Wildlife

Ploughing a new furrow

Furrowed crab Xantho hydrophilus Image © Phil Abraham

Dorset Wildlife Trust’s Marine Awareness Officer Julie Hatcher shares the story of work to monitor the recently arrived furrowed crab.

The wildlife-rich shallows and seashore of Kimmeridge Bay were designated as a protected area under UK law in 2019 and form part of the Purbeck Coast Marine Conservation Zone (MCZ). The intertidal zone (the region between the high tide mark and the low tide mark) in Kimmeridge Bay is the only stretch with this level of protection along the open Dorset coast and an important part of our work at the Wild Seas Centre is to record and monitor the marine life along this coastline.

Migrant crabs

One such survey focuses on the furrowed crab, Xantho hydrophilus, a native to the south west coast but a recent arrival in Dorset. Further west, this crab has undergone a population explosion in recent decades, raising concerns about its impact on other long-term residents. First sighted on the seashore at Kimmeridge in 2019, the survey records the population size and any concurrent changes to other crab species on the seashore, including the edible crab, Cancer pagurus, of which there is an abundance of juveniles. Edible crabs move to progressively deeper water as they grow, so the ones found intertidally are the small, immature youngsters. A team of trained volunteers records the number, size and sex of crabs, along with the habitat and associated animals. While the population of furrowed crabs is still at a low level, something interesting has been discovered about the edible crabs; out of the 125 recorded, only four were females. Crab experts appear to have no explanation for this gender discrepancy and further research is needed to solve the mystery.

The need to monitor

Climate change is known to be altering the distribution and survivability of many wildlife species and it is thought that the furrowed crab may be one of these, hence its recent colonisation in Dorset. The effects of shifting distributions and the fortunes of both winners and losers in these changing times are unforeseeable, so monitoring changes and their impacts is vital to our understanding of how we can help. Of course, the most urgent need is to slow the global temperature increase, which will at least give species more time to adapt. Meanwhile our volunteers will continue to monitor this most difficult of ecosystems and share our understanding far and wide.

Devil’s-bit scabious

Growing a wildflower meadow in your back garden isn’t quite as simple as you might think – but it’s important to try, says writer Jane Adams

About ten years ago, I decided to grow a mini wildflower meadow on what was a rather forlorn patch of grass. It was lumpy and weedy, and I could tell it really didn’t want to be a lawn. Actually, allowing it to grow seemed an obvious win. I wouldn’t have to mow it and pollinators like bees and butterflies would benefit from any extra flowers. From what I’d read, insects needed all the help they could get. But I swiftly found out thet proper wildflower meadows are deceptively hard to grow. In that first year I planted chamomile, knapweed, orange hawkbit, bird’s-foot-trefoil, yellow rattle, and devil’s-bit scabious plug-plants to boost the diversity

I thought copying nature would be simple. And it wasn’t.

The common carder bee on devil’s-bit scabious Image: Jane Adams

of plant life. My old lawn buzzed and crawled with insect life, and I felt pretty smug. The following year hardly anything grew except the devil’sbit scabious. I know now what I did wrong. I didn’t research what wildflowers would and should grow in my sandy Dorset patch. I hadn’t considered the rich mosaic of interconnected plants and fungi that were needed to make a lowland meadow - even one as small as mine. In short, I thought copying nature would be simple, and it wasn’t.

A few fragments

In the UK we’ve lost a staggering 97 per cent of our species-rich grassland since the 1930s. That’s equivalent to 7.5 million acres; and quite a few of those acres would have been in Dorset. Over the years meadows were mismanaged, undervalued, and unprotected. What took hundreds, even thousands, of years to grow disappeared almost overnight. But we do still have fragments of flowerrich meadows in our countryside. We just need to join them up so that wildlife can flow from one to another. Which is why conservationists are keen for us to create green corridors for wildlife and plants by growing

wildflowers in our gardens. Just imagine if we could sew a giant living patchwork of native flowers right across We’ve lost a staggering 97 Dorset. In the meantime, the devil’s-bit per cent of our scabious, and the species-rich bees that hang grassland since the 1930s. from their button blooms, are a joy to watch on my old lawn. And they are a reminder we can all do our bit to help wildlife during this ecological crisis.