14
Possible Causes of Poor Transferability
Objects of Interest Differ (Even if They Carry the Same Name)
Biodiversity is extremely diverse, as are the stakeholders in biodiversity conservation and the (living) objects they are studying, monitoring and/or conserving.
Although designated by the same name, objects may actually be extremely variable
across Europe or even globally, and therefore hard to define. Forest, for instance, is
a widely used and intuitively understood term, but the variation in national forest
definitions is huge, with different thresholds applied for crown closure, tree height,
minimum area and minimum width (Lawrence et al. 2010). As a result, what is
considered a forest in one country, may not classify as a forest in a neighbouring
country, or vice versa.
Natura 2000 habitat types provide another example of different definitions under
the same name. Although this typology is embedded in European legislation, guidance from the EU on the identification of the different habitat types has been rather
limited and biased towards regions with pre-existing vegetation typologies (UK,
Germany, Nordic countries) at the time when the list was drawn up (Evans 2006).
As a result, most member states produced their own national interpretation handbooks for the habitat types on their territory, with varying levels of agreement
between states. To illustrate this variation, we screened a selection of these handbooks (see Annex) for the national definitions of two rather widespread habitat
types; the ‘European dry heaths’ (Natura 2000 code: 4030) (45 descriptive definitions of the type or subtypes found, in 18 different sources, from 10 member states)
and ‘Luzulo-Fagetum beech forests’ (Natura 2000 code: 9110) (19 descriptions, 16
sources, 8 member states), We noted the plant species mentioned as ‘characteristic’,
‘typical’, ‘indicative’, or similar wordings. Looking at these species lists, the extent
of the variation (or the difference in interpretation) becomes immediately obvious
(Fig. 1). The vast majority (68%) of species were mentioned only once or twice. Of
the 219 vascular plant species and 37 lichens and mosses typical of ‘European dry
heaths’, only eleven vascular plant species (i.e., 5%) and one moss were mentioned
in more than a quarter of the descriptions. For the ‘Luzulo-Fagetum beech forests’,
the species list is somewhat more uniform, with 23 out of 90 vascular plants (26%)
and three out of nine mosses mentioned in more than a quarter of the habitat descriptions. The low agreement in component species is partly due to different ecological
characteristics of the habitat across Europe. However, different interpretations
between member states, and even between regions within a member state, undoubtedly also play a role (Evans, 2010).
J. Vanden Borre et al.
Possible Causes of Poor Transferability
Objects of Interest Differ (Even if They Carry the Same Name)
Biodiversity is extremely diverse, as are the stakeholders in biodiversity conservation and the (living) objects they are studying, monitoring and/or conserving.
Although designated by the same name, objects may actually be extremely variable
across Europe or even globally, and therefore hard to define. Forest, for instance, is
a widely used and intuitively understood term, but the variation in national forest
definitions is huge, with different thresholds applied for crown closure, tree height,
minimum area and minimum width (Lawrence et al. 2010). As a result, what is
considered a forest in one country, may not classify as a forest in a neighbouring
country, or vice versa.
Natura 2000 habitat types provide another example of different definitions under
the same name. Although this typology is embedded in European legislation, guidance from the EU on the identification of the different habitat types has been rather
limited and biased towards regions with pre-existing vegetation typologies (UK,
Germany, Nordic countries) at the time when the list was drawn up (Evans 2006).
As a result, most member states produced their own national interpretation handbooks for the habitat types on their territory, with varying levels of agreement
between states. To illustrate this variation, we screened a selection of these handbooks (see Annex) for the national definitions of two rather widespread habitat
types; the ‘European dry heaths’ (Natura 2000 code: 4030) (45 descriptive definitions of the type or subtypes found, in 18 different sources, from 10 member states)
and ‘Luzulo-Fagetum beech forests’ (Natura 2000 code: 9110) (19 descriptions, 16
sources, 8 member states), We noted the plant species mentioned as ‘characteristic’,
‘typical’, ‘indicative’, or similar wordings. Looking at these species lists, the extent
of the variation (or the difference in interpretation) becomes immediately obvious
(Fig. 1). The vast majority (68%) of species were mentioned only once or twice. Of
the 219 vascular plant species and 37 lichens and mosses typical of ‘European dry
heaths’, only eleven vascular plant species (i.e., 5%) and one moss were mentioned
in more than a quarter of the descriptions. For the ‘Luzulo-Fagetum beech forests’,
the species list is somewhat more uniform, with 23 out of 90 vascular plants (26%)
and three out of nine mosses mentioned in more than a quarter of the habitat descriptions. The low agreement in component species is partly due to different ecological
characteristics of the habitat across Europe. However, different interpretations
between member states, and even between regions within a member state, undoubtedly also play a role (Evans, 2010).
J. Vanden Borre et al.