Community structuration
The corresponding data (limited to the seven most captured small mammal
species) were subjected to cPCA at the scale of the 9 areas encompassing
the 49 localities, the first axis of which (Fig. S2) showed distinct
distribution trends for the exotic M. musculus and all other
small mammals. Mus musculus appears to be highly dominant overall
on the coastal area North of the Gambia as well as on the
Kaolack-Tambacounda axis, and present at high frequency in Tambacounda,
in localities around Kidira (at the Senegal – Mali border) and in
Haute-Casamance. Conversely, this species is absent from Basse-Casamance
and south-Eastern Senegal, where the exotic R. rattus or native
species mainly occur (Fig. 1). The second axis of the cPCA mostly showed
a contrasted distribution of both exotic species and C. olivierivs. the native M. natalensis which is largely dominant in the
Kédougou region, and is limited in the west by the eastern limit of
Niokolo-Koba National Park, and the locality of Bransan (n°7 in Fig. 1)
to the north. The other native rodent species (M. erythroleucus ,P. daltoni , A. niloticus in particular) are generally
present in low frequency at all localities. However, we can note their
particularly high proportions in villages of the Senegal river Valley
north of Bakel (locality n°1 in Fig. 1). Crocidura olivieri is
rarely absent from sampled localities (only 10/49), and regularly
(co)dominant in catches around Tambacounda and on both sides of the
Tambacounda-Kidira axis.