Abstract Understanding how functionally similar species segregate resources to minimize competition is vital for predicting evolutionary factors and patterns of coexistence. We conducted a study in Mata de Itamacaoca, in the middle Munim River basin, Maranhão, northeastern Brazil, to characterize the functional morphology and trophic niches of five coexisting Characiform species in this area - including a recently described species, and to investigate whether their functional morphology is a key determinant of their trophic niches. Our analysis of functional morphology and diet, employing linear measurements to predict dietary specializations, showed that these species are predominantly generalist insectivores with a significant morphological overlap. This study underscores the influence of species' natural history on their ecological characteristics, contributing to more effective conservation strategies. coexistence Itamacaoca basin Maranhão Brazil diet specializations overlap characteristics strategies

Resumo Compreender como espécies funcionalmente semelhantes segregam recursos para minimizar a competição é vital para prever fatores evolutivos e padrões de coexistência. Conduzimos um estudo na Mata de Itamacaoca, na bacia do médio rio Munim, Maranhão, nordeste do Brasil, para caracterizar a morfologia funcional e nichos tróficos de cinco espécies de Characiformes coexistentes nesta área - incluindo uma espécie recentemente descrita, e investigar se a morfologia funcional dessas espécies é determinante para seus nichos tróficos. Nossa análise da morfologia funcional e da dieta, empregando medidas lineares para prever especializações alimentares, mostrou que essas espécies são predominantemente insetívoras generalistas com sobreposição morfológica significativa. Este estudo ressalta a influência da história natural das espécies em suas características ecológicas, contribuindo para estratégias de conservação mais eficazes. coexistência Itamacaoca Munim Maranhão Brasil descrita dieta alimentares significativa ecológicas eficazes

Freshwater crayfish are damaging invaders across southern Africa; however, monitoring techniques and efforts are disparate across the region as different sampling methods have been used. To develop a standard method for assessing redclaw crayfish Cherax quadricarinatus abundance, a survey was conducted to assess for differences in detection and catch per unit effort (CPUE) in Lake Kariba. Two sampling approaches were compared: opera traps baited with cooked maize meal historically used in crayfish surveys in Zimbabwe, and Promar collapsible traps baited with dry dog food, which have been used for assessments in South Africa and Swaziland. Baits were compared in the Barotse Floodplain in Zambia using the Promar trap. Detection probability (Pcapture) and CPUE were significantly lower for opera traps baited with cooked maize meal (Pcapture = 0.41; CPUE = 1.19 ± 0.24 ind.•trap -1•night -1) compared to the Promar traps baited with dry dog food (Pcapture = 0.67; CPUE = 4.53 ± 0.82 ind•trap -1•night -1). The Pcapture and CPUE for Promar traps baited with dog food (Pcapture = 0.89; CPUE = 4.29 ± 0.83 ind•trap-1•night -1) was significantly higher than for maize meal baited traps (Pcapture = 0.29; CPUE = 0.25 ± 0.17 ind•trap -1•night -1). Sex ratio and carapace length of crayfish sampled did not differ between sampling methods. Due to higher CPUE, the authors consider the Promar collapsible trap baited with dog food approach as the better method for determining crayfish population abundance and suggest that comparisons of abundance take this into consideration by applying conversion factors if different methods are applied.