From University of Newcastle upon Tyne
Battle to save last stronghold of the red squirrel A UNIQUE conservation plan is stopping England's biggest surviving population of red squirrels from dying out in 11 years time due to a lack of food.
Kielder Forest District, whose 150 million trees span 200 square miles from County Durham to the Scottish border, contains England's biggest forest, and is one of the few places in England where red squirrels are still abundant. Numbers of the species are declining on a national scale and in 1995 the Government listed it as a priority species for conservation.
Researchers from Newcastle University, working with Forest Enterprise who manage Kielder, have helped foresters to redesign the layout of a conservation area which will ensure its native squirrels have adequate food and will survive for the next 40 years at least. The plan has the backing of neighbouring private landowners.
The Newcastle team hope to receive support to expand their work to the rest of Kielder District as the survival of the species as a whole depends on careful management of the forest habitat. The work has the potential to be applied to conservation areas for squirrels and other endangered species.
Wildlife experts estimate up to 10,000 native red squirrels live in Kielder Forest, which is also one of Europe's largest man-made commercial forests. The red squirrels at Kielder are an added attraction for the half a million visitors who visit the area each year and keep up to a third of local people in jobs in the tourism industry.
Kielder has a red squirrel action plan and one area, Spadeadam Forest, has already been designated as a squirrel conservation area.
University ecologists, from the Centre for Life Sciences Modelling (CLSM), assessed the layout for another proposed red squirrel conservation area at Kidland Forest, where several hundred of the animals are said to live. They found that a felling and design plan which Forest Enterprise was replacing would have drastically reduced food supplies for the squirrels.
The Centre, which has an international reputation for their expertise in the application of computer models for introduced or endangered species management, developed a computer population model for the squirrels.
This work is the culmination of 10 years of field and modelling work on red and grey squirrels and is made possible by the recent introduction of Geographic Information Systems (GIS) in forest management. The model is able to simulate the impact of proposed felling and restocking plans on red squirrel viability.
Kidland Forest, which is 2050 hectares and within Northumberland's Cheviot Hills, is considered to be an ideal conservation area for the threatened red squirrel due to its isolation and inaccessibility for grey squirrels currently colonising Northumberland.
The joint project assessed the suitability of Kidland for red squirrels over the next 40 years and showed that the felling proposed in the previous design plan for Kidland Forest would have removed large amounts of the main source of food for the squirrels - the seeds found in conifer cones.
Harvesting and replanting of timber is part of the normal cycle in a forest. The harvesting of timber is carried out on rotation and the ‘life –expectancy’ of a plantation depends on the type of tree, the soil and the 'wind-throw hazard' - older trees are at risk of being blown down by strong winds which rip their shallow roots out of the peaty forest soil.
Suggested plans to replace the felled trees with oak in parts of Kidland forest would also have affected the survival of the red squirrel. Broadleaf trees like oak are a source of food for the grey squirrel, which can out compete and replace the native reds.
The new forest design involves an increase in the retention of mature trees, the planting of a greater variety of conifers, and plans to plant oak trees have been switched to another area of the forest to ensure grey squirrels can not replace the reds at Kidland should they get there.
Dr Lurz said:
"The availability of a suitable habitat is a key resource determining the presence of a species in a particular landscape.
"When red squirrel population dynamics were simulated based on the current forest composition, the felling plan and possible tree seed compositions, the results indicated that red squirrels in Kidland may be reduced to a 'handful' of individuals (less than 20) and could face local extinction around 2012. This would be caused by the reduction in suitable habitat of cone bearing age over the next 20 years due to timber harvesting.
"If oak trees were planted and allowed to mature, the grey squirrel population was predicted to expand and to reach an average of 80 individuals by 2050.
But he added:
"The simulation results of the revised felling and restock plans indicate that red squirrels should persist for the next 40 years until the next rotation"
The development of computer models for native mammals such as the red squirrel and the availability of high quality forest maps or satellite images provides a unique opportunity for the conservation of endangered native mammals.
Graham Gill, forest manager of Kielder District said:
"The Newcastle University work has given us a much improved understanding of the habitat requirements of red squirrels which we are able to put to immediate effect in our redesign of Kidland Forest.
"Large conifer forests like Kielder and Kidland are rapidly becoming the last refuge of red squirrels in England and the decisions we take today have direct influence on the squirrel populations of 40 years in the future.
"Our new forest design plan does not offer any guarantees, but should help tip the balance a little more in this cherished animal's favour."
Notes to journalists:
1. The American grey squirrel was first introduced to Britain at Henbury Park, Cheshire, in 1876, and they were subsequently introduced elsewhere. As the grey squirrel has spread there has been a parallel decline in the numbers of the native red squirrel.
2. The red squirrel was listed as a priority species for conservation by the UK Government in the Biodiversity Action Plan, 1995.
3 Kielder Forest has been co-operating for many years on research projects into the conservation of red squirrels. Based on this research the current policy is to concentrate its conservation effort by maintaining within the coniferous woodland blocks of habitat which is less favourable for grey squirrel colonisation, and where appropriate co-operate with grey squirrel control programmes. The use of population models for forest planning purposes has recently become practical due to the introduction of computerised geographical information systems (GIS) which hold forest design and felling plans in digitised format.
5. Kielder Forest District is managed by Forest Enterprise which is the management agency of the Forestry Commission. Further facts and figures on Kielder Forest from: http://www.kielder.org/facts.htm