Presentation on theme: "Axiophytes in the landscape (or – everything you wanted to know about axiophytes but were afraid to ask...) Sarah Whild 1, Alex Lockton 2, Jeremy Ison."— Presentation transcript:
Axiophytes in the landscape (or – everything you wanted to know about axiophytes but were afraid to ask...) Sarah Whild 1, Alex Lockton 2, Jeremy Ison 3 and Richard Aisbitt 3 Division of Biology and Conservation Ecology, Manchester Metropolitan University 1, Whild Associates/BSBI 2, School of Biosciences (University of Birmingham) 3
Axiophytes – what are they? This innovative approach has allowed for the creation of county indicator lists that can be used for conservation planning for sites and wider landscape use. Axiophytes (worthy plants or ecological indicators) have been used by the Botanical Society of the British Isles (BSBI) as a way of creating indicator species lists for vice-counties throughout Britain and Ireland
Axiophytes – what are they? An exception to the 25% rule can be made for species in conservation habitats that are particularly well represented and widespread in the county. An axiophyte list for a county is derived by taking all species that were restricted to BAP habitats (90% of records) and also found in 25% or fewer tetrads in the vice-county. These axiophytes can then be allocated to one or more broad habitat types.
Axiophytes have been used for: Assessing wildlife sites Site selection and monitoring Prioritising sites for habitat restoration Identifying landscape units for broad- leaved tree planting
Using axiophytes for site selection and monitoring in Devon and Wiltshire:
How effective are axiophytes as a measure of site condition? Are significantly more axiophytes recorded for high quality sites than those of low quality and can this be used to discriminate between two sets of sites? Do grid squares containing designated sites have significantly more axiophytes than those that do not? Are individual axiophytes more likely to occur in high quality sites than those of low quality Can coincidence maps of axiophytes allow for targeted surveying at a landscape scale?
County Wildlife Sites (CWS) in Devon were previously assessed using the Integrated Habitat System (IHS) which does not require any species identification. CW sites were assessed without any empirical evidence in the form of validated biological records.
Broad habitat types in Devon
Tetrad axiophyte coincidence map for Devon
A list of 416 axiophytes were identified for Devon There are 2078 County Wildlife Sites and data were analysed for 29 that were approved as CW Sites and 23 that had been rejected using the IHS scheme together with a panel of local experts. Figures suggested a threshold of 20 axiophytes would be needed to qualify as a CW Site and this was used to predict which sites would be accepted at the selection panel meeting. Two sites that would have been accepted by the axiophyte method were rejected and six sites that would have been rejected were accepted out of a total of 41 sites.
A list of 311 axiophytes were identified for Wiltshire Counts of axiophytes were compared across sites with different levels of protection SSSIs had an average of 46 axiophytes WWT reserves had 45 (very close to SSSIs) Unprotected CWTs had 24 From these figures it was relatively straight forward to suggest a proposed cut-off point for designation for SSSIs and also for CW Sites
A tetrad coincidence map of axiophytes for Wiltshire suggested that axiophyte coincidence mapping could be used to target new sites that had not been previously identified for conservation Hot spots showed tetrads that stood out as having no designated sites but high levels of axiophytes – thus providing targets for survey
Using axiophytes for conservation planning
Axiophytes of the Meres and Mosses 123 species were chosen including 18 bryophytes The county recorders for Shropshire, Cheshire and Staffordshire drew up a list of wetland axiophytes typical of the meres and mosses A coincidence map of these species was then produced in order to highlight hotspots for restoration and conservation The most important plant species for the Meres and Mosses are wetland species
Sites were then ranked according to total axiophyte species richness across time
RankTotalCurrentDeclineKey sites %The Mere, Ellesmere %Bomere Pool %Cole Mere %Wybunbury Moss %Whixall Moss %Bomere, Shomere & Betton Pools %Hatch Mere & Flaxmere %Brown Moss %Sweat Mere & Crose Mere %White Mere %Aqualate Mere %Wem Moss %Oak Mere %Rostherne Mere %Berrington Pool %Clarepool Moss & Newton Mere %Danes Moss %Hencott Pool %Fenemere %Balterley Heath
DC0 <1929 DC DC DC DC DC52010 plus Date class 1 DC1 ( ) is noticeably under- recorded in all the sites but the other date classes have comparable recording effort. Taking the four sites with the largest total decline in number of species, we can give a more detailed breakdown by date class, showing variations in recording effort.
The Mere, Ellesmere Hencott Pool Bomere PoolWhite Mere
But White Mere is noticeably different, with no change in the number of axiophytes between DC0 and DC2, and no change between DC3 and DC4. Three of the sites have broadly similar profiles, with the number of axiophytes decreasing by a factor of 2 between DC0 and DC2, and again halving in number by DC4. This suggests that White Mere retained its axiophytes until relatively recently, and it has not deteriorated noticeably in the recent past. This could be justification for prioritising resources on White Mere, as recent changes are more likely to be reversible. Taking the four sites with the largest total decline in number of species, we can give a more detailed breakdown by date class, showing variations in recording effort.
Sweat Mere – a site that has remained in favourable condition
What to do about White Mere? How do the axiophytes break down into habitats? AncientRecentPresenttotal Bog22 Carr1135 Grassland415 Marginal76922 Open water123 Woodland Total
Bog species have disappeared completely (Andromeda polifolia) Carr is in reasonable condition Grassland disappeared long ago with a mixture of species including calcicoles Clinopodium acinos and marshier species such as Triglochin palustris Marginal species have been hit hard with Schoenoplectus tabernaemontani, Oenanthe aquatica and Phragmites australis Dry woodland is in favourable condition
Most of these species are light loving species of open, wetter conditions so shade has increased. Remove trees from the waters edge in appropriate places and restore marginal grazing Target species Baldellia ranunculoides Bidens cernua Carex rostrata Cicuta virosa Elatine hexandra Littorella uniflora Luronium natans Oenanthe aquatica Oenanthe fistulosa Phragmites australis Ranunculus lingua Rumex hydrolapathum Schoenoplectus lacustris Schoenoplectus tabernaemontani Triglochin palustris
Conservation resources should be focused on the sites with the greatest number of these axiophytes, and the greatest urgency is for sites where there is a demonstrable decline This can only be detected retrospectively, so evidence of a recent loss of axiophytes is the appropriate trigger for intervention. White Mere is the site with the highest and most recent decline
Axiophyte data tables can be used for monitoring further changes in the conservation status of the meres and mosses. The more frequently that the sites are thoroughly surveyed, the more powerful this technique becomes. To maximise the potential of this sort of analysis, all SSSIs should be surveyed thoroughly at least once a decade.
Axiophytes and Opportunities – a case study in working with local partners with biological recording data In 2006 the Forestry Commission asked Shropshire County Council (now Shropshire Council) if they could provide a Woodland Opportunity map which highlighted areas that were more, or less, sensitive to new woodland planting. The use of axiophytes to produce such a map would provide an evidence-based approach to mapping.
Axiophytes and Opportunities – a case study in working with local partners with biological recording data Methods An axiophyte list for Shropshire was derived by taking all species that were restricted to BAP habitats (90% of records) and also found in 25% or fewer tetrads in the vice-county. These axiophytes were then allocated to one or more broad habitat types. The woodland and grassland axiophytes were then coincidence- mapped to identify the areas of greatest value for woodland and grassland. The coincidence data were transferred to GIS and mapped onto Landscape Description Units so axiophyte species densities could be allocated to each landscape patch.
Axiophytes and Opportunities – a case study in working with local partners with biological recording data
Results The resulting map then showed where woodland planting schemes could take place without compromising species- rich grassland and where woodland planting schemes could work effectively to link existing blocks of ancient woodland. Conclusions and applications This demonstrates how existing empirical, repeatable, presence- absence data is used to produce habitat maps which would otherwise have been expensive to collect and subject to a high degree of subjectivity. The resulting map is quantifiable and evidence-based. Woodland planting schemes in Shropshire can now be targeted more effectively. This system has been adopted by the West Midlands Biodiversity Group.
What can we learn from case studies on axiophyte use? Axiophytes can provide useful insights into how to assess sites empirically, using an evidence-based approach Axiophytes indicate favourable conditions – the more axiophytes the better quality the habitat Axiophytes can include bryophytes, not just vascular plants They can be used to answer specific questions on site conservation, conservation prioritization and landscape scale issues They should be used with a small degree of caution, bearing in mind issues of scope of recording especially when using time-sliced data
References Aisbitt, R Can axiophyte counts be used to assess wildife sites? University of Birmingham MSc Thesis Belton, L An algorithm to enumerate axiophyte richness in SSSIs. BSBI Recorder 15. Ison J Axiophyte diversity versus total species diversity in Devon. BSBI Recorder 15. Lockton, A., Wrench, D., Whild, S. Diack, I. & McCullagh, F Identifying conservation priorities in the Meres & Mosses Natural Area by using axiophytes. Unpublished report to Natural England.