Hill fires could prove 'catastrophic' to habitats, says report

Fires in critical parts of the Belfast hills could prove "catastrophic" to the survival of precious upland heath habitat, a report has revealed.

However the study commissioned by the Belfast Hills Partnership, has sprung encouraging news for the area despite wildfires that threatened large swathes of the hills in summer 2008.

The outbreaks caused serious damage to wildlife habitats with fire fighters being tasked to over 40 incidences of malicious burning in the hills over the summer months.

The upland heath however can recover depending on how deep and prolonged the fires had been, the report found.

The study was carried out by Quercus, Northern Ireland's research centre for biodiversity and conservation biology at Queen's University. Scientists studied three major areas in the hills at Slievenacloy Nature Reserve, Divis and the Black Mountain and Cave Hill.

The team of scientists was contracted to survey and make recommendations for the areas of heather and bog across the summits.

The study also recommended the monitoring of peat and soil erosion particularly after burning episodes.

Further research at Queen's has already been stimulated by the study into topics such as the effects of grazing levels on upland heath and the impact of fires on seed banks.

A seed bank sample (pictured) is a range of plant seeds found in the soil. When vegetation is burnt off, it is the soil seed bank which is vital to new plants emerging.

Scientists discovered that older scrub areas characterized by "woody shrubs" such as in parts of Cave Hill, produced smaller seed banks.

This means that an outbreak in these areas could be "catastrophic" with insufficient seeds present in the soil to enable recovery from fire.

That would lead to serious erosion and loss of habitat.

"As heather enters into the degenerate phase, it tends to produce less seeds. Older stands of heath may have a lower density of viable seeds below them in the seed bank. So in the case of a major disturbance, such as an accidental fire, it may prove catastrophic as the post-fire regeneration will be hindered by a poor seed bank," the report said.

The study recommended that such areas be made available for grazing to encourage new growth and more seeds.

"It would be advisable to reintroduce some more targeted disturbance through grazing at these key sites (at Cave Hill), whilst maintaining the right of the public to visit this important landscape in the Belfast hills.

"The continued conservation of the Belfast hills' upland heath habitat seems assured through the careful management of its sites, by its governing bodies and the preservation of a healthy seed bank that will allow vegetation communities to continue to recover from disturbance episodes," the report said.

Dr Jim Bradley of the Belfast Hills Partnership said the precious habitat of upland heath has been under threat across Northern Ireland, but its status in the Belfast Hills had been difficult to judge until now.

"The study concentrated on the three big areas at Slievenacloy, Divis and the Black Mountain and Cave Hill that are open to the public and which still make up the majority of upland heath in our hills," he said.

"The study gave us a detailed snapshot of how the upland heath is doing, which gives us cause for both concern and encouragement."

He said the scientists compared the size and extent of upland heath on the three sites compared to aerial shots of the area they had from 1952.
 
"The good news is that the overall area of upland heath has actually increased from roughly 342 hectares to 365 today, but this is mainly due to an increase at Divis Mountain. The upland heath at Slievenacloy and Cave Hill has shrunk," said Dr Bradley.

Some 17 birds of conservation concern were found breeding in the heath including linnet, skylark, grasshopper warbler and reed bunting, with skylarks and meadow pipits the most widespread upland heath species.

In terms of agricultural use of the hills, the study found that the heath had not suffered from under or over grazing.

One interesting discovery was also that of an outbreak of heather beetle at Slievenacloy.

"Although this can lead to large patches of heather dying off, this small beetle is native and disappears and reappears in cycles causing only temporary damage, which the heather usually bounces back from. We were able to check out the other sites for other outbreaks and didn't find anything of concern.

"While it is clear that the sites are being well managed, Quercus outlined a number of management proposals such as managing for more varied heather heights and spread to encourage even more nesting birds.

"In the meantime, our upland heath is still in fairly good health and well worth preserving," said Dr Bradley.

Quercus was established as a partnership between the Northern Ireland Environment Agency (NIEA) and Queen's University, Belfast.

The report and supplementary study are in the downloads section.