COLLEGE STATION – A paper published in the Journal of Applied Ecology by two Texas A&M University scientists warns of impacts to fisheries and fish diversity, stemming from continued deforestation of the Amazon River.
The paper, “Relationships between forest cover and fish diversity in the Amazon River floodplain,” can be read in its entirety here: http://onlinelibrary.wiley.com/doi/10.1111/1365-2664.12967/abstract. Dr. Kirk Winemiller, Texas A&M AgriLife Research fisheries scientist and Regents Professor in the department of wildlife and fisheries sciences at College Station, and Caroline Arantes, Winemiller’s doctoral student, were the authors.
“The paper reports our findings on relationships between forest cover and fish diversity in the Amazon River floodplains,” Winemiller said.
Arantes reported the Amazon, like most major tropical forest areas of the world, is being systematically cleared for agriculture, human habitation and hydropower development. While viewed as progress by some, permanent species diversity damage could well be the outcome.
“Floodplain forests are key habitats and food producing areas for fish,” she said. “In a pristine forested state, fish thrive on food resources that fall into the water, and survival of many fishes is enhanced by the complex habitats of flooded zones. Deforestation upsets this natural balance developed over time not only to the detriment of the fish population but also to the millions of people relying on many of these species for food.”
Arantes and Winemiller conducted a number of field expeditions to the Lower Amazon River to find how deforestation affects fish diversity. Some species, they noted, may be more sensitive to change than others. Their work centered on fish community structure at sites ranging from densely forested to mostly devoid of tree growth.
“We found fish diversity was directly associated with the amount of forest cover and various environmental factors,” Winemiller said. “Some fish with similar life history, feeding and microhabitat needs are positively associated with forest cover, while others were most common in areas of open water or containing beds of herbaceous vegetation, representative of the deforested areas.”
Arantes reported forested areas supported populations of fish species with diverse ecological strategies, and species with broad ecological tolerance tended to be most abundant in deforested areas. Unfortunately, these generalists tended to have low importance in local fisheries, and most of the high-value species tended to be associated with forested areas.
“The forest provides fruit, seeds, microorganisms and other food resources that are important in aquatic food webs of the Amazon River floodplains. To flourish, some fish species may even require resources originating from the forest, so when the forest is removed, these species decline or disappear,” she said.
“In Brazil there are protected areas, but these were designed to conserve terrestrial species,” she said. “Very few areas have been reserved to protect fish stocks in the Lower Amazon River, and none are located within our study area.
“Our findings, together with those from several other recent studies, illustrate the benefits of forest cover in the Amazon for conservation of the region’s rich fish diversity that is so important for regional food security.”