Dark

Dark clouds over our Dark Diversity experiment, yesterday.

An unstable atmosphere – some thunderclouds passing to the north of us – made for dramatic views of the heathland in the ‘Kalmthoutse Heide’, when we were out there collecting data for the Dark Diversity Network.

It made for apocalyptic views at our disturbed site, where we measure the impact of anthropogenic disturbance on the dark diversity – the species absent at a certain location. In our case, the disturbance had been dramatic, as proven by the picture above, yet with a noble goal in mind: turning a pine forest back into heathland – the target vegetation of the area. We aim to monitor over the years how the vegetation will recover from that drastic disturbance.

A thunderstorm passing in the far distance over the heathlands of northern Flanders

Those target heathlands were showing themselves from their best sides in many of our other plots, proving once again that the Kalmthoutse Heide is one of the crown jewels of Flemish nature. If ever in the area, I strongly recommend you to visit them, especially towards the end of August, when the vast plains turn beautifully pink!

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Just too early for the pink Calluna-fields of late summer

Oh, and don’t worry about those clouds – modern technology lets one track the weather with an accuracy of a few minutes and meters, so plenty of time to go into hiding long before things get awry.

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Heather

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Early flowers of Calluna vulgaris in the Kalmthoutse Heide. Hoping for more in the coming months!

While most of the fieldwork campaigns this summer are being taken care of by our awesome teams of PhD and master students, there is a few sets of field days I am joining. One of them just happened on a lovely not-too-hot summer day in the heathlands and forests of northern Flanders, on the border with the Netherlands.

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Pine seedling braving a sandy dune

It is there, on the poor sandy soils of the Campina region, that we are monitoring vegetation for the global Dark Diversity project.

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The heathlands and forests of the border park

I have written about this intriguing ‘dark diversity’ before: it is basically the non-realised biodiversity, those species that are NOT present at a given location. It is those species that indicate the unrealised potential of an area. For this, we compare a disturbed and an undisturbed heathland site with a whole series of vegetation surveys in a circle with 20 km diameter around these plots.

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Species identification in a wet heathland plot

There is of course at least two reasons why a certain species does not occur at a location: the local characteristics (a dry heathland will never hold the same species as a wet heathland a few meters downslope), and anthropogenic pressures. By comparing a disturbed with an undisturbed area, we will be able to disentangle these two, and get closer to the heart of what human influence does to diversity.

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Mushroom in a little patch of chestnut forest

Of course, such general questions on the drivers of global diversity (loss) require a lot of data. We are just one factor in a big chain here: our Flemish heathlands are one vegetation type to be studied; ecologists all over the world are right now out in their own landscapes, doing exactly the same. Talk about feeling connected with the world!

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Skipper butterfly

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Adding soil temperature loggers to our Dark Diversity plots to link up these observations to our global SoilTemp-network: hitting two birds with one stone!

 

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The climate the organisms feel

Short: our recent review in Ecography got awarded as runner-up of the E4-award, the Ecography award for Excellence in Ecology and Evolution. To celebrate that success, I am re-posting the original blogpost that explains the story. More of an auditory learner? Check out this video abstract, in which I narrate the main conclusions of the story in 3 minutes!

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Ecologists like to know where species are living, and why. It is indeed one of the most critical questions in today’s ecology to ask what is behind the distribution of a species, and how that will be affected by global change. A highly popular tool in that regard are ‘species distribution models’ (SDMs), a statistical tool to link species occurrence data to data on background conditions.

Climate is a crucial background condition to consider in that regard, and climate variables are the most commonly used variables in SDMs. Yet there is a big issue there: what climate to use when modelling the distribution of a species? Ideally, one wants to use the conditions as experienced by the study organism, right? Traditionally, however, SDMs mostly rely on free-air temperature conditions with a coarse resolution (e.g. with pixel sizes of 1×1 km), as this has for long been the best data available. Such data however fails to capture the apparent temperature (cf. microclimate) as experienced by living organisms within their habitats.

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For mountain plants especially (in this case Pedicularis hirsuta in the northern Scandes), the climate they experience near the ground is far from what happens at 2m in the air.

There is indeed an important mismatch between the climatic data we have available, and the climate as experienced by many organisms. First of all, local variation in temperature is crucial in any habitat with a vertical component, like forests, mountains, or cities. In these environments, local temperatures can differ several degrees from the coarse-grained averages usually used. Additionally, 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), this mismatch is fundamental.

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Most organisms, being it plants, insects, soil microbes or many many others, live totally decoupled from the climate at coarse resolutions as measured in weather stations. (Pictured: Cepaea nemoralis)

But no worries, the scientific community is on it! Several studies have already made considerable progress in tackling this problem from different angles in their effort to solve that mismatch. In our recent review in Ecography, we show how 1) in-situ climate measurements with tiny sensors, 2) remotely sensed data (from satellites, airplanes, or LiDAR, which provides high-resolution 3D reconstructions of the environment) and 3) microclimatic modelling, are all bringing us closer and closer to the climate our study organisms actually care about.

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Several studies have been getting closer to modeling the actual climate experienced by species, for example by incorporating 3D-forest structures in models of climate on the forest floor. (Pictured: Crocus sp.)

We believe that instead of using all these approaches separately, we should combine them. We thus propose a framework that does exactly that: first of all, we suggest using a selection of appropriately-placed sensors, spanning a wide range of environmental conditions. Not too few, not too many. This real-time local data from exactly the location where your organisms live can then be combined with detailed measurements of the habitat 3D structure, for example derived from digital elevation models or airborne laser scanning to extrapolate it to the whole region. Finally, long-term records of free-air conditions from nearby weather stations can be used to extend your in-situ network through time. With this unified approach, we can obtain microclimatic data with the optimal resolution and extent – both in space and time – to accurately model current and future species distributions.

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Summarizing our framework on how to get relevant microclimate data for use in ecological models.

Yet the proof of the pudding is in the eating, of course. The framework is there, but now we are stepping up the game: we want to apply our concept on the global scale. Therefore we launched SoilTemp, which is a global database of soil temperature data, with a double purpose: 1) we want to model soil temperature globally, combining this database of in-situ measurements with remote sensing and microclimatic modelling, and 2), we want to use the database to improve our models of species distributions. More on that here.

Interested, and have some soil temperature data lying around? Don’t hesitate and get in touch!

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The concrete surface and tall buildings in cities create a unique microclimate that is highly different from large-scale climatic averages. (Pictured: Viola sp.)

Reference: 

Lembrechts JJ, Nijs I, Lenoir J (2018). Incorporating microclimate into species distribution models. Ecography. doi: [10.1111/ecog.03947].

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Four fronts

Summer arrived, and that means: fieldwork! And this summer, more than ever before, that fieldwork is spreading across the world. We will have four important fronts of research open this summer, and I aim to keep you updated about all of them as they unfold.

First, we have our team in Norway, in the mountains of Dovre. There, under the expert lead of PhD student Ronja Wedegärtner, we are looking at the impact of hiking trails on biodiversity. This project now has its own website!

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Dovrefjell, Norway, here still under its blanket of snow

Secondly, there is our team in Abisko, Sweden, with PhD-student Jan Clavel. There, the summer will bring a lot more insights on belowground interactions, while we will also greatly expand our microclimatic network in collaboration with the awesome people at CIRC (the Climate Impact Research Center).

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The long-term vegetation monitoring gradient of CIRC, which will be the scene of microclimatic research this summer

A bit closer to home, there is our work on the invasion of exotic plant species in our Flemish cities, led by PhD-student Charly Geron. This will be expanded with a study on dark diversity in the heathlands of Kalmthout.

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Measuring the stress of non-native species across the urban-rural gradient

And then finally, there is our lab component: the processing of root samples from all over the world (currently working on samples from Tenerife) is also in full swing. Less glamorous pictures, yet the results promise to make a splash.

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Cutting roots for the analysis of fungal DNA

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Fieldwork in the Argentinian Andes earlier this year, now being processed in the lab

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The Mountain Invasion Research Network

For MIREN, we are working on an awesome new blog series summarizing our scientific findings from the last 15 years for conservation, policy makers and the global public. This is chapter 1, so stay tuned for more! Originally posted on www.mountaininvasions.org.

In July 2005, a group of mountain ecologists got together near Vienna, Austria, to discuss what was at that time an unknown and hardly studied issue: the invasion of non-native plant species into mountains1. Up till then, mountain regions had mostly been considered resistant to invasion. Yet those times were changing,  and mountain areas were increasingly threatened by invasive alien plants.

That group of mountain ecologists in Vienna launched the Mountain Invasion Research Network (MIREN), following the cry that ‘now it is time to act’: by addressing the issue before it spiraled out of control, science could prove to be the gatekeeper of biodiversity in the fragile mountain world2.

The MIREN-network started off with 6 core-regions, covering all major climatic zones and including both islands and continental ecosystems1. In these 6 regions, it aimed to initiate and integrates surveys, monitoring, experimental research, and management of plant invasions into mountains1. The key goals of these endeavors where two-fold: to increase awareness about the growing importance of species expansion—both non-native and native—at high elevation and high latitude with global change3, and to offer possible solutions for conservation management and policy-makers.

Overview of the regions participating in MIRENs baseline screening and monitoring as of October 2018.

Since this first meeting in 2005, the network has steadily grown, and now it features over 20 mountain regions that participate in standardized baseline screening and monitoring, including the “T-transect” survey along mountain roads or trails and other experiments (see map). Through the years, MIREN has shown dedication to take on board scientists from developing countries 4,5 and has stated the case for transdisciplinary research that draws upon the expertise of social scientists, economists and bioengineers6. The network now even has its own mascot: Poa mireniana, a new grass species identified within long-term MIREN surveys in Kosciuszko National Park, Australia 7.

Poa mireniana, a new species of grass discovered during MIREN-fieldwork in the Australian Alps

We felt that after all these years of work, time was ripe to share our main conclusions with you. Mountain scientists, conservationists, mountain enthusiasts and policy-makers all over the world: read and take note, as in the following posts, we will summarize the fruits of 13 years of studying native and non-native species movement in the mountains. We will discuss patterns and processes of species movement and discuss the observed and predicted impacts of these travelling species on our mountain ecosystems. Ultimately, we hope to offer some useful suggestions for conservation and management.

The MIREN team at its latest meeting in 2017 in Centennial Valley, close to Yellowstone, USA.

A lot to tell, so stay tuned for the next episode!

References

  1. Dietz, H. et al. (2006). MIREN: A new research network concerned with plant invasion into mountain areas. Mountain Research and Development 26, 80-81.
  2. McDougall, K. et al. in Mountain Forum Bulletin. 23-25 (ICIMOD).
  3. Pauchard, A. et al. (2016). Non-native and native organisms moving into high elevation and high latitude ecosystems in an era of climate change: new challenges for ecology and conservation. Biological Invasions 18, 345-353.
  4. Pauchard, A. et al. (2009). Global networks: a reply to Khuroo et al. Frontiers in Ecology and the Environment 7, 518-518.
  5. Khuroo, A. A. et al. (2009). Plant invasions in montane ecosystems. Frontiers in Ecology and the Environment 7, 408-408.
  6. Kueffer, C. (2010). Transdisciplinary research is needed to predict plant invasions in an era of global change. Trends in ecology & evolution 25, 619-620.
  7. Walsh, N. G. & McDougall, K. L. (2018). A new species of PoaL.(Poaceae) from Kosciuszko National Park, New South Wales.
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SoilTemp meeting I

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SoilTemp symposium in the ‘Hof Van Liere’ of the University of Antwerp

The beginning of June saw a gathering of great minds in the city center of Antwerp. Thanks to support of the Research Foundation Flanders (FWO), we could invite over 30 ecologists and microclimate specialists to our beloved city, to have 3 days of inspiring discussions on our SoilTemp-initiative.

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In exciting anticipation of the meeting: programs and people, bring them together and  magic will happen

SoilTemp is a new global network, launched in autumn 2018, aiming to build a database of in-situ soil temperature measurements for use in ecology. A critical initiative, as has been shown that we are currently lacking an overview of the temperatures that truly matter for organisms, with many of our global climate models based on weather stations in controlled environments at more than a meter up in the air.

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Discussions over lunch

SoilTemp brings together all these scientists who are measuring the microclimate in the soil, and uses the combined power of global teamwork to once and for all answer the question how soil and air temperatures differ, and what those differences mean for our biodiversity.

To kick this initiative off officially, scientists from Flemish universities and far beyond put their heads together to decide how to answer the most crucial questions with the database at hand. In the inspiring setting of the ‘Hof van Liere’ at the University of Antwerp, plans were made for the future: papers to write, pitfalls to avoid, global collaborations to expand.

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(Part of) the international crowd propelling SoilTemp to the future. There is many more people to thank: those who already left, yet also especially also all data contributors who form the backbone of the network 

After a first afternoon with keynote lectures of experts from Antwerp to Australia, and two days of finetuning plans for the future, now it’s all hands on deck. The more than 15.000 years of temperature data from all over the world are being put in position, and first results are rolling in. Stay tuned for more, or – even better – join this amazing endeavour!

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Finetuning the SoilTemp-roadmap on the train to the meeting. May the rails be straight and the SoilTemp-train ride fast!

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Riding a camel over the morning sun at the central station in Antwerp

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Botanical beauty

A sunny spring day brought me to the botanical garden in Meise, close to Brussels. An amazing garden with picturesque views behind every corner.

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Spring in the botanical garden, with the castle of Bouchout in the background

A friend of mine makes it a point to stroll through the botanical garden of each place he visits; a philosophy I can definitely get behind. Botanical gardens not only are the ideal place to stroll, they also give a fantastic sample of biodiversity – of that particular place and well beyond.

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The greenhouses of the botanical garden in Meise, hosting hundreds of (sub)tropical species from across the world

Moreover, they provide a continuous reminder for the importance of botany; the study, and description of plant species and their diversity. This knowledge provides the critical base for all the research we are doing: you can’t study the effects of global change on biodiversity if you cannot identify that diversity first. And for that, our botanists and botanical gardens are of critical importance.

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So while it was only a short visit – no time to photograph all beautiful nature there was to see – it was a great reminder of its importance. Next time you visit one yourself, please keep this in mind while you take in its beauty.

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