THEY are our little green islands, the vital but vulnerable corners of the country set aside for nature. And they are doing all right.

In rare good news for the environment, the latest figures suggest that nearly eight out 10 of Scotland’s most protected areas are now either in favourable or recovering condition.

Environmental watchdogs are far from complacent and warn that invasive species - aliens such as rhododendrons or Japanese knotweed - post the biggest threats to fragile ecosystems.

Scottish Natural Heritage, which came up to the number, was talking about more than 5,000 “features”, such as individual habitats, species and earth sciences such as fossil beds and caves, on around 1800 protected nature sites

It said 78.9% of them were good or getting better. a drop of 0.8 percentage points since last year but is up 2.9 percentage points from 2007.

Only around two-thirds of features were found to have reached favourable condition, reflecting the many challenges nature still faces in Scotland.

However a further 13.4% have been assessed as on the road to recovery. Over the year, the condition of 47 natural features improved to favourable or recovering condition, while 76 deteriorated to unfavourable condition.

There is little that can be done to reverse some of the sites in trouble, at least at a local level. That is because they are the result of global environmental change, such as declining seabird populations which are thought to be related to changes in prey distribution. Climate change is also believed to be a factor in the decline of a number of sites and poses a long-term threat to Scotland’s nature.

However, the SNH report, which coincides with Invasive Species Week, shows that “aliens” remain the single biggest reason for features being in unfavourable condition, representing 21% of all negative pressures, followed by overgrazing (17.6%).

Not all “invasive species” are necessarily foreign . Gorse, bracken and nettles, which occur naturally in Scotland, can be just as destructive as non-native plants and animals such as giant hogweed.

They can hurt important habitats and the flora and fauna they support by competing for nutrients and light.

SNH has been working with partners across Scotland to address these and other pressures and put important natural sites on the road to recovery.

Sally Thomas, SNH Director of People and Nature, said: “It’s encouraging to see that the majority of natural features in Scotland are either in good condition or on the road to recovery.

“However, these findings also clearly illustrate the challenges that nature faces and we know that more needs to be done.

“That’s why we are working closely with partners, farmers and landowners to help them to manage sites in a way that tackles invasive species and overgrazing on protected areas and ensures that our natural heritage is safeguarded for future generations.”

Examples of this work in action include Lower Wick River Site of Special Scientific Interest (SSSI) in Caithness where the control of toxic giant hogweed is making headway, preventing the plants from flowering and resulting in a significant decline in their numbers, and Ballantrae Shingle Beach SSSI in South Ayrshire, which is also improving following the treatment of invasive Japanese knotweed at the site.

At Dumbrock Loch Meadows SSSI a management agreement with the landowner of the largest lowland grassland in Stirlingshire has resulted in better managed grazing, bracken treatment and the removal of Japanese knotweed.

Meanwhile at Cleugh SSSI in Dumfries and Galloway the condition of the grassland is recovering following a similar management agreement, one of hundreds, to reduce grazing pressure and remove encroaching scrub and thistles - allowing flowering plants to thrive.

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

SNH’s recently announced Biodiversity Challenge Fund of up to £2 million is also targeting funding at projects that will help our most at-risk habitats and species, connect existing nature reserves and protected areas and tackle invasive species.

Not everyone is happy. Labour’s Claudia Beamish said the Scottish Government was “ continuing to fail our most vulnerable wild places”. with improvement “flatlining”.

She added: “Some of this can be attributed to invasive species but, as the First Minister herself admitted, the government is hitting only 7 of the 20 Aichi targets on biodiversity and it is patently obvious that the SNP Government’s actions are not enough.”