Efeitos da distância entre iscas nas estimativas de abundância e riqueza de formigas em uma floresta de terra-firme na Amazônia Central

Abstract

RESUMOColetas com iscas são amplamente utilizadas para investigar a atividade de formigas de solo e vegetação e também podem ser empregadas para estimar o número de espécies e a abundância de formigas. Apesar de ser barata e fácil de implementar, a riqueza e abundância das formigas estimadas por iscas podem ser enviesadas por alguns fatores, como a distância entre iscas. Neste trabalho, avaliamos se a distância entre iscas altera as estimativas de abundância e riqueza de formigas e qual distância entre iscas resulta na melhor relação entre custo financeiro e número de espécies amostradas, objetivo da maioria dos relatórios de impacto ambiental. Amostramos 30 transectos de 100 m com distância entre iscas diferentes (2,5; 3,4; 5; 6,7; 10 e 20 m), distribuídos em uma área de 1 km 2 em uma floresta de terra-firme ao norte de Manaus. Independente da distância entre iscas, o número de espécies coletado a cada cinco iscas, foi aproximadamente 8, e a abundância média foi maior que 50 indivíduos. No entanto o número de espécies por isca foi maior em transectos com maior distância entre iscas. Transectos com distância entre iscas de 10 e 20 m, coletaram 50% mais espécies por isca que transectos com iscas distantes a 2,5 e 3,4 m entre si. Nossos resultados sugerem que nesta área, a amostragem mais eficiente desse método de coleta seria distribuir 450 iscas a cada 10 m ou 20 m no solo da floresta. PALAVRAS-CHAVE: conservação, curva de acumulação de espécies, esforço de coleta, floresta tropical, invertebrados de solo, relatório de impacto ambiental. Effects of bait spacing on ant abundance and richness in one forest at Central Amazonia ABSTRACTBaits are widely used to investigate the activity of terrestrial and arboreal ants, but also can be used to estimate the ant abundance and species richness. Despite the fact that baiting are cheap and easy to implement, many factors, such as the distance between baits, may influence the estimate of ant species richness and abundance. In this study, we evaluated the effects of bait spacing on abundance and the number of ant species. We also demonstrate which distance between baits showed the best relationship between costs and number of ant species sampled. We sampled 30 transects of 100 m with bait spacing ranging from 2.5 to 20 m, spread over 1 km 2 of a "terra-firme" forest situated at North of Manaus. The bait spacing did not affect the ant diversity estimative. Regardless bait spacing, the number of species collected every five baits was around 8, and the average abundance was approximately 50 individuals. However the number of species per bait was higher in transects with larger bait spacing. Transects with bait spacing of 10 m and 20 m, collected 50% more species than transects with baits placed 2.5 m and 3.4 m apart. Our results suggest that at this forest, the most efficient sampling design using only baits would be place 450 baits every 10 m or 20 m at the forest floor.

Ant species (Hymenoptera, Formicidae) of forest fragments and urban areas in a Meridional Amazonian landscape

“…This study shows that ant communities from disturbed forest areas are similar to those found in other Neotropical areas with some degree of environmental degradation. On the other hand, even with the subsampling approach of this study and the environmental degradation of forest areas highlighted by the presence of tramp ants in the fragments, species diversity of these areas is similar to others studies conducted with baits in relatively well preserved regions of the Amazonian rainforest (Baccaro et al 2011. In this sense, this work fills important gaps in the distribution of many ant species both native and exotic due to a lack of systematic surveys of biodiversity in the meridional Amazon.…”

“…the previously defined areas, such as buildings, wood piles, construction waste, vegetation, rotting logs, twigs, and litter. Although the distance between the bait may have generated a subsampling (see Baccaro et al 2011), the complementarity of the methods may have minimized this problem, which is corroborated by the high diversity of ants sampled in this study.…”

Composition and Diversity of Ant Species into Leaf Litter of Two Fragments of a Semi-Deciduous Seasonal Forest in the Atlantic Forest Biome in Barra do Choça, Bahia, Brazil

“…Analyses of the accumulated richness curves indicated complete sampling of the ant fauna was not achieved in either type of trap, as none of the curves approached the asymptote. Thus, projected richness values were always greater than observed values (Table 1), which is the usual situation in biodiversity studies in the tropics (Martins & Santos, 1999;Feitosa & Ribeiro, 2005;Baccaro et al, 2011;Braga et al, 2010;Leponce et al, 2004;Delabie et al, 2007), since many rare species continue to be encountered even after extremely intense sampling efforts (Santos, 2003).…”

Worker morphology of the ant Gnamptogenys striatula Mayr (Formicidae, Ectatomminae) in different landscapes from the Atlantic Forest domain

“…A distance of 20m between the sampling points was used for all of the collection methods to avoid pseudoreplication (Baccaro et al, 2011). Four ecosystem types with distinct phytophysiognomies were selected ( Table 1).…”