Distribution shifts of marine species

Assessment versions

Published (reviewed and quality assured)

• No published assessments

Rationale

Justification for indicator selection

Most marine organisms are ‘ectotherms’ that rely on the temperature of their environment to function optimally and are adapted to the temperature regime of their existing distribution range. Because of this relationship between the physical environment and species’ life requirements, the redistribution of species has emerged as one of the most significant and visible species responses to climate change.

Climate velocities (the rate and direction that isotherms shift through space) can be up to seven times higher in the ocean than on land. Combined with fewer dispersal barriers in the marine environment, this allows marine species to seek out optimal temperature regimes faster than most terrestrial species. Changes in species distribution can therefore be used as an indicator of climate change impacts in marine ecosystems, bridging the gap between observed changes in physical conditions of the sea and observed changes in biological parameters.

As the distribution and abundance of a species changes, so will the role of that particular species in the local or regional marine community. Changes in species distribution can, in turn, change the overall productivity and stability of the local ecosystem, thereby ultimately affecting the food available to (other) fish, birds and marine mammals.

Changes in species distribution will also create challenges for local communities that depend on fish stocks and other marine resources. For example, the recent mackerel dispute between the EU and the Faroe Islands was caused by the fact that the mackerel stock had increased the time it spent in the waters of the Faroe Islands rather than in EU waters. This caused a heated discussion on stock allocation between countries. Ultimately, it led to an increase in the Faroe Islands’ total allowable catch from 5 to 13 %, with further increases planned. Such disputes will most likely occur again as coldwater species retreat northwards. New opportunities may arise as new species come in from the south, but it is uncertain whether these will be of a similar commercial value to the receding ones.

In addition to changes in species distribution, rising sea surface temperatures are also causing changes in the phenology of marine species.

Scientific references

• No rationale references available

Indicator definition

• Ratio of Calanus species in the Greater North Sea
• Observed change in the distribution of demersal fish in response to the observed rise in sea surface temperature

Units

• Ratio (dimensionless)

• Abundance response to temperature (dimensionless)

Policy context and targets

Context description

In April 2013, the European Commission (EC) presented the EU Adaptation Strategy Package. This package consists of the EU Strategy on adaptation to climate change (COM/2013/216 final) and a number of supporting documents. The overall aim of the EU Adaptation Strategy is to contribute to a more climate-resilient Europe.

One of the objectives of the EU Adaptation Strategy is Better informed decision-making, which will be achieved by bridging the knowledge gap and further developing the European climate adaptation platform (Climate-ADAPT) as the ‘one-stop shop’ for adaptation information in Europe. Climate-ADAPT has been developed jointly by the EC and the EEA to share knowledge on (1) observed and projected climate change and its impacts on environmental and social systems and on human health, (2) relevant research, (3) EU, transnational, national and subnational adaptation strategies and plans, and (4) adaptation case studies.

Further objectives include Promoting adaptation in key vulnerablesectors through climate-proofing EU sector policies and Promoting action by Member States. Most EU Member States have already adopted national adaptation strategies and many have also prepared action plans on climate change adaptation. The EC also supports adaptation in cities through the Covenant of Mayors for Climate and Energy initiative.

In September 2016, the EC presented an indicative roadmap for the evaluation of the EU Adaptation Strategy by 2018.

In November 2013, the European Parliament and the European Council adopted the 7^th EU Environment Action Programme (7^th EAP) to 2020, ‘Living well, within the limits of our planet’. The 7^th EAP is intended to help guide EU action on environment and climate change up to and beyond 2020. It highlights that ‘Action to mitigate and adapt to climate change will increase the resilience of the Union’s economy and society, while stimulating innovation and protecting the Union’s natural resources.’ Consequently, several priority objectives of the 7^th EAP refer to climate change adaptation.

Targets

No targets have been specified.

Related policy documents

• 7th Environment Action Programme
  DECISION No 1386/2013/EU OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 20 November 2013 on a General Union Environment Action Programme to 2020 ‘Living well, within the limits of our planet’. In November 2013, the European Parliament and the European Council adopted the 7 th EU Environment Action Programme to 2020 ‘Living well, within the limits of our planet’. This programme is intended to help guide EU action on the environment and climate change up to and beyond 2020 based on the following vision: ‘In 2050, we live well, within the planet’s ecological limits. Our prosperity and healthy environment stem from an innovative, circular economy where nothing is wasted and where natural resources are managed sustainably, and biodiversity is protected, valued and restored in ways that enhance our society’s resilience. Our low-carbon growth has long been decoupled from resource use, setting the pace for a safe and sustainable global society.’
• Climate-ADAPT: Adaptation in EU policy sectors
  Overview of EU sector policies in which mainstreaming of adaptation to climate change is ongoing or explored
• Climate-ADAPT: Country profiles
  Overview of activities of EEA member countries in preparing, developing and implementing adaptation strategies
• DG CLIMA: Adaptation to climate change
  Adaptation means anticipating the adverse effects of climate change and taking appropriate action to prevent or minimise the damage they can cause, or taking advantage of opportunities that may arise. It has been shown that well planned, early adaptation action saves money and lives in the future. This web portal provides information on all adaptation activities of the European Commission.
• EU Adaptation Strategy Package
  In April 2013, the European Commission adopted an EU strategy on adaptation to climate change, which has been welcomed by the EU Member States. The strategy aims to make Europe more climate-resilient. By taking a coherent approach and providing for improved coordination, it enhances the preparedness and capacity of all governance levels to respond to the impacts of climate change.

Methodology

Methodology for indicator calculation

Data from the Sir Alister Hardy Foundation for Ocean Science (SAHFOS) on Calanus abundance in the central North Sea since 1958 is used for the indicator. The Continuous Plankton Recorder (CPR) survey is the longest running, large-scale marine biological survey in the world. The CPR is a near-surface (10 m) plankton sampler voluntarily towed each month behind merchant ships on their normal routes of passage. Methods of analysis for 400 phyto and zooplankton taxa have remained almost unchanged since 1958.

The effects of temperature variability on abundance of demersal species within the European continental shelf fish assemblage has been investigated through compiling and analysing three decades of high-resolution data

Methodology for gap filling

Not applicable

Methodology references

No methodology references available.

Data specifications

EEA data references

• No datasets have been specified here.

External data references

• Demersal survey data - supplementary dataset S2
• Monthly mean graphs for CPR standard areas (dataset URL is not available)

Data sources in latest figures

Uncertainties

Methodology uncertainty

See under "Methodology".

Data sets uncertainty

In general, changes related to the physical and chemical marine environment are better documented than biological changes. For example, systematic observations of sea surface temperature began around 1880. In contrast, the longest available time series of plankton from the Continuous Plankton Recorder (CPR) is around 60 years. Sampling was started in the North Sea in the 1950s and today a network covering the entire North Atlantic Ocean has been established.

Our understanding is improving of how climate change, in combination with the synergistic impacts of other stressors, can cause regime shifts in marine ecosystems, but additional research is still needed to untangle the complex interactions and their effects upon biodiversity. Ecological thresholds for individual species are still only understood in hindsight, i.e. once a change has occurred.

Rationale uncertainty

No uncertainty has been specified