Meetnetten.be - Chorus counts for Amphibia in Flanders, Belgium

Frederic Piesschaert1, Jeroen Speybroeck1, Dimitri Brosens2, Toon Westra1, Peter Desmet1, Hannes Ledegen3, Sam Van de Poel3, Marc Pollet1, Dimitri Brosens4

1 Research Institute for Nature and Forest (INBO), , Belgium; 2 Research Institute for Nature and Forest (INBO)/ Belgian Biodiversity Platform, , Belgium; 3 Natuurpunt, , Belgium; 4 

Corresponding author(s): Frederic PiesschaertJeroen SpeybroeckDimitri BrosensToon Westra (toon.westra@inbo.be)Peter DesmetHannes Ledegen (hannes.ledegen@natuurpunt.be)Sam Van de Poel (sam.vandepoel@natuurpunt.be)Marc Pollet, Dimitri Brosens (dimitri.brosens@inbo.be)

Received {date}; Revised {date}; Accepted {date}; Published {date}

Citation: Combination of authors, year of data paper publication (in parentheses), Title, Journal Name, Volume, Issue number (in parentheses), and doi of the data paper.

Resource Citation

Piesschaert F, Speybroeck J, Brosens D, Westra T, Desmet P, Ledegen H, Van de Poel S, Pollet M (2023). Meetnetten.be - Chorus counts for Amphibia in Flanders, Belgium. Version 1.17. Research Institute for Nature and Forest (INBO). Samplingevent dataset. https://doi.org/10.15468/d4bu8j https://doi.org/10.15468/d4bu8j

Abstract

Meetnetten.be - Chorus counts for Amphibia in Flanders, Belgium is a sampling event dataset published by the Research Institute of Nature and Forest (INBO). It is part of the Meetnetten.be suite of monitoring networks for priority species in Flanders, in which data are collected at fixed locations using a standardized protocol (https://meetnetten.be). This dataset contains site counts for 3 priority species (Hyla arborea, Epidalea calamita and Pelobates fuscus), as well as other amphibian species observed during sampling. Here, it 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) and for each occurrence an occurrenceID, the number of recorded individuals,  status (present/absent) 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: as these are sensitive priority species, location information is generalized to 1, 5 or 10 km 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.
For all published Meetnetten.be datasets, see https://www.gbif.org/dataset/search?project_id=meetnetten.be

Keywords: Samplingevent, Toads, frogs, freshwater, monitoring, priority species, Samplingevent

Project details

Project title: Meetnetten.be
Personnel: Frederic Piesschaert
Funding: Flemish Government
Study area descriptions/descriptor: Flanders, Belgium
Design description: Each monitoring network consists of fixed sample locations in which target species are counted based on a standardized protocol. Data collection relies mainly on specialized volunteers, coordinated by the NGO Natuurpunt Studie. Fieldwork is planned and monitored with the web tool https://meetnetten.be, which is also used for entering the collected data.

Data published through GBIF: https://ipt.inbo.be/resource?r=meetnetten-amphibia-roepkoren-occurrences

Taxonomic coverage

General taxonomic coverage description: The target Caudata species for Meetnetten.be are listed at https://meetnetten.be/#group-1. Other salamanders observed during the sampling are also included. This dataset covers the amphibian chorus counts protocol, for which there are 3 target species.
Taxonomic ranks
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Caudata, Anura
Species: Hyla arborea, Epidalea calamita, Pelobates fuscus

Spatial coverage

General spatial coverage: Flanders, Belgium
Coordinates: 50°40'12''N and 51°30'36''N Latitude; 2°31'48''E and 5°56'24''E Longitude 

Temporal coverage: January 1, 2016 - December 31, 2022

Methods

Method step description: 
- . 	Researchers from INBO and Natuurpunt Studie define and document the appropriate sampling protocol for the target species.
- . 	Fieldwork is planned and coordinated by Natuurpunt Studie, using https://meetnetten.be.
- . 	Data are collected in the field by specialized volunteers, using the predefined sampling protocol.
- . 	Volunteers enter the collected data in https://meetnetten.be.
- . 	A custom SQL view is created in the meetnetten.be database to map the original data to Darwin Core as an event core with an occurrence extension
- . 	The Darwin Core views are connected to the INBO IPT and documented with metadata.
- . 	The dataset is published and registered with GBIF.
Study extent description: 1. Pelobates fuscus, or the common spadefoot toad, is found in fishless cattle drinking pools and relatively nutrient-rich ponds, but also in cut brook and river meanders in a fairly open, sandy environment. These are often water features in (buffered) heathlands, but also near dikes and even vegetable gardens and extensively managed fields. This type of habitat is rare in Flanders. The common spadefoot currently only occurs in the central part of Limburg.

2. Hyla arborea, or the common tree frog, is found in the scrubland of the Limburgse Kempen, a restricted section of the Antwerpse Kempen near the Belgian-Dutch border, and the dunes of the Zwin. In recent years, the Flemish population has increased.

3. Epidalea calamita or the Natterjack toad is a true pioneer species that thrives  in dynamic environments. The species reproduces from April to August, when the animals gather in breeding pools and the males call loudly.
Sampling description: For the tree frog and spadefoot toad the number of calling males is counted in the reproductive habitat at least twice a year.
1. Male Pelobates fuscus call from the bottom of the waterbody. The calls being fairly weak, counting the exact number of calling males by ear can be challenging. This is particularly the case when other anurans such as Hyla arborea are calling simultaneously. Therefore, the use of an underwater hearing device or hydrophone is advocated. Each waterbody is investigated with waders, in order to approach the calling animals upto hearing distance. 

2. Hyla arborea: Monitoring in the framework of the Tree Frog Monitoring Network is done by counting the number of calling males, or in some cases, by estimating the number.  

3. For the Natterjack toad monitoring network, calling choruses need to be monitored three times. The number of calling males is counted or in some cases, when the population turns out to be too large, estimated.

The number of calling males is counted exactly at each visit. For up to 50 animals the sounds are still good to distinguish and localize so that this is easy (Bauwens & Speybroeck, 2014; Groenveld et al., 2011). With more animals a more rough estimate can be given.

Sampling was done using the protocol described in De Bruyn et al. (2015), updated by Speybroeck et al. (2020), and explained to volunteers in Lewylle et al. (2017).
Quality control description: Data are collected using a predefined sampling protocol.

Datasets

Dataset description
Object name: Darwin Core Archive Meetnetten.be - Chorus counts for Amphibia in Flanders, Belgium
Character encoding: UTF-8
Format name: Darwin Core Archive format
Format version: 1.0
Distribution: https://ipt.inbo.be/archive.do?r=meetnetten-amphibia-roepkoren-occurrences
Publication date of data: 2023-12-04
Language: English
Licences of use: Public Domain (CC0 1.0)

Metadata language: English
Date of metadata creation: 2020-07-29
Hierarchy level: Dataset

References
Luc De Bruyn, Jeroen Speybroeck, Dirk Maes, Geert De Knijf, Thierry Onkelinx, Frederic Piesschaert, Marc Pollet, Toon Westra & Paul Quataert (2015). Monitoringsprotocol kikkers en padden. Rapporten van het Instituut voor Natuur- en Bosonderzoek 2015 (INBO.R.11336466). Instituut voor Natuur- en Bosonderzoek, Brussel.
Van de Poel S., I. Lewylle, M. Segal & H. Ledegen. 2018. Veldwerkhandleiding Rugstreeppad. Natuurpunt Studie, Mechelen
I. Lewylle, M & H. Ledegen. 2018. Veldwerkhandleiding Boomkikker. Natuurpunt Studie, Mechelen
Speybroeck J, De Bruyn L, Van de Poel S, Ledegen H, Westra T (2020). Monitoringsprotocol amfibieën en reptielen. Versie 2.0. Rapporten van het Instituut voor Natuur- en Bosonderzoek 2020 (22). Instituut voor Natuur- en Bosonderzoek, Brussel. https://doi.org/10.21436/inbor.17954118