If the restoration site is large enough a natural herbivore population might be introduced to slow down succession to a more natural pace, but in smaller areas a decision has to made to allow succession to continue with no management and lose all the early succession al stages or to artificially maintain the habitat to give more diverse succession al stages. (Sutherland, get proper ref from lib)
I believe that connectivity is one of the most important factors of any restoration project. Natural succession can proceed, as succession proceeds the initial target species will move on to a more favourable location and new species will colonise your area, but this is only possible if areas are interconnected. An important way to do this is to help restore traditional agriculture, replant hedgerows and protect the areas we already have.
How can the goals set out in the plan be achieved?
Reasons for degradation
Each site of restoration is inevitably going to be different than any done before it but there is a lot of underlying similarities, stop whatever is degrading the target habitat, remove any exotic species, repopulate with native species. There are different schools of thought on how each of these steps are approached.
Degraded ecosystems may be a result of; Overgrazing, agriculture,water pollution, hunting, harvesting of prey, development (towns, roads, harbours), habitat loss and fragmentation, and climate change. On a local scale we do not have much control over climate change, but as trends predict a global warming, it might be taken into consideration to restore cold tolerant ecosystems closer to the poles, and let succession determine the fate of more equatorial sites (get example)
Soil as a major factor in a programme of restoration
When an area is degraded either the vegetation of both vegetation and soil are affected and in turn all the animals. If vegetation has been affected and the soil left relatively untouched for example due to fire, overgrazing or storms secondary succession will occur when the damaging factor has been removed.
For an area where the soil has been affected, for example seeds, propagules removed and even increases of nutrients secondary succession will take a long time to occur. Recolonisation from outside will most likely occur. This happens with agriculture, the soil has been used for many generations and all evidence of past habitat has been all but erased. But this also happens in nature through retreating glaciers, volcanic ashes, river alluvium, and landslips. Primary succession occurs on sites like these but may take up to 100 years as is shown by the glacial moraines in Alaska.
If soil is striped it can be restored by taking soil from other areas, but this is expensive and only viable if there another site with available soil on it. And the new soil wont have the same characteristics of the original soil. To assist the habitat species can be brought in from surrounding areas to accelerate these natural processes. Once vegetation gets a grip it will curb erosion, strengthen the soil structure and add nutrients to it. Nurse species can be used for this, growing fast, dying then creating a matrix of protective material. If any topsoil is available it can e used no matter how little , the retention of soil moisture is very advantageous.
(Bradshaw 1997)
The problem of exotic species
Exotic species have encroached on many habitats and communities throughout the world having a negative impact on them, reducing native biodiversity, altering hydrologic and fire regimes. Controlling exotic species can be labour intensive and costly. Extensive research into the landscape ecology could be invaluable. Borgman et al (2005) suggest the land use of the surrounding areas influences invasion by exotic species (and undesirable native species). As it is more likely to get exotic invasive species from disturbed landscapes (Hobbs 1989) it could be more profitable to site programmes of restoration further afield and closer to a similar older habitat thus increasing the potential for native plant recolonisation and survival ( Marvier et al 2004) As well as strategically placing restoration sites buffer zones can be included curbing development and this can help prevent invasion of exotic species (Pysek et al 2002)
The advantages of using grazers
Grazing is a natural part of our landscape and any restoration project should try and include as a natural grazing stock as possible. In 2006 two water buffalo were introduced onto the kingfishers bridge site in eastern England (Gulickx et all 2007). Water buffalo maintain a low vegetation structure and help maintain a more heterogeneous habitat. An RSPB site at Arne county Dorset southern England use cows to graze the reeds at their site with a few sikka deer. Different animals are known for different grazing qualities, heath, grass, wetlands, highlands, and for controlling succession (Brook et al 2007). If the restoration site cant accommodate grazers intensive management is most likely, using human resources to control undesirable species and even extreme measures of herbicides being used on conservation sites which can and has led to public complaints. Grazing is recognised as a sustainable, environmentally friendly, and cost effective way to control succession(Brook et al 2007)
Grazing and burning are commonly used for the restoration and management of heathland but burning produces a lot of potash thus increasing the fertility of the soil and encouraging the growth of undesirable bracken (Brook et all 2007)
The advantages and disadvantages of using a keystone species
In some sites it is a good incentive to have a 'keystone' species. Trying to help numbers of a certain creature ensures the restoration and good management of a site. Although high specificity might not always be the best way to approach a restoration programme. It can led to intensive management and complete disregard for common native species like deforestation for wetland land creation, using herbicides, filling up rivers with stocked fish and them having no affect on the native population. All these factors can end up damaging the landscape and result in public complaints and withdrawal of support.
Ecological restoration should aim to restore the broad ecology, fiving a high diversity but if there is a target species it too must be embedded within the matrix.(parker 1997)
Restoration of traditional farming methods
The restoration of older farming methods has to be the main goal in country's that intensively farm due to degradation from rotovating, fertilising and reseeding. In Europe numbers of farm birds have been on the decline partly due to a decrease in food availability. Leaving stubble in fields over winter leaves more seed on the ground for birds and this is associated with higher survival rates of number of birds. A study in 1997-1998 in central England showed that stubble in fields produced higher numbers of grey partridge, chaffinch, yellowhammer and reed bunting (Moorcroft et all 2002) . Restoration and management of hedgerows is pivotal for the conservation of many plants and animals in intensively farmed areas (Boutin et al 2002)
Holzschuh (2007) shows that organic farming can help restore flowering plants in three test sites in central Germany, by increasing the amount of bees. This helps to prove the need and success of agri-environment schemes in restoring biodiversity in our countryside.
Monitoring and communication
Conclusion
Restoration is continually being improved upon and by publishing results of tests we can learn from others, getting rid of older practices and using newer more scientific practices based on controlled experiments or by years of successful experience. The practice of bramble bashing has been discontinued in some areas and grazing and herbicide used instead, drystone walls have been used to increase nest sites for butterflies who previously used coppiced ditch habitats (Slater 2007)
Literature cited
Borgmann Kathi L. and Amanda D. Rodewald. 2005. Forest Restoration in Urbanizing Landscapes:Interactions Between Land Uses and Exotic Shrubs.Restoration Ecology Vol. 13, No. 2, pp. 334–340
Boutin C., Jobin B., Bélanger L. & Choinière L. 2002. Plant diversity in three types of hedgerows adjacent to cropfields. Biodiversity and Conservation, 11, 1-25
Bradshaw Anthony D. 1997. The importance of soil ecology in restoration science. Pages 33-64 in Urbanska, Krystyna M., Webb, Nigel R, and Edwards, Peter J, editors. Restoration Ecology and Sustainable Development. Cambridge University Press.
Brook S., McCracken M., Bulman C.R., Camp P. and Bourn N.A.D. 2007. Post-burn bracken Pteridium aquilinum control to manage habitat for the heath fritillary butterfly Mellicta athalia on Exmoor,
Somerset, England. Conservation Evidence (2007) 4, 81-87
Gulickx M.M.C., Beecroft R.C. and Green A.C.2007.Introduction of water buffalo Bubalus bubalis to recently created wetlands at Kingfishers Bridge, Cambridgeshire,England. Conservation Evidence (2007) 4, 43-44
Hobbs, R. J. 1989. The nature and effects of disturbance relative to invasions.Pages 389–405 in J. A. Drake, H. A. Mooney, F. di Castri, R. H. Groves, F. J. Kruger, M. Rejmanek, and M. Williamson,
editors. Biological invasions: a global perspective. Scope 37. John Wiley and Sons, Chichester, United Kingdom.
Holzschuh A., Steffan-dewenter I., Kleijn D. & Tscharntke T. 2007. Diversity of flower-visiting bees in cereal fields: effects of farming system, landscape composition and regional context. Journal of Applied Ecology 44, 41–49
Marvier, M., P. Kareiva, and M. G. Neubert. 2004. Habitat destruction, fragmentation, and disturbance promote invasion by habitat generalists in a multispecies metapopulation. Risk Analysis 24:869–878.
Moorcroft D., Whittingham M.J., Bradbury R.B. & Wilson J.D. 2002. The selection of stubble fields by wintering granivorous birds reflects vegetation cover and food abundance. Journal of Applied Ecology, 39, 535-547 birch
Pysek, P., V. Jarosik, and T. Kucera. 2002. Patterns of invasion in temperate nature reserves. Biological Conservation 104:13–24.
Richardson, D. M., N. Allsopp, C. M. D’Antonio, S. J. Milton, and M. Rejmanek. 2000. Plant invasions - the role of mutualisms. Biological Review 75:65–93.
Slater M. 2007. Creation of a drystone wall to create egglaying habitat for grizzled skipper Pyrgus malvae at Ryton Wood Meadows Butterfly Conservation Reserve, Warwickshire,
England. Conservation Evidence 4, 35–40
Weiher Evan . 2007.On the Status of Restoration Science: Obstacles and Opportunities. Restoration Ecology Vol. 15, No. 2, pp. 340–343.
Wilkins, S., D. A. Keith, and P. Adam. 2003. Measuring Success: Evaluating the Restoration of
a Grassy Eucalypt Woodland on the Cumberland Plain, Sydney, Australia. Restoration Ecology Vol. 11 No. 4, pp. 489–503.
Parker Thomas V. and Pickett Steward T.A.. 1997. Restoration as an ecosystem process: implications of the modern ecological pardigm. Pages17-32 in Urbanska, Krystyna M., Webb, Nigel R, and Edwards, Peter J, editors. Restoration Ecology and Sustainable Development. Cambridge University Press.
Sutherland. The conservation Handbook Reserve Management and Policy
Urbanska, Krystyna M., Webb, Nigel R, and Edwards, Peter J, editors. Restoration Ecology and Sustainable Development. Cambridge University Press.
