A species distribution model of the giant kelp Macrocystis pyrifera: Worldwide changes and a focus on the Southeast Pacific

Worldwide climate-driven shifts in the distribution of species is of
special concern when it involves habitat-forming species. In the coastal
environment, large Laminarian algae—kelps—form key coastal ecosystems that
  support complex and   diverse food webs. 
Among kelps, Macrocystis pyrifera is the most widely distributed
habitat-formingspecies and provides essential ecosystem services. This
study aimed to establish the main drivers of  future
distributional changes on a global scale and use them to predict future
habitat suitability. Using species distribution models (SDM), we examined
the changes in  global distribution of M. pyrifera under
 different emission scenarios with a focus on the Southeast
Pacific shores. To constrain the drivers of our simulations to the most
important factors controlling kelp forest distribution across spatial
scales, we explored a suite of environmental variables and validated the
predictions derived from the SDMs. Minimum sea surface temperature was the
single most important variable explaining the global distribution of
suitable habitat for M. pyrifera. Under different climate change
scenarios, we always observed a decrease of suitable habitat at low
latitudes, while an increase was detected in other regions, mostly at high
latitudes. Along the Southeast Pacific, we observed an upper range
contraction of −17.08° S of  latitude for   2090–2100
under the RCP8.5 scenario, implying a loss of habitat suitability
throughout the coast of Peru and poleward to −27.83° S in Chile. Along the
area of  Northern Chile    where  
  a complete habitat loss is  predicted by our model,
natural stands are under heavy exploitation. The loss of habitat
suitability will take place worldwide: Significant impacts on marine
biodiversity and ecosystem functioning are likely. Furthermore, changes in
habitat suitability are a harbinger of massive impacts in the
socio-ecological systems of the Southeast Pacific.