Aspectos de la biología de poblaciones de Inula viscosa en un campo abandonado

Abstract

1. Inula viscosa (L.)Aiton is a shrub that have reached a great dominance on extensive areas of abandoned arable land in many parts of Catalunya and others Mediterranean regions of Spain. 2. The structure and development of a population of this species on a field abandoned in 1970 were studied over a 3-year period. 3. The age structure of individuals can be used to derive an approximation of the population growth in time and suggest: a. The population increased in density during the first 3-4 years of colonization and since the fourth year showed a trend to stabilization. b. After 9 years of colonization the population attained a senile state. 4. The survivorship curves of stems cohorts born in 1976, 1977 and 1978 and the depletion curves of others cohorts born in previous years, showed that the mortality rate of each cohort increased from the older to the younger cohorts, so the life span of cohorts were shorter every year (1 year for the cohort born in 1978). The corollary of this point is that the individuals of inula will change its life form from chamaephyte (or nanophanaerophyte) to hemicryptophyte in an inminent future.