Univ. Sci. 2015, Vol. 20 (2): 229-245 doi: 10.11144/Javeriana.SC20-2.efna Freely available on line REVIEW ARTICLE Ecological functions of neotropical amphibians and reptiles: a review Cortés-Gomez AM1, Ruiz-Agudelo CA2 , Valencia-Aguilar A3, Ladle RJ4 Abstract Amphibians and reptiles (herps) are the most abundant and diverse vertebrate taxa in tropical ecosystems. Nevertheless, little is known about their role in maintaining and regulating ecosystem functions and, by extension, their potential value for supporting ecosystem services. Here, we review research on the ecological functions of Neotropical herps, in different sources (the bibliographic databases, book chapters, etc.). A total of 167 Neotropical herpetology studies published over the last four decades (1970 to 2014) were reviewed, providing information on more than 100 species that contribute to at least five categories of ecological functions: i) nutrient cycling; ii) bioturbation; iii) pollination; iv) seed dispersal, and; v) energy flow through ecosystems. We emphasize the need to expand the knowledge about ecological functions in Neotropical ecosystems and the mechanisms behind these, through the study of functional traits and analysis of ecological processes. Many of these functions provide key ecosystem services, such as biological pest control, seed dispersal and water quality. By knowing and understanding the functions that perform the herps in ecosystems, management plans for cultural landscapes, restoration or recovery projects of landscapes that involve aquatic and terrestrial systems, development of comprehensive plans and detailed conservation of species and ecosystems may be structured in a more appropriate way. Besides information gaps identified in this review, this contribution explores these issues in terms of better understanding of key questions in the study of ecosystem services and biodiversity and, also, of how these services are generated. Keywords: ecological functions; Neotropical region; ecosystems; reptiles; amphibians Edited by Alberto Acosta & Juan Carlos Salcedo-Reyes 1. Instituto de investigaciones en Recursos Biológicos Alexander von Introduction Humboldt, Laboratory of Conservation Genetics, Bogotá, Colombia. Herpetology Laboratory group, Biology Department, Universidad Amphibians and reptiles (herps) are an abundant and del Valle, Cali-Colombia. diverse component of many terrestrial and freshwater 2. Socioeconomic Manager. Conservation International Colombia. Bogotá-Colombia. ecosystems (Pough et al. 2004, Wells 2007, Collins 3. Instituto de Ciências Biológicas e da Saúde, Universidade Federal & Crump 2009), contributing to a diverse range of de Alagoas, Maceió 57051-090, Brasil. ecological functions (Young et al. 2004, Pough et al. 2004, 4. School of Geography and the Environment, Oxford University, Tyler et al. 2007, Wells 2007, Collins & Crump 2009). South Parks Road, Oxford, UK. However, they are much less studied than mammals Received: 17-07-2014 Accepted: 16-12-2014 (Kunz et al. 2011) and birds (Sekercioglu 2006, Whelan 26-02-2015 Published on line: et al. 2008), and scientific knowledge of their role in Citation: Cortéz-Gómez AM, Ruiz-Agudelo CA, Valencia-Aguilar A, Ladle RJ (2015) Ecological functions of neotropical amphibians ecosystem functioning is inconsistent and incomplete and reptiles: a review. Universitas Scientiarum 20(2): 229-245 (Urbina-Cardona 2008, Valencia-Aguilar et al. 2013). doi: 10.11144/Javeriana.SC20-2.efna Funding: The Conservation Leadership Programme and The generally low level of understanding regarding Conservation International Foundation. the roles that amphibians and reptiles play in ecosystems Electronic supplementary material: 2 is well illustrated by recent global studies (Bickford et Universitas Scientiarum, Journal of the Faculty of Sciences, Pontificia Universidad Javeriana, is licensed under the Creative Commons 2.5 of Colombia: Attribution - Noncommercial - No Derivative Works. 230 Ecological functions of amphibians and reptiles al. 2010, Hocking & Babbitt 2014). In response to Sources of information: Information was compiled evidence of rapid population declines of amphibians from the following sources: a) the bibliographic and reptiles worldwide (Rueda-Almonacid 1999, databases ISI WEB OF KNOWLEDGE, JSTOR, Gibbons et al. 2000, Lips et al. 2006, Reading et al. EBSCO, Science Direct, SCOPUS, and Google 2010), the International Union for the Conservation Scholar; b) Book chapters containing information of Nature (IUCN) carried out a global evaluation on Neotropical herps, and; c) Information provided and established criteria for determining the degree of by researchers. The search for information was threat to species of amphibians (Stuart et al. 2004), restricted with keywords and boolean connectors and a similar approach has been recently applied to (AND, OR). The following search words or terms reptiles (Böhm et al. 2012). Both studies identified were used: ecosystem function, ecological function, considerable data shortfalls, and these were particularly amphibian, reptile, tadpole, frog, toad, caecilian, apparent in the Neotropics - this region contain the salamander, lizard, snake, caiman, turtle, tortoise, role, largest number of amphibian species (49.2%) and bioturbation, decomposition, primary/secondary has suffered the highest rates of population decline production, sediment, consumption, nutrient cycling, (63.1%) (Stuart et al. 2004). nutrient flow, excretion, biological control, mosquito control, diet, predation, food habit, seed dispersal, seed The rapid and ongoing reduction of herp species ingestion, dispersers, frugivore, saurocory, pollination, richness worldwide has added urgency to efforts to foraging, and flower. understand the ecological roles that they play within ecosystems (Stuart et al. 2004, Lips et al. 2006, Compilation of information: Studies published over Connelly et al. 2011). The present work contributes the last four decades (1970 to 2014) and conducted in to this goal by providing a heuristic framework for the 32 countries were compiled into a data matrix and categorizing the functions of amphibians and reptiles analyzed by geographic region, year of publication, in Neotropical ecosystems. Previously we explored taxon (the study follows the current nomenclature the benefits to human society provided by elements for amphibians [Frost 2011] and reptiles [Uetz 2012]), of the neo-tropical herpetofauna (Valencia-Aguilar type of experiment (field or laboratory), year of the et al. 2013), here we explore their ecological roles; study and ecological function. acknowledging these are not mutually exclusive. It is essential to understand the functional processes Results and discussion behind the ecosystem services, this new contributions seek to contribute to these gaps in knowledge. We The total number of studies compiled resulted in 167, describe the research trends of the past 20 years, corresponding to: 67 % on amphibians and 33 % on identifying information gaps with respect to specific reptiles. Most studies (76 %) were based in South ecosystem functions and defining future investigation America, followed by Central America (14 %) and topics. As such, we aim to provide a robust database the Caribbean (10 %) (Figure 1). The vast majority platform for future studies on how herps affect (95%) of the sources were from electronic databases, ecosystem functioning in the Neotropics, and how 4.35% from libraries and less than 1% was provided they are responding to the ongoing environmental by researchers. changes within these ecosystems. Several studies of ecological functions of amphibians and reptiles were grouped into the Materials and methods following five categories: nutrient cycling, energy flow through trophic chains (as predator and prey), This study was based on a review of the literature about bioturbation, seed dispersal, and pollination (Table the ecological functions of amphibians and reptiles in 1), showing that the numbers of publications Neotropical ecosystems. Here, the term “function” on these themes have increased considerably in denotes the relation between the parts (taxa) and the recent years (Figure 2). Moreover, in the focus system, understood as the functions or roles that of the research, distinct historical trends were organisms perform within a system (Jax 2005). observed: in the 1970s, there was an emphasis on Universitas Scientiarum Vol. 20 (2): 229-245 www.javeriana.edu.co/scientiarum/ojs Cortéz-Gómez et al. 231 Fig. 1. Geographical origin of studies on Neotropical amphibians and reptiles. nutrient cycling and energy flow through trophic chains. Studies performed in the 1980s began to discuss the role of herps in seed dispersal and by Fig. 2. Number of studies from the last four decades on the 1990s, bioturbation arose as a distinct research the ecological functions of amphibians and reptiles in the Neotropics. topic. Finally, in the 2000s there was an increase in the number of studies focused on energy flow and seed dispersal. In this last decade some researchers lizards mainly) in the pollination of plants (mainly in also began discussing the role of reptiles (turtles and insular ecosystems). Table 1. Number of studies evaluating the ecological functions of amphibians and reptiles in Neotropical ecosystems. Ecological Number of studies Species number References function Amphibians Reptiles Amphibians Reptiles Nutrient cycling 3 1 2 1 Fitkau (1970), Beard et al. (2002, 2003), Connelly et al. (2011) Flecker et al. (1999), Arias