Urban ecology

We use different field methods in ecology to study wild pollinators, plant diversity, garden characteristics and climate in community gardens across Berlin and Munich.

We visit each garden about every month during the summer (April to September) with a team of interdisciplinary field scientists. In the center of each garden, we study the plants and animals within a 20 x 20 m area to ensure that the studies are comparable, even though the gardens are very different in size.

Zwei Frauen erfassen Wildbienen in einem Garten

Pollinator observation

We walk four parallel transects per garden for a total of 30 minutes. We count all insects (with focus on wild bees) on flowers or in flight and identify them as accurately as possible. Animals that cannot not be identified are caught in a net and taken to the laboratory for further identification with the help of taxonomists.

Zwei Menschen schauen in ein Beet um Pflanzen zu bestimmen

Vegetation mapping

We document all herbaceous plants, flowers and their colors in the garden in eight randomly placed 1 x 1 m quadrats within the study area. We also map all woody plants and their flowering time over the season.

Ein blaue, eine gelbe und eine weiße Schale mit Seifenwasser darin stehen in einem Garten

Pan Traps

In the week following the garden field visit, we set up three colored trays (yellow, blue, white) filled with soapy water for 48 hours. With this method, we only collect as many insects as absolutely necessary to get a standardized overview of the diversity of species that is also comparable to other ecosystems.

Frau beobachtet Pflanzen mit einem Klemmbrett in der Hand

Plant-pollinator interaction

To investigate which pollinator communities visit the flowers of different plant species, we count the flowers and observe them for five minutes at a time. We record all insects that land on the flower within this time, and analyze the insect-flower ecological interactions in relation to floral availability in the gardens.

Environmental variables

We collect various environmental variables such as air temperature and humidity, wind speed, fine dust pollution and shading by trees, as well as the management of the gardens. We have set up a weather station in each garden.

Pflanzen in Beeten und Hochbeeten im Gemeinschaftsgarten IG Feuerwache

Garden characteristics

We estimate the ground cover and note the number of different insect habitats such as deadwood structures, dry stone walls, open sandy areas or nesting boxes. We also document the number of honey bee hives.

Publications

Felderhoff, J., Gathof, A. K., Buchholz, S., Egerer, M. (2022) Vegetation complexity and nesting resource availability predict bee diversity and functional traits in community gardens. Ecological Applications, 33 (2).

in Englisch

Seitz B, Buchholz S, Kowarik I, Herrmann J, Neuerburg L., Wendler J, Winker L, Egerer M. (2022) Land sharing between cultivated and wild plants: urban gardens as hotspots for plant diversity in cities. Urban Ecosystems, 1–13.

In Englisch

Castillo Nolte, A., Buchholz, S., Pernat, N., Egerer, M. (2022) Temporal Temperature Variation in Urban Gardens Is Mediated by Local and Landscape Land Cover and Is Linked to Environmental Justice. Front. Sustain. Food Syst. 6.

in Englisch

Egerer, M. (2022) Bee discovery suggests the importance of urban gardens in a changing world. Renewable Agriculture and Food Systems. 37(5).

in Englisch