Gardens, Plants and Climate Change

As we reported here on the Naked Scientists a couple of weeks ago, COVID-19 is a confusing illness - some doctors are dubbing it the weirdest disease they’ve ever treated. What makes it weird is the broad range of severity: some don’t even know they’ve been infected, while among others it can be lethal. Significant numbers of people are also reporting long term symptoms, including fatigue, sensations of pins and needles, and sometimes struggling to think clearly.So what’s causing this? Scientists think that the disease may be producing long term changes in a range of organs, possibly because of damage to those organs during the initial illness. Recently, researchers at Cambridge University sent samples from Covid-19 patients here to the Australian National Phenome Centre at Murdoch University in Perth. There, using very sensitive chemical techniques, they’ve been able to spot changes in a range of substances in the bloodstreams of these patients. These signature changes appear to be very specific for coronavirus infection, so they can be used as an accurate test for the disorder. They also provide insights into why people are developing some of the symptoms they are, and, in the future, may enable us to predict who is most at risk. Phil Sansom heard how from Jeremy Nicholson, who’s leading the study...

Jeremy - There is a very marked signature, in fact it's surprisingly strong. So what we see, is a pattern that's related to liver dysfunction, to diabetes, to potential cardiovascular damage and cardiac risk. The thing that makes it unique, is it has a multiple system failure signature, which means that it stands out like a sore thumb. We've never seen anything quite like it

Phil - Is this specifically for people who get really severe COVID?

Jeremy - It looks as though it's largely independent of the degree of respiratory symptoms, which is potentially quite surprising. But if you think about it, you know, there's been reports now of people having brain damage, strokes, heart failure, gut effects, kidney effects. And what we're seeing is the combination of pretty much everything that everybody's been talking about for the last couple of months.

Phil - How easy is that to detect for you?

Jeremy - We have various different types of advanced chemical equipment, and it's all based on spectroscopy, the study of the chemical signatures of molecules. Molecules can absorb energy, and radiate energy in lots of different ways. They can also have characteristic mass profiles, and it doesn't matter which one we use. There's always a signature for COVID-19.

Phil - In terms of this sort of being almost a test for who's been infected, how does it compare to the other tests in terms of how quick it is, how easy it is?

Jeremy - When we started the work back in February, I wasn't terribly interested in detection per se, because I made an assumption that the PCR methods for testing for the virus were extremely good. And it turns out there's a huge number of the tests that have very large numbers of false negatives, which of course is a bad thing for a test. And we're using NMR spectroscopy, we have a test that is 100% sensitive, that works in four minutes, costing about 15 pounds or something like that. And that is gender independent, age independent. It's also independent of severity.

Phil - You know, everyone talks about how strange this virus is, and how strange this disease is. And it's strange that the one constant, is how universally disruptive this is to people's bodies.

Jeremy - Yeah. There are probably a number of reasons for that. The most important one is this is a disease that attacks epithelial cells, cells that line or cover surfaces. So the lung has a double epithelium. It has the cells that face the air, and it also has the blood vessels, which are very, very close indeed. But the whole of the body is full of blood vessels. And there's lots of reports in the literature about blocking tiny blood vessels, and also major blood vessel blockages as well. And that means any organ in the body, technically can be affected by COVID.

Phil - Jeremy, when can we expect to be able to take your test?

Jeremy - Well, you can take the test in our laboratory tomorrow, but this is informally. The pathway to getting it to a test that could really work and be deployed at scale is not necessarily a long one. It might only be eight to 12 weeks in an ideal situation.

Phil - And I've been talking to lots of people who are still sick, after months and months and months. Does this discovery that you made give them any insight?

Jeremy - Well, that's an interesting question. So, at the moment we don't know enough about it. What we do know is in some people that we've looked at, we've looked at them several months after they've actually had an episode, and they're still mapping with the COVID positives who were in the hospital. When we monitor people, we'll be able to assess quantitatively, whether they are going back to normal. At the moment, we can't accelerate people going back to normal. But what we will be able to do, is to have a better way of assessing the health of people who've had COVID, in a long-term followup.

This week we are one step closer to a future of self-driving cars thanks to a new proposal the UK government is considering, which could see automated cars on the roads as early as next year. Our tech guru Peter Cowley told Eva Higginbotham more...

Peter - It's only a small step, but it's quite an important one. Basically, it's a call from the government for evidence for the safe use of automated lane keeping systems, or ALKS, basically staying in lane. So doing two things. One is not running into the car in front, of course, but also not leaving the lane, and although some cars already do that, they only do that with the driver having their hands on the wheel. In this case, this is actually allowing the driver to be aware, so it can take over if something goes wrong, but not be as involved as it would be at the current system. Of course, it has got to monitor whether the driver is actually still there. That he's still got a seat belt on, or her seatbelt on, monitoring eye tracking. It's got a black box in there, et cetera. And it will pass back control to the driver if it can't cope, but it's effectively the first time that the government's moving towards actually producing a legal definition of whether an automated vehicle can go on our roads or not.

Eva - Wow. So that's a truly hands-free type scenario. So what can, and can't self driving cars do already?

Peter - First of all, before we get too excited, these are under very strict conditions. This is an EU directive. It's being allowed throughout Europe from early next year. And this is only on roads where there's no pedestrians or cyclists, only when there's a central reservation. So basically only on the motorway or dual carriageway, and more importantly, no more than 37 miles an hour, or 60 kilometres an hour. Which means effectively, slow moving traffic. However, the UK government are trying to work out whether it's possible to do it up to 70 miles an hour, which is our speed limit in the UK. So how far have they got? There actually is no such thing as a self driving car on public roads yet. There are trials, and there are five levels of so-called autonomy. From the ones we see at the moment which are really levels one and two, to three, this is the first time that three, if it's allowed, will actually be on the road. But remember it's only in a single lane driving on a motorway, effectively. So it's a long way from the self-driving car.

Eva - I see, I guess one of the concerns is really, how much can we trust the average person to sort of use it safely and to also be paying attention while you know, having their hands off the wheel? What do we have to be wary of?

Peter - Yeah, that's a good question, because in fact, what it's trying to do is replace the average person with something that in principle should be safer. An automated system, if one believes in these things, means that they're less likely to make an error. So obviously they're not going to be drunk, or they're not going to be distracted by somebody in the back, et cetera, et cetera. So the average person isn't really relevant, it's whether one can trust the system to be effective, and mean that once it's enabled, that it works, but this person has still got to be available. They can't go and get a seat in the backseat, they've got to be available in case something goes wrong that the system can't cope with.

With changing temperature and rainfall patterns predicted by climate change, how might our gardens and vegetable patches have to adapt in the future? Ross Cameron is a landscape horticulturalist at Sheffield University and works on climate change mitigation; he’s co-authored a report for the Royal Horticultural Society on this topic, and he spoke to Chris Smith...

Ross - It's about extremes. It's about, generally speaking, drier summers and wetter winters, in a nutshell. There's some variation - Northwest Scotland, for example, might also have slightly wetter summers. But it's about pulling apart those weather conditions. So we're going to see drier spells for longer, but also wetter spells for longer. I guess one of the worrying aspects of it is it's not going to be a smooth ride. We're going to see a little bit more turbulence in the system. So we're going to see more oscillations, more extremes coming sometimes quite quickly after each other. So a very dry period followed by possibly a very wet period.

Chris - Of course, the plants that we are very fond of growing, and those plants that feed us very well, are not necessarily as fond of those sorts of changeable conditions as a weather person is. So what might be the implications for the plants we can grow? Do we expect that some things are just not going to be viable anymore? Is this the end of the English country garden?

Ross - We can deal with the weather by putting on a coat, taking the coat off sort of thing, but plants can't. Plants are very much in tune to their environment and the seasons. So they go through periods of acclimation so they can adapt to drought if they're given a bit of a chance to run up to that drought beforehand. So these conditions are quite challenging. We're going to see plants that are traditionally grown in warmer climates. They may adapt. They may be useful in the garden. We may see more of those types of plants. At the same time I think we're also going to see plants who are just kind of generally speaking more resilient, more tolerant to stresses in general, and trying to bring in that sort of resilience. Unfortunately, that often means the plants that are quite competitive, quite successful already. So things we might sometimes define as slightly weedy, they'll be the ones that are the survivors in some ways.

Chris - So in my case, lots of stinging nettles. When you were talking there I was thinking about the fact that if we do see a lot of rain all at once, we get these big deluges. Is there a risk that you could end up with leaching? So the rain comes down on the soil, it washes out nutrients. They go into the river, not good news for silting up rivers, but also not good news for the soil. So gardeners are then attempted to put more fertilizer on and that gets leached as well. There could be a vicious cycle there.

Ross - Yeah. So we're going to be careful about how we manage our gardens, not putting too many chemicals onto the system. We have some allies in that - we have things like organic matter. So the more we can recycle compost, recycle horse manure, all those sorts of things that have been traditionally useful for improving the soil. They're actually quite beneficial here because that soil organic matter helps act as a sponge and hold water when there's too much. But also it helps keep that water up when it gets dry and provide it to the plants. So all gardeners always say, feed the soil to feed the plants. And that adage is still quite true, I think.

Chris - And you mentioned water and keeping water in the soil, but what about keeping water not in the soil, but in things like water butts? Is this all going to be about better water stewardship? If we anticipate we're going to have a long run of dry days and we want to grow the same plants, we just need to make sure we store up water for the bad times when we've got the good times as it were.

Ross - That's right. If rain comes in bigger dollops, then we want to capture that and reuse it really for garden use. Rain butts are a great idea, but we're also seeing interventions in places like Australia and North America, particularly, in things like rain gardens. So you actually sculpt out some of the landscape where water can be held. That water runs off very quickly. You avoid it going into the houses and the roads and you collect it in certain places, and then that can then be pumped out to actually irrigate farms and gardens later or itself becomes a feature in the landscape. So it can be quite small scale things, or it can actually be almost at a community level that you're trying to capture and hold water.

Chris - Well, more on that sort of thing in just a second because I'd just like to play you, Ross, a little clip we recorded at a special dry garden that's being developed at the Cambridge University Botanic Garden.

Chantal - It's called the dry garden, because there's a permanent hosepipe ban in here.

Katie - There is no water in this garden?

Chantal - No irrigation, no watering. That's really the idea. It's surrounded on all sides with these quite tall hedges. Those can provide shade as well. Enclosed reduces impacts of wind. So if you can reduce that wind and you can provide the shade, then you are providing some sort of micro climate that allows some of the plants that may be less drought adapted to survive. But then you need to think about the plantings. And this comes back to selection of those kinds of plants that have that adaptations to the dry environment. But the practical activities to ensure that water doesn't get lost in this garden are things like mulching, so mulching often. Having this surface layer of organic material, bark cuttings, or minerals like gravel, all of that will reduce moisture loss from the soil surface. No lawn, permeable paving that allows the water to move through the landscape and doesn't result in if there is a heavy rainfall - now we're predicting more rainfall in winter on the other hand to drought in the summer - so you want to make sure that your surfaces are permeable, you're not going to increase your flooding.

Chris - So basically it's more sympathetic planting and a bit of forward thought.

Ross - Yes, indeed. Yeah. It's the right plant for the right sort of situation. And I think that will vary slightly in the different areas of the country. So the areas that are wet at the minute and get wetter you might be thinking of certain types of intervention and planting. Somewhere like East Anglia, the east side of the country, then you're thinking about things like scree gardens, where you're using dry adapted species more effectively. And you can get the balance right. You can keep these guys going quite happily in the summer, but keep the roots above any water table that might appear in the winter through slight changes of level in the garden and using things like was mentioned there - shale, and other sort of mulch systems.

Chris - Is it all bad news? Are there any silver linings to this longer growing season et cetera because the temperature's a bit different? Are there any things we can look forward to?

Ross - From the personal point of view, us, we will enjoy the garden more. We'll be outdoors more often. I think we will be using the garden as that outdoor room. And we will always obviously still grow plants and containers where you can, to some extent, mollycoddle them and look after them. So we will still have our special plants, our pets, but it may well be that we're actually having more time and using the garden more effectively just because we are having these longer summer dry periods.

We can’t talk about plant life without mentioning the animals that live in and around them. And pollinators are often in the news, with worries around declining numbers, and the impact on biodiversity and crop production. Andrew Bladon works at Cambridge University, where he’s done field work - literally - looking at how butterflies respond to temperature change. And he spoke to Chris Smith...

Andrew - So like many species, butterflies are showing effects of climate change at the population level. So we've seen that species are moving North in Europe and North America. And similarly to the plants that Chantal was talking about, species that are adapted to mountains tend to be declining and they're becoming more and more restricted. And there are also changes in behaviour. So species start to emerge earlier in warmer years. But all of these sort of population level changes that we can detect are likely to be caused by individual butterflies' responses to temperature. But we actually know very little about how butterflies respond on an individual level. So what we were trying to find out was exactly that - what do butterflies do to respond to temperature at fine scale? And can we link that to what's happening at a large scale?

Chris - And of course, the butterflies that do inhabit different environments that have different ranges of temperatures are going to be affected differently, in the way that you've just been identifying. So are there therefore some winners and some losers here?

Andrew - Yeah. So the interesting thing is that at the population level, research by butterfly conservation and long term monitoring over the last 40 years has shown that despite the fact that our climate is probably improving for the majority of species, about two thirds to three quarters of our species are still declining. The suspicion is that that's because there's still a big effect of habitat fragmentation and habitat loss on species. But within that, there are a few, a small number of species that are doing quite well. And species that are expanding their ranges northwards quite rapidly. And those generally tend to be the species that are more ubiquitous. They're the ones that can do well in lots of different environments. And they can survive in lots of different environments.

Chris - So the winners just win more and the ones that are already a bit vulnerable, they're finding it even harder to cope. Do you actually know, when you look at those winners and losers, do you know what it is that sets them apart? Why some are just a bit more resilient and some are more vulnerable?

Andrew - That's something that we've been looking at specifically in terms of how they adapt their behaviour to different temperatures. But I'm going to hold off a little bit on telling you the results of that, because we've got a paper coming out in a couple of weeks. So if you watch this space, there should be more answers coming very, very soon. In general, as, as you'd expect really, species that are more able to cope with a broad range of temperatures, those that are able to adapt generally to a wider range of temperatures, tend to be doing better. And those which are very specialist and have very specific temperature requirements tend to be doing worse.

Chris - What about the services they provide to the plants? I started this by referring to the fact they are pollinators. People often overlook the role of the lepidoptera - butterflies, moths etc - in terms of their contribution to the pollination effort. What has been the impact of these changes on what will be the impact of these changes on our plants and flowers and crops getting pollinated?

Andrew - Yeah, so you're exactly right. So about 85% of crops within the EU are insect pollinated. And most people assume that that's all done by bees. But in fact, honey bees, which people think of as the most common pollinators, only actually pollinate about five to 15% of crops, which leaves the other 85 to 95% to be pollinated by bumblebees, solitary bees, moths and butterflies, hover flies, beetles, and all sorts of other insects. And so actually the diversity of the insect community is really, really important for crop pollination and is estimated to be worth hundreds of billions of pounds annually.

Chris - And so if we take your findings and we extrapolate them to what the impact might be on pollination of crops, does that mean it's automatically a worrying picture? Or is it just that because we don't think the overall numbers of pollinators are going to go down, just the diversity is going to drop, actually, we probably will get away with it?

Andrew - The loss of numbers is worrying, but as you say, because some are going up, there's potentially some buffering there, but the thing is that because insect numbers fluctuate quite wildly from year to year. And so some species will do well in one year and then badly another year. And at the same time, a different species will do badly in the first year and well in another year. And by having that diversity of insect pollinators in the landscape, it means that actually we can be more resilient. So in any given year, we've got more options for the species that can pollinate our crops. The worrying thing is that if we lose some of that diversity, we become less resilient. And so there are fewer options for species to pollinate and therefore the chances of us having a really bad year where pollination fails becomes more and more likely. And, actually, the reliance that we currently have and is developing worldwide on the honeybee for pollination is particularly worrying. Because essentially if something bad happens to honeybees, we've lost the diversity of wild insect pollinators that could be able to pick up the pieces.

Chris - What can gardeners do to help?

Andrew - One thing is plant a wide range of wildflowers, to help give insects a helping hand, things that flower throughout the season. Another thing is to try and reduce the use of pesticides and herbicides because they are directly killing our insects. And the final thing is to try and actually be messier in the garden. Mow less, and leave some taller vegetation, which helps insects to survive through the winter.

Chris - Andrew, thank you.

We also put this to University of Sheffield horticulturalist Ross Cameron...

Chris - So, Ross, basically mow less, chuck fewer chemicals on, have a messier garden. Would you go along with that?

Ross - Yeah. In principle, I would. I mean, I think we can go back to nature a little bit in the design of our gardens in that the slightly rougher approach provides a lot of benefits. It's a benefit for wildlife, but even for what I mentioned earlier about capturing rain, holding water, the ability to provide a better microclimate for wildlife, but also for ourselves, goes along with a slightly more relaxed attitude to gardens. And at the end of the day gardens are places we want to enjoy. And quite a lot of enjoyment comes from seeing nature. So gardens without butterflies, without birds are pretty poor soul, really.

Chris - Lawn. A well manicured lawn is often seen as the thing we all aspire to, but actually one person described these things as a sort of biodiversity desert, a horrible mono-culture that's very, very demanding on our time, of our input and returns very little value. A) is that true? And B) therefore, should I get rid of my lawn? And if so, what should I replace it with?

Ross - Yeah, the green desert! Look, manicured lawns have their place. If you happen to be in the luxury of having a croquet lawn or a grass tennis court, it has to be close mown and functional. The reality is most of us do a lot of management of our lawns, which are not necessarily to our benefit. You can let the lawn grow a bit longer. You can get the wildflowers coming in. You can have the pollinators and insects, and you can also retain that degree of respectability. We're using what we call "cues to care". So if you cut paths where through it, if you keep certain parts of it tidy, you can actually still have the best of both worlds, nice legible walkable paths through the garden. And at the same time, allowing some rough and ready spots within the lawn that actually attracts the wildlife and provides that resilience.