Archiv des Autors: s.buchholz

New paper on urban pollinators

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.

Two faunistic papers on grassland invertebrates

Recently, Märkische Entomologische Nachrichten has published two faunistic papers. The first one in on Carabid beetles (Coleoptera: Carabidae) of dry grasslands in Berlin (and Brandenburg). At 52 dry grassland sites in Berlin and Brandenburg we sampled 106 species including a new record for Berlin and numerous endangered species. The second one,
Wild bees of dry grasslands in Berlin, summarises bee data from 49 dry grasslands in Berlin. Both papers highlight the importance of urban sites as secondary habitats for rare and endangered invertebrates.

New paper on urban bats

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.

New methodological paper

Assessing spider diversity in grasslands – does pitfall trap color matter? has been accepted in Journal of Arachnology.

Authors Möller M & Buchholz S

We analyzed effects of pitfall trap color (white, yellow, green, brown) on spider catches and found differences in alpha-diversity and one biological trait, namely hunting type. Attractiveness of different trap colors may arise due to differences in biological preconditions, albedo and microclimate which in turn can affect diversity and community structure of spiders. Trap color has a significant impact on spider catches and should be considered when planning surveys.

Phenotypic expressions in sand lizards

Pilot project started …

… 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.

Galápagos Research Trip 2018

Working at the Charles Darwin Research Station again

Thanks to a research fellowship sponsored by the Schimper Stiftung I was able to go to the Galápagos in February. It was great to continue my work on the Scalesia restoration project in the highlands of Santa Cruz. After intensive work in the invertebrate lab we finished all spider and beetles identifications and counted all other invertebrates caught within the long-term monitoring. This program started in 2014 and invertebrates were caught in 34 plots using pitfall and Malaise traps. First results have been recently published but more detailed analyses will be available soon.

New paper

Connectivity or area – what drives plant species richness in habitat corridors? has been accepted in Landscape Ecology.

Authors Thiele J, Kellner S, Buchholz S & Schirmel J

In a nutshell, we found out that connectivity is more important for plant species richness in linear landscape elements than area. In particular, the richness of plant species that are dispersal limited and confined to semi-natural habitats benefits from connective networks of linear landscape elements in agricultural landscapes.