10

 Protection and Conservation of Biodiversity and Ecosystems

Download10

 Protection and Conservation of
Biodiversity and Ecosystems

How does this affect the quality status?

Protecting key features should contribute to the overall quality status

Measures to protect the various species and habitats identified by OSPAR as threatened and/or declining should have a positive benefit for the overall quality status of the marine environment. Although a focus on rare and declining species does not ensure that all key functions of the ecosystem are protected, there will be some benefit to other species, habitats and ecological processes.

In 2009, a re-assessment of the species and habitats listed as threatened and/or declining showed that for most species there had been no change in overall status since their listing in 2003. Some are close to extinction (e.g. Azorean limpet, European sturgeon, Iberian population of the guillemot, northern right whale), many are severely declining (e.g. Balearic shearwater, most diadromous fish species, leatherback turtle), one is now stable but in very low numbers (little shearwater) and one is slightly increasing in numbers (dogwhelk). Stocks of commercially fished species such as bluefin tuna, orange roughy and cod (in parts of the North Sea and Irish Sea) are at a low level. Threats to habitats justifying their inclusion in OSPAR’s List continue. Many of the habitats on the list may still be decreasing in extent and even with the implementation of appropriate measures it will be some time before any improvement can be detected, especially where habitats host long-lived species.

Monitoring and assessing ecosystem health

Although OSPAR countries undertake a wide range of biological monitoring programmes, there is a need for improved coordination. These programmes mostly focus on protected sites or features rather than the functional aspects of the ecosystem. In developing the next phase of OSPAR’s work it will be important to give more emphasis to monitoring and assessing status and impacts at the ecosystem scale. OSPAR’s work on EcoQOs in the North Sea provides a basis for this, for example the EcoQO for healthy seal populations.

Box 10.7 Healthy seal populations

North Sea EcoQO: Taking into account natural population dynamics and trends, there should be no decline in pup production of grey seals or harbour seal population size (as measured by numbers hauled out) of ≥10% as represented in a five-year running mean or point estimates (separated by up to five years) within any one of a set of defined sub-units of the North Sea.

Of the five species of seal that occur in the OSPAR area, only the grey seal and the harbour seal are common in the North Sea (Region II). Separate EcoQOs have been adopted for grey seals and harbour seals to account for their differing biological characteristics. Harbour seals breed more widely around the coast than grey seals, which have breeding colonies in specific locations. In recent decades, virus infections led to high mortality among seals. OSPAR’s EcoQO is to maintain healthy populations of these seal species in the North Sea by triggering management action when needed.

In general, recruitment of grey seal pups in the North Sea increased while the population of harbour seals has decreased over the years up to 2006. Based upon the five years up to 2006 the EcoQO was met for grey seals for all significant units of the North Sea population (see map left). Over the same period, the harbour seal EcoQO was not met in several areas where declines of seals of more than 10% occurred (Shetland, Orkney, east of Scotland, Greater Wash to Scroby Sands, Limfjorden in Denmark, and West Norway) (see map right). Of these areas only the Limfjorden area has been affected by an outbreak of the morbillovirus in recent years. In other areas, the cause of the decline is unknown. Data from 2008 suggest that more recently harbour seal populations in the Wadden Sea have been increasing.

This EcoQO acts as a general ecological indicator, because seals are top predators and their status depends on a wide range of variables. The failure to meet the EcoQO for harbour seals needs to be investigated. Changes in population size or pup recruitment might indicate wider problems in the ecosystem, such as depletion of food stocks through fisheries, pollutants affecting reproductive ability or changes in distribution associated with climate change. A combination of pressures may cause physiological stress and increase susceptibility to disease. If the decline is found to be the result of human activities, then suitable management measures must be implemented.

Evaluation of the EcoQO system for the North Sea

Assessing marine ecosystems that contain a mosaic of different habitats and a diverse range of species is still a challenge. A pilot of a matrix approach to ecosystem assessment is reported in Chapter 11. This provides some useful experience but also reveals that there is a long way to go in order to be able to carry out integrated assessments in a scientifically credible manner. The approach also demonstrates the need for improved methods for monitoring and assessing the extent and condition of habitats. Efforts on habitat classification and mapping must be continued and strengthened, to provide better information on the distribution, extent and condition of habitats in future assessments. There is also an important link to the concept of good environmental status under the EU Marine Strategy Framework Directive, which seeks to embrace eco­system functioning.

Protecting ecosystems beyond MPAs

An ecologically coherent network of well-managed MPAs supports the wider ecosystem. Species and habitats within an MPA depend upon and contribute to processes occurring outside the MPA. These relationships are often more complex and occur over a larger scale than in terrestrial ecosystems and are particularly important for highly mobile species, such as certain seabirds, marine mammals and fish. One of the concepts behind an ecologically coherent network of MPAs is to safe­guard areas critical to certain stages of the lifecycle. A network of MPAs can also provide greater ecosystem resilience in response to changing environmental conditions, such as climate change. Monitoring within MPAs needs to be extended to allow evaluation of whether OSPAR MPAs have improved the status of the local or the wider environment.