Towards the end of July, I visited the Maer, a nature reserve situated at the eastern end of the promenade in Exmouth. With its sand dunes and sandy grassland, the Maer is a remnant of a much larger dune system that once stretched down to the beach. Nowadays, it provides an oasis of calm close to the busy seafront as well as a habitat for special plants and insects.
A slight mist softened the long views as I walked eastwards along Exmouth seafront. Some warmth penetrated the cloud and a few people were already enjoying the beach on this late summer morning. The sandy tip of Dawlish Warren lay tantalisingly close across the water and further on, the Ness at Shaldon lurked in the mist like a gigantic wedge of cheese. The commercial area with its big wheel, pubs and cafes was busy but eventually I reached a quieter part where sand and scrub tumbled downwards at the side of the beach road. This is the edge of the Maer, a local nature reserve and one of Exmouth’s hidden gems. Superficially, the Maer is a large grassy, sandy space sandwiched between the beach road and Exmouth Cricket Club but it conceals a mosaic of different environments with unusual flora and fauna.
A substantial sandy dune ridge forms the southern border of the Maer giving views across the reserve on one side and towards the beach on the other. Marram grass grows thickly giving the sand stability but there are also areas of bare sand and areas of scrub, reminders of the dune system that must have occupied this area before the beach road was built. Restharrow with its pink and white pea-type flowers and a few residual yellow evening primrose provided some colour but it was the sea holly that surprised. This is an unusual and unexpected plant that grows extensively along the first part of the ridge. Its spiky greenish-grey leaves with white margins and veins and its powder-blue flowers light up the sand as though someone had spilt pale paint. Sea holly flourishes in these arid conditions by having leaves covered in a waxy cuticle to help retain water and through its deep roots. Although sea holly has some visual resemblance to our Christmas greenery, it is a relative of the carrot; in the past it was employed as an aphrodisiac.
Several large insects with bold black and yellow markings crawled about the bright blue sea holly flowers collecting nectar. These are beewolves, some of our most spectacular solitary wasps, that nest in sandy places and specialise in catching honeybees. Both male and female beewolves were feeding that day but it is the larger female (up to about 2cm long) that catches and paralyses honeybees and may be seen flying back to the nest carrying a quiescent honeybee beneath her. She digs a nest tunnel in sandy soil up to a metre long with multiple terminal branches where she lays eggs and provides honeybees as food for the developing larvae. These once rare insects have expanded their UK range since the 1980s, possibly in response to climate change and I saw them in several places on the reserve notably on a stand of mauve thistles. They are not aggressive towards humans.
Further along the ridge, before it is colonised by brambles, scrub and low trees, I found a large clump of an unruly scrambling plant covered in pea-type flowers of an impressive reddish-pink colour. This is broad-leaved everlasting pea, a perennial relative of our annual sweet pea, growing through the grasses on the Maer ridge holding on via thin tendrils. A chunky dark bee was feeding from the flowers, apparently undeterred by their jerky movements in the breeze. This was a leafcutter bee, most likely the Coast Leafcutter Bee that favours sandy habitats near the sea. They nest in burrows in vegetated sand lined with pieces of leaf cut from trees and plants. Later, when the sun came out, I saw several of these bees chasing one another around the bright pink flowers like children in a playground.
The large central part of the reserve was coated with golden brown grass criss-crossed with paths for walkers and looking very dry, a reflection of the recent lack of rain. Within the grass were mats of restharrow and many of the yellow dandelion-like flowers of catsear. One area resembled a lunar landscape with many small craters where the surface had been dug out exposing the sand. Solitary wasps and small leafcutter bees had happily nested here.
Tall clumps of ragwort with bright yellow daisy-like flowers and deeply lobed green leaves were dotted around the central area. This plant provides valuable habitat and food for invertebrates and I found one clump that had been appropriated by black caterpillars with prominent yellow bands. They were moving about, eating the leaves of the ragwort, voraciously consuming the greenery and destroying the upper parts of the plant. These are caterpillars of the cinnabar moth and as they feed, they assimilate some of the toxic alkaloids contained in ragwort, rendering themselves unpalatable to birds and other predators. It is said that their yellow stripes act as a warning to birds. Once fed and mature, the caterpillars dig themselves into the ground to spend 12 months or so as pupae before emerging as beautiful day-flying red and black moths. The adult moths live for a few weeks, feeding on nectar before mating and laying eggs on the ragwort leaves. The eggs grow into caterpillars and the cycle starts all over again. The cinnabar moth is entirely dependent on ragwort for its survival.
Towards the western end of the reserve, I found a large colony of flowering plants, perhaps suggesting damper conditions. Clumps of common mallow up to a metre tall dominated with their trumpet flowers composed of five deep pink petals each with purple stripes. At the centre of each flower was a mass of grey pollen-covered stamens emanating from a single stalk like a miniature bunch of flowers. Near the mallow, large areas were covered by a sprawling, scrambling plant richly covered with pea-like flowers above many small, spear-shaped, mid-green leaves. Flower colours varied from very pale to light blue, mauve and deep purple with some plants having several of these colour variants. One plant even had bright yellow flowers. This is Sand Lucerne, a fertile hybrid of lucerne and sickle medic, naturalised in East Anglia, where its two parents grow together, but now transplanted elsewhere.
There’s so much to see at the Maer and I could easily have spent several more hours looking about. But I had a train to catch so I headed back along the promenade and across the town towards the station.
Philip Strange is Emeritus Professor of Pharmacology at the University of Reading. He writes about science and about nature with a particular focus on how science fits in to society. His work may be read at http://philipstrange.wordpress.com/
