Meetnetten.be - Larvae and metamorph counts for Amphibia in Flanders, Belgium

Study Extent

1. Triturus cristatus, or the great crested newt, is our largest native newt. It is widespread in Flanders, especially in wide river valleys and in locations with (many) old bomb pits. Although the crested newt appears to react positively to the construction of new pools near existing populations in nature reserves, it seems to be declining in the outlying area. This species prefers fish-free pools with sun-drenched banks and rich underwater vegetation located in a varied terrestrial habitat. These include cattle drinking pools in meadows with many small landscape elements, large (spring) pools in more wooded habitats, cut-off rivers, but also old quarries. 2. 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. 3. 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.

Sampling

In June - mid-July, larvae are counted to determine reproductive success. In order to quantify the larvae present, a net should be dipped per 2 m of shoreline (where possible and suitable). Each two-metre piece (one dip movement), the number of larvae is noted. In total, you feed a minimum of 5 and a maximum of 30 scoop movements. 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

Data are collected using a predefined sampling protocol.

Method steps

1. Researchers from INBO and Natuurpunt Studie define and document the appropriate sampling protocol for the target species.
2. Fieldwork is planned and coordinated by Natuurpunt Studie, using https://meetnetten.be.
3. Data are collected in the field by specialized volunteers, using the predefined sampling protocol.
4. Volunteers enter the collected data in https://meetnetten.be.
5. 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
6. The Darwin Core views are connected to the INBO IPT and documented with metadata.
7. The dataset is published and registered with GBIF.

The target 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 fyke protocol, for which there are 3 target species.

1. Animalia
   rank: kingdom
2. Chordata
   rank: phylum
3. Amphibia
   rank: class
4. Caudata
   rank: order
5. Anura
6. Triturus cristatus
   common name: great crested newt rank: species
7. Hyla arborea
   common name: common tree frog rank: species
8. Pelobates fuscus
   common name: common spadefoot toad rank: species

Flanders, Belgium