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It is cold and muddy in De Driehoek, a small nature area within the Utrecht Science Park (USP). Jonas Lembrechts, a researcher in the Ecology and Biodiversity group, and two of his students have just finished mapping the plant species growing in several small plots in the area. By repeating this process regularly, over many years and in numerous locations across the Netherlands, they aim to build a clear picture of how biodiversity is changing, and how factors like nitrogen pollution and climate change are influencing it. Lembrechts: “Measuring biodiversity in the middle of winter might not seem like the obvious choice, but this way we also capture seasonal variations.”

The project in the Netherlands is still in its early stages and currently focuses on a limited number of areas, including the Utrecht Science Park (USP). However, the goal is to set up similar monitoring efforts across the entire country. Elsewhere in Europe, the project known as has now been running for about four years. Lembrechts has clear plans for the Netherlands. “We want to include all the country’s typical habitat types, such as heathlands, dune areas, and forests,” he explains. “But we are also interested in unexpected places, like here on campus or a city sidewalk.”

We keep collecting data, even if a green space is turned into a parking lot.

Mushrooms and small plots

Although grand in scope, the study’s design is relatively simple. Each site is monitored in exactly the same way. Researchers begin by marking a spot by sticking a rod in the ground, next to which they place a sensor which more or less resembles a mushroom. This sensor measures soil temperature and moisture levels, helping to track how weather conditions affect the environment. Next, the researchers document which plant species are growing within a one-square-meter area around the rod. At the Utrecht Science Park, these plots are revisited every three months, while locations elsewhere in the Netherlands are surveyed annually.  Lembrechts: “We keep collecting data, even if a green space is turned into a parking lot.”

What strategies work best to protect biodiversity?

On both a small and large scale.

Careful thought has been given to the spatial distribution of the plots. The closest ones are set 11 meters apart, with distances gradually increasing—first to 33 meters, then 100, 300, and finally 900 meters. Lembrechts: “This approach helps us understand not only the impact of factors like nitrogen pollution and climate change on biodiversity, but also the scale at which management is most effective. What strategies work best to protect biodiversity?”

The plan is to continue monitoring for years. Lembrechts: “By measuring continuously over the long term, we can get a clear picture of biodiversity variation. Right now, when studying long-term changes in biodiversity, people typically compare two points that are years apart. But if in one year it is relatively dry in the spring, and the other it is wet, it is hard to know what you are really comparing.”

Not a contest

But when is biodiversity truly thriving? Lembrechts emphasizes that it is not a contest about having the most species. Lembrechts: “It is about plant communities that function well. Take heathlands, for example. You will not find the highest number of plant species there. But the species that are present are often unique to that habitat.”