DOI: 10.15468/r2w2b6
title: Inventory of the orchid plants species in the Biosphere Reserve of Pendjari and surround areas in North West Benin

description: The effectiveness of the protected areas to guarantee future conservation of several plant species remains questionable. This study was carried out in the Biosphere Reserve of Pendjari (BRP) and surrounding unprotected areas to assess the efficiency of the reserve to conserve orchids. 
The vegetation map of the reserve was used to identify the three main vegetation types (savannas, woodlands and gallery forests). Both protected and unprotected areas were included in the study. In each vegetation type, points were randomly selected to serve as the starting point of a transect. In total, 65 transects of each at least 3 km long, were explored for the presence of orchid species. 
Three-person teams were used to intensively survey the trees and the vegetation on the ground for the presence of epiphytic and terrestrial orchids. One team member monitored the compass bearing of the transect, and the other two members scanned the vegetation for orchids. The presence of orchid species was confirmed by two team members. Sample plots were selected along the transects, based on the presence of orchid species. Rectangular plots (10 m x 50 m) were sampled in gallery forests (due to the linear shape of the gallery forests) and Square plots (30 m x 30 m) in savannas, woodlands and fallows. At least 25 plots were sampled per vegetation type, and 90 plots in total (with 52 plots in protected areas and 38 in unprotected areas).
The species and number of individuals of all orchid species (terrestrial and epiphytic) and the host trees of epiphytic orchids were recorded within each plot. The dominant plant species of tree and shrub layers were recorded. Simultaneously, field data on environmental variables were collected. These included the vegetation type, vegetation cover, soil texture, and the presence of rocks or stones. Signs of human disturbance, including agriculture, grazing, tree cutting and pruning, were also collected within the plots of unprotected areas. 
Herbarium specimens of all recorded orchid species were prepared and identified with the National flora and at the National Herbarium of Benin Republic. 
Only three epiphytic orchids (Calyptrochilum christyanum, Cyrtorchis arcuata and Plectrelminthus caudatus) were recorded and all in gallery forest of unprotected areas. Indeed, 67% and 58% of the orchid species were respectively only recorded in unprotected areas and gallery forest. There was no significant difference between the density of all recorded orchids in protected and unprotected areas. The conservation status of the studied zone had a significant effect on the densities of Nervilia kotschyi and Eulophia guineensis (p = 1.08e-06). 
This first effort to compile a reference list of the orchid species of the BRP showed that some orchid species were well represented within the protected area, but all of the epiphytic orchids were recorded from unprotected areas. A conservation gap can be assumed to exist for most epiphytic orchids recorded in the gallery forests of unprotected areas. Our results highlighted the need to redefine protective management strategies for orchid species in the BRP.