Jose Hierro
 
 

Fire-Vizcacha interaction as a self-organizing process.

    Both fire and vizcacha herbivory are self-organizing processes in the semi-arid shrubland of La Pampa province in Argentina; that is, they produce patterns in the ecosystem which persist in time and, in turn, influence the behavior of future occurrence of these processes (Holling et al. 1996). Fire and vizachas interact and this interaction can be described as a synergistic phenomenon that produces a self-organizing process. Vizcachas' herbivory influences fire spread by creating natural"firebreaks" around their communal burrow systems, the presence of these natural firebreaks produces a mosaic of shrub patches in the landscape that differ in height and biomass, with taller shrubs and greater biomass on the top of the borrow systems. Future occurrence of the interaction will tend to reinforce this pattern, maintaining these shrub patches through time.

Dorota Porozinski

SELF-ORGANIZATION
Dorota L. Porazinska
Entomology and Nematology Department
 

    Self-organization in natural systems possibly relates to the formation of the most efficient structures of both biotic and abiotic ecosystem’s components.  This efficiency is manifested throughout all levels of ecosystem’s organization.  The outcomes of self-organization result from the most basic biological and ecological functions of the keystone species (or group species) and keystone abiotic factors (e.g. fire).  Social and political forces play secondary roles in self-structuring of those systems.  They relate more to security of perpetuation of the self-organizing phenomenon.
 
    In contrast, agroecosystems have a very narrow spectrum of self-organization at the biological and ecological levels.  Self-organization here is limited to growing time (from few months to few years), and is dictated by the crop type.  Social aspects override the biological and ecological functions.  Whether a particular system will organize itself at the biological or ecological level around this or other crop, is determined predominantly by the economic value of the particular crop (social factors).  Types of agricultural management practices (monoculture vs. cropping systems, organic vs. synthetic fertilizers, pest occurrence and pest control, etc.) will additionally affect the paths of biological and ecological self-organization of an agroecosystem.

    Sugarcane production in the Everglades Agricultural Area in Florida perfectly illustrates an agricultural ecosystem organizing itself very strongly around social and political issues.  For instance, progressing subsidence of the soil thickness can indicate very minimal self-organization at biological or ecological level (or the system is self-destructing since soil oxidation is caused by aerobic bacteria).  However, understanding the consequences of loosing fertile agricultural soils brings social self-organization.  As a result, alternative management tactics which attempt to increase the spectrum of biological and ecological organization are proposed.