Those wishing to promote biodiversity in agriculture by means of result-based schemes need meaningful indicators. An overview of proposed and used indicators highlights developments and challenges.
Agri-environmental schemes in which farmers can take part and in exchange receive direct payments are a key element of agricultural policy for promoting biodiversity. These schemes fall into two categories: action-based and result-based agri-environmental schemes.
With action-based schemes, farmers are paid for implementing specific measures (e.g., reduced fertiliser application and fewer cuts in grassland). With result-based schemes, by contrast, they receive support for achieving certain results. The latter types of schemes offer various advantages, for example, fewer regulations and greater flexibility for farmers. However, the success of result-based schemes depends decisively on the indicators used to measure biodiversity.
Indicators proposed in the scientific literature versus those used in practice
The aim of our study was to better understand how and when biodiversity indicators can be used for result-based agri-environmental schemes. For this, we have (a) created a systematic overview of the biodiversity indicators proposed in scientific studies and used in practice in Europe, and (b) based on this, outlined the future prospects for these result-based agri-environmental schemes based on biodiversity indicators.
Most common: plant species as indicators of biodiversity in grassland
Our analysis of the proposed biodiversity indicators shows that most agri-environmental schemes proposed in scientific studies use vascular plants as indicators for representing plant diversity in grassland (Fig. 1). These indicators (consolidated into indicator lists) are usually developed uniformly for large regions, such as (German) federal states or entire countries. In more-recent scientific studies, however, it is more common for indicator lists and sets consisting of various indicator lists to be proposed that take more aspects of biodiversity into account (for example, endangered plant species and extensive-grassland plant species, or various taxa), are adapted to smaller scales, and consider other agroecosystems besides grassland.
For the schemes existing at present in practice, we observe similar patterns: older schemes mainly use grassland plant species as indicators. Moreover, they are often not adapted to smaller regional scales. Systems introduced more recently are based on broader indicators and also take smaller scales into account.
Switzerland has a relatively large number of result-based schemes (also known in Switzerland as QIIs, e.g., for promoting biodiversity in grassland and in land under vines. In addition, payments to farmers in these schemes have been increased in recent years. At EU level, various Member States are planning new result-based schemes under the EU Common Agricultural Policy reform (2023–2027). Ireland, for example, aims to rely on different indicator sets for high- and low-intensity management grassland in order to identify biodiversity.
New technologies facilitate biodiversity measurement
Various technological advances could potentially facilitate the use of biodiversity indicators and save both costs and time. Examples of technologies of this sort are simulation models, digital solutions (e.g., smartphone apps, drones and satellites) and genetic markers (eDNA barcoding). Most of these technologies are not yet usable, however – for example, smartphone apps are already available for identifying plant species, but these are not yet geared to measuring indicators, or are not yet used for this purpose.
- Existing indicators – both those proposed by in the scientific literature and those used in practice – are usually based on lists of grassland vascular plants. Indicators for other agroecosystems are often lacking.
- The choice of biodiversity indicators and the design of result-based agri-environmental schemes should be based on biodiversity promotion objectives. Moreover, the relative benefits and costs of biodiversity promotion must be weighed up.
- The choice of indicator lists enables policy decision-makers to take account of and promote various aspects of biodiversity in a cost-efficient manner.
- In future, new technologies will also potentially be able to contribute to improving how biodiversity indicators are designed and compiled.