Meetnetten.be - Population counts for dragonflies in Flanders, Belgium

Study Extent

Gevlekte witsnuitlibel - Leucorrhinia pectoralis - The Yellow-spotted whiteface occurs in Flanders moderately nutrient-rich pools and bogs.. The water surface of the larval habitat is unshaded and dominated by submerged vegetation in different succession stages. This species is followed up by sitecounts. Hoogveenglanslibel - Somatochlora arctica - The Northern Emerald favours Sphagnum peat bogs, transition mires and raised bogs, with only very small amount of open water. This species is followed up by sitecounts. Kempense heidelibel - Sympetrum depressiusculum - The Spotted Darter prefers open and shallow habitats that dry out in late summer (-September-October) andare flooded again in late spring. The eggs are oviposited in plant tissues and overwinter as such. It is important that the riparian vegetation is open and sparse. The species therefore avoids dense reed vegetation. The Spotted Darter is monitored by sitecounts. Maanwaterjuffer - Coenagrion lunulatum - The Crescent bluet occurs at oligotrophicfens in a small number of heathlands in the notheastern part of Flanders. This species is followed up by sitecounts. Speerwaterjuffer - Coenagrion hastulatum - The pearhead Bluet prefersnea moderately nutrient-poor and weak buffered fens and pools. In Flanders, the species can only be found in a few areas in the Limburgse Kempen. The Spearhead Bluet damselfly is monitored by a site count.

Sampling

Sampling was done using the protocol described in De Knijf et al. (2019) and explained to volunteers in Ledegen et al. (2017). Gevlekte witsnuitlibel - Leucorrhinia pectoralis All individuals above a water body or in its immediate vicinity are counted for 1 hour.. The area counts are done at least twice within the peak flight time, with good dragonfly weather, between 11h and 16.30h. A first visit between 20 May and 10 June, a second between 1 and 30 June. Hoogveenglanslibel - Somatochlora arctica All individuals are counted for 1 hour at its larval habitat or in the immediate vicinity .. The area counts are done at least twice within the peak flight time, with good dragonfly weather, between 11h and 16.30h. A first visit between 20 May and 30 June, a second between 1 June and 31 July. Kempense heidelibel - Sympetrum depressiusculum All individuals in a given zone (=area), both near water and surrounding land habitat, are counted for 1 hour. The area counts are done at least twice within the peak flight time, with good dragonfly weather. A first visit between 1 and 10 August, a second between 11 and 31 August. Maanwaterjuffer - Coenagrion lunulatum All individuals above a water body or in its immediate vicinity are counted for 1 hour. The area counts are done at least twice within the peak flight time, with good dragonfly weather, between 11h and 16.30h. A first visit between 20 April and 30 April, a second between 1 May and 20 May. Speerwaterjuffer - Coenagrion hastulatum All adult individuals (i.e., no newly hatched or tenured animals) at the water feature counted for 1 hour. The counts are done at least twice within the peak of the flight time and with good dragonfly weather between 11.00 and 16.30 hrs. A first visit is made between 15 and 31 May, a second between 1 and 20 June.

Quality Control

Speerwaterjuffer - Coenagrion hastulatum All adult individuals (i.e., no newly hatched or tenured animals) at the water feature counted for 1 hour. The counts are done at least twice within the peak of the flight time and with good dragonfly weather between 11.00 and 16.30 hrs. A first visit is made between 15 and 31 May, a second between 1 and 20 June.

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. 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.
5. The Darwin Core views are connected to the INBO IPT and documented with metadata.
6. The dataset is published and registered with GBIF.

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 population count protocol, for which there are 6 target species.

1. Animalia
   rank: kingdom
2. Leucorrhinia pectoralis
   common name: Yellow-spotted Whiteface rank: species
3. Somatochlora arctica
   common name: Northern Emerald rank: species
4. Sympetrum depressiusculum
   common name: Spotted Darter rank: species
5. Coenagrion lunulatum
   common name: Crescent Bluet rank: species
6. Coenagrion hastulatum
   common name: Spearhead Bluet rank: species
7. Arthropoda
   rank: phylum
8. Insecta
   rank: class
9. Odonata
   rank: order

Flanders, Belgium