A preliminary assessment of the extent and potential impacts of alien plant invasions in the Serengeti-Mara ecosystem, East Africa
Date
2017
Journal Title
Journal ISSN
Volume Title
Publisher
AOSIS Publishing
Abstract
This article provides a preliminary list of alien plant species in the Serengeti-Mara ecosystem
in East Africa. The list is based on broad-scale roadside surveys in the area and is supplemented
by more detailed surveys of tourist facilities in the Masai-Mara National Reserve and adjoining
conservancies. We encountered 245 alien plant species; significantly more than previous
studies, of which 62 (25%) were considered to have established self-perpetuating populations
in areas away from human habitation. These included species which had either been
intentionally or accidentally introduced. Of the 245 alien plants, 212 (including four species
considered to be native to the region) were intentionally introduced into gardens in the
National Reserve and 51 (24%) had established naturalised populations within the boundaries
of these tourism facilities. Of the 51 naturalised species, 23 (11% of the 212 alien species) were
recorded as being invasive within the ecosystem, outside of lodges and away from other
human habitation. Currently, the Serengeti-Mara ecosystem is relatively free of widespread
and abundant invasive alien plants, with a few exceptions, but there are extensive populations
outside of the ecosystem, particularly to the west, from where they could spread. We address
the potential impacts of six species that we consider to pose the highest risks (Parthenium
hysterophorus, Opuntia stricta, Tithonia diversifolia, Lantana camara, Chromolaena odorata and
Prosopis juliflora). Although invasive alien plants pose substantial threats to the integrity of the
ecosystem, this has not yet been widely recognised. We predict that in the absence of efforts to
contain, or reverse the spread of invasive alien plants, the condition of rangelands will
deteriorate, with severe negative impacts on migrating large mammals, especially wildebeest,
zebra and gazelles. This will, in turn, have a substantial negative impact on tourism, which is
a major economic activity in the area.
Conservation implications: Invasive alien plants pose significant threats to the integrity of the
Serengeti-Mara ecosystem and steps will need to be taken to prevent these impacts. The most
important of these would be the removal of alien species from tourist facilities, especially those
which are known to be naturalised or invasive, the introduction of control programmes aimed
at eliminating outlier invasive plant populations to slow down the spread, and the widespread
use of biological control wherever possible.
Description
CITATION: Witt, A. B. R., et al. 2017. A preliminary assessment of the extent and potential impacts of alien plant invasions in the Serengeti-Mara ecosystem, East Africa. Koedoe, 59(1), a1426, doi:10.4102/koedoe.v59i1.1426.
The original publication is available at https://koedoe.co.za
The original publication is available at https://koedoe.co.za
Keywords
Invasive plants, Alien plants
Citation
Witt, A. B. R., et al. 2017. A preliminary assessment of the extent and potential impacts of alien plant invasions in the Serengeti-Mara ecosystem, East Africa. Koedoe, 59(1), a1426, doi:10.4102/koedoe.v59i1.1426