Tropical forests such as the Atlantic Forest are under constant threats from the impact of human activities, mostly being caused by the loss of native forest areas for other land uses. This study aimed to evaluate the effect of changes in land use for pasture and cacao cultivation on the richness and composition of Odonata assemblages in comparison to native forest areas. We also evaluated the species as possible indicators of these different land uses. In total, 64 streams were sampled in southern Bahia, Brazil. A total of 84 species were recorded. The results indicated that changes in land use modify the richness and composition of Odonata assemblages. Regarding composition, our results indicated a difference among the assemblages in the three land use areas and that the native areas maintain more stable assemblages. According to the indicator species analysis, 13 species were recorded as possible bioindicators for different land uses. Changes in aquatic ecosystems and their surroundings caused by different land uses a select group of different species groups, modifying Odonata diversity among these areas. Notably, land uses that maintain a certain integrity of the environment, as in the case of cacao cultivation, are the best alternatives for conserving Odonata biodiversity in comparison with pasture.
In the south of Bahia state, a large part of the native Atlantic Forest areas has been modified for the cultivation of cocoa (Theobroma cacao). These crops are cultivated under the shade of the canopy of native trees, a system locally known as the “cabruca” agroforestry system. This study aimed to evaluate the relationship of Odonata assemblages (adults and larvae) in cocoa farming areas and to identify the relationships of these species with local and spatial environmental variables of the monitored sites. Altogether, adult and larvae were sampled at 22 sites. Physical and physicochemical water variables were recorded for each site. A total of 1336 dragonflies were collected, of which 20 were Zygoptera species and 30 were adult Anisoptera representatives. The different life stages were related to environmental variables such as conductivity, watercourse channel width, and dissolved oxygen. The space predictors were also associated with the assemblages, mainly for adults. The present study identified that cabruca areas maintain a great diversity of dragonflies, including species that are considered to be forest specialists and more sensitive to landscape changes. The characteristics of this cropping system are considered to be favorable for the conservation of the biodiversity of the Atlantic Forest.
Leptagrion acutum Santos, 1961 is endemic to Brazil and, since 2003, listed as Critically Endangered in the Red Book of Threatened Brazilian Fauna. In this study, L. acutum is recorded for the first time from the state of Bahia, expanding known occurrences of this species to northern areas of the Atlantic Forest. Three males were collected in the Veracel Station Private Reserve of Natural Heritage. Information concerning distributional records of rare or endangered species is essential because it can add to species’ occurrence records and assist in future Red List assessments.
The genus Leptagrion Selys, 1876 comprises 17 described species. Of these species, only eight have their immature stage described. In this work, we describe the last instar larva of Leptagrion dispar Selys, 1876. The specimens were collected in areas of Atlantic Forest in three municipalities of the southern region of Bahia, Brazil, in phytotelmata habitats of bromeliads. Larvae were described based on the characteristics of the preserved F-0 larvae and exuviae of the emerged specimens in the laboratory. We added information about the habitats where the specimens were found. We extended occurrence records to other regions of the state of Bahia and presented a comparative table with morphological characteristics of all Leptagrion larvae already described.
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