Diversity and distribution of vascular plant species along an altitudinal gradient in Kindoroko forest reserve, Tanzania

This study was conducted at Kindoroko Forest Reserve (KFR), which is part of the Eastern Afromontane biodiversity hotspot. The objective of the study was to assess vascular plant species diversity and distribution along an altitudinal gradient. Sampling for vegetation was done depending on the habit type to be sampled i.e. herbs, shrubs and trees. Locations of sample plots were guided by changes in altitude which were placed after every 50 m increase. Species diversity, richness and evenness were all calculated using Species Diversity and Richness software. Plant community structure were assessed using both ordination and classification methods using Community Analysis Package Software. The population structure was expressed in graphic form as histogram. A total of 83 vascular plants belonging to 47 families were identified. The overall results from the study indicated higher species diversity for herbs as 1.51 in the mid altitude as opposed to lower and upper altitude. Shrub species diversity 1.52 was higher in low altitude than mid and upper altitude and tree species had higher diversity in low altitude 1.77 against the mid and high altitude. Based on TWINSPAN a total of five plant communities in KFR were recognized. However when herb and shrub species were treated separately they resulted into four plant community types. The ordination diagrams showed a clear separation of low altitude plots, but not for mid and high altitude plots. Results for population structure when all trees were pooled together showed Reverse J-shape structure, an indication that it is a health population. However individual tree species with a deviation from the expected reversed J-shape are presented and discussed. More studies on environmental variables should be conducted to better understand factors influencing species distribution in KFR