Genetic diversity may vary between landscapes that offer different environmental circumstances and living conditions.
Haugen has researched this by studying Triturus cristatus – the great crested newt. She has compared populations in a boreal forest landscape with nutrient-poor breeding ponds to those in an agricultural landscape with nutrient-rich breeding ponds.
The results showed an unexpected pattern.
"Newts in the forest had higher genetic diversity despite lower gene flow compared to newts in the agricultural landscape", says Hanne Haugen.
Model simulations indicated that this difference could be linked to the degree of variability in annual adult survival.
"High variability led to rapid loss of genetic diversity and larger dependence on gene flow. When adult survival was less variable, the populations were better able to maintain genetic diversity, even when gene flow was low."
These findings emphasize the importance of local habitats that buffer against harsh weather conditions that affect adult survival, thus genetic diversity.
"This will become even more relevant as global warming increases the frequency of extreme weather events", says Haugen.
Hanne Haugen has completed her PhD at the PhD programme in Applied Ecology and Biotechnology. Her thesis is titled "On buckets and sieves: disentangling the influence of landscape context on genetic dynamics in amphibian populations".
The main findings of the doctoral work:
- Genetic diversity was high in forest populations despite low gene flow.
- Genetic diversity was relatively low in agricultural populations despite high gene flow.
- High variability in annual adult survival had a strong effect on the populations' ability to maintain genetic diversity.
- High variability in adult survival led to genetic diversity eroding more rapidly, reducing the effectiveness of positive management measures, and led to a higher dependence on gene flow.
- Reducing the variability in annual adult survival can make populations more capable of maintaining genetic diversity even with low gene flow. This also makes them more responsive to positive management efforts, as genetic diversity is preserved and can accumulate over time.