Fishers' local ecological knowledge (LEK) is an additional tool to obtain information about cetaceans, regarding their local particularities, fishing interactions, and behavior. However, this knowledge could vary in depth of detail according to the level of interaction that fishers have with a specific species. This study investigated differences in small-scale fishers' LEK regarding the estuarine dolphin (Sotalia guianensis) in three Brazilian northeast coastal communities where fishing is practiced in estuarine lagoons and/or coastal waters and where dolphin-watching tourism varies from incipient to important. The fishers (N = 116) were asked about general characteristics of S. guianensis and their interactions with this dolphin during fishing activities. Compared to lagoon fishers, coastal fishers showed greater knowledge about the species but had more negative interactions with the dolphin during fishing activities. Coastal fishing not only offered the opportunity for fishers to observe a wider variety of the dolphin's behavior, but also implied direct contact with the dolphins, as they are bycaught in coastal gillnets. Besides complementing information that could be used for the management of cetaceans, this study shows that the type of environment most used by fishers also affects the accuracy of the information they provide. When designing studies to gather information on species and/or populations with the support of fishers, special consideration should be given to local particularities such as gear and habitats used within the fishing community.

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Aspidosperma pyrifolium (Apocynaceae) and Caesalpinia pyramidalis (Fabaceae) share the same habitat in the Brazilian Caatinga domain. In this paper, we investigate the intra and inter-species interactions between these two plants using spatial pattern analysis among cohorts. The results showed that the adult trees of each species present higher densities at distances shorter than 9 m to 12 m. However, due to seed dispersal via autochory, we expected a more aggregate density for C. pyramidalis than A. pyrifolium as the later disperses seeds through anemochory. Difference in spatial aggregation among cohorts was not observed and therefore the results contradict the expectations of the Janzen-Connell hypothesis. It is likely that this is associated with anthropogenic factors in the past such as fire, animal husbandry and logging. Using a bivariate analysis of the neighborhood density, we also confirmed the significant coexistence between the two species. This coexistence could be explained by the process of positive interspecific interactions, such as facilitation, which is common in semi-arid regions under stressful conditions. Padrão espacial e demografia de duas espécies arbóreas tropicais do bioma CaatingaResumo -Aspidosperma pyrifolium (Apocynaceae) e Caesalpinia pyramidalis (Fabaceae) compartilham o mesmo habitat no bioma Caatinga. Neste trabalho, investigamos as interações intra e interespecíficas por meio do padrão espacial entre coortes. Os resultados mostraram que as plantas adultas de cada espécie apresentam elevados níveis de densidade em curtas distâncias (9 m e 12 m). No entanto, devido à dispersão de sementes via autocoria, esperávamos uma densidade mais agregada para C. pyramidalis do que em A. pyrifolium, que tem dispersão anemocórica. Não foi observada diferença de agregação espacial entre coortes e, portanto, os resultados contradizem as expectativas da hipótese de Janzen-Connell. É provável que isto esteja associado a fatores antrópicos no passado, tais como incêndio, pecuária e exploração madeireira. Por meio da análise bivariada da densidade de vizinhos, foi confirmada a coexistência significativa das duas espécies. Isto pode ser explicado pelo processo de interações interespecíficas positivas, tais como a facilitação, que é comum em regiões semiáridas, sob condições estressantes.