Documenting the impact of hunting in the Amazon

14 October 2016

Close-up portrait image of Associate Professor Rachel Fewster.
Associate Professor Rachel Fewster

Just how much damage did hunting for hides do to wild animal populations in the Brazilian Amazon in the 20th century? Department of Statistics conservation expert Rachel Fewster is one of a team that has used previously unpublished shipping records about wild animal hide exports from the region to estimate how hunting affected animal population survival rates.

The team’s research has just been published in the open-access journal Science Advances, and concludes that water-dwellers like giant river otters, black caiman and manatees suffered population collapse and local extinction. In contrast, land animals including collared peccaries, deer and even jaguars lived in areas less accessible to hunters. This helped their populations remain resilient, even when the international fashion trade was demanding hides in the 1930s and 1940s and again in the 1960s.

The study’s lead author was André Antunes of the Wildlife Conservation Society in Brazil, working alongside Associate Professor Fewster; Eduardo Venticinque (Federal University of Rio Grande do Norte); Carlos Peres (University of East Anglia); Taal Levi (Oregon State University); Fabio Rohe (INPA), and Glenn Shepard (Goeldi Museum, Brazil).

Associate Professor Fewster says that by modelling overall harvest trends, the study estimated that between 1904 and 1969, at least 23 million animals representing 20 species of mammals and reptiles were hunted for hide exports in the Western Brazilian Amazon – an area about eight times the size of New Zealand. The species hunted most heavily were those with valuable pelts for luxury furs, including giant river otters and spotted cats such as jaguar, ocelot and margay, as well as species valuable for their leather such as the black caiman, which supplied prized crocodile skins, ungulates including deer and the pig-like peccaries, the enormous guinea pig-like capybara and the manatee, a large aquatic mammal.

The team took advantage of a “veritable gold mine” of unanalysed historical documents and unpublished shipping records about the quantity and scale of the trade. However, Associate Professor Fewster says that these figures represent only hides that were formally registered on ship manifests and port landing records.

“These records would underestimate the total impact of hunting on wild animal populations, since many animals are fatally wounded in the course of hunting, many skins rot and are discarded on their way to market, and a portion of the harvest was probably undeclared to avoid taxes.”

But the research is of more than historical interest. Its insights will inform conservation planning for the Brazilian Amazon, whose animal refuges are threatened by deforestation, roads, logging, large infrastructure projects and agriculture.

Commercial animal hunting became a cornerstone of the Amazonian economy after the collapse of the Amazonian rubber trade in 1912, when plantation rubber from Malaysia made wild Brazilian rubber commercially unviable. When Malaysian plantations were captured by the Japanese in World War II, the United States made massive investments in Amazonian rubber, leading to a large surge in the human population and, consequently, in hunting activity.

The 1960s saw a second peak as the clothing and fashion industry demanded exotic furs. Even though hunting was officially banned in Brazil in 1967, loopholes permitting the sale of warehoused hides meant that illegal hunting and hide exports continued until the ratification of the Convention on the International Trade in Endangered Species (CITES), to which New Zealand is a signatory, in 1975.

Demand for exotic furs continued through the 1980s, and it was only with the 1992 Rio Earth Summit that international opinion finally turned against the use of wild animal furs as fashion accessories.