TY - JOUR
T1 - Food habits and ontogenetic dietary partitioning of American crocodiles in a tropical Pacific Island in Central America
AU - Balaguera-Reina, Sergio A.
AU - Venegas-Anaya, Miryam
AU - Beltrán-López, Valeria
AU - Cristancho, Alejandra
AU - Densmore, Llewellyn D.
N1 - Funding Information:
This research project was approved and supported by the Panamanian Environmental Agency (ANAM), the Panamanian National Secretariat of Science, Technology, and Innovation (SENACYT; project number ID APB11-004, permit number PNCOIBA08), and the Texas Tech University (animal care ACUC permit 10086–01) to capture, mark, and flush American crocodiles’ stomachs in Coiba National Park. All procedures followed ethical practices for animals approved by the Panamanian Environmental Agency and the Smithso-nian Tropical Research Institute (STRI). We thank AERONAVAL (Panama) for the economic and logistic support. We also thank Betzaida Rivera, Jhon Gaitán, Tatiana Rincón, Tatiana Niño, Italo Arbeláez, Andrés Sánchez, and Alejandro Morales for their help in the field and Nancy McIntyre, Richard Stevens, Richard Strauss, and David Ray for their comments to improve the manuscript. We thank Eduardo Amat, Rocio Garcia Cardenas, Juan del Rosario, Fernando Fernandez Castiblanca, Bibian Martínez, and Wilmer Munera for their help in the identification of species.
Publisher Copyright:
© 2018 The Authors.
PY - 2018/9
Y1 - 2018/9
N2 - Studies on food habits are fundamental to understanding the ecology of a species and its interactions with the community to which it belongs. Among crocodylians, diet affects a variety of biological, physiological, and behavioral characteristics. However, despite having one of the largest distributions across the Americas, some aspects of Crocodylus acutus’ natural history remain poorly studied, particularly in insular areas. We characterized American crocodiles’ food habits in Coiba Island, Panama, assessing ontogenetic dietary variation and dietary overlap by age group and size. We captured and collected stomach content samples from 49 individuals from four transects from March to December 2013. From these samples, we could taxonomically identify three phyla, four subphyla, eight classes, 11 orders, 17 families, 14 genera, and 12 species as prey items. However, not all samples could be identified to the lowest taxon (species), having most of them identified only to family level. Large juveniles had the largest proportion of prey items and subadults the largest proportion of gastroliths and vegetal content. Percent occurrence per major categories (insects, arachnids, crustaceans, fish, reptiles, birds, and mammals) showed crustaceans and insects as the most prominent groups of prey items on this island. Overlapping group analysis showed a reduction in the consumption of invertebrates (crustaceans and insects) as individuals aged. However, these items were the most common throughout all American crocodiles sampled. Dietary overlap analyses showed a likely ontogenetic dietary partitioning with high overlap (>60%) between small and large juveniles and low overlap (<30%) among small juveniles, subadults, and adults. To date, 71 species have been reported as prey items for American crocodiles. However, relying on prey items identified only to genus, we had at least 97 prey items. Thus, C. acutus can be defined as generalist with a broad spectrum of prey inhabiting all types of habitats and having all types of consumption classifications. Overall, American crocodiles inhabiting coastal areas present some differences in both dietary composition and structure with those dwelling inland and freshwater habitats as well as an interindividual diet variation, which reflects the plasticity and adaptability of C. acutus to a variety of conditions.
AB - Studies on food habits are fundamental to understanding the ecology of a species and its interactions with the community to which it belongs. Among crocodylians, diet affects a variety of biological, physiological, and behavioral characteristics. However, despite having one of the largest distributions across the Americas, some aspects of Crocodylus acutus’ natural history remain poorly studied, particularly in insular areas. We characterized American crocodiles’ food habits in Coiba Island, Panama, assessing ontogenetic dietary variation and dietary overlap by age group and size. We captured and collected stomach content samples from 49 individuals from four transects from March to December 2013. From these samples, we could taxonomically identify three phyla, four subphyla, eight classes, 11 orders, 17 families, 14 genera, and 12 species as prey items. However, not all samples could be identified to the lowest taxon (species), having most of them identified only to family level. Large juveniles had the largest proportion of prey items and subadults the largest proportion of gastroliths and vegetal content. Percent occurrence per major categories (insects, arachnids, crustaceans, fish, reptiles, birds, and mammals) showed crustaceans and insects as the most prominent groups of prey items on this island. Overlapping group analysis showed a reduction in the consumption of invertebrates (crustaceans and insects) as individuals aged. However, these items were the most common throughout all American crocodiles sampled. Dietary overlap analyses showed a likely ontogenetic dietary partitioning with high overlap (>60%) between small and large juveniles and low overlap (<30%) among small juveniles, subadults, and adults. To date, 71 species have been reported as prey items for American crocodiles. However, relying on prey items identified only to genus, we had at least 97 prey items. Thus, C. acutus can be defined as generalist with a broad spectrum of prey inhabiting all types of habitats and having all types of consumption classifications. Overall, American crocodiles inhabiting coastal areas present some differences in both dietary composition and structure with those dwelling inland and freshwater habitats as well as an interindividual diet variation, which reflects the plasticity and adaptability of C. acutus to a variety of conditions.
KW - community ecology
KW - crocodylians
KW - island
KW - mangrove ecosystem
KW - trophic networks
UR - http://www.scopus.com/inward/record.url?scp=85054859075&partnerID=8YFLogxK
U2 - 10.1002/ecs2.2393
DO - 10.1002/ecs2.2393
M3 - Article
AN - SCOPUS:85054859075
VL - 9
JO - Ecosphere
JF - Ecosphere
SN - 2150-8925
IS - 9
M1 - e02393
ER -