Native species conservation

 

Background

The Woodland Trust’s “Deed” does not refer to native species but Keeping Woodland Alive: The Woodland Trust’s plan for action 1 is targeted explicitly at the conservation of native woodland. 

Conventionally, species native to the UK are regarded as those that have arrived here since the last ice age without human assistance. Non-native species, therefore, are defined as those that have been introduced by humans, deliberately or accidentally. These definitions are based on a largely static view of the world. In reality, as climate has varied over the millennia, species have moved to different latitudes and altitudes that match conditions to which they are adapted (or have remained in situ and evolved to cope with the changing climate). 2

The degree of current anthropogenic change that is having an impact on species and habitats, poses further challenges to the maintenance of biodiversity and the conservation of native species. Loss of semi-natural habitats, intensive land use, the rate of climate change 3 and the introduction and spread of invasive non-native species are leading to severe depletion of biodiversity.

The paradigm of protected areas and fixed reserves is no longer adequate as a model for the conservation of native species. A more dynamic set of processes must be recognised within which conservation needs to operate. These principles are discussed in our publications, Expanding our Horizons 4 and Space for Nature,5 which outline the need to develop ecologically functional landscapes that allow for adaptive change and movement of species.

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The Woodland Trust's view

In this context the Trust’s approach to the conservation of what are regarded as native species is precautionary in nature, given the degree of uncertainty that is inherent in predicting future change. The Trust believes that:

  • Action should be focused primarily on habitat conservation, as knowledge of species and the way that they interact with other species will always be limited.6 Some species can be used as indicators of habitat continuity (e.g., ancient woodland plants) 7 and their presence can assist in identifying ancient woodland and other ancient habitats, which can then inform priorities for habitat conservation.4 5
  • Chance dispersal may be the only means by which many less mobile species, such as those found in ancient woodland, will be able to survive rapid climate change 8. Conservation should seek to:
  • increase the frequency with which species are able to move (e.g., by seeking a general reduction in the intensity of land use), and
  • enhance the degree to which individual sites and whole landscapes welcome the establishment of species when they happen to arrive from a long distance (e.g., by using habitat creation to buffer and extend semi-natural habitats, thereby reducing deleterious edge effects, particularly in areas of the country with a high density of ancient woodland that have greatest potential to be placed on a sustainable footing).4 5
  • Habitat creation should be achieved through natural colonisation, wherever practical. However, this will often not be possible and we believe that re-introductions and re-stocking are vital to conservation action providing that the species concerned are:
  • catered for by habitat management rather than by long-term species-specific actions, and are either
  • fundamental to sustaining a habitat (i.e., keystone species, e.g., trees), or 
  • can be used in a pragmatic way to promote wider issues of habitat protection, management, restoration and creation (i.e., flagship species, e.g., dormouse, which needs woods exceeding 50 ha to sustain healthy populations). 9

World Conservation Union (IUCN) guidelines 10 should be adhered to, including use of stock of the closest provenance available. For example, where it is necessary to plant trees within ancient woods, or native woodland is being created on adjacent land, this should be with site-native species of local provenance.
  • Specific actions to conserve individual species are justified where:
  • there is a legal obligation to do so (e.g., the Countryside & Rights of Way Act 2000), or they are
  • keystone species, or
  • flagship species.
  • When considering the need to control a species, its native or non-native status is unimportant. The key issue is whether it is causing significant ongoing habitat change or loss of other species, additional to that from climate change. However, even where this is the case, remedial action should only be undertaken if it could be sustained. For example: 
  • it will rarely be appropriate to eradicate beech planted outside of its historic range as climate space for this species is expanding rapidly north and west 2
  • sycamore control may only be justified and practical where it is not already established as a significant component of woods or in the surrounding landscape. 
  • Species should be retained that have cultural value (e.g., ancient non-native trees), including as reminders of past management (e.g., specimen conifers in planted ancient woodland sites), where they do not threaten to de-stabilise semi-natural habitats. While the Trust creates predominantly new native woodland, non-native trees may be planted for cultural reasons but normally only as a minor component.
  • New commercial crops, garden plants and species used for biological control should not be introduced to the UK unless it is known that they do not de-stabilise similar semi-natural habitats elsewhere, given that climate change may enable such species to become invasive in due course.
  • Concerted action should be taken to prevent the arrival and establishment of species that are likely to threaten our woodland biodiversity e.g. Asian longhorn beetle.

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References:

  1. The Woodland Trust (2001) Keeping woodland alive: The Woodland Trust’s plan for action (www.woodland-trust.org.uk/publications.htm)
  2. Harrison, P.A., Berry, P.M. and Dawson, T.P. (eds.) (2001) Climate change and nature conservation in Britain and Ireland: Modelling natural resource responses to climate change (the MONARCH project). UKCIP Technical Report
  3. Hulme, M., Jenkins, G.J. et al (2002) Climate change scenarios for the United Kingdom: The UKCIP02 Scientific Report. Tyndall Centre for Climate Change Research, UEA
  4. The Woodland Trust (2000) Woodland biodiversity: Expanding our horizons (www.woodland-trust.org.uk/publications.htm)
  5. The Woodland Trust (2002) Space for nature: Landscape-scale action for woodland biodiversity (www.woodland-trust.org.uk/publications.htm)
  6. The Woodland Trust (2000) Seeing the woods for the trees
    (www.woodland-trust.org.uk/publications.htm)
  7. Peterken, G.F. (2000) Identifying ancient woodland using vascular plant indicators. British Wildlife
  8. Wilkinson, D.M. (1999) ‘Plants on the move’. New Scientist (Inside Science 119)
  9. The Woodland Trust (2001) Position Statement - Species translocation
  10. Species Survival Commission (1995) IUCN/SCC Guidelines for re-introductions

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