Population Demography and Dynamics of Acacia tortilis in South Sinai

Abstract

Demography of Acacia tortilis (Forssk.) Hayne subspecies raddiana demonstrated that the estimated average age of the oldest individuals in the population reached 614 ± 91.7 years old. About 50 % of the trees have an age range from 5 to 50 years, while only 12.5% of the trees are of age less than 5 years. During January the leaves cover about 44 % of the tree branches while the rest of the branches were naked. The maximum leaf cover occurred in February (56 %). The leaf senescence on the main branch increased till June reaching 64 %. The minimum leaf cover takes place in November (8 %) where the branches seem to be naked due to leaf senescence and shedding. During December, the leaf cover reached about 38 %. A. tortilis flowered twice in the year; the first flowering event begins on old branches in late

February and early March, while the second flowering event begins on the new branches in July.

Life table analysis and fecundity schedules showed that the flowers, seeds and seedlings are the shortest stages in the life span. The net reproductive rate was 0.281, the estimated intrinsic rate of increase reached -0.00337 per capita per year and the average generation time of the species attained about 380 years. Population demography, phenology and life table analyses draw the attention towards specific conservation considerations to manage the species populations in the protected and non-protected sites.