5 research outputs found
Hemicryptophytes plant species as indicator of grassland state in semi-arid region: Case study of W Biosphere Reserve and its surroundings area in Benin (West Africa)
In semi-arid region managers are facing rapid degradation of grassland. There is a need to determine indicators to be used to detect early change occurring in the grassland for their sustainable management. Thereof, in this study, we explored the reliability of the use of hemicryptophytes as indicator of grassland state in semi-arid region within W Biosphere Reserve and surrounding areas (Benin). Plots of 10 m X 10 m were installed along a land use gradient (from communal lands to the protected area via the buffer zone) in three vegetation types for plant biomass harvesting and hemicryptophytes traits measurement. The hemicryptophyte density, biovolume, tussock size, contact frequency, contribution to total plant biomass and grassland grazing value were assessed and compared between land uses. Findings showed that hemicryptopyte traits were significantly different with the land use type. Hemicryptophyte biovolume and hemicryptophyte contribution were strongly correlated, respectively, with total biomass production and grazing value. The study highlights the relevance of hemicryptophyte as indicators of grassland state that could be used by grassland managers for grassland monitoring, restoration and sustainable use.Keywords: Grassland monitoring, hemicryptophyte traits, indicators, land us
GERMINATION OF SEEDS FROM EARLIER FRUITS OF BITTER AND SWEET AFRICAN BUSH MANGO TREES
Plant species are basic component of agro-biodiversity and a complex
situation created by their own ability to disperse; and the rapid
changes of land use and climate is endangering their efficient
conservation and use. In order to increase knowledge of bitter and
sweet African bush mango trees (ABMTs) ( Irvingia spp.: Irvingiaceae)
and support small-scale farmers in establishing uniform plantations,
germinability of earlier fruited trees was assessed. Germination rate
and speed, from both systems were analysed in order to differentiate
bitter and sweet bush mango trees and identify types of seeds suitable
to overcome the climatic hindrances for uniform plantations
establishment in the Dahomey Gap, a drier eco-region where savannah
reach the sea coast including Benin and Togo. Fresh seeds of both
bitter and sweet fruited trees, showed the highest growth performance
(98 - 100%). Seed germination speed significantly depended on the
drying level and the germination system (sunshine versus covered
condition). The speed was higher for fresh seeds in closed condition,
confirming bush mango seeds as typically recalcitrant, but not strictly
photoblastic. Results also demonstrated that bush mango seeds do not
require specific treatments for optimising germination. Germination did
not depend on mango tree type (bitter or sweet) and fresh seeds were
the best material for establishing viable and uniform plantations.Les plantes sont une composante essentielle de
l\u2019agrobiodiversit\ue9; leur habilet\ue9 \ue0 se propager
cr\ue9e une situation complexe et le changement rapide des
syst\ue8mes d\u2019utilisation des terres menace leur conservation
et utilisation. Afin d\u2019am\ue9liorer l\u2019\ue9tat de nos
connaissances sur les types amer et sucr\ue9 de manguiers sauvages
d\u2019Afrique ( Irvingia spp.: Irvingiaceae) et aider les petits
paysans \ue0 disposer de plantations uniformes, la germination des
fruits pr\ue9coces de Irvingia a \ue9t\ue9 \ue9valu\ue9e en
syst\ue8mes ouvert et ferm\ue9. Le taux et la vitesse de
germination dans ces deux milieux ont \ue9t\ue9 analys\ue9s afin
de diff\ue9rencier les arbres producteurs de fruits versus
sucr\ue9s et d\u2019identifier les types de semences qui sont
appropri\ue9s pour r\ue9duire les contraintes climatiques pour
l\u2019\ue9tablissement des plantations uniformes dans le
Dahomey-Gap, une \ue9cor\ue9gion s\ue8che o\uf9 la savane
atteint la c\uf4te, beaucoup plus au Benin et au Togo. Seul le niveau
de s\ue9chage influence significativement le taux de germination. Les
graines fraiches des deux types d\u2019arbres ont le taux de
germination le plus \ue9lev\ue9 (98 - 100 %). La vitesse de
germination d\ue9pend \ue0 la fois du taux de s\ue9chage et du
syst\ue8me de germination. La vitesse est plus \ue9lev\ue9e pour
les graines fraiches en syst\ue8me d\u2019ombrage, confirmant les
graines de mangues sauvages comme \ue9tant typiquement
r\ue9calcitrantes, mais non pas photoblastique strictes. Les
r\ue9sultats ont aussi montr\ue9 que les graines de mangues
sauvages ne n\ue9cessitent aucun traitement sp\ue9cifique pour
optimiser leur germination. Enfin l\u2019\ue9tude d\ue9montre que
la germination ne d\ue9pend pas du type d\u2019arbre de manguier
(arbres \ue0 fruits amers de ceux \ue0 fruits sucr\ue9s) et que
les graines fraiches sont les meilleurs mat\ue9riels pour
l\u2019\ue9tablissement des plantations viables et uniformes