The PhD Interview: Pollen from the past may predict the future
Vivian Astrup Felde studies the relationship between pollen and plants. She looks for changes in vegetation in Norway. Her research could provide answers to what to expect of the future climate.
In your dissertation you study biodiversity over time. What is biodiversity?
“Biological diversity, or biodiversity, encompasses all different types of life forms that exist on Earth. So it depends on what scale you want to examine. I am a biologist and study plants and am concerned about plant diversity or vegetation in different ecosystems. There are many methods for estimating biodiversity. Generally, this is considered a simple measurement for how functional one ecosystem is compared to others.”
Why is it important to study the biodiversity of the past?
“The vegetation that we see today is a part of history, something that has changed over time. There are interesting historical reasons to study this, and I believe that in order to get to know how things have changed in the past, it can help us understand what may happen in the future.”
In what way?
“For instance, we can study how and why the vegetation has changed from the last Ice Age to the present day. There are many different drivers of vegetation change to consider, such as changes in climate and the influence of human beings, which make the scenery change.”
In your project you have studied pollen. How come?
“Pollen is an excellent analysis object when you want to find out how the vegetation has changed through time. By analysing pollen, you can determine what plant species the various pollen grains originate from. The problem is that plants produce different amounts of pollen and spread differently.”
Why is this problematic?
“Some pollen types are easily transferred by the wind, while others are transferred via insects. Often we see that the plants with a high pollen production and are carried by wind dominate the pollen samples, whereas we can find little or nothing of the plants that produce small amounts of pollen or that are transferred by insects. Pollen with long distance dispersal can also be present in pollen samples when the plant is not in the area where the sample is collected. At the same time we cannot identify all pollen types to species, but we have to manage with genus or family. This gives us a somewhat skewed relationship between the number of plants in the vegetation and the number of pollen types in the pollen sample.”
How do you approach the pollen and vegetation sampling?
“I mapped the vegetation around 52 lakes in the Setesdal area from Haukeli to Kristiansand, where pollen samples were already available. Pollen samples had been collected from the top sediments in these lakes as that represents the current conditions. I spent two summers doing vegetation sampling and writing down each plant species I found and their expansion. After this job was done, I tried to find a correlation between the composition and the amount of pollen and plants by reducing biases in the pollen samples and using different statistical methods.”
What do you think is the most important aspect of your research?
“To attempt to find a method that can be used to improve the past diversity estimates and to get a complete picture of how the richness and diversity of plants has changed over time. Still, it is very difficult to get a complete picture of this. There are so many sources of error. I do not believe it is possible to determine exactly how many species that have been in a particular area previously. But it is important to ensure that the proportions are correct when you are comparing different vegetation types.”
What are you working on now, and what is your future career dream?
“I am working on a temporary project until December. I am analysing a data material from Columbia which is 1.2 million years old. The long-term hope is to get a postdoctoral fellowship. I really want to carry on with my research!”