The 3D lab

From Alaska to the Alps

Posted on January 6, 2017 by lembrechtsjonas

Some very good news from our colleagues working on the Tundra Tea Bag experiment! The nice big blob on their map in Sweden/Norway, that’s us. Very much looking forward to the global results.

tundra teabag experiment

The year is ending and the data is in…and there is a lot of it!

Thanks to the great efforts of all those working on the tundra teabag experiment we have over 4,000 tea bag decomposition samples, spanning more than 350 sites around the tundra. And there’s still more to come.

teamap2 Teabag sites capture differences in decomposition right across the tundra biome

With 2017 just around the corner the analysis has now begun, testing three questions:

Does environmental variation do a better job of explaining decomposition than the type of tea? Or does decomposition rate just depend on what is decomposing?
How does decomposition of tea change over time and between the seasons. Arctic winters are cold, dark and long; does that mean decomposition only happens in the summer?
What aspects of the environment most affect decomposition rate? Is it temperature, moisture, surrounding vegetation, or something else?

With such a great…

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An overview – part 2

Posted on December 30, 2016 by lembrechtsjonas

In these closing posts of 2016, I want to give you a quick (and slightly biased) overview of everything what happened this year, based on the ten most appreciated posts on this blog for this year. This is part two.

While the first half of 2016 had had a big focus on fieldwork, learning skills and optimising plans, the second half was mostly dedicated to the wrapping up of stories. Publishing. Outreach. Telling a story. We are learning important things about how our world functions in this project, and we want these things to be known.

Here are my 5 highlights for the second half of the year:

The little hut in the forest: This summer, as every summer since 2012, we went to the high north to gather more data. Our exotic destination: Lapland, the subarctic part of Scandinavia, where summers are short, yet with plenty of sunshine. Thanks to great collaborations and a good research design, less than three weeks of adventure every year results in enough data to keep us busy. A blessing!

Closing chapters: When you finally read the output of your work in the newspapers, it feels like you are closing a chapter. Discovering something, and getting the opportunity to tell the world about it, that is what science is all about! Telling stories; stories built on facts, yet exciting enough to enchant the reader.

Cornus suecica

The modern botanist: it was 2016, so even ecologists need to keep up with the times. The digital age is undeniably upon us, and we should take advantage of it! 2016 thus brought the increased implementation of modern technology in our fieldwork: tablets for data input in the field, digital pictures for plot recognition, a picture-recognition app to aid in plant identification and an app with which anybody (yes anybody!) can help us collecting data. Go digital, or go home!

How hikers can help science: For that specific citizen science project, we make use of the app iNaturalist – or your gps – to record a selection of plant species every time you see them along a mountain trail anywhere in the world. This surprisingly easy design will help us getting global information on how humans move species along mountain trails, without the need for us to travel everywhere ourselves. You are warmly welcomed to help us next time you are in the mountains!

Where we disturb nature, the invaders quickly follow: How better to finish this series on the highlights of 2016 than with our last paper: an intercontinental experimental collaboration between Europe and South-America, that recently got published in the Proceedings of the National Academy of Science of the USA. An experiment that answered many of the questions we had about plant invasion in the mountains, yet created enough new ones to keep us busy in the next year. So now on to the next one!

Hoping to see you all here again in 2017, with more exciting science. As for now, thanks for reading.

Posted in General | Tagged 2016, Ecology, Landscape photography, Landscapes, Mountains, Nature, New Year, PhD, Scandinavia, Science | 2 Comments

An overview

Posted on December 27, 2016 by lembrechtsjonas

In these closing posts of 2016, I want to give you a quick (and slightly biased) overview of everything what happened this year, based on the ten most appreciated posts on this blog. This is part one.

2016 has been an important year for the science here On Top of the World. The year brought a high in- and output, with sessions of highly successfull fieldwork, international collaborations, a few scientific publications, and outreach to the larger public as a cherry on the cake. At 3 years and 3 months in the project, the efforts are finally truly being rewarded. Here are 5 of the highlights:

The cathedral of Amiens, France

The princess of the north: January started bright, with a visit to colleagues in Amiens, France. The visit lasted no longer than a week, yet sometimes even a few hours in the presence of someone with more experience results in a leap forward with your own work. Statistical tricks and climatic models, a lot of what I am still doing now had its origin there in Amiens.

Temple on top of Le Grand Donon, a peak in northern France

Lessons from history: Topic-wise, the whole year has been about disturbance. Humans intervening with nature, changing its balance and the cascade of effects that results from such disturbance. This disturbance has been around as long as humans have, as shown by the temple on top of Le Grand Donon in this picture. Yet recent increases in this disturbance, together with an inevitable climate change, results in impressive changes all over our natural world. We want to find out what will do to the plants.

Experimental litter in bags in beech forest in Denmark

On how leaves decompose: While we originally focussed on aboveground processes within this project, I got more and more convinced this year that a big chunk of the important stuff actually happens in the soil below our feet. We are digging deeper and deeper, looking at how fast the soil breaks down plant material, how fungi in the soil affect where plants can be found and if the climate at soil level is actually much more relevant for plants than what we usually use.

Gravel road through Torres del Paine National Park in the Chilean Andes

Plant traffic along mountain roads: With MIREN, the Mountain Invasion Research Network, we look at mountain roads and how they affect plant species distributions. They facilitate plant invasions, we knew that, but it turns out that roads are also busy with native species travelling both up and down the mountains. These travels in both directions were shown in our paper in Ecography.

Young beech leaves with a bluebell field in the background

Beech and bluebell: Research also involves teaching the next generation of scientists, one of the most beautiful parts of the job. My favourite way of doing that is by showing the students the magic of the Hallerbos, the mythical and world-famous bluebell-forest close to Brussels. Every spring, we send them on an exploratory day through the forest to learn about the interactions between soil and vegetation and how to learn a lot about a system by just looking at the plant species.

More soon on the peaks of 2016 on top of the world!

Posted in General | Tagged 2016, Ecology, Flowers, Landscape photography, Mountains, Nature photography, Overview, Photography, Plants, Science, Trees | 1 Comment

Wave out the year

Posted on December 24, 2016 by lembrechtsjonas

Take a step back. Wave out the year. Cherish your treasures. Take your time for it…

These buzzy burrs (Acaena magellanica) put on some festive hats to celebrate the end of the year with you. And admit, the name buzzy burr is already festive on its own.

Soon, there will be a new year, with plenty of new possibilities.

But for now, it’s Christmas! Now we can just be happy with what the previous year has brought. And for me, that was lots to be happy about (the summary here)!

Posted in General | Tagged Christmas, Flowers, Holidays, Landscape photography, Nature, Nature photography, Photography, Plants, Snow, Winter | 1 Comment

The stunning truth behind the graph

Posted on December 15, 2016 by lembrechtsjonas

Graphs often hide a lot of intriguing information, yet it is not always easy to get to what really matters. In ‘behind the graph’, I put in the effort to explain one of the main findings of our research and get to the stunning truth hidden in those simple lines.

This truth has been known for years: the higher you get into the mountains, the less non-native plant species you will find. They are common in the lowlands, gradually disappear towards higher elevations and are completely absent at the top.

Non-native plant species diversity virtually always decreases with increasing elevation in mountains.

That was hence exactly the pattern we expected to find when we decided to put these observations to the test in mountains close to the north- and southpole. A nice declining curve: the higher we got, the colder it would be and the lower our study plants’ success.

Putting the observations to the test with a seeding experiment in the mountains in northern Sweden (here) and southern Chile.

You will have to imagine the surprised looks on our faces when what we found was something completely different from theory. You’ll have to check for yourself on the graph:

Probability of invader establishment as a function of elevation in subantarctic Chile in disturbed (red) and undisturbed (black) plots.

Quadratic! The pattern we discovered turned out to be quadratic! Fascinating, isn’t it?

This means that the invaders actually perform worse at the elevation where they are most likely to be found in highest numbers at the moment. Their chances of success only rise to a maximum around the tree line (which is close to the highest elevation where they are currently found).

This quadratic function means that there is not one, but actually two different processes limiting invader success along the gradient; one at the top and one at the bottom of the mountain.

The higher you get, the colder it becomes. A day in the beginning of september at a 1000 meters in the Swedish mountains.

The one at the top is the easy one: the higher you get, the colder it becomes and the lower the chances for the non-natives to survive (who are not used to such cold from their home range in Western Europe).

Fresh snow on a plot close to the tree line in subantarctic Chile

The limiting factor in the valley is more intriguing, though. To understand what happens there, we need to take a look at our little graph again. As you can see, we have lines in two colours, a black and a red one. The black line displays the results from seeding non-native species in intact, undisturbed vegetation. Surprisingly, virtually none of them managed to germinate, nowhere along the elevation gradient. This implies that the vegetation in these cold mountains is highly resistant to invasion, at least when left alone and undisturbed.

The dwarf shrubs, grasses and sedges of the subarctic vegetation are not welcoming to intruders, at least not when left alone.

Our red line, which nicely shows the quadratic relationship, is for seeds sown in disturbed plots, where we removed the native vegetation as happens in roadsides, along trails or with construction works. The positive effect of this disturbance on the non-native species is astonishing: create a gap in the native vegetation and the resistance to invasion drops dramatically.

That is, it drops most dramatically at intermediate elevations, where temperatures are not too cold yet, but the native vegetation also fails at regrowing again. At low elevations, where we saw the unexpected drop in performance, the native vegetation manages to regrow fast enough to limit the success of the invaders.

Disturbance events like mountain trails are a blessing for non-native species coming in.

So why is there this big differences in the expected and observed trend? The key lies in the amount of seeds that come in: at the moment, there are many many more seeds of non-native species at low elevations, which trumps the fact that they have lower chance of success. Yet that information predicts a grim future: if more seeds make it to higher elevations, and we keep messing around with disturbance of the natural vegetation like we currently do, plant invasions will rapidly increase in the very near future.

All of that in one little graph!

Trifolium pratense, a non-native species in the high north

Source: Lembrechts et al. (2016) Disturbance is the key to plant invasions in cold environments. PNAS.

Posted in Science | Tagged Climate, Ecology, Experiments, Landscape photography, Landscapes, Mountains, Nature, Plant invasion, Plants, Science | 3 Comments

Happy International Mountain Day!

Posted on December 11, 2016 by lembrechtsjonas

Today – the 11th of December – is International Mountain Day, the yearly celebration of mountains since 2003.

A hotel in the beautiful Patagonian Andes in Bariloche

A day on which we try to increase awareness for the importance of mountains for all life on earth. A day to think about the opportunities and constraints that come with mountain development and conservation. A day for mountains, yet as much for all of us.

A ski lift in the National Park of Abisko in Northern Sweden

A day to share some beautiful pictures of mountain views, but more importantly, remind us all of the impact we as humans have on these mountains.

Peace and quiet in a little valley in northern Norway

More than ever, we will have to search for a balance between nature and culture, between ecology and economy, between what we need, and what the mountains need.

Enjoying the view from the top of a mountain in the Northern Scandes

With every step we take in the mountains, we disturb them, and this disturbance has a cascade of effects, that we might never be able to grasp fully. It is a fast change, that is often irreversible, and like all changes in nature, it comes with winners and losers.

Wooden signs marking a snowscooter trail in a green valley in northern Sweden

Our research for example has shown ample times how humans and their disturbances in the mountains play a leading role in changes in the vegetation, with changing distributions of plant species and the introduction of many non-native intruder.

Yet the winners are similar – often even the same – everywhere around the world, making all disturbed sites looking more and more like each other. And that is a big loss for biodiversity.

You can always check our conclusions on the page ‘PhD-cv‘.