Preliminary Study: Climate Adaptation in Bavarian Cities - Comparative Investigation on the Use of Non-Resident and Native Urban Tree Species

The aim of this preliminary study was a comparison of the arthropod diversity of three native and closely-­related non-­resident tree species at an urban site.

In times of climate change, non-­resident tree species show a higher stress toler­ance, which in turn often leads to a higher vitality. This is the reason why they are also called ‘urban climate trees’.

At present, it is un­known how the stress tolerance of these species affects the commu­nities of inverte­brates that use the tree­tops, in­cluding herbi­vorous and plant-­suck­ing insects. The individuals in this commu­nity could be distributed relatively evenly among the exis­ting species; however, certain species could also be­come domi­nant, repro­duce massively and damage the tree or impair its function as a city tree. 

The study at hand thus aimed at comparing urban climate trees and native trees regarding their vulner­­ability to pest infes­tation. This includes the character­ization of the canopy commu­nities. These data also allowed analysis of the extent to which non-­resident city trees contribute to sus­taining bio­diverse tree canopies.

Fieldwork of this study was carried out within the frame­work of a master thesis in biology over one grow­ing season based on a screen­ing of the  bio­diversity of insect and arachnid species on native and non-­resident trees species of the climate change project „Urban Green 2021“ (funded by StMELF) in Wuerz­burg. Due to urban heat island (UHI) effects being intensi­fied by climate change, pre­dominately non-­resident trees will be planted in the future at urban street sites.

This pre­liminary study is a start to establish a reliable database for a compara­tive evaluation of the bio­diversity of canopy inhabiting arthro­pods of native and non-­resident trees species. The results are meant to be used, for example, as infor­mation for environ­mental protection agencies and nature conservation asso­ciations as well as for recommen­dations to Bavarian munici­palities concer­ning the design and planning of climate tolerant green infra­structure.

The project was carried out jointly by the „Bavarian Institute for Viticulture and Horticulture” Veitshöch­heim (Dr. Susanne Böll) and the Bio­center of the Uni­versity of Wuerz­burg, Chair of Animal Ecology and Tropical Biology (Dr. Dieter Mahsberg).