PLANT DIVERSITY AND ECOLOGICAL CHARACTERISTICS OF THE VEGETATION OF THE DOSSO PARTIAL WILDLIFE RESERVE

The Dosso Partial Wildlife Reserve is a protected area dedicated to the conservation of wildlife
and its habitat in order to limit human pressure on W National Park in Niger. The objective of
this study is to assess the current state of the floristic diversity of the Dosso Partial Wildlife
Reserve and its organization into plant communities in relation to environmental factors.
Specifically, the objectives are to: 1) determine the composition and floristic diversity; 2)
identify and characterize the plant communities; and 3) understand the environmental factor(s)
structuring the distribution of the plant communities. A forest inventory was conducted using
stratified sampling, allowing for the assessment of species richness and diversity within land
cover units. A total of 195 plots were surveyed and randomly distributed while respecting the
criterion of floristic homogeneity. The DCA multivariate analysis method was used to
discriminate between plant communities and the environmental factors responsible for their
distribution. In total, 181 species (44 woody and 137 herbaceous) distributed across 136 genera
and 50 families were analyzed, with the most abundant families being Poaceae and Fabaceae.
Three major plant communities were identified: the Combretum nigricans and Trianthema
portulacastrum community of the Tiger Bushes (with 3 subgroups), the Acacia macrostachya
and Justicia insolaris community of the Savannas (with 3 subgroups), and the Anogeissus
leocarpus and Borreria scabra agroecosystem community (with 4 subgroups). Geomorphology
was the primary factor influencing their discrimination. Furthermore, factors such as soil type,
surface conditions (sedimentation crust, biological and erosional crust), and land use also
contribute to the structuring of plant communities. Analysis of the biological types of the
community shows a dominance of therophytes (51.6%) followed by microphanerophytes
(27.4%) in the unweighted spectrum. In the weighted spectrum, microphanerophytes are the
most dominant (48.3%), followed by therophytes (25.3%). The phytogeographic distribution
shows that African species are the most dominant in the unweighted spectrum (51.6%) and
represent 73.6% of the weighted spectrum. The least dominant phytogeographic types are
represented by Indian, Afro-Malagasy, Afro-Neotropical, and cosmopolitan species (1%) in the
unweighted spectrum and less than 1% in the weighted spectrum. This study has highlighted
the plant composition of this reserve adjacent to the W National Park, which plays a strategic
ecological barrier role and thus preserves biological diversity.