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 youalison.hester@hutton.ac.uk

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