ISSN:
1573-5052
Keywords:
Dynamics
;
Models
;
Succession
;
Vegetation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Successional change is thought to be at least partially driven by forees originating from within the community, namely by ‘reaction’ and competition. Both processes operate through changes in the environment, but from the literature on the subject it is not clear how they differ. To clarify these issues successiens of model communities are studied. This leads us to conclude that competition represent an instantaneous interaction, whereas reaction has historical aspects since it relies on cumulative changes in the environment. The three models considered-one relying on reaction to cause vegetational change, one relying on competition and differential growth rates, and a hybrid third one-yield very similar predictions: roughly bell-shaped curves displaced along the time axis. This shows that the mere fit of a certain model to successional data may easily be spurious (recently some workers have empirically fitted models identical to one derived here from first principles). The three models do behave radically different under perturbation, however: any model relying completely or partially on historical interactions cannot account for the well known possibility of artificially arresting succession. Even if the importance of historical interactions in succession (i.e. the Markovian character of succession) cannot easily be ascertained, one can nevertheless ask whether historical interactions are at all necessary for the explanation of successional change. It is argued here that succession can be entirely understood in terms of instantaneous interactions, notably competition. The argument rests upon the well known relationship between colonizing and competitive ability, and on the fact, proven here, that stress, defined as expressing itself in severe random fluctuations in the growth parameters, is negatively correlated with competition intensity.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00052020
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