Approximately half of the total area of the Federal Republic of Germany is agricultural land. This means that agriculture has a major influence on both trends in biodiversity and the conservation of animal and plant species in the open countryside. Since the middle of the last century, increasingly intensive farming has led to a drastic decline in the area of land under diverse and extensive forms of agriculture and consequently in the associated biodiversity. High nature value farmland includes areas such as biodiverse mesotrophic grassland, non-intensively cultivated arable land, vineyards and fallow land. These tend to support not only a greater diversity of species, but also rare and specialised animal and plant species that have no chance of survival in intensively managed agricultural landscapes. Landscape features such as ditches, field shrubbery and dry stone walls, which give structure to the agricultural landscape and provide additional habitats for a wide range of species, all count as high nature value farmland. In the interests of biodiversity conservation and restoration in the agricultural landscape, it is essential that funding instruments be used to preserve and further develop areas of high nature value farmland. To make visible the successes and failures of the Länder, the Federal Government and the European Union in their efforts to improve the environmental situation in agriculture, a package of instruments is needed which can be used to identify areas of high nature value farmland and monitor their development over time.

For this reason, as part of the EU Common Agricultural Policy (CAP), the High Nature Value Farmland Indicator was added at the start of the 2007-2013 funding period as one of 35 agri-environmental indicators used to monitor the integration of environmental concerns into the CAP. The Federal Government and the Länder subsequently agreed to underpin this reportable indicator with a lean, sampling-based approach to facilitate standardised monitoring of HNV farmland in Germany.

At national level, the HNV Farmland indicator has since be added to the indicator set in the National Strategy on Biological Diversity and to the Plant Protection Index (PIX) in the National Action Plan on Sustainable Use of Plant Protection Products. At Länder level, it is part of the indicator set used in the Federal States Initiative on Core Indicators (Länderinitiative Kernindikatoren/LIKI).

Since 2009, the HNV Farmland indicator has shown the development of biodiversity in the agricultural landscape at federal and Länder level, both as an aggregate indicator and for individual types of vegetation, structure and land use.

HNV farmland monitoring is based on a set of representative sample plots across Germany, which are also used by the Federation of German Avifaunists (DDA) to monitor common breeding birds. The survey and extrapolation methodology was developed by the Federal Agency for Nature Conservation (BfN) in conjunction with the competent Länder authorities, the Federal Agency for Nature Conservation (BfN), the Federal Ministry of Food and Agriculture (BMEL), the Thünen Institute and the Julius Kühn Institute (JKI). HNV farmland monitoring involves regular surveys of approximately 1,700 sample plots throughout Germany over a period of four years. The various Länder each commission experienced surveying agencies with the surveying and recording of all HNV elements within the sample plots. These include all open countryside features in the agricultural landscape that have both high biodiversity and high structural diversity. This includes non-intensively farmed areas as well as landscape features and structural features. A standardised assessment is performed for each of the types listed above. If they meet the criteria for HNV farmland, they are recorded plot by plot and classified into three quality levels. Grassland, arable land, fallow land and vineyards are assessed according to the presence of specific plant species is used. These character taxa serve as indicators of a minimum level of diversity or non-intensive cultivation, and can be individual species, groups of species or all occurring species of a plant genus. Due to regional differences in grassland characteristics, different lists of character taxa are used for each region. The assessment is based on the number of character taxa found in a defined and standardised transect in each farmland plot. For the landscape and structural features, defined, type-specific criteria for species and structural diversity are used in the quality assessment. Where they are determined to be elements of the agricultural landscape, all Annex I habitat types of the Habitats Directive  and legally protected habitats are also considered as HNV farmland and are assessed as they would be in classifying the conservation status of Habitats Directive habitat types. 

The land use and habitat types in the agricultural landscape that are assessed in the course of HNV farmland monitoring are as follows:

Area type

• Grassland
• Orchards
•  Arable land
• Vineyards
• Fallow land
• Other open countryside habitats (legally protected habitats; habitat types)

Landscape features

• Rows of trees, groups of trees, solitary trees
• Hedges, thickets, copses, including woodland fringes
• Complex features, such as field margins and embankments with woody vegetation
• Natural stone and other dry stone walls, stone and rock ledges, sand, clay and loess walls
• Ruderal and herbaceous meadows and fringes, including tall grass stands
• Wetland features: sedge, reed and herbaceous plots in wetland sites/locations
• Surface standing waters up to 1 ha in size
• Ditches
• Streams and springs
• Unsurfaced farm roads and tracks/sunken lanes

In addition to providing purely quantitative results, classification into quality levels also enables information to be obtained on the qualitative status of HNV farmland elements as well as qualitative changes within the HNV sample plot network. All HNV types are classified into three quality levels: 

• HNV I    -    exceptionally high nature value
• HNV II   -    very high nature value
• HNV III  -    moderately high nature value

The first Germany-wide survey was conducted in 2009, jointly funded by the Federal Government and the Länder. Since then, about one quarter of the sample plots have been mapped in the various Länder each year, with some Länder also mapping half of the sample plots every two years. This means that all sample plots are fully mapped every four years. For the state of North Rhine-Westphalia, data that is likewise surveyed in a sample set for the Ökologische Flächenstichprobe (ÖFS) sample plot network is converted using a specially developed conversion tool into HNV farmland data for transfer to the national-level dataset. The city states of Berlin, Hamburg and Bremen do not participate in HNV farmland monitoring.

In addition to surveying high nature value farmland, the total area of agricultural land and changes in that total are recorded separately. This makes it additionally possible to track quantitative changes in the total area of agricultural land.

Extrapolation is carried out at both federal and Länder level, taking account of the stratification on which the sampling is based. Two stratification characteristics were used in sample selection: land cover (six classifications) and site classification according to ecoregions  (21 classes). The indicator values are extrapolated as moving averages. These are always based on the entire sample plot network in the year of sampling and the most recent mapping data. This approach allows annual reporting of the indicator at national level and either annual or biennial reporting at Länder level depending on the survey cycle used in each state.

To ensure consistently high quality of the data collected and also uniform assessment across the whole of Germany, BfN carries out rigorous quality assurance controls. These include annual training in mapping, a technical/expert assessment of all survey data and visual comparison of the data with recent aerial photographs. This ensures uniform conditions for mapping across Germany, minimises systematic deviations and reduces methodological variance. Quality management also includes various other measures such as a fixed number of annual control surveys to assess mapping quality. 

Since 2023, an online data entry tool has been available that simplifies the input of mapping results and plays an important role in ensuring data quality through a series of checks that take place during data entry.

Each step is accompanied by an annual meeting of a Federal-Länder specialist committee to discuss possible methodological problems and exchange experience and views. The meetings are coordinated by BfN.

The indicator values are expressed as the proportion of high nature value farmland in the total area of agricultural land. The total area of agricultural land is defined as the sum of farmed land and the structural features characteristic of farmed countryside. It provides the reference areas for use by the Federal Government and each of the Länder.

As of June 2023, data series are available from the complete survey in 2009 and from the subsequent surveys for the periods 2010 to 2013, 2014 to 2017, and 2018 to 2022. At national level, these show the following values extrapolated from the full sample (share of HNV farmland in the agricultural landscape as a percentage and absolute values in ha, with all values calculated using an improved methodology):

At national level, the overall value has decreased significantly over time, especially in the period 2009 and 2013. A gradual increase was observed from 2015 onwards. This can only be seen for the two higher quality levels, while the lowest quality level remains at a low level after a steep decline.

Looking at the individual HNV farmland types, it can be seen that the initial loss of HNV farmland areas is largely due to a decline in the quality or a reduction in the area of grassland, arable land and fallow land, while no significant change was observed in the case of landscape features. In the recovery from 2015, the increase in landscape features in particular more than makes up for the previous decrease. With the exception of grassland, farmed areas remain at the low level to which they had initially fallen. The initial increase in intensification has not yet been reversed on either arable or fallow land. In the case of grassland, divergent trends can be observed. While a positive trend can be seen for the higher-quality grassland in quality levels I and II over the nine-year period, grassland in quality level III, which in absolute terms accounts for the largest share of HNV grassland and all HNV types, remains at the low level reached after the initial steep decline.

It is important to note that the data illustrates the situation at national level. At Länder level, the trends present a very varied picture. Further information can be found on the LIKI website (see at the end of this section).

It is evident that the HNV Farmland indicator, using an efficient and effective approach, provides sound data on the quality and development of biodiversity in the agricultural landscape – data that can contribute significantly to the evaluation of EU agricultural policy and also measure the efficiency and effectiveness of agri-environmental measures and contractual nature conservation in Germany. 

The approach also has additional potential in that the data allow a more differentiated view of individual types as well as qualitative shifts within individual HNV types. This makes it possible to monitor quantitative developments and trends in HNV grassland, hedges, etc. and also qualitative changes within the individual HNV types in that their development is monitored separately in line with the different quality levels. These analysis options only reach their limits in cases where the rarer HNV farmland types are not recorded in sufficient numbers using the sampling process, thus reducing their statistical significance.

Over time, 11 of the 13 participating Länder have increased the number of sample plots, so that Germany now has around 1,700 sample plots in the monitoring programme. The Federal Government and the Länder benefit equally from this because it increases the evaluation options available to them, while lower sampling errors make it easier to identify trends at an early stage.  

HNV farmland data can also be correlated with other datasets and this is currently being tested in various research projects.

HNV farmland monitoring is thus a valuable source of data and has great potential for a wide range of research approaches and questions relating to biodiversity in the agricultural landscape.