Research ArticleECOLOGY

Empty forest or empty rivers? A century of commercial hunting in Amazonia

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Science Advances  12 Oct 2016:
Vol. 2, no. 10, e1600936
DOI: 10.1126/sciadv.1600936
  • Fig. 1 Overview of the international trade in Amazonian animal hides through the 20th century.

    Modeled annual harvests for 20 species from the whole central-western Brazilian Amazon region (dark gray line), which include landings at Manaus and additional exports from other hinterland ports. 95% CIs obtained by bootstrap (gray area). Annual yields, converted to U.S. dollars indexed to 2015 prices, from extant hide export records from the central-western Brazilian Amazon (green dots and green trend line); these extant records represent a subset of the total modeled yield.

  • Fig. 2 Annual harvests and average prices for the main terrestrial and aquatic/semiaquatic species that were hunted commercially for hides and pelts in the central-western Brazilian Amazon, 1904–1969.

    Modeled total commercial harvests including those exported internationally [black lines ± 95% confidence interval (CI) regions in gray] and hide prices converted to U.S. dollars indexed to 2015 prices (green lines).

  • Fig. 3 Time series of animal harvests at nine localities in the central-western Brazilian Amazon.

    The curves show estimated number of hides transported per boat and are color-coded according to trade locality. Data are gleaned from cargo manifests of the J. G. Araujo Company.

  • Fig. 4 Harvest resilience displayed against habitat and demographic characteristics.

    Resilience of game populations to historical commercial hunting (represented by the percentage change in harvests across time) and correlation with habitat type (aquatic/terrestrial) (A) and intrinsic rate of natural population growth (Rmax) (B). Fitting a general linear model provides some evidence of higher population resilience in species with higher reproductive rates, but resilience is better predicted by habitat type (C). Akaike information criterion (AIC) weights (wAIC) for each model are given by exp(−ΔAIC/2) divided by the sum of this quantity over the four specified models.

  • Fig. 5 Two hypothetical hunting area scenarios displayed against terrestrial and aquatic habitats in the central-western Brazilian Amazon during the mid-20th century.

    Hunting catchment areas were obtained from 5- and 10-km buffer radii (red and yellow, respectively) around 3298 historical settlements in the 1950s and 1960s. These are predominantly nonindigenous settlements; locations of indigenous settlements in this period are mostly unknown. Low- and high-water seasons (dark and light blue, respectively) were reclassified from available raster imagery (48) for the focal area. Dashed lines delimit Brazilian state frontiers (state name in upper case). River names are in italic bold. See Materials and Methods for further details of the spatial analyses performed.

  • Table 1 Estimated numbers of animals hunted for their hides in the central-western Brazilian Amazon (1904–1969).

    Historical peak shows the year and estimated number of animals corresponding to maximum harvest for each species. Harvest change indicates the percentage change in modeled harvest for each species between a 5-year period centered on the overall pre-1965 peak harvest year for that species and the final 5-year period of exploitation from 1965 to 1969. The first peak occurred between 1937 and 1943 for every species except the capybara (1963). The final harvest for the manatee comprises meat production instead of hides and is taken from 1969 to 1973; see text for details. 95% bootstrapped CIs are shown in parentheses.

    SpeciesTotal (1904–1969)Historical peakYearHarvest change
    Terrestrial
    Collared peccary (Pecari tajacu)5,443,795 (4,740,807–6,177,067)363,425 (238,190–500,988)196915 (−22, 68)
    Red brocket deer (Mazama americana)4,152,218 (3,685,451–4,570,403)169,885 (109,431–249,834)196916 (−16, 71)
    White-lipped peccary (Tayassu pecari)3,110,753 (2,598,553–3,626,290)273,408 (212,667–356,238)1939−67 (−78, −51)*
    Ocelot/margay (Leopardus pardalis/Leopardus wiedii)804,080 (529,517–1,223,279)44,448 (6,690–115,648)1969−13 (−66, 145)
    Jaguar (Panthera onca)182,564 (112,533–313,385)9,344 (2,807–20,318)1938−30 (−88, 249)
    Aquatic/semiaquatic
    Black caiman (Melanosuchus niger)4,415,469 (3,978,153–4,846,254)313,907 (249,474–390,660)1943−92 (−95, −87)*
    Capybara (Hydrochoerus hydrochaeris)1,040,533 (896,826–1,223,881)86,687 (61,431–115,778)1963−75 (−84, −61)*
    Giant otter (Pteronura brasiliensis)386,491 (265,399–581,032)35,589 (18,175–58,149)1937−88 (−96, −64)*
    Neotropical otter (Lontra longicaudis)362,335 (203,411–636,137)14,919 (3,655–32,961)1937−20 (−82, 359)
    Manatee (Trichechus inunguis)113,033 (92,658–138,583)15,872 (12,558–19,820)1938−91 (−94, −88)*

    *Percentage harvest change is significantly different from zero at the 5% level.

    Supplementary Materials

    • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/2/10/e1600936/DC1

      text S1. Historical documents list.

      text S2. Comparing the impacts of contemporary subsistence hunting versus historical commercial hunting in Amazonia.

      text S3. International demand for Amazonian hides through time.

      fig. S1. Rural population in the central-western Brazilian Amazon.

      fig. S2. Central-western Brazilian Amazon yields (U.S. dollars in 2015 currency equivalence) for foremost 20th century products.

      table S1. Average hide weights of commercially hunted species.

      table S2. Intrinsic rate of natural increase (Rmax) for game species and parameters required for its calculation by the Cole equation.

      table S3. Area of terrestrial and aquatic habitats, and their accessibility by hunters, under two hunting catchment area scenarios (buffers of 5 and 10 km around all settlements) in the central-western Brazilian Amazon.

      table S4. Comparison between the Robinson-Redford production index and commercial harvests at two historical peaks for terrestrial species.

      table S5. Comparison of the minimum refuge area required for maximum sustainable harvests (AMSY) according to the Joshi and Gadgil model (α = 1/λ) to actual refuge area (Arefuge) in the central-western Brazilian Amazon.

      References (139148)

    • Supplementary Materials

      This PDF file includes:

      • text S1. Historical documents list.
      • text S2. Comparing the impacts of contemporary subsistence hunting versus historical commercial hunting in Amazonia.
      • text S3. International demand for Amazonian hides through time.
      • fig. S1. Rural population in the central-western Brazilian Amazon.
      • fig. S2. Central-western Brazilian Amazon yields (U.S. dollars in 2015 currency equivalence) for foremost 20th century products.
      • table S1. Average hide weights of commercially hunted species.
      • table S2. Intrinsic rate of natural increase (Rmax) for game species and parameters required for its calculation by the Cole equation.
      • table S3. Area of terrestrial and aquatic habitats, and their accessibility by hunters, under two hunting catchment area scenarios (buffers of 5 and 10 km around all settlements) in the central-western Brazilian Amazon.
      • table S4. Comparison between the Robinson-Redford production index and commercial harvests at two historical peaks for terrestrial species.
      • table S5. Comparison of the minimum refuge area required for maximum sustainable harvests (AMSY) according to the Joshi and Gadgil model (α = 1/λ) to actual refuge area (Arefuge) in the central-western Brazilian Amazon.
      • References (139148)

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