When Has an Abandoned Field Become a Semi-Natural Grassland or Heathland?

This study deals with the succession from abandoned fields to semi-natural grassland and heathland vegetation and the discrimination between these types of habitat. We hypothesise that semi-natural condition may be indicated by species lists of vascular plants. A statistical classification model is developed, based on 2059 reference samples from Danish ancient grasslands and heathlands, and abandoned fields of varying age. This Succession Model is shown to discriminate effectively between abandoned fields and semi-natural habitats, and it is suggested to be useful for the detection of conservation-worthy abandoned fields. A test of four hypotheses regarding the model prediction of naturalness of abandoned fields revealed that successional age, period of abandonment and successional trajectory had significant impact on the succession on abandoned fields. The implications of the results for restoration of semi-natural habitats and the usefulness of the model in practical conservation management are discussed

Discrimination of semi-natural plant communities from abandoned fields by ordination and neural networks

This study deals with the succession from abandoned fields to semi-natural grassland and heathland vegetation and the discrimination between these types of habitat. We hypothesise that semi-natural condition may be indicated by species lists of vascular plants. A statistical classification model is developed, based on 2059 reference samples from Danish ancient grasslands and heathlands, and abandoned fields of varying age. This Succession Model is shown to discriminate effectively between abandoned fields and semi-natural habitats, and it is suggested to be useful for the detection of conservation-worthy abandoned fields. A test of four hypotheses regarding the model prediction of naturalness of abandoned fields revealed that successional age, period of abandonment and successional trajectory had significant impact on the succession on abandoned fields. The implications of the results for restoration of semi-natural habitats and the usefulness of the model in practical conservation management are discussed

Taxonomy and phylogeny of the genus <i>Steinera </i>(Arctomiales, Arctomiaceae) in the subantarctic Islands of Crozet and Kerguelen

International audienceThe lichenized genus Steinera is revised for the archipelagos of Crozet and of Kerguelen, with a high level of endemism revealed. It is shown to represent a good example of convergent evolution between two different orders. Phylogenetic analyses using nuLSU, RPB1 and mtSSU sequences show that two different species groups can be recognized: Steinera s. str. belongs to the Arctomiaceae (Arctomiales) and is characterized notably by species having pluriseptate ascospores, and a second species group belongs to the Koerberiaceae (Peltigerales) and is characterized notably by simple ascospores sometimes having a plasma-bridge. The genus Henssenia is newly described to accommodate this latter group. The type species of Steinera is shown to have been erroneously treated in the past, with Steinera molybdoplaca being the type of Steinera and "S." glaucella belonging to the genus Henssenia. A sorediate morph is recorded for S. molybdoplaca and the results confirmed using a 4-gene phylogeny, including nuITS sequences. Some species previously described in the genera Arctomia and Massalongia from the Southern Hemisphere are shown to belong to Steinera s. str. Five new species are described: Steinera isidiata Ertz and R.S. Poulsen, S. membranacea Ertz and R. S. Poulsen, S. lebouvieri Ertz, S. pannarioides Ertz and R. S. Poulsen and Henssenia subglaucella Ertz and R. S. Poulsen along with seven new combinations: Steinera intricata (Ovstedal) Ertz, S. latispora (Ovstedal) Ertz, S. olechiana (Alstrup and Sochting) Ertz and Sochting, S. subantarctica (Ovstedal) Ertz, Henssenia glaucella (Tuck.) Ertz, R. S. Poulsen and Sochting, H. radiata (P. James and Henssen) Ertz and H. werthii (Zahlbr.) Ertz, R. S. Poulsen and Sochting. An epitype is chosen for Henssenia glaucella and a neotype for H. werthii. "Steinera" symptychia has an isolated phylogenetic position in the Koerberiaceae and might represent a distinct, new genus. World-wide identification keys to the species of Henssenia and Steinera are provided

Ducatina umbilicata gen. et sp. nov., a remarkable Trapeliaceae from the subantarctic islands in the Indian Ocean

International audienceThe new genus and species Ducatina umbilicata is described from Îles Crozet and Îles Kerguelen. This lichen is characterized by an umbilicate thallus with a black verrucose lower surface and a greyish to dark olivaceous smooth upper surface having large verrucae, large semi-immersed cephalodia, semi-immersed apothecia with a prominent thalline margin, simple, mainly ellipsoid ascospores of 23–42×12–25 µm and the presence of unknown chemical compounds. Phylogenetic analyses using nuLSU and mtSSU sequences place Ducatina in the Trapeliaceae (Baeomycetales). The new taxon is closely related to Orceolina antarctica and O. kerguelensis, two other lichens endemic to these subantarctic islands, differing by its morphology and the lack of chemical compounds. Ducatina is the only genus in the Trapeliaceae to develop a large umbilicate thallus