Intl. J. of Mol. Evol. and Biodivers. 2013, Vol. 3, No.2, 5-10
http://ijmeb.sophiapublisher.com
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done to provide early bush of palpable tender grass for
livestock needing in areas of wildlife conservation.
Despite the value of early burning, such fires are
uncontrolled and therefore penetrate ecosystems
leading to loss of biodiversity. Late burning is done to
hunt for game animals by hunters and farmers and are
set indiscriminately, burning all fuels along its course
and coming to rest after much destruction when there
is no more fuel within an ecosystem.
Plate 1 Fire burning in ecosystem in Abeokuta, Ogun state,
Nigeria
3
Observed effects of fire on plants and
animals
The ability of a tree cambium to withstand fire
intensities of different durations is dependent on bark
thickness and bark thermal properties (Adegbola,
1985;
Coppedge et al., 1998). This is due to the fact
that fire decreases the density of woody stems and that
late burning has a marked effect than early burning.
Experiments have been carried out by Forestry
Institute of Nigeria on the effect of burning on trees
since 1929. The experiments were carried out on 0.17
hectare each for each treatment. The plots were
separated by fire traces of 3.3 m wide (Plate 2).
The treatments given to the plots are stated below:
Plot A: annual burning late in the dry season
(
mid-march)
Plot B: annual burning early in the dry season
(
December)
Plot C: no treatment (protected from fire).
The summary of the fire effects is presented in tabular
form below.
Table 1 data showed that there was general decrease in
number of trees in all the three plots. Late burnt plot
had the highest mortality while protected plot
recorded the least mortality rate between 1991 and
1995.
Decrease in trees in plots A and B is attributed
to the effect of fire while in plot C decrease is
attributed to natural mortality as dictated by prevailing
climatic factors.
Plate 2 A newly burnt piece of land for agriculture in Abeokuta,
Ogun state, Nigeria
Equally, the effects of fire on wildlife resources was
observed through farming activities which encouraged
the destruction of ecosystem or the emergence of
modified ecosystem to boast food production. In
farming, forest is cut down and fire is employed as a
tool for clearing. Accordingly, Adewale (1997,
unpublished data) reported the effect of wildfire on
wildlife biodiversity in a study carried out in
Abeokuta game animal populations in farmlands with
secondary forest regrowth. The method used was mark
and recapture method to prevent over-estimation of
species and population. The treatment used on the
farm is stated below:
All sample plots: traps set in evening and inspected
every morning. The traps were baited with cassava,
maize and oil palm fruits. Every morning, captured
rodents were marked; number captured recorded and
released back into the surrounding. Rodents were
marked by clipping their ears, toes or tails. The
observation lasted for two months.
Table 2 data showed that large wild animals have
migrated out of the modified ecosystem or trapped and
killed by fire during land preparation. However, days
without data had no animal information for the days.
Wildfire runs through ecosystem destroying habitat,
trapping and killing animals, increasing animal
susceptibility to diseases and encouraging new pathogens