Greening the Red Planet

By Sophie Harrington

It’s a big universe out there, and it takes a long time to get anywhere. Even just heading to Mars would take us over 6 months. A bit further than popping down to the pub then! But if NASA and a whole host of other private groups get their way, it won’t be too long before we’re sending humans out to Mars.

Mizuna growing on the ISS (credit NASA)

Mizuna growing on the ISS (credit NASA)

The logistics of the operation are still being worked out. Some argue it’s better to send astronauts on a one-way mission, setting up a bare-bones colony that will grow over time as more and more colonists make the voyage to the Red Planet. It would be handy not to carry all the fuel needed to launch a rocket off of Mars, but sending humans on a one-way trip might be a bit too much for NASA. Private groups, like Mars One, might seem more likely to support such a remarkable attempt, but it’s unclear where their funding will come from.

Whether or not we send humans to stay on Mars to begin with, it can’t be denied that colonising another planet would certainly capture the imagination. But what would that really entail? It’s well and good to talk about sending humans to Mars, but how on earth are we going to survive?

Enter plants, which will probably be our most prized possession on Mars, and in outer space for that matter. Even Apollo astronauts grew tired of their space-certified food, and they were only in space for a matter of days. While the food has definitely improved, the sheer delight of ISS crewmembers when they were able to have a few mouthfuls of fresh Mizuna, grown on the spacecraft, suggests it still leaves much to be desired.

Artist's conception of a greenhouse on Mars (credit NASA)

Artist’s conception of a greenhouse on Mars (credit NASA)

NASA recognises that to send astronauts on long-term missions, some form of fresh food will likely be necessary. Besides the culinary and psychological benefits of fresh veg, hardly any of the food packages currently in use on the ISS would survive the length of a trip to Mars. Sending astronauts up with lettuce, tomatoes, rocket, and even courgette could provide badly needed nutrition while livening up the interior of the spacecraft. Who said interior design wasn’t important in space?

Once on Mars, one of the first structures built by the colonists would have to be a greenhouse, where vegetables can continue to be cultivated. In the long term, we would be able to grow more intensive crops such as maize and wheat, which while requiring refining to be edible would help bulk up a diet, and reduce the dependence of the colonists on food supplies from the home planet.

Some researchers have even found that plants can grow perfectly well on Mars-simulant soil, in some cases even better than on Earth soil! Perhaps colonists may start gardening outside, beginning a process of terraforming that could change the face of Mars itself.

It might not be called the Red Planet for long!

Alien invaders or peaceful co-existors? The matter of non-native species in Britain

By Lilian Halstead

With the world becoming ever more connected, people are not the only things taking advantage of planes and boats to get around. Plant species are constantly being introduced, intentionally or otherwise, into places far outside their original range. The term ‘invasive species’ is sometimes used to refer to any of these non-native species. However, it more usually refers to species that are not native to the country they are growing in but that are able to propagate of their own accord and cause both environmental and economic problems. Not all species that aren’t native are invasive: in fact, it is estimated that out of all the new species arriving by human influence, only ten percent of those will survive in their new environment, and only ten percent of those will go on to have any measurable impact. But if you think of the number of plant species in gardens across the UK, that’s still a substantial number.

BeechAttribMost invasive plants in Britain start off as garden plants that spread to the wild either by releasing seeds or through being dumped as garden waste. Surprisingly, many invasive species are still being sold as garden plants despite their known detrimental effects on biodiversity. Parrot’s Feather is a water plant often sold as an oxygenator for ponds that forms thick mats of vegetation, blocking out light and choking waterways so much that they dramatically increase the risk of flooding. Ironically, Japanese Knotweed, now a notorious invasive species that would cost over £1.5 billion to eliminate from the UK, won a gold medal for being “the most interesting new ornamental plant of the year” when it was first introduced.

So introducing species for gardens can lead to invasive species escaping and causing ecological damage by forming monocultures that shade everything else out, and economic impacts such as exacerbating flooding or growing through tarmac. For this reason there are many schemes that act to monitor the species introduced to see if they become a problem and to hopefully prevent them from doing so in the first place.

But given Britain’s geological past, deciding what is native and what is not is a lot harder than it first appears. Many European species either did not make it into Britain before the English Channel cut Britain off, or went extinct soon afterwards, and humans then subsequently introduced many of them. Species that were introduced by humans a long time ago are known as archeophytes, and one such plant is beech, which was probably introduced 2000 years ago because the nuts are edible. For many species it is hard to tell whether they were there to start with or whether they were introduced. For species that were here once but went extinct before humans arrived, and which were then subsequently reintroduced, it’s not clear whether they should be counted as native or not.

KnotweedAttribIn addition to this, it has to be remembered that ecosystems are not static – succession and evolution are constantly changing the species composition, so trying to exclude species to keep things as they are is sometimes in the best interests of biodiversity, but it isn’t natural. Perhaps hybrid ecosystems altered by non-natives may have their own value, if given the chance to develop properly. Especially if further flow from the source location is halted, then the non-natives may speciate to some degree, which would make them worthy of protection in their own right.

Invasive species are a threat to biodiversity and do need to be controlled if native species are to survive. But the impacts of those that are less damaging can be positive, and given that species transfer is unlikely to stop anytime soon, seeing the value of newly emerging hybrid ecosystems may be a better strategy than attempting to maintain a ‘pure’ state, especially here in Britain, where most of what we think of as natural has been heavily shaped by humanity.

For more information, check out the GB non-native species secretariat, which has a database of most of the invasive species in Britain at the moment.