Dr Helen Taylor | Royal Zoological Society of Scotland
Zoologist Jane Goodall famously once said: ‘you cannot get through a single day without having an impact on the world around you’. One of the largest impacts humans have had on the natural world, over many thousands of years, has been to increase the extinction rate of species. The continuing loss of natural habitats, due to human use of land and sea, is today resulting in a global accelerated extinction rate; a rapid decline in biodiversity; and the degradation of many ecosystem processes.
In Issue 16 of EPOCH, we explored the theme of Environments, and had the pleasure of speaking with Craig Macadam, Conservation Director at Buglife, about the conservation of the Medicinal leech, in partnership with the Royal Zoological Society of Scotland (RZSS).
The RZSS aims to reverse the decline of fifty species by 2030 – from Pine Hoverflies and wildcats in the Cairngorms National Park, to Giant Anteaters in Brazil. EPOCH caught up recently with Dr Helen Taylor, Conservation Programme Manager at the RZSS, to discuss the history of human impact on the natural world, and the importance of the RZSS’ conservation efforts in preventing such a wonderful array of creatures from becoming extinct.
Could we start by asking you to tell us about the history of the Royal Zoological Society and its conversation efforts?
The Royal Zoological Society of Scotland is a wildlife conservation charity that includes the Highland Wildlife Park, where I’m sitting today, and Edinburgh Zoo. We have a conservation department, and we’re working on around twenty different conservation projects at any one time.
My team works on invertebrate breeding for release projects, on-site biodiversity work, Pallas's Cat conservation in Central Asia, and I also work to support our collaborators out in places like Brazil, conserving species like Giant Armadillos and Giant Anteaters, and doing large-scale habitat restoration.
Our strategy runs until 2030, and the strategy is focused on conservation, community, and engagement. Basically, those are the three areas where we think we can have a big impact. Our main conservation goal for 2030 is to reverse the decline of fifty species, which is a pretty tall order.
So, it’s a really wide and varied remit! We do a huge array of different stuff behind the scenes where people don’t always see what’s going on.
Could we hear about the armadillos you mentioned?
Yes! We’ve been partnered with a charity in Brazil called ICAS for well over a decade now. They focus their work on Giant Armadillos and Giant Anteaters. Giant Armadillos are this incredible sort of prehistoric-looking creature. They're about the size of a labrador. It's a big animal, so they can't curl up into a little ball like the armadillos that you might be familiar with. It's a much, much bigger sort of stranger-looking creature. They’re super important ecosystem engineers, because they’ve got these huge front claws that they walk around on, which are very strong, that they use to dig into termite mounds. But they also use them to dig burrows to shelter in.
A big part of the work of ICAS has been putting up camera traps, and they discovered that hundreds of other species use these burrows as shelter, or places to feed. So, the modifications that the Giant Armadillos are making to the landscape are very important.
But they can also get into human-wildlife conflict situations. For example, Giant Armadillos have come into conflict with beekeepers, because they knock over hives to try to get to the bee larvae inside. Beekeepers tend to put poison down to kill them, and the poison kills lots of other species as well. A big focus for ICAS is their ‘Armadillos and Honey’ project. It involves working with the beekeepers to put in fences, or raise the hives, so the armadillos can’t get to them. The beekeepers that sign up get to put a sticker on their honey to say it is armadillo-friendly, which means they can market it as a more premium product.
Are there any British animals whose history you find particularly interesting?
I’ve worked on big, fluffy species like beavers in the past, and obviously that has its own fascinating story. But the work that we do at the moment on invertebrates, I’m super passionate about, because I think those species get completely overlooked, but they’re the species that keep our ecosystems together. If we want to be doing projects on big, exciting, fluffy species like beavers and wildcats, then we have to be looking after these guys as well.
We’re working on Pine Hoverflies, Dark Bordered Beauty Moths, Small Scabious Mining Bees, and Pond Mud Snails – all species that are extremely threatened, with restricted ranges, that we are set to lose from Britain.
How have interactions with humans affected these species?
The main threat is habitat loss, degradation, and fragmentation. It is a common theme and is down to changes in how people use the land. Whether that is deforestation, changing land use for agriculture, or housing. When you are looking at aquatic species like leeches, and Pond Mud Snails, the way that we’ve diverted our waterways, and the pollution that we’ve caused in them, is massively problematic.
In our interview with Craig, we particularly enjoyed hearing about the trade in Medicinal leeches. Are there any other similar histories of British wildlife being negatively impacted by trade in the past?
Beavers are a great example of an animal that disappeared because it was hunted to extinction for commercial reasons. They were hunted for their fur, but also for castoreum, which is a substance that they secrete through a gland that is in their butt. Castoreum is used by beavers to send scent messages to one another, so it holds scent very well. It was used in perfume, and to hold flavour in things like ice cream!
We’ve read about the RZSS’s work with beaver re-introduction into Scotland. How are things going?
The RZSS has been working with beavers since 2009. We worked on them as part of the Scottish Beaver Trial, which was a partnership between ourselves, the Scottish Wildlife Trust, Forestry and Land Scotland and Nature Scot, and that was the first official licensed release of beavers back into the UK. It involved bringing sixteen animals across from Norway and releasing them into the Knapdale Forest Reserve on the west coast.
Between 2017 and 2020, we ran the Beaver Reinforcement Project, again in partnership with the Scottish Wildlife Trust. This involved us introducing additional beavers into Knapdale with a different genetic background. All the original beavers in Knapdale came from Norway, and we saw that the Norwegian population had quite low genetic diversity overall.
The illegal reintroduction of beavers in Tayside involved beavers of Bavarian ancestry, and we knew that they had different genetic material, so we decided to move some Bavarian beavers to Knapdale. The idea is that they mix and mingle with the Norwegian beavers, and you get some different genetic combinations which would be really, really cool to see. If it works, it will be very exciting, as it is important to have genetic diversity if we want a sustainable population of beavers in Scotland.
Looking a little further afield, we’d love to ask about your conservation research in spectacular places like New Zealand and the Peruvian Amazon. What sort of ecological histories did you come across, and what types of species were you studying?
Okay, yeah! It’s a real variety over a long period of time. I travelled to New Zealand initially to study for my PhD, which was on the Little Spotted Kiwi, which is one of the five species of kiwi they have in New Zealand (most people think there’s just one, but there’s not). I did four years on that, and another four years working on a couple of passerine birds, the South Island Robin and the Hihi or Stitchbird.
Then I came back to work for the RZSS, mainly in Scotland, but also getting to travel to places like Brazil. The thing for me is some people are species people, right? They work on one species, they love that species, that’s their thing they specialise in. I’m very much a question person.
What I'm really interested in is questions about how we can do better conservation management, how we can help different species, and how we can take what we learn and apply that to other species.
I'm really tempted to ask about the Little Spotted Kiwi!
You can if you like!
The Little Spotted Kiwi is the smallest of the five species of kiwi found in New Zealand.It's about the size of a chicken. New Zealand has no native mammals apart from a couple of bats. When humans pitched up (originally Māori, and later on the Europeans) they brought mammals with them: rats, cats, mice, dogs, ferrets – all these different things. And none of the biodiversity that existed in New Zealand was prepared for this at all.
Some birds like the kiwi cannot fly, and there were birds that can fly but still nest on the ground – they were all completely decimated by predation from introduced mammals. Many of the native species in New Zealand went down to very, very, small numbers, and the Little Spotted Kiwi were no different. The current population is around 2,000 birds, but they are descended from at most three individuals, who were taken to a place called Kapiti Island in the early 1900s where the species survived and persisted.
All Little Spotted Kiwi alive today are descended from those three birds, and the whole population of Little Spotted Kiwi live on islands, or in fenced sanctuaries within the mainland, to protect them from mammalian predators. As kiwi famously cannot fly, any movement of birds is done by human intervention.
What I looked at was whether any of these populations suffer from inbreeding. There is an idea that because species in New Zealand have been through so many population contractions, they may now be somehow “immune” to the harmful effects of inbreeding. As geneticists, we thought that doesn’t fit with what we know about population genetic theory. We went and collected data and found that, actually, Little Spotted Kiwi in certain populations definitely are suffering from inbreeding depression.
The fact that they live for up to sixty to eighty years in the wild was masking the problem. You could have, for example, an island with two founders. The two founders are still alive and reproducing, but all their offspring obviously had no choice but to mate with their siblings. The offspring of those sibling pairings were not surviving and reproducing. So, your population structure was two founders, a lot of first-generation individuals, and then nothing underneath. As soon as the founders die, the population will start to collapse.
To jump back to Scotland, we enjoyed talking to Craig about breeding Medicinal leeches. Could we ask you to tell us a little bit about the role that Medicinal leeches play in the Scottish ecosystem?
Everyone asks this question, it’s a really fun one! That is not a negative at all, it’s just that often what people want to understand is what does this animal do for us? Why should we care, why should we save this species? And that is a perfectly valid question to ask because we have limited resources for conservation.
There is a really good analogy that Paul Ehrlich, an American conservationist, often uses, which is about the rivets in an aeroplane. An aeroplane is held to together by lots of rivets, and if you take out one of them, the plane won’t fall out of the sky. But if you keep taking rivets out, eventually you will hit the crucial rivet that causes everything to fall apart, and the plane will fail and come crashing down to earth.
That is how I think about invertebrates like leeches. All the invertebrates work as a part of the ecosystem and we might not notice what we’ve lost. And if we don’t notice something being lost or see any immediate effect of that we might think it can’t have been that important. And maybe in isolation, it wasn’t. But the more of things like leeches that we lose, the closer we get to the plane falling apart as the ecosystem collapses. And we don’t understand why, because we weren't thinking about all those rivets and what was happening to them. That is why we should care about things like leeches.
Given what we’ve discussed about genetics, are there any concerns about the small population that forms the base of the Medicinal leech conservation breeding programme?
Yes, it is a concern. What we must do in the breeding programme is maximise genetic diversity as much possible. We just got back from a trip to Oban, where we collected four more adult leeches to add into our population. There are three lochs there, that are connected, but the leech populations are a little separated. We managed to get a pair of leeches from the middle loch, and the rest from the top loch. Hopefully this will add some genetic diversity into the population. But there is only so much we can do, because the genetic diversity within the Scottish population is potentially quite low to begin with. Our aim is not to lose any more diversity, so we think very carefully about how we pair our leeches up.
If you had to pick one thing that you’re most excited about in the next few months, what would it be and why?
I’m looking forward to this year, there are a lot of firsts happening. This will be our first breeding season for Medicinal leeches. I don’t know how much Craig told you about how they reproduce – it’s crazy! They produce cocoons, by making a slime out of their body, which hardens into this little sponge, and they lay their eggs in that to protect them. They’re actually really good parents. And then all these tiny little leeches hatch out, which I think will be very cute!
Is the intention with the Medicinal leeches to introduce a pilot population, or to continue to release leeches into the wild?
I think that’s a really key question to ask, actually. It takes a long time to save a species and you also have to consider what do you mean by saving a species, right? So, for my money, a conservation success is when you’ve got a population that is self-sustaining and it doesn’t need us anymore, it doesn’t need me to go and manage it, or my team to go and have a look at what’s going on with it. It’s fine and it’s doing its own thing. So that is always the end game for me.
With the leeches, our idea is to try to establish a few populations – to get more of the species into more places, and spread the risk, to build a more resilient population in the long term.
Thank you. It’s been an absolute pleasure to talk to you!
We would like to thank Dr Helen Taylor for her kindness and consideration in talking to EPOCH about her work as Conservation Programme Manager for the RZSS. We encourage our readers to visit the Royal Zoological Society of Scotland website to learn more about their ongoing conservation work.