Turkish Journal of Zoology Turk J Zool (2019) 43: 437-456 http://journals.tubitak.gov.tr/zoology/ © TÜBİTAK Research Article doi:10.3906/zoo-1811-7 Comparative evaluation of taxonomic and functional diversities of leaf-litter ants of the Brazilian Atlantic Forest 1,2, 2 3 Elmo Borges Azevedo KOCH *, José Raimundo Maia dos SANTOS , Ivan Cardoso NASCIMENTO , 2,4 Jacques Hubert Charles DELABIE 1 Graduate Program in Ecology and Biomonitoring, Institute of Biology, Federal University of Bahia, Ondina Campus, Salvador, Bahia, Brazil 2 Laboratory of Myrmecology, CEPEC-CEPLAC, Ilhéus, Bahia, Brazil 3 Department of Biological Sciences, State University of the Southwest of Bahia (UESB), Jequié Campus, Jequié, Bahia, Brazil 4 Department of Agrarian and Environmental Sciences, State University of Santa Cruz, Ilhéus, Bahia, Brazil Received: 06.11.2018 Accepted/Published Online: 03.07.2019 Final Version: 02.09.2019 Abstract: The ant community living in leaf litter was assessed in 65 forest sites in the Brazilian Atlantic rainforest in the southern region of the state of Bahia, Brazil. In addition, we aimed to understand the patterns between taxonomic and functional diversities using two different resolutions of classification of ants into functional groups. We identified 364 ant species belonging to 68 genera in 10 subfamilies in 65 regions. Considering a more general functional classification, we identified a total of 13 functional ant groups, and 26 functional ant groups considering a more specific functional classification. The Atlantic Forest environments studied presented great taxonomic ant diversity. We observed that ant species richness and the number of functional groups are not closely related metrics, especially when considering a more general functional classification. Moreover, even when considering a more specific functional classification, the relationship with ant richness is only moderate. These results suggest that the number of species in a given group does not necessarily reflect the role played by that group within the environment. Integrating different biodiversity perspectives is crucial for the successful conservation of the Atlantic Forest ants. Key words: Diversity, Formicidae, functional groups, invertebrate conservation, tourist ant species 1. Introduction The Brazilian Atlantic Forest is one of the 35 biodiversity Efforts to understand the implications of changes in hotspots on the earth (Myers et al., 2000), which correspond biodiversity on ecosystems has shown that variations in to regions with high rates of biodiversity and endemism both species and functional diversity can lead to changes highly threatened by human activities (Myers et al., 2000; in environmental mechanisms, since several ecological Zachos and Habel, 2011). This biome originally covered processes are influenced by the number and nature of an area of 1,315,460 km2, corresponding to about 15% of species of a given location (Tilman, 2001). A better Brazil. Currently, it is estimated that only 8% to 12% of understanding of the patterns of changes in biodiversity and the original extension of the biome remains (Ribeiro et their functional consequences may allow a more accurate al., 2009; Fundação SOS Mata Atlântica, 2010, available prediction of responses, as well as the conservation of online at http://www.sosma.org.br), disseminated in a environmental processes (Brown and Heske, 1990; Larsen range of small fragments of very irregular sizes and shapes et al., 2005). The monitoring of biodiversity considering its (generally less than 50 ha) with a low rate of connectivity functional aspects allows for complementary traditional (Ribeiro et al., 2009, 2011). Nevertheless, this environment diversity indicators, such as species richness, diversity still represents the second largest tropical moist forest in indices, and abundance (Moretti et al., 2009; Gerish et al., the world (Ribeiro et al., 2011). 2011), since it allows researchers to evaluate the real effect Most conservation research has focused on providing of the species on ecosystem functioning (Tilman, 2001) data on vertebrates; for most invertebrate groups, independently of taxonomic determinations (Cummins, even basic information is scarce, especially in tropical 1974). environments (Fisher and Robertson, 2002). Among * Correspondence: [email protected] 437 This work is licensed under a Creative Commons Attribution 4.0 International License. KOCH et al. / Turk J Zool the priorities for studies of invertebrate conservation are The Atlantic Forest covers mostly low to medium elevation extensive geographical sampling using common protocols, areas (<1000 m a.s.l.) along the eastern Brazilian coastline, and studies focused on taxa and groups of recognized presenting hot and humid climate type AF (Köppen, functional importance in ecosystems (Lewinsohn et al., 1936), with annual temperatures ranging between 20 and 2005). Although insects are the dominant animal group 25 °C (IBGE, 2010, available online at http://www.ibge. in terms of abundance and diversity in most terrestrial gov.br), without having a true dry season (Oliveira-Filho ecosystems (Wilson, 1992), they are often neglected in and Fontes, 2000). conservation planning (Schuldt et al., 2009; McGeoch et 2.2. Ant sampling design al., 2011). We used an adaptation of the ALL protocol (Agosti Ants represent an important, abundant, and diverse and Alonso, 2000), commonly used in studies in the component in tropical forests (Kaspari, 1996, 2000; Atlantic Forest (Campiolo and Delabie, 2000). At each Delabie et al., 2000; del Toro et al., 2012), as well as in most site, we established a transect of approximately 2500 m diverse terrestrial ecosystems (Hölldobler and Wilson, for the ant survey, starting at least 100 m from the forest 1990; Underwood and Fisher, 2006). The litter that lies on edge. At each transect we marked 50 points set at 50-m the floor of tropical forests—a complex of leaves, branches, intervals; at each point, 1 m2 of leaf litter was collected. rotten material, and other biotic and mineral components In total, 50 leaf litter samples were collected at each site, (Kaspari and Weiser, 1999)—is a microhabitat that plays and mini-Winkler apparatuses were used to extract the a fundamental role in the diversity and survival of many ant fauna (Bestelmeyer et al., 2000). Since 50 samples of ant species (Kaspari, 1996; Theunis et al., 2005). The ants 1 m2 of leaf litter were taken in each of the 65 localities present in this environment—leaf-litter ants—display distributed over 6500 km2, our collection effort represents one of the highest levels of morphological, ecological, a total of 3250 m2 of forest leaf litter studied for their ants. and taxonomic diversity among ants (Delabie et al., The resulting biological material was fixed in alcohol 2000; Schmidt et al., 2013; Silva and Brandão, 2014), and and further screened at the laboratory. The ants were soil fauna is considered to be one of the new frontiers in separated from other arthropods, mounted, and identified biodiversity studies (Wilson, 1987; Agosti and Alonso, at the Myrmecology Laboratory of the Cocoa Research 2000; Delabie et al., 2015a). Center based on a reference collection of Formicidae of The present study investigated the taxonomic and the Atlantic Forest and through a query of the literature functional diversity of leaf-litter ants of the Brazilian (Bolton, 2018, available online at http://www.antcat.org/ Atlantic Forest biome in the state of Bahia. Due to the catalog) and a specific dichotomous key. relatively small surface (only 130 × 50 km) in which the 2.3. Ant functional groups classifications 65 localities of forest were intensively sampled for their Several studies carried out in different environments have leaf-litter ants, this study probably represents one of the used different classifications of functional groups for ants. most important efforts made to date to assess ant diversity There are some “classical” classifications (e.g., Andersen, in a single tropical region. Specifically, we addressed 1995; Delabie et al., 2000; Silva and Brandão, 2010), which the following questions: (1) What is the taxonomic and are commonly used; in some cases, adaptations of these functional diversity of leaf-litter ants for the region studied? classifications for specific cases or subgroups were also (2) Do ant assemblages that present greater taxonomic used (e.g., Delabie et al., 2000; Silva et al., 2015). diversity also possess a corresponding functional diversity? In recent years, a considerable amount of new (3) Is the number of functional groups a good predictor information about ant biology has been published. for ant richness? (4) Do the patterns found between However, such information has not yet been included in the taxonomic and functional diversity differ according to the functional group classification currently used. We believe level of functional classification used? that this classification should be constantly updated using this information. A second possibility is that it should at 2. Materials and methods least be checked to determine if this information changes 2.1. Study area the interpretation we have of the functional groups where The ant fauna of the forest litter was intensively sampled these species were included. between the years 1996 and 2002 in 65 sites of the Brazilian Partly due to this new knowledge, we have also observed Atlantic rainforest (Atlantic Forest) (hereafter designated that the various groupings on which the functional