The start of a new chapter (or many)

Autumn has arrived in Edinburgh – leaves are turning bright colours, students are returning to the campus, some chapters have ended, whilst others have only just began. It’ll be an exciting year for Team Shrub as new students join in and we put our curiosity and love for science into practice.

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Inspiring words as we go up the stairs every day

Team Shrub welcomes two new PhD students! After a field season in Northern Scotland and a field season in the Arctic, Gergana is back in Edinburgh to delve into the world of biodiversity change and its drivers. Her project aims to quantify the effects of land use change on global and local patterns of species richness, abundance and composition, and develop a computational framework to facilitate answering ecological questions using big data and global synthesis of long-term observations. In particular, she will investigate whether: 1) changes in species richness, abundance and composition can be attributed to land use change over recent decades, 2) land intensification and land abandonment are both causing species homogenisation, and 3) biodiversity change processes are more pronounced in areas of high land use change rates.

Mariana comes to us after spending almost four years working in Brussels at the International Union for Conservation of Nature (IUCN), where she worked on different biodiversity conservation-related projects, with her main focus being the assessment of species’ extinction risk as part of the IUCN Red List of Threatened Species. With her PhD project she aims to inform conservation action through science, specifically by modelling how plant species distributions will shift under climate change at two extreme biomes – the tundra and the savannah. In addition, she will research which traits make species more susceptible to population change and extinction, and whether the responses to climate change are generalizable or biome-specific.

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First day of being a PhD student for Mariana and Gergana!

We also have three new honours students joining Team Shrub!

Claudia spent her summer in the Peruvian mountains studying plant traits, which inspired her to think about how biodiversity and species traits vary not just across latitudes, but also with different altitudes. It’s very cool to see how species change from tropical to more Mediterranean-looking to tundra-type ones! Snow in the tropics is not something we often imagine, or see! Claudia will aim to answer the research question: “How do traits and biodiversity change across altitude in the tropics and in the Arctic tundra?”

Matt had an exciting summer being a field assistant first in Honduras, and then in Kluane.  He collected data on bird species along elevation gradients in both regions, and will be investigating how feeding guilds vary across the tundra and rainforest, and along the elevation gradients.

In his honours project, Sam will focus on quantifying the above-ground carbon stored in Arctic ecosystems, in particular on Qikiqtaruk-Herschel Island Territorial Park. Over the summer, we collected biomass samples for Sam from several different species, we dried them over the fire in the Community House, and now that we are back in Edinburgh, Sam can start with his carbon and nitrogen analyses!

We have also led the first Coding Club workshop – exciting to see Coding Club back for a second year of coding and statistics inspiration and knowledge sharing! With Coding Club, we want to create a friendly environment in which we can learn about quantitative analysis together. Coding Club is for everyone – all students and staff are welcome to come along and participate, regardless of their current R knowledge. We were thrilled to see people returning to our workshops, as well as many new faces – with new students come new ideas, new research projects and new data presents to open. Ah, imagine the graphs!

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The Coding Club cookies, featuring some pipes we piped!

Coding Club will soon celebrate its first birthday – in one year there have been many lines of code, the majority of them working, plus many workshops, posters and emails to spread the word. Every week there is a little pocket of R magic in our university building, though with over 50 people coming to our two workshops last week, the pocket doesn’t feel so little anymore! We have ambitious plans for developing Coding Club further, sharing what we have learned so far, and forming new collaborations. You can check out our tutorials on efficient data manipulation, data visualisation, mixed effects models and more on the Coding Club website. We are also very happy to have other people use our tutorials to deliver Coding Club workshops around the world, and would also love to have more people contribute online tutorials. If you are interested, you can get in touch with us at ourcodingclub (at) gmail.com.

A particularly great aspect of Coding Club’s first week back was that the workshops were lead by Sam and Claudia – two of Team Shrub’s new honours students. We hope to spread inspiration and motivation to learn through our workshops, and we were definitely inspired by Sam and Claudia’s great work! Coding can be scary and intimidating, but among the occasional fear and many R errors, we are glad that there is a place where we can brave the errors together and get better at finding the answers to our research questions.

And so begins a new chapter and a new year here at Edinburgh. We’re excited about what’s in store and looking forward to sharing our successes, setbacks, and many many shrubs with you over the next year.

Team Shrub Lab Meeting 2

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The end of a chapter (and the drafting of many)

Perhaps it was when I was waving to someone with a rusty hammer across a dusty runway, dragging a sledge full of dead leaves. Or perhaps it was when digging sunflower seeds out of the snow at 6am, while listening out for birdcalls and watching for bears. Or maybe when burying teabags on a wet mountainside, hoping they didn’t blow away in the wind. Whenever it was, I came to the realisation that this mad adventure called a PhD is soon to be over.

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After a total of six months, spread out over three different years, my time in the north is drawing to a close. The final measurements are taken, wet pages of my field book filled up with tiny scribbles. Mountains have been scaled and sampled, boots have been worn through, bags have been torn to tatters. Shrubs carried, cut, caressed, planted and replanted, grown and died and grown again. The last scraps of data have been pulled out of the ground and worked through the night that never grows dark.

In some ways this is a celebration. After three years of hard work, from my desk in Edinburgh to the snowy mountainsides of Canada, an end is in sight. The experiments have been successful, the science exciting, the chapters and manuscripts drafted. I can reclaim my summers: the friends’ weddings, the chaos of Edinburgh fringe, the lost time with my wife. This time, though it has been my shortest season yet, there is a real sense to homecoming. A departure with no promise of return. A clearly defined, bold and underlined, full stop.

Yet there is no doubt that I will miss this ridiculous and fantastic part of the world. The mountains that stretch from trees to sky, with the tundra almost (but not quite) out of reach. The endless expanse of…everything, as if the Yukon has simply never heard of the word ‘moderation’. The endless days, and occasionally dark nights lit up by the promise of the northern lights. I’ll even miss the mosquitoes, but not for very long. Most of all I’ll miss the people that have made me feel so welcome here, especially Sian and Lance at Icefield Discovery and the Yukon Parks Rangers on Qikiqtaruk.

And so I will sign off for this year, and leave you with the words of another that could say things far better than I ever could.

“I am one of you no longer; by the trails my feet have broken,
The dizzy peaks I’ve scaled, the camp-fire’s glow;
By the lonely seas I’ve sailed in — yea, the final word is spoken,
I am signed and sealed to nature. Be it so.”
Robert Service

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By Haydn

Qikiqtaruk perspectives by ranger Edward McLeod

Edward McLeod is a park ranger on Qikiqtaruk – Herschel Island from Aklavik, NWT.  Here he shares his perspectives on working as a park ranger and the collaboration between the rangers and researchers here on the island.

Working on the land

I started working as a Yukon Parks ranger on Qikiqtaruk – Herschel Island Territorial Park in 2008, so I guess next year I will have been on the island for 10 years. I always wanted a job out on the land, working outside, and I love being here. When I was younger, I used to spend my entire summers out in the bush – I love the bush life. I came to Qikiqtaruk and Shingle Point many times as a kid – I grew up here, and it was wonderful to be able to play around on the coast and see all the animals, as well as learn about hunting and fishing. I saw what was probably the first cruise ship coming to Qikiqtaruk.

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Coastal erosion near Pauline Cove this summer. Check out http://www.cbc.ca/news/canada/north/yukon-herschel-island-erosion-1.4253948 for the CBC article about it!

I remember there used to be more ground than there is now – coastal erosion has taken away big chunks of land, and beaches have appeared and disappeared through the years. Travelling the coast has always been a significant part of my life, and a key element of travelling is being able to adapt to change. There would be three-four boats travelling together, and sometimes we would get stuck in places for weeks – we have to make sure we have enough food, and know how to use landmarks to navigate once it is safe to move on. I’ve always heard you used to be able to predict the weather by looking at the clouds, but nowadays it changes so quickly, we always have to be prepared for everything. But, I’ve never gotten really lost on Qikiqtaruk, or in the Mackenzie Delta, I know these places like the back of my hand. Still, once I got caught in a storm and I had to sleep outside between my snowmobile and toboggan, with everything I carried wrapped in a tarp. It was a good thing I had a cozy muskox hind to sleep on to keep me warm. Before I made the shelter, I was going in circles for hours, and thankfully I was carrying a spot device, so my brother and two uncles noticed I was going in circles, and came and brought me back home to Aklavik before the storm got worse.

A ranger’s skillset

To be a ranger, you need traditional bush skills – hauling water and wood, making a fire, travelling with a snowmobile. If something goes wrong, you have to know how to take care of it without much help from the outside world. Having an education is also important, as we keep records including a daily journal, wildlife records and fill in data collection sheets for the Ecological Monitoring Programme. A good sense of humour is also key, especially when you spend such a big portion of your time with just one other person – the other ranger with whom you share your shift. We have to make our own life here on the island – you have to be easy going and go with what life throws at you.

During the winter months, I teach traditional bush skills in my community and beyond. There’s the Elders and Youth Programme as well, but it’s not enough for people simply to know about these opportunities – they have to take them up. My daughter is gaining bush skills, and I hope she keeps developing them. It’s important that youth are taught traditional bush skills.  Perhaps my daughter will follow in my footsteps and be a ranger out here on the island one day herself!

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Monitoring plant phenology plots on Qikiqtaruk

Ecological Monitoring Programme on Qikiqtaruk – Herschel Island

I was excited to find out that ecological monitoring is part of my job as a ranger, and to learn more about the plants and animals on Qikiqtaruk! But there are so many other ranger duties as well, so we have to learn how to balance everything. I started with surveying the plant plots, we now call the area Phenology Ridge, because there are three transects, one each for arctic willow, mountain avens and cottongrass.  This is where we record plant phenology – the timing of certain life events like the first opening of the leaves and flowers, the first yellowing leaves. I was surprised to find out how long some of this monitoring takes – for example during peak season we go to the cottongrass plots and count all the flowers, as well as measure the width of the tussocks, the ten largest and the ten smallest leaves. This monitoring has been taking place for 18 years, making it one of the longest running phenology records across the Arctic.

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Muskox walking along the beach

We also conduct permafrost measurements, as well as bird surveys and wildlife monitoring, which came to me naturally. We record the population numbers, behaviour and travelling patterns of the different wildlife species present on the island. Qikiqtaruk has the second largest black guillemot colony in the Western Arctic, and we collaborate with Cameron Eckert, Yukon Parks Biologist, to count the eggs, chicks and adults. We also ID the birds that are ringed and recaptured, which gives us an insight into survival rates and population changes of these birds.

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Black guillemot (Cepphus grylle) swimming near the Mission House

Contributions of the Ecological Monitoring Programme

I really enjoy working in close collaboration with the researchers and I especially value knowing why we are collecting the data and what is done with them. My first job on Qikiqtaruk was as a research assistant on the ArcticWOLVES project during the International Polar Year. I know that participating in research and understanding its findings can help motivate people to finish school and become more qualified for jobs. When I go back to my community, people ask me what the researchers are doing on Qikiqtaruk – that’s why I appreciate everything I have learned from our collaboration, because I get to pass on the knowledge.

I get updates from the researchers, including Team Shrub and the crew from the Alfred Wegener Institute, through presentations, reports and one to one chats. I also like following Team Shrub and the Permafrost Researchers through social media, such as Facebook, which keeps me up to date even during the winter months when we are all off the island. I think social media really helps with communicating research findings, but people also need to request the information and say what format is most convenient for them – not everyone in the communities use social media that much, so communicating science in different ways is important.

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A mass of drift ice with about 300 Ringed Seals and a few Bearded Seals brought this Polar Bear to Qikiqtaruk on 13 June 2015. Photo by C. Eckert

I love the collaboration between the rangers and researchers and I am excited to see how it develops in the future. Perhaps we can do more to connect researchers with people travelling in winter and spring.  Usually researchers cannot be here during that time, so people travelling like me could collect valuable data that would not be available otherwise. It might also be worthwhile to extend the range of the surveys conducted in this region to include things like monitoring berries for example, which are a valuable resource to the Inuvialuit. Qikiqtaruk is definitely the right place for ecological monitoring and I hope we can continue to build on the collaboration between the park rangers and scientists and better involve the people of Aklavik.

By Edward McLeod

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You can read another guest blog post by Yukon Parks Ranger Ricky Joe here – Changes on Qikiqtaruk: Perspectives by ranger Ricky Joe.

The tundra is cold

August, 2017

Up in the Ruby Range, beyond the treeline and where even the shrubby birches and rugged willows struggle to grow, it is snowing. The clouds are low, unfurling over the mountaintops, and thick snow is falling in fat flakes that rapidly turn the rocky ground white. Everywhere around the peaks have disappeared into a milky haze, earth and sky no longer distinguishable. It is a beautiful sight. Or at least, it would be if we didn’t still have eight hours of fieldwork to do.

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The tundra is cold. Perhaps that is stating the obvious just a little bit, but after two weeks working in blazing sunshine and working on our tan lines, it is helpful (though not at all pleasant) to be reminded of the fact. Right now Team Kluane is camped out in the Ruby Range to the east of Kluane Lake, and it is very cold indeed. We have to brush the snow off the tent to open it up, and leave a deep trail of footprints as we walk to ‘the pod’, the white (and growing ever whiter) dome of comfort left over from when Pika Camp was a bustling hubbub of research activity. Even as the kettle whistles and fills the room with a column of steam (or is that just our breath?) we realise that our research for the day is in jeopardy as the seeds Matt and Cameron have to find for Anna Hargreaves’ herbivory experiment are soon to be completely lost under the blizzard.

Up here there is little time to rest, and when you do it gets even colder. The solution is simply to get on with it. We warm up as the day does, and the snow gradually recedes from the mountainside as the sun climbs just a little higher. Soon the leaves emerge once more and it is simply chilly. I even take off my hat. Briefly.

There is respite in the afternoon as we rest against the pod wall watching the cloud billow through the passes and listen out for snowy owls on the hillside. But all too soon the evening creeps up – not quite day but not quite dark. We retreat inside where the wind can’t reach us and mugs of hot chocolate await.

When we wake the next morning things are looking up. Peeking out of the folds in the sleeping bag there seems to be no snow on the roof of the tent. Nor is the wind that somehow pierces our many layers blowing. In fact, the tent doesn’t seem to be moving at all. As we open the tent, a snap and crackle of crystals soon tell us why – it has frozen solid. As I said, the tundra is cold.

By Haydn

Qikiqtaruk Book Club Part IV: Theory and high-level processes in the Arctic

August, 2017

Page after page, we have been pondering patterns and processes in community ecology under the sounds of gusting winds and heavy rain. From one storm to the next, when our field days were cut short, we could sit by the fire in the Community Building (the oldest building in the Yukon) and delve in deeper into Mark Vellend’s “The Theory of Ecological Communities”.

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The Pauline Cove settlement with the Community Building reflecting in the water of the Arctic Ocean late at night in the transition from sunset to sunrise.

We talked about selection and the many selection-focused hypotheses of shaping and maintaining ecological communities, and singled out the ones most relevant to the tundra and our work. We then considered speciation, dispersal and drift, which still influence communities on the island, though they might not be as important relative to selection.

We have now wrapped up our field season and returned to Vancouver. Along with mailing away samples and inventorising equipment, we have also turned the final pages of Mark’s book. Here, we will share our final book club thoughts, with a particular focus on the theories, which relate most to our work in the tundra.

We see our study of vegetation change in the Arctic as being detective work – you figure out a question, gather evidence, open the data present, and interpret what it means. For us, explanation and prediction in ecology go hand in hand, and we aim to do both – you can’t make predictions without knowing how your system works. Although theory development is perhaps not the main motivation of our work, we don’t shy away from reading about different theories and seeing how they can inform our research. In fact, we go as far as playing “Guess the ecological theory” at breakfast – a stimulating start to the day!

We think of theory as a way to simplify complex ecological phenomena in order to make them generally applicable. The same rules don’t apply everywhere, though, and our goal is to find which rules are relevant for the tundra biome, not necessarily to extrapolate across the entire world. The same global change drivers have different impacts across the world’s biomes, making the drawing of universal conclusions even harder. Nevertheless, sometimes theory works, and here, we will present the Arctic edition of when that happens.

Table 1. Theories we consider relevant to tundra vegetation change and our work.

Theory Links to the tundra biome and our work
The competitive exclusion principle (Gause 1934) and R* theory (Tilman 1982) Competitive exclusion likely exists within the tundra biome with species competing for the limited resources of the tundra environment. Species have specific adaptations from forming tussocks to outcompete other species and form their own microclimate to having evergreen leaves allowing them to start photosynthesis as soon as the snow melts in spring. Each plant species has its own combination of traits to deal with the short growing seasons of the Arctic and those different traits likely promote coexistence. Each species likely does have its single resource for which it can survive at the lowest equilibrium level (R*), but figuring out which species are best adapted to exploiting which resource is a bit of a challenge.
Temporal and spatial storage effects (Chesson 2000b) – Selection spatially variable and negatively frequency dependent The spatial and temporal storage effect is likely at play in a major way the Arctic.  Species are specifically adapted to the harsh environmental conditions and can store resources for reproduction or growth during hard times that they can then use when conditions allow.  Some species are adapted to thriving under snow patches, others to coping with drought conditions, others to dealing with flooding and soil saturation yet all can cope with the cold.  These different sorts of adaptation can promote species coexistence and diversity across the tundra landscape.
Enemy-mediated coexistence (Holt et al. 1994) Enemies do exist in the tundra.  We have been monitoring herbivory sign for the past four years on the island and have found the rates of herbivory to be relatively low.  But the herbivores are out there and are a selective pressure in the landscape.  From leaf herbivores from caterpillars to lemmings to caribou, seed and fruit herbivores from fly larvae to humans, herbivores can take a bite out of the carefully allocated resources that tundra plants have invested in growth and reproduction. Likely herbivory is a bigger deal in places like the European Arctic or Northern Quebec where large herds of reindeer or caribou roam around munching on shrubs.  The main Porcupine Caribou heard doesn’t make it out to Qikiqtaruk and large animal herbivory rates are lower. How important is herbivory at sites across the Arctic?  Well that is something that the Herbivory Network is trying to figure out.
Priority effects (reviewed in Fukami 2010) Do initial colonists get an advantage in the tundra? Perhaps this is particularly relevant in the Herschel vegetation type where disturbance rates are lower and the species that invade first might be able to persist longer.
Multiple stable equilibria (reviewed in Scheffer 2009) Are there multiple stable states in the tundra?  This theory is probably quite relevant for the transition from sedge- or herb- to shrub-dominated tundra as tundra shrubification occurs as can be seen in repeat photographs on Qikiqtaruk.
Succession theory (Pickett et al. 1987) Succession is at play across the tundra biome where disturbance is likely the major factor shaping ecological communities.
Intermediate disturbance theory (Grime 1973, Connell 1978) The intermediate disturbance theory can be tested with our data – check out our plot of bare ground (a proxy for cryoturbation, a type of disturbance ) vs species richness at the plot level in 2017 (Figure 1).  Depending on how you look at it we either do or don’t see the expected hump-shaped relationship of species richness in relation to disturbance – in our case cryoturbation.
Metacommunities: species sorting (Leibold et al. 2004) – spatially variable selection, different species are at an advantage under different environmental conditions Species sorting and spatially variable selection due to different environmental conditions might explain the different plant communities that we see on the island. See the Book Club II blog post for more thoughts on selection.
The species pool hypothesis (Taylor et al. 1990) Different species pools sizes on the island or at a larger spatial scale within the tundra biome likely do influence local richness.  Through the ArcFunc project we can test this theory further. You can also check out our species-accumulation curves (Figure 2).
Island biogeography (MacArthur and Wilson 1967) Island Biogeography can be tested using breakfast cereal, so it probably is at play in the tundra biome with distance from glacial refugia being a key factor.  Isolation could explain the species richness and ecological communities on Qikiqtaruk relative to the adjacent mainland.  And certainly, island isolation creates barriers limiting the expansion of tall shrub species within the Arctic at the biome scale.

 

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Figure 1. Species-accumulation curves for the Herschel and Komakuk vegetation types. Distance refers to the distance away from our community composition plots. In Herschel, most of the species are found close to the plots, and the relationship quickly saturates, whereas in Komakuk, as we move further away from the plots, we continue to find new species.

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Figure 2. Species richness and bareground cover in the Herschel and Komakuk vegetation types of Qikiqtaruk-Herschel Island. Points represent mean species richness for 12 plots monitored from 1999 to 2017 ± standard deviation. Darker colours represent overlapping points. The Herschel vegetation type has very little bare ground (apart from that one plot!), whereas in Komakuk, bare ground is a defining characteristic of the vegetation type.

Our work on tundra vegetation change spans across several different levels of analysis, which together will hopefully shed light on how communities in the Arctic are responding to global change drivers. We are monitoring particular individuals for phenology, and surveying 12 x 1 m2 community composition plots on one Arctic island, four pairs of 100 m2 plots for our drone surveys (in the Herschel and Komakuk communities), large-extent sites part of the HiLDEN network, and finally the tundra biome, which we can study as a whole thanks to the ITEX and ShrubHub networks. We are investigating how community composition is changing by studying species and traits in collaboration with the Tundra Trait Team. Along the way, we often come across what Mark calls the “three-box problem” – there will probably always be silent or ‘lurking’ variables we fail to account for, and drawing the line between causation and correlation is rarely easy.

Do we observe different species in a particular place because the environment is different, or is the environment different, because the species are different? What is the trade-off between diversity and invasibility? This year, we recorded the same number of species (32) in both the Herschel and Komakuk plots, but the Komakuk plots are probably more susceptible to invasions, since with more bare ground patches, there is more room for new species to germinate and establish. Alopecurus alpinus has already taken advantage of this opportunity, and more species might follow soon, as from our species pool survey, we found that there are many more species found close by to our plots in both the Komakuk and Herschel vegetation types.

Having read “The Theory of Ecological communities”, spent many hours out in the field and conducted preliminary analyses of our collected data, we think that species sorting  and the metacommunity framework, applies best to Qikiqtaruk-Herschel Island. Here, we can observe very strong spatially variable selection, leading to the establishment and presence of distinct vegetation communities. Although of relatively less importance, patch dynamics could also be at play – spatial and temporal variation in selection could cause local extinction, and dispersal could lead to (re)colonisation of certain species. Such is the case with the grass species Alopecurus alpinus that colonised our Komakuk community composition plots between 2004 and 2009. The neutral framework, on the other hand, has little application in the Arctic context, because drift is not a dominant force shaping ecological communities here. Mass effects, whereby selection is spatially variable and not strong enough to prevent immigrants from establishing sink populations, is also likely of little relevance to the tundra, since selection here is very strong, potentially preventing new immigrants from establishing in the first place.

The Theory of Ecological Communities

Isla’s copy of The Theory of Ecological Communities that looks like it has been eaten by a polar bear! But it was actually partially eaten by a dog. Clearly a book you can really chew on – some ecological theory you can bite into… photo credit to Cameron who is reading the book next!

We thoroughly enjoyed reading “The Theory of Ecological Communities” whilst on fieldwork at our remote field site in the Canadian Arctic. There is particular charm in reading about a certain ecological process, be it high- or low-level, and then observing it in action moments later in the field. We look forward to continued discussions of the synthesis of ecological theory, but definitely agree with Mark that four high-level processes do shape community composition – selection, speciation, dispersal and drift.

By Gergana and Isla

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This blog post was written on Qikiqtaruk-Herschel Island in the Western Canadian Arctic as part of Team Shrub’s island book club, aiming to read and discuss Mark Vellend’s 2016 book “The Theory of Ecological Communities” while we are out in the field, right next to the communities we study.  Team Shrub are a group of plant ecologists who often work in high-latitude tundra ecosystems on topics in community ecology.

The team’s book club discussions are summarised in four blog posts:

 

Qikiqtaruk Book Club Part III: Speciation, dispersal and drift in the Arctic

August, 2017

In the book ‘The Theory of Ecological Communities’ by Mark Vellend speciation is one of the four high-level processes explaining local community patterns and dynamics.  Mark discusses the influence of regional species pools and speciation rates on local diversity.  In many temperate and tropical locations speciation has happened in situ over evolutionary timescales, but the Arctic is different.  Here, long-term dynamics are controlled by glacial and inter-glacial cycles.  More than twenty thousand years ago at our field site Qikiqtaruk – Herschel Island, there probably was no island at all and instead just the terminus of the Laurentide ice sheet.

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Pauline Cove surrounded by ice at the start of the summer

What determines regional richness today at least for plants in much of the Arctic is the distance to glacial refugia and time since de-glaciation.  Here on Qikiqtaruk, we are located pretty much right at the edge of Beringia – the unglaciated region in the Yukon, Alaska and Eastern Siberia during the last ice age. We are also close to one of the northern most extents of the treeline around the circumpolar Arctic, such that the boreal forest species pool is only about 100 km away.  This means that potentially species diversity will be higher here than in other similar environmental conditions in other parts of the Arctic.

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The colourful variety of flowers on Qikiqtaruk-Herschel Island in spring is a sight to be seen.

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Figure 1. A phylogenetic tree of many of the plant species on Qikiqtaruk-Herschel Island. Yellow are grass species, purple are forbs, red are deciduous shrubs, and green are evergreen shrubs. The tundra is more diverse than you might think!

If we are thinking about the diversity of other species, most of the birds are migratory here and spend their winters thousands of kilometers farther south, some as far south as the neotropics or even the southern hemisphere.  What determines local avian diversity is therefore migratory dynamics.  Presumably Arctic bird species did not speciate here in the Arctic, but in their winter ranges and then over time explored further and further northward breeding grounds.

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A sandhill crane (Grus canadensis) egg we found just laying on the tundra!

We have enjoyed tag team birding with Cameron Eckert, Yukon Parks biologist, and hearing about or seeing the regular rare sightings of birds outside of their normal ranges from the Calliope hummingbird, tufted puffin, short-tailed shearwater to the gyrfalcon that we documented ourselves as it came through camp.  The bird species pool is a dynamic one, with more and more sightings of southern birds blowing up on the winds of storms.  It is good to reflect on communities of species that are far more mobile than the perennial tundra plants that we study.

At the end of August, we conducted an additional protocol as a part of the International Tundra Experiment to document the size of the tundra plant species pool around our long-term monitoring plots.  By tromping around in concentric circles we were able to identify 36 additional species within 100 m of our plots.  These species could be invading into the ecological communities in the future.  The closest observed new species were Parrya naudicaulis, a pretty brassica a mere 2 m away from the ‘Herschel’ vegetation plots and a Papaver radicatum, a lovely bright yellow poppy about 5 m away from the Komakuk vegetation plots.

 

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Figure 1. Species-accumulation curves for the Herschel and Komakuk vegetation types. Distance refers to the distance away from our community composition plots. In Herschel, most of the species are found close to the plots, and the relationship quickly saturates, whereas in Komakuk, as we move further away from the plots, we continue to find new species.

It is very likely that new species will be entering into the plots in the future, but perhaps also likely that other rare species within the plots will disappear over time – representing the dynamics between dispersal, ecological drift and local extinction.  But overall will these plots become more diverse as the growing seasons continue to lengthen and the permafrost-related cryoturbation disturbances decrease?  With one major species invasion in the first 18 years of the ecological monitoring programme, perhaps increasing diversity is the prediction that I would make for these plant communities.

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Alopecurus alpinus (foxtail grass)

Very slowly over time in these perennial plant communities, evolutionary selection is occurring and perhaps new species are forming in situ adapting to the changing environmental conditions.  One of the goals of Team Shrub’s research is to identify how much local adaptation occurs between populations of shrub species along large elevational gradients and to test whether Arctic shrubs have genetically limited growth rates and canopy heights relative to the same species growing further south.  Perhaps we are observing speciation in action – though we probably won’t be around to see the outcome of natural selection in the Arctic, unless we will???

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Sydneyi qikiqtarensis – a lovely herbarium specimen prepared during the Elders and Youth Programme 2017!

By Isla and Gergana

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This blog post was written on Qikiqtaruk-Herschel Island in the Western Canadian Arctic as part of Team Shrub’s island book club, aiming to read and discuss Mark Vellend’s 2016 book “The Theory of Ecological Communities” while we are out in the field, right next to the communities we study.  Team Shrub are a group of plant ecologists who often work in high-latitude tundra ecosystems on topics in community ecology.

The team’s book club discussions are summarised in four blog posts:

 

Our final days on Qikiqtaruk for 2017

Our Arctic field seasons are both long with the passing of 24 hour days and hard work out in the field and incredibly short.  Now that the field season is over and summer has ended in the Arctic, we can reflect on our final days on the island and what we accomplished during the field season of 2017.

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A lovely meal in the sunshine on the last day before the rain and wind came!

When you are in the swing of fieldwork, you are in a routine of “early” mornings and very late nights and long days out on the tundra.  On Herschel time, you get up at the crack of 10 am and then work out on the field sometimes as late as midnight or later with bedtime at around 2 to 4 am.  After each long day in the field, you colour in a few more boxes on the fieldwork plan of tasks accomplished, but there is so much left to do that you wonder if we will get it all done.

On Qikiqtaruk you are always at the mercy of the weather and no time more so than at the end of the season.  As the tundra starts to turn yellow and brown, the temperatures start to decrease and the fog starts to roll in grounding drone flights.

Storms are common in August and this August was no exception with a three-day storm overlapping with the date our charter flight was supposed to pick us up off of the island.  That meant a day of being weathered in, but also a chance to do more last-minute data collection in the driving winds and rain.  This year’s common garden samples might have been collected in pretty horrible weather, but here’s hoping those willows thrive in their new warmer home in the Southern Yukon.

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Wet days out in the field. We were not wearing crocs out there, but Gergana’s wellies were too wet to spend any more time with them on! Photo by C. Eckert

This year there were some end of field season weather surprises for us.  Unlike last year when the fog grounded our drone flights for more than a week.  This year there were a few glorious days allowing us to get back to Slumps D and ABC to quantify permafrost thaw across the 2017 growing season.  We were also able to complete a final round of multispectral flights over all of our tundra plots as the tundra was turning from green to brown and the plant phenology records indicated the yellowing of leaves and release of seeds.  On the final glorious day before the storm, Andy and Will made it out to fly large extent flights of the Ice Creek watershed, allowing us to put our higher resolution data into a larger landscape context.

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Ice Creek from above with Cameron Eckert (bottom right) and the “Bottomless Pool of Eternity” (top left) visible in the frame.

Just hours before flying off the island, we even managed to achieve one of the most elusive goals of the field season. It still feels slightly unreal, but after many attempts, involving finding different types of batteries, cables, Allen keys, screwdrivers, and building shelters to keep the rain out when taking the computer out into the field, we are finally happy to report success. We have downloaded all the data from our HOBO temperature data loggers, put in new batteries and restarted the data logging for the winter. These might all seem like simple tasks, but really, when you are out in the tundra, so many elements have to come together in order to achieve your goals!

Just when we had one HOBO sorted and ready to tackle the second one, we found out it requires entirely different tools to open it and cables to download the data. Because of the pouring rain, the process had a distinct Russian doll flair to it – a laptop inside a bin bag inside an emergency shelter inside a tarp.

On the morning of our last day, though, everything came together.  Beautiful belugas accompanied us on our beach walk towards the data loggers on Collinson Head.  We had all the tools we required (well almost), we even managed to improvise a radiation shield out of wooden skewers and medical tape to fix the broken one on that pole.  And once we removed all the screws without dropping them in the pond below the logger box and plugged in the cable without getting it wet, the data were on our laptop in minutes! Yukon Parks conservation scientist Cameron Eckert was there to document the big moment – thankfully we are better at handling data loggers than high fives! It is a great feeling to leave your field site knowing that you have accomplished all of your fieldwork goals.

Though two months in the Arctic can seem like a long time when the data collection is going on, it is also a very short time.  The end of the field season is when you begin to realize that your time on the island is coming to a close.  You have your last walks across the tundra, last dinners with the community of people on the island and the last dips in the Arctic Ocean.  This field season marks the end of the three-year ShrubTundra project.  We have lots of data analysis and writing ahead, but no more data collection on this specific project.  Sigh.  Though the science never really ends!

We have learned an incredible amount over the past three years and it will be great to see all of that work come together, but it also brings us to the question of what research questions should we be tackling next.  The work of a scientist is never done, as soon as you learn one thing, you are already thinking about the next question that you want to answer.  Perhaps, through the HiLDEN network or other opportunities we will be able to explore whether some of the things that we have discovered at Qikiqtaruk-Herschel Island apply across other Arctic tundra locations.

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Removing drone markers leaves a literal mark on the tundra of our 3-year research on the island that will quickly grow over.

Here are some of the preliminary research findings of the Shrub Tundra project research on Qikiqtaruk-Herschel Island:

  1. Plant phenology including the leaf out, flowering and to a certain extent leaf senescence is occurring earlier on Qikiqtaruk over the past 18 years as snow melts and sea ice retreats earlier (Qikiqtaruk Ecological Monitoring Team, in prep., Assmann et al. in prep., Lehtonen Ecology Honours Dissertation 2015).
  2. Plant biomass and height is increasing across the patches of monitored tundra and certain plant species are becoming more abundant including Eriophorum vaginatum (cottongrass) and Salix pulchra (diamond leaf willow), while other plants are found in the monitoring plots that weren’t there 18 years ago such as the grass species Alopecurus alpinus (Qikiqtaruk Ecological Monitoring Team, in prep.).
  3. Although plant heights are increasing community-level leaf traits such as the specific area of the leaves is not occurring very rapidly at Qikiqtaruk or other tundra sites (Bjorkman et al. in prep., Lowe Ecology Honours Dissertation 2015).
  4. Tundra traits differ from other of the worlds biomes and it is the traits of plants that link vegetation change to changes in decomposition and carbon cycling (Thomas et al. in prep.).  That is why understanding how rapidly plant traits are change is key to understanding the implications of future tundra vegetation change.
  5. Qikiqtaruk willows can grow in warmer environments 1000 km to the south, but local adaptation to Arctic light conditions means that they are not growing as fast as their southern alpine counterparts in our common garden experiment that are really able to respond to the warmer growing conditions at the lower elevation down in the boreal forest.
  6. Climate is not always the factor explaining the variation in growth of shrub species from year to year on Qikiqtaruk, indicating that other factors such as deepening active layers and thawing permafrost releasing nutrients might be a driver of vegetation change (Qikiqtaruk Ecological Monitoring Team, Boyle Ecology Honours Dissertation 2017, Angers-Blondin et al. in prep.).
  7. Decomposition rates differ among microclimates, and soil moisture is just as important as temperature in explaining decomposition rates, but these differences are small compared to the differences between different types of plant litters (Walker Ecology Honours Dissertation 2017, Thomas et al. in prep.). As vegetation changes, so too might tundra decomposition rates.
  8. Analysis of drone imagery and 3D models indicates that tundra greenness is strongly related to topography and wetness of the landscape, but that this relationship depends on the scale of measurement. As permafrost thaws, this could lead to increased moisture where ice wedges are thawing and increased tundra plant productivity (Kennard Geography Honours Dissertation 2017, Assmann et al. in prep.).
  9. Rates of permafrost thaw and coastal erosion can be rapid and are associated with moisture in the landscape, with sometimes faster thaw rates in areas with water tracks or streams than in adjacent drier tundra (CBC article on high coastal erosion rates, Cunliffe et al. in prep.).

But these are just some of the results so far.  Once we have analysed this year’s data in association with the data that we have collected over the past three years, we will really be able to put the story together of how vegetation is changing on this island in response to climate and environmental change and what that might mean for the future of this tundra environment.

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A final feast on the island before we departed.

After we made it off of the island after a one-day weather delay and a second day of ‘will we or won’t we fly’, we managed to make it back to the busy and bustling town of Inuvik where we had a few days of packing and inventorising.  After getting all of our stuff organised and shipped back to Edinburgh or put into storage we had a chance to explore the MacKenzie Delta and town of Inuvik.  Then we travelled down to Whitehorse and out to Kluane to bring this year’s common garden samples to their new boreal forest home.

Our arrival in Kluane meant the first reunion of the entire TeamShrub field crew for the field season of 2017.  Finally, Team Drone could meet up with Team Kluane and share stories of our very different field adventures in the Canadian North.  The reunion was celebrated with a party involving one last feast, music and even a magnificent show of the northern lights from green to pink rippling and dancing across the skies overhead.  And with the final planting of willows in the common garden and a bit more storage and inventorising, our fieldwork was complete.  Time for Team Shrub to have one (or several) last exploding high fives and to depart southwards and back to our other non-fieldwork lives.

Thanks Team Shrub for an amazing and incredibly productive field season!  I can’t wait to see all of the data presents that will be revealed over the coming winter.

By Isla and Gergana

The Scottish Feast – 2017 edition

A community of people coming together, a beautiful outdoor setting, delicious food and fun chatter late into the night – all of those and more made for a particularly special Scottish Feast this year! The feast included several island firsts – the first time we had real haggis thanks to the Grabowskis from Whitehorse, the first time the feast was outside thanks to the lovely sunny weather, and some pretty innovative hoola hoop action, when we kicked a ball around whilst hoola hooping!

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Lovely weather allowed us to have the first-ever outdoors Scottish Feast! Not something you’d do in Edinburgh.

Though planned at the last minute and without much time to prepare, the feast definitely did not disappoint, and it’s always impressive how events like this come together – everyone contributes, and then we get to share the festive atmosphere that follows! The feast brought together Team Drone, the AWI crew, Yukon Parks rangers Edward and Ricky, as well as the Yukon Government Heritage Crew – we come from all over Canada and the world, but this summer, we got to share the beauty and weather unpredictability and occasional challenges of Qikiqtaruk together.

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The Qikiqtaruk Scottish Feast 2017 – a table of plenty under the midnight sun.

First came the haggis, and then the speeches! Isla piped in the haggis, which Ricky then cut with the ulu –a traditional Inuvialuit knife. The haggis was a success – for some of us, it was the first time trying haggis, for those of us living in Edinburgh, it was a nice reminder of home. Then came the speeches and recitations by all members of the table. Being allocated a speech to give on the spot was a surprise for those of us that hadn’t been to a Scottish Feast before, but everyone did a great job, and there were many laughs, thanks to jokes, interpretive dancing and poems!

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Isla piping out the haggis to the sound of the tables a capella bagpipes.

We also gave the rangers this year’s Team Shrub t-shirts, and for the first time ever, the Team Shrub hats or toques – to use the Canadian word for them! This year’s design was mostly generated by code in R – in particular our map illustrating where we all are from, and which field sites we are going to – Qikiqtaruk or Kluane. The front of the t-shirt features “Team Shrub” written in all the languages we speak on the team – English, French, German, Inuvailuktun, Bulgarian, Spanish, Finnish, Danish, etc. Sadly we ran out of time to add Polish, spoken by our most recent addition to the team, Informatics Master’s student Karol! Next t-shirt! The Team Shrub hats are nice and warm, though for next year we might explore hats that have an insect-repellent coating!

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Some say they inspired a nation – the mosquitoes that is not the hats!

We loved hearing about the finds of paleontologist Liz, and we couldn’t resist showing her some of the bones we’ve found – one find was particularly exciting, though we didn’t quite realise it at the time. Isla picked up a bone from what she thoughts was the leg of caribou from Slump D as we were on the run from the epic storm – it was a very big bone fragment, though it didn’t really give off a mammoth vibe, which is what we were hoping to find! Turns out the bone is from a Pleistocene horse, and more interestingly, the bone is, we think, only the second bone found on Qikiqtaruk that was found inland and not on the beach!  It has now been documented and shipped to Whitehorse for radio carbon dating… One day we will find out how old it really is, telling us what animals were living on this island, back at the end of the last ice age perhaps.

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Hoola hooping after the feast

This year’s sporty activity was also inspired by Liz who had made two hoola hoops to bring to the island – most of us had a go at the hoola hoops, and Gergana still has bruises from some enthusiastic knee hoola hooping. We then hung out by the fire, as the sun was first setting and then rising – bathing the island in a beautiful golden light – a lovely evening to spend together in appreciation of our time on Qikiqtaruk!

By Gergana

New adventures in birding: Part 2 – Why birding isn’t so bad after all.

I recently wrote – or perhaps you could say vented – about our recent forays into birding. With an additional morning under my belt, I’ve had a bit of time to reflect. Perhaps birds aren’t so bad after all.

  1. Birding is cool.

By cool, I mean cold. Birding is still definitely not trendy cool, but right now I’d happily embrace an icepack wearing socks and sandals. Kluane is melting under a heat wave, and in the full blast of the sun we are getting baked from the lakeside to the alpine. The bird surveys, and the early mornings that come with them, are a welcome relief.

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Birding in the wee hours of the morning means peace and fresh air

  1. Birding is peaceful

Our surveys last 30 minutes at each site. Here in my field assistant role, my responsibility is simply to record any new bird calls we hear. As Matt’s identification skills improve, there is less and less for me to do, and more and more time for me to do what I like best – perfecting the art of the tundra nap. It is incredibly peaceful drifting off to sleep to the rustle of the willows, the distant wash of waves on the lake shore, the buzz of pollinators, the soft tweet of an unknown bird call….oh wait! Damn, where is that recorder!!

  1. Birding is exciting

There is a certain thrill to coming across a new species, or getting that perfect photo you’ve been waiting all morning for. Sometimes the surprises are small – a colourful bird settling in the shrub above your head. But as Cameron found with the hummingbird on Qikiqtaruk, you never know what you may see!

  1. Birding is interesting

For all their skittishness, and the whole moving around thing, things that aren’t plants can sometimes be interesting. Even though I’ve walked up and down the Plateau many times now, seeing the drop off in bird diversity with temperature – in the data and with my own eyes and ears – is neat, and a nice little test of theory.

  1. Birding is beautiful

Once again, no explanation needed.

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By Haydn

Qikiqtaruk Book Club part II: Selection in the Arctic

July, 2017

A variety of different evolutionary strategies promotes species coexistence in the Arctic – there is not one way to handle the short growing seasons and cold. This year we ran a new protocol, part of the ITEX network, which involves surveying the species pool around our community composition plots. We thought the protocol would take us a couple of hours, but little did we know that six hours in we would still be walking in concentric circles around our plots, identifying species after species. We were surprised by how many vascular plant species we found (55 near the plots in the Herschel vegetation type and 66 near the plots in the Komakuk vegetation type) in our two focal ecological communities, and we have been pondering what processes are shaping and maintaining diversity here on Qikiqtaruk ever since.

In “The Theory of Ecological Communities”, Mark Vellend singles out four high-level processes, which shape ecological communities – selection, dispersal, drift, and speciation. The relative importance of each of the four processes varies among biomes – for example, drift might strongly influence communities in tropical areas, whereas environmental filtering, a type of selection, might have a bigger role in cold or arid places where conditions are harsher and resources are limited. Dispersal does have a role on Qikiqtaruk, as for example the grass species Alopecurus alpinus is a recent arrival to our Komakuk monitoring plots between 2004 and 2009, and has been increasing in abundance ever since. Many tundra plants have small seeds and are adapted for long-distance wind or animal dispersal such as the feathery seeds Dryas integrifolia (mountain avens), the fluffy seeds of Eriophorum vaginatum (cottongrass), or the tiny seeds and fluff of willows. Nevertheless, out of the four high-level processes shaping ecological communities, selection seems to be the dominant force here in the Canadian Arctic.

One of the factors discussed by Vellend (2016) influencing community composition is negative frequency-dependent selection.  That is a relative advantage for a species when rare relative to other species, because of inter-specific competition, disease, predation or other biological interactions. On Qikiqtaruk, trait-based negative frequency-dependent selection might be stronger than species-based negative frequency-dependent selection, because of the harsh environmental conditions might favour certain trait combinations. For example, evergreen species with small hardy leaves and large seeds or berries dispersed by animals versus deciduous species with large fleshy leaves and small wind dispersed seeds. We have observed high variance in traits both within and between species. Different evolutionary mechanisms and modes of selection could promote overdispersed tundra plant communities – with trait combinations spread across the phylogenetic tree.

Environmental variability within the growing season further maintains different reproductive strategies. For example, Salix richardsonii (Richardson’s willow) and Salix pulchra (diamond-leaf willow) flower early in the season before they leaf out in spring, whereas Salix arctica (Arctic willow) and Salix glauca (grayleaf willow) flower later, after green up and during the peak of the growing season. Here in the Arctic, selection fluctuates on both short timescales within the growing season and long timescales among seasons and over years. Most of the species are hardy perennials, so if conditions are really unfavourable in one year, they can hold off reproducing until the next, an example of “buffered population dynamics”, as outlined in Mark’s book. Even within the tundra landscape different environmental conditions exist with exposed ridges and snow patches where plant phenology, community composition and plant traits differ. Environmental variability over space and time likely dominate selection processes in the tundra biome.

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Snow patch near Pauline Cove

In our first book club blog post , we told you about the two distinct vegetation communities we study – the Herschel type (dominated by Eriophorum vaginatum tussocks) and the Komakuk type (dominated by grassy species and bare ground patches). With the exception of perhaps little patches of tundra around and about, we haven’t observed an intermediate community state, suggesting that there are positive feedbacks in place, which push communities to either the Herschel or Komakuk vegetation type. But, what are the mechanisms which underpin the maintenance of these two different plant communities, and what selective forces are at play?

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Herschel (left) and Komakuk (right) plant communities

A highlight of Mark’s book for us have been the summary tables in each chapter on the four high-level processes. We love hypotheses, and the tables summarising the hypotheses linked to selection spurred much discussion in our island book club. We couldn’t help but pick out the ones which we consider to apply most to the Arctic tundra, as well as the ones we have been testing in our work – and make a table of our own.

Table 1. Hypotheses and predictions for selection in plant communities and the links to our work on Qikiqtaruk-Herschel Island.

Hypothesis Prediction Links to the tundra biome and our work References and ongoing work
Constant and spatially variable selection Composition-environment relationship across space

 

We have been investigating how composition-environment and trait environment relationships shape the tundra biome, the extreme edge of life on planet earth. Elmendorf et al. 2015, Bjorkman et al. in prep., Thomas et al. in prep.
Large variance in traits locally Tundra traits do vary locally both within and between species and as intraspecific trait variation (ITV) is very important for studies at local scales (sites less than 100 km apart). Bjorkman et al. in prep., Thomas et al. in prep.
Change in environment leads to change in species composition A big disturbance event such as active layer detachments might have facilitated the establishment of Komakuk communities, which are then maintained by smaller-scale cryoturbation. Overtime climate change and reduced rates of cryoturbation might be leading to an increase in plant biomass and a change in community composition. Qikiqtaruk Ecological Monitoring Team et al. in prep., Bjorkman et al. in prep., Elmendorf et al. 2015
Positive relationship between species diversity and spatial environmental heterogeneity We are using drones to map microclimate, a metric of environmental heterogeneity, to test this prediction! And this is something that could be explored across tundra sites using future data from the HiLDEN network. See future manuscripts…
Negative frequency-dependent selection Species increase when rare or decrease when dominant at equilibrium We haven’t found support for this per se, as from our observations, in the tundra rare species tend to stay rare, and dominant species tend to maintain their dominance – though some of the dominant species do seem to be becoming a bit more dominant, though this could be under non-equilibrium conditions with increasing growing seasons, changing active layer depth, etc. Qikiqtaruk Ecological Monitoring Team et al. in prep.
Trait overdispersion locally We have observed trait overdispersion in the tundra, as there are many different strategies to survive the cold conditions and very short growing seasons. Thus, trait combinations are represented across tundra plant phylogenies, covering almost the entire extent of global trait variation except along the height/seed size axis. Thomas et al. in prep. and see future outputs of the ArcFunc Working Group
Temporally variable selection Composition-environment relationship across time The long-term environmental monitoring on Qikiqtaruk and elsewhere in the tundra biome are allowing us to study how composition-environment relationships in the tundra change through time. Qikiqtaruk Ecological Monitoring Team et al. in prep., Bjorkman et al. in prep., Elmendorf et al. 2015
Community-level trait environmental relationship across time Out of the species traits we study, height is the only one demonstrating a strong trait-environment relationship over time. Bjorkman et al. in prep.
Positive relationship between species diversity and temporal environmental heterogeneity We suspect this prediction is not valid in our island context, as the floodplain here is the most temporally heterogeneous habitat, yet it is not very diverse. Instead, topographic diversity might be the driver of higher species diversity. No manuscripts planned at the moment, but maybe we should write something about this!
Positive frequency-dependent selection Community dynamics sensitive to initial composition Once the Herschel and Komakuk communities have established, they appear to be maintained across the landscape, thus the initial composition is influencing which, if any, new species colonise. Again, no manuscripts planned, but it could be fun one day to experiment with artificial communities and initial conditions – though tundra plants are quite slow growing and long lived, making these experiments a challenge.
Positive intraspecific feedback via environmental modification In the Herschel communities, the Eriophorum vaginatum tussocks create a specific microclimate, which is favourable for other species. For example, Stellaria longipes is present in both Herschel and Komakuk communities, but appears to do much better in the Herschel vegetation type. Similarly, nitrogen fixers, like Lupinus arcticus, alter the habitat and facilitate the persistence of other nitrogen-loving species. Maybe it is time for a Qikiqtaruk plant biodiversity patterns manuscript?
Multimodal community composition That is definitely the case on Qikiqtaruk, where there are two very different communities – Herschel and Komakuk. See Table 2 for environmental differences between the two communities as proxies for differences in selective pressures. Qikiqtaruk Ecological Monitoring Team et al. in prep.

Table 2. Different environmental factors potentially influencing selection in the two dominant vegetation communities on Qikiqtaruk-Herschel Island.

Komakuk Vegetation Type Herschel Vegetation Type
Deeper active layer Shallower active layers
More cryoturbation Wetter soils
More N fixing lupines More acidic soils
More disturbance-loving grasses (Alopecurus alpinus, Arstagrostis latifolia) More microtopography

So, how do selective forces shape plant composition in the tundra biome and on Qikiqtaruk? Evolutionary adaptation and plastic responses to changing environmental conditions are as strong or stronger here as anywhere else on planet Earth.  It is here in the tundra biome – one of the coldest places on the planet – that the environment and species interactions dominate to determine the species composition that we observe across the landscape.  Probably Hubbell would not have come up with his ‘Neutral Theory’ if he were studying tundra plant communities instead of Barrow Colorado Island in the tropical forest of Panama, but that doesn’t mean that selection is the only force at play shaping tundra plant communities.  To find out more, stay tuned for our next blog post on speciation, dispersal and drift in the tundra.

By Gergana and Isla

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This blog post was written on Qikiqtaruk-Herschel Island in the Western Canadian Arctic as part of Team Shrub’s island book club, aiming to read and discuss Mark Vellend’s 2016 book “The Theory of Ecological Communities” while we are out in the field, right next to the communities we study.  Team Shrub are a group of plant ecologists who often work in high-latitude tundra ecosystems on topics in community ecology.

The team’s book club discussions are summarised in four blog posts: