According to data from Eurostat and the OECD, currently 17% of the land surface in Europe is urban areas that are home to 75% of the population. Beyond the effects of urbanization on climate change, imbalances occurred in terrestrial life, including the smallest invertebrates.
With this premise, researchers from Austria began investigating how urban ecosystems are changing biodiversity, and in this case, arthropods on which the success of other species, such as birds, located several steps higher in the trophic chain, depends. The results of their research were published in the journal Boundaries in Ecology and Evolution.
Thus, arthropod specimens were collected at 180 sites in an urban mosaic in Innsbruck, Austria, and at each point the insects were collected in three micro-habitats: treetop, bark, and shrub layer. Considering the level of urbanization in the radius of 100, 500 and 1,000 meters around the sampling points, Abundance (how many arthropods), richness (how many different species) and diversity (all species) were analyzed.
Safe in the bark of trees
The investigation concluded that Urbanization negatively affects both the richness and diversity of arthropods in both the tree cover and the undergrowth.It often replaces flightless species, especially in flightless species such as web spiders and bowtails.
As for the bark of trees, neither richness nor diversity changed as the level of urbanization increased.. The researchers explain this fact by saying that it is the part of the tree that is less exposed to the sun’s rays and is also a good shelter against the urban ‘heat island’ effect.
The study also makes a point particularly abundance of bark lice and crab spiders in thickets, more concentrated in more settled areas. “Bushes in urban areas can be more productive, produce more nutritious leaves, and support more herbivores in areas with more tree cover, usually compared to light-limited substrate,” says the newspaper. Other groups detected in larger amounts were aphids, mealybugs and flies.
Some species regress and others develop
“This result strongly suggests that: While urbanization negatively affects flightless arthropods, flying insects succeed in colonizing and developing in urban areas.. Habitat fragmentation in urban areas is undoubtedly the main driver of this filtering pattern, as species with low dispersal abilities (here they have no wings) are hardly able to colonize such habitats,” he continues.
Researchers come to the conclusion that This change in the availability of arthropods, which are key prey in the food chain for species at higher trophic levelsIt may mean a change in the foraging behavior of birds with direct consequences on their nutritional status, which may force them to change their diet or increase their search efforts.
Reference work: https://www.frontiersin.org/articles/10.3389/fevo.2023.980387/full#h6
……
Contact address of the environment department: [email protected]