Why is biodiversity under threat?
Florian: There are many factors. The destruction of habitats due to intense land use practices, such as agriculture or urbanisation and non-sustainable use of natural resources, are among the major threats to biodiversity. Also pollution, especially chemical pollution, is negatively affecting biodiversity. Further negative effects on biodiversity are caused by direct exploitation of organisms, such as overfishing, by non-native species and climate change.
Catherine: Most factors that impact biodiversity, in general, are well known. However, we don’t know exactly which species are going to be affected or the implications this will have on other species. Links between species are important, but it’s hard to predict exact outcomes because nature is complicated. That’s an additional reason beyond what Florian mentioned as to why it is difficult to maintain biodiversity.
What about biodiversity in Switzerland?
Florian: The situation is comparable to global trends: the intensification of land use by agriculture, urbanisation and expansion of infrastructure such as for transportation have strongly altered natural ecosystems and contributed to the loss of biodiversity, especially since the 1950s. In the medium term, climate change will become more significant due to our mountainous topography. Organisms adapted to colder climates will have to shift their habitat range to higher elevations, but may eventually run out of suitable habitats.
Catherine, you lead the new research initiative Blue-Green Biodiversity together with Florian. What does “blue-green” mean?
Catherine: The point of blue-green is to study both aquatic and terrestrial systems simultaneously. So far, scientists tend to focus on a specific ecosystem. But the systems are interconnected. For example, many insects have a life stage in water, before they emerge to a life stage on land. Insects that emerge from the water are very nutritious to birds, because they are rich in fatty acids. These connections are not usually studied. It is also important so study more than one system to learn about fundamental principles. One of these would be resilience. If we disturb an ecosystem, how long is it before the ecosystem returns to its previous state? If experts from both sides simultaneously study the same principle in both terrestrial and aquatic systems with a similar approach, we can begin to understand the underlying mechanisms in a more cohesive way.
Florian: I agree with Catherine. A focus on aquatic or terrestrial habitats only, as was often the case in the past, isn’t able to capture the whole system. We need to study biodiversity in a more holistic way or we will miss important dependencies and cascading effects. For example, agricultural practices can have very strong effects on the water quality and aquatic biodiversity. Consequently, terrestrial and aquatic ecologists need to team up to study the dynamics across ecosystems.