@article{DiekmannAndresBeckeretal.2019,
  author    = {Diekmann, Martin and Andres, Christian and Becker, Thomas and Bennie, Jonathan and Blueml, Volker and Bullock, James M. and Culmsee, Heike and Fanigliulo, Miriam and Hahn, Annett and Heinken, Thilo and Leuschner, Christoph and Luka, Stefanie and Meissner, Justus and M{\"u}ller, Josef and Newton, Adrian and Peppler-Lisbach, Cord and Rosenthal, Gert and van den Berg, Leon J. L. and Vergeer, Philippine and Wesche, Karsten},
  title     = {Patterns of long-term vegetation change vary between different types of semi-natural grasslands in Western and Central Europe},
  series = {Journal of vegetation science},
  volume    = {30},
  journal   = {Journal of vegetation science},
  number    = {2},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {1100-9233},
  doi       = {10.1111/jvs.12727},
  pages     = {187 -- 202},
  year      = {2019},
  abstract  = {Questions Has plant species richness in semi-natural grasslands changed over recent decades? Do the temporal trends of habitat specialists differ from those of habitat generalists? Has there been a homogenization of the grassland vegetation? Location Different regions in Germany and the UK. Methods We conducted a formal meta-analysis of re-survey vegetation studies of semi-natural grasslands. In total, 23 data sets were compiled, spanning up to 75 years between the surveys, including 13 data sets from wet grasslands, six from dry grasslands and four from other grassland types. Edaphic conditions were assessed using mean Ellenberg indicator values for soil moisture, nitrogen and pH. Changes in species richness and environmental variables were evaluated using response ratios. Results In most wet grasslands, total species richness declined over time, while habitat specialists almost completely vanished. The number of species losses increased with increasing time between the surveys and were associated with a strong decrease in soil moisture and higher soil nutrient contents. Wet grasslands in nature reserves showed no such changes or even opposite trends. In dry grasslands and other grassland types, total species richness did not consistently change, but the number or proportions of habitat specialists declined. There were also considerable changes in species composition, especially in wet grasslands that often have been converted into intensively managed, highly productive meadows or pastures. We did not find a general homogenization of the vegetation in any of the grassland types. Conclusions The results document the widespread deterioration of semi-natural grasslands, especially of those types that can easily be transformed to high production grasslands. The main causes for the loss of grassland specialists are changed management in combination with increased fertilization and nitrogen deposition. Dry grasslands are most resistant to change, but also show a long-term trend towards an increase in more mesotrophic species.},
  language  = {en}
}
@article{SchleuningTemplinHuamanetal.2011,
  author    = {Schleuning, Matthias and Templin, Mathias and Huaman, Vicky and Vadillo, Giovana P. and Becker, Thomas and Durka, Walter and Fischer, Markus and Matthies, Diethart},
  title     = {Effects of inbreeding, outbreeding, and supplemental pollen on the reproduction of a hummingbird-pollinated clonal amazonian herb},
  series = {Biotropica : a publication of the Association for Tropical Biology},
  volume    = {43},
  journal   = {Biotropica : a publication of the Association for Tropical Biology},
  number    = {2},
  publisher = {Wiley-Blackwell},
  address   = {Malden},
  issn      = {0006-3606},
  doi       = {10.1111/j.1744-7429.2010.00663.x},
  pages     = {183 -- 191},
  year      = {2011},
  abstract  = {Understory herbs are an essential part of tropical rain forests, but little is known about factors limiting their reproduction. Many of these herbs are clonal, patchily distributed, and produce large floral displays of nectar-rich 1-d flowers to attract hummingbird pollinators that may transport pollen over long distances. The aim of this study was to investigate the effects of clonality, cross-proximity, and patchy distribution on the reproduction of the hummingbird-pollinated Amazonian herb Heliconia metallica. We experimentally pollinated flowers within populations with self-pollen and with pollen of different diversity, crossed flowers between populations, and added supplemental pollen to ramets growing solitarily or in conspecific patches. Only flowers pollinated early in the morning produced seeds. Selfed flowers produced seeds, but seed number and mass were strongly reduced, suggesting partial sterility and inbreeding depression after selfing. Because of pollen competition, flowers produced more seeds after crosses with several than with single donor plants. Crosses between populations mostly resulted in lower seed production than those within populations, suggesting outbreeding depression. Ramets in patches produced fewer seeds than solitary ramets and were more pollen-limited, possibly due to geitonogamy and biparental inbreeding in patches. We conclude that high rates of geitonogamy due to clonality and pollen limitation due to the short receptivity of flowers and patchy distribution constrain the reproduction of this clonal herb. Even in unfragmented rain forests with highly mobile pollinators, outbreeding depression may be a widespread phenomenon in plant reproduction.},
  language  = {en}
}