Collective science is the best science

When scientists (or people in general) work together, magic happens. I am a dedicated advocate of that policy: if a lot of people all do a little bit of work, the level of interest of the results skyrockets.

I was pointed towards another one of these collaborative approaches: our dear colleagues in Amiens are trying to gather leaves from a few typical forest species from all across Europe (you can find all information on the project on the blog of Jonathan Lenoir, co-supervisor of the project).


Beech forest (the Hallerbos, Belgium)

The goal is to disentangle the historical processes that drive the distribution of two common forest species (Geum urbanum – wood avens, and Oxalis acetosella – wood sorrel). For that to happen, they need a lot of leaves, from everywhere in Europe, from the Mediterranean till northern Scandinavia. And instead of travelling the thousands of kilometers needed to get the data, they call on everybody they know – or don’t know yet – in Europe to help them out.


Oxalis acetosella, or wood sorrel, in the Hallerbos, Belgium

The fieldwork is super easy: if you see the plant whenever hiking in a forest, just collect some leaves from 15 or more individuals, put them each in a separate envelop, and send them by mail to Amiens, where they will be analyzed further. See: easier is impossible. And yet, if enough people participate, we can answer fundamental questions on the distribution of forest species, and how these distributions change over time.

My first population of Geum urbanum is already ready to be mailed!


Envelopes filled with leaves of Geum urbanum, ready to be send to the lab in Amiens!

(Not hiking in the forest, but in the mountains? Don’t forget about our MIREN trail survey, we still welcome all help!)

Posted in France | Tagged , , , , , , , , , | Leave a comment

An important tool in the toolbox

Last week, I had the opportunity to teach the students of our third Bachelor in Biology a little lesson about vegetation surveys.


Grassy meadow on the university campus, the perfect spot to learn about vegetation surveys

It was a half a day course in the framework of their course on Good Field Practices, in which we try to give them a good toolbox on how to perform ecological fieldwork.

Crucial tool in the toolbox of a plant ecologist? The vegetation survey! Especially in my branch of ecology, in which we look at the effects of global change, vegetation surveys are key. Global change has strong effects on the distribution of species, but without surveying where species are actually growing, it is impossible to conclude anything meaningful.


The pin-frame method, in which the researcher drops a pin at regular distances and writes down which plants it touches

Going outside and establishing a basic knowledge of common plant species is thus important, even in these modern times in which many ecological questions are answered from behind a computer. Someone needs to go out in the field and record where the plants are growing, indeed. There are botanists we can trust with that task (and oh, how much credit do they deserve in todays’ ecology!), but how to understand your system if you have not gone out in the field to experience it yourself?


Ranunculus acris

It is also important to know the strengths of weaknesses of different types of vegetation surveys: some are fast (just estimating a percentage cover), some are more meticulous (like the pin-frame method above). All of them have a significant amount of noise, as the students found out quickly enough when trying to repeat each-other survey. Yet despite all that noise, survey method and observer differences turned out rather robust. Some rare species might be missed with one method or the other, yet common species always emerge as common.

The students hopefully took an other important lesson home: looking at plants can be a lot of fun, but vegetation surveys are as ‘serious’ science as any other scientific approach. Another tool in the toolbox that a good plant ecologist needs to keep sharp.


Posted in Belgium, General | Tagged , , , , , , , , , | Leave a comment


The Mountain Invasion Research Network now has its own official mascot: a grass! A newly discovered Poa-species got named after our network, carrying the Latin name Poa mireniana. Poa mireniana is a slender stoloniferous grass, with leaves with a broader and coarser character, a longer ligule, and usually more numerous florets than its nearest relatives. For those less accustomed to botanics: it is a quiet elegant and attractive specimen, and we are very proud of it.

Poa mireniana

Some distinctive characteristics of Poa mireniana. (c) Ian Clarke

MIREN got the honour of the naming, as the species was discovered during the MIREN surveys in the Kosciuszko National Park in southeast Australia, where botanists are following the roadside vegetation in the framework of our global survey. There, the species was encountered in steep mountain forests at around 1000 m above sea level, where it baffled the botanists with its undocumented characteristics. It serves as a beautiful illustration of how monitoring work such as that of MIREN not only documents trends in biodiversity, but also unearths new diversity.


Kosciuszko National Park, where the new grass species was discovered during surveys of the native and non-native roadside vegetation. On the picture a ‘snowy hill’ covered in ox-eye daisies, a wide-spread non-native species in the park. (c) K. McDougall

Find all information on our new mascot here.

Posted in Australia, General, Science | Tagged , , , , , , | Leave a comment

Sowing the seeds

This weird-looking bunch of office plants is actually much more than it seems: it is the start of a new experiment, which will broaden our scientific horizon to the world of population genetics.

The lucky model species is Matricaria discoidea, an easy-to-overlook relative of camomile with an interesting pineapple smell to the leaves. Our dedicated PhD-student is harvesting populations in cities and rural areas all over Belgium now. Soon, we will be sowing their seeds to follow-up their performance in different environments.


Posted in Belgium, Uncategorized | Tagged , , , , , , | Leave a comment

A PhD-summary

Good news! My PhD is successfully defended, and the main message I wanted to tell to the whole world is now out. Extra good news: I published a little booklet for those who want to know what my work is about, summarizing my PhD with the help of the blogposts I published here throughout the years. You can buy the book at

Website blog-PhD

You can read the published chapters here as well, each of them linked to a paper we published throughout my PhD:

Plant species are on the move, and it is us humans who move them – on the role of humans in the changing distributions of mountain plants


Chapter 1
Changes in the mountains – on the effects of roads on mountain vegetation
More about roadside vegetation – on changes in these road effects with elevation
Aliens and their way to the top – on non-native plant invasions along mountain roads
Escaping the roadsides – non-native plant invasions into the undisturbed mountain vegetation


Chapter 2
A small-scale dilemma – on the highly local effects of disturbance on climate and plants.

Chapter 3
Plant traffic along mountain roads – on the up- and downward shifts in species distributions in mountain roadsides.

Chapter 4
Where we disturb nature, the invaders quickly follow – on the experimental disentangling of the drivers behind plant invasion in mountains.

Chapter 5
A story of hotspots and stepping stones – on how plants can use warm microclimates to travel uphill.

Garden angelica flanking mountain road

Chapter 6
More. Higher. Faster. – on the global increase in non-native species above the treeline.

Chapter 7
Matching the plant with the environment: what makes invasive plant species so successful?

Chapter 8
An easy solution to a complicated issue – on the effects of species evenness in biodiversity experiments.

Chapter 9
On how leaves decompose – on the effect of local climate on leave decomposition.


Posted in General, Science | Tagged , , , , , , , , | 1 Comment

Field season kick-off

Hallerbos - 7

Allium ursinum, wild garlic

Last week, we celebrated the kick-off of 2018s field season, and as usual we did that with a student field trip to the Hallerbos, the world-famous purple forest that gets filled with bluebells in spring.

Hallerbos - 12

The Hallerbos, close to Brussels, Belgium, on an unfortunately cloudy day

We like to take the students of the course on ‘Ecosystem Types’ to this forest. Not just for its international fame, but more importantly for the clear differences in forest types that we find there. The loamy top soil layer has been eroded, revealing sandy hill tops, and accumulating rich loam in the valleys.

Hallerbos - 10

Pre-flowering Convallaria majalis, a typical species for drier forests

This geological history results in clear gradients in soil nutrients and moisture on a scale of often just a few meters, with massive effects on the vegetation. And as I love how the microscale affects species occurrence, this is a great example to show the students.

Hallerbos - 1

Hyacinthoides non-scripta, the famous bluebells

Hallerbos - 14

Where the nutrient rich forests of the valleys slowly start creeping uphill, we can find wild garlic and bluebells growing together

So we kick it off in spring with the spring flora that is so typical for Western European forests. Then slowly, over the next months, we will be moving our attention up north again, ending in northern Scandinavia in July. As usual: exciting times ahead!

Hallerbos - 3

Delicate flowers of Allium ursinum

Posted in Belgium | Tagged , , , , , , , , , | Leave a comment

Plant species are on the move, and it is us humans who are moving them

Today, I am finally defending the results of all these years of hard work. For those who cannot join me in the celebrations at the University of Antwerp, here is – in short – the message I want to tell the world.

Garden angelica flanking mountain road

Angelica archangelica along mountain road in the northern Scandes, Norway

Human actions are having a significant impact on the distribution of plant species, and locally even more so than the warming climate. It is the surprising outcome of the PhD-thesis from University of Antwerp-based Jonas Lembrechts, who is studying plant species distributions in cold-climate mountain regions.

Yes, the warming climate is shifting the distribution of plant species poleward and to higher elevations, but our actions are causing even more rapid and structural changes to where species can be found. In his PhD, Lembrechts showed how humans are helping non-native species to invade mountain regions: “Humans are taking non-native plant species with them all over the world, introducing them to other mountain regions. Once there, these species can profit from human structures like mountain roads to move rapidly to higher elevations,” Lembrechts explains.

But it is not only new species who hitchhike on our mountain roads; native plant species use them as well. “I discovered that mountain roads host busy plant traffic from native species as well,” says Lembrechts. “The local environmental conditions in roadsides help many native species on their way to the top, and alpine species even use them to move downhill.” He indeed uncovered important heterogeneity in local conditions that had largely been ignored in the assessment of species distributions: local climate and soil conditions – crucial to plants – can often vary more on a scale of centimeters to meters than across a whole elevation gradient. And human disturbance is a crucial driver of such heterogeneity.


Mountain roads – here in the Chilean Andes – and other anthropogenic disturbances have a large effect on the local environment, and consequently on regional plant species distributions.

Anthropogenic disturbances like these mountain roads thus help plant species to move hundreds of meters up and own the mountains, a magnitude of ten more than they have moved due to climate change. These results suggests that we are largely underestimating the direct effects humans have on the distribution of species. That is why Lembrechts warns: “climate warming is having a large – and accelerating – effect on the distribution of species globally, but it should not let us underestimate the direct effect of human disturbance locally.” For mountain conservation, it is crucial to concentrate human presence: urge tourists to stay on the trails, and leave our remaining pristine mountain nature as undisturbed as possible. Only then, we can give the mountain vegetation the necessary room to deal with climate change itself.

Posted in Science | Tagged , , , , , , , , , , | 8 Comments