3.5.2012: Forschung CH

Lebensraum Schrebergarten

Le jardin familial comme habitat


Pellkofer Sarah

Im Rahmen einer Masterarbeit an der Universität Zürich wurde analysiert, welche Faktoren die Anwesenheit und Diversität von Wildbienen und Wespen in Schrebergärten in der Stadt Zürich beeinflussen. Dabei wurden Eigenschaften von Schrebergärten auf lokaler wie auch auf Landschaftsebene betrachtet.

Dans le cadre d’un travail de master à l’Université de Zurich, les facteurs influençant la présence et la diversité des abeilles et guêpes sauvages dans les jardins familiaux zurichois ont été analysés. Les caractéristiques des jardins familiaux au niveau local comme au niveau paysager y ont été pris en compte.


Urbanization has been increasingly transforming natural areas into city landscapes dominated by man-made infrastructure. Family gardens (Areas) are one component of this urban landscape that could act as essential habitat to species of solitary-nesting Hymenoptera that still remain within the city, however, many of these gardens have been facing increased pressure to be closed and developed. As the ecosystem services of pollination and pest control that these Hymenoptera provide are extremely valuable to humans, this study sought to determine if these gardens are truly a habitat for solitary-nesting Hymenoptera within the city of Zurich and also what features of these gardens on the local and landscape scale make them more suitable as such a habitat. Using trap-nests this study analyzed how strongly a) abundance, b) richness and c) evenness were predicted by three landscape-level variables and three local-level variables. The landscape-level variables examined were 1) Area size, 2) the greenness of the Area surroundings and 3) the Area’s daily potential solar radiation and the local-level variables were 4) the use of pesticides, 5) the number of existing nesting sites, and 6) the ground cover diversity within individually managed garden plots in each Area. The results of this study showed that on the landscape-level Areas that were smaller with greener surroundings had increased abundance and richness of hymenopteran genera. Areas that were smaller also had increased evenness among those genera. Daily potential solar radiation was not an effective predictor of the abundance, richness and evenness of solitary-nesting Hymenoptera. On the local-level, garden plots with lower ground cover diversity had a higher abundance of hymenopteran genera; however, it was not a predictor the richness and evenness of the genera. Furthermore, the number of existing nesting sites and the use of pesticides were not effective predictors of the abundance, richness and evenness of solitary-nesting Hymenoptera. Although the findings of this study were not in line with many of the original hypotheses, the larger finding that there are a great number of hymenopteran individuals and moreover a wide variety of genera utilizing these family gardens within all varieties of gardens analyzed, it can be said that these family gardens are an important habitat for these species. Therefore, the value of the ecosystem services provided by the species utilizing these gardens should be taken into account when determining the best future use for the urban land currently occupied by family gardens in the city of Zurich.

Keywords:
Biodiversität, Wildbienen, Wespen, Gärten, Stadtökologie

Art der Publikation:
Masterarbeit

Literatur:
Pellkofer S. (2012). The effects of local and landscape-level characteristics on the abundance and diversity of solitary-nesting Hymenoptera in urban family gardens. Masterarbeit, Universität Zürich.
http://www.ieu.uzh.ch/research/ecology/community/bees.html

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Kontaktadresse:
Sarah Pellkofer
Institut für Evolutionsbiologie und Umweltwissenschaften
Universität Zürich
Winterthurerstrasse 190
CH-8057 Zürich

sarah.pellkofer@ieu.uzh.ch
Tel: +41 (0)44 635 61 19


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