El pequeño libro que aún no tenía nombre / José Antonio Millán; Perico Pastor

Being aware of prospective impacts of the changing climate to the ecosystems and habitats of the Biebrza Valley defined on the basis of given climate change scenarios, the next step in the analysis was to assess the sensitivities, exposures and potential impacts of climate change to habitats of the Biebrza Valley. As the CAMP refers to the whole area of the BNP, certain assumptions had to be made and the spatial extent of particular types of habitats had to be generalised (Fig. 2).

Habitat sensitivity in this approach was considered a result of its characteristics and existing or future pressures. The characteristics of habitats are the results of the effective abiotic factors like climate conditions, topography, soil type or disturbance regimes and biotic factors like species distributions, competition or regeneration rates. These characteristics describe the ecological envelope of the habitats. However, existing non-climatic pressures like land use changes modify the resilience of habitats to climate change on the local level (Wagner et al. 2012).

Spatial clusters of habitats were assessed as to their sensitivity to potential impacts of climate change. For each habitat type each criteria was evaluated from the experts between the values “low” (1), “medium” (2), and “high” (3) as to their sensitivity. Afterwards, these values were summed and categorised to describe the overall sensitivity of a habitat type. Thereby, the categories were named similar to the evaluation values. This evaluation was done from regional experts for the Alpine, Continental and Pannonian biogeographical region. The framework for the regional expert knowledge was based on the approach developed during the sensitivity assessment of Natura 2000 habitats in Germany by Petermann et al. (2007). The assessment was structured into seven sensitivity criteria:

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Figure 46. Selected habitat sensitivities to particular potential climate change impacts according to the Petermann scale.

(Source: Wagner et al. 2012; modified).

1. Average or reduced conservation status: habitats which are already marked as endangered are more sensitive;

2. Ability to regenerate: how long habitats need to recover after disturbance;

3. Horizontal distribution (range): species migrations due to climate change (e.g. from Northwest to East)

4. Altitudinal distribution (range): species are forced to migrate upwards

5. Decrease of territorial coverage: remnants of habitats which are already endangered 6. Influence of neophytes (invasive species) that follow the changing climatic conditions 7. Dependency on groundwater and surface water in water balance

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The majority of the habitats of Biebrza National Park was assessed as of the medium and high sensitivity (Fig. 46 A). The highest level of habitat sensitivity was defined for potential changes in water levels and soil moisture content (Fig. 46 B) and relatively low sensitivity of habitats was defined in reference to potential decrease of spatial extents of habitats in result of a changing climate (Fig. 46 D). It is also suspected, that majority of the habitats of BNP are capable for the self regeneration in projected conditions of climate change (Fig. 46 C), which is a good prerequisite for the habitat restoration measures. It is also suspected, that the majority of the habitats of Biebrza National Park is moderately sensitive to potential occurrence of the invasive species. For detailed interpretation of the habitat sensitivity assessment, the reader is referred to Wagner et al. 2012.

Figure 47. General assessment of Biebrza Valley wetland habitats’ exposure to potential climate change impacts in different vegetation seasons (VEG1/3 – beginning of the growing season, VEG2/3 – peak of the growing season, VEG 3/3 – end of the growing season, DORM – dormant season)

(Source: Wagner et al. 2012).

The analysis of habitats exposure to particular influences of climate change was done in reference to particular parts of the growing and dormant season. The growing season was divided into 3 parts (1/3, 2/3 and 3/3) and the dormant vegetation season was separately considered in the analysis (Fig. 47).

Among the analysed exposures of the possible climate change impacts, the change of the average seasonal air temperature, minimum and maximum seasonal air temperature, climatic water balance (modelled P-ET) as well as changes in precipitation and the number of dry days were considered (Fig. 47). The overall habitat exposure to projected climate change impacts was assessed for each of the analysed growing and dormant seasons (Fig. 48-51).

Figure 48. Qualitative assessment of potential impacts of climate change to habitats in the Biebrza Valley in the first part of the growing season (VEG1/3).

(Source: Wagner et al. 2012).

In the general scale of generalised habitats of the Biebrza National Park, the highest summary impact of projected climatic change was defined for the first months of the growing season (mid March-mid May; Fig. 48). The projected impacts of changing climate to the analysed habitats was defined as decreasing in the following seasons (Fig. 49-50) to reach the minimum impact in the dormant season (Fig. 51).

Considering presented results it can be concluded, that among the temporal and spatial patterns of the potential climate change to be referred to in the management adaptation, the physical processes responsible for impacts in the first part of the growing season are of the highest importance. Hence, in the first steps of management adaptation, the habitat conditions in the beginning of the growing season should be monitored, and according to the results of the monitoring, management measures should selectively be applied. This aspects are further developed in the chapter 10 of the presented CAMP.

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Figure 49. Qualitative assessment of potential impacts of climate change to habitats in the Biebrza Valley in the middle part of the growing season (VEG2/3).

(Source: Wagner et al. 2012).

Figure 50. Qualitative assessment of potential impacts of climate change to habitats in the Biebrza Valley in the end of the growing season (VEG3/3).

Figure 51. Qualitative assessment of potential impacts of climate change to habitats in the Biebrza Valley in the dormant season (DORM).

(Source: Wagner et al. 2012).