@article{DannerKellerHaerteletal.2017,
  author    = {Danner, Nadja and Keller, Alexander and H{\"a}rtel, Stephan and Steffan-Dewenter, Ingolf},
  title     = {Honey bee foraging ecology: Season but not landscape diversity shapes the amount and diversity of collected pollen},
  series = {PLoS ONE},
  volume    = {12},
  journal   = {PLoS ONE},
  number    = {8},
  doi       = {10.1371/journal.pone.0183716},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170424},
  pages     = {e0183716},
  year      = {2017},
  abstract  = {The availability of pollen in agricultural landscapes is essential for the successful growth and reproduction of honey bee colonies (Apis mellifera L.). The quantity and diversity of collected pollen can influence the growth and health of honey bee colonies, but little is known about the influence of landscape structure on pollen diet. In a field experiment, we rotated 16 honey bee colonies across 16 agricultural landscapes, used traps to collect samples of collected pollen and observed intra-colonial dance communication to gain information about foraging distances. DNA metabarcoding was applied to analyze mixed pollen samples. Neither the amount of collected pollen nor pollen diversity was related to landscape diversity. However, we found a strong seasonal variation in the amount and diversity of collected pollen in all sites independent of landscape diversity. The observed increase in foraging distances with decreasing landscape diversity suggests that honey bees compensated for lower landscape diversity by increasing their pollen foraging range in order to maintain pollen amount and diversity. Our results underscore the importance of a diverse pollen diet for honey bee colonies. Agri-environmental schemes aiming to support pollinators should focus on possible spatial and temporal gaps in pollen availability and diversity in agricultural landscapes.},
  language  = {en}
}
@article{TooKellerSickeletal.2018,
  author    = {Too, Chin Chin and Keller, Alexander and Sickel, Wiebke and Lee, Sui Mae and Yule, Catherine M.},
  title     = {Microbial Community Structure in a Malaysian Tropical Peat Swamp Forest: The Influence of Tree Species and Depth},
  series = {Frontiers in Microbiology},
  volume    = {9},
  journal   = {Frontiers in Microbiology},
  doi       = {10.3389/fmicb.2018.02859},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229000},
  year      = {2018},
  abstract  = {Tropical peat swamp forests sequester globally significant stores of carbon in deep layers of waterlogged, anoxic, acidic and nutrient-depleted peat. The roles of microbes in supporting these forests through the formation of peat, carbon sequestration and nutrient cycling are virtually unknown. This study investigated physicochemical peat properties and microbial diversity between three dominant tree species: Shorea uliginosa (Dipterocarpaceae), Koompassia malaccensis (legumes associated with nitrogen-fixing bacteria), Eleiodoxa conferta (palm) and depths (surface, 45 and 90 cm) using microbial 16S rRNA gene amplicon sequencing. Water pH, oxygen, nitrogen, phosphorus, total phenolic contents and C/N ratio differed significantly between depths, but not tree species. Depth also strongly influenced microbial diversity and composition, while both depth and tree species exhibited significant impact on the archaeal communities. Microbial diversity was highest at the surface, where fresh leaf litter accumulates, and nutrient supply is guaranteed. Nitrogen was the core parameter correlating to microbial communities, but the interactive effects from various environmental variables displayed significant correlation to relative abundance of major microbial groups. Proteobacteria was the dominant phylum and the most abundant genus, Rhodoplanes, might be involved in nitrogen fixation. The most abundant methanogens and methanotrophs affiliated, respectively, to families Methanomassiliicoccaceae and Methylocystaceae. Our results demonstrated diverse microbial communities and provide valuable insights on microbial ecology in these extreme ecosystems.},
  language  = {en}
}