Vegetatievoorkeur van de adder op het Hijkerveld

Vegetation preference of Adder in Het Hijkerveld In Het Hijkerveld, a nature reserve of 350 hectares in the northern province of Drenthe, the vegetation consists mainly of Common Heather (Calluna vulgaris), although Purple Moor Grass (Molinea caerulea) dominates in some parts. This reserve is a core site for the Adder (Vipera berus), harbouring at least 1570 individuals. Nature management consists of mowing and sod cutting, as well as grazing with cattle and sheep; volunteers cut young trees. Since 2004, the species composition of the vegetation within a circle of 80 centimeters diameter around each Adder sighted was recorded; no details were given on the height or structure of the vegetation. During the period 2004-2011, 412 visits were made to the area, yielding 5044 sightings of V. berus. In this reserve, 59% of the adders were observerd in vegetation consisting solely of M. caerulea. Vegetation dominated by Common Rus (Juncus effusus) or combinations of M. caerula and C. vulgaris also had many sightings, whereas adders were rarely seen on pure stands of C. vulgaris. The importance of rough parts in heathlands is emphesized; management should aim for this, allowing grasses and rushes to be part of the heathland. In many parts, shrub removal will be sufficient for heathland maintenance. If mowing or sod cutting is deemed necessary, it should be done on a small scale, phased in time and space. Grazing animals should be in low densities, and core reptile areas shielded against grazers.