Beta-Diversity of Termite Assemblages Among Primary French Guiana Rain Forests Thomas Bourguignon 1 , Maurice Leponce 2 , and Yves Roisin 1,3 1 Evolutionary Biology and Ecology, CP 160/12, Universite ´ libre de Bruxelles, Avenue F.D. Roosevelt 50, 1050 Brussels, Belgium 2 Section of Biological Evaluation, Royal Belgian Institute of Natural Sciences, Rue Vautier 29, 1000 Brussels, Belgium ABSTRACT Termites are an important component of tropical rain forests, and have been included in many studies focusing on the influence of human disturbance. Their distribution among primary rain forest has, however, rarely been investigated. Here we studied the termite fauna in seven mostly undisturbed forest sites, representing several rain forest types. Overall, approximately 70 percent of species were soil-feeders and 25 percent were wood-feeders, the remaining 5 percent being classified here as litter-feeders. Termite species richness did not differ significantly among sites, but sites differed in termite abundance. The palm swamp and the low forest situated on the foothills of an inselberg, hosted different termite communities to the other sites. These two sites presented a singular physiognomy suggesting that forest type is an important factor influencing species composition. We found no correlation between termite species composition and distance between sites, highlighting that at the scale of our study (about 100 km), forest sites share a similar species pool. Key words: biodiversity; inselberg; Isoptera; Nouragues; tropical forest. SOCIAL INSECTS, ESPECIALLY ANTS AND TERMITES, ARE AMONG THE MOST ABUNDANT ANIMALS IN TROPICAL RAIN FORESTS, where they account for a large percentage of the total animal biomass (Martius 1994, Eggleton et al. 1996, Ellwood et al. 2002). While ants are conspic- uous, termites are more cryptic, but abound in wood and in the topsoil layers in which they constitute major organic matter decomposers (Holt & Lepage 2000, Sugimoto et al. 2000). De- spite their tremendous impact and abundance, the species richness of termites remains well below that of mega-diverse insect orders such as Diptera or Coleoptera, and the richest areas sampled to date comprise no more than 150 species of termites (Davies et al. 2003a). Following concern about the alarming destruction of tropical rain forests, many studies have focused on the variations of termite assemblages across forests subject to various degree of fragmenta- tion (DeSouza & Brown 1994, Davies 2002, Sena et al. 2003), or along a gradient of forest disturbance (Davies et al. 1999, Okwakol 2000, Eggleton et al. 2002, Bandeira et al. 2003, Jones et al. 2003, Ackerman et al. 2009). They generally conclude that termite diver- sity decreases along the sequence primary forest ! secondary for- est ! crops and cultivated fields—the latter stage generally being severely depauperate (Okwakol 2000). Differences in termite com- munities at a geographical scale among primary ecosystems are much less known, even though some studies highlighted faunal variation along altitudinal gradients (Gathorne-Hardy et al. 2001, Donovan et al. 2002) or according to the biogeographical location (review in Davies et al. 2003a). At a finer spatial scale, vertical strat- ification from soil to canopy level was recently demonstrated for wood-feeders (Roisin et al. 2006), as well as the influence of envi- ronmental factors such as the presence of palm trees (Davies 2002) or terrestrial bromeliads (Roisin & Leponce 2004). With few exceptions, such as the lichen-feeding Constricto- termes, termites feed at some point along the wood–soil decompo- sition gradient (Abe 1979, Tayasu et al. 1997). Studies in South America generally distinguish wood-, soil- and litter-feeders (e.g., Davies 2002, Davies et al. 2003a). A fourth category includ- ing species feeding at the interface between wood and soil is also recognized (e.g., Bandeira et al. 2003, da Cunha et al. 2006). Although the classification of species into distinct feeding groups necessarily involves arbitrary limits, these categories are ecologically relevant. Wood-feeding termites are more resilient to ecosystem perturbation than soil-feeding ones, which require more stable conditions (Wood et al. 1982, Eggleton et al. 2002, Jones et al. 2003). Tropical rain forest structure varies according to multiple fac- tors such as soil type and nutrient availability (Tuomisto & Ruokolainen 1994, Tuomisto & Poulsen 1996), topography (Aus- tin et al. 1996, Webb et al. 1999) or biotic factors such as abun- dance and diversity of lianas (Schnitzer & Bongers 2002). Rain forests are therefore heterogeneous and are often composed of a mosaic of more or less dissimilar forest patches. For example, in the Nouragues Nature Reserve (French Guiana), high mature forest with a fairly open understory is intermingled with low forest patches characterized by the abundance of lianas and a dense understory, and with forested swamps (Poncy et al. 2001). High environmental heterogeneity is often pinpointed as a key factor favoring the maintenance of a diverse animal community (e.g., Keller et al. 2009). In South America, seasonally flooded for- ests along the Amazon River host peculiar termite assemblages that differ considerably from those of terra firme forests (Mill 1982, Constantino 1992). French Guiana hosts one of the most diverse termite faunas, with over 100 species belonging to four families (Davies 2002, Bourguignon et al. 2009a), and as such is a suitable place to study termite b-diversity. In this study, we investigated termite species composition at seven sites spread over three localities in French Guiana, with the following objectives: (1) Wood-feeding termites have been suggested to be more resilient than soil-feeding termites Received 2 July 2010; revision accepted 30 August 2010. 3 Corresponding author; e-mail: yroisin@ulb.ac.be BIOTROPICA 43(4): 473–479 2011 10.1111/j.1744-7429.2010.00729.x r 2010 The Author(s) 473 Journal compilation r 2010 by The Association for Tropical Biology and Conservation