IMIS - Marine Onderzoeksgroepen

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), the length of the transect (in the measurement or fact extension) and for each occurrence an occurrenceID, the number of recorded individuals, status (present/absent), life stage, sex 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
The target dragonfly species for Meetnetten.be are listed at https://meetnetten.be/#group-6. Other dragonflies observed during the sampling are also included. This dataset covers the transect protocol, for which there are 3 target species.
Sampling was done using the protocol described in De Knijf et al. (2019) and explained to volunteers in Ledegen et al. (2017). 1. Calopteryx virgo (Beautiful demoiselle / Bosbeekjuffer): a sample of 30 populations is monitored, of which 10 are counted each year. In the year a population is counted, at least three transect counts are carried out when flying adults occur (May 20 - Aug 20), with good dragonfly weather, between 11h and 16:30h. A transect is located along the shore and is at least 100m, maximum 500m long (depending on the amount of suitable habitat). During a count, the transect is walked slowly and all adults are counted up to a distance of 2 m on the bank and 3 m above the water. 2. Coenagrion pulchellum (Variable Damselfly / Variabele waterjuffer): a sample of 30 populations is monitored, of which 10 are counted each year. In the year a population is counted, at least two transect counts are carried out when flying adults occur (May-June), in good dragonfly weather, between 11h and 16:30h. A transect is located along the shore and is about 100 m long (depending on the amount of suitable habitat). During a count, the transect is walked slowly and all adults are counted up to a distance of 2 m on the bank and 3 m above the water. 3. Aeshna isoceles (Green-eyed Hawker / Vroege glazenmaker): a sample of 30 populations is monitored, of which 10 are counted each year. In the year a population is counted, at least two transect counts are carried out when flying adults occur (20 May - 30 June), with good dragonfly weather, between 11h and 16:30h. A transect is located along the shore and is about 100 m long (up to a maximum of 500 m depending on the amount of suitable habitat). During a count, the transect is walked slowly and all adults are counted up to a distance of 2 m on the bank and 5 m above the water.