Date post: | 30-Jun-2015 |
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Environment |
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How can research contribute to future resilient landscapes? Case studies from woodland habitats
Alison Hester, Ruth Mitchell, Alice Broome
Talk structure
• Primary research – what, where, when, why, how…?
• Synthesis – bringing together different research findings to draw common conclusions and identify gaps
• Advice/recommendations – what can we recommend and with what degree of confidence?
1. Primary research – contribution to future resilient landscapes
• Direct impacts of pathogen on ‘host’ tree(s); presence of resistant genotypes; cures (e.g. garlic & sudden oak death)
• Wider impacts – dependent species; other ecosystem functions (e.g. nutrient cycling); ‘alternative’ tree species?
• Factors affecting infection and spread – global transport of seedlings (etc); spatial distribution/condition of trees; habitat configuration within the wider landscape…
* Red colour = examples I will show today
1a. Primary research – dependent species / ecosystem function
e.g. the species databases we examined (for tree species use) have >1.2 million UK field records for lichens (BLS) and >1 million for fungi (FRDBI)
e.g. for ecosystem functions of ash, we found 420 published field/lab studies on this topic
Both require intensive, field and lab based measurements…
1b. Primary research – habitat configuration within the landscape
• Requires spatial data collection – air photos/satellite, field survey then spatial modelling
• e.g. how connected are our forests at present? (Gimona et al, JHI)
• Implications for species spread (good and bad)
Gimona et al (2012)
Landscape permeability to forest species
Present-day connectivity potential 2050s projection – Climate & Land Use Change
90th percentile
75th percentile
Current Broadleaved Woodland
90th
percentile75th
percentilePotential Loss of connectivity
Potential loss due to agric. intensification
2. Synthesis – contribution to future resilient landscapes
• Data collation – hugely important for providing best available information and levels of confidence – examples:
Collation of individual studies into a searchable database – e.g. JHI ash database – example outputs: species most at risk if host tree declines; ‘alternative’ host tree species
Meta-analysis of published studies – e.g. tree resilience to different pathogens; ecosystem functions of different tree species...
• Future projections – speed of spread; likelihood of resistance developing; impacts of climate change …
2a. Synthesis: AshEcol Database (MS Access)
Can create such a database for any tree species …– critically important to assess potential impacts of other pathogens on UK native tree species, e.g.:• Oaks: oak processionary moth (Thaumetopoea processionea ),
Phytopthora (Phytophthora quercina)• Oak, beech: Phytopthora (P. ramorum & P Kernoviae)• Elm: Dutch elm disease (Ophiostoma novo-ulmi)• Scots pine: needle blight (Dothistroma septosporum), pine pitch canker
(Fusarium circinatum), pine processionary moth (Thaumetopoea pityocampa), pine wood nematode (Bursaphelenchus xylophilus )
• Ash: emerald ash borer (Agrilus planipennis).
-> AshEcol: numbers of ash-associated species
* Plus 78 vascular plants & other birds/mammals that use habitat not tree
Group
High Partial Cosmopolitan UsesBird 7 5Bryophyte 6 30 10 12Fungi 30 38Invertebrate 53 36 19 131Lichen 17 231 294 6Mammal 1 2 25
Total 106 343 330 174
Level of association with F. excelsior
-> AshEcol - species most at risk from loss of ashSpecies group
Red Amber Yellow GreenBird 0 3 4 5Bryophyte 6 3 39 10Fungi 30 1 37 0Invertebrate 53 73 94 19Lichens 17 45 190 294Mammals 0 7 19 2
Impact of Ash dieback
Takes conservation status into account Can also be assessed by location/ species distribution/ presence of
alternative ‘host’ tree species
Alternative species if ash is lost?
Decompos-ition
Litter quality
Nutrient cycling
No. of a-a species
Acer campestre Acer pseudoplatanus Alnus glutinosa Betula pubescens/pendula Fagus sylvatica Juglans regia Populus tremula Prunus avium Quercus robur/petraea Sorbus aucuparia Tilia cordata
2b. Synthesis - alternative tree species, both as ‘hosts’ and to ‘replace’ ecosystem function?
Most suitable alternativeIntermediate alternativeLeast suitable alternative
Potential conflict
?
Ecosystem fu
nction v specie
s supporte
d
NB these conclusions are dependent on available data – in some cases there are few or no data and this must be explicit, to indicate confidence level…
2c. Synthesis – impacts of climate change – tree health
• Site conditions (now and into the future) are critical for tree health – trees under stress are more vulnerable to pests and pathogens
• Data synthesis examples (Broadmeadow & Ray 2005 - FR):
-> wider landscape issues and climate change – habitat networks for species movement?
Gimona et al (2012)
Landscape permeability to forest species
Present-day connectivity potential 2050s projection – Climate & Land Use Change
90th percentile
75th percentile
Current Broadleaved Woodland
90th
percentile75th
percentilePotential Loss of connectivity
Potential loss due to agric. intensificationLandscape permeability to forest species
Present-day connectivity potential 2050s projection – Climate & Land Use Change
90th percentile
75th percentile
Current Broadleaved Woodland
90th
percentile75th
percentilePotential Loss of connectivity
Potential loss due to agric. intensification
Source: Gimona et al - JHI
3. Advice & recommendations - future resilient landscapes
• Simplified searchable databases for woodland managers – best available information for each pathogen/tree species
• Woodland management guidance for areas vulnerable to loss of trees due to pathogen attack e.g.:
Which tree species are best alternative hosts?
Are tree species mixtures better than single species?
Protocols for assessing different management methods to reduce damage/aid recovery at different sites
• Wider landscape context - spatial modelling and analysis
• Some tree alternatives only ‘good hosts’ for certain groups of ash-associated species
• Conifers generally not “good” for ash-associated species • Oak ‘good host’ for many ash-associated species
3a. Alternative tree species as hosts? – examples for ash-associated species
3b. Advice - are mixtures of species better than single species?
Quercus robur/petraea = 68.5%
19 tree species = 91.6%Corylus avellana = 86%Fraxinus ornus = 83.6%Ulmus procera/glabra = 78.6%
• YES – mixtures will support the greatest number of species
• YES – other research (Ray et al – FR) has also shown reduced pathogen attack in mixed forests
• BUT: site conditions need to be suitable for species selected
• AND ecosystem function also needs to be considered…
3b. Five step process to assess different site management options
1. Assess biodiversity of site (desk study – site records, NBN database…)
2. Short list priority species for conservation (AshEcol database)
3. Identify alternative tree and shrub species that could support the ash-associated species if ash is lost (AshEcol)
4. Assess site conditions on the ground – trees present, etc
5. Assess management options
15 case study sites
Num
ber o
f site
s
0
1
2
3
4
5
6
7
<10 10 - 49 50 - 99 100 - 149
Number of vulnerable species
Half the case study sites had 50+ species vulnerable to loss of ash
a. Species vulnerable to loss of ash:
-> Case study summary: vulnerable species; alternative trees and shrubs
Most case study sites had alternative ‘host’ trees and shrubs present, but often at low abundance
b. Status of alternative trees and shrub species:
-> Case study summary: management options to aid persistence of ash-associated biodiversity if ash is lost
Site IDCurrent management New management
Encourage natural regeneration
Introduce species by planting
1 min intervention no change X
2 min intervention no change X
5 min intervention no change X
13 min intervention no change X
8 coppicing no change X
7 coppicing no change X
14 thinning no change X
12 limited coppicing thinning/small patch felling X
15 min intervention thinning / group felling X
4 limited coppicing small patch felling X
6 min intervention thinning / group felling X
11 limited coppicing increase extent of coppicing X
9 min intervention group felling X
3 min intervention group felling X
10 min intervention group felling X
Incr
easi
ng c
hang
e in
site
m
anag
emen
t
phot
o R
Har
mer
photo M Mackinnon
Summary
• Research synthesis to provide ‘best available information’, level of confidence and gaps should underpin management decisions on tree health and future resilient landscapes
• We have powerful analysis tools and can readily do this for different pathogens and different tree species….NOW
• Pathogens can have rapid and devastating impacts on our species and landscapes – if we wait until there is an ‘impact’, it is often ‘too late’ to have much effect….
Pathogens are not always
predictable!
Thank [email protected]
Ash project team:• The James Hutton Institute• Forest Research• Royal Botanic Garden Edinburgh• University of Aberdeen• RSPB• Independent Bryologist
Funders:• Defra• DoE Northern Ireland• Forestry Commission• JNCC• Natural England• Natural Resources Wales• Scottish Natural Heritage