MORE than one third of Scotland’s natural features are in an “unfavourable” condition, according to the latest annual figures.

Scottish Natural Heritage (SNH) assessed 5315 habitats, wildlife populations and geological features on protected nature sites around Scotland.

Their report, published yesterday, shows that as of March 31, 34.6 per cent were in an unfavourable condition.

Nearly two-thirds (65.4%) of features were found to have already reached a favourable condition, while an additional 13.3% were found to be on the road to recovery.

Those assessed as either in a favourable condition or in recovery represents a 0.1 percentage point decrease since last year.

Some 19 features have deteriorated to an unfavourable condition since the previous assessment.

SNH describes the diversity of Scotland’s biological and geological natural features as a “particularly rich and valued natural resource”, protected by a series of nature conservation designations.

Dragonflies (100%), marine habitats (98.1%) and earth science (97.4%), which includes geographical outcrops and landforms, fossil beds, and caves, were the categories with the highest proportion of features in favourable or recovering condition, while the biggest increases were noted in vascular plants as well as heath and upland habitats.

The largest decrease was for fish, which were down 4.4 percentage points from 2019. The analysis shows the drop is due to a decline in the abundance of two arctic charr – a species related to salmon – on different sites, the causes of which are being investigated as there appears to be a healthy population of younger fish and no apparent change to their habitat.

The natural features with the lowest proportion in a favourable or recovering condition are marine mammals (57.1%), largely due to a decline in harbour seal numbers; woodlands (64.3%) and birds (67.8%).

For many of the other features in an unfavourable condition – 426 cases – no immediate on-site action can be taken because they are caused by wider, often global pressures.

Declining seabird populations are thought to be related to changes in prey distribution brought about by a combination of factors, including climate change.

Climate change is also believed to be a factor in the decline of a number of natural features on protected areas and poses “a long-term threat” to Scotland’s nature.

Invasive species remain the single biggest reason for features being in unfavourable condition, representing 21% of all negative pressures, followed by overgrazing (17.8%), water management (9%) and recreation/disturbance (8%).

Both invasive species and overgrazing have an impact on Scotland’s woodlands, where herbivores browse and non-native species such as rhododendron, Japanese Knotweed or Himalayan balsam compete with native species for nutrients and light.

SNH is working closely with partners, farmers and landowners across Scotland to take remedial action, including through hundreds of individual management agreements as well as support through the Scotland Rural Development Programme Agri-Environment Climate Scheme.

SNH also leads the four-year partnership Scottish Invasive Species Initiative (SISI) project, which is working to control invasive non-native species along riversides in the north.

Sally Thomas, SNH Director of People and Nature, said: “As we mark the 20th year of our monitoring programme, it’s encouraging to see the progress that has been made over the long-term.

“Despite this there remain significant pressures on our nature sites -- including invasive species, overgrazing and climate change -- and we are working closely with partners, farmers and landowners to help them tackle these challenges and ensure a nature-rich future for Scotland.

“At the same time we will continue to review our programme to equip us for the next 20 years, where we can anticipate more rapid changes to nature in our protected areas, and to guide our response.

“We will do this by ensuring we make the best use of new and developing technology such as remote earth sensing and environmental-DNA analysis to give us the most robust picture possible of the state of Scotland’s nature and better target conservation action.”