De Clerck, O.

Everaert, G.

Pirlet, H.

Vandegehuchte, M.

Westmeijer, G.

Open Marine Archive

 31 
Habitat suitability modelling of macroalgae with a mechanistic 
approach 
Westmeijer George
1
, Everaert Gert
1
, Pirlet Hans
1
, De Clerck Olivier
2
 and Vandegehuchte Michiel
2 
1 
Flanders Marine Institute (VLIZ), InnovOcean site, Wandelaarkaai 7, 8400 Ostend, Belgium 
 E-mail: george.westmeijer@vliz.be 
2
  Phycology Research Group, Biology Department, Ghent University, Krijgslaan 281 (S8), 9000 
Ghent, Belgium 
 
Intertidal, macroalgal species in the North-Atlantic are vulnerable to climate change and species that 
lack an adaptive capacity to the rising temperatures will either go extinct of migrate north to a more 
suitable habitat. Many intertidal macroalgae function as ecosystem engineer, a range shift therefore 
has the potential to disturb the intertidal community and to initiate changes that resonate throughout 
the entire marine ecosystem. To assess a potential range shift of macroalgae, their habitat suitability 
in the European marine environment was predicted, as well as the evolution of this habitat suitability 
by 2100. To predict the habitat suitability, we used a mechanistic model comprising physiological 
optima and –thresholds, reported in literature, and applied this model to environmental data. 
Variables included in the mechanistic model are sea surface temperature, surface salinity, 
photosynthetically active radiation, nitrate concentration, turbidity and surface temperature of the 
warmest month. Using a mechanistic model enables to do predictions outside the environmental 
range where the species is presently distributed. This is highly relevant for climate change scenarios. 
The model was validated by comparing the predicted habitat suitability with distribution records from 
the Global Biodiversity Information Facility. For example, for the red algae Chondrus crispus, no 
presences were recorded on locations with a low habitat suitability (< 0.4). Most presences (> 85%) 
corresponded with a high predicted habitat suitability (> 0.6). Climate change was modelled by using 
the Representative Concentration Pathways (RCP), adopted by the Intergovernmental Panel on Climate 
Change. For Chondrus crispus the most optimal habitat is predicted to migrate 160 km north by 2100 
under the most optimistic climate change scenario, RCP 2.6. This migration is 375 kilometers by 2100 
under the more pessimistic climate change scenario, RCP 6.0. 
 
The results of this research may aid in the decision making process on the location for the aquaculture 
of certain seaweed species. To make the habitat suitability map relevant for aquacultural purposes, 
spatial planning of the marine environment was added to the model and the depth of the water 
column was taken into account. Eight macroalgae were modelled so far but this selection is likely to 
expand in the near future. 
 
Keywords: mechanistic modelling; physiological thresholds; species distribution models; climate 
change; marine macroalgae; Chondrus crispus 


Habitat suitability modelling of macroalgae with a mechanistic approach

http://www.vliz.be/imisdocs/publications/311858.pdf

Habitat suitability modelling of macroalgae with a mechanistic approach

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