the Mpingo Conservation Project - Coastal Forests of Kenya and ...

The Mpingo Conservation Project
Final Draft
Mpingo Survey 2000 Full Report
Results
Study Site Unburned Burnt Riverine Overall Mean
2 : Kimambi 0% 0% 15% 6%
2 : Mkoka 42% 0% – 33%
Strata 2 Overall 31% 0% 15% 22%
3 : Barikiwa 20% 14% 60% 33%
3 : Kilimarondo 24% 57% 25% 36%
Strata 3 Overall 22% 43% 44% 35%
All study sites 19% 16% 22% 19%
Any spp. juvenile 92% 75% 83% 85%
Mpingo at Migeregere 21% 33% 37% 30%
Table 9. Frequency (%) of encountering juvenile mpingo in survey plots by plot type and study site, with totals for
strata and for all sites, and the totals for all juveniles of all species and Tanzanian Mpingo 98 data from Migeregere for
comparison.
Mpingo juveniles accounted for only 4.6% of woody juveniles counted in the 2m radius sub-plots.
Where mpingo juveniles were found, saplings accounted for 73% of juveniles as against 48% for all
other species and a roughly even split at Migeregere. This is reflected in the increase in mean height for
the centre juvenile which is 1.81m for mpingo, but 1.53m on average for all species. 21
Ball (2004) found the likelihood of mpingo juveniles being present at Migeregere doubled where the
total tree canopy cover in the surrounding 5m radius sub-plot was 40% or less, but the likelihood
remains almost constant for sub-plots thus surveyed by this expedition. 22 In fact this result is reversed
when canopy cover over the entire 20m radius plot (not available for the Migeregere data) is
considered; now the likelihood of mpingo juveniles being present rises from 17% in plots where
canopy cover over the whole plot is equal to or less than 40%, to 24% mpingo juvenile presence where
canopy cover over the entire is plot exceeds 40%, although this result is not significant (Binomial test,
n = 90, p > 10%). Juveniles of other species appear to follow a similar pattern but gaps in the data
prohibit statistical analysis.
Figure 11 shows in more detail the variation between categories of canopy cover of the presence of
mpingo juveniles for study sites in strata 2 and 3. Riverine plots which do not have total (76-100%)
canopy cover are generally on smaller ephemeral water courses which do not harbour the distinctive
thicker ground-water forest. Mpingo juvenile were found there with a significantly greater frequency of
50% as against the average encounter rate of 30% in site strata 2 & 3 (Binomial test, n = 25, p < 5%),
but the associated test for riverine courses with total canopy cover is not significant due to a low
sample size (n = 5, p > 10%). Burnt plots with a low canopy cover also appear to exhibit an extremely
low frequency of mpingo juvenile presence, and this is significant (n = 10, p < 5%).
21 Owing to the deliberate location of sub-plots around mpingo juveniles where present, the presence or height of other
species cannot be said to be independent of the presence or height of mpingo, and so these differences in the data do not
readily present themselves to statistical analysis.
22 Mpingo juvenile presence varies slightly from 34% where the canopy cover is less than or equal to 40%, to 36% where
canopy cover is over 40%. The inconsistency with Table 9 is a result of a much reduced data set (n = 91 compared to 240) for
canopy cover within the 5m radius sub-plot. This inconsistency is statistically significant (p < 0.1%), though there is no
obvious explanation and illustrates the hazards of working with partial data sets.
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