MAE: Population dynamics

Within species, there is variation among populations, groups of animals in a particular area that interbreed. Population dynamics focusses on the study of demographics, such as growth and decline, and the environmental processes that driving them. Marine Animal Ecology contributes to the fields of population genetics and population ecology and studies how population dynamics change over time and space.


Genomic basis of bottlenecks

Overfishing and other pressures can lead to severe population bottlenecks. This may be the case for blacktip reef sharks, which are increasingly observed in the Maldives showing a rare skin disease. A current project will use genomic data to infer recent inbreeding history of the shark population. The aim is to develop a genomic tool to monitor inbreeding in wild populations.

Blacktip reef sharks. Wild types and disease types with skin disorder.
Blacktip reef sharks. Wild types and disease types with skin disorder.

Population dynamics on small islands

Seabirds are not doing so well. Especially on small islands such as those present in the Caribbean, threat of local extinction is high. A current study aims to answer what determines population success of Red-billed tropicbirds on St. Eustatius and Saba. Survival, migration patterns and population genetics will be studied and compared with patterns of large populations.

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Sea urchin populations in the Dutch Caribbean

In 1983, more than 95% of the sea urchin died due to an unknown disease around Saba and St. Eustatius in the Dutch Caribbean. This project aims to restore sea urchin populations as they are essential herbivores with important benefits for coral reef health. Both lab and field experiments will be used.

Juvenile sea urchin. Photo: A. Hylkema.
Juvenile sea urchin. Photo: A. Hylkema.

Population structure and migration of leatherback turtles

Not much is known about population structure of leatherback turtles in Indonesia. While there are known populations in Papua and Sumatra, not much is known about the Sumatran population. A soon to start project will focus on filling this gap by using mitochondrial and microsatellite DNA to infer population structure and by using satellite telemetry to infer movement patterns.

Population genetics and community assembly in marine lakes

Marine lakes can be considered island-like systems, since they are isolated, well-defined and have known ages. The populations residing within them have been variably isolated from the oceanic population and each other, depending on the extent of connection to the sea. Marine lakes can thus be used to use population genetics to study population differentiation and demographic history. Furthermore, classic Island Biogeography Theory hypotheses can be tested, such as the species-area and the species-isolation relationships. Finally, patterns of community assembly through processes of immigration, extinction, speciation and chance can also be studied in these discrete systems. Projects include:

Marine lake. Photo: C. de Leeuw
Marine lake. Photo: C. de Leeuw

Techniques used & Implications

To study population dynamics, Marine Animal Ecology performs field monitoring and performs molecular techniques. With a better understanding of population dynamics we are better able to conserve ecosystems to work towards climate resilience.