International Journal of Molecular Evolution and Biodiversity 2016, Vol. 6, No. 2, 1-6
1
Research Report Open Access
Estimating Vegetation Change in Saadani National Park
Henry K. Njovu, Ladislaus. W. Kahana , Elizabeth Kamili, Gideon Alfred, Rudolf Mremi
College of African Wildlife Management, Mweka, P.O Box 3031, Moshi, Tanzania
Corresponding author email
International Journal of Molecular Evolution and Biodiversity, 2016, Vol.6, No.2 doi:
10.5376/ijmeb.2016.06.0002
Received: 28 Dec., 2015
Accepted: 08 Feb., 2016
Published: 28 Mar., 2016
Copyright © 2016
This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use,
distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article
:
Njovu H.K., Kahana L.W., Kamili E., Alfred G. and Mremi R., 2016, Estimating Vegetation Change in Saadani National Park, International Journal of Molecular
Evolution and Biodiversity, 2016, 6(2), 1-6(doi:
10.5376/ijmeb.2016.06.0002
)
Abstract
Maintenance of species diversity is one of the prime objectives of establishing protected areas network and the main
responsibility of wildlife managers. We report results of the study which aimed at estimating vegetation change in Saadani National
Park. Specifically, we determined abundance in terms of relative density and variation in diversity between old and regenerating tree
populations. Data were collected using a Point Centered Quarter method. A total of 800 trees were measured. Results revealed
significant variation in species diversity between regenerating and the old tree populations (F
1,18
8.146, P < 0.01). The relative density
of regenerating
Acacia zanzibarica
was (77%) and
Terminalia spinosa
(12%) respectively and higher than the corresponding old
population with (65.5% and 7.75% respectively). We recommend mechanical removal and efficient use of fire to prevent establishment
of
A. zanzibarica
seedlings and saplings in order to decrease its competitive dominance while promote the establishment of new tree
species. Conversely, management should look into the possibility of introducing medium sized browsers like impala in order to reduce
recruitment rate of
A zanzibarica.
Further to that, we recommend establishment of a long term vegetation monitoring study which will
detect spacio-temporal patterns of vegetation changes and the possible drivers.
Keywords
Abundance; Dominance; Regenerating trees; Relative density; Species diversity; Saadani National Park
1 Introduction
Tropical savannas are dynamic ecosystems alternating between woodland and grassland communities (Sinclair and
Arcese, 1995). The balance between grassland and woodland is controlled by complex interactions between edaphic
and climate factors (Higgins et al., 2000; Fuhlendorf et al. 2008), elephant (Laws, 1970; Myers, 1973; Caughley,
1976; Pellew, 1983), fire (Dublin et al., 1990), grazing (Riginos and Young, 2007) and browsing pressure (Prins and
Van der Jeugd, 1993). Variations in any of these factors can induce change in proportion of woody and herbaceous
which in turn affect vegetation structure, ecosystem function, primary productivity, plant diversity and abundance
as well as associated animal communities.
Plant abundance and diversity are among important attributes of community organization (Shaukat et al, 1978).
Plant abundance is a measure of plant numbers in a site (Hanski, 1982), whereas species diversity is an index of
diversity within an ecological community that incorporates both species richness which is the number of species in
a given area or a given sample and the evenness of species' abundances (Spellerberg and Fedor, 2003). For many
years ecologists have been using plant abundance (cover, frequency, density and biomas) and plant diversity (species
richness and species evenness) to quantify amount of vegetation changes. In Saadani National Park,
Acacia.
zanzibarica
is an indigenous tree species that seems to be the most competitive dominant species in the park. The
species has extended to areas that were historically grasslands. This has reduced the area available for grazing animal
and restricting smooth movement of animals in the park. The risk of vegetation changes in Saadani National Park
has been reported for more than a decade now (Bloesch and Klötzli, 2002; Augustine, 2003; Tobler et al., 2003;
Treydte, 2004), to date no study has been conducted to quantify amount of vegetation change in the area.
The study aimed at estimating vegetation change in Saadani National Park. Specifically, we determined abundance
in terms of relative density and variation in species diversity between the old and regenerating tree populations. We
hypothesize that regenerating tree population have lower species diversity than the old tree population. Findings
from this study will inform managers on the current vegetation status and suggest appropriate measures which can
