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Managing biological resources: Anthropogenic
pressure on plant community structure in Mt. Marsabit
forest, Kenya
* 1 Eunice W. Githae and 2 David W. Odee
1 School of Natural Resource Management, Narok
University College, P. O. Box 861-20500, Narok, Kenya
2 Drylands Research Programme, Kenya Forestry
Research Institute (KEFRI), P. O. Box 20412-00200,
Nairobi, Kenya
*E-mail for correspondence: egithaeh@gmail.com
Abstract
Mt. Marsabit forest is the main water catchment in
Marsabit district and the main source of foliage for
livestock to the surrounding communities. Currently, the
forest is under anthropogenic pressure leading to
continued habitat degradation and loss of biomass and
diversity on the mountain. This study was therefore
conducted to identify the impacts of human activities on
vegetation structure and composition in order to
develop strategies for its conservation and proper
management. Fifty two species of trees and shrubs,
twelve species of herbs and six species of climbers and
lianas were recorded belonging to 35 families and 64
genera. Rubiaceae was the richest family observed with
nine species. Rinorea convallaroides (Bak.f.)Eyles ssp.
Marsabitensis, Grey-Wilson (Violaceae), an endemic
species, and Drypetesgerrardii Hutch. (Euphorbiaceae)
had more than a third of the total importance value.
Eight vegetation associations were identified based on
the dominant species, namely; Croton dichogamous,
Strychnos henningsii, Rinorea convallaroides,
Erythroxylum emerginatum, Cassipourea malosana,
Teclea simplisifolia, Olea europaea and D. gerrardii.
Most of the vegetation types were highly disturbed by
grazing, honey harvesting and firewood collection.
There was a high proportion of open canopies
predominated by light-dependent species e.g. Ocimum,
Bauhinia and Asparagus species, indicating severity of
the disturbance. The density of tree communities with
30 cm diameter at breast height was very low, an
indication of climax vegetation elimination. Women and
children played a major role in vegetation changes
through collection of wood and non-wood forest
products as a source of income. The success and future
management and conservation strategy of the forest
will largely depend on how to reduce the human
pressure. This can be done by development of
community agroforestry projects in order to provide
both wood and non-wood forest products to the
communities as well as silvo-pastoralism for high quality
fodder for their livestock.
Diversity and pathogenicity of ophiostomatoid fungi
found on native trees in the Cape Floristic Region
Tendai Musvuugwa
Stellenbosch University, South Africa
Email for correspondence:tmusvuugwa@gmail.com
Abstract
Almost nothing is known about fungi associated with
native trees in South Africa, yet many plant species are
evidently threatened by native and exotic fungal
species. Ophiostomatoid group of fungi comprise
serious plant and human pathogens. It is therefore
important to investigate the ecology and diversity of
ophiostomatoid fungi associated with native trees in the
Cape Floristic Region (CFR) of South Africa. Bark and
wood samples were collected from diseased native
trees of the CFR. Ophiostomatoid fungi were isolated
from collected samples and sequenced for
identification. Some of the fungi were tested for their
pathogenicity on native trees. Potential vectors
(ambrosia and bark beetles and mites) of these fungi
were collected and identified. Feeding studies were
conducted for some of these mites on the fungi they
vector and fungi that they do not normally vector to
give an indication of the ease of host jumping. Eighteen
ophiostomatoid fungal species have been collected and
ten are new species. Some of them were pathogenic on
various native tree species such as
Rapaneamelanophloeos, Oleacapensis and
Curtisiadentata. Numerous beetles and mites were
identified as vectors of ophiostomatoid fungi. Some of
these mite species feed on ophiostomatoid fungi and
showed a high level of specificity towards the fungi they
normally vector.
Keywords: Ophiostomatoid, pathogenic, vectors
Keywords: Biodiversity, Conservation, Community
structure, Disturbance, Mt. Marsabit forest,
TAAG First African Student’s Conference, Nairobi. 2-4 July, 2013 39