Camille Allonsius, project leader of ‘CurieuzeNeuzen in de Tuin’ and Stijn Van de Vondel, PhD, both connected to the UAntwerpen, are enthusiastic. They are about to announce their first analyses of the soil measurement results of about 4.400 citizen scientists and they are launching a follow-up project in March 2022, again with some 3.000 measurement points in various ecosystems. The main goal is the delivery of an internationally unique dataset that will provide us insight into the climate resilience of our gardens, parks, natural and agricultural areas.  

Network of 'lawn daggers'

At the start of your project, in January 2021, no less than 50.000 'CurieuzeNeuzen' signed up to measure heat and drought in their gardens. An unexpected success?

Camille Allonsius: ‘That's right, the call was open for barely three weeks, when the counter clocked in at 50.000 potential participants. The problem of drought and heat in our Flemish gardens is of major concern among citizens. To us it was a double-edged sword; on the one hand it is fantastic that an extensive network of citizens is coming forward, on the other hand we also had to cancel a lot of enthusiasts. For this reason, in consultation with our partners, we immediately deployed the social media. The measurements are shared online via a dashboard, a dot map and an extensive journalistic file with interim findings. Those who were unable to participate were and are still able to see the measurements and results. The participants themselves will receive a personal garden report afterwards.’

How is the data collection organised? 

Camille Allonsius: 'Each participant takes a soil sample from his or her garden and sends it to UAntwerpen, where we determine the soil type (% clay, sand and loam) and the carbon content in the lab. Participants also receive a soil sensor, which we call a ‘lawn dagger’. This ‘lawn dagger’ measures temperature every 15 minutes at three points, above the soil, on the soil and in the soil. The dagger also records the moisture content of the soil itself. All the sensors are connected to the Internet of Things, they connect to a transmitter mast every day and send the data via a network from Orange. This way the data ends up directly in the CurieuzeNeuzen database and every citizen gets a daily update of the measurement data in a personal dashboard. Importing the data afterwards, after the project, is not necessary anymore and that is really innovative.’

Air conditioning, sponge and archive

What scientific results or insights do you hope to achieve?  

Stijn Van de Vondel: ‘Drought and heat are complex problems. With the microclimate network we are setting up, we want to identify the patterns that cause drought and heat. Our new scientific insights can be used to generate computer models for heat stress and possibly to predict heat waves. Moreover, the data give us insight into how a garden works and an insight into greenery as a cooling element. How does nature cool near or in a city? In other words, we are looking at the garden as air conditioning but also at the garden as a sponge and even as a carbon archive. Last summer, for example, thanks to the measurements of our ‘lawn daggers’ in more than 4.000 soils, we were able to record how well Flemish gardens are able to capture rainwater. Our data will also be included in the international SoilTemp database. This database mainly contains data from natural areas, to which we add substantial data from gardens. Because of the 4.400 measurement locations in the CurieuzeNeuzen project, the amount of data in the SoilTemp database will be doubled immediately.’

Climate Adaptation

The weather extremes are increasing. Sometimes it rains very hard locally, causing flooding. At the same time, we often experience long dry periods in the summer. How can we make Flanders more climate proof?  

Camille Allonsius: ‘Climate-proof gardens help prevent flooding and can withstand drought for longer periods. If you know that private gardens in Flanders take up about 12% of the total surface area, even 18% if you include the broader managed green spaces, then you know that greenery can play an important role in climate adaptation and can, for example, help keep water out of the streets. Of course there are factors that you cannot influence such as the location of a garden or the altitude, but the potential, through relatively minor interventions, to ensure a better climate adaptation is great. For example, planting is important; trees play a big role, but also the management of the greenery, such as the length of the grass and the boundaries of the plots. Long grass, for example, is more drought-resistant than a milled lawn.'
Stijn Van de Vondel: 'We see that many cities and municipalities share and pick up on this concern. Local governments can play an important role; some appoint garden coaches or pavement coaches. What we do know for sure now is that we can cool our towns and cities smartly with more blue and green. Trees and vegetation provide shade, open water and greenery provide cooling through evaporation. By avoiding paving and installing blue-green elements, we buffer rainwater and cool the urban environment. What factors have a major impact on drought in our gardens? What explains the differences in drought sensitivity? How can my lawn better survive drought? Can you use smart garden management to reduce the impact of a summer drought? These are all legitimate questions that our project seeks to answer.'

A naughty wish

What learning path did you take as a citizen science project during a pandemic?

Stijn Van de Vondel: ‘CurieuzeNeuzen in de Tuin’ is a roller-coaster project. Getting the sensors online, for example, was not easy. The Czech team responsible for the production and delivery of the sensors could not get on site to test them because of the pandemic. So the launch was the test. Meanwhile, the realization of the connection between participants and their data is going extremely well.’ 
Camille Allonsius:  ‘Also, in terms of logistics and communication, it was all hands on deck. Collection points had to be closed and we had to find a balance between accessible communication and scientific correctness. Having three people on standby for an entire weekend was no exception.’ 

A sequel to 'CurieuzeNeuzen in de Tuin' is now in the pipeline, to obtain an even more complete data set? 

Stijn Van de Vondel: 'The wettest summer since measurements began was a scientific windfall for our research, but the research questions relating to heat and drought remained unanswered. If we do get a heat wave over us in 2022, then we can record two extreme weather patterns. As a researcher, this is a bit of a naughty wish; from a human point of view, it is obviously not desirable for our population to experience a heat wave. If we get another unstable summer in 2022, it will provide interesting data, in terms of rain infiltration and groundwater. So the follow-up research is extremely relevant.'
Camille Allonsius: 'Our participants are also enthusiastic; of the 4.400 existing participants, 3.000 re-enrolled, while we were counting on at least 1.000 re-enrolments. We are also ready to keep these 3.000 citizen scientists engaged, no matter what the weather gives us.'