Fig. 5.16 Shifting ecological zones in the US (Source: Committee on Ecological Impacts of Climate Change, 2008)
ecological policy to a dynamic strategy, which focuses on the resilience of ecosystems and the capability of species to recover (Vos et al., 2007a). In this strategy resilience and recovery need to be translated into spatial dimensions. The ecological main structure and its surroundings need to be adjusted according these principles and the objectives need to be changed: from rarity of species to an approach based on the functioning of the ecological system. Then, a stronger and more integrated role of nature in spatial planning can be reached. Several spatial strategies are described
1. Improve the spatial coherence between the ecological main structure and Natura 2000 areas (nature reserves, which received a protected status at a European level, Bird directive and/or Habitat directive). The objective is to preserve species, for which climate becomes less suitable, in the best available areas and to provide areas where species, for which climate becomes increasingly suitable, can move to. Species are only capable of follow the shift of their habitats if new areas are within their dispersion range and if areas are large enough to support species in dealing with weather extremes. The spatial coherence of areas is very important to prevent species from regional extinction, which happens easier if areas are split up. The Natura 2000 areas do not form a connected network yet and this causes a difficult adaptation to climate change for many species. They are hindered to move and therefore they cannot follow the most optimal climatic circumstances (Change magazine, 2006a). The ecological main structure and robust ecological connections, which are additions to the ecological main structure in order to enlarge the spatial coherence between regions and offer less mobile species the chance to move (LNV, 2001), need to be connected with international ecological zones, areas need to be enlarged and small areas need to be connected with each other;
2. Spatial measures at area level in order to increase the resilience of ecosystems. The objective is to sustain biodiversity at current level. Ecosystems are better equipped to deal with changes in species interactions and increasing disturbing events. Enlargement of nature areas and internal heterogeneousity offers space to species and improves the ability to recover;
3. Adjust abiotical conditions in nature reserves. The objective is to offer more space to natural processes in nature reserves and to solve changes in water and nutrients availability. If climate change causes changes in the existence of nutrients, ecosystems become eutrophic and become rougher: biodiversity decreases. Climate change affects the availability of water also: droughts as well as inundation in case of extreme rainfall. Space needs to be created to provide area for increasing dynamic in water patterns;
4. Creation of a multifunctional climate mantle (Fig. 5.17) around the ecological main structure. The objective is to develop functional connections between the ecological main structure and the surroundings. The resilience and recovery capacity of the landscape is improved. The climate mantle provides the space to relief pressure from recreation or environmental hazards on the ecological structures. Finally the mantle offers flexibility to deal with unexpected climate change. The climate mantle is a zone around the ecological main structure, consisting of cultural landscape and capable of increasing the climate proofing of the ecological main structure. In the mantle nature is mixed with water functions, agriculture and recreation. The green-blue veined landscape offers risk reduction for the effects of climate change, like floods or plagues and is capable to store water;
5. Nature as an integrated part of multifunctional spatial developments. Te objective is to integrate nature in spatial decision-making at all levels of scale. Nature is able to serve as relief bringing function in times climate change affects all other spatial functions, like living and working. This may lead to a flexible coastal defence using natural processes, control of water dynamic in catchment areas using nature as a sponge or nature in the city as bearer of the quality of life and the power nature has to fixate CO2 and thus contributing to mitigation of climate change;
6. Increase the learning capacity and dealing with uncertainties;
7. A new vision on nature in spatial planning.
The National Environmental Assessment Agency formulated slightly different strategies (Groot et al., 2006):
a. Design and Implementation of ecological networks (green corridors and ecological zones). Considering the expected speed of future climate changes, there will be little time to adapt to new conditions within the present home range, both behaviourally and/or evolutionary. Without special measures, extinctions of local populations are very likely to increase. Often due to the isolation of most nature areas, migration and adjustment of distribution ranges will be difficult for most species. The establishment of green corridors and ecological zones are very important to support adaptation of species especially those with low migration capabilities (Groot and Ketner, 1991). Ecological networks are a set of ecosystems, linked through robust corridors, providing space for species and allowing them to easily shift their habitat. The Ecological Main Structure has been designed with the main purpose of restoring natural ecosystems lost during the past years as a consequence of human actions. Although the Main Structure was not originally meant as a climate adaptation measure, the creation of the Structure can enhance the adaptation capacity of species to climate change. The current design of the ecological network should therefore be reconsidered to take better account of the pressures imposed by climatic change. It is very important to improve existing corridors between green areas, and establish new ones, to allow plants and animals, especially those with low migration capabilities, to follow favourable environmental circumstances. New corridors can be created through rehabilitation of degraded areas or conversion of areas, which were used for other purposes (e.g. agriculture);
b. Protected Areas should be screened on their suitability under changing climatic conditions. In general, climate change will lead to more instability in nature, which requires more 'adaptive management' and more space for species to allow them to adjust their distribution and/or phenology to changing environmental conditions. The selection of sites should focus on areas, which have the highest potential to provide suitable habitats to threatened species under changing climatic conditions. In Europe, this will usually be to the north of the current distribution limit of the species (Groot and Ketner, 1991). In order to increase the robustness of ecosystems, it is also necessary to adjust management strategies for protected areas, e.g. to ensure certain environmental conditions, take into account pest-control measures or adjust water management. New protected areas can be developed through acquisition of land and change in land use;
c. Adjustment of mix of tree species. The dispersal rates of trees is very slow compared to the expected speed of climatic changes and corridors may not be able to counteract the negative effects on some tree species, calling for active afforestation measures. Afforestation can contribute to create new green areas and increase the robustness of existing forest ecosystems. New forest areas will also counteract the loss of forest caused by excessive drought in summer. When planting a forest, particular attention should be given to the selection of species. Adjustment of forest management can occur in already existing forests for the main purpose of decreasing the vulnerability of the ecosystem. For example a switch from single-stand to mixed forests, a switch from drought sensitive species to more resistant species and the use of a more broad range of species will help to spread the risk of possible negative effects.
d. Artificial translocation of plants and animals is proposed as a way of preserving species under climate change. They also emphasize the importance of using various management approaches according to specie's climatic tolerances and dispersal abilities. For example, for the conservation of many mammals, artificial translocation may be more useful than the creation of large-scale migration corridors; whereas wind-dispersed plants may be best conserved in disjunctive reserves aligned in the direction of projected climate change.
e. Although not meant as an adaptation strategy to climate change, agri-environmental schemes could contribute in maintaining a variety of valuable semi-natural habitats, maintaining or increasing species richness and thus enhancing the resilience of the natural system against climate change. These measures, however, are not always effective in conserving and promoting biodiversity. A more accurate design of the measures is needed in order to obtain positive impacts on biodiversity. Kleijn and Sutherland (2003) suggests that in some cases agri-environmental schemes that aim to protect biodiversity in extensively farmed areas can be more effective than those aiming to improve biodiversity in intensively farmed areas; in some cases the success of the scheme may depend on the motivation of the farmers and on the amount of support, feedback, encouragement and supervision that they receive.
f. Integrated water management for ecosystems. The Dutch water policy recognizes the necessity of dealing with changes in water levels. Sea level is expected to rise as well as peak discharges of the rivers. Moreover, there is the necessity of storing water from heavy rains and counteracting drought, both likely consequences of climate change. Next to safety issues, conservation of the ecosystems is considered an important goal. After the major floods of 1993 and 1995, traditional ways of managing water (i.e. building higher dikes) are not considered the best options. The notion of fighting against possible events like flooding is been replaced with the notion of adapting to changes. Instead of thinking of creating new heavy infrastructures, which have severe consequences for the environment, a new vision started to develop. Creating more space for water, besides increasing the water storage capacity and benefiting landscape, can offer space to plant and animal species. Appropriate water management can allow adequate storage of water from heavy rains and can help in counteracting drought, both likely consequences of climate change. However, it should be realised that existing natural habitats are likely to disappear when faced with increasing incidence and/or magnitude of inundations.
g. Integrated Coastal management. Sea level rise and flooding are main threats in the coastal areas, especially in low-lying areas. The following adaptation strategies can be considered:
• Re-establishment of the natural dynamics of the dunes. This can create opportunities for nature development and can reduce the risk of flooding, thus can prevent damages to the ecosystems;
• Use of natural areas (e.g. peat lands). These natural areas, besides enhancing the natural functions of the coastline, can increase the water retention capacity of the coastal zone, reduce the risk of salt water intrusion caused by sea level rise (Ierland et al., 2001) and prevent damage to the natural system.
• An expert group (CPSL, 2005) investigated some solutions for coastal protection and sea level rise in the Wadden Sea. Some of the measures combine the social and economic requests with the ecological function. They can protect valuable habitats and biodiversity enhancing resilience against climate change. Some measures considered are:
• Enhancement and maintenance of salt marshes. Salt marshes have a high ecological value since they constitute the habitat for several types of birds, for halophytic plant species and partly highly specialized invertebrate fauna (e.g. arthropod species).
• Development of mussel beds and sea grass fields. Besides helping to safeguard, on a local scale, inter tidal areas from drowning, this measure can provide favourable conditions for other species and is therefore enhancing biodiversity.
8. Restoration of ecosystems directly depending on water quantity or quality. In autumn 2000 the EU Water Framework Directive (WFD) was published. The WFD does explicitly state that: '[it] contributes to mitigating the effects of floods and droughts'. Moreover, it also aims at 'preventing further deterioration and protecting and enhancing the status of aquatic ecosystems and, with regard to their water needs, terrestrial ecosystems and wetlands directly depending on the aquatic ecosystems'. Thus the WFD may be considered to be one of the means to enhance resilience of nature against any change, including impacts of climate change.
In order to increase functional connectivity, which aims to reduce further fragmentation across ecological networks in Europe, the following framework is proposed to implement the Birds and Habitat Directive (Kettunen et al., 2007):
a. Identify species and habitats of Community interest that are already impacted by or vulnerable to fragmentation and/or changes in climate space (using a proposed risk assessment framework);
b. Assess the functional connectivity requirements of vulnerable species and habitats, taking into account likely habitat fragmentation and climate change impacts where necessary;
c. Integrate functional connectivity requirements into ecological networks and generic habitat measures across the wider environment;
d. Implement connectivity measures through existing mechanisms, such as protected area management processes, planning regulations and policies, land-use policies and EU funding mechanisms.
It may be concluded that several adaptation strategies can be used to increase the adaptive capacity of the ecological system and create the possibility for species and ecosystems to move with shifting climate zones. In general the proposed adaptation strategies can be divided into two types of measures: measures to improve the quality and management within existing ecological areas and measures that are aiming to expand and connect ecological areas.
If the different adaptation strategies are summarised the following connections become visible:
The aim is to develop coherent ecological networks en corridors, which connect the fragmented protected areas within the Ecological Main Structure with those of Natura 2000. The abiotic conditions need to be improved, which are able to increase resilience of the areas and are able to restore ecosystems, depending on water quality and quantity, forests, coasts and as part of agricultural schemes. A clear vision on nature as part of spatial planning enables to formulate the areas where the ecological system need to expand, as a climate mantle, as part of a multifunctional zone or as space where artificial translocation may take place. Constant alertness on an ongoing adaptation to changing circumstances stays necessary. Therefore, increase of the learning capacity needs to be improved constantly.
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