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Arjen van Hinsberg, Janet Mol 8-4-2014

Dynamic modelling of impacts in Natura

2000 habitats

the Dutch response to the call for data

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Content

Ambitions & MethodsResults & ProblemsConclusions

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Ambition

Create a small set of regional representative sites which could be used to model effects of deposition on biodiversity

Create a policy relevant biodiversity endpoint

Use VSD+/Props

Arjen van Hinsberg 08-04-2013

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Selection of Sites 1(2) Policy relevant: Natura 2000

– 50% of the Dutch Nature Area’s– 51 Habitats out of 251

Sensitive to atmospheric deposition– Critical loads ranging from 5 kg/ha/yr – 35 kg/ha/yr– 45 Habitats– No marine or aquatic habitats

Regional representative: Focus on larger Habitats

Arjen van Hinsberg 08-04-2013

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Selection of sites 2(2)

Arjen van Hinsberg 08-04-2013

Size No Habitat types

Total Sensitive Selected

Very small (<100 ha) 8 8

Small (100-400 ha) 8 6

Average (400-1600 ha) 14 14 2

Large (1600-6400 ha) 10 10 5

Very large (>6400 ha) 12 7 6 Total 51 45 13

• Various EUNIS types• >70% of sensitive habitat area

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13 Habitats (& 5 sub types)

(1) Dry heath

(2) Grey Dunes

With variation within EUNIS• A2.54• B1.3/4/5• D1/2• E1.94• F4.2/11• G1.5/6/8

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VSD+ runs

Plan for each habitat: 1. Select a site with average exceedance levels

2. Run 3 Scenarios: – Current Levels– Gothenburg– Background

3. expand number of sites: both a low and high exceedance level

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VSD Parametrization

‘Characteristic’ conditions: Soil parameterization based on SMART-soil types

Vegetation type specific litterfall based on SUMO

Habitat specific seepage and groundwater levels

Site specific soil measurement when available

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Biodiversity endpoint based on policy targets

• List of target (typical) species or • List characteristic species

Favourable status: High quality

- List of competing species

Low quality

Arjen van Hinsberg 08-04-2013

List of species at high Habitat quality

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Calculating Endpoint

Chance of occurrence

Chance of occurrenceMaximum chance

Averaged over species

0

25

50

75

2,5 3,5 4,5 5,5 6,5 7,5

pH

% o

ccur

ence

PROPS for 80% species

Suitability =

Overall Suitability for high quality =

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Examples

Arjen van Hinsberg 08-04-2013

• Plausible trend• Historic situation ok?

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Similar trends at species level

Arjen van Hinsberg 08-04-2013

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Similar trends in more sensitive habitats

Arjen van Hinsberg 08-04-2013

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Overall relationship: Suitability decreases with exceedance

Arjen van Hinsberg 08-04-2013

Each point:

Modelrun of 2050 for a given scenario & habitat

R2 = 0,68

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Response Problems with wetlands, salt wetlands (A2.52), calcareous

soils

3 scenarios runs for 6 habitat types

Various EUNIS types (B1.3/D1,2/F4.2/G1.5,8)

Arjen van Hinsberg 08-04-2013

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Conclusions

Arjen van Hinsberg 08-04-2013

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Conclusions

Methodology works: a representative data set could be delivered– Habitat community could deliver information on targets, maps etc– PROPS available for most (80%) of the ‘high quality’ species– VSD+ can run for different habitat types

Suitability Index for High Quality is useful– Policy relevant, simple & based on targets– Reference is easy– Sensitive for deposition

However: – Ambitions not realized: we didn’t deliver a representative dataset

Arjen van Hinsberg 08-04-2013

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Wishes We need to improve VSD-parameterization and model more

habitat types– wetlands (C, C/N), calcareous soils

We need to improve PROPS with respect to Nitrogen effects– NO3- alone doesn’t tell the hole story

We need better parameterization in historic/low deposition conditions (information from other NFC’s?)

We need to be clear about our model results: – Not only ‘No net loss’ also: high quality– Biological recovery time isn’t modelled!! Often ecological recovery

will be needed.

Arjen van Hinsberg 08-04-2013