IUCN / SSC Cat Specialist Group - Digital Cat Library |
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| Wolff, F. | |
| Vertebrate ecology in caatinga: A. Distribution of wildlife in relation to water. B. Diet of pumas (_Puma concolor_) and relative abundance of felids | |
| 2001 Full Book | |
Caatinga is a seasonally dry forest in northeastern Brazil. Despite the strong seasonality of rainfall, the fauna of caatinga is characteristic of mesic biomes and shows no special physiological adaptations for coping with water limitation. Overall, the fauna of caatinga is poor in endemics and species richness is lower than in other systems. This study has two major objectives. First, I describe the seasonal distribution of common medium- and large-sized vertebrates in relation to water sources. Second, I analyze the feeding ecology of a large, widespread predator in caatinga. This study was conducted from October 1999 until August 2000 in Serra da Capivara National Park. The first part of this study describes the seasonal distribution of tegu lizards (_Tupinambis teguixin_), rusty-margined guans (_Penelope superciliaris_), seriemas (_Cariama cristata_), crab-eating foxes (_Cerdocyon thous_), pumas (_Puma concolor_), gray brocket deer (_Mazama gouazoubira_), white-collared peccaries (_Tayassu tajacu_) and agoutis (_Dasyprocta prymnolopha_) based on observational data. During the dry season, foxes and seriemas moved from the dry plateau of the park to valleys where water holes are present. Other species showed seasonal site fidelity and were observed mostly at lower (deer) or higher (agouti) elevations. With the exception of pumas and agoutis, all species showed close association with available water sources, at least during the dry season. The year-round availability of water at lower elevations and overall differences in vegetation along the elevational gradient influenced the distribution of species are discussed. The second part of this study analyzes the diet of pumas in relation to the relative abundance and biomass of prey. The relative abundance of felids in caatinga is compared with other neotropical systems. Relative abundance of prey and felids were estimated using remote cameras. Puma diets were described following analysis of scats. Nine-banded armadillos (_Dasypus novemcinctus_) accounted for 70 % of prey items and 69 % of the biomass consumed. Pumas preyed on armadillos and lesser anteaters (_Tamandua tetradactyla_) more than expected based on their relative abundance. Pumas selected against large prey, such as peccaries and deer, and took agoutis and skunks (_Conepatus semistriatus_) in proportion to their relative abundance and biomass. Pumas do not act as energy maximizers, but rather as number maximizers, taking prey on encounter. Habitat structure is suggested as an explanation for the observed prey selectivity, although competition with jaguars and differences in prey vulnerability could also play a role. Pumas and oncillas (_Leopardus tigrina_) are more abundant than jaguars (_Panthera onca_) and ocelots (_L. pardalis_) in this system. Greater abundance of pumas than jaguars is explained by the scarcity of large prey in this system, which favors the smaller puma. Low abundance of ocelots could be due to low density of small mammals in caatinga and competition with pumas for medium-sized prey. |
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