The origin of Dahomey Gap (DG) flora is one of the central biogeographical questions in sub‐Saharan, which has been addressed in several studies. However, floristic evidence based on representative samples from the DG seems to be lacking in the scientific debate. The present study was conducted to fill this gap. Specifically, we assessed Togolese mountain riparian forests as minor forest refugia, examined their contribution to larger sub‐Saharan forest refugia, and discussed the significance of these findings for biogeography and biodiversity conservation. Southwest Togo, West Africa, and sub‐Saharan Upper Guinea Region Floristic data were collected in riparian forests through an intensive botanical inventory (
n
= 198; 50 × 10 m
2
). A comparative analysis was performed based on the floristic evidence related to forest refuges. The results showed significantly high species richness (868 species) and a high gamma and beta diversity associated with spatial turnover patterns. They also showed a high affinity between the study forests and large sub‐Saharan forest refugia. Riparian forests share about 60% of their current species richness with large sub‐Saharan forest refugia and contained refuge bio‐indicator species. The floristic evidence, consistent with those of other studies, suggests that Togolese mountains would have very ancient origins and have experienced paleoclimatic events. The studied riparian would have served as refuges during recurrent climatic episodes. Our results support the minimal forest fragmentation hypothesis (network of refugia along rivers). However, they seem to be incompatible with the idea that the DG flora may be essentially a relic of the early Holocene. In sub‐Saharan Africa, where maintaining a vast area of natural forest is difficult due to human pressure, efforts to preserve maximum species diversity should include a focus on the conservation of minor forest refuges, particularly in sub‐humid mountain riparian zone.
Aims Although minor climatic forest refuges were important as key areas
for the long-term persistence of species and genetic diversity, and can
again function as refuges during present and future climatic changes,
they have received little attention in sub-Saharan Africa. The
objectives in this paper were to assess the Togolese montane riparian
forests as minor sub-Saharan forest refugia, examine the contribution of
minor sub-Saharan forest refugia to the larger forest refugia using the
Togolese montane riparian forests as a model, and discuss the
implication of these results for biogeography and forest biodiversity
conservation in sub-Saharan tropical Africa based on the floristic
approach. Location Southwest Togo, West Africa, sub-Saharan Upper Guinea
Region Methods Floristic data were collected across Togolese mountain
riparian forests through an intensive botanical inventory using the
survey approach (n=198; 50×10 m2). A comparative analysis was performed
on the basis of floristic criteria and attributes related to climatic
forest refuges. Results According to floristic attributes, the riparian
forests of the subhumid Togolese mountains were important minor refuges
for rainforests during Pleistocene warming. They share about 60% of
their current species richness (868 species) with the large sub-Saharan
forest refuges. Main conclusions The floristic data were similar to that
of previous studies focusing on the forest refugia around the DG and
elsewhere worldwide. However, they seem to be incompatible with the
ideas that the DG forest flora may be essentially a relic of the early
Holocene, when the geographical distribution of the Guinean-Congolian
forest was maximum. Efforts to maintain maximum species diversity in
sub-Saharan Africa should therefore pay particular attention to the
conservation of minor forest refugia. This study asks important
questions about the patterns of disjunction, which should be focused on
in further studies. Keywords Tropical biodiversity, Forest refuges,
Floristic approach, Dahomey Gap (DG), Togolese Mountain, Vegetation
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