Sociobiology 61(2): 119-132 (June, 2014) DOI: 10.13102/sociobiology.v61i2.119-132 Sociobiology An international journal on social insects Research article - ANTS Ant Communities along a Gradient of Plant Succession in Mexican Tropical Coastal Dunes P Rojas1, C Fragoso1, WP Mackay2 1 - Instituto de Ecología A.C. (INECOL). Xalapa, México. 2 - University of Texas at El Paso, El Paso, USA. Article History Abstract Edited by Most of Mexican coastal dunes from the Gulf of Mexico have been severely disturbed by Kleber Del-Claro, UFU, Brazil human activities. In the state of Veracruz, the La Mancha Reserve is a very well preserved Received 12 March 2014 Initial acceptance 09 April 2014 coastal community of sand dunes, where plant successional gradients are determined Final acceptance 12 May 2014 by topography. In this study we assessed species richness, diversity and faunal composi- tion of ant assemblages in four plant physiognomies along a gradient of plant succes- Keywords sion: grassland, shrub, deciduous forest and subdeciduous forest. Using standardized Ant assemblages, species richness, and non-standardized sampling methods we found a total of 121 ant species distributed diversity, La Mancha, México in 41 genera and seven subfamilies. Grassland was the poorest site (21 species) and Corresponding author subdeciduous forest the richest (102 species). Seven species, with records in ≥10% of Patricia Rojas samples, accounted 40.8% of total species occurrences: Solenopsis molesta (21.6%), S. Instituto de Ecología A.C. (INECOL) geminata (19.5%), Azteca velox (14%), Brachymyrmex sp. 1LM (11.7%), Dorymyrmex Carretera Antigua a Coatepec 351 bicolor (11.2%), Camponotus planatus (11%) and Pheidole susannae (10.7%). Faunal El Haya, Xalapa 91070 composition between sites was highly different. Nearly 40% of all species were found in Veracruz, México. E-Mail: [email protected] a single site. In all sites but grassland we found high abundances of several species typi- cal of disturbed ecosystems, indicating high levels of disturbance. A species similarity analysis clustered forests in one group and grassland and shrub in another, both groups separated by more than 60% of dissimilarity. Similarity of ant assemblages suggests that deciduous and subdeciduous forests represent advanced stages of two different and independent successional paths. Introduction poorly studied. However, the importance of these ecosystems for conservation of ants has been recently recognized (Howe Ants are social insects with important ecological func- et al., 2010). Communities from temperate and tropical coastal tions. They influence ecosystems through soil bioturbation ecosystems are markedly different. In general, ant communi- (Lobry de Bruyn & Conacher, 1990), predation of inverte- ties from temperate marine coasts have a low number of spe- brates (Gotwald, 1995) and mutualistic interactions with hun- cies and, independently of the number of sites included in a dreds of plant species (Jolivet, 1996). Due to their high di- given locality, the number of species never surpass two dozen. versity, numerical and biomass dominance (Fittkau & Klinge, For example, Boomsma and De Vries (1980) in The Netherlands 1973, Brown, 2000) and sensitivity to environmental changes recorded only three species in sparsely vegetated sand dunes (Andersen, 1995), ants constitute an ideal group to inquire and grasslands, whereas studies in successional gradients from about patterns in community characterization. Coastal dunes pioneer vegetation to mature forests carried out in Finland are complex and very dynamic environments that have been (Gallé, 1991) and Spain (Ruano et al.,1995), recorded 19 and shaped by biological and physical processes like water and wind 24 species respectively. In temperate dunes, species richness, action (McLachlan, 1991). Its high environmental heteroge- abundance and equitability increases along vegetation suc- neity is determined by distinct landforms and different plant cession, with higher values being found in sites with a more communities (Martínez et al., 2004). dense plant cover (Boomsma & Van Loon, 1982; Ruano et al., Ant communities from coastal environments have been 1995). Positive correlations have also been observed between Open access journal: http://periodicos.uefs.br/ojs/index.php/sociobiology ISSN: 0361-6525 120 P Rojas et al - Ant communities in tropical coastal dunes composition of ant assemblages and a more complex habitat Material and methods (Boomsma & Van Loon, 1982). These attributes of ant as- semblages, however, are relatively independent of diversity Study area and composition of vegetation, suggesting that in temperate coastal systems, plant succession stages are not coordinated The study area is located at the Centro de Investiga- with successional stages of ant communities (Gallé, 1991). ciones Costeras La Mancha (CICOLMA) in the coast central In tropical coastal dunes the number of ant species is region of Veracruz State (96°22’40’’ W; 19°36’00’’ N) with more variable. Studies in comparable vegetation mosaics, re- an altitudinal range of 0-80 m elevation. The CICOLMA field corded from 22 to 92 species in Cuba (Fontenla, 1993, 1994), station covers a total area of 83 ha. The zone is geologically Mexico (Durou et al., 2002), and Brazil (Bonnet & Lopes, young, shaped by Miocene volcanic activity and by Quater- 1993; Texeira et al., 2005; Vargas et al., 2007; Cardoso et nary deposits (Geissert, 1999). The weather is characterized al., 2010). In these systems species richness varies between by an annual average temperature of 25°C and an annual pre- habitats, with higher values being found in more complex and cipitation of 1500 mm, with the large amount of rains (78%) heterogeneous habitats (Fontenla, 1993; Durou et al., 2002; occurring during the rainy season of June-September. Soils Vargas et al., 2007). Faunal composition is another attribute are unstructured luvic and calcaric arenosols (Travieso & of tropical coast ant assemblages that strongly varies with the Campos, 2006). type of vegetation (Fontenla, 1993; Cardoso et al., 2010) and Sampling sites were established on four different suc- plant cover (Dorou et al., 2002). cessional stages of coastal dune vegetation: grassland, shrub, Most of natural undisturbed coastal dunes of the Mexi- deciduous forest and subdeciduous forest (Fig 1). Grasslands can littoral zone of the Gulf of Mexico have disappeared due and shrubs are found in semi stabilized dunes, with grasslands to extensive farming management, human settlements and being found in upper dry parts of the dunes and shrubs on hu- touristic activities (Moreno-Casasola, 2006). However, the mid depressions, where water table is higher. Tropical forests state of Veracruz still harbors some well-preserved sites of grow over stabilized dunes with subdeciduous forests being coastal dunes that can enter inland up to 3 km. One of these established on flat sites or sites with level relief, and decidu- sites is found within the Ecological Reserve of the Centro de ous forests located on more steep sites (Moreno-Casasola & Investigaciones Costeras La Mancha (CICOLMA). In the Travieso, 2006). dunes of La Mancha environmental gradients related to the Grassland (G), (Fig 1A) - With a plant cover of nearly force of the wind, sand movement, and depth of water table 40%, this community includes grasses and short shrubs that (ultimate mediated by topography), determine the establish- alternate with open spaces of bare sand. Common species are ment of different plant communities (Moreno-Casasola & Trachypogon plumosus (Humb. & Bonpl. ex Willd.) Nees, Vázquez, 2006). In this zone the vegetation follows a succes- Andropogon glomeratus (Walter) B.S.P. and Chamaecrista sional gradient, from pioneer plants and grasslands growing chamaecristoides (Colladon) Greene (Moreno-Casasola & on the beach and young dunes, to deciduous and subdecidu- Travieso, 2006). ous tropical forests established on older dunes. This last com- munity constitutes the last remnant of this kind of forest in the Gulf of Mexico growing in sandy soils (Moreno-Casasola & Travieso, 2006). Several studies of ants have been conducted at La Mancha, including numerous aspects of plant-ant interactions (Rico-Gray, 1989, 1993; Mehltreter et al., 2003), evaluation of some invasive ants (Fragoso & Rojas, 2009), records in check- lists (Rojas 2001, 2011) and taxonomical studies (Mackay et al., 2004). So far, no studies characterize the complete ant community in any vegetation type of this site have been pu- blished. The main objective of our study was to describe the ant communities of La Mancha in four types of vegetation that represent a gradient of plant succession on coastal dunes. Communities were characterized considering species rich- ness, diversity, abundance and species composition. We hy- pothesized that richness and diversity would increase along the vegetation successional gradient; that each stage will have Fig 1. La Mancha plant physiognomies sampled in this study. different faunal composition, and that differences will be A − Grassland, B − Shrub, C − Deciduous forest, D − Subdecidu- higher between early and late successional stages. ous forest. Sociobiology 61(2): 119-132 (June, 2014) 121 Shrub (S), (Fig 1B) - Medium size (2-3 m high) closed 10cm diameter plastic Petri dish, deposited aboveground and canopy shrub with a plant cover of 80% and with some iso- left for 5 hours (from 10:00 to 15:00 h). Attracted ants were lated tress. Predominant species are shrubs Randia