Adaptation: Field of Action Biological Diversity

Adaptation measures in the area of biodiversity aim to increase the survival and functional capacity of organisms and to avoid or minimise undesirable effects of climate change on biodiversity. Adaptation measures cannot completely eliminate the risks of climate change, but they can increase the adaptive capacity of ecosystems and their species. The independent adaptation of ecosystems and species is particularly important for adaptation to climate change. According to current knowledge, the more intact the ecosystems and the higher their biodiversity, the more successful this adaptation will be, as it increases the resilience of the ecosystems. Humans can support the potential for independent adaptation (self-regulation) by ensuring the good condition and functionality of biodiversity and promoting diversity at all levels. Measures to maximise the potential for adaptation and strengthen the resilience of species populations in the face of climate change require a reduction of threats and a modification of existing conservation policies and strategies. Extensive biotope network to improve ecological connectivity and genetic diversity, habitat protection and restoration, and biodiversity conservation in productive landscapes are other strategies to maximise the adaptive potential of species.

At the species level, there are in principle several possibilities in which species and populations in an ecosystem can react to climate change and thus to a change in temperature patterns. They can either evade, adapt or become extinct. Adaptation therefore depends largely on the extent to which species are able either to colonise new climatically suitable habitats or to adapt to the new conditions through appropriate physiological or phenological changes without leaving their habitat. If evation or genetic adaptation is not possible and climatic conditions exceed the species' tolerance range, the species may become extinct in the affected area. Factors that can make it difficult for species to evade (migrate) to new habitats are the spatial fragmentation of suitable alternate habitats by roads and the lack of continuity of the intensively used agricultural landscape for dispersal and migration movements. In the mountains, animals can migrate to higher altitudes when it becomes too warm for them. However, the higher the animals migrate, the narrower the space they have available as well as the available food supply.

Another adaptation possibility is phenotypic plasticity, which is the phenomenon that occurs in many plants and animals whereby individuals with the same genotype (genetic information) develop different phenotypes depending on the prevailing environmental or climatic conditions. The phenotype refers not only to morphological, but also to physiological characteristics and, if applicable, to behavioral characteristics. Furthermore, adaptation in traits can be caused by genetic changes, i.e. ultimately by evolution. Evolutionary adaptation to climate change can only occur if there is heritable genetic variation in climate-relevant traits.

Indicators from the DAS monitoring: Protected areas | Consideration of climate change in landscape programmes and franework plans | Restoration of natural flood plains

Restoration of natural flood plains benefits floodwater protection and biodiversity conservation.

Source: Fernbach Antal / stock.adobe.com

Climate change and its consequences play increasingly important roles in landscape planning.

Source: ronstik / stock.adobe.com

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In addition to sometimes very specific species-related measures, measures to deal with invasive species should take three levels into account: 1) precaution, 2) monitoring, early detection, immediate measures, 3) acceptance, control and elimination.

Precaution: Since the spread of invasive species is usually unintentional and knowledge about the effects of invasive species is insufficient, education and awareness-raising are of great importance. The spread of invasive species can often be prevented if professional groups working in the open countryside, e. g. agriculture, forestry, horticulture, road construction and landscaping, use native species wherever possible. Private individuals should also be more aware of invasive species and refrain from introducing new species into nature and from disposing of garden waste in the open countryside. Preventive measures should be taken primarily in the area of (international) transport routes, as these represent a main pathway for the introduction and spread of invasive species. Concrete measures include: treating ships' ballast water with mechanical, physical or chemical methods before it is replaced, establishing ecological barriers in artificial water bodies such as shipping channels to prevent the unintended introduction of invasive species, or voluntary commitments to restrict the purchase or sale of potentially invasive exotic plants and animals. Furthermore, various legal regulations are available, e. g. a general ban on keeping, breeding, transporting, marketing and releasing under Regulation (EU) No 1143/2014 for species of the Union List and a ban on possession and marketing under the Federal Species Protection Regulations for certain invasive species. In addition, many countries have legally non-binding "lists of invasive species" that should not be released or should be removed if they occur.

Monitoring, early detection and immediate measures: The observation (monitoring) of the population development and spread of already introduced invasive species provides the basis for possible timely control or eradication measures. In order to detect newly emerging invasive species at an early stage, an early warning system must be established to assess whether introduced plant or animal species are spreading aggressively, becoming a threat to native species, and what measures can be taken to counter them. Regional web portals such as Neobiota-Nord are useful for this purpose. Should invasive species newly appear, the Federal Nature Conservation Act (§40a paragraph 1) stipulates that immediate measures must be taken to eliminate them or prevent their further spread. Early action in the case of newly emerging invasive species is intended to prevent possible subsequent extensive damage to the naturally occurring flora and fauna. Experience to date has shown that the longer one waits or the more widespread invasive species are, the more difficult and expensive it is to contain them.

Acceptance, control and removal: Most invasive species already present in Germany have integrated into our ecosystems and are therefore to be accepted as new plant and animal species. Many problematic neobiota species that are widely established will no longer be eradicable, so that they should only be combated in justified individual cases in order to keep them under control or to remove them locally. For this purpose, their effects should be known in the specific case and justify control. A distinction is made between different types of control measures. In physical control, the neobiota are, for example, regularly collected, removed from the soil or killed with firearms. Such methods often involve high costs and are ineffective when the population density of the neobiota is low. Chemical control involves the use of pesticides. The problem here is that the agents used often unintended harm native plant and animal species or humans. In biological control, natural enemies, parasites and viruses of the neobiota are introduced. Undesirable side effects can occur if the species introduced for control have a wide spectrum of effects, thereby reducing the population of native species. It is therefore important that species introduced for control have a high specificity of action. Another biological method is the sterile insect technique, in which mass-bred sterile males are released in a target area. Since the sterile males massively outnumber their free-living counterparts, most females mate with them - but do not have offspring afterwards. Genetically modified variants of the neobiota can also be introduced into the invasive population. By repeatedly releasing such individuals, harmful genetic material is introduced into the gene pool of the neobiota, which in the long run should lead to the extinction of the neobiota. There is a risk here that harmful genes will enter the gene pool of native species through hybridisation.

Adaptation to loss of genetic diversity: To mitigate and prevent climate change-induced loss of genetic diversity, a larger available gene pool of plant and animal species is generally beneficial. It provides them with the opportunity to adapt to changing climatic and environmental conditions. The conservation of native and wild animals and plants in permanently secured populations in their natural habitats is classified as essential for the preservation of genetic diversity. Ensuring the exchange between populations is a key factor in maintaining genetic variance, which requires habitats to be connected via a functioning biotope network. In order to promote connectivity between animal populations and thus genetic exchange, species can be relocated under certain conditions or barriers (e. g. highways) can be bypassed by building green bridges or creating stepping stone biotopes. The management of agricultural land according to the principles of organic farming is an important strategy from the perspective of biodiversity conservation. One conceivable measure here would be the preservation and expansion of extensively managed permanent grassland. In addition, the storage of plant seeds in gene banks contributes to the archiving of genetic diversity.

Adaptation to range shifts and population declines: To deal with range shifts and to avoid and mitigate population declines, survival opportunities for native species and habitats can be created through the development and implementation of a functional biotope network, thus enabling organisms to adapt to climatic changes. Existing habitats of endangered and/or climate-sensitive species must be optimised to make them more resilient and adaptable, e. g. by providing sufficiently large areas with a biotope protection function, intensifying development measures to promote greater closeness to nature of ecosystems, and allowing natural succession of ecosystems. In principle, there is a need for increased implementation of national programmes such as the National Strategy on Biological Diversity, the nature conservation support programmes, the programmes for reconnection and the biotope network to strengthen traversability and habitat connectivity, as well as nationwide, regional and local support programmes.

Adaptation to damage to water-bound habitats and wetlands: Adaptation of water-bound habitats with a particular sensitivity to climatic changes (e. g. bogs, salt marshes, small streams, floodplains, springs) can start with the conservation or restoration of these habitats. This includes renaturation measures on running waters and floodplains (e. g. land-use change, dyke relocation, shoreline restoration, connection of oxbow lakes, ecological continuity, achievement of good ecological status, creation of biotope networks) and measures to secure the existence and rewetting of raised bogs and fens (e. g. maintenance and restoration of natural water levels, compensation payments to farmers, purchase of agricultural land, research on sustainable bog use).

Adaptation to damage to forests: A key objective of measures to adapt to the climate impact "damage to forests" is to create and permanently secure site-appropriate, near-natural, structurally rich, climate-stable and ecologically high-quality forest ecosystems with predominantly native tree species. Measures include the establishment of near-natural mixed forests, the promotion of natural regeneration of forests over planting on suitable sites, the orientation of the level wildlife populations and hunting to the needs of forests, the dissemination of information on the extent and effects of climate change on forest ecosystems, and the intensification of research on the interactions of climate change, pests and abiotic and biotic damaging factors and their influences on our forests.