SoilTemp: towards a global map and database of soil temperature and climate

Short: we are looking for soil temperature data from all over the world for inclusion in our global database.

Many questions in ecology revolve around climate: what climatic requirements do organisms have, how do they survive in extreme climatic conditions, and – increasingly relevant – how do they deal with the rapid changes in climate we are experiencing?

Despite climate thus being a crucial component of today’s ecological research, we are still very much limited in the climatic data we have to our disposal to actually answer these questions, especially at the global scale. Most of the data we do have comes from weather stations (or interpolations based on those): coarse-grained data measured at two meter above the ground.

SoilTemp - soil temperature and climate

Climate and temperatures are and have always been a crucial factor in ecological research

For many organisms, however, these free-air climatic averages are far from relevant: many species operate at much smaller spatial or temporal scales, for example. Free-air temperature and climate patterns also differ significantly from what happens at the soil surface, or a few centimeters below it. For many organisms in the soil and close to the surface (soil micro-organisms, ground beetles, herbs, forbs, mosses or tree seedlings, for example) there is thus a large mismatch between the climatic data we have, and the climate they actually experience.

Soil temperature forest understory

For forest understory species, free-air temperature is meaningless, as temperatures at the forest floor will differ several degrees from what happens above the forest canopy

However, while the quality and resolution of free-air and surface temperature data at the global scale is rapidly improving thanks to elaborated networks of weather stations and satellite data, the availability of soil temperature datasets is still largely limited. That is the rationale behind our launch of SoilTemp, a global effort to develop a database of soil temperature data and build global maps of soil climate that answer to the pressing needs of modern ecologists.


For alpine species, temperatures close to the surface are what matters, especially in winter, when they can hide from the frost under a protective snow cover

Yet for such a global effort, we will need your help! If you feel one or more of the following statements apply to you, please e-mail jonas.lembrechts [at] for more information:

1) You have georeferenced soil temperature data (0 till 10 cm below the surface) for a period of at least 1 year with maximum a 4-hour interval, and would like it to be part of this open access global database/map.
2) You have associated species (plants or other taxa) composition or trait data from the same location.
3) You know other possible partners with interesting soil temperature datasets, or working on similar topics, who might be interested in collaborating.
4) You are interested to be involved in this project in any other way.

Small and cheap temperature loggers (like these iButtons) have recently made such a global-scale endeavour as ‘SoilTemp’ possible

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Smart bud(die)s

Smart bud(die)s, or Knappe k(n)oppen in Dutch, is a citizen science project initiated by our research group at the University of Antwerp (together with ReaGent). It is tailored towards high schools, and aims to provide them with a fun and instructive way to be part of a real scientific experiment. In this case, aim is to study the budding of trees (hence the name), and the effect of daylength and climate on this budding.


Bringing a classroom in the forest: citizen science as it should be

Last week, I spent half a day in the forest with one such enthusiastic group of highschool students, and the dedicated scientists from our research group who introduced them to the forest. The goal that day was to slowly build up their knowledge of and interest in forests: first show them in general what a forest is, why it matters in the light of climate change, and how scientists like us are studying these forests.


A litter trap: capturing falling leaves to study the effect of climate and weather on forest dynamics

The students got to make their own preparation of leaves to study under a microscope, explored the different measurement devices spread throughout the forest (which is a dedicated ICOS long-term research site, and thus closely monitored on all levels), and learn a range of facts from photosynthesis to heathland management. They got to run through the forest, and admire its mushrooms. All of it to get them involved and fascinated about the trees they will be studying next.


A student counting bubbles in the water as a measure of photosynthesis

Such community-driven science is very different from how science is traditionally done, at the far end of the spectrum one might consider when thinking about scientific outreach. It is putting science and the community into one pot and stirring it vigorously. The resulting dish tastes fascinatingly refreshing: children who get to learn about science while doing it, who experience how to care about the world that surrounds them, and look at it with curiosity.


Learning about forests and their role in climate change in one of the best monitored forests of the country

It is a huge commitment for the involved scientists, that much is certain. But it serves one of the main goals of science, and as such is worth as much effort as any experiment.


Heathland management and why it matters


When science and society come together

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The beginning of this week brought me to Dovre, a stunning National Park in the center of Norway.


The viewpoint on Snøhetta in Dovre

The area is sitting a 2,5 hours of steady uphill driving south of Trondheim, and was covered in a beautiful November snow blanket.


A little juniper sticking its head through the fresh November snow

Yet the beauty and the vastness of the place were not the reason why I went there. No, that reason was science: we met with a team of 4 to officially launch our recently started PhD-project on the effect of trails on mountain vegetation.


Hiking up a trail in winter will affect plants in summer

The 3 days of discussion turned out to be the kind of meeting every scientists dreams of once in a while: little distractions, just brainstorming with fascinating ecologists about what could be happening along our mountain trails – and how we could figure that out.


Tea and talks with a view

We all are very much looking forward to the coming 3,5 years, with fieldwork both in this area and higher north, in Swedish Lapland. If all goes well, these years will teach us how hiking trails affect the vegetation in our mountains, and what we should do about it.


Betula nana

Exciting times ahead!

More pictures of Dovre on the right of this blog.


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Food on the move

On this blog, we mostly talk about how global change is causing species to go ‘on the move’, towards areas where they do not occur naturally. For this post, however, I’d like to turn that perspective around, and talk about another type of species movement, one that is a large part of this global change: the transportation effort needed to bring your food from farm to plate.

Most of all, I want to highlight here an alternative to this #FoodOnTheMove: short-chain farming and community-supported agriculture.


This week, our local community-supported farm distributed this autumn’s potato harvest among its members. I got to take home a nice 17 kg – and one tomato that was looking to perfect to let go.

CSA – or community-supported agriculture – is an agricultural system that aims to connect producer and consumers more closely. Usually, one subscribes to the harvest of one farm or a group of farms. CSA is also on the rise in Western societies, and below I would like to make a strong case why I think that is a good thing.


Anticipating a summer full of beans at our local CSA-farm

Based on my own experience, CSA is beneficial to me – and the world – in a wide range of ways:

  • First of all: the environmental gain! A largely plant-based diet is already a big plus for the environment compared to a meat-oriented one, but if those plants are being brought in from far away (or grown in heated greenhouses), there is a substantial environmental cost associated with them. Short-chain farming largely cuts out that transport chain, and the environmental cost associated with it. Moreover, a farm with a diversity of vegetables, as opposed to the kilometers long monocultures seen in industrial farming provides a certain advantage for biodiversity, as does the space gained in third-world countries if you don’t let your food fly in.
  • Delicious vegetables, and an un-dreamed variety of them. Vegetables coming fresh from the soil are just that much tastier than their packed and transported shop counterparts. At our farm, there is also so much choice that one is much easier ‘tricked’ into discovering less-known vegetables.


  • Following the season: CSA can teach you again how it is not to have all vegetables available in each season. We now follow ‘earth’s heartbeat’ again, instead of having the same common vegetables all year round. The latter also has a big environmental cost associated with it, as the off-season versions of vegetables often need a serious energy investment.
  • Get out in the field: often, CSA-farms offer their community the option to help in the field, harvest their own vegetables, or assist with planting and weeding. While this is a great way to get your mind empty, your longs clean and your hands dirty, it also brings back the connection with nature and what you eat. To me, it also thought me how much effort is needed to feed the world as a whole (and me in particular).

Volunteering on the farm to plant onions is a joy. Eating your ‘own’ onions a few months later even more so.

Any downsides to this way of farming? The price perhaps, it is obviously not as cheap as what you would find in the supermarket, and – at least in our case – you pay up front at the beginning of the year. The latter implies that a bad harvest is also carried by the community.  The cost for the farmer is another thing: this type of agriculture usually implies a large personal investment from the farmer, not in the least regarding time and energy.

That aside, I do think that CSA can and should play a major role in how we live our lives in the future.

For the locals: I can totally recommend our CSA-farm ‘de Plukheyde‘ in Kampenhout, Belgium.

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The Tundra Trait Team

In ecology, it is not only relevant where a plant is growing (as is the usual topic of our research here), but also how it looks like when it grows there. The latter is reflected in the concept of traits: characteristics of a species’ ecological strategies and life histories, underlying differences in the way species acquire and use resources. For plants, these traits could reflect values related to their size, nutrient acquisition or seed production.


Measuring the height of an individual of Matricaria discoidea in a roadside

Such traits reflect the direct interaction between a species and its habitat, even more than their presence or absence at a certain location does. Variation in traits is thus often closely linked to environmental variation, like changes in climate.


In the high tundra (like here in the northern Swedish mountains), plants usually stay close to the ground, as illustrated by this Salix herbacea in a soft moss bed.

In order to analyze large-scale effects of the environment on plant performance, however, a lot of trait data is needed. But here is the great news: countless scientists are collecting such data all over the world. The trick is just to bring all this data together. The TRY-database does a great job in that regard, yet that database had a big and important limitation: the Arctic was highly underrepresented. A new effort (led by Anne Bjorkman and the Tundra Trait Team) has now filled that void, by collating a database of over 90.000 (!) data points about plant traits from tundra vegetation.


Measuring the Specific Leaf Area of the Arctic birch (Betula pubescens czerepanovii)

That is a lot of trait data, and the possibilities with such a database are virtually endless. We can use it to see how species react to climate across the whole tundra biome, for example, which can shed important light on how the tundra vegetation will be (and is) reacting to the changing climate. The latter is illustrated in another recent paper from the same team in Nature, in which Bjorkman et al. explore the relationships between temperature, moisture and plant traits across the whole tundra. Their conclusions? Plant height is rapidly increasing with the warming climate in recent decades, yet most other traits are lagging behind.


Thalictrum alpinum, a small alpine version of a genus with usually tall-growing species

Another example of how scientists are teaming up everywhere to tackle issues that are to big to handle alone. And that’s exactly how I love it.


Tall, woody species (like this pine, Pinus sylvestris) only occur up till a certain elevation and latitude


Bjorkman et al. (2018) Tundra Trait Team: A database of plant traits spanning the
tundra biome, Global Ecology and Biogeography.

Bjorkman AD, IH Myers-Smith, SC Elmendorf, S Normand, N Rüger, et al. Changes in plant functional traits across a warming tundra biomeNature. DOI:


Astragalus alpinus

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It is that time of year again: the course on plant stress for our master students at the University of Antwerp (as I also wrote about previous years).

This year, the practical part got a long-anticipated upgrade. It is now framed within a new course called ‘Plant and soil ecology’, which is thought to the master students in Conservation Ecology and the very new masters on Global Change Ecology. We could now also step away from teaching only about chlorophyll fluorescence as we did the previous years.


The new set-up of the practicum, featuring the fluorometer to measure chlorophyll fluorescence on the left, the pressure bomb in the middle, and our little friend Dualex Scientific+ on the right. 

Now, the practicum is about plant stress in general, and we use it to highlight different ways in which ecologists can measure stress. Students get to try 3 different methods – using the traditional fluorometer I always used, but also a very practical tool called the Dualex Scientific+ that rapidly measures chlorophyll and pigment content in the leaves, and a pressure bomb, that allows them to assess the water status of plants by putting pressure on a leaf till water emerges.


Measuring chlorophyll content with the Dualex Scientific+ in a project on the effect of Urban Heat Islands on non-native plant species in Flanders

The practicum thus now truly reflects the wide range of opportunities ecologists have to get answers to this fundamental question in our field: how happy is this plant? And I truly hope the students find that knowledge inspirational for their future careers as conservation biologists of global change ecologists.

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Website updated

As I officially started my postdoc this month, it was due time to update the content of my website. As from today, this website has officially completed its transformation from a personal blog narrating the personal thoughts and adventures of a PhD-student into a platform displaying the research of me and my main collaborators.

You can now see this reflected at the top, where the menu is streamlined into 3 main headings:

  • About: details on me and my scientific goals, with now a big section on my closest colleagues.
  • The science: the main research section, consisting of two parts:
    • Main conclusionsa brief summary of the main outcomes of our research, sorted by topic.
    • Publication listan overview of all our published papers up till now, with for each of them a link to a blogpost summarizing the results.
  • Blogstill the main part of the website: updates on all the science we do, and adventures we have in search for answers.


My faithful followers do not have to worry, as for you, not much will change: you will still get a steady stream of adventures across the globe, and cool scientific results brightened up with pictures. Yet for new or accidental visitors, it became much easier to grab who I am (/who we are) and what scientific questions we answered so far.

I hope you like the change!

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Study day

This week, we gathered in the beautiful city center of Antwerp for the PLECO Research Day, a yearly event that brings together all members of our research group for a day of discussions.


The towers of the church of Saint Joris above the Elzenveld, our meeting venue for the day in Antwerp.

As our group is steadily growing (over 60 active scientists now, with 4 professors at the steering wheel), such a yearly check-up is vital for the lab to keep running smoothly. It helps us to keep in touch with what the others are working on, and see how the group is moving forward, but it also gives the opportunity for new faces to get an overview of who is who, and what is what. It also serves as a necessary reminder for easy-to-forget lab rules.

Most importantly, for me, it provides the opportunity to seek for in-house expertise, which might otherwise be overlooked. With the topics I am focussing on being slightly detached from what the rest of the group is working on, it is tempting to seek partnerships across the globe. But oh the blessing when you realize the necessary expert is just sitting 3 doors away from you!


The ‘Zuiderpershuis’ in Antwerp, on my early-morning commute to the meeting

An excellent belated kick-off of the academic year, so to say.

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