Hunting-Related Changes in Game Encounter Rates from 1994 to 2001 in the Mbaracayu Reserve, Paraguay

This longitudinal study examines the impact of native hunting on the populations of 10 important game species in the Mbaracayu Reserve, Paraguay. From July 1994 to July 2001, native Ache research assistants surveyed 7,535 km of diurnal random transects in the reserve. Analyses of data from these transects and harvest- rate data from 5,526 Ache hunter days suggest that the hunting return rate declined significantly for one species. Nonsignificant declines were observed for 6 of the other 9 species. Native harvest percentages of the stock population appear sustainable for 10 major prey species, but rates of harvest from nonindigenous poaching could not be determined. Crude encounter rates for all 10 species declined over time, but only 2 of these were statistically significant in a univariate model. Multivariate logistic regression controlling for habitat type and location in the reserve showed significant declines in encounter rates over time for 4 species, but the effect of interaction between time and hunting pressure failed to confirm that declines in encounter rates were steeper in more-hunted versus less-hunted areas of the reserve. This may mean that other factors unrelated to hunting pressure are responsible for some of the declines in game encounter rates.