Butterfly monitoring scheme in Flanders, Belgium

Dirk Maes; Frederic Piesschaert; Dimitri Brosens; Peter Desmet

doi:10.15468/wwrgcd

Butterfly monitoring scheme in Flanders, Belgium

Citation

Maes D, Piesschaert F, Brosens D, Desmet P (2022). Butterfly monitoring scheme in Flanders, Belgium. Version 1.6. Research Institute for Nature and Forest (INBO). Sampling event dataset https://doi.org/10.15468/wwrgcd accessed via GBIF.org on 2024-11-03.

Description

Butterfly monitoring scheme in Flanders, Belgium is a sampling event dataset published by the Research Institute of Nature and Forest (INBO). This dataset contains transect data for butterfly species, collected using a standardized protocol since 1991. Data from 1991-2014 were collected in the INBO Vlinderdatabank (Maes et al. 2016), but have since been migrated to the meetnetten.be database, where new observations are recorded. Here, the dataset is published as a standardized Darwin Core Archive and includes for each sampling event an eventID, date, location and sampling protocol (in the event core), the cloudiness, temperature, and wind force at the time of the event (in the measurement or fact extension) and for each occurrence an occurrenceID, the number of recorded individuals in a transect, lifestage, status (present/absent), vernacular and scientific name (in the occurrence extension). Issues with the dataset can be reported at https://github.com/inbo/meetnetten-occurrences/issues

Generalized and/or withheld information: location information is generalized to 5 Universal Transverse Mercator (UTM) grid cells. Original locations are available upon request.

We have released this dataset to the public domain under a Creative Commons Zero waiver. We would appreciate it if you follow the INBO norms for data use (https://www.inbo.be/en/norms-data-use) when using the data. If you have any questions regarding this dataset, don't hesitate to contact us via the contact information provided in the metadata or via opendata@inbo.be.

Purpose

Since 1991, a butterfly monitoring scheme has been up and running in the northern part of Belgium. The number of butterfly transects remained much smaller than in the UK or in the Netherlands, but thanks to novel statistical techniques, trends can now be calculated for more common species, even with a relatively low number of butterfly transects. In total, 105 transects have been counted with different intensities. Twenty of these transects yielded data of high to very high quality (i.e., are counted a large number of years and regularly throughout the year). One third of the transects is located in an agricultural environment, a quarter in open semi-natural areas, another quarter in woodland and the remaining transects are in urban areas. Over the 29 years of butterfly monitoring, 46 species have been observed of which Meadow Brown (Maniola jurtina), Gatekeeper (Pyronia tithonus), Small White (Pieris rapae), Green-veined White (Pieris napi) and Essex Skipper (Thymelicus lineola) were the most counted ones. Six species are increasing significantly between 1991-2019: Red Admiral (Vanessa atalanta), Speckled Wood (Pararge aegeria), Brimstone (Gonepteryx rhamni), Comma (Polygonia c-album), Holly blue (Celastrina argiolus) and Orange-tip (Anthocharis cardamines) while five others are decreasing significantly: Meadow Brown (Maniola jurtina), Large Skipper (Ochlodes sylvanus), Small Tortoiseshell (Aglais urticae), Gatekeeper (Pyronia tithonus) and Essex Skipper (Thymelicus lineola).

Sampling Description

Study Extent

The Flemish butterfly monitoring scheme is the counting of butterflies in a standardized manner, which allows us to determine trends of various species over longer periods in time. In Flanders the butterfly monitoring scheme started modestly in 1991 and it actually always remained so. With a dozen butterfly routes that are walked annually, using new statistical techniques, we are able to establish a trend for the most common butterflies in Flanders (see Maes et al. 2020a; Maes et al. 2020b).

Sampling

Sampling was done using the protocol described in Maes et al. (2019). Butterfly transects are in principle up to 1 km long and are divided into sections of 50 m (cf. Pollard & Yates 1993; van Swaay et al. 2008; van Swaay et al. 2011; Sevilleja et al. 2019). The length of 1000 m with up to 20 sections is a target that depends on the size of the area. The route is drawn in on a map or read using a GPS device, for example by using the "route" option of the mobile applications of www.waarnemingen.be (iObs and ObsMapp) or via the Track-Kit application. By using markers or landmarks on the transect, the different sections can be delineated so that the transect can be easily replicated by others. If, for some reason, a section is removed from the transect (e.g. no longer accessible, became completely unsuitable), then this section can either be replaced by a new section or no longer be counted (Onkelinx et al. 2017). In both cases, this must be documented and reported to the monitoring network coordinator so that it can be taken into account in the analyses of the data. Such sections are set to inactive on the input portal, but the data and location remain available for interpretation of historical data. The original numbering of these inactive sections, however, is not reused for the new sections so that there is no confusion in interpreting the data. The location of the different areas is visible at 5 x 5 km² square level to everyone on www.meetnetten.be. The details of the locations are only visible to people who are registered and approved for the monitoring network. Transect counts are conducted between 10-17h in suitable weather conditions for butterflies: temperature ≥ 17°C without clouds or temperature ≥ 20°C if cloudy, wind force ≤ 4 Beaufort and no precipitation. The counting itself is done by walking the transect at a pace that allows the identification of species by sight and noting the number of individuals per section of 50 meters. Sometimes it can be useful to catch a few less easily distinguishable species (e.g. the cabbage whites or skippers) at the same time and to name them at the end of each section. Only butterflies flying in an imaginary cage of 2.5 m left, 2.5 m right, 5 m above and 5 m in front of you are counted. In the Flemish butterfly monitoring scheme, weekly counts are conducted, when weather permits between April 1 and September 30. This makes a total of 26 weeks.

Quality Control

Data are collected using a predefined sampling protocol.

Method steps

Data are collected in the field by specialized volunteers, using the predefined sampling protocol.
Volunteers enter the collected data in https://meetnetten.be or via an app in the field.
A custom SQL view is created in the meetnetten.be database to map the original data to Darwin Core as an event core, occurrence extension and measurement or fact extension.
The Darwin Core views are connected to the INBO IPT and documented with metadata.
The dataset is published and registered with GBIF.

Taxonomic Coverages

The dataset covers 51 species. Nomenclature is according to Wiemers et al. (2018).

Animalia
common name: animals rank: kingdom
Arthropoda
rank: phylum
Insecta
common name: insects rank: class
Lepidoptera
common name: butterflies rank: order

Geographic Coverages

Flanders, Belgium

Bibliographic Citations

Maes D, Vanreusel W, Herremans M, Vantieghem P, Brosens D, Gielen K, Beck O, Van Dyck H, Desmet P, Vlinderwerkgroep Natuurpunt (2016) A database on the distribution of butterflies (Lepidoptera) in northern Belgium (Flanders and the Brussels Capital Region). ZooKeys 585, 143-156. https://doi.org/10.3897/zookeys.585.8019 -
Maes D, Ledegen H, Van de Poel S & Westra T (2019) Monitoringsprotocol Dagvlinders: Versie 2.0. Rapporten van het Instituut voor Natuur- en Bosonderzoek 2019 (56). Instituut voor Natuur- en Bosonderzoek, Brussel. https://doi.org/10.21436/inbor.16744530 -
Maes D, Piesschaert F, T'jollyn F, Van Dyck H (2020a) Dagvlindermonitoring in Vlaanderen. 1991-2019. Instituut voor Natuur- en Bosonderzoek, Brussel. https://doi.org/10.21436/inbor.1834447 -
Maes D, Piesschaert F, T’jollyn F, Van Dyck H (2020b) Dagvlindermonitoring in Vlaanderen. Wat leren we van 29 jaren vlinders tellen? Natuur.focus 19, 52-63. -
Ledegen H, Veraghtert W & Van de Poel S (2018) Veldwerkhandleiding dagvlinders. Natuurpunt Studie, Mechelen. -
Wiemers M, Balletto E, Dincă V, Fric ZF, Lamas G, Lukhtanov VA, Munguira ML, van Swaay CAM, Vila R, Vliegenhart A, Wahlberg N, Verovnik R (2018). An updated checklist of the European Butterflies (Lepidoptera: Papilionoidea). ZooKeys 811, 9-45. https://doi.org/10.3897/zookeys.811.28712 -

Contacts

Dirk Maes
originator
Research Institute for Nature and Forest (INBO)
BE
email: dirk.maes@inbo.be
userId: http://orcid.org/0000-0002-7947-3788

Frederic Piesschaert
originator
Research Institute for Nature and Forest (INBO)
BE
email: frederic.piesschaert@inbo.be
userId: http://orcid.org/0000-0002-5843-646X

Dimitri Brosens
originator
Research Institute for Nature and Forest (INBO) / Belgian Biodiversity Platform
BE
email: dimitri.brosens@inbo.be
userId: http://orcid.org/0000-0002-0846-9116

Peter Desmet
originator
Research Institute for Nature and Forest (INBO)
BE
email: peter.desmet@inbo.be
userId: http://orcid.org/0000-0002-8442-8025

Dirk Maes
metadata author
Research Institute for Nature and Forest (INBO)
BE
email: dirk.maes@inbo.be
userId: http://orcid.org/0000-0002-7947-3788

Dimitri Brosens
metadata author
Research Institute for Nature and Forest (INBO) / Belgian Biodiversity Platform
BE
email: dimitri.brosens@inbo.be
userId: http://orcid.org/0000-0002-0846-9116

Peter Desmet
metadata author
Research Institute for Nature and Forest (INBO)
BE
email: peter.desmet@inbo.be
userId: http://orcid.org/0000-0002-8442-8025

Dirk Maes
administrative point of contact
Research Institute for Nature and Forest (INBO)
BE
email: dirk.maes@inbo.be
userId: http://orcid.org/0000-0002-7947-3788

Frederic Piesschaert
administrative point of contact
Research Institute for Nature and Forest (INBO)
BE
email: frederic.piesschaert@inbo.be
userId: http://orcid.org/0000-0002-5843-646X