D1 Biological Diversity
Biological diversity is maintained. The quality and occurrence of habitats and the distribution and abundance of species are in line with prevailing physiographic, geographic and climatic conditions.
Descriptor 1 of the MSFD is providing a definition of Good Environmental Status in relation to biological diversity. This equates to a state where there is no further loss of diversity, the deteriorated attributes of biological diversity are restored and the use of the marine environment is sustainable. The assessment of state is required at three main ecological levels: species, habitats and ecosystems.
The definition is in line with the objectives of the EU biodiversity strategy to 2020 and its implementation is directly linked to the Birds and Habitats Directives. Indirect links exist with other environmental policies tackling pollution from various sources (e.g. Water Framework Directive, the Habitats Directive, Birds Directive), the Common Fisheries Policy (CFP) and the new EU regulation on Invasive Alien Species (IAS).
© Fotolia, Author: Christian Colista
According to the Marine Strategy Framework Directive (MSFD), biological diversity should be maintained. Specifically, the quality and occurrence of habitats and the distribution and abundance of species are in line with prevailing physiographic, geographic and climatic conditions. The Directive covers the whole range of species, habitats and associated pressures in all European marine regions (from coastal waters to open seas). The COM Decision sets certain criteria and indicators to define Good Environmental Status (GES) on species, population, habitat and ecosystem level. It is widely recognized that there are links between D1 (biodiversity per se), D4 (food-webs) and D6 (sea-floor integrity) and these are frequently referred together as the 'biodiversity theme' since the data and information requirements for these Descriptors overlap to a considerable degree, although there are separate description of what GES is for each one of them. It is also recognized that although aspects of these Descriptors are, to some extent, already addressed by other EU pieces of legislation the MSFD implementation requires further scientific and technical developments to better set the conceptual frame of biodiversity, define GES, set meaningful targets and achieve an operational capacity for a meaningful monitoring and assessment.
Biological diversity is maintained. The quality and occurrence of habitats and the distribution and abundance of species are in line with prevailing physiographic, geographic and climate conditions.
Assessment is required at several ecological levels: ecosystems, habitats (including their associated communities, in the sense of biotopes) and species, which are reflected in the structure of this section, taking into account point 2 of Part A. For certain aspects of this descriptor, additional scientific and technical support is required ( 5 ). To address the broad scope of the descriptor, it is necessary, having regard to Annex III to Directive 2008/56/EC, to prioritise among biodiversity features at the level of species, habitats and ecosystems. This enables the identification of those biodiversity features and those areas where impacts and threats arise and also supports the identification of appropriate indicators among the selected criteria, adequate to the areas and the features concerned ( 6 ). The obligation of regional cooperation contained in Articles 5 and 6 of Directive 2008/56/EC is directly relevant to the process of selection of biodiversity features within regions, sub-regions and subdivisions, including for the establishment, where appropriate, of reference conditions pursuant to Annex IV to Directive 2008/56/EC. Modelling using a geographic information system platform may provide a useful basis for mapping a range of biodiversity features and human activities and their pressures, provided that any errors involved are properly assessed and described when applying the results. This type of data is a prerequisite for ecosystem-based management of human activities and for developing related spatial tools ( 7 ).
For each region, sub-region or subdivision, taking into account the different species and communities (e.g. for phytoplankton and zooplankton) contained in the indicative list in Table 1 of Annex III to Directive 2008/56/EC, it is necessary to draw up a set of relevant species and functional groups, having regard to point 2 of Part A. The three criteria for the assessment of any species are species distribution, population size and population condition. As to the later, there are cases where it also entails an understanding of population health and inter- and intra-specific relationships. It is also necessary to assess separately subspecies and populations where the initial assessment, or new information available, identifies impacts and potential threats to the status of some of them. The assessment of species also requires an integrated understanding of the distribution, extent and condition of their habitats, coherent with the requirements laid down in Directive 92/43/EEC ( 8 ) and Directive 2009/147/EC, to make sure that there is a sufficiently large habitat to maintain its population, taking into consideration any threat of deterioration or loss of such habitats. In relation to biodiversity at the level of species, the three criteria for assessing progress towards good environmental status, as well as the indicators related respectively to them, are the following:
- Distributional range (1.1.1)
- Distributional pattern within the latter, where appropriate (1.1.2)
- Area covered by the species (for sessile/benthic species) (1.1.3)
- Population abundance and/or biomass, as appropriate (1.2.1)
- Population demographic characteristics (e.g. body size or age class structure, sex ratio, fecundity rates, survival/ mortality rates) (1.3.1)
- Population genetic structure, where appropriate (1.3.2).
For the purpose of Directive 2008/56/EC, the term habitat addresses both the abiotic characteristics and the associated biological community, treating both elements together in the sense of the term biotope. A set of habitat types needs to be drawn up for each region, sub-region or subdivision, taking into account the different habitats contained in the indicative list in Table 1 of Annex III and having regard to the instruments mentioned in point 2 of Part A. Such instruments also refer to a number of habitat complexes (which means assessing, where appropriate, the composition, extent and relative proportions of habitats within such complexes) and to functional habitats (such as spawning, breeding and feeding areas and migration routes). Additional efforts for a coherent classification of marine habitats, supported by adequate mapping, are essential for assessment at habitat level, taking also into account variations along the gradient of distance from the coast and depth (e.g. coastal, shelf and deep sea). The three criteria for the assessment of habitats are their distribution, extent and condition (for the latter, in particular the condition of typical species and communities), accompanied with the indicators related respectively to them. The assessment of habitat condition requires an integrated understanding of the status of associated communities and species, coherent with the requirements laid down in Directive 92/43/EEC ( 9 ) and Directive 2009/147/EC, including where appropriate an assessment of their functional traits.
- Distributional range (1.4.1)
- Distributional pattern (1.4.2)
- Habitat area (1.5.1)
- Habitat volume, where relevant (1.5.2)
- Condition of the typical species and communities (1.6.1)
- Relative abundance and/or biomass, as appropriate (1.6.2)
- Physical, hydrological and chemical conditions (1.6.3).
- Composition and relative proportions of ecosystem components (habitats and species) (1.7.1).
In addition, the interactions between the structural components of the ecosystem are fundamental for assessing ecosystem processes and functions for the purpose of the overall determination of good environmental status, having regard, inter alia, to Articles 1, 3(5) and 9(1) of Directive 2008/56/EC. Other functional aspects addressed through other descriptors of good environmental status (such as descriptors 4 and 6), as well as connectivity and resilience considerations, are also important for addressing ecosystem processes and functions.
According to the TG1 report:
Descriptor 1: "Biological diversity is maintained. The quality and occurrence of habitats and the distribution and abundance of species are in line with prevailing physiographic, geographic and climatic conditions". See Sections 0 and 2.1.
Biological diversity, in accordance with the Convention on Biological Diversity (CBD, 1992), is defined as 'the variability among living organisms from all sources including, inter alia, [terrestrial,] marine [and other aquatic ecosystems] and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems'.
Maintained equates to:
a) no further loss of the diversity within species, between species and of habitats/communities and ecosystems at ecologically relevant scales,
b) any deteriorated attributes of biological diversity are restored to and maintained at or above target levels, where intrinsic conditions allow (cf. Art. 1.2a) and
c) where the use of the marine environment is sustainable.
The term 'habitat' in this Descriptor addresses both the abiotic characteristics and the associated biological community, treating both elements together in the sense of the term biotope (COM DEC 2010/477/EU), whereas 'quality', 'occurrence', 'distribution', 'extent' and 'abundance' form the basis of the criteria standards used to assess GES.