Habitat change

Biodiversity rich habitats were lost at an unprecedented rate in the second half of the twentieth century; this was mainly due to more intensive land use and urban development. Since about 1990 the rate of change has slowed and we have begun to reverse these losses for some habitats.

Changes from late 1940s to 1990

Considerable changes took place within Scotland's countryside between the late 1940s and around 1990. Urban expansion, road development and afforestation were among the more striking. Changes in the structure of farmland, or in the extent and condition of moorland may have been less obvious.

Conversion of semi-natural habitats has resulted in the loss of biodiversity and degradation of some ecosystems. Scottish Natural Heritage assessed land cover change in Scotland from 1947 - 1988. The key habitat changes directly affecting biodiversity were: 

• just over half of hedgerows (40,000 kilometres) were lost
• rough grassland decreased by 10%
• heather moorland decreased by 23%
• blanket bog decreased by around 21%, lowland bog by 44%
• semi-natural/ long-established woodland decreased by 28%.

Changes in farmland practices have lead to UK-wide declines in farmland birds, butterflies, bumblebees, and flowering plants. In contrast urban bird populations have increased. Wetlands have been lost to drainage whilst rivers and lochs have been affected by creation of flood defences and dams. (UK National Ecosystem Assessment, 2011  ).

Changes from 1990 to present

Over the last 30 years the rate of habitat change has slowed but the pressure from development and land use change has not gone away.

The 2007 Countryside Survey Results  for Scotland show:

• increase in area of broadleafed woodlands and acid grassland
• 5% loss of hedgerows following previous steady increases
• other semi-natural habitats show no significant change in area.

This slow recovery in semi-natural habitats since the late 1980s has been attributed to the introduction of agri-environment schemes and grants for planting native woodlands.

However, declines in plant species richness and increases in rank vegetation since 1997 indicate that changes in land management continue to have a negative effect on habitat condition. 

Scotland's Biodiversity Indicators shows that farmland breeding birds have increased in abundance whilst butterfly and moth populations have remained stable.