Indigenous knowledge is unevenly distributed. Individual knowledge level may be affected by many factors such as gender, age, ethnicity, profession, religious and cultural beliefs, abundance and usefulness of the species. This study documents indigenous knowledge of herbaceous and woody plant species of farmers and herders in southwestern Niger. Specifically, we examine the effects of age, gender, and ethnicity on knowledge of local vegetation. Results from the study showed that on average a higher proportion of woody species was identified by the respondents compared to herbaceous species. Both gender and ethnicity had a significant effect on the identification of herbaceous species but no effect on identification of woody species. Respondents in lower age group (10 to 30 years) identified lower number of species compared to other age classes. There seems to be a curvilinear relationship between age of respondents and number of plant species identified. Results from this study reaffirm the uneven distribution of indigenous knowledge within a given area due to social factors. The main challenge is how to incorporate these social differences in knowledge of native plant species into sustainable management and conservation of community natural resources.

Knowledge pertaining to local plant species in West African Sahel has been poorly documented despite the central role local vegetation plays in the everyday lives of the rural people. An ethnobotanical study was conducted between April and November 2005 to document knowledge and uses of local herbaceous and woody species by the agropastoralists in South-western Niger. One hundred and twenty three voucher reference samples were collected consisting of 87 and 36 herbaceous and woody species, respectively. The voucher specimens were used for individual interviews of the agropastoralists, guided by a semi-structured questionnaire. In each interview session, an interviewee was shown voucher reference samples and was asked to identify each of them. For each plant species identified, questions were asked about its utilization and the plant part(s) being used. Major uses of local plant species are for traditional medicine, human consumption, animal feed, household construction and firewood. Mean use value of woody species was significantly higher for all use categories (p < 0.001) than for the herbaceous species. These results confirm that "apparent" plants, perennial woody species, are used by the agropastoral communities more intensively than the "non-apparent" short life cycle herbaceous species.