Cluster Biological diversity

Biological diversity is one of the fundamental requirements for the life of human beings. Animals, plants, fungi and micro-organisms contribute to providing clean water, fresh air, a pleasant climate and fertile soils for the cultivation of crops to produce healthy food. Another useful function of stable ecosystems is that they capture carbons from the atmosphere, binding and storing them long-term, thus contributing to the provision of natural climate protection as long as these ecosystems remain in a stable condition. However, biological diversity is endangered. Next to changes in land use, climate change is one of the major factors of influence on biological diversity. This is because its influence is spread across all levels – from single individuals to communities of species and ultimately to complete ecosystems.

Increased warming leads to phenological shifts in the seasons. The development stages of plants set in earlier in spring, summer and autumn. In contrast, winters are increasingly becoming shorter and milder. The vegetation period is lasting longer overall (cf. Indicator BD-I-1). Abiotic stress due to heat and drought causes major ecological damage: Habitats adapted to cooler conditions are shifting in the direction of the poles (cf. Indicator FI-I-1) and in the direction of high altitudes in the mountains. In particular, habitats which provide specific conditions for animals and plants adapted to such conditions are either shrinking or lost entirely, while widespread species but also non-resident species expand their ranges.

Species diversity is at risk in places where reproduction or food sources no longer occur synchronously in space or time and complex interactions among species communities are disturbed (cf. Indicator FI-I-2). For example when the supply and demand of food are decoupled from breeding and hatching times, this will also affect the functionality, the existence and the resilience of entire ecosystems. The decoupling of interspecies relationships such as competition, prey-predator relationships, host-parasite relationships or symbioses – which can also exist between animal and plant species – can have far-reaching economic and social consequences which must be responded too. This also applies to important processes in agriculture such as pollination or the natural control of pests (cf. Indicators LW-I-4).

Climate change entails changes in species communities. This is demonstrated, for instance, by relationships between birds and butterflies (cf. Indicators BD-I-2 and BD-I-3): Thermophilic species are on the increase whereas cold-adapted species are in decline. Moreover, the expansion of invasive species (cf. Indicator GE-I-4) can become a hazard for native biodiversity.

In general it can be said that it is very difficult to identify or even quantify the direct impacts of changing climatic conditions on the development of biological diversity. The interaction of various factors of influence on ecosystems and the communities involved in ecosystems is highly complex. However, in the estimation of specialists, climate change has a much more indirect impact on biological diversity where changes in land use are involved: Climate protection and adaptation measures can result in changes to land use which can have both positive and negative consequences for biodiversity. Such measures can involve the installation of renewable energy systems, the production of biomass, the increased implementation of agro-forestry measures, or the restoration of natural flood plains for protection from floodwater, as well as the renaturation of moorlands in order to strengthen their function as CO₂ sinks.

Already now, a third of the species occurring in Germany are endangered in terms of their populations. Apart from increasing demands on land use by humans, climate change represents a major stress factor owing to changes in temperature and precipitation and the increase in extreme weather events such as prolonged periods of drought or heavy rain. As mentioned in the outcomes section of the 2021 Climate Impact and Risk Analysis (KWRA) it is conceivable that major risks regarding changes in vegetation periods and phenology as well as in the spread of invasive species might arise by the middle of this century. Ecosystems in mountain ranges, aquatic habitats, wetlands and woodlands are estimated to be particularly endangered. In addition, high risks are expected to ensue by the end of this century from losses in genetic diversity, the shift of territories, a decline in populations and the loss of ecosystem services including high risks in coastal ecosystems. In other words, all climate impacts evaluated in KWRA 2021 and covered by the action field ‘Biological Diversity’ entail high risks emerging by the end of this century.

There are knowledge gaps and uncertainties to what extent direct and indirect impacts of climate change will affect biological diversity and how best to counteract such impacts. These gaps and uncertainties are due to the fact that there are numerous other factors to be considered in addition to climate change. There is, in particular, a lack of data on cause-and-effect relationships among changing climatic phenomena (such as increasing summer drought) and the biological response of species, species communities and ecosystems as well as a lack of data on adaptation and expansion options available to any animal and plant species concerned.

The newly founded National Monitoring Centre for Biodiversity (NMZB) in Leipzig has been working since 2021 on establishing a knowledge base by collecting data on the state of species and habitats in Germany and to develop an overall concept for biodiversity monitoring nationwide.

In order to improve the protection of biodiversity under changing climatic conditions, it is essential to maintain sufficiently large populations and their genetic diversity, as well as ensuring that their habitats are available in sufficient quantity and quality and that these habitats are networked well.

The ‘Kunming-Montreal Global Biodiversity Framework’ (GBF) adopted in December 2022 has set global objectives for the protection and maintenance of biological diversity. One of the objectives is to improve or restore the connectivity and resilience of ecosystems worldwide and to expand the terrain of natural ecosystems substantially. It is up to the 196 signatories to the Convention on Biological Diversity (CBD) to put their resolutions into practice. The EU Biodiversity Strategy for 2030 for the conservation and restoration of wildlife was adopted in 2020 at a Europe-wide level.¹²⁴

The Federal government’s core nature conservation strategy is the National Biodiversity Strategy 2007 (NBS). Work is currently ongoing on Germany’s NBS 2030. The aim is that issues such as impacts of climate change, adaptation to climate change and climate protection be addressed more forcefully than before. At Länder level, 15 of Germany’s 16 Federal States have biodiversity or nature conservation strategies in place – in some cases in the form of action plans which, as at Federal government level, typically address the relationship between climate change and biodiversity. Likewise, there are other relevant national strategies in place: The National Water Strategy¹²⁵ (2023) addresses the protection of groundwater, streams, rivers and lakes, as well as the permanent safeguarding of a near-natural water budget. The Federal programme ‘Blaues Band’ (Blue Belt, 2017) supports renaturation measures in alluvial meadows of Federal waterways; its intention is to create a biotope network. The funding programme ‘Förderprogramm Auen’ enables municipalities, associations and organisations to apply for funding to further the near-natural development of biotope networks in alluvial meadows. At the same time, the expansion of natural flood plains also benefits the protection from floodwater and the protection from flooding in the event of flash floods¹²⁶. The restoration of natural flood plains by means of dyke realignment enables the reconnection of flood plains with rivers. At the same time, this is also a measure of natural climate protection. In 2020 the terrain of restored natural flood plains amounted to a total of 7,100 ha. Compared to 2019 this represents a gain amounting to 716 ha added to the previous total (cf. Indicators BD-R-2).

Germany’s National Peatland Protection Strategy (Moorschutzstrategie / 2022) created the political framework for all aspects of peatland protection for years to come. A very low percentage of German peatland is still in a near-natural condition. Consequently, the species diversity typical of peatlands is severely endangered. The aim therefore is to protect near-natural peatlands rigorously, to strengthen their CO₂ sink function, and to improve their hydrological condition in such a way that they fulfil their potential as habitat for species adapted to wetlands as well as for water retention in the landscape, thus contributing cooling effects and meeting the objectives of adapting to the impacts of climate change.

Climate change is also getting more consideration in landscape programmes and landscape framework plans these days (cf. Indicators BD-R-1). More than two thirds of the Länder’s landscape programmes and 50 % of regional landscape framework plans have incorporated the climate change theme in connection with issues of nature conservation.

Nature reserves and national parks are particularly well protected areas which make them important refuges with, on principle, favourable conditions for the conservation of those species and habitats that are at particular risk from climate change. By 2020, the proportion of strictly protected areas in Germany increased to a total of just under 4.6 % (cf. Indicator BD-R-3).

Already since 2004 the Federal Agency for Nature Conservation (BfN) has been organising the conference entitled ‘Biodiversity and Climate – Networking the Stakeholders in Germany’ with the aim of promoting the exchange of research outcomes among specialists in the overlapping fields of biodiversity, nature conservation and climate change. Specialists use this annual event to discuss in what way measures for the maintenance of biological diversity might also be used in supporting measures for adaptation to climate change and how to shape adaptation measures in ways to obtain synergies with nature conservation.

On 29th March 2023 the federal government adopted the action programme ‘Natural Climate Protection’ (ANK). Woodlands and alluvial meadows, soils and peatlands, seas and water bodies, near-natural green spaces in urban and rural areas all contribute to capturing CO₂ from the atmosphere and to provide long-term storage. Furthermore, these areas can buffer negative effects of climate change by retaining water in the landscape, by capping floodwater peaks and by providing air for cooling purposes. At the same time, they safeguard important habitats for animals and plants. In towns and settlements, nature provides better air and shade and acts as a cooling agent on hot summer days. Contiguously linked near-natural green spaces form cold air and fresh air channels and provide habitats and refuges for many animal species. Á multitude of measures is intended to ensure that degraded ecosystems are restored to good health, resilience and diversity. The programme is financed largely from the new climate and transformation fund. Up to 2026 there is a total of four billion Euros available. The focus is on the funding of tangible renaturation measures and incentives for climate-friendly and nature-compatible forms of management.

^{124 - Europäische Kommission: Biodiversity strategy for 2030.
https://environment.ec.europa.eu/strategy/biodiversity-strategy-2030_en.}

^{125 - BMUV – Bundesministerium für Umwelt, Naturschutz, nukleare Sicherheit und Verbraucherschutz: Nationale Wasserstrategie. https://www.bmuv.de/wasserstrategie.}

^{126 - BfN – Bundesamt für Naturschutz 2023: Handlungsempfehlungen zum Schutz vor Hochwasser und Sturzfluten. https://www.bfn.de/pressemitteilungen/handlungsempfehlungen-zum-schutz-vor-hochwasser-und-sturzfluten.}