The chalk rivers of Hampshire provide some of our most picturesque landscapes and are nationally and internationally renowned as the historic birth place of dry-fly) angling.

However, it is too often forgotten that this habitat and the fish that swim within it are dependent on a wealth of insects, snails and worms – the invertebrates – that provide food for the fish and maintain the environmental balance of these systems.

To address this, the Hampshire and Isle of Wight Wildlife Trust in partnership with the Environment Agency have launched a new project, the Chalkstream Invertebrates Project, to raise general awareness of the importance of our chalkstream invertebrates and help conserve our most rare species.

Attention will be focused on two threatened species species, the southern damselfly and the white-clawed crayfish.

The southern damselfly is found on the floodplains of the rivers Itchen and Test and is associated with ditch networks of some of the few remaining disused water meadow systems.

Unfortunately, the chalk river populations of southern damselfly are separated from each other by large areas of unsuitable habitat.

The southern damselfly is a weak flyer and this isolation and shortage of suitable habitat makes them a further risk of localised extinction.

Chalkstream Invertebrates Project is working with landowners along the rivers to provide habitats that will act as “stepping-stones” to connect these southern damselfly populations.

Crayfish look like small lobsters. A number of crayfish species are now found in the rivers, lakes, streams and ponds of the UK, but only one, the white-clawed crayfish, is actually native.

Nationally, the white-clawed crayfish is highly threatened due to habitat degradation, pollution, but most significantly the alien signal. The plight of our crayfish in Hampshire is evermore perilous, with only the River Itchen now thought to support white-clawed crayfish in the whole county.

The Chalkstream Invertebrates Project is helping to conserve Hampshire’s native crayfish by working with the Environment Agency, which is undertaking habitat enhancement and creation works to help facilitate the natural expansion of our native crayfish.

Also, by maintaining an up-to-date knowledge of the distribution of American signal crayfish. This is crucial because the signal crayfish out-compete our native species, but the disease “crayfish plague” they carry will eradicate native crayfish populations.

■ If you would like further information about this project and how you may help, or if you have any records or sightings of southern damselfly or crayfish, contact Ben at benr@hwt.org.uk