The first step employed in the data analysis calculating the informant consensus factor (ICF) [12 ]. ICF values will be low (near 0) if plants are chosen randomly, or if informants do not exchange information about their use. Values will be high (near 1) if there is a well-defined selection criterion in the community and/or if information is exchanged between informants.
The ICF is calculated as follows: number of use citations in each category (n
ur) minus the number of species used (n
t), divided by the number of use citations in each category minus one:
All citations were placed into one of 14 categories: undefined pains or illnesses; skin and subcutaneous tissues; diseases of the endocrine glands, metabolism, and nutrition; blood and hematopoietic organs; skeletal, muscle, and connective tissues; infectious and parasite-related diseases; neoplasies; problems of the circulatory system; problems of the digestive system; problems of the genitourinary system; problems of the nervous system; problems of the respiratory system; problems of the sensorial system – ear; and problems of the sensorial system – eye.
The use value (adapted from the proposal of Phillips et al. [13 (link)]), a quantitative method that demonstrates the relative importance of species known locally, was also calculated:
UV = ΣU/n
where: UV = use value of a species; U = number of citations per species; n = number of informants
All of the material collected was processed, identified with the aid of specialists, and subsequently deposited in the PEUFR herbarium of the Biology Department of the Federal Rural University of Pernambuco. All material was collected with the help of local informants.