The inclusion of a site in the ZNIEFF inventory is based on the presence of a species or associations of species of high ecological value (named ‘determinant species’ in the ZNIEFF terminology). The presence of at least one determinant species makes it possible to create a ZNIEFF. The data on remarkable species and habitats in the area are collected, analysed and synthesised (Horellou et al. 2017). There are two types of ZNIEFF. Type I ZNIEFFs are ecologically-homogeneous areas, defined by the presence of species, associations of species or habitats that are rare, remarkable or characteristic of the regional natural heritage. Type II ZNIEFFs usually correspond to larger areas that integrate functional and landscaped natural zones. Type I ZNIEFFs can be included in type II ZNIEFFs (Horellou et al. 2014). If all the determinant species become extinct in an area, the site loses its official designation as a ZNIEFF.

The Regional Scientific Council for Natural Heritage (CSRPN) scientifically validates the naturalist surveys (sites and species) in each administrative region in close relationship with the regional services of the Ministry of Ecology and their scientific secretariat ‘ZNIEFF’, while the French National Museum of Natural History is in charge of the national consistency.

A ZNIEFF is not a ‘protected area’ per se, but rather a survey of naturalistic knowledge on specific sites known to shelter remarkable species and/or characterised by remarkable environmental features (e.g. a moor on serpentine). The ZNIEFF inventory is central for prioritising issues of natural heritage, defining the national biodiversity strategy and its regional sub-strategies, creating protected areas and for generating new knowledge. It has been one of the most important items when defining the French National Strategy for the Creation of Protected Areas (SCAP). In 1993, the ZNIEFF inventory facilitated the implementation of the European Habitats Directive concerning the conservation of natural and semi-natural habitats, as well as wild fauna and flora, enabling the constitution of an operational Natura 2000 network of sites. Finally, it constitutes a decision-making tool and is frequently used for environmental studies related to land planning. Generally speaking, the ZNIEFF inventory has been one of the main factors in collecting and gathering naturalist's knowledge on the national level for almost 40 years.

The notion of ‘determinance’ is the cornerstone of the ZNIEFF inventory and literally means ‘which determines the value and justifies the choice of the geographic area’. Each ZNIEFF must necessarily contain at least one ‘determinant’ species (also called ‘trigger’ species in scientific literature) to be considered as such. The determining characteristic is the intrinsic value of the species (e.g. localised, threatened on the regional, national or international level, endemic, at the limit of the range etc.), combined with the particular conditions of the site (notably, the importance of the species population in the region with respect to its presence in other regions and its global geographic distribution). In addition to these determinant species, the ZNIEFF inventory also takes into account determinant habitats, which contribute to the selection of the area on their own value or that of the species they shelter. Data related to other (non-determinant) species are also collected during field surveys and generally included in the dataset, given that it is useful for understanding the global ecological functioning of the ZNIEFF or to anticipate global anthropogenic threats or more local impacts (e.g. extension of the range of species due to climate change or urbanisation). Only data concerning species (not habitats) will be presented in this datapaper, as habitat data do not yet benefit from viewing and downloading tools at the national level.

There is a particular case of species with ‘confidential distribution’. This concerns a limited number of species in a given region that are particularly ‘sensitive’, i.e. subject to harmful human activity and for which the availability of data is likely to increase the likelihood of the harmful activity occurring (Chapman and Grafton 2008). This may concern species which are threatened, rare and/or of high heritage interest and for which the dissemination of information represents (in the regional context) a risk of targeted destruction. This dissemination of information could also seriously affect the conservation status of the population of a species or the habitat that shelters it. The confidentiality of a species must, however, remain exceptional and is assessed on a case-by-case basis on the regional level by the scientific council. The corresponding data are excluded from the dataset on the INPN website and the GBIF portal.

In addition to this notion of confidential data specific to the ZNIEFF programme, there is also a national programme on 'sensitive data'. This programme is recent and aims to harmonise and implement blurring of what is called sensitive/confidential/restricted data in some French datasets, including the ZNIEFF inventory. Data considered sensitive can be blurred more widely than a zone, i.e. to the Municipality, the Department, a grid cell etc. This is mentioned in the 'informationWithheld' and 'dataGeneralizations' fields of the ZNIEFF dataset.

The data span the years 1757 to 2019.

The ZNIEFF inventory was officially launched in 1982, but data prior to this date have been taken into account to justify the ecological value of some areas. There were two inventory phases (i.e. ‘generations’ according to the ZNIEFF terminology). The first generation took place between 1982 and 1995, while the second generation lasted from 1995 to 2014 (Horellou et al. 2017). These phases corresponded to important methodological changes. Since 2017, the ZNIEFF inventory is continuously updated, that is to say, there are now no more ‘generations’.

The effort put into field surveys and data collection in regional information systems was very important until 2010 (Fig. 6). Following this tremendous collection effort, the subsequent sampling effort on the regional level became more qualitative, mainly dedicated to determinant species and taking into account the territorial specificities in terms of natural habitats and naturalistic networks. Despite the drop in annual record count observed in Fig. 6, new data are incorporated into the dataset every year, with national validation taking place twice a year.

Figure 6.  

Temporal distribution of the ZNIEFF dataset for species from 1757 to 2019.