Socially Driven Health Dynamics

Models of health histories are essential tools to quantify differential health and longevity in subgroups defined by gender, race or ethnicity, and socio-economic status. A current problem for understanding health and aging is that socially disadvantaged subgroups experience different baseline measures of health and increased mortality yet are often described with similar model parameters as advantaged groups. Through comparative studies using the Cayo Santiago rhesus macaque population, our research integrates demography, sociality, and health to study individual health histories and formulate demographic models for accurate assessment of socially driven health history dynamics across subgroups.

Stochastic Processes on Demography

​As natural selection acts on individual variability, it is imperative to understand how this variability is generated and maintained. The variation we typically consider from sources such as the environment, genetics, and their interactions is quite small compared to the vast unexplained variability observed in traits. This is important because if adaptive, this variability accelerates evolutionary change, but if neutral, it slows the pace of evolutionary change with direct implications to management and conservation. Our research aims to understand and quantify stochastic variability – as opposed to fixed (genetic) variability – and measure the resulting population dynamics.

Extreme Events as Drivers of Individual Variability

Random fluctuations in the environment can affect the performance of individuals with significant consequences in population dynamics. Following extreme events, individuals might be forced to explore new niches by diversifying life histories, rather than being driven to an optimal one. Our research addresses the relationship between extreme events and the generation of individual variability. Recently, the Cayo Santiago rhesus macaque population suffered a direct hit from a major hurricane, bringing the unprecedented opportunity to study whether stochastic extreme events generate variability in individual life histories.

Demography Across Spatial Scales

Animal populations with complex phenology present significant challenges for accurate modeling due to lack of adequate data. If the study area is not well defined or there is heterogeneity in individual movement, inferences on density and consequent population dynamics are less robust. Given these significant challenges, we are part of the Salamander Population and Adaptation Research Collaboration Network which uses spatial capture mark-recapture models, a framework that jointly fits a spatial model of abundance and detection to the encounter history data of individuals. These models allow for biologically meaningful estimates of abundance and space use in populations with uncertainty.

Field Site - Cayo Santiago, Puerto Rico

rhesus macaques at Cayo Santiago

This island off the east coast of Puerto Rico is home to over 1500 free-ranging rhesus macaques and is administrated by the Caribbean Primate Research Center of the University of Puerto Rico-Medical Sciences Campus.