PLANT PHENOLOGY IN RELATION TO WATER AVAILABILITY - HERBACEOUS AND WOODY SPECIES IN THE SAVANNAS OF NORTHERN CAMEROON

Phenological patterns of herbaceous and woody plants well represented in the Sudano-Sahelian savannas of northern Cameroon were studied in r elation to water availability in three contrasted soil types. Mean ann ual precipitation in this region is 800 mm, entirely restricted to the period May-June to September-October, but redistribution of rainwater by varying soil substrates leads to considerable heterogeneity in ava ilable water resources for plants. Results are discussed in terms of p robable competition for water resources among co-occurring plants and the adaptations shown by observed patterns to prevailing environmental conditions. Water stress is seen to be a limiting factor to plant gro wth but does not constitute the sole trigger for the phenological phas es observed, nor is it the principal factor responsible for the prepon derance of annual species in the herbaceous stratum.