S.E.H. Conservation Committee Blog

 

In November 2009 the new Red Lists on Dutch amphibian and reptiles were presented by RAVON (formal publication date is 2007). This report presents, apart from the list using official Dutch criteria, for the first time Red Lists following the criteria of IUCN, so that the situation in The Netherlands can be compared with that in other countries.

 

 

 

Amphibians

All 16 species regularly reproducing in The Netherlands were assessed according to the criteria of the Dutch government. The threatened species are being subdivided in four categories as follows (there are no species in the category Extinct in The Netherlands):

1 Critically endangered (Bombina variegata)

3 Endangered (Salamandra salamandra, Pelobates fuscus, Hyla arborea)

3 Vulnerable (Triturus cristatus, Lissotriton helveticus, Alytes obstetricans)

1 Susceptible (Bufo calamita)

The Red List comprises 8 species (50% of the assessed species). The other 8 species are Not threatened at present. The IUCN Regional Red List consists of the following categories of species: 3 Endangered (Salamandra salamandra, Pelobates fuscus, Bombina variegata) and 2 Vulnerable (Alytes obstetricans, Bufo calamita). The other 11 species belong to Least Concern.

The most important causes of threat for half the Dutch amphibian fauna are:

* Lowering of ground water levels: all species are more or less affected

* Loss and fragmentation of habitats: almost all species are affected because of their low mobility.

* Eutrophication and acidification.

* (Shrub) encroachment of habitat: especially thermophilic and psammophilic species as Bombina variegata, Alytes obstetricans and Pelobates fuscus are affected.

 

Reptiles

All 7 species regularly reproducing in The Netherlands were assessed according to the criteria of the Dutch government. The 2007 Red List for Reptiles includes the following numbers of species per category (there are no species in the category Extinct in The Netherlands):

1 Critically endangered (Podarcis muralis)

1 Endangered (Coronella austriaca)

3 Vulnerable (Lacerta agilis, Natrix natrix, Vipera berus)

1 Susceptible (Zootoca vivipara)

The Red List comprises 6 species (86% of the assessed species). Only one species (Anguis fragilis) is Not threatened at present.The IUCN Regional Red List consists of two species of the category Vulnerable (Podarcis muralis, Coronella austriaca). The other 5 species belong to Least Concern.

 

The most important causes of threat for the Dutch reptile fauna are:

* Loss and fragmentation of habitats: almost all species are affected because of their low mobility. The surface of prime reptile habitats as heathlands and raised bogs has decreased by over 90%.

* (Shrub) encroachment of habitat: in combination with a lack of nature management is the cause of recent habitat loss and an increasing fragmentation. Between 1983 and 2000 still 8.000 hectares of heathland changed into forest!

* Unsuitable management: especially practices as sod cutting and grazing introduced on an intensive and large scale have had a tremendous negative effect on reptiles, particularly in the eighties and nineties.

 

The complete title of the report is: Delft, J.J.C.W. van, R.C.M. Creemers & A. Spitzen-van der Sluijs, 2007. Basisrapport Rode Lijsten Amfibieën en Reptielen volgens Nederlandse en IUCN-criteria. – Stichting RAVON, Nijmegen, in opdracht van Directie Kennis, Ministerie van LNV. The report (in Dutch with English summary) can be found here.

Last November RAVON also presented the last Atlas of the amphibians and reptiles of the Netherlands. The book is published in the renowned series “Nederlandse Fauna” (“Netherlands Fauna”), published by the National Museum of Natural History Naturalis and the European Invertebrate Survey-The Netherlands.

The Atlas consists of 480 pages with 420 color photos, 150 maps and many graphs, tables and drawings and it is based on over 450,000 records! It also includes a CD with the calls of all the Dutch frogs and toads. The book is in Dutch, with English summaries. Besides extensive species accounts of the 16 indigenous amphibians and 7 indigenous reptiles also species accounts of three exotic species (Triturus carnifex, Rana catesbeiana and Trachemys scripta elegans) are included as well as an extensive chapter on the stranded sea turtles (4 species). Ten chapters deal with subjects as taxonomy, amphibians and reptiles in cultural history, history of herpetology in The Netherlands, ecology and nature management. The Atlas costs 49.95 euros and it can be ordered here.

 

The complete title of the Atlas is: Creemers, R.C.M. & J.J.C.W. van Delft, (RAVON) (Eds), 2009. De amfibieën en reptielen van Nederland. – Nederlandse Fauna 9. Nationaal Natuurhistorisch Museum Naturalis, European Invertebrate Survey – Nederland, Leiden.