MADISON At first glance, the northern muriqui monkey is a prime conservation success story.
These Brazilian primates are critically endangered, but in the past 30 years a population on a private reserve has grown from just 60 individuals to some 300, now comprising almost a third of the total remaining animals.
As the population grows, though, it is offering researchers a glimpse into a new phase of recovery as it begins to face the limitations of its habitat. A recent analysis of the factors contributing to this population's tremendous growth reveals surprising trends that raise new questions about conservation, recovery and what constitutes a healthy population.
University of WisconsinMadison anthropologist Karen Strier has led observational field studies of this muriqui population for 30 years, meticulously charting demographics and life history of hundreds of individual monkeys. An analysis, published Sept. 17 in the journal PLOS ONE with UWMadison mathematical ecologist Anthony Ives, provides the most comprehensive, quantitative look to date at long-term demographic trends and the role of individual features such as fertility, mortality, and sex ratios.
The researchers used statistical models designed to handle multiple levels of data so they could construct a comprehensive view of the population while still accounting for variation among individual animals. The approach allowed them to identify specific demographic trends and their effects on the overall population size.
"By separating out these components we were able to see the patterns in the data," Strier says, many of which were unexpected. For example, the analyses revealed increases in both fertility and mortality a surprising combination, especially in a population that is still growing. In addition, they documented a remarkable and unexplained shift in infant
|Contact: Karen Strier|
University of Wisconsin-Madison