| dc.description.abstract | Mt. Marsabit forest is isolated by semi desert and desert, with vegetation ranging from
scrubland at the base to tropical rain forest at the peak. The forest has abundant pendant
bryophyte cover at the peak. The mountain rises from 950 m. asl. lowland of to 1750 m.
asl., ruling out the possibility of the forest supported by underground water. The annual
rainfall of 1,000 mm received by the forest is not enough to support the tropical rain
forest at the peak. The forest experiences consistent mist throughout the year. The
development of a forest in a situation where water is a limiting factor to community
development inspired this study.
The forest is currently threatened by invasive species e.g. Caesalpinia decapetala,
Lantana camara, Eucalyptus spp., Senna spectabilis, Ocimum suave, in addition to other
anthropogenic activities.
The objectives of this study were to assess the diversity of bryophytes in Mt. Marsabit
forest, collect bryophyte specimens and assess the role of bryophytes in mist water
trapping for forest community development.
To achieve this, the forest was studied through 3 windows transects, and in quadrats 400
m. x 400 m., 26 quadrats were randomized for study. Within each quadrat, nine sample
stations were sited. The first sample point 'was located at the centre of the quadrat, while ,
two more sample points were located 50m and 100m away from centre point. This was
repeated in the four compass directions. Bryophyte cover assessment was done using
25cm x 25cm quadrat. Data collection involved bryophytes specimen collection for NAI
, ..•
herbarium. The mist traps of 5()cm x 50cm, sandwiched 300g of bryophytes between
wires, were set up at 1450 m. asl., on the windward side. On the same site, stem
simulates of circumference 20 em, 35 em, and 53cm, dre~sedall round with Meteoriaceae
moss, were also set. The ·water retention capacity of _bryophytes was assessed, by
spraying water on naturally occurring mats of Meteoriaceae and Frullania angulata, for
30 minutes, then placed on wires until dripping stopped then weighed. The hygroscopic
capacity was assessed by oven drying the moss at 80 .C for 4 days, and weighed hot. The
dried moss was kept in a room at 20 . C and 70 % relative humidity for 4 days and
weighed.
The species diversity is high on Mt. Marsabit forest, with high altitude quadrats recording
the highest diversity. This study found 93 species of bryophytes with 51 mosses species
in 30 moss families, 39 liverwort species in 13 liverwort families and 1 species of
Anthocerotae and 81 new entries for the northern semi arid region of Kenya (K1). The
mist water collected in trap reservoir was 1 - 2 liters of water per meter squared per mist
day, conformed to results in Atacama Desert. The bryophytes water (intercept) retention
capacity of 6.8 liters of water per meter squared per day, which is more than 600 times its
own dry weight.
The total amount of mist water trapped by a hectare of bryophytes is 70,000 liters each
mist day. Working with a conservative figure of one misty day a week, a hectare of
bryophytes trap more than 4.5 million liters annually. The small branches use less than
half of their surface area to trap more mist water than the large stems, with an average of
1000 ml of water per meter squared per mist day. Hygroscopic capacity assessment
showed a weight gain of 13 % of both Meteoriaceae and Frullania angulata dry weight.
The results give evidence that mist water is important compensation factor that have
supported development of Mt. Marsabit forest community. Considering mist water
trapped by bryophytes, epiphytes, tree stems, branches and leaves, more water resource is
availed to the forest community than is evident by conventional methods of measuring
physical climatic parameters. It is the,mist water trapped by bryophytes and vegetation
that is the compensation factor, which maintain Mt. Marsabit forest community. The mist
water can be trapped and availed to community outside the forest, as a way to conserve
Mt Marsabit forest. The phenomena apply to many high ,altitude forests, particularly mist
forests. | en |
