Terrestrial–aquatic trophic linkages support fish production in a tropical oligotrophic river
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Despite low in situ primary productivity, tropical oligotrophic rivers support highly diverse fish assemblages and productive fisheries. This raises the question, what energy sources support fish production in these ecosystems? We sampled fish and food resources in the floodplain of a nearly pristine, large, oligotrophic river in western Amazonia. We combined data from stomach contents and stable isotopes to test the hypothesis that floodplain forests sustain fisheries in tropical oligotrophic rivers. Analysis of stomach contents from > 800 specimens of 12 omnivorous fish species demonstrated that during the annual flood, forest plant matter dominated diets. Yet, our isotope mixing models estimated that arthropods from the forest canopy made a greater proportional contribution to fish biomass. Most of these arthropods are entirely terrestrial and, therefore, serve as trophic links between forests and fishes. Our results suggest that forest vegetation, particularly fruits, may provide much of the energy supporting metabolism and arthropods contribute significant amounts of protein for somatic growth. Moreover, the importance of terrestrial arthropods in support of fish biomass in oligotrophic rivers depends on interactions between riparian vegetation, terrestrial arthropods and flood pulse dynamics affecting accessibility of arthropods to fishes. The apparent paradox of high fish diversity in an oligotrophic river with low primary productivity may be explained, at least partially, by dynamic terrestrial–aquatic trophic linkages. This study further emphasizes the importance of seasonally flooded forests for sustaining fisheries in the Amazon.
KeywordsFlood pulse Flooded forest Food web Inland fisheries Trophic subsidy
We thank field assistants (J. J. Patarroyo, L. Cruz, I. López, L. Bravo, E. Tanimuka, J. J. Acevedo, B. Mejía, L. Tanimuka, A. Carevilla, and F. Yucuna) and colleagues in Colombia who provided logistic support and access to laboratory facilities (Francis and Edwin Palacios, Conservación Internacional; Santiago Duque, Universidad Nacional de Colombia, Sede Leticia; and Pablo Stevenson, Universidad de los Andes). This research was funded by the Wildlife Conservation Society’s Research Fellowship Program (to SBC) and the estate of Carolyn Wierichs Kelso. We thank indigenous leaders of the Resguardo Yaigojé-Apaporis (Puerto Ňumi and Bocas de Taraira) for granting access to their territories. Research permit was granted by the Instituto Colombiano de Agricultura, Colombia. All applicable institutional and/or national guidelines for the care and use of animals were followed.
Author contribution statement
SBC and KW designed the study. SBC collected data and conducted analyses. SBC and KW wrote the manuscript.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
The data used in this publication will be archived at the Dryad Digital Repository.
- Adis J, Erwin TL, Battirola LD, Ketelhut SM (2010) The importance of Amazonian floodplain forests for animal biodiversity: Beetles in canopies of floodplain and upland forests. In: Junk WJ, Piedade MTF, Wittmann F, Shongart J, Parolin P (eds) Amazonian floodplain forests: ecophysiology, biodiversity and sustainable management. Springer, Dordrecht, pp 313–325CrossRefGoogle Scholar
- Arantes CC, Winemiller KO, Petrere M, Castello L, Freitas CE, Hess LL (2017) Relationships between forest cover and fish diversity in the Amazon River floodplain. J Appl Ecol (in Press)Google Scholar
- Barthem R, Goulding M (2007) An Unexpected ecosystem: the Amazon as revealed by fisheries. Asociación para la Conservación de la Cuenca Amazónica (ACCA), Missouri Botanical Garden Press, LimaGoogle Scholar
- Botero P (ed) (1999) Paisajes fisiográficos de la Orinoquía-Amazonía (ORAM) Colombia. Instituto Geográfico Agustín Codazzi, BogotáGoogle Scholar
- Correa SB (2003) Ichthyofauna of Lago Taraira, lower Rio Apaporis sytem, Colombian Amazon. Dahlia 6:59–68Google Scholar
- Erwin TL (1983) Beetles and other insects of tropical forest canopies at Manaus, Brazil, sampled by insecticidal fogging. In: Sutton SL, Whitmore TC, Chadwick AC (eds) Tropical rain forest: ecology and management, vol 2. British Ecological Society, Blackwell Scientific Publications, Oxford, pp 59–75Google Scholar
- Flores BM et al (2017) Floodplains as an Achilles’ heel of Amazonian forest resilience. Proceedings of the national academy of sciences. https://doi.org/10.1073/pnas.1617988114
- Fox J, Weisberg S (2011) An R companion to applied regression, 2nd edn. Sage, Thousand OaksGoogle Scholar
- Froese R, Pauly D (2017), version (06/2017) www.fishbase.org. Accessed 1 Oct 2017
- Furch K, Junk WJ (1997) The chemical composition, food value, and decomposition of herbaceous plants, leaves, and leaf litter of floodplain forests. In: Junk WJ (ed) The Central Amazon floodplain, ecology of a pulsing system, vol 126. Springer-Verlag. Berlin, Germany, pp 187–205CrossRefGoogle Scholar
- Goulding M, Carvalho ML, Ferreira EG (1988) Rio Negro, rich life in poor water. SPB Academic Publishing, The HagueGoogle Scholar
- Klinge H, Furch K (1991) Towards the classification of Amazonian floodplains and their forests by means of biogeochemical criteria of river water and forest biomass. Interciencia 16:196–201Google Scholar
- Martinez del Rio C, Wolf BO (2005) Mass-balance models for animal isotopic ecology. In: Starck MJ, Wang T (eds) Physiological and ecological adaptations to feeding in vertebrates. Science Pub Inc, Enfield, New Hampshire, pp 141–174Google Scholar
- Melack JM, Hess LL (2010) Remote sensing of the distribution and extent of wetlands in the Amazon Basin. In: Junk WJ, Piedade MTF, Wittmann F, Shongart J, Parolin P (eds) Amazonian floodplain forests: Ecophysiology, biodiversity and sustainable management. Springer, Dordrecht, pp 43–59CrossRefGoogle Scholar
- Parnell AC et al (2013) Bayesian stable isotope mixing models. Environmetrics 24:387–399Google Scholar
- PAT (1997) Zonificación ambiental para el plan modelo Colombo-Brasilero (Eje Apaporis-Tabatinga: PAT). Instituto Agustin Codazzi, IAC, BogotáGoogle Scholar
- Piedade MTF, Worbes M, Junk WJ (2001) Geological controls on elemental fluxes in communities of higher plants in Amazonian floodplains. In: McClain ME, Victoria RR, Richey JE (eds) The biogeochemistry of the Amazon Basin. Oxford University Press, New York, pp 209–234Google Scholar
- Stock BC, Semmens BX (2016b) MixSIAR GUI User Manual, Version 3.1. https://doi.org/10.5281/zenodo.56159