Metabolic Theory of Ecology and diversity of continental zooplankton in Brazil - doi: 10.4025/actascibiolsci.v34i1.9087

Several ecological hypotheses try to explain geographical patterns in biodiversity. The Metabolic Theory of Ecology (MTE) predicts that temperature is the main determinant of richness patterns for ectothermic organisms and that the relationship between richness (lnS) and temperature (1/kT) is a linear relationship with angular coefficient (b) near -0.65. This study tested the MTE for continental zooplankton diversity in 63 lakes in Brazil. Copepoda, Cladocera and Rotifera, as well as the three groups combined, showed different patterns from that predicted by MTE, with b values equal to 0.871, 0.516, 0.720 and 0.901, respectively. Temperature explains 12.7% of the richness of Copepoda, 5.3% of Cladocera, 6.7% of Rotifera, and 11.4% of all zooplankton groups together. Several studies have shown that the MTE does not apply to many terrestrial groups, perhaps because the model does not consider variances generated by other factors such as environmental spatial range, body size and other variables. The present study confirms this point of view, expanding it to continental aquatic invertebrates as well. macroecology; biodiversity; Copepoda; Cladocera; Rotífera; temperature gradients

Fishfauna trophic structure across longitudinal gradient of Salto Caxias Reservoir (Iguaçu River state of Paraná Brazil) in the third year after dam - DOI: 10.4025/actascibiolsci.v27i1.1362 / Estrutura trófica da ictiofauna, ao longo do gradiente longitudinal do reservatório de Salto Caxias (rio Iguaçu, Paraná, Brasil), no terceiro ano após o represamento - DOI: 10.4025/actascibiolsci.v27i1.1362

This study aims at evaluating the fishfauna trophic structure across the longitudinal gradient of Salto Caxias reservoir, in the third year after its dam (post 3). The data obtained were compared with the previous ones (pre and post 1) to verify if the species that altered their diets in the initial phase of the dam, returned to the same food resources offered by natural environment. S(tomachal) contents of 1527 fishes were analyzed, using the volumetric method. In general, fishes presented a great diversity of food items in their diets, usually with a predominant resource kind. Thus, the fishfauna was synthetized in eight trophic guilds. The detrivore and piscivore species did not alter their feeding habit across spatial gradient considerably). (A montanteUpstream, all the trophic guilds were equally distributed compared to the other sites. Comparing pre and post 1 periods with the post 3 results showed that few species returned to their original trophic habit

Objetivou-se, neste estudo, avaliar a estrutura trófica da ictiofauna, ao longo do gradiente longitudinal do reservatório de Salto Caxias, no terceiro ano após seu represamento (pós 3). Compararam-se os dados obtidos neste trabalho com dados anteriores (pré e pós 1), a fim de verificar se as espécies que alteraram suas dietas no início do represamento voltaram a utilizar os mesmos recursos alimentares oferecidos no ambiente natural. Foram analisados conteúdos estomacais de 1527 exemplares pelo método volumétrico. A maioria das espécies apresentou dietas compostas por grande diversidade de itens alimentares, predominando, geralmente, um tipo de recurso. A ictiofauna foi organizada em oito guildas tróficas. As espécies detritívoras e piscívoras não alteraram consideravelmente seu hábito alimentar ao longo do gradiente espacial. A montante, todas as guildas estiveram distribuídas em proporção mais semelhante do que nos demais locais. Comparando-se os períodos de pré e pós 1 com o pós 3, verifica-se que poucas espécies retomaram seu hábito alimentar original