Table 2. Declines and losses of different species groups in the New Forest believed to have occurred within the past 150 years, and associated causes (threats). Based on information presented in Newton (2010 a,b), synthesized from a number of sources.

Species group Trends Threats
Birds At least three species lost during the last century. While some species (such as nightjar- Caprimulgus europaeus and woodlark- Lullula arborea) are stable or increasing, others (such as Dartford warbler- Sylvia undata, snipe- Gallinago gallinago, curlew- Numenius arquata, and redshank- Tringa totanus) are declining. Species losses attributable to habitat loss and possibly climate change. Causes for declines in species often unclear, but may include inappropriate habitat management (e.g., Dartford warbler- Sylvia undata, sparrowhawk- Accipiter nisus), disturbance from human recreation (e.g., ground-nesting birds), climate change, and nest predation (e.g., Montagu’s harrier- Circus pygargus).
Mammals Red squirrel (Sciurus vulgaris) was extirpated in the 20th century. No evidence of species losses in other mammalian groups. Insufficient data to determine trends in threatened species (e.g. bats). Red squirrel was previously hunted as vermin (Lovegrove 2007), but was extirpated by 1947 (Tubbs 1968), through competition with, and disease from introduced grey squirrels (Sciurus carolinensis) (Natural England 2010). Some forest management interventions may be negative (e.g., tree felling and holly pollarding) for bat species. Possible disturbance from recreation.
Reptiles and amphibians One extirpation of a native species (Natterjack toad- Epidalea calamita). Sand lizard (Lacerta agilis) lost by 1980s, but reintroduced. Common toad declines may be caused by fungal disease. Inappropriate heathland management (burning) responsible for loss of sand lizard (Lacerta agilis). Main threat to reptiles is inappropriate heathland management (e.g., burning).
Fish No evidence of losses. Insufficient data to determine trends. History of catchment modification and drainage likely to have had negative impacts on fish populations, but evidence limited. Current management interventions, including woody debris accumulation in streams and physical modifications to stream channels, can have both positive and negative effects.
Dragonflies and damselflies One extirpation. Some evidence of historic declines in some species; others appear stable. Drainage actions and scrub development responsible for species loss.
Saproxylic beetles At least five species believed to be extirpated; 27 further species not reported in past 25 years. Insufficient data to determine trends, although some species appear to have declined. Extirpation caused by scrub clearance, and forestry/ commoning activities involving the felling of large, old trees.
Butterflies and moths General decline of many species in recent decades; 124 species believed to have been lost. Increased levels of herbivore grazing and browsing, particularly in the Inclosures, leading to a loss of structural diversity and food availability. Greater intensity of management for grazing (burning, reseeding, scrub clearance). Direct destruction of habitat caused by forestry operations (e.g., conifer planting, management of rides). Economic pressures driving land use at the Forest margins (e.g., urban development, pony paddocks, lack of support for traditional woodland management).
Other invertebrates Insufficient data to determine trends. Some extirpations are likely to have occurred as many rare species have not been recorded for a long time, e.g., New Forest cicada may now be extirpated. Groups such as Orthoptera appear to have undergone significant declines. Changes to the grazing regime and management of the heaths and woodlands are likely to have had a detrimental effect on many insect species and their habitats. Increase in grazing intensity since the 1960s is a particular issue, especially in Inclosures. The intensification of farmsteads within the Forest and the loss of small rotationally managed fields must also have had a negative effect on the Forest, as throughout the wider countryside. Inappropriate ride management and widespread scrub clearance likely to have negative impacts.
Vascular plants One species known to have been extirpated in the middle of the 20th century: summer lady's-tresses (Spiranthes aestivalis), which was exterminated by over-collecting and habitat drainage. Little evidence of declines in species, although few monitoring data available and impacts of human activity uncertain. Invasion by exotic water plants (e.g., Crassula helmsii) is probably a major threat to flora associated with ponds. Other invasive species such as Rhododendron similarly pose a threat to terrestrial vegetation. In the 20th century, forestry practices involving creation of new plantations and conifer establishment in ancient woodland undoubtedly caused enormous damage. Management practices encouraging grazing within the Inclosures during the second half of the 20th century led to negative impacts on flowering plants.
Lichens Few monitoring data available. Most uncommon species appear to be stable. However, some are clearly declining and some extirpations appear to have occurred. A total of 13 species were recorded from New Forest woods in the 19th century and have not yet been refound, and may therefore be extirpated. In addition, four leafy species recorded since 1967 appear to have been lost and a further four are declining and rare. The spread of holly (Ilex aquifolium), and hence increased shade, in the past 150 years is the most significant issue. Pollution is another significant factor, especially of sulphur and nitrogen. This may be responsible for difficulties in colonizing rather than direct poisoning of the mature thalli. Death of trees has also caused loss of colonies.
Fungi Few monitoring data available. Little evidence of declines. Extirpations hard to evaluate although 18 species of conservation concern have not been seen in the past 50 years and may be extirpated. Substantial losses of semi-natural woodland through felling and establishment of exotic conifers in the 20th century must have had a major deleterious impact on fungi. Other threats include deadwood removal, and possibly also commercial collecting and climate change.
Bryophytes Four species of liverwort have apparently been extirpated. Most species generally stable. Some species threatened by scrub invasion.