Description
Cavenham Heath is nationally and internationally important particularly for its plant communities, rare birds and invertebrates. Covering roughly half of the Cavenham & Icklingham Heath Site of Special Scientific Interest (SSSI), it has a range of habitats consisting of a mosaic of heather heath, lichen heath, acid grassland, woodland, riverside meadows and fen. The heath and acid grassland are typical habitats that develop on the sandy acidic soils of the Brecklands .
Habitats
Lowland heath and acid grassland
The heath and acid grassland exists as a mosaic of grassland and heather dominated vegetation. The grassland is dominated by short fescue grasses and sand sedge with lichen heath present in some areas. This mosaic is typical of Breckland heathlands. Within the grassland are typical species such as harebell, common centaury and heath bedstraw.
Broadleaf mixed woodland
Around the edges of the heath, woodland has been allowed to develop and is generally dominated by silver birch. In wetter areas the woodland is made up of downy birch, alder and willow.
Fen meadow and grazing marsh
The floodplain meadows, once isolated from the River Lark, have recently been allowed to flood again which should allow the fen vegetation they support to recover.
Key species
Flora
Over 280 plants have been recorded on this reserve with notable species including: annual knawel, smooth cats ear, hounds tongue, shepherds cress, hoary cinquefoil, mossy stonecrop and suffocated clover.
Lower plants
The site also supports over 100 bryophytes and good numbers of lichens.
Breeding birds
Stone curlews breed annually on the site, which also acts as an important post-breeding roost with sometimes over a hundred birds being present. Good numbers of woodlark are also present and occasionally nightjar and nightingale have been known to hold breeding territories. Other breeding birds of note include: curlew, lapwing, cuckoo, spotted flycatcher and yellowhammer.
Mammals
The rabbit is the keystone mammal on this site, maintaining the short cropped acid grassland turf necessary for many of the other species such as the stone curlew. Otter and water vole are also known to occur along the river.
Reptiles
Good populations of adder, grass snake and common lizard benefit from the mix of dry and wet habitats at Cavenham.
Dance flies
The variety of habitats on the reserve provide conditions for an outstanding diversity of invertebrates.
Flies include the dance fly which has only been found on the banks of the River Lark where they form large, bouncing aerial swarms directly above the surface of the slow-moving river water. Others include rare parasitic flies and a snail killing fly.
Over 20 species of butterfly are recorded annually with important species such as grayling, small heath and white letter hairstreak.
Over 350 species of moth have also been recorded including the rare marbled clover and the lunar yellow underwing. Day flying moths include the forester and emperor moth.
Bats
Eight species of bat frequent the site including barbastelle, noctule and serotine bat.
Further info
Natural England’s Suffolk NNRs:
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