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.
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.
Scalesia pedunculata – an endemic tree in the Galápagos
Argiope spec. – a spider species commonly found in Scalesia trees
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.
Together with my colleagues from the invertebrate lab of the Charles Darwin Research Station I recently finished the identifications of the spider, beetle and bug samples from the Los Gemelos project. We found a number of very interesting endemic species such as the spiders Darwinneon crypticus, Galaporella thaleri or Olios galapagoensis as well as endemic beetles such as Anchonus galapagoensis, Ataenius aequatorialis or Mordellistena galapagoensis. It was a great experience for me to see all this new species – and of course to work with the awesome team. Many thanks! Back in Berlin again, I am going to run the statistical analyses – look out for coming publications. If you are already interested in some basic results from the Los Gemelos project please make a note of the following paper which will published in the Galápagos Report soon:
Restoration of the blackberry-invaded Scalesia forest: impacts on the vegetation, invertebrates and birds(by Jäger H, Cimadom A, Buchholz S, Tebbich S, Rodriguez J, Barrera D, Breuer M, Walentowitz A, Carrión A, Sevilla C & Causton C)
I had a very amazing field trip to the Scalesia forests at Los Gemelos. Scalesia species have been called „the Darwin’s finches of the plant world“ because they show a similarly dramatic pattern of adaptive radiation. These giant daisy trees have an entire vegetation zone named after them. Scalesia is a genus of the family Asteraceae that is endemic to the Galapagos Islands. They consist of 15 native shrubs and tree species with six subspecies and each of the species has adapted to the different vegetation zones across the different islands.
Scalesia forests at Los Gemelos (Santa Cruz, Galápagos)
Study site at Los Gemelos. Scalesia forest with blackberry control
A zone in the highlands of some islands is referred to as the Scalesia Zone which is a lush cloud forest and home to the largest of the Scalesia species (S. pedunculata dominant on Santa Cruz). From a distance the vegetation looks like a hummocky bog land but under the canopy, mosses, bromeliads, epiphytes and orchids thrive. The whole Scalesia zone is most threatened by human settlement. The zone is some of the most fertile land area on the Islands and perfect for agriculture. This has led to much of the original Scalesia forest being chopped down and replaced. Furthermore, the spread of introduced species such as blackberry has adverse effects on the habitat.
Malaise trap at Los Gemelos
Here is a very interesting article about Scalesia forests which was published in GALAPAGOS REPORT 2009 -2010.