Download Urbanization Homogenizes Insect Communities

Press release 08.02.2017
Urbanization Homogenizes Insect Communities
Cities eliminate less mobile species and favour those that thrive at higher temperatures. This is
the conclusion of a field study conducted in 81 places in Belgium. ‘For the first time, we see
how urbanization consistently decreases biodiversity on a large scale’, says researcher Frederik
Hendrickx from the Royal Belgian Institute of Natural Sciences (RBINS).
Belgium has a population density of 300 people per square kilometre and is one of the most urbanized countries
in Europe. Worldwide, studies estimate that urbanization will have tripled by 2030. Biologists from the Royal
Belgian Institute of Natural Sciences studied the effect of urbanization on natural species communities using
ground beetles.
Urban heat islands
They compared species composition in rural and urban areas by installing insect traps at 81 places scattered
throughout Belgium. The result: heat tolerating beetle species were much more common in cities compared to
the countryside. Cities are ‘heat islands’ with a lot of heat-absorbing materials, like concrete. Because of the
fragmentation of green areas, cities also appear a dead-end for short-winged beetle species. Those species are
less mobile and not able to migrate to the next green spot when their habitat is converted. In urban Belgium,
there are almost exclusively beetle species with long wings, the study says.
‘Urbanization makes insect faunas uniform’, says biologist Frederik Hendrickx (RBINS). ‘Cities filter species
based on particular traits, like the ability to migrate and to tolerate higher temperatures. That is why you come
across the same few species in every urban area, even in a forest within the city, where you would expect the
same composition as in a forest in the countryside. It is not unlikely that similar mechanisms affect other insect
species, and even plants.’
The study was published in Global Change Biology, and is one of the first to demonstrate this trait-filtering effect
on such an extensive scale. These insights are important for measuring long-term effects for ecosystems and
being able to anticipate them.
Contact
Frederik Hendrickx
Biologist, Royal Belgian Institute of Natural Sciences (RBINS)
[email protected]
+32 2 627.41.37