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2.2. Mapping of wetland habitats
Dr Giorgos Fotiadis
Agricultural University of Athens
Vegetation types
Being able to differentiate between vegetation types is of high importance, in order to be able to manage them. In the past, many scientists argued about the best way to differentiate vegetation. In 1954, Braun-Blanquet announced a methodology for describing the syntaxonomy of vegetation, which corresponds to the way species are classified in classes, orders, etc., and, at least in Europe, it is now the most widely accepted method for defining the plant communities that make up vegetation types. The differentiation of vegetation types, according to this system, is based on the presence of differential and characteristic (later, diagnostic) species.
Habitat types
In 1992 the European Economic Community created the Natura 2000 network (Habitats Directive 92/43/EEC), a network of protected areas in the European Union. In this directive a list of the habitat types of interest was included for the first time, relating to all European Union countries, and a corresponding manual for their identification was also produced (interpretation manual provided below). The manual sets out the different vegetation types that make up a habitat type, and the mapping of protected areas has subsequently been carried out based on these habitat types. The differentiation between habitat types was based on Braun-Blanquet's method for distinguishing vegetation types, with specific and measurable qualitative and quantitative criteria.
The methodology
In order to differentiate habitat types, vegetation sampling is performed, in which all plant species and their abundance are recorded. After processing the data regarding the presence of plants, the vegetation types, which correspond to habitat types, are obtained (See ‘useful material’, provided below). For example, in order to characterise a type of habitat as a "reedbed", reeds must dominate. If, however, there are some reeds together with some other plant species then it is likely to be another habitat type. What matters is both the dominant species and the combination of a group of species.
Habitat types in Prespa
In Prespa, the recording of habitat types began in the Greek part of the lakes basin, in 2000. In habitat type mapping carried out a decade later, 49 habitat types were found, of which 5 were completely anthropogenic (e.g. arable land), 15 were semi-natural and not protected at European Union level, and 7 were priority habitat types (i.e. of high importance for the European Union). Since 2009, the number of habitat types has been constantly changing, as the instructions on how recognise and describe them have been modified, due to the entry of other countries into the EU, as well as research advances. In 2018, the mapping of habitat types directly affected by Great Prespa Lake in North Macedonia was completed, and in 2019 the respective habitat types in Albania, for both Great and Lesser Prespa lakes, were also mapped. The research revealed new habitat types, as well as describing the pressures and threats (see official catalogue of pressures and threats) that affect them.
Types of habitats around Lesser Prespa Lake in Greece
A total of 9 habitat types have been recorded that are directly affected by Lesser Prespa Lake. 5 of them are habitat types under Directive 92/43/EEC, and 2 of these are priority habitat types, while the other 4 are habitat types that, despite not being registered in the directive, are usually of national interest. The habitat types found are shown in the table below.
Monitoring habitat types
All European Union countries are required to monitor the habitat types of Directive 92/43/EEC every 6 years (habitat types of particular importance to the EU). This monitoring is carried out in order to identify the problems (pressures and threats) that exist from local to national and European level regarding habitat types, in order to take the appropriate management measures for their conservation. In this context, the following are also recorded within the monitoring scheme:
(a) Physiographic data (such as slope and substrate) - for example, there must be a sandy substrate for the 6260 habitat type to be recorded.
(b) Their structure and functions – habitat types such as 91E0 and 92A0 should have a well-developed tree layer, since they are forest habitat types.
(c) Pressures and threats, such as the evolution of vegetation, or the expansion of reedbeds (72A0) to the detriment of habitat type 6420, due to lack of management, for example.
(d) Any possible positive effects, such as restoration actions via a LIFE project.
Useful material:
Enjoy this short video on mapping of wetland habitats.