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Evaluation of habitats for nature conservation zTo a greater extent than ever before, habitats and species are threatened. zConservation will increasingly.

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Presentation on theme: "Evaluation of habitats for nature conservation zTo a greater extent than ever before, habitats and species are threatened. zConservation will increasingly."— Presentation transcript:

1 Evaluation of habitats for nature conservation zTo a greater extent than ever before, habitats and species are threatened. zConservation will increasingly be required and involve: z - designation of sites for various degrees of protection z- implementation of management plans zHow do you select a site for conservation? zNot all habitats can be conserved, and some habitats can be afforded greater priority for conservation than others. zThis lecture introduces a number of important criteria that are used in assessing the conservation value of a site.

2 Anglesey is a large (72,000 ha) island off the north coast of Wales zLakes and reedbeds ysupport the greatest number of breeding wildfowl in Wales ylime-rich fens are unique in Wales ywildlife and plant communities rare or absent elsewhere in Wales yWet pastures scattered across the farmland still provide food and breeding sites for wading birds.

3 Cors Erddreiniog 289-hectare SSSI, includes a 190-hectare National Nature Reserve and is the largest fen in Wales. Black bog rush Schoenus nigricans Blunt flowered rush, Juncus subnodulosus Great fen sedge Cladium mariscus Fly orchid Ophrys insectifera Marsh gentian Gentiana pneumonanthe, Southern damselfly Coenagrion mercuriale at its most northerly location

4 Llyn Rhos-ddu This shallow lake is dammed by the Newborough Warren sand dune system and is part of that National Nature Reserve. The lake supports a good range of aquatic plants and animals including mare's-tail Hippuris vulgaris. Water level was accidentally lowered about 0.6 metres some years ago. The AWS group has helped to install a sluice, being used to restore the water level.

5 Purple saxifrage Saxifraga oppositifolia Snowdon lily Lloydia serotina Rainbow beetle Chough Snowdonia

6 What features make a site of conservation value? zSize zDiversity zNaturalness zRarity zFragility zTypicalness zRecorded history zPosition in ecological unit zPotential for improvement/restoration

7 A word of caution…………... zThese criteria are not definitive: zthey are not strictly independent, or all necessary for consideration all of the time zthey are not entirely objective zthere are frequent exceptions HOWEVER they are intended to stimulate a comprehensive evaluation they provide a structured evaluation process they are widely and, with experience, reliably used

8 What features make a site of conservation value? zSize zDiversity zNaturalness zRarity zFragility zTypicalness zRecorded history zPosition in ecological unit zPotential for improvement/restoration

9 Size zlandscape suffers from severe fragmentation of natural habitat zA general ecological rule is that larger habitats contain proportionally more species than smaller habitats zspecies population sizes tend to be larger in larger habitats zBut size isnt everything! zSmall areas may be of high quality/very rare habitat za small habitat may have a high proportion of the local, national, or international population of a species

10 What features make a site of conservation value? zSize zDiversity zNaturalness zRarity zFragility zTypicalness zRecorded history zPosition in ecological unit zPotential for improvement/restoration

11 Diversity zPhysical, habitat, species and community diversity zUsually, higher diversity is better ye.g. calcareous grasslands >50 species m -2 yimproved grassland ~2 species m -2 zHowever, diversity can be high, but of poor conservation value zDiversity is related to a number of different processes, and need to identify such processes that are important at a site

12 What features make a site of conservation value? zSize zDiversity zNaturalness zRarity zFragility zTypicalness zRecorded history zPosition in ecological unit zPotential for improvement/restoration

13 Naturalness zMore natural implies: yof greater conservation value yabsence of human interference (relative!) ya natural habitat can change over time (succession, env. conditions) zNeed to consider: zpresence of introduced species zhow the habitat differs from other less disturbed habitats zcan the habitat be maintained/improved zis another species dependent on it yGreenland whitefront goose favours grazing on improved grassland, the latter being of low intrinsic conservation value

14 What features make a site of conservation value? zSize zDiversity zNaturalness zRarity zFragility zTypicalness zRecorded history zPosition in ecological unit zPotential for improvement/restoration

15 Rarity zEstablish the wider distribution of a rare species/habitat ylocal, regional, national, international? zWhy is it rare? yLimit of geographical distribution yrelict populations (e.g. Arctic alpine flora) yspecialised local requirements zIs it likely to continue to survive? (long-term viability)

16 What features make a site of conservation value? zSize zDiversity zNaturalness zRarity zFragility zTypicalness zRecorded history zPosition in ecological unit zPotential for improvement/restoration

17 Fragility zthe degree of sensitivity of habitats, communities, and species to environmental change, and so involves a combination of intrinsic and extrinsic features (Ratcliffe 1977) zSuccession: natural dynamics of vegetation turnover zAnthropogenic disturbances yhow serious is the disturbance? (extent of damage) yhow likely is recovery? zUnderlying causes of fragility? zViability? zWithin what timescale?

18 What features make a site of conservation value? zSize zDiversity zNaturalness zRarity zFragility zTypicalness zRecorded history zPosition in ecological unit zPotential for improvement/restoration

19 Typicalness zSites can be selected and valued because tjhey represent the best example of a particular habitat (which may not be threatened). zWhat is the typical landform/habitat/community for an area? zwhat are the typical species for a habitat/community?

20 What features make a site of conservation value? zSize zDiversity zNaturalness zRarity zFragility zTypicalness zRecorded history zPosition in ecological unit zPotential for improvement/restoration

21 Recorded history Position in ecological unit zHabitat value may be enhanced if their history and management is known, for the management of one site, and understanding of others. zAvailability and quality of scientific and land use records zavailability of accessible natural evidence ypollen record in peat bogs zrelevance of records to value of the features zPosition in ecological unit zmost obvious example is offshore island zreflects isolation, fragmentation, size of unit, buffer area, quality of buffer area, land use around habitat

22 What features make a site of conservation value? zSize zDiversity zNaturalness zRarity zFragility zTypicalness zRecorded history zPosition in ecological unit zPotential for improvement/restoration

23 Potential for improvement/restoration zReflects isolation, fragmentation, size of unit, buffer area, quality of buffer area, land use around habitat zHabitats are usually imperfect zNeed to assess the potential for improvement zcan there be total recovery? zWill partial recovery be adequate? ye.g. removal of weeds, Rhododendron yremoval of exotic predators

24 What features make a site of conservation value? zSize zDiversity zNaturalness zRarity zFragility zTypicalness zRecorded history zPosition in ecological unit zPotential for improvement/restoration

25 Summary z639.9-SPE. Evaluation and assessment for conservation ecological guidelines for determining priorities for nature conservation. Spellerberg Ian F. zGoldsmith. Monitoring for conservation and ecology.


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