RAVON (NL) - Network Ecological Monitoring Reptiles

Study Extent

Transects are monitored within a two hour timespan. A transect typically consist of only one habitat type.

Sampling

Transects are visited seven times a year under favourable weatherconditions. All encountered reptiles are counted.

Quality Control

The raw data are validated by the coordinator. Statistics Netherlands (CBS) runs an extensive control of the monitor data before calculating trends and indices.

Method steps

1. Trends and indices are calculated by Statistics Netherlands (CBS) using the TRIM-software package. This dataset summarizes the observations per km2 for each year in an occurrence value per species.

All indigenous reptile species in The Netherlands are included in the monitor network.

1. Anguis fragilis
   common name: Slow Worm rank: species
2. Lacerta agilis
   common name: Sand Lizard rank: species
3. Zootoca vivipara
   common name: Viviparous Lizard rank: species
4. Podarcis muralis
   common name: Common Wall Lizard rank: species
5. Coronella austriaca
   common name: Smooth Snake rank: species
6. Natrix natrix
   common name: Grass Snake rank: species
7. Vipera berus
   common name: Adder rank: species

The Netherlands