. It touches also several disciplines (Biology, Chemistry, Physics, Geoscience, etc.). I came to three talks:
 
  1. Towards modeling of vegetation dynamics
  Role of vegetation dynamics in climate change
 
  2. Investigation of forest standings
  Field work, physiology
 
  3. Theoretical ecology
  population ecology, modeling of fire, stability of semi-aride zones
 
 
 
  Recent research initiatives aim at analyzing the mechanisms which control the growth dynamics and stability of ecosystems, at modelling and predicting how the ecosystem is disturbed by human activity and climate change, and at developing remedial management options. The changes have significant impacts on important wetland functions (biodiversity, stability of river and lake margins, water quality) and local economies. The scientific approach is multidisciplinary and comprises observational field studies, field experiments, controlled greenhouse and laboratory experiments, data collation and treatment, and mathematical modeling.
 
  Dynamic Vegetation Models are capable of simulating both ecosystem structure (vegetation distribution and phenology) and function (biogeochemistry). The new feature of this kind of model ansatz is that theses do not assume an equilibrium state between climate and vegetation. This is essential for the responses and impacts of the terrestrial biosphere under a rapidly changing climate. Short-term transient effects such as forest die-back in mid-latitudes, forest expansion in the boreal region or replacement of tropical forest can be captured by the models. They include the explicit representation of dynamic vegetation processes, e.g. resource competition and production, growth, mortality, establishment, soil and litter decomposition. This is based on a mechanistic description of photosynthesis, respiration, surface or canopy energy balance and allocation of carbon within the plant.
 
  References:
 
  Foley JA, Prentice IC, Ramankutty N, Lewis S, Pollard D, Sitch S, Haxeltine A, 1996, An integrated biosphere model of land surface processes, terrestrial carbon balance, and vegetation dynamics. Global Biogeochemical Cycles, 10, 603-628
 
  Friend AD, Stevens AK, Knox RG, Cannel MGR, 1997, A process-based, terrestrial model of ecosystem dynamics (Hybrid 3.0). Ecological Modelling, 95, 249-287
 
  Woodward FI, Lomas MR, Betts RA, 1998, Vegetation-climate feedbacks in a greenhouse world. Philosophical Transactions of the Royal Society of London Series B - Biological Sciences, 353, 29-38