Premium
Population ecology of Acacia tortilis in the semi‐arid region of the Sudan
Author(s) -
Kennenni Legesse,
Maarel Eddy
Publication year - 1990
Publication title -
journal of vegetation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 115
eISSN - 1654-1103
pISSN - 1100-9233
DOI - 10.2307/3235719
Subject(s) - acacia , arid , biology , population , ecology , basal area , woody plant , population density , crown (dentistry) , population ecology , botany , demography , medicine , dentistry , sociology
. The population ecology of Acacia tortilis , one of the important woody species in the arid and semi‐arid regions of northern Africa, was studied in the Sudan: Ten sample plots were established and all individuals in the plots were mapped and their basal diameter, stem height, crown height and cover measured annually for three years. Individuals were grouped into different height‐classes, ‘life‐forms’: trees >1.65 m, shrubs > 0.65 m and < 1.65 m, saplings < 0.65 m and seedlings (saplings less than one year old). The population density was 510 ind./ ha in 1985, 432 ind. / ha in 1986 and 218 ind. / ha in 1987. The life‐form distribution of the population showed clear differences between plots and years. Mortality in Acacia tortilis , expressed as loss in individuals per year, amounted to 167 ind. / ha / yr. Drought and lethal cutting were found to be the main mortality factors. The population declined by 15.3 % from 1985 to 1986 and by 49.5 % from 1986 to 1987. Natality (recruitment), expressed as number of newly established saplings, was 13 ind. / ha / yr. Recruitment is apparently discontinuous and bound to years with a relatively high precipitation.