Bat populations thriving

12/07/2011 15:00

Bat populations are thriving in the Netherlands. The 8 species that are being monitored all increase in numbers.

Number of bats

Number of bats

Numbers and geographical distribution

Bat counts show that the 8 bat species, found in places where they spend the summer and hibernate in the larger numbers, are increasing. They make up half of bat species found in the Netherlands.

Populations of Geoffroy’s bats, Natterer’s bats and grey long-eared bats are growing most rapidly. The first two species have grown by an average 13 percent annually (period 1986-2010) and the grey long-eared bats by 9 percent annually. Geoffroy’s bats and grey long-eared bats are rare and only found in the south of the country, in particular in the province of Limburg. Natterer’s bats are fairly common and currently found across the entire country.

The grey long-eared bat is nowadays also found in many places across the country. The populations of Daubenton’s bats and Pond bats grew the least by 3 percent annually. The Daubenton’s bat population has in fact shrunk since 2006.

Few population data are available on 8 other bat species, among which 2 species of common pipistrelles. They live in small, nearly inaccessible hideouts.

Geographical distribution of the Natterer’s bat

Geographical distribution of the Natterer’s bat

Protection

Approximately 50 bat species are found in Europe, of which 16 in the Netherlands. As bats mainly feed on insects, they are regarded as useful for the environment. Many bat species were reduced in numbers after the Second World War when natural landscapes and land use changed and pesticides were used on a large scale.

Three bat species, i.e. the Western Barbastelle, the Greater horseshoe bat and the Lesser horseshoe bat have disappeared altogether from the Netherlands. The mouse-eared bat no longer breeds in the Netherlands, but still hibernates here.

Since 2002, all European (including all Dutch bat species) are protected under the European Habitat Directive, which disallows the wilful killing or disturbing of bat populations and also provides directives for the protection of their habitats and (hibernation) hideouts. Worries about the bat populations have resulted in the proclamation of 2011 as the international year of the bat by UNEP and EUROBATS.

Tom van der Mei and Vilmar Dijkstra (Dutch Mammal Society)