„Urbanisation modulates plant-pollinator interactions in invasive vs. native plant species“ has been published in Scientific Reports. The article is open access.
In this article, we show that invasive black locust (Robinia pseudoacacia) is a “pollinator-friendly” tree and attracts not only honey bees but also wild bees and other wild pollinators. However, we also found that attractiveness of black locust decreases with increasing urbanisation.
Tree cover mediates the effect of ALAN on urban bats has been published in Frontiers in Ecology and Evolution. For Download, please go to the Frontiers Webpage.
Abstract: With urban areas growing worldwide, so does artificial light at night (ALAN) which negatively affects many nocturnal animals, including bats. The response of bats to ALAN ranges from some opportunistic species taking advantage of insect aggregations around street lamps, particularly those emitting ultraviolet (UV) light, to others avoiding lit areas at all. Tree cover has been suggested to mitigate the negative effects of ALAN on bats by shielding areas against light scatter. Here, we investigated the effect of tree cover on the relationship between ALAN and bats in Berlin, Germany. In particular, we asked if this interaction varies with the UV light spectrum of street lamps and also across urban bat species. We expected trees next to street lamps to block ALAN, making the adjacent habitat more suitable for all species, irrespective of the wavelength spectrum of the light source. Additionally, we expected UV emitting lights next to trees to attract insects and thus, opportunistic bats. In summer 2017, we recorded bat activity at 22 green open spaces in Berlin using automated ultrasonic detectors. We analyzed bat activity patterns and landscape variables (number of street lamps with and without UV light emission, an estimate of light pollution, and tree cover density around each recording site within different spatial scales) using generalized linear mixed-effects models with a negative binomial distribution. We found a species-specific response of bats to street lamps with and without UV light, providing a more detailed picture of ALAN impacts than simply total light radiance. Moreover, we found that dense tree cover dampened the negative effect of street lamps without UV for open-space foraging bats of the genera Nyctalus, Eptesicus, and Vespertilio, yet it amplified the already existing negative or positive effect of street lamps with or without UV on Pipistrellus pipistrellus, P. pygmaeus, and Myotis spp. Our study underpins the importance of minimizing artificial light at night close to vegetation, particularly for bats adapted to spatial complexity in the environment (i.e., clutter-adapted species), and to increase dense vegetation in urban landscape to provide, besides roosting opportunities, protection against ALAN for open-space foraging bats in city landscapes.
… with Johannes Müller from Museum für Naturkunde Berlin on urban ecology and phenotypic expressions in different Berlin populations of the sand lizard Lacerta agilis, including field 3D photogrammetry. In particular, we are keen to detect possible intra-specific trait variations in sand lizard populations along rural-urban gradients.
My last post belongs to the past by now – anyway, that means that I moved to my outdoor workplace. We are mapping sand lizard populations and sampling pollinators, moths (and recording bats at the same time) and still ground-dwelling arthropods. We also running an experiments to measure seed predation along urban gradients. Hopefully we are able to start another experiment on pollinator visitation rates soon – so long as the weather is co-operating.
Plants, plant traits and ground-dwelling arthropods
Unfortunately, spring was very cold and rainy but however, we ‚bravely‘ started our field work for the BIBS project some weeks ago. Currently, our team is doing the plant diversity assessments and also pitfall traps are exposed. Moreover, we are measuring plant traits to analyse intraspecific trait variations along the urbanisation gradient – we are going to run these analyses for invertebrate taxa and hopefully sand lizard populations as well – wait and see. In addition, some students are observing phenology of plant species at 30 sites – very labour-intensive. Today I emptied our pitfall traps for the first time and I can’t wait to study our samples in the lab.
Urban dry grassland along the highway.
Urban dry grassland along the Heerstraße.
Rural and old grasslands in the Park Klein-Glienicke.
The German Society of general and applied Entomology (DGaaE) and the German Scientific Society for Plant Protection and Plant Health (DPG) organised a conference on insect diversity in cities (III. Urbane Pflanzen Conferenz). I contributed a talk on habitat function of urban meadows for wild bees with emphasis on urbanisation effects (see Abstract in German). Due to a very diverse audience with many relevant stakeholders and decision-makers (e.g. scientists, gardeners, landscape planners, landscape architects, authorities and NGOs) it was possible to elaborate this topic from different perspectives. At the end we had very interesting – sometimes controverse – discussions to develop recommendations how to make cities more insect friendly and to comment on the new white book „Grün in der Stadt“ which was recently send out for preview. The official presentation of the white book will be in May 2017.
Disentangling urban habitat and matrix effects on wild bee specieshas been published in PeerJ.
Authors Fischer LK, Eichfeld J, Kowarik I & Buchholz S
Abstract In face of a dramatic decline of wild bee species in many rural landscapes, potential conservation functions of urban areas gain importance. Yet effects of urbanization on pollinators, and in particular on wild bees, remain ambiguous and not comprehensively understood. This is especially true for amenity grassland and extensively managed wastelands within large-scale residential housing areas. Using Berlin as study region, we aimed to investigate (a) if these greenspaces are accepted by wild bee assemblages as foraging habitats; (b) how assemblage structure of bees and individual bee species are affected by different habitat (e.g., management, flower density) and urban matrix variables (e.g., isolation, urbanization); and (c) to what extend grassland restoration can promote bees in urban environments. In summer 2012, we collected 62 bee species belonging to more than 20 % of the taxa known for Berlin. Urbanization significantly affected species composition of bees; 18 species were affiliated to different levels of urbanization. Most bee species were not affected by any of the environmental variables tested, and urbanization had a negative effect only for one bee species. Further, we determined that restoration of diverse grasslands positively affected bee species richnesss in urban environments. We conclude that differently structured and managed greenspaces in large-scale housing areas can provide additional foraging habitats and refuges for pollinators. This supports approaches towards a biodiversity friendly management within urban regions and may be of particular importance given that anthropogenic pressure is increasing in many rural landscapes.
Several raptor species become more and more urban dwellers and they thrive very well in many different urban habitats now. In Berlin, four species are very common – even in heavily urbanised areas. While the common buzzard (Buteo buteo) mostly inhabits parks and urban woodlands, aeries of the peregrine falcon (Falco peregrinus) and the common kestrel (Falco tinnunculus) can be found in higher buildings all over the city. The latter can be regularly seen at the Tempelhofer Feld (see photo) and a good place to observe the peregrine falcon is the Alexanderplatz and the television tower which is used as raised hide, even during the night.
In the last years, we conducted research on the northern goshawk (Accipiter gentilis). Interestingly, this species spreads more and more into the heavily urbanised areas and while it was breeding in urban parks and large gardens at the beginning, aeries can be found in backyards in isolated tree by now. Sometimes northern goshawks are even hunting in busy roads like the Schlesische Straße in Kreuzberg. Watch out for more findings …