By Glenn Norris, Reserves Ecologist
Lowland heath is one of the rarest habitats in the world, and Britain holds 20% of that total. Its rarity immediately make this habitat incredibly important to retain but also as it is host to a number of habitat specialists only found on heathlands.
Sussex Wildlife Trust manages a lot of heathland within Sussex and each has its own characteristics. Stedham and Iping Common is a typical lowland heath, dominated by Heather in the dry bits and Purple Moor-grass in the wet bits. Welch’s Common on our Burton Pond reserve is a grassy heath where Wavy Hair-grass and Sheep’s Sorrel dominates, perfect habitat for the incredibly rare Field Cricket. Levin Down is chalk downland, but with small patches of acid soils left during the most recent Ice Age creating Chalk Heath, where plants of acid and chalk soils grow side-by-side.
Ten years ago Graffham Common was swamped in conifer plantation, but after considerable effort from the Trust in clearing the woodland, exhibits one of the best spider communities in Sussex. And finally Old Lodge, forming part of the Ashdown Forest sits at 200m above sea level (compared to the 50m at Iping Common) and therefore is often considerably colder making it excellent for species with a typically north-western distribution.
I love these heathland sites because whenever I go, I find something I’ve never seen before. This is down to the mosaic of habitat structure which the Trust works so hard to create. A simple rule of thumb is that where vegetation structure is diverse, the invertebrate fauna will be too.
One of the rarest and most important structures is bare ground. This is the hottest part of the heath and so some of our rarest species live there like the Heath Tiger Beetle. The Trust creates these areas by using excavators to scrape away the top layer of soil and everything above it. In ten years’ time, the heather will have grown so much that it is almost invisible, which is why scrapes are added each year.
Heath Tiger Beetle
As well as scraping and mowing, controlled burning of small tennis court-sized plots of dry heath is also an important management technique for creating a habitat mosaic, creating bare ground and regenerating heather. This is only done between November and February when no damage will be done to reptiles or breeding birds and is carefully monitored by highly trained staff members. This technique is important because it reduces the risk of accidental fire during the summer, but also burns up the litter layer to prevent nutrient loading in the soil.
In addition, there are some species that rely on fires to create the habitat they need including money spiders recently found on Iping Common. That being said, accidental fires caused by barbecues or bonfires during the summer can be catastrophic to lowland heath as they can quickly grow out of control posing a danger to wildlife, livestock and people.
Heathlands have developed due to constant human intervention and will continue to be managed in that way by the Sussex Wildlife Trust using a range of techniques so that the rare plants and animals can thrive in these globally threatened habitats. Take a look at your nearest heathland this weekend and see if you can see the different habitat structures present through these management techniques.