Harmsen B.J.,Panthera Foundation |
Harmsen B.J.,University of Southampton |
Foster R.J.,University of Southampton |
Silver S.,Wildlife Conservation Society |
And 2 more authors.
Relative abundance indices are often used to compare species abundance between sites. The indices assume that species have similar detection probabilities, or that differences between detection probabilities are known and can be corrected for. Indices often consist of encounter frequencies of footprints, burrows, markings or photo captures along trails or transect lines, but the assumption of equal detection probabilities is rarely validated. This study analyzes detection probabilities of a range of Neotropical mammals on trails in dense secondary forests, using camera-trap and track data. Photo captures of the two large cats, jaguars (Panthera onca) and pumas (Puma concolor), were correlated solely with trail variables, while photo captures of their potential prey species had no correlation or negative correlation with trail variables. The Neotropical mammals varied greatly in their tendency to follow or cross trails based on footprints surveys. This indicates that camera locations on trails will have varying detection probability for these Neotropical mammals. Even the two similar-sized jaguars and pumas, occupying relatively similar niches, differed subtly in their use of trails. Pumas followed trails more completely while jaguars were more likely to deviate from trails. The ecological significance of these findings is that jaguars seem to be more willing to use the forest matrix away from trails than do pumas. We conclude that trail-based indices, such as photographic captures or tracks along trails, are not appropriate for comparison between Neotropical species, and not even between relatively similar species like jaguars and pumas. © 2009 by The Association for Tropical Biology and Conservation. Source
Braczkowski A.R.,University of Oxford |
Balme G.A.,Panthera Foundation |
Balme G.A.,University of Cape Town |
Dickman A.,University of Oxford |
And 6 more authors.
In a number of African countries, the trophy hunting of large felids is an important revenue generator for landholders, governments and in some cases communities. The hunting of large felids is especially profitable but they are sensitive to harvest, as the killing of prime-aged, dominant males can lead to infanticide and lowered reproductive success. In an attempt to limit the negative impacts of trophy hunting on large felids, the scientific community has proposed a number of interventions, including age restrictions on the animals that may be hunted. Such interventions are theoretically complementary to trophy hunting, as hunters typically seek large trophies, and older animals are normally larger than younger ones in large felids. If trophy size results in an increase in trophy price, then interventions that improve average trophy size could confer elevated earnings. This is particularly true if such interventions increased the number of failed hunts such that the same tag can be sold more than once. However, if trophy size is not one of the most important factors determining the desirability of a hunt (which we judge by the price paid for a trophy hunt package), it may be more difficult to implement such schemes. It is therefore important to evaluate potential determinants of trophy hunt package price; and we examine that here for leopards (Panthera pardus) in Africa, at both the country and outfitter level. We show that Tanzania and Botswana have the most expensive package prices while South Africa has the cheapest packages. At the country level, we found no statistical relationships between package price and leopard trophy size (either through advertised website or Safari Club International (SCI) leopard trophy size), country GDP, relative hunt success, or quota size. Contrastingly, the number of charismatic species offered within a package and an index of outfitter reputation (as measured by total SCI trophy records) were positively associated with package price. Interestingly, SCI leopard trophy size was inversely correlated with package price. Our results suggest that hunters do not value leopard trophy size above other factors, which could hinder the implementation of more sustainable, age-based leopard hunting regulations. Source