Filtering by
- All Subjects: Interannual variability
- Creators: Hall, Sharon
Jaguar population decline is largely attributed to habitat loss and retaliatory hunting. Maintaining a viable prey base in the wild can help to mitigate this issue and decrease human-wildlife conflicts. This study aims to assess the presence of prey species in jaguar habitat in order to inform conservation efforts to maintain and improve the health and relative abundance of the wildlife community. We analyzed nearly 40,000 photographs from 85 camera traps to assess the presence of prey species at sites where jaguars are known to occur. Jaguar-prey site overlap was calculated based on the percent of jaguar sites where each prey species was present. Medium-sized mammal prey species (e.g. Central American agouti) were present across the majority (up to 87%) of sites, while large mammal prey species were present in 16%-42% of sites, varying by species. These results suggest that conservation management of jaguars would benefit from improved monitoring and maintenance of a stable prey community.
Further, I investigated the effect of precipitation variation on functional diversity on the same experiment and found a positive response of diversity to increased interannual precipitation variance. Functional evenness showed a similar response resulting from large changes in plant-functional type relative abundance including decreased grass and increased shrub cover while functional richness showed non-significant response. Increased functional diversity ameliorated the direct negative effects of precipitation variation on ecosystem ANPP but did not control ecosystem stability where indirect effects through the dominant plant-functional type determined ecosystem stability.
Analyses of 80 long-term data sets, where I aggregated annual productivity and precipitation data into five-year temporal windows, showed that precipitation variance had a significant effect on aboveground net primary production that is modulated by mean precipitation. Productivity increased with precipitation variation at sites where mean annual precipitation is less than 339 mm but decreased at sites where precipitation is higher than 339 mm. Mechanisms proposed to explain patterns include: differential ANPP response to precipitation among sites, contrasting legacy effects and soil water distribution.
Finally, increased precipitation variance may impact global grasslands affecting plant-functional types in different ways that may lead to state changes, increased erosion and decreased stability that can in turn limit the services provided by these valuable ecosystems.