The Royal Society of Edinburgh

RSE@ Inverness Outreach Programme

Public Talks

Ask the Experts: Scotland’s Biodiversity

2 June 2018, Eden Court, Inverness

Reports: Kate Kennedy

Professor Colin Moffat, Marine Scotland Above and Below: The Mysteries of our Seas Scotland’s seas cover an area six times that of our landmass. Furthermore, 70% of the planet is covered by salty water. Thus, our seas and oceans are vital to life on Earth, transporting heat, nutrients and energy around the globe and having a major impact on our and the production of the oxygen we require; 40–50% of the Earth’s oxygen comes from the phytoplankton in our oceans. The biodiversity of the seas is phenomenal. Professor Moffat explained that we do not have to travel to far-flung destinations such as Australia to experience the vast array of colour and diversity in the ocean; it can be found all around the UK. Indeed, Scotland has very productive seas. Warm water travels across the Atlantic, up the west coast of the UK and into the . This water is warmer and saltier than the water in the North Sea and brings with it the nutrients that are the basis of our food chain, meaning the waters around Scotland are some of the most productive in the world, with plentiful supplies of cod, haddock, mackerel and herring. A range of species from the bottom of the food web right through to the top can be found a few off the Scottish coastline. Even the deepest parts of the ocean, for example the Rockall Trough at c.3,500 metres deep, contains a variety of marine life. Our seas provide food for the many plants and animals found in the water, from small to large. Phytoplankton are extremely small, some 15 times smaller than the width of a human hair. Whereas the blue whale, the biggest creature on Earth, can weigh 200 tonnes, similar to the weight of 40 elephants, and has a heart the size of a Mini car, which beats eight times per minute and can be heard two away. Professor Moffat explained that all these marine species are interlinked and are part of the web of life found in the seas. Phytoplankton are eaten by zooplankton, which in turn are eaten by young fish and shellfish, which are then eaten by larger fish, which themselves are consumed by larger predators, such as seals. If any part of this chain is disrupted, it has effects both further up and down the chain. Thus, top predators, such as seals and even humans, can be affected by what happens to our smallest species; it is incredibly important that we are very careful about our impacts on all marine life, including the phytoplankton. Recent television programmes such as Sir ’s Blue Planet II, which attracted huge viewing figures, have brought the issues surrounding plastics and pollution contaminating our seas into the public eye. Professor Moffat gave examples of risks to our seas and their biodiversity, highlighting that every time we flush the toilet or wash our dishes with detergent, we risk putting chemicals into our seas. Indeed, one chemical that was banned from production in the previous century can still be found in significant concentrations in the seas. Human use of plastics is also affecting our biodiversity, causing both entanglement and issues due to animals ingesting them. Recent research at a monitoring site off Stonehaven, northeast Scotland, revealed that, when filtered, five cubic

1 metres of surface sea water contained 42 micro particles of plastic and 93 fibres. Contaminants and plastics have even been found in fish living in seas 1,000 metres deep and in sediments even deeper. If we want to retain the magnificent biodiversity in our seas, it is vital that the human race changes how it lives and considers carefully how it uses products which can impact on our marine ecosytems. Professor Moffat also commented on some of the extremities of our oceans. Some of the largest fish in the world, such as the basking sharks, can be found in Scottish waters, while the giant squid is found in the northeast Atlantic. The whale shark, which can measure up to 20m long, is found in more temperate and tropical waters. However, the connectivity of our seas means that we have occasional visitors to our waters; it is not impossible to encounter a great white shark. We also have some extremely old species in our seas; the ocean quahog can live for about 500 years and can be aged by counting its shell rings, similar to tree rings. The seas surrounding Scotland and the rest of the UK are also very deep in areas; up to 2,500m and exerting a pressure of 3,659 pounds per square inch in their deepest areas. The sea temperatures vary depending on both depth and latitude. Around Scotland, our surface waters are relatively warm at 12°–13°C. However, Arctic surface waters and Arctic deep waters can be slightly below 0°C, while other deep waters are often in the range 0°–3°C. The biodiversity in our seas is also of interest to industry, for example, the presence of a certain type of clam often indicates areas of the seas which leak natural hydrocarbons, which is indicative of the presence of oil. Marine research is of vital importance in maintaining and improving our marine environment. Professor Moffat’s research boat is a treasured, but expensive, asset, but this and tools such as autonomous boats (including ‘Boaty McBoatface’ aka RRS Sir David Attenborough) are vital to the exploration of our seas. The marine environment is incredible, with some of the biggest and smallest creatures in existence, but they are all currently being affected by human activity which is threatening the circle of life. Should we wish to retain our environment, it is vital that humans change their lifestyles and particularly use of plastics and pollutants, immediately.

Dr Keri Langridge, Scottish Wildcat Action What is a Scottish wildcat and are there any left? There are many different types of wildcat, spread all over the world. The Scottish wildcat is descended from the European wildcat, a forest cat that lives in the cold regions of Europe. Pet or domestic cats are descended from the North African wildcat, which is a desert cat. However, there are many species and sub species of cat and all can interbreed. The Scottish wildcat is a forest cat and has a big, thick coat and likes to live in a habitat with both forest cover and grassy areas in which to hunt. Their diet mainly consists of rabbit, voles and mice. They live in dens, for example at the base of trees, and in brash and rocky piles. Their breeding season takes place over the winter, with kittens born around April/May. In common with domestic and other wild cats, they like to follow linear features in their environment, such as walls, hedges and rivers. The Scottish wildcat used to be widespread in Britain’s forested areas and has been in the country for about 9–10,000 years, since the last Ice Age. The Scottish wildcat is in decline. In 1800, there were wildcats existing in Scotland, Northern England and Wales. They had already been exterminated from the rest of England; people saw them as vermin, wanted their fur and their forest habitat was being reduced. By 1915, there were no wildcats remaining in England, Wales and southern Scotland and only a limited population in the far north of Scotland. The onset of World War 1 helped save the Scottish wildcat from extinction at this time. Scottish estates were closed due to working men being away at war; this offered a reprieve from hunting and the wildcat population managed to expand. Furthermore, the creation of the Forestry Commission saw the of large areas in the north of Scotland, thus creating new habitat for the wildcat. However, it became apparent that many

2 of the pure wildcats were breeding with domestic and feral cats, causing hybridisation of the species. Over time, the Scottish wildcat breed has become diluted and it is questionable as to whether there are now any pure Scottish wildcats in existence in the wild, indeed it is thought that all Scottish wildcats are now hybrids. Today, there continues to be some persecution of the wildcat and they are also at risk of disease from pet cats and being killed on the roads. They are a critically endangered species and when last measured in 2016, the population was estimated to be between 100 and 300 wildcats living in the wild. Scottish Wildcat Action is a partnership project that delivers the Scottish Wildcat Action Plan. In recent years it has been determined that the only way to save them from extinction is for various interested groups to work together to try and reduce threats to the wildcats. Conservation specialists also run a breeding programme, as a safety net and this has resulted in a good captive population. Scottish Wildcat Action monitor various regions in the North of Scotland to ascertain where the wildcats are living and determine where best to target their conservation work. They also deliver a track, neuter, vaccinate and release (TNVR) programme for feral cats. They also promote responsible domestic cat ownership, train people in wildcat-friendly predator control and habitat management and take part in education and awareness raising. Due to limited resources, Scottish Wildcat Action cannot cover the whole of the north of Scotland, so they work in target areas – areas of good habitat, but also on estates that want to be involved and where there has also been recent evidence of cats in the region. Some regions have been dropped from the programme due to no evidence of cats in the region. When a Scottish wildcat is captured, either in a trap or in a photograph, it is assessed against criteria to ascertain if it is a wildcat, a hybrid or a domestic cat. The criteria relate to the morphology of the creature – how it looks – and its behaviour. There are seven features to assess: whether the dark line runs down the back of the animal to the base of the tail – domestic cats have lines that continue down the tail; whether the tail is blunt, bushy and fat – domestic cats have thin tails; whether the animal has stripes or rings, like a lemur, that are thick, black and separate – wildcats should not have spots; if it has four thick, black, wavy lines on top of the head; and if it has two stripes on the shoulder. Each of these features are scored out of three: three for a wildcat feature, two for a hybrid feature and one for domestic cat feature. A pure Scottish wildcat would reach a maximum score of twenty-one. There are no wildcats that score this highly anymore, the cut-off point to determine that an animal is a wildcat has been set at seventeen and anything scoring below this is considered a domestic or hybrid cat. Recent research in Strathspey identified only one cat scoring over seventeen and sadly, this one had to be euthanised due it being affected by feline HIV. There was a similar picture in all of the other sites surveyed. Dr Langridge concluded that the Scottish wildcat is now in a situation where it might be functionally extinct in the wild as there is not a large enough number for breeding. There are over seventy wildcats in captivity, so all is not lost. All the captive wildcats score highly on the assessment criteria. It may be that conservation breeding for release is the next step, but this is a long-term plan.

Mr Tom Prescott, Butterfly Conservation An Introduction to Moths and Mothing In Scotland, we have 36 different species of butterfly and 1300 different types of moth. However, despite moths frequently getting ‘bad press’, they often have the more interesting names; for example, tigers and sharks. Moths live in diverse habitats, including roots on the shoreline, underwater and on the tops of our highest mountains. Some moths living in very cold environments remain in caterpillar form for up to four years. Most feed on leaves, stems and roots and some caterpillars feed on lichens, mosses and decaying matter such as birds’ nests. Indeed, nearly every habitat has associated moths. Some moths are very fussy, with some caterpillars choosing to feed only on one specific plant. Thus, some species are very rare, as they have such a narrow habitat. An example of this is the New Forest burnet, which

3 is only found on a remote part of the Scottish coastline. This moth is also an example of a species that was under threat but has been successfully conserved. Sheep were eating the plants the moths liked to eat, resulting in only about 12 moths remaining in existence. Active conservation of the area through managing the habitat and removing the sheep helped the population grow to about 12,000 within 9 to 10 years. This is proof that species can bounce back, given the right conditions. Butterflies and moths are all part of the same Lepidoptera family. There are no major differences between butterflies and moths. Indeed, contrary to popular belief, many moths also only fly during the daytime, not just at night. Many people believe moths to be dull, brown and boring and some are. However, the vast majority are very colourful. Indeed, the elephant hawk moth that lives on rosebay willowherb has a beautiful pink body. Mr Prescott described how he regularly uses simple methods to study the moths in his own garden. Over recent years, he has identified around 12 species of butterfly in his garden, but over 300 types of moth. The general public generally have no idea about the number and type of moths living in their gardens, but using simple equipment, they can become more accessible. Even in small gardens, it is possible to grow plants that are attractive to butterflies and moths. Placing bedsheets underneath trees and bushes in the evening and then shaking them results in the butterflies and moths dropping onto the sheets, making it easier to observe the different species. It is also possible to make a nectar substitute of dark beer, brown sugar and treacle and painting this on the fence posts to attract moths. Wine roping is another simple method, by which pieces of string soaked with a nectar substitute are hung outside to attract the moths. However, there is no substitute for natural nectar during the summer months, when the moths will be attracted to natural plant life. Most people, however, catch and study moths using moth traps. The blue light and heat attracts them. Mr Prescott commented that he recently caught 80 moths of about 20 species in Glen Nevis using this method. However, in towns and cities this method is not as successful, due to too much light pollution from street lights. Moths are also less common on cold evenings. An ideal mothing night is muggy, still and calm. The most moths ever caught by Mr Prescott was 1800 moths of 70 different species and the most species he has ever caught on one evening is 140. A moth trap has holes at the bottom and doesn’t harm the moth. The number and species are counted and recorded and then the moths are released. Birds and bats are predatory to moths and whilst bats and some birds are protected species, there is only one protected species of moth. Additionally, some parasitic flies are a risk to moths when they lay their eggs in the caterpillar and flies emerge from the pupa rather than a butterfly or moth. It is still unknown why moths wait until it is dark to fly and then head for the brightest light. There are various different theories relating to the Moon as a navigational tool, but nobody really knows why night-time insects are attracted to bright lights which then disorientate them.

Dr Max Coleman, Royal Botanic Garden Edinburgh Location, Location, Location: Making Homes for Wildlife In 2007, Dr Ken Thompson published a book entitle No Nettles Required which explained how, through small monitored interventions, urban, ordinary gardens can become vital to Britain’s biodiversity in terms of attracting wildlife. This evidence-based research reminded people that, like countryside management, gardens are also extremely important. Why is it that urban gardens are important and why is the countryside getting less valuable for wildlife? In Britain, we know a lot about how land is being used and various studies break down land use into lots of categories. Looking at these studies, it becomes apparent that urban sprawl is not as bad as we might at first think. Britain is not an urban country, in fact only about 5% of the country is urban and within that there is a lot of green space. Intensive agriculture, particularly in arable areas, is causing habitat loss and, in turn, loss of wildlife.

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Potentially unfriendly environments for wildlife are created through the heavy use of chemicals to remove weeds growing alongside crops, and through the removal of hedgerows and copses to streamline the agricultural process for maximum efficiency. This doesn’t happen all over the UK, and not in all agriculture forms, and we must not forget that agriculture also has a vital role to play in the UK in terms of feeding the growing global population. However, we do need to accept the damage it is potentially causing to our biodiversity and address the problem. We can do things in our own gardens to help counteract this and create a positive impact. Often, the general public think of their gardens as ‘our small patch of land’ which finishes at our property boundary and thus, probably cannot have an impact on the wider environment. This is not correct. We need to realise that our own gardens are a small part of a network of more gardens, all being managed differently and thus, creating diversity. Differing types of gardens create ideal environments for many species; for example, decking gardens might be where hedgehogs nest and thick hedges are potential homes for birds and bees. It is often thought that only native plants have value in our gardens. However, bumblebees are an example of how non-native plants can also be valuable to wildlife. Dr Coleman commented that you just have to look at plants in garden centres to see that bees are attracted to a variety of plants, not just the native ones. Bees visit all plants that provide their needs and the key to a good bee habitat is diverse planting, providing a variation in pollen. It is not necessary to plant nettles and other weeds and native plants in our gardens to create an environment for biodiversity. In fact, for most people, successful wildlife gardening is a case of carry on what you are currently doing and building in some small interventions to assist with biodiversity. It is most important to create the garden that suits you and this will be adding to the network of diversity. When we consider attracting wildlife to our gardens, we are generally thinking about larger, more charismatic animals. However, this might not be the most appropriate goal. Hedgehogs, for example, are in decline and roam over big areas and therefore, could be transient in your garden. Waxwings are transient visitors in the wintertime from Scandinavia and take advantage of berries. Therefore, whilst we can plant things that are attractive to particular species, the chance of actually seeing them is quite small. It is perhaps better to manage expectations and think about the smaller species. If we consider life as a pyramid, the base of which would be the really small things that rule the world – bacteria, fungi and microorganisms – things we need to do important jobs and exist in large numbers, regulating the environment. These are difficult to see with the naked eye and are the least well-known species in the pyramid of life. However, most people do not want to invest in expensive microscopes to research these species in their gardens. The next level would be animals and insects that are still small but able to be appreciated with the naked eye; for example, bees and other invertebrates. Thus, by attracting such organisms, it is possible to observe things in your garden that you’ve never noticed before, do some research and learn some interesting facts about biology. Dr Coleman detailed two simple projects which help attract bees to your garden. The first is to drill holes in a log to attract solitary bees. There are 250 bee species in Britain, only one of which produces honey. The vast majority of these bee species are solitary and find a suitable cavity which they provision with pollen ready for a young bee. They lay an egg and then find another cavity and do the same. It is possible to observe these in your garden; for example, leafcutter bees putting leaf remnants at the entrance of the cavity to seal it and mason bees collecting mud and building barriers at entrance of the cavity. These log houses are generally better than commercially produced bee houses, which are often not very well designed. If placed in the sunniest part of the garden in a raised area, there is a high chance of getting two or three species of solitary bees colonising the log house. It is also possible to create a lightweight version of a log house using paper straws and sealing off one end. A second option to attract bumblebees is, in February/March, place a small plant pot fully into a hole in the garden and line this with some dry moss, placing a tile or something flat on

5 top of it to create a lid, leaving a small hole for the queen to access. Bumblebees live in small colonies of about 50–100 individuals. In the Spring, the queen finds a suitable cavity, lays eggs and provisions the space with pollen. Worker bees then take over the project and the queen concentrates on egg-laying. Over the summer the colony grows. Placing the plant pot in the garden may attract the queen bee and thus producing a colony of bees to study and watch. Again, commercial, expensive boxes are notoriously unsuccessful for this process. There is a good chance that bumblebees may already be nesting in areas of the garden and it is a case of patiently watching from where the active bees are coming to pinpoint where nests might be.

A Vote of Thanks was offered by Professor Michael Usher FRSE.

Opinions expressed here do not necessarily represent the views of the RSE, nor of its Fellows The Royal Society of Edinburgh, Scotland’s National Academy, is Scottish Charity No. SC000470

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