Using local African communities' Ecological Knowledge to support scientific evidence of snake declines (Squamata: Serpentes)

Recent studies suggest that snakes are widely declining in at least three continents, and that this decline has targeted some species of tropical Nigeria, West Africa. To describe the possible interrelations among different causes and the boundary conditions to forecast snake decline, we explored local communities' Ecological Knowledge (EK) in this respect, i.e., that cumulative body of knowledge and beliefs concerning snakes, shared in the human community by cultural transmission, thus constituting the social memory. Here we describe a survey-based participatory approach to reinforce the scientific analyses of snake declines in the River Niger Delta, where significant snake declines have been detected over the last decade. We compared the results of two questionnaire-based surveys (the first in 1996-1997 and the second in 2011-2012) to farmers and hunters in a same set of 41 villages. The standardized questionnaire consisted of two parts: (i) a section with general questions on the personal attitude of the respondent toward snakes, and (ii) a section with three questions on perceived snake diversity, habitat, and current abundance around the villages of those interviewed. Three main patterns emerged: (1) the social shared role (value and dangerousness) of snakes in the rural communities was constant in the last 15 years; (2) some species were perceived as declining; and (3) the habitat - species relationships are slightly changed. The implications of these patterns are discussed, given that several aspects of the perceived changes in population abundances of targeted snakes were indeed consistent with herpetological scientific data from the field.