Evaluation of three methods for sampling ground-dwelling Ants in the Brazilian Cerrado

Abstract

Avaliação de Três Métodos para Amostragem de Formigas do Solo no Cerrado BrasileiroRESUMO -Poucos estudos avaliaram a efi ciência de métodos para a coleta de formigas, especialmente em regiões com fi sionomias vegetais bastante variáveis como a do Cerrado. Neste trabalho, foram comparados três métodos para a coleta de formigas do solo: armadilhas de solo, iscas de sardinha e o extrator de serapilheira de Winkler, com o objetivo de determinar o mais apropriado para caracterizar as assembléias de formigas associadas a diferentes tipos de vegetação. Mais espécies foram coletadas com armadilhas de solo e com o extrator de Winkler do que com iscas. As armadilhas de solo coletaram mais espécies nas fi sionomias de cerrado (savânicas), particularmente naquelas com pobre cobertura de serapilheira, enquanto o extrator de Winkler foi mais efi ciente nas fi sionomias fl orestais, com exceção daquela sujeita a inundações periódicas. Houve baixa similaridade na composição de espécies entre as fi sionomias de cerrado e fl orestais, e esse padrão foi observado com qualquer dos três métodos de coleta. Portanto, mesmo o uso de um único método pode ser sufi ciente em estudos que comparam condições ou hábitats bastante distintos. Entretanto, se o propósito da amostragem for produzir um inventário mais completo, sugerimos o uso de uma combinação de métodos, em particular as armadilhas de solo e o extrator de Winkler. Desse modo, o Protocolo para Amostragem de Formigas da Serapilheira (ALL Protocol) parece ser adequado para a amostragem de formigas na ameaçada região do Bioma Cerrado. PALAVRAS-CHAVE: Inventário de formigas, isca, Formicidae, armadilha de solo, extrator de Winkler ABSTRACT -Few studies have evaluated the effi ciency of methods for sampling ants, especially in regions with highly variable vegetation physiognomies such as the Cerrado region of central Brazil. Here we compared three methods to collect ground-dwelling ants: pitfall traps, sardine baits, and the Winkler litter extractor. Our aim was to determine which method would be most appropriate to characterize the ant assemblages inhabiting different vegetation types. More species were collected with pitfall traps and with the Winkler extractor than with sardine baits. Pitfall traps collected more species in the cerrado (savanna) physiognomies, particularly in those with a poor litter cover, whereas the Winlker extractor was more effi cient in the forest physiognomies, except the one subject to periodic inundations. There was a low similarity in species composition between forest and cerrado physiognomies, and this pattern was detected regardless of the method used to sampling ants. Therefore, even the use of a single, relatively selective method of collection can be enough for studies comparing highly distinct habitats and/or conditions. However, if the purpose of the sampling is to produce a more thoroughly inventory of the ant fauna, we suggest the use of a combination of methods, particularly pitfall traps and the Winkler extractor. Therefore, the Ants of the Le...

Patterns of diversity and abundance of fungus-growing ants (Formicidae: Attini) in areas of the Brazilian Cerrado

“…We surveyed ants in two upland forest habitats: the cerradão and the semi-deciduous forest, whereas LEAL & OLIVEIRA (2000) worked closer to the valley, in the gallery forest, where occasional flooding may limit the establishment of ant nests on the ground (cf. LOPES & VASCONCELOS 2008). Nevertheless, both studies indicate that the density of attine nests in the Brazilian Cerrado is relatively high.…”

A comparison between time of exposure, number of pitfall traps and the sampling cost to capture ground-dwelling poneromorph ants (Hymenoptera: Formicidae)

“…they use metrics related to species richness or composition (Fisher, 1999;Delabie et al, 2000;Tista & Fildler, 2010). As a result, most of the investigations on ant sampling protocols were also based on these metrics (Olson, 1991;Bestelmeyr et al, 2000;Lopes & Vasconcelos, 2008). More recent sampling protocol approaches have included ecological responses and environmental variables to evaluate the efficiency of the collection techniques .…”

Simple does not mean poor: grasslands and forests harbor similar ant species richness and distinct composition in highlands of southern Brazil

“…The great number of new ant species in "Planalto Serrano" recorded here mainly is a result of this lack of knowledge, but also can be related to the complementarity of our sampling effort. The combination of pitfalls and leaf litter collection on the ground is strongly advised for biodiversity assessments (Alonso & Agosti 2000, Bestelmeyer et al 2000, King & Porter 2005, Lopes & Vasconcelos 2008, since the first method catch larger and more active species (Sabu et al 2011), while the second is efficient to sample smaller and less active ants, including cryptic species (Fisher 1999). Finally, our sampling effort in grasslands sites, a poorly surveyed physiognomy until now in Santa Catarina, is another important source of those new records, a trend that is increasingly highlighted in other grasslands surveys of South Brazil recently published (Pinheiro et al 2010, Rosado et al 2012, Dröse et al 2017, Franco & Feitosa 2018.…”