Species invasions and climate change: can grasslands cope?

Lizzie Jones and I contributed a chapter about grassland invasions to Grasslands and Climate Change, the latest volume of the British Ecological Society’s Ecological Reviews series. This is a blog post that Lizzie – a former MSc student of mine at Southampton – and I wrote for the Journal of Ecology blog.

Imagine a typical grassland ecosystem. You might see American prairies, rangelands of Australia, or African savannah. Either way, you’re probably thinking of wide-open spaces, dominated by resilient grass-like species. Yet, despite covering over 35% of the ice-free land surface, grasslands are an increasingly fragile ecosystem, experiencing some of the highest levels of exotic plant species invasion of all ecosystems. While there are strong links between levels of grassland invasion and human activity (as work by the Nutrient Network shows), climate change is also thought to be a key driver of such invasions.

© Getty Images

It is well established that there will be both winners and losers with climate change, where some species experience increases in range and population sizes, while other experience reductions. A key prediction nevertheless remains that exotic species invasion will increase with climate change, especially with rises in temperature and increases in extreme climatic events. Given that – like native species – individual exotic species can be helped or hindered by climate change, why does this remain a general prediction? It makes sense that some species will benefit from changes in climate regimes, and others will not, but why should some species experience an advantage simply because they are non-native?

In our chapter of Grasslands and Climate Change, we address these questions by concentrating on the effects of climate change on exotic plant invasion in global grasslands. We specifically ask whether climate change will favour exotic species, why that might be the case, and what sort of species (including their functional traits) will be favoured. In the chapter we used a systematic approach to review three key environmental changes that may give advantage to invasive species: changes in background climate conditions including temperature and rainfall; increased disturbance from extreme events such as storms and droughts; and human responses to climate change, either to mitigate its effects or to adapt to them.

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A warming and biodiversity grassland experiment at Cedar Creek Ecosystem Science Reserve: experiments like these provide insights into the impact of climate change, including species invasions. Photo by Jacob Miller.

Exotic species are well-adapted to capitalise upon change – their very invasion shows that that they are able to expand their distributions and deal with what might be unfamiliar ecological conditions. Increases in the frequency and magnitude of storm events, floods, fires and other disturbances will increase opportunities for invasion, and species that can reproduce and spread quickly will be particularly well placed. For example, some Bromus grasses can recover very rapidly when drought eases, which has allowed them to invade and convert woody scrubland areas in North America. The ability to seize opportunities and cope with a broad range of environmental conditions means that climate change will favour many exotic species – especially compared with native species, which may be less able to keep pace with changing conditions.

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Finally, humans have a huge impact on grassland invasion. In our efforts to mitigate, offset and adapt to our changing climate, we are unwittingly exacerbating the invasion of exotic species globally. A key culprit is the production of biofuel, such as Miscanthus species, now widely used in North America and Asia and predicted to spread with climate change.

So, to respond to the question “can grasslands cope with species invasions and climate change?” – native grassland species are certainly under threat not only by exotic species but by a multitude of human and climate-related issues. But, as this book shows, work towards adapting current conservation and management strategies is already underway to keep pace with our changing climate, not only in grasslands but in all other ecosystem types.

Lizzie P. Jones (Royal Holloway, University of London and Institute of Zoology, London, UK) and Jane A. Catford (King’s College, London, UK)


Grasslands and Climate Change is part of the Ecological Reviews series. BES members get 25% off all titles in the series when buying directly from Cambridge University Press. See also, David Gibson’s blog post: Grasslands and Climate Change.

PhDs and the mighty chequered flag

source: Alfie Stratton

It’s been an exciting time recently – a few PhDs starting, a few others finishing (with two in and two out in the space of a week!). Love it!

Angela Bartlett, Stefanie Kaupa and Harry Shepherd recently crossed the starting line.

Angela is investigating the impact of rates of introduction, and introduction bias, on the richness and composition of alien plant and vertebrate species assemblages. She is supervised my Tim Blackburn (UCL) and me.

Stefanie is researching the impacts of agricultural land abandonment and associated plant invasions on hydrology in the mountain environments of Nepal and Colombia. She is supervised by Mark Mulligan (KCL) and me.

Harry is examining the potential for plant-soil interaction to enhance ecosystem restoration. He is supervised by Bjorn Robroek (Southampton) and me.

Angela and Stefanie started at King’s in March, both funded by the London NERC DTP. Harry started at Southampton in October, funded by the NERC SPITFIRE DTP.

And across the finishing line (cue fanfare, cartwheels, balloons) are Saras Windecker and Esti Palma – looking suitably triumphant below.

Esti produced a stellar body of work on the opportunities and limitations of trait-based invasiveness research.

Saras expertly examined the impact of vegetation communities on carbon sequestration in freshwater wetlands.

Both were at the University of Melbourne, supervised by Peter Vesk and me (+ Peter Macreadie in the case of Saras). Watch this space for forthcoming publications. They’ll be crackers!

Biggest congratulations to Esti and Saras – such a massive achievement to submit a PhD thesis!! woo woo!!

Moving to King’s College London

In exciting news, I am taking up a new position in the Department of Geography at King’s College London in September.

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Bush House: home of King’s Geography (and my new office)

Founded in 1829 by King George IV and the Duke of Wellington (and featuring a duel, no less!), King’s is the fourth oldest university in the UK, and is one of the world’s top 25 universities.

KCL has one of the strongest Geography departments globally, with research and education that extends across physical, environmental and human geography. I will be in the Environmental Dynamics theme, connecting hydrological, geomorphological, atmospheric and ecological processes – right where I love to be!

Based at the Strand campus, with views over the Thames, it is hard to be more central – not just literally in terms of London itself, but figuratively too. As a global city, London is a hotspot of education, research, culture – and has incredible connections with the rest of the world.

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No excuses not to visit if you’re ever in London

If you’re interested in working or studying with me, or would like to visit, please do get in touch. You can reach me on jane.catford<at>kcl.ac.uk.

SciComm cartoons in multiple languages

Thanks to generous friends and colleagues (and a seemingly unbridled passion for editing in Illustrator?!), the cartoon of Introduced species that overcome life history tradeoffs can cause native extinctions is now in five languages: German, Indonesian, Mandarin Chinese and Spanish, plus English.

 

Not only was this exercise great fun, but I am aware that – as a nature English speaker – I enjoy the privilege of reading (the bulk of) international science and science communication in my first language. So, I thought that others – both inside and outside of the science, research and education worlds – would like the opportunity to do the same.

I’m unsure how widely these cartoons will travel – and how well they’ll reach their intended audience (i.e. speakers of these languages), but can’t hurt to try, eh?

Huge thanks to Sarah Fischer, Tina Heger, Decky Junaedi, Esti Palma and Chung-Huey Wu for translating them. Incredible efforts.

Please feel free to share widely, and use these cartoons for any purpose that you wish.

[if you click on the above images, you can click through to get the language that you want, and then download the image. If you’d like a higher resolution version, please get in touch]

How can exotic invasions drive native species extinct?

Catford et al 2018 cartoon

Read the full paper here: 

Catford, J. A., Bode, M. & Tilman, D. (2018) Introduced species that overcome life history tradeoffs can cause native extinctions. Nature Communications 9: 2131.

Invasions in Malawi, Zimbabwe & South Africa

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One of the many values of wetland plants. Elephant Marsh, Malawi

In November, I escaped the chilly dreariness of southern England and headed to southern Africa. It was a veritable feast of a trip for someone partial to warm weather, warm people and plant invasions.

Kicking off the trip was a week in Stellenbosch at the Centre for Invasion Biology for a workshop (run by the brilliant Ana Novoa) and CIB annual conference fun.

I then met up with Marije Schaafsma, Becks Spake and Ishmael Kosamu for a week in and around the (recently) Ramsar-listed Elephant Marsh (plus a workshop for good measure – superbly chaired by Marije) . I could write reams on all of this (on the whole “big” trip in fact), but I’ll let some photos do the talking instead.

Finally, to spice things up a little, I flew into Zimbabwe for a bit of coup action – and to meet with Nicky Pegg and co from the Dambari Wildlife Trust. Things were thankfully very chilled in Bulawayo, and we spent most of time admiring the amazingness of Zimbabwe, its landscape, flora and fauna. Just incredible. Big thanks owed to Phil Riordan and the conservation team at Marwell Wildlife for the introduction.

Lots of cool research opportunities and collaborations in all of these places, so looking forward to southern Africa mark 2.

 

CIB workshop
Apparently my only photo from a week in Stellenbosch: how negligent of me. Quality not quantity though –– and look at the quality we have here?!

PhD on ecosystem restoration & plant-soil feedbacks

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Grass: more engaging than Game of Thrones. 

Applications are now open for a fully funded PhD position at the University of Southampton, UK starting in the 2018/2019 academic year under the supervision of Bjorn Robroek, Robert Griffiths and me.

PPN_2017

The project will examine the potential for plant-soil interactions to enhance ecosystem restoration with opportunities to work in Swedish peatlands and US grasslands.

Information about the project and how to apply can be found here. Applications will close on 5 January 2018.

Please contact me on j.a.catford@soton.ac.uk with additional questions.

Sunshine and visitors

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Esti, Luis and Alan make the most of the sunshine at New Forest NP

Long days, warm weather, dry roads and visitors. I love summer!

Esti Palma from the University of Melbourne and Dr Luis Mata from RMIT University (and, the all-important, Alan Mata) came to visit for a couple of weeks recently. They both gave excellent talks to our ecology group in Biological Sciences.

Luis spoke about “The Little Things That Run the City”, drawing on the pioneering work in Melbourne where Luis and other folk from RMIT are joining forces with Melbourne City Council to bring biodiversity into the city – and to make people aware of, and value, it. They’ve produced a beautiful children’s book as part of this work. I’m looking forward to seeing the other things that this innovative and productive group produce.

Esti focused on her invasive species traits work where she is using 80 plant species to test whether it is more informative to separate invasive species into different “types” based on their dimension of invasiveness, or whether it doesn’t matter if all species are lumped into one category. Early results seem to point to the former – but watch this space!

Esti also spoke briefly about her work that shows trait-based trends in the types of species that are being both lost from and gained in cities. As a bit of extra excitement, Esti’s paper featured on the cover of Ecography.  

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John and fellow Southamptonite, Bjorn Robroek, enjoying a cleansing ale after a walk along the River Itchen (we did talk ecology, promise!).

While talking about sunny visitors, it would be remiss of me not to mention Dr John Dwyer from the University of Queensland who stopped to say hello in June.

John also educated us with a talk, this time on how trait covariance can help us understand biodiversity trends along environmental gradients. Some really lovely work by John and Daniel Laughlin.

 

Three days of plant ecology in Germany

Journal of Ecology Blog

Journal of Ecology Associate Editors Jane Catford and Rob Salguero-Gómez were both keynote speakers at this year’s PopBio conference. Here is their report…


A few weeks ago, we had the privilege of attending PopBio2017 in Halle, Germany.

This was the 30th annual conference of the Plant Population Biology Section of the Ecological Society of Germany, Austria and Switzerland (GfÖ). Though hosted by GfÖ, the conference was very international in flavor, with all presentations in English. There were 130 researchers from over 20 countries, including the UK, Germany, Czech Republic, Brazil and South Africa, in what turned out to be a 1:1 gender ratio.

popbio1 Attendees at a presentation at PopBio 2017 (Credit: RSG)

It was an incredibly stimulating, fun and well-organized three days, with a lovely balance between unstructured (social) time and scientific talks and posters. Massive thanks and congratulations to the organizers, who put together an excellent…

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Wet wetlands restore better

What the Great British Bake Off can teach us about wetland restoration – some notes from Samantha Dawson

The Applied Ecologist

With Plant Conservation Day in mind, Samantha Dawson’s post discusses characteristics of wetland plants and her new paper, Plant traits of propagule banks and standing vegetation reveal flooding alleviates impacts of agriculture on wetland restoration.

Many of the world’s wetlands are highly degraded and they are one of the most threatened types of ecosystems. To attempt to halt or reverse this trend, there are lots of small and large restoration projects underway in many places. One of the most widely-used restoration methods is to re-introduce flooding to degraded wetlands, with the idea that if you provide water, the plants that were there before will return. Unfortunately, we haven’t had much success predicting the outcome of these restoration efforts and we do not always understand why restoration succeeds or fails.

Dawson_wetlands2_May17 Dawson explains that understanding how different filters affect plant traits means we may be able to predict and manage restoration more…

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