Flower and fruit production of Mesogyne insignis engler in the forests of Amani nature reserve and adjacent areas, east Usambara mountains,Tanzania

Flowering and fruiting phonological patterns of an endemic species Mesogyne insignis (Moraceae) was studied in both continuous and fragmented forests in and around Amani Nature Reserve between September and November 2008 with an objective to compare flower and fruit production. The specific objectives of the study were (i) to determine the flower growth and fruits development and (ii) to determine the ratio of male to female flowers in continuous and fragmented forests. A total of 90 M. insignis trees were examined for stem diameter size-class distribution in both forests. Flower growth in terms of width and length and fruit development was monitored in 112 flowers, while flower sex ratio was monitored in 1124 flowers. Stem diameter size-class distribution was significantly different between the two forest types (t-test: t=3.5, p=0.001). Fragmented forests had a wider range of stem diameter (7.5mm - 134.6mm) than continuous forests (10.3mm-65mm). More flowers (59) developed in fragmented forest than in continuous forests (53) but statistically the difference was insignificant (t-test: t=1.77, p=0.36). The number of fruits set was significantly higher in continuous forests (26) than in fragmented forests (12) (t-test: t=4.21, p=0.001). Growth rate in length of male flowers was higher in continuous forests 0.42±0.22mm/day than in fragmented forests 0.36mm/day, statistically this difference was insignificant (t-test: t=0.37, p=0.72). Female to male flowers ratio was higher in fragmented forests (0.11) than in continuous forests (0.08) but statistically the difference was insignificant (t=2.48, 0.2<p<0.5). Clusters of male to female flowers were significantly different between the two forest types (t-test: t=0.04, p=0.02). Based on these results it seems forest fragmentation affect fruit production but not flower growth. Further study on the effect of abiotic factors on flower and fruit production of this species is recommended. The study should also be extended to other mountain blocks of Eastern Arc Mountains where forests are less fragmented to see if flower growth and fruit development in M. insignis are the same or different from the present results.