Saving Scotland’s species-rich grasslands

Apithanny Bourne is our guest blogger today. Currently in her third year of a NERC funded Environment Doctoral Training Partnership at Edinburgh University, in conjunction with Scotland’s Rural College, Apithanny is looking at Scotland’s species-rich grasslands and assessing their quality for pollinators using remote sensing. Monitoring floral habitats is a subject well known to Apithanny in her capacity as the Chair of the East Scotland Branch of Butterfly Conservation.

Species-rich grasslands are captivatingly beautiful and rich in biodiversity – there is nothing quite like walking through a buzzing, blooming meadow in June. These special places support a vast array of wildlife and provide essential ecosystem services during a time of climate chaos, as rich grassland soils are one of the most effective carbon stores of any UK habitat. So why have we lost a devastating 98% of our lowland meadows in less than a century? Throughout my PhD, I aim to research Scotland’s remaining fragments of species-rich grassland and the fascinating butterflies relying on them for survival. 

Species-rich grassland on west Coast of Scotland, brimming with Harebell and Eyebrights.

“The British countryside has changed dramatically since the end of the Second World War. Within a single generation, hay meadows that were once an essential part of everyday life, were rapidly replaced by the monoculture pastures now dominating much of our landscape. Many native wildflower species thrive on nutrient-poor soils and alongside sympathetic farming practices, meaning they cannot tolerate today’s intensive use of fertilisers and herbicides. Coupled with the common practice of reseeding grassland with a vigorous fodder crop of Perennial Ryegrass– productivity in modern agriculture has supplanted the traditional hay meadow. 

“This loss of floral habitat from the landscape is undoubtedly one of the driving factors behind pollinator decline in the United Kingdom. A recent report by Butterfly Conservation found 80% of our native butterfly species are in decline, whilst data from the Bumblebee Conservation Trust indicates worrying downward trends for some of our most common and much-loved bumblebee species. Insects and plants typically receive less attention and funding when compared with better-known species and habitats – but these alarming statistics should be a wake-up call. Monitoring the quality of our remaining meadows and recording the pollinators they support is essential for ecosystem health, food security and human wellbeing. Unfortunately, traditional survey techniques are expensive and often require an in-depth knowledge of species identification, accumulated over many years. A lack of expertise in species identification is often a limiting factor when it comes to monitoring insect species and grassland types.

Comparison of (a) Ryegrass “improved” pasture and (b) a restored hay meadow blooming with Yellow Rattle

“I hope to tackle some of these issues during my PhD, which is funded by Scotland’s Rural College (SRUC) and Edinburgh University and aims to promote multidisciplinary research within the School of Geosciences. Whilst performing more traditional botanical surveys and pollinator counts, I have also been collecting high resolution imagery using drones and cameras. By flying a drone above transects in floral habitats, I am able to collect hundreds of images that can be stitched together into a 3D model, in which individual flowers are clearly discernible.

“I aim to use this image database with a technique called object-based classification, to remotely assess the type of grassland habitat and its quality for pollinators. This will work using computer software trained to identify indicator species and hopefully calculate other useful metrics, such as the abundance and percentage cover of flowers. By extracting data from images of floral habitat, I will determine which factors best predict pollinator abundance and richness on the ground. The use of technology in conservation offers great potential as a user-friendly, cost effective and rapid approach to assessment. It could offer efficient long-term monitoring of both protected sites and results-based agri-environment schemes – providing advice on habitat management and allowing quick intervention where sites begin to decline in quality.

Mavic pro drone out in the field.

“For the past two summers, I have been busy collecting data and imagery from some wonderful sites across the Scottish Borders, Midlothian and Fife. The scarcity of meadows has expanded my study area and whilst I absolutely love my field work, I am struck by how small and fragmented these remaining pockets of habitat really are and how difficult it must be for species to move between them. My sites range from degraded hay meadows to botanically rich Sites of Special Scientific Interest (SSSIs), allowing me to record how the pollinator communities change along a gradient of grassland quality. At more diverse sites, I have enjoyed the company of shimmering Dark Green Fritillaries, fairy-like Northern Brown Argus butterflies and bewitching wild plants like the Greater Butterfly Orchid. As you might expect, overgrazed or ‘improved’ grasslands hosted mainly generalist species and in very low abundance. 

A selection of some wonderful species found in rich grasslands.

“Writing this blog post for Scottish Pollinators could not be more apt, as I truly fell in love with species-rich grasslands during a botany internship at NatureScot. Meadows are an important part of our natural and cultural heritage and I firmly believe that everybody should be able to enjoy them – something that keeps me motivated as I begin to analyse my data and prepare my work for publication. We must all work hard to protect and restore ancient pastures, whilst championing the creation of new floral habitat. Let’s hope that technology will help us to achieve this, through locating, assessing and mapping remaining grasslands quicker than ever before.”

Restored meadow with Greater Butterfly Orchid

All photos courtesy and copyright of Apithanny Bourne