Woodland dynamics under the influence of elephants and fire in Northern Botswana

被引:52
作者
BenShahar, R
机构
[1] Department of Zoology, Oxford OX1 3PS, South Parks Road
来源
VEGETATIO | 1996年 / 123卷 / 02期
关键词
browsing; elephants; seedlings; semi-arid savanna; shrubs; tree mortality;
D O I
10.1007/BF00118268
中图分类号
Q94 [植物学];
学科分类号
071001 ;
摘要
Sustained elephant browsing and intense burning could result in the loss of woodlands under conditions where elephant densities are high, such as in northern Botswana. Three woodland types dominated by Acacia erioloba, Baikiaea plurijuga and Colophospermum mopane were monitored in plots and contemporary recruitment rates of woody plants were compared with the associated local elephant densities and fire occurrences. Woodland types differed with respect to structure, extent of elephant damage and the occurrence of fire. Canonical correlations indicated that high extent of fire damage and high elephant densities did not covary within the woodland types investigated. Low tree densities in some woodland types were associated with high elephant densities and new elephant damage to plants increased with high elephant densities during the dry season. Plots with an apparent high fire frequency had lower tree densities and higher cover abundance of shrubs and seedlings. The annual rates of tree recruitment/loss in each woodland type were estimated through a model based on observed seedling recruitment, mortality and reversal to lower height classes due to combinations of fire occurrence and elephant browsing. The model suggested that elephants induce tree loss in woodlands dominated by plant species which are principal food sources. Fire however, seems to have a widespread effect across woodlands which could result in extensive tree loss.
引用
收藏
页码:153 / 163
页数:11
相关论文
共 26 条
[1]  
ANDERSON E, 1974, INT REV CYTOL S, V4, P1
[2]  
[Anonymous], ELEPHANT HABITAT REL
[3]  
BARNES RW, 1983, J APPL ECOL, V20, P123
[4]   PATTERNS OF ELEPHANT DAMAGE TO VEGETATION IN NORTHERN BOTSWANA [J].
BENSHAHAR, R .
BIOLOGICAL CONSERVATION, 1993, 65 (03) :249-256
[5]  
BHALOTRA YPR, 1987, CLIMATE BOTSWANA
[6]   MAXIMUM RATE OF INCREASE IN THE AFRICAN ELEPHANT [J].
CALEF, GW .
AFRICAN JOURNAL OF ECOLOGY, 1988, 26 (04) :323-327
[7]  
CAUGHLEY G, 1976, E AFR WILDL J, V14, P265
[8]  
Child G., 1968, TA2563 FAO
[9]  
CRAIG CG, 1990, P KAL CONS SOC GAB B
[10]  
CROZE H, 1981, DYNAMICS LARGE MAMMA, P68