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.

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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.


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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.


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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

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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.

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The much-anticipated spring of 2018 finally made it to Belgium!



Not only because I have been craving to see my beloved plants resprouting, after a long winter of being ‘green-deprived’, but more importantly because this spring I will finally defend my PhD.



Today, I officially submitted the final version of the thesis document to both the jury and the printing press, and I can tell you I am more than proud of the final product: 226 pages summarizing 5 years of thinking.


Carpinus betulus

Now I have a surprisingly large chunk of time on my hand, with for once no major deadline on the horizon (if we ignore the public defence at the end of the month). Spring thus also brings the freedom to dive into my favourite scientific topics for the future, and that feeling of choice is almost as beautiful as the delicate flowers in these pictures.



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

Scientists have been wondering for a long time why some exotic species become invasive while others do not. A new paper we just published on invasive and non-invasive plant species in Belgium reveals that the answer should be sought at the smallest scale. The authors, a team lead by ecologists from the University of Antwerp, indeed showed that there is a lot of variation in conditions at the local scale, and that each different habitat favors different traits in the exotic species. The exercise revealed many of the standard culprits that make habitats vulnerable (like temperature, light availability, native plant species diversity and soil fertility) and non-natives successful (like plant size, photosynthesis ability and nutrient status), yet invasive species were much better at matching their traits with the environment at the local scale than their non-invasive counterparts. Most invasive species indeed managed to produce many more seeds than the non-invasive species, and that even in habitats normally considered less easy to invade, as long as they locally had the correct trait arsenal to deal with these aversive conditions.


Invasive plant species, like this Impatiens glandulifera (Himalayan balsam) in Belgium, often produce many more seeds than their non-invasive counterparts, yet their invasive success largely depends on finding the perfect match between their own traits and the local site conditions.

This shows that the fight between invasive plants and the native vegetation is likely to be won at the smallest scale, with invasive plants cherry-picking sites that best match their characteristics. Unfortunately, it also means that predicting the invasive success of plant species did not become any easier. Yes, exotic plant species with a higher seed production are much more likely to be invasive, yet this seed production itself is at the small scale highly influenced by the match between both habitat conditions and the other traits of the plants. And as the study shows, this local match-making often has some surprises up its sleeve.



Fallopia japonica (Japanese knotweed) has been a highly successful invasive species in Europe, partly due to its flexible adaptation to different environmental conditions.


Lembrechts JJ, Rossi E, Milbau A, Nijs I (2018). Habitat properties and plant traits interact as drivers of non-native plant species fitness at the local scale. Ecology and evolution.

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