TITLE:
Structural Diversity of Woody Species in the Senegalese Semi-Arid Zone—Ferlo
AUTHORS:
Ousmane Ndiaye, Aly Diallo, Stephen A. Wood, Aliou Guisse
KEYWORDS:
Woody Taxa; Senegal; Ferlo; Drylands; Community Structure
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.5 No.3,
February
24,
2014
ABSTRACT: The combined effects of climate change and human pressure have led to the progressive degradation of natural resources in semi-arid
regions. Woody taxa in these regions play an important role in the functioning
and services provided by semi-arid savannah
by serving as forage for both domestic and non-domestic grazers. Maintaining
the functioning of semi-arid savannas thus requires understanding the dynamics
of these communities of woody taxa and their responses to exogenous forces,
such as climate. To better understand the dynamics of woody taxa in semi-arid
environments we collected dendrometric characteristics from five field sites
along an environmental gradient in the Ferlo region of central Senegal. Density
and basal area were found to be greater in the northern part of the zone,
contrasted with the distance between individuals and crown cover, which is
greater in the southern part of the zone. Stand structure estimated from the
distribution according to height and diameter at breast height shows a
preponderance of individuals in the shrub layer, although with a significant
representation of the tree layer in southern Ferlo. Stand regeneration was
better in the south and less effective in the north. There was a trend towards
the rejuvenation of populations belonging to the dominant species. There were
only three species for which degradation was not apparent (Balanites aegyptiaca, Acacia
raddiana and Dalbergia melanoxylon), all of which have important ethnobotanical
uses, suggesting that human use of taxa can play an important role in
preventing degradation. Three distinct groups of woody taxa were found to
correspond to gradients of precipitation, topography, and human land use
pressure. Our results suggest an important role in the management and
reintroduction of woody species in the Sahel and the regulation of pastoral
techniques necessary for the rehabilitation of the agro-pastoral zone of
Senegal.