The entirety of Box Hill lies within the Surrey Hills Area of Outstanding Natural Beauty. The vast majority of the publicly accessible areas of the hill that are managed by the National Trust and Surrey Wildlife Trust, form part of the Mole Gap to Reigate Escarpment Site of Special Scientific Interest and have been designated a Special Area of Conservation.

The chalk downland of Box Hill provides a habitat for a wide range of plant species, which in turn support a varied population of insect species. The alkaline soils are thin and nutrient poor, which prevents deeper-rooted lush grasses from dominating. Each square metre of chalk downland may support up to 40 different species.

Without careful management, the grassland would revert to woodland and so these areas of the hill are grazed in order to prevent scrub from becoming over-established. Both the National Trust and Surrey Wildlife Trust use Belted Galloway cattle which crop the grass less hard than other grazers and allow the more delicate wild flowers (including orchids) to flourish. At Betchworth Quarry, Surrey Wildlife Trust allows goats to graze, which can eat woodier plants such as gorse and bramble. Rabbits also make a significant contribution to the control of scrub and coarse grasses on the hill, although their numbers have declined since the introduction of myxomatosis in 1953.

 

Biodiversity

The chalk downland environment supports notable populations of bats, lepidopterans, orchids and the hill's namesake, the box tree (Buxus sempervirens).

 

Orchids

A large number of species of orchid have been recorded on Box Hill, including autumn lady's-tresses, bee orchids, bird's-nest orchids, broad-leaved helleborines, common spotted orchids, early purple orchids, common twayblades, fragrant orchids, pyramidal orchids, frog orchids, musk orchids, man orchids, butterfly orchids, fly orchids, and violet and white helleborines.

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Other wild flowers

Wild garlic grows alongside bluebells under the tree canopy beside the River Mole at the western edge of the hill, giving the area its distinctive smell in springtime.

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Aquatic plants

Damasonium alisma (starfruit) was reintroduced to Headley Heath in 2013 using seeds from the Millennium Seed Bank, having been absent since 2000. It is now found in Brimmer Pond (half of which is enclosed to prevent habitat disturbance by dogs) and also in Heath House Pond.

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Trees

The box and yew woodland, on the steep-sloping sides of the hill above the River Mole, is of international importance. Common canopy-layer species include beech, ash and oak. Understorey species include holly, hazel, elder and honeysuckle.

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Invasive species found on the hill include buddleia, cherry laurel, Japanese knot weed and Canadian goldenrod. Boxwood blight, a fungal disease caused by Cylindrocladium buxicola, is widespread.

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Bats

Several abandoned brick and concrete structures provide habitats for bats and grills have been placed over their entrances to protect the roosting sites. Three species are known to inhabit the old Box Hill Fort: the brown long-eared bat, the noctule bat and Natterer's bat. The brown long-eared bat, Natterer's bat, the whiskered bat and Daubenton's bat have been recorded at both Betchworth and Brockham quarries. Brandt's bat has been recorded at Betchworth; Bechstein's bat and the common pipistrelle have been recorded at Brockham.

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Butterflies and Moths

Box Hill supports 38 different species of butterfly. Species include silver-spotted skipper, dark-green fritillary, grizzled skipper, dingy skipper, adonis blue and chalkhill blue (grassland); brown hairstreak (scrub); purple emperor and white admiral (woodland). The small pearl-bordered fritillary was present on the hill in the 1970s, but has not been recorded locally since 1997. Kidney vetch, growing in the Zig Zag Valley and below the Viewpoint, supports populations of the small blue. To create new habitats for the butterflies, a number of ‘scrapes’ were excavated in the late 2010s, exposing bare chalk on which vetch can become established with minimal competition. Buddleia removal was also initiated as part of the same programme.

 

Rare moth species found on the hill include the straw belle, chalk carpet, lace border, orange-tailed clearwing and the Surrey midget moth.

 

Others

The hill has given its name to a species of squash bug, now found throughout south-east England. The introduced edible Roman Snail is common also.