Caloric content of leaves of five tree species from the riparian vegetation in a forest fragment from South Brazil

Abstract

Aim: The measurement of the caloric content evidences the amount of energy that remains in the leaf and that can be released to the aquatic trophic chain. We assessed the energy content of leaves from five riparian tree species of a forest fragment in south Brazil and analyzed whether leaf caloric content varied between leaf species and between seasons (dry and wet). The studied sites are located in Northwest of Paraná State, inside a Semi-Deciduous Forest fragment beside two headwater streams. Methods Sampling sites were located along the riparian vegetation of these two water bodies, and due to its proximity and absence of statistical differences of caloric values, analyzed as one compartment. Results Caloric content varied significantly among species and among all pairs of species, with exception of Nectandra cuspidata Ness and Calophyllum brasiliensis Cambess. Two species presented significant differences between seasons, Sloanea guianensis (Aubl.) Ben and Calophyllum brasiliensis Cambess. Conclusions The absence of significant seasonal differences of energy content for some species may be due to the characteristics of the tropical forest, in which temperature did not varied dramatically between seasons. However, the energy differed between species and seasons for some species, emphasizing the necessity of a preliminary inspection of energy content, before tracing energy fluxes instead of using a single value to all species from riparian vegetation.

Efeito da cobertura de dossel sobre a comunidade de Odonata (insecta) em igarapés na região de Santarém-Belterra (PA)

“…Com o aumento de aproximadamente 10% na cobertura de dossel há um aumento de aproximadamente dois indivíduos e uma espécie de Zygoptera. Dadas as exigências ecofisiológicas de Odonata, vários estudos têm demonstrado que a diversidade desse grupo é afetada em uma escala local principalmente por modificações da vegetação (SAMWAYS et al, 1996;CARVALHO et al, 2013;OLIVEIRA-JUNIOR et al, 2017).…”

“…Indivíduos da subordem Anisoptera geralmente são beneficiados pela alteração das áreas naturais em função de suas habilidades de termorregulação, pois tendem a apresentar mecanismos homeostáticos mais eficientes e maior mobilidade, tolerando condições ambientais mais diversificadas (HUGHES et al, 2000;TSCHARNTKE et al, 2002). A riqueza desta subordem em ambientes alterados também pode ter sido provocada pela proximidade de ambientes lênticos, possibilitando que os insetos dispersassem para os igarapés amostrados nesta categoria (MARCO et al, 1998;CARVALHO et al, 1998).…”