RESUMEN
Abstract: We analyzed the overlap of the range of Pygochelidon melanoleuca in Brazil with active and planned hydropower plants in the country (current and future scenarios). We used the Random Forest, Maxent and Support Vector Machine algorithms to model the potential range of the species, which we then overlapped with the locations of active and planned hydropower plants in order to calculate how much the potential area of this species is and will be affected by them. Approximately 35% of active hydropower plants currently overlap with the potential distribution area of P. melanoleuca, and 44% of planned hydropower plants also coincide with this area. If the implementation of the planned hydropower plants occurs, the suitable habitat necessary for nesting and foraging of P. melanoleuca will be severely compromised.
Resumo: Analisamos a sobreposição da distribuição de Pygochelidon melanoleuca no Brasil com hidrelétricas ativas e planejadas no país (cenário atual e futuro). Utilizamos os algoritmos Random Forest, Maxent e Support Vector Machine para modelar a distribuição potencial da espécie, então sobrepomos com os locais das usinas hidrelétricas ativas e planejadas para calcular o quanto a área potencial desta espécie é e será afetada por elas. Aproximadamente 35% das hidrelétricas ativas estão sobrepostas com a área de distribuição potencial de P. melanoleuca e 44% das hidrelétricas planejadas coincidem com sua área. Se a implementação das hidrelétricas planejadas ocorrer, o habitat necessário para nidificação e forrageamento de P. melanoleuca estarão severamente comprometidos.
RESUMEN
This paper presents information about the species richness and abundance of orchid bees in the transitional area between the Cerrado and the Amazon Forest in the Xingu river basin. The males were collected in a forest fragment in the municipality of Ribeirão Cascalheira, northeast Mato Grosso state, Brazil, between 1 and 5 November 2011. Benzyl benzoate, 1.8 cineole, eugenol and vanillin were used as baits, to attract the bees using insect nets and methyl salicylate was used only in the bottle traps. A total of 168 males belonged to four of five Euglossini genera distributed among 16 species were recorded. The greatest species richness was registered in the genus Euglossa, however Eulaema nigrita, was the most abundant Euglossine species in the community. The species richness varied between the edge and the first point within the fragment. The males were more active between 10:00 and 11:00 h, and the 1.8 cineole was the most attractive substance. The fragment studied contained representative species richness of orchid bees in a region of widespread environmental heterogeneity, which is still largely unknown as regards its pollinators and deserves attention for the compilation of new inventories.
En este trabajo se presenta información sobre la riqueza de especies y abundancia de Euglossini en la zona de transición entre el Cerrado y la selva amazónica, en la cuenca del río Xingu. Las muestras se recogieron en un fragmento de bosque en el municipio de Ribeirão Cascalheira, nordeste de Mato Grosso, Brasil, entre el 1 y 5 de noviembre de 2011. Las sustancias puras de benzoato de bencilo, 1,8 cineol, eugenol y la vainillina fueron utilizadas como cebos para atraer los machos usando red de insectos aunque el salicilato de metilo se utilizó en trampas pasivas. Un total de 168 machos pertenecientes a cuatro géneros fueron registrados, distribuidos en 16 especies. La mayor riqueza de especies se registró en el género Euglossa, aunque Eulaema nigrita fue la especie más abundante en la comunidad. La riqueza de especies varió entre el borde y el primer punto dentro del fragmento. Los machos de abejas de orquídeas eran más activos entre 10:00-11:00 h, y el 1,8 cineol fue la sustancia pura más atractiva. El fragmento estudiado contenía un alto grado de riqueza de especies de abejas de orquídeas en una región de heterogeneidad ambiental extensa, que sigue siendo en gran parte desconocido con relación a su fauna de insectos polinizadores y merece la atención para la elaboración de nuevos inventarios.