Understanding demographic and genetic change in an expanding population through simulation modelling
Understanding the interplay between demographic changes and genetics changes is difficult as these two sources of change are interconnected and undergo complex feedback loops. Based on data from a 22+ year study of the spotted hyena (Crocuta crocuta) in the Ngorongoro Crater, Tanzania, we tailored an individual based simulation model to study a wide range of both fundamental questions and questions that have practical implications in terms of conservation.
Simulation modelling of wild animal populations is a useful tool to study complex ecological and genetic questions that can be difficult to answer using more traditional approaches. Based on data from a 24 year study of the spotted hyena (Crocuta crocuta) in the Ngorongoro Crater, Tanzania we have built an individual (agent) based model that incorporates social, demographic, and genetic information to create a robust simulation of this large carnivore. Spotted hyenas are a particularly interesting species to study as they exhibit nepotism in their strict social hierarchy, a behaviour that is more commonly observed in primates such as baboons and humans. We are using our demo-genetic model to study this nepotistic behaviour and understand how it may mediate the impacts of environmental change and conservation management strategies. This work will help us better understand an important savannah species and, more broadly, provide insights into the consequences of nepotism in animal societies.
Current research questions:
How is spotted hyena society affected by demographic change?
We characterise the structure of the spotted hyena social system by measuring the level of inequality in reproductive success using metrics such as the Gini coefficient and binomial skew index. We will use our simulation model to identify those demographic variables (e.g., sex ratio, lifespan) that most strongly affect the level of inequality in the spotted hyena social system.
How will spotted hyenas be affected by future environmental change?
We will use our simulation model to predict the effects of different conservation management strategies (e.g. livestock grazing, culling) and future environmental change scenarios (e.g. climate change) on both the level of inequality and population viability of the spotted hyena. In our demo-genetic model we can vary the strength of nepotism in the spotted hyena social system. We will use this functionality to test how differing levels of nepotism may mediate the impacts of such environmental change.
How does nepotism affect genetic diversity and evolutionary potential?
We will use the genetic component of our demo-genetic model to quantify expected genetic diversity (simulationg neutral genetic elements) and evolutionary potential (simulating locus under selection). As with our study of environmental change, we will vary the strength of nepotism in our simulations and quanitfy how this may mediate our measures of genetic diversity and evolutionary potential.