5 Natura 2000 and conservation status
5.3 Trends and conservation status of species and habitat types
In this section, the habitats and species assessments have been divided into three groups based on percentage cover by Natura 2000: > 75%, 35% to 75% and < 35%. These classes were chosen using a statistical technique (k-medoids) which is designed to divide data into homogeneous groups.
Member State rather than EU regional assessments were used to investigate potential relationships between coverage by Natura 2000 and conservation status or trends, as they are more closely connected.
The total population sizes and population sizes within the Natura 2000 sites per biogeographical region are frequently missing due to use of differing population units by Member States (see Section 3.4.6).
There is no significant association (chi-squared test) between habitats, conservation status and Natura 2000 coverage classes (see Figure 5.6). For habitats assessed as unfavourable, Natura 2000 coverage was significantly associated with the trend in conservation status (see Figure 5.7). The proportion of habitats assessments with declining unfavourable conservation status is higher in the 0–35% class than in the 75–100%
class.
The proportion of assessments with stable trends is relatively higher in the 75%-to-100% class. Similar results were obtained using analysis of variance (ANOVA), where habitats assessed as unfavourable whose trend (qualifier) is stable or improving have a higher coverage (mean = 61%) than unfavourable habitats which are deteriorating (mean = 53%).
Similar results were obtained when analysing association between the coverage and trends in
conservation status using EU biogeographical data (coverage by Natura 2000 in EU biogeographical regions and EU biogeographical trends in conservation status). Habitats with positive or equal qualifiers have significantly higher (P = 0.002) coverage in Natura 2000 sites (mean = 60%) than habitats with a negative conclusion qualifier (mean = 53%).
Where Member States used the same unit for both an overall species population and the share of this population included in Natura 2000, it is possible to calculate the coverage by Natura 2000 at a national scale and to compare it with conservation status and trends, since these are always ratios. As for habitats, there is no significant association (tested by chi-squared test) between conservation status of Annex II species and Natura 2000 coverage classes (see Figure 5.8). However, for species assessed as unfavourable, Natura 2000 coverage was significantly associated with the trend in conservation status (see Figure 5.9) and also with the short‑term population trend (see Figure 5.10).
Figure 5.6 Conservation status (Member State assessments) of Annex I habitats with
> 75%, 35–75% and < 35% of their area covered by Natura 2000
Source: EEA, 2015b, Article 17 reports and assessments.
Source: EEA, 2015b, Article 17 reports and assessments.
Source: EEA, 2015b, Article 17 reports and assessments.
0% 20% 40% 60% 80% 100%
0–35% (690) 35–75% (824) 75–100% (1 152)
Favourable Unknown
Unfavourable-inadequate Unfavourable-bad
Figure 5.7 Trends in conservation status of Annex I habitats assessed by Member State as unfavourable with > 75%, 35–
75% and < 35% of their area covered by Natura 2000
0% 20% 40% 60% 80% 100%
0–35% (485) 35–75% (606) 75–100% (799)
Unfavourable-improving Unfavourable-unknown-trend
Unfavourable-stable Unfavourable-declining
Figure 5.8 Conservation status (Member State assessments) of Annex II species with
> 75%, 35–75% and < 35% of their population covered by Natura 2000
Favourable Unknown
Unfavourable-inadequate Unfavourable-bad
0% 20% 40% 60% 80% 100%
0-35% (828) 35-75% (758) 75-100% (1 401)
Source: EEA, 2015b, Article 17 reports and assessments.
Source: EEA, 2015b, Article 17 reports and assessments.
The proportion of species assessments with decreasing population trends (see Figure 5.10) or declining
unfavourable conservation status (see Figure 5.9) is higher in the 0–35% class than in the 75–100% class.
The proportion of assessments with stable trends is relatively higher in the 75–100% class.
Figure 5.9 Trends in conservation status of Annex II species assessed as unfavourable with > 75%, 35%–75%
and < 35% of their population covered by Natura 2000
0% 20% 40% 60% 80% 100%
0–35% (524) 35–75% (495) 75–100% (942)
Unfavourable-improving Unfavourable-unknown-trend
Unfavourable-stable Unfavourable-declining
Figure 5.10 Short-term population trends of Annex II species with > 75%, 35%–75%
and < 35% of their population covered by Natura 2000
0% 20% 40% 60% 80% 100%
0–35% (828) 35–75% (758) 75–100% (1 401)
Increasing Stable Unknown Decreasing
Similar patterns were obtained using ANOVA, where species assessed as unfavourable whose trend (qualifier) is stable and improving have a higher coverage (mean for stable trend = 60%, mean for improving trend = 54%) than unfavourable species which are declining (mean = 44%). The long‑term population trend was optional and the data too incomplete to allow any analysis.
At the EU biogeographical level this type of analysis was not possible, as data from Member States do not allow estimates of population size or of the population within the Natura 2000 network at the biogeographical scale.
But analyses based on a GIS approach (see Section 4.2.2 above) revealed similar association between the coverage and trends in conservation status. Species with positive or equal conclusion qualifiers have significantly higher (P = 0.012) coverage in Natura 2000 sites (mean = 71%) than species with a negative conclusion qualifier (mean = 67%).
For Annex I bird species, there is no significant association (tested by chi-squared test) between species short-term population trend and Natura 2000 coverage classes (see Figure 5.11). However, for the non‑Annex I SPA trigger species, the Natura 2000 coverage class is significantly associated with the population trend. The species in the lowest coverage class (0–35%) seem more likely to have decreasing population trends than species in the other coverage classes (35–75%, and 75–100%). The frequency of stable population trend in the highest coverage class (57–100%) is higher than expected, and similarly the frequency of increasing trends is higher than expected in the middle coverage class (35–75%).
Similar types of findings concerning non-SPA trigger species were made as part of a survey carried out by Pellissier et al. (2013) when analysing the impacts of Natura 2000 on common bird (and butterflies) species, based on data from national or regional monitoring (see Box 5.1).
Figure 5.11 Short-term population trends of SPA trigger bird species listed in Annex I (Birds Directive) (left) and not listed in Annex I (right) with > 75%, 35%–75% and < 35% of their population covered by Natura 2000
Source: EEA, 2015a, Article 12 reports and assessments.
0% 20% 40% 60% 80% 100%
0–35% (580) 35–75% (463) 75–100% (477)
0% 20% 40% 60% 80% 100%
0–35% (273) 35–75% (268) 75–100% (283)
Increasing Stable/fluctuating Unknown Decreasing
The associations noted above between the trends and Natura 2000 coverage suggest that in many situations, Natura 2000 could play a role in stabilising trends and preventing further decline. The Habitats Directive concept of conservation status is complex, involving several components. Beside trends in range and population/area, it also incorporates distance to a target state (given by the favourable reference values) and requires considerable change before any improvement in conservation status. This could be a reason for the apparent lack of association between the conservation status and the Natura 2000 coverage observed. It may also be that many habitats and species require many years, maybe decades, to recover, due to conservation measures.
Only species listed in Annex II of the Habitats Directive are subject to the designation of Natura 2000 sites, so only these species can directly benefit from site designation and associated measures (non-target species can benefit indirectly — see Section 4.6 below). Annex II species have a lower proportion of EU regional assessments as favourable (22%), but
Figure 5.12 Conservation status and trends for Annex II (left) and non-Annex II (right) species
Source: EEA, 2015b, Article 17 reports and assessments.
26%
26%
37%
11%
Non-Annex II species 22%
12%
44%
22%
Annex II species
Favourable Unknown Unfavourable-inadequate Unfavourable-bad
higher proportions as unfavourable-inadequate and unfavourable-bad (44% and 22%) in comparison with the non‑Annex II species (see Figure 5.12). However, it must be kept in mind that more than a quarter of assessments of Annex II species are unknown.
Regarding trends in conservation status, a higher proportion of Annex II species have unfavourable‑
improving or unfavourable-stable status, in comparison to non‑Annex II species (49% compared to 44%), but also, a higher proportion of Annex II species have an unfavourable-deteriorating trend (24% compared to 17%) (see Figure 5.13).
The list of SPA classification triggering species are specific for each Member State. Listing the species as an SPA trigger-species does not seem to have an important influence on its population trends, when comparing population trends between Member States where the species is listed as the SPA trigger and Member States where the species is not listed as such (see Figure 5.14).
However, the proportion of species populations with increasing population trend is slightly higher in Member States in which the species is listed as the SPA trigger.
Source: EEA, 2015b, Article 17 reports and assessments.
Figure 5.13 Conservation Status and trends for non-bird species listed in Annex II (left) and non-Annex II (right)
22%
5%
15%
12%
22%
24% 26%
3%
13%
26%
15%
17%
Non-Annex II species Annex II species
Unfavourable-improving
Unfavourable-unknown-trend Unknown
Unfavourable-stable Unfavourable-declining Favourable
Figure 5.14 Short-term population trends in Member States, where a species triggers SPA classification (left) and in Member States where it does not trigger SPA classification (right)
28%
33%
12%
27%
Species triggers SPA classification
21%
36%
18%
25%
Does not trigger SPA classification
Increasing Stable/fluctuating Unknown Decreasing Source: EEA, 2015a, Article 12 reports and assessments.