Tag Archives: climate

Johanna Schmitt: Climate Change and Plant Life

We sometimes ignore the effects of climate change on plant life, but the potential severity of these effects isn’t something that should be ignored for long (Image Credit: Pisauakan, CC0)

From the California wildfires to the recent strikes across Australian primary schools, climate change is a topic that only seems to grow in its ubiquity. Yet whilst humans are increasingly focused on more obvious repercussions, such as extreme weather events, animal extinctions and shifting coastlines, we sometimes forget that climate change will have severe repercussions for plant life as well.

I spoke to Professor Johanna Schmitt of the University of California earlier this year to discuss some of those repercussions. Johanna’s team is working to determine how well certain plant species will be able to adapt in the face of rapid climate change.

Sam Perrin (SP): The term climate change is ubiquitous these days, yet we often don’t talk about plants in relation to its effects. What will some of the effects of climate change be on plant life?

Professor Johanna Schmitt, Department of Evolution and Ecology, University of California (JS): Well from a North American perspective, let’s start with seasonality. The growing season is longer, spring is coming earlier, summers are hotter, winters are warmer. And so in a lot of temperate areas trees are leafing out earlier. And in colder areas, there’s potential that they won’t be adapting to the warmer weather, and will continue to act on temperature cues, which would be bad. There’s definitely evidence of changes in phenology, in seasonal timing of phylogenic effects. There certainly is already evidence of shifts northward in some plant species, and local extinction of species in their southernmost populations.

Looking at California, we’ve just come out of a mega-drought. We have cyclical droughts, and they’re getting worse because the temperature’s rising. Among other things, it means the snow packs are much lower in California. That means water supplies are lower, because there’s less and less water from the melting snow pack. If precipitation all comes as rain in the winter, then that reservoir of snow is not there, so there’s no water in the summer for the farmers. And that also means the species in the mountains which previously relied on the water from snow melt can’t get through the summer. So we’re seeing pretty massive forest die-offs. And then in addition to that you have the bark beetles, which decimate trees. In parts of the western United States, these bark beetles can produce an extra generation if the winters aren’t cold enough and so the populations expand. I was hiking in the Rocky Mountain National Park a few years ago and the trees had been torn to shreds by these bark beetles.

And off the back of all this we’ve obviously had huge fires. This last fire year in California was record horrible. That’s something that affects plant life that then affects humans big time.

SP: Will the agriculture industry have to start adapting?

JS: There’s a group at Stanford who have been trying to figure out if there’s a signature of temperature affecting crop yields by looking at historical data. And it appears that higher temperatures are affecting crop yields and they expect that to become an issue in the future. This idea that if there’s more carbon dioxide, that will help fertilise the crops and they’ll do fine doesn’t seem to hold if you go beyond critical temperatures. Bottom line is, yes, people are concerned about crop yields being affected.

SP: Things like drought and forest die-off have become more extreme these days. But there’s a danger of this becoming the new norm for people. How do we fight those shifting baselines?

JS: It’s a really interesting concept. Because the younger generation doesn’t remember stuff that my generation does. For kids today, these California wildfires will be the new normal. When I was a little girl growing up outside of Pennsylvania we used to go ice-skating on the ponds all the time after they would freeze in winter. Nobody does that anymore because the ponds don’t freeze.

You look at the record of temperatures. I take Introduction to Biology lectures, and I show the carbon dioxide curve from Mauna Loa in Hawaii, and I show them that when I was born, CO2 was 320 parts per million, and then show them the increase just in their lifetime. So now, being over 400ppm is the new normal. Kids today won’t ever remember it being less than that. People are getting more used to extreme heat events which we just didn’t have 50 years ago.

Arabidopsis thaliana, which Johanna's lab works with, is a handy model species for looking at the effects of climate change on plant life

Arabidopsis thaliana, which Johanna’s lab works with, is a handy model species for looking at the effects of climate change on plant life (Image Credit: Dawid Skalec)

SP: To what extent can we predict the adaptation of some of these species to climate change?

JS: Not very well, that’s really the take-home message. Foresters have the best ability to do that because they’ve been doing large scale trials, taking genotypes from across a species’ range and growing them in different climates across that range. By doing that you can ask how different genotypes perform in different climates. And that allows you to say how much variation is there within the species across the range, and you can also look at how much variation is there within populations. Take something like budset, the timing of when to set your buds and cease growth, shut down, and go dormant so you don’t get killed by the frost. It’s a pretty hard deadline for conifer trees. But from year to year the frost comes at slightly different times. So some years genotypes that are more risk-averse do better and some years others that are more risk-prone do better, so they’d have alternate good years. And this means variation can help a species persist in a changing climate

So for forest trees there may be a fair amount of potential for adaptation. And now people are starting to look at small endemic plant species. Jill Anderson at the University of Georgia has been doing some really interesting work of late on adaptation to elevation across an altitudinal gradient. They combined genotypes at low, medium and high elevations, and combined those mixed gardens with snow manipulation. They either removed or added snow, and they found was evidence of adaptation for the species which were exposed to snow. So that suggested that the population may have trouble keeping up if we have a declining snow pack.

SP: Why is predicting these changes so difficult?

JS: Well for one thing we don’t really know what scenario we’ll be looking at in a few years. I’m pretty pessimistic given events of the last few years that we’re going to have anything but an aggressive carbon emissions scenario. I think it’s going to depend upon the species. We’re going to have to help out. I think many species are not going to be able to evolve fast enough in place. So we’ll have to intervene with assisted gene flow, but how do we choose which ones we want to assist?

SP: Can you take me through the concept of assisted gene flow?

JS: So we want to find out which climate a species likes and where’s that climate going to be in the future. There’s some cases where in fact the species range in the future will be almost non-overlapping with the range it’s in now. So how’s it going to get there? After the last glacial maximum, when the glaciers retreated the trees were able to keep up, but that was happening in orders of magnitudes slower than the rate that the climate is changing now.

The idea is for crucial keystone species, species that are important to the ecosystem, that we should be helping them to move. And that’s very controversial. Because are you essentially engineering species invasions, with limited knowledge of what that will do to the community that is already there. Assisted migration isn’t that aggressive. The idea is that within an existing species range, you move genotypes around to maximise the genetic variation to cope with the climate that’s coming. So in general that would be making sure you’re saving all the genotypes you can from that southernmost edge before they go extinct. And then moving them polewards to provide genetic material for the new climate.

To read up on the work that Johanna’s lab does, click here.

The Shifting of Ecological Baselines

Bushfires like the ones that have ravaged Australia and California this year could become the new norm for the generation that has been born in the last decade, an example of how our perception of ecological change is defined by what has happened in our lifetime

Bushfires like the ones that have ravaged Australia and California this year, could become the new norm for the generation that has been born in the last decade, an example of how our perception of ecological change is defined by what has happened in our lifetime (Image Credit: dm4244, CC BY-SA 4.0)

It’s no secret that our world has undergone rapid changes in the last few decades. Extreme weather events are becoming almost the norm and species seem to be going extinct every minute. But as depressing as this may seem, the general doom and gloom we hear about the world on a daily basis still only represents a small percentage of the ills we’ve inflicted on our planet since we’ve been here.

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Crossing the River Between Fishers and Fish Science

"We need the next generation of scientists to be at the coalface, communicating good scientific information."

Some fish scientists, like recent ASFB delegate Jarod Lyon, have regular contact with fishers who benefit from the work academics and researchers carry out on fish. But is there enough of this sort of communication between the fish science community and fishers? (Image Credit: Jarod Lyon, CC BY-SA 4.0)

When a food source provides almost half a planet with protein, you can expect the people who deliver that food source to play an important role in society. Fishing is no exception. Any country that has a marine or freshwater ecosystem in close proximity will have a fishing community, and that community can play a variety of roles, from something as simple as putting food on people’s tables to campaigning heavily to keep your country from joining the EU.

So it makes sense that fishers should have access to good fish science, at every level. If you’re a multi-million-dollar corporation, you need to know how fish stocks will respond to certain catch levels over a sustained period. If you’re a local or specialised fishing community, you need to know how available your catch will be in five years given temperature increases. And if you’re one person on a boat in a river, you might want to know how best to treat an over- or under-sized fish to ensure it survives being released.

It follows, then, that there should be open communication between fish scientists and fishers. At this year’s Australian Society of Fish Biology conference, I asked a variety of delegates a simple question: Is there open communication?

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If You Can’t Stand the Heat, Get Out of the Pond

Dragonflies like this Western Pondhawk female are particularly vulnerable to warming due to climate change. (Image Credit: Eugene Zelenko, CC BY-SA 4.0)
Simulated climate change increases larval mortality, alters phenology, and affects flight morphology of a dragonfly (2018) McCauley et al., Ecosphere, doi:10.1002/ecs2.2151

The Crux

Climate change is something that we hear about on a daily basis. The dire warnings tend to concern sea levels rising and temperatures varying so much that we have more intense and deadly storms than before, but these are all direct effects of the climate. Another thing that climate change can do is have indirect effects on organisms.

Organisms with complex life cycles spend the juvenile part of their lives in one environment before moving on to the adult stage in another environment. The researchers in this study wanted to know how simulated climate change during the juvenile stage of the organisms lifetime could affect the adult stage.

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An Abridged History of the California Wildfires

California is ablaze, again. So why is this part of the world so notorious for catching fire?

California is ablaze, again. So why is this part of the world so notorious for catching fire? (Image Credit: Daria Devyatkina, CC BY 2.0)

Recently, I was looking for skiable snow in central Norway when I bumped into a chatty Norwegian man. When I told him I was Californian, he asked why my state was always on fire. The story demanded vocabulary beyond my grasp of the language, so this story is for your benefit, my random friendly Norwegian. This is a story of resource mismanagement, of urbanization, Pocahontas, and a policy that was a bear’s favor.

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Refining Nemo: Musings from the Australian Society of Fish Biology Conference

The Australian Society of Fish Biology's 2018 Conference delivered some of the most engaging, intriguing talks I've had the pleasure of witnessing

As a fish ecologist living in Norway, it’s a joy to be able to travel to Melbourne and interact with the people that are driving forward fish science in my home country. So when I found out that the Australian Society of Fish Biology’s annual conference was taking place 3 days after my first flight home since 2016, I knew it was an opportunity I couldn’t pass up.

We’re on the last day of the conference at the moment, and over the next 2 months I’m looking forward to bringing you a number of insights, including interviews with guest speakers Eva Plaganyi and Gretta Pecl and pioneers of intriguing projects like Peter Unmack and Jarod Lyon. I’ll also have a fish edition of The Changing Face of Ecology, and some articles on how the angling community and the fish science community interact in a country with one of the most unique fish assemblages in the world.

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