1. Methods to quantify human effects on marine ecosystems
Samuli Korpinen
OSPAR ICG-C, IJmuiden

2. The review of the three methods
Familiarizing with the methods
Making criteria for a comparison
1. Scientific credibility: pressures, ecosystem components, impacts
2. Spatial resolution and flexibility
3. Flexibility in data formats
4. Transparency
5. Clarity
6. Temporal aspect
7. Flexibility for different purposes
8. Efficacy of the method
Analyzing differences
Finding similarities
Potential to merge the methods

3. 1. The HARMONY method , where: P: a pressure (scoring 0-1),
E: an ecosystem or its component (scoring 0-1),
μ: an impact score for each PxE combination (scoring 0-4)
Halpern et al. 2008

4. Figure 3. The human footprint, a quantitative evaluation of human influence on the land surface, based on geographic data describing human population density, land transformation, access, and electrical power infrastructure, and normalized to reflect the continuum of human influence across each terrestrial biome defined within biogeographic realms. Further views and additional information are available at “Atlas of the Human Footprint” Web site, Data are available at National boundaries are not authoritative.
Sanderson E W et al. BioScience 2002;52:
© 2002 American Institute of Biological Sciences

5. Baltic Sea Impact Index + North Sea Impact Index
Regional adaptations:
A web survey for the effect scores, incl. a self assessment of own expertise.
Spatial extent of effect was estimated by the web survey.
Habitat presence 0/1 but species presence by probability (0-1).
A software (impact mapper) was made:
Calculates an activity index, pressure index and impact index;
Calculates potential impacts for selected activities or ecosystem components.
HELCOM 2010, Korpinen et al. 2012
For different ecosystem components
Andersen et al. 2013

6. 2. The CUMULEO method The method briefly:
The oldest of the three methods  several versions published.
The only method which uses data-driven estimates for impacts.
E.g. CUMULEO-RAM where effects are linked to species productivity.
Van der Wal & Tamis 2014: effect is estimated as habitat loss (%).
DeVries et al. 2011

7. 3. The ODEMM method
Linkage framework: activities – pressures – ecosystem ( impact chain).
Counts the number of acute impacts.
Takes account of ’combined impacts’  two chronic impacts in a same area become an acute one.

8. Comparison of the methods
CUMULEO
HARMONY
ODEMM
Pressure GIS data
(Habitat loss, km2)
Ecosystem GIS data (species diversity/group)
Pressure GIS data
(intensity 0-1)
Ecosystem GIS data (presence 0-1)
Pressure GIS data
(presence 0/1)
Ecosystem GIS data (presence 0/1)
PRESSURE DATA
Assessment area divided to units (e.g. grid cells).
Pressures defined.
Spatial data covers the entire assessment area.
Differences:
CUMULEO + HARMONY: intensity;
ODEMM: presence/absence.
ECOSYSTEM DATA
Components defined.
Spatial data covers the entire assessment area.
Presence/absence
Differences:
HARMONY: probability of occurrence;
CUMULEO: weighting of data.

9. Comparison of the methods
CUMULEO
HARMONY
ODEMM
Pressure GIS data
(Habitat loss, km2)
Ecosystem GIS data (species diversity/group)
Pressure GIS data
(intensity 0-1)
Ecosystem GIS data (presence 0-1)
Pressure GIS data
(presence 0/1)
Ecosystem GIS data (presence 0/1)
Impact score
0-1: consisting of studied impact on habitat use
Impact score
0-1: consisting of impact level, impact extent, recovery time
Degree of impact: low, chronic, acute
Recovery time: low, moderate, high, severe
CUMULEO IMPACT SCORES
Impacts from studies
E.g. how much habitat is lost? How much fish stock is caught? Etc.
Normalized to 0-1 scale.
HARMONY IMPACT SCORES
Impacts from expert judgment, 0-4 scale.
The score is the mean of three criteria:
impact extent,
recovery time
impact level
Also a weighted mean
Confidence estimate
ODEMM IMPACT SCORES
Categorical: Low, Chronic, Acute
Only acute pressures are counted.
If a pressure is caused by two different activities  2 (or more) chronic become acute  ’combined impact’.

10. Comparison of the methods
The main difference is that HARMONY and CUMULEO calculate ’cumulative effects’ but ODEMM calculates ’the number of effecting pressures’.
A sligthly similar approach was used in HELCOM holistic assessment:

11. Testing the robustness of the index
9 scenarios: 3 random pressure data sets and 3 random ecosystem data sets

12. Testing the robustness of the index
3 impact scores: expert given, random and equal
We also tested how much the impact scores affect if there is fewer data in the index. The result was clear: the impact scores have a stronger effect with fewer pressure data sets.

13. Cumulative effects
Crain et al. 2008
ANTAGONISTIC
ADDITIVE
SYNERGISTIC

14. Linkage with the state of the sea?
Halpern et al. 2008
Percent degradation
Andersson et al. 2015