The nationwide ‘ZNIEFF’ inventory in France: a free dataset of more than one million synthesised species data in zones of high ecological value

In France, a ‘natural zone of ecological, faunistic or floristic value’ (Zone Naturelle d'Intérêt Écologique, Faunistique et Floristique - ZNIEFF) is a natural area regionally known for its remarkable ecological characteristics. The ZNIEFF inventory is a naturalist and scientific survey program launched in 1982 by the Ecology Ministry, with support from the French National Museum of Natural History (MNHN).
 This paper describes the ZNIEFF national dataset, which comprises 1 013 25 synthesised data for various animal (38%), vegetal (59%) and fungus (2%) species in terrestrial and marine zones (the last download took place on 26 May 2020). A total of 19 842 sites throughout continental France as well as in the overseas departments and territories (Guadeloupe, Martinique, Mayotte, La Réunion, French Guiana, Saint-Martin, Saint-Barthélemy and Saint-Pierre-et-Miquelon) are included in the ZNIEFF dataset (last download: 26 May 2020). This dataset is now available in open access.
 All data were collected by skilled naturalists using professional protocols over almost 40 years. They consist mainly of observations of rare, threatened or endemic species, all validated by regional experts. Data is updated twice a year after national validation. Some of the observed of species, the so-called ‘trigger species’ or ‘determinant’ species, are of central interest for a site to be considered a ZNIEFF (zone of high ecological value). This concerns more than 35 000 taxa, mainly angiosperms, insects, fungi, birds and fish.


Introduction
In France, a 'natural zone of ecological, faunistic or floristic value' (Zone Naturelle d'Intérêt Écologique, Faunistique et Floristique -ZNIEFF) is a natural area regionally known for its remarkable ecological characteristics (Horellou et al. 2017). The ZNIEFF inventory is a naturalist and scientific survey program launched in 1982 by the Ecology Ministry, with support from the French National Museum of Natural History (MNHN). The ZNIEFF programme was then integrated in French environmental law on 8 January 1993 (Art. 23,. The regulatory framework for ZNIEFFs was reinforced over time through several circulars, decrees and laws. The aim of this inventory is to use naturalist knowledge obtained in the field to determine the location of natural sites (terrestrial and marine) with high ecological value in France and to assist in land-planning issues. This program is conceptually similar to the Key Biodiversity Areas (KBA) initiative developed on the international level (IUCN 2016), but with a more regional and national scale of issues.
The ZNIEFF inventory is included in the National Inventory of Natural Heritage (INPN) (Pon cet 2013) as part of the national information system for sharing observational data on biodiversity in France (Système d'Information sur la Nature et les Paysages, SINP). The ZNIEFF species dataset is therefore now available in open access in both national (INPN-OpenObs) and global (GBIF) biodiversity web platforms.

General description
Purpose: 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).
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 characterized by remarkable environmental features (e.g. a moor on serpentine). The ZNIEFF inventory is central for prioritizing 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 item when defining the French National Strategy for the Creation of Protected Areas (SCAP). In 1993, the ZNIEFF inventory facilitated the implementation of the European Habitat 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 knowledge on the national level for almost 40 years.

Additional information:
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 the 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, urbanization). Only data concerning species (not habitats) will be presented in this datapaper, as habitat data do not yet benefit from viewing and downloading tools on 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 or and 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 free diffusion dataset on the INPN website and the GBIF portal.

Project description
Personnel: In order to guarantee the consistency of the information, data is collected using a common framework (Horellou et al. 2017) defined jointly by a scientific and technical coordination team based in the French National Museum of Natural History (UMS PatriNat) and the Ecology Ministry. The observations are transmitted by the wide-ranging naturalist network in France, including independent professional and amateur naturalists, associations for nature studies and protection, public institutions, contractors (private sector), learned societies, etc. The Regional Scientific Councils for Natural Heritage (CSRPN) validate the local inventories in close conjunction with the regional services of the Ecology Ministry and their scientific secretariat 'ZNIEFF' before transmission to the MNHN for validation to ensure its technical and scientific consistency. The data is then sent to the ZNIEFF database via a web application specifically designed for this purpose.

Funding:
The Ecology Ministry coordinates the regional services and provides financial support for the annual operation of the ZNIEFF programme.

Sampling methods
Sampling description: Sampling is focused on areas of high biodiversity identified on the regional scale. These zones (19 842 registered as ZNIEFFs on May 2020; Table 1) are pre-identified based on the knowledge of field naturalists, often through the primary study of vegetation, but occasionally also on abiotic characteristics (e.g. a moor on a serpentine substrate). The subsequent inventory of various taxa on these sites helps to confirm (or not confirm) their value for conservation. ZNIEFF data come mainly from direct field observations, but can also rely on literature sources, collections and other databases. A great variety of sampling methods and protocols are used to collect data, depending on the environment and the taxon concerned.
Quality control: The dataset presented in this publication is managed by UMS PatriNat (OFB/CNRS/MNHN), the unit also responsible for the National Inventory of Natural Heritage (INPN). The INPN is part of the SINP, i.e. the French national information system for sharing observational data on biodiversity. This information system guarantees the traceability of data, authorship and normalized standards of data and metadata.
Before integration and dissemination on the INPN website, a series of validation checks are systematically performed (Jomier et al. 2019). The first category of checks consists of validating compliance with standard data and metadata formats, i.e. all mandatory fields completed, use of required formats, repositories (including the geographic and taxonomic repositoires), classifications and lists of values. The second category of checks consists of validating the consistency (i.e. the absence of logical incompatibility) within the data, within the metadata and between the data and the metadata. As an example, the observation start date must be less than or equal to the observation end date. ZNIEFF data are updated two times a year.
The INPN provides the data directly to the GBIF portal in order to make the data available on the international level.
All taxa are identified by experienced naturalists prior to the validation by the regional scientific councils (CSRPN). The dataset producers are responsible for the reliability of the identification.

Geographic coverage
Description: The inventory covers the marine, terrestrial and freshwater environments of all administrative regions of continental France and its overseas territories (five overseas departments: Guadeloupe, Martinique, Mayotte, La Réunion, French Guiana and three overseas territories: Saint-Martin, Saint-Barthélemy and Saint-Pierre-et-Miquelon) (Fig. 1).
The description and mapping of the area are specified by the ZNIEFF method and the geographic boundaries of each ZNIEFF must have a scientific basis (ecological, consistent with the heritage and functional value of the area, with particular reference to criteria for the distribution of habitats, vegetation, geomorphology, land use, etc.

Taxonomic coverage
Description: The ZNIEFF inventory focuses on all fauna, flora and fungus taxa, with a special emphasis on rare, threatened or endemic taxa of the taxonomic groups which are best studied by naturalists. The considered taxa are those considered indigenous to French territories and they are examined on the specific and infra-specific levels (Horellou et al. 2014).
The taxonomy complies with the standards of the national repository TAXREF for the fauna, flora and fungi of continental France and the overseas departments and territories ( Gargominy et al. 2019). TAXREF assigns a unique, unambiguous and (wherever possible) consensual scientific name to all species occurring in these territories. A new version of TAXREF is published yearly on the INPN website (link above) and the GBIF portal (https:// www.gbif.org/dataset/0e61f8fe-7d25-4f81-ada7-d970bbb2c6d6).
More than 35 000 taxa (species and subspecies) have been inventoried in ZNIEFFs to date, which represents approximately 19% of the number of species currently listed in France (INPN 2019). The taxa targeted by the ZNIEFF inventory usually have high conservation value on the national and supra-national levels (taxa which are geographically localized, endemic, at the limit of the range, threatened on the regional, national or international level, etc.). The taxonomic groups with the highest number of taxa inventoried are, in decreasing order, angiosperms (13 312), insects (8 823), fungi (3 033), birds (1 503) and fish (1 128) ( Table 2, Figs 2, 3, 4). These groups have a significant percentage of endemic or subendemic taxa and species assessed as threatened according to the national Red List (Table 2).

Temporal coverage
Notes: 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 (Hore llou et al. 2017). These phases corresponded to important methodological changes. Since 2017, the ZNIEFF inventory is continuously updated (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 observed in Fig. 6, new data are incorporated into the dataset every year, with national validation taking place twice a year. The field indicates whether the taxon is regionally sensitive, i.e. the data should not be disseminated specifically to avoid harm to the taxon. This is a different level of sensitivity from that explained in the General description of the datapaper. This regional sensitivity implies blurred data.

Usage licence
dataGeneralizations When the data is considered sensitive (cf. informationWithheld), this field indicates the blurring applied to the data.

Additional information
When using the data from the ZNIEFF inventory, synthesised species data (see Data Resources) should be associated with the perimeters of the zones (see the Geographic coverage section above). The X, Y coordinates in the dataset downloadable from the GBIF portal correspond with the centroids of the zones. It is therefore necessary to link the synthesised data and the perimeters with the common field, which is the identifier of the ZNIEFF ('Event ID' in the dataset and 'NM_SFFZN' in GIS files).
These data can be used for all types of analyses and studies on key biodiversity areas, protected areas and ecological networks. They can also be used for maps of rare species, distribution atlases, etc. These data alone are not suitable for precise monitoring of populations nor for establishing temporal trends of distribution.
Caution is advised in that there may be differences in inventory intensity and species groups studied depending on the region. Comparison of species occurrence (and even more so of richness) among sites is more relevant within a given region and should be considered with caution on the national level.
amateur naturalists, associations for nature studies and protection, public institutions, contractors (private sector), learned societies, etc. We also wish to thank DREAL/DEAL/ DRIEE IDF/DAF, ZNIEFF managers on the regional level and all the Regional Scientific Councils (CSRPN) whose role is essential to guarantee the scientific validity of the ZNIEFFs. The Ecology Ministry is here thanked for its support and monitoring for almost 40 years. Finally, we thank Jean Ichter, who helped on the data quality section, and Mathieu Clair, Nicolas Boulain, Benjamin Ledentec, Sophie Pamerlon and Sylvain Morin from the "Data" and "IT applications" teams of UMS PatriNat (OFB/CNRS/MNHN) and GBIF France.  Taxonomic coverage of the ZNIEFF inventory (number of taxa and data records per group) for 'taxonomic' groups that have more than 100 000 data records (the last download from INPN took place on 26 May 2020).  Taxonomic coverage of the ZNIEFF inventory (number of taxa and data records per group) for 'taxonomic' groups that have less than 100 000 and more than 1 000 data records (the last download from INPN took place on 26 May 2020).
Taxonomic coverage of the ZNIEFF inventory (number of taxa and data per group) for 'taxonomic' groups that have less than 1 000 data (the last download from INPN took place on 26 May 2020).
Temporal distribution of the ZNIEFF dataset for species from 1757 to 2019. 16