Plant Species Characteristics and Woody Plant Community Types within the Historical Range of Savannah Elephant, Loxodonta africana Blumenbach 1797 in Northern Togo (West Africa)

摘要

Aims: Assessment of plant species diversity and habitat typology. Study Design: Stratified random sampling design according to defined land categories of a land cover map. Place and Duration of Study: Complex of protected areas Oti-Keran-Mandouri (Northern Togo) from March to December 2014. Methodology: Floristic data, forest measurements (total height and diameter of woody species with diameter at breast height (DBH) greater than 10 cm) and 17 environmental variables were collected in plots of 50 m X 20 m; herbaceous species were recorded in subplot of 10 m X 10 m at the center of the big plot and juveniles (woody species with DBH<10 cm) were counted in three subplots of 5 m X 5 m installed diagonally. Floristic data were collected according to the phytosociological scale of Braun-Blanquet. After deletion of outliers, two different matrices were considered for canonical correspondence analysis (CCA) and .for hierarchical cluster analysis. Results: A total of 320 plant species were recorded in 182 plots and grouped in 209 genera and 66 families. The most frequent species were Piliostigma thonningii (2.90%), Pterocarpus erinaceus (2.90%), Combretum glutinosum (2.34%), Anogeissus leiocarpus (2.09%), and Terminalia laxiflora (2.09%). The species’ distribution was influenced by two major ecological gradients: habitat degradation and soil. The first four canonical axes of the CCA express 9.4% of the variance in species distribution and 50.4% of the variance in species-environment relation with a total inertia of 19.66%. Seven groups of woody plant communities were distinguished according to their species composition (0.35 ≤H≤1.43 and 0.37≤E≤0.83). Conclusion: Species composition and distribution are influenced by environmental variables especially anthropogenic activities. However, dominant species are relevant to large herbivores such as the African savannah elephant. Management system should be improved to maintain this important corridor.