@article{NaafWulf2012,
  author    = {Naaf, Tobias and Wulf, Monika},
  title     = {Does taxonomic homogenization imply functional homogenization in temperate forest herb layer communities?},
  series = {Plant ecology : an international journal},
  volume    = {213},
  journal   = {Plant ecology : an international journal},
  number    = {3},
  publisher = {Springer},
  address   = {Dordrecht},
  issn      = {1385-0237},
  doi       = {10.1007/s11258-011-9990-3},
  pages     = {431 -- 443},
  year      = {2012},
  abstract  = {Biotic homogenization, the decrease in beta diversity among formerly distinct species assemblages, has been recognized as an important form of biotic impoverishment for more than a decade. Although researchers have stressed the importance of the functional dimension to understand its potential ecological consequences, biotic homogenization has mostly been studied at a taxonomic level. Here, we explore the relationship between taxonomic and functional homogenization using data on temperate forest herb layer communities in NW Germany, for which taxonomic homogenization has recently been demonstrated. We quantified beta diversity by partitioning Rao's quadratic entropy. We found a general positive relationship between changes in taxonomic and functional beta diversity. This relationship was stronger if multiple functional traits were taken into account. Averaged across sites, however, taxonomic homogenization was not consistently accompanied by functional homogenization. Depending on the traits considered, taxonomic homogenization occurred also together with functional differentiation or no change in functional beta diversity. The species shifts responsible for changes in beta diversity differed substantially between taxonomic and functional beta diversity measures and also among functional beta diversity measures based on different traits. We discuss likely environmental drivers for species shifts. Our study demonstrates that functional homogenization must be explicitly studied as an independent phenomenon that cannot be inferred from taxonomic homogenization.},
  language  = {en}
}
@article{KolkNaafWulf2017,
  author    = {Kolk, Jens and Naaf, Tobias and Wulf, Monika},
  title     = {Paying the colonization credit},
  series = {Biodiversity and conservation},
  volume    = {26},
  journal   = {Biodiversity and conservation},
  publisher = {Springer},
  address   = {Dordrecht},
  issn      = {0960-3115},
  doi       = {10.1007/s10531-016-1271-y},
  pages     = {735 -- 755},
  year      = {2017},
  abstract  = {Massive historical land cover changes in the Central European lowlands have resulted in a forest distribution that now comprises small remnants of ancient forests and more recently established post-agricultural forests. Here, land-use history is considered a key driver of recent herb-layer community changes, where an extinction debt in ancient forest remnants and/or a colonization credit in post-agricultural forests are being paid over time. On a regional scale, these payments should in theory lead toward a convergence in species richness between ancient and post-agricultural forests over time. In this study, we tested this assumption with a resurvey of 117 semi-permanent plots in the well-studied deciduous forests of the Prignitz region (Brandenburg, NE Germany), where we knew that the plant communities of post-agricultural stands exhibit a colonization credit while the extinction debt in ancient stands has largely been paid. We compared changes in the species richness of all herb layer species, forest specialists and ancient forest indicator species between ancient and post-agricultural stands with linear mixed effect models and determined the influence of patch connectivity on the magnitude of species richness changes. Species richness increased overall, but the richness of forest specialists increased significantly more in post-agricultural stands and was positively influenced by higher patch connectivity, indicating a convergence in species richness between the ancient and postagricultural stands. Furthermore, the richness of ancient forest indicator species only increased significantly in post-agricultural stands. For the first time, we were able to verify a gradual payment of the colonization credit in post-agricultural forest stands using a comparison of actual changes in temporal species richness.},
  language  = {en}
}