1. A new method to evaluate the interaction between individuals competing for light in a monospecific stand is presented. 2. Light intercepted by a leaf of a target individual is influenced by its own leaves and those of neighbours higher in the canopy. We assume that light intercepted by the leaf is the sum of the light that penetrates the foliage of the target and the foliage of neighbours. We define the degree of the interaction as the fraction of the intercepted light that penetrated the foliage of neighbours. 3. To determine the degree of interaction, we established experimental stands of an annual, Xanthium canadense Mill., and measured light interception directly with light-sensitive films attached to leaves. We calculated the interaction using light absorption of individuals within the stand and of those isolated from the stand. Light interception of an individual was influenced more by its neighbours' leaves than by its own. The degree of interaction was greater in the stand of higher density. 4. The method presented here may be useful in studying the role of architectural characteristics in light competition in relation to evolutionarily stable strategies of individuals in monospecific stands.
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics