Introduction
The main habitats you’ll find at Berrow Dunes are fixed dunes, foredunes, and dune slacks and ponds. Foredunes are the first dunes that form, starting above the highest wave line, where only the biggest waves reach during high tides. The line left by the waves, called the strandline, slows down the wind-blown sand so tough, fast-growing plants can start to take root. One of the first plants to grow here is lyme grass, which is tall and grows quickly to keep up with the sand piling up around it. The lyme grass helps form a thin line of low sand dunes. When marram grass grows, it also forms clumps and gets taller if more sand gathers around it, helping build up the dunes even more.
At this stage, these dunes are called ‘yellow’ or ‘white’ dunes because there is a lot of bare sand with few plants. The sand is dry and poor, so only tough plants like sand sedge, sand couch, and sea spurge can live there. Over time, dead plants and rabbit droppings make the sand richer. Moss and lichen start to grow between the plants, and the dunes are then called ‘grey’ dunes.
Marram and lyme grass grow well when new sand is added to the dunes. If the sand stops coming, these grasses die. Too many people walking on the dunes can also hurt the grass, making it easier for the wind to blow the sand away and create gaps called blowouts. The sand that gets blown out will gather further down, and if it is fresh, new marram grass will start to grow there, helping to make the dunes stable again.
Over time, the sand dunes that were once moving near the sea have become still and have new plants growing on them. Now, taller dunes have formed closer to the sea, which stops new sand from reaching the older dunes. These fixed dunes can be about 15 metres high. The grasses that used to grow here, like marram grass and lyme grass, have been replaced by other plants because the soil is now thin and not very rich. On the tops of these dunes, you can see bushes like sea buckthorn, blackthorn, and hawthorn. In the summer, yellow evening primrose flowers are easy to spot across the dunes.
The grasslands on the fixed dunes are mostly covered with red fescue grass and small yellow flowers called lady’s bedstraw. You can also find many other flowering plants here, like restharrow, bird’s-foot trefoil, and different kinds of vetches and clovers. These plants are important food for lots of moths and butterflies, especially in the summer. Common blue and meadow brown butterflies are often seen, along with cinnabar and six-spot burnet moths. There are also many small creatures living here, such as the banded snail.
The grassland on the fixed dunes has lots of short plants and grasses. Because the soil doesn’t have many nutrients, stronger plants can’t grow easily there. Long ago, cows and sheep helped keep the grassland healthy by eating the plants, but they haven’t grazed here for a long time. Now, only rabbits graze in the area, and they play an important role in keeping the grassland in good shape.
One of the main goals for looking after the reserve is to keep lots of different plants growing in the dune grassland. This is getting harder because the soil has more nutrients, like nitrates, which make bigger and stronger plants grow and take over. These nutrients get into the soil from plants such as vetches, clovers, and sea buckthorn, which add nitrogen to the ground. This means that new, taller plants can spread. To help fix this, workers cut back and clear away these fast-growing plants. They also mow the grassland after the flowers have grown and made seeds, just like grazing animals would, to help remove some of the extra nutrients.
Most of the bushes around the grassland are sea buckthorn, with some sallow, elder, and hawthorn mixed in. These bushes give birds places to hide. Birds like blackcaps and cuckoos come here in the summer. Cuckoos lay their eggs in nests built by other birds, such as dunnocks, warblers, and pipits.
In the last hundred years, some new plants have appeared in the area. The most noticeable are evening primroses. They have big yellow flowers that open at night and provide food for moths.
The sand dunes are shaped by the wind and form lines that go north to south, with dips between them. The long, low spots made when new dunes block off part of the beach are called swales, and smaller dips are called slacks. These areas are protected from strong winds and salty spray. They are often damp and may have ponds that last for a short time or all year, because sometimes water is close to the surface. Dead plants and animals build up in these dips, which helps hold the water. This makes it easier for plants and animals that can’t live on the dry tops of the dunes to grow here.
Further away from the sea, the low damp areas between the dunes are home to plants that like wet grasslands, such as different types of grasses, vetches, and iris. In summer, you might spot the pale flowers of broomrape, a plant that feeds off other plants. Many of these plants are food for moth caterpillars. For example, burnet moths lay their eggs on bird’s-foot trefoil and their young build cocoons high in the grass to stay safe. Cinnabar moth caterpillars, which are orange and black, eat ragwort.
All these plants and insects attract lots of birds, including skylarks, yellowhammers, and magpies. Skylarks often nest in the grass and are easier to hear than to see. In autumn and winter, birds like linnets, bramblings, and chaffinches visit the area, but they nest in the north during summer. You might also see short-eared owls hunting for small animals in the dunes.
There are a number of ponds in the reserve. Some dry up at times, while others stay wet all year round. These ponds are home to many wetland plants, like common reedmace, narrow-leaved reedmace, marsh pennywort, gypsywort, meadowsweet, and water mint. Lots of different insects live in these wet places, including 14 kinds of dragonfly, such as the hairy dragonfly and the ruddy darter. Many beetles are found here too, including the rare greater silver diving beetle. The ponds also have great crested newts, which are a protected species and breed in these waters
Lots of insects live in the sallow bushes nearby. These bushes give them food and shelter. Some, like the buff-tip moth and lackey moth, lay eggs there and their caterpillars leave silky threads. Greenfly also feed on sallow, which brings in many birds that eat bugs. There are also two special kinds of soldier flies living here that are very rare in the country.