EPA research on the diversity and resilience of Kelp Forests on Irish coasts

New research by the EPA cautions against wild harvesting of kelp and recommends more monitoring

As we head towards Ireland’s coasts over the coming weeks we are likely to come across kelp fragments along the shore. In Ireland, kelp dominates rocky substrata along moderately exposed coastline (approximately 3010 km out of the 7524 km of national shoreline). Kelps are large brown seaweeds within the order Laminariales that contribute to understorey and over-storey canopies in intertidal and subtidal habitats worldwide. Kelp presence depends on light availability, sea surface temperature (SST) and the presence of bedrock to act as a substrate.

Kelp species provide marine habitats, are primary producers and store organic carbon, foster biodiversity, and are valuable from an Ecosystem Services perspective. These ecosystems provide protection of coastal habitats via physical attenuation of wave action, food web and ecosystem structuring, and recreational activities.

Threats faced by kelp species include ocean warming and marine heat waves, overgrazing by herbivores, eutrophication and sedimentation, wild harvesting of kelp forests and increased storm activity. They are susceptible to anthropogenic disturbances and climate change, making the investigation of kelp’s potential resilience pertinent for the protection of this natural resource.

We have little understanding of kelp forest food webs in Ireland, such as how kelp contributes carbon to food chains, which fisheries rely on kelp for subsistence or habitat, and what functional redundancy exists in kelp communities to buffer them from the effects of climate change or “fishing down food webs”. Furthermore, we have no accurate measure of how much kelp exists in Ireland, or of its distribution across depths, along coasts and over seasons. Gathering these data would require a more intensive monitoring and field programme.

While some monitoring started in the west of Ireland in 2016, very little is know about Ireland’s kelp habitats. More information is needed to create ecological baselines for these habitats to measure and track change in these communities, to better estimate the Ecosystem Services they provide and how they add to nature’s contribution to people, and to understand how these natural resources respond to disturbance. The ability to recover from threats can be termed “resilience”, defined as the ability of an ecosystem to recover and maintain normal ecological function after a disturbance event.

A recently published EPA report  on kelp ecosystem diversity and resilience does not recommend wild harvesting of kelp in Ireland, in order to protect help habitats particularly as no routine monitoring takes place, it would be impossible to ensure that wild kelp harvesting is sustainable and that populations would recover. There is no tried-and-tested method for repairing or restoring these systems after they collapse. Therefore, the approach to their management in Ireland should be cautious. Hand in hand with protecting kelp resources is the need to conduct monitoring.

The Research Report is available at:

Research-_Report_413.pdf (epa.ie)

Kelp Forest Infographic

Communicating research | Environmental Protection Agency (epa.ie)

 

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