Wiegand, Kerstin

[["dc.bibliographiccitation.firstpage","1038"],["dc.bibliographiccitation.issue","6"],["dc.bibliographiccitation.journal","Journal of Vegetation Science"],["dc.bibliographiccitation.lastpage","1048"],["dc.bibliographiccitation.volume","22"],["dc.contributor.author","Schleicher, Jana"],["dc.contributor.author","Meyer, Katrin M."],["dc.contributor.author","Wiegand, Kerstin"],["dc.contributor.author","Schurr, Frank M."],["dc.contributor.author","Ward, David"],["dc.date.accessioned","2017-09-07T11:44:34Z"],["dc.date.available","2017-09-07T11:44:34Z"],["dc.date.issued","2011"],["dc.description.abstract","Question: How can we disentangle facilitation and seed dispersal from environmental heterogeneity as mechanisms causing spatial associations of plant species? Location: Semi-arid savanna in the Kimberley Thorn Bushveld, South Africa. Methods: We developed a two-step protocol for the statistical differentiation of association-promoting mechanisms in plants based on the Acacia erioloba-Grewia flava association. Individuals of the savanna shrub G. flava and the tree A. erioloba were mapped on four study plots. Disentangling the mechanism causing the association of G. flava and A. erioloba involved tests of three spatial and one non-spatial null model. The spatial null models include homogeneous and heterogeneous Poisson processes for spatial randomness based on the bivariate spatial point patterns of the four plots. With the non-spatial analysis, we determined the relationship between the canopy diameter of A. erioloba trees and presence or absence of G. flava shrubs in the tree understorey to find whether shrub presence requires a minimum tree canopy diameter. Results: We first showed a significant positive spatial association of the two species. Thereafter, the non-spatial analysis supported an exclusion of environmental heterogeneity as the sole cause of this positive association. We found a minimum tree size under which no G. flava shrubs occurred. Conclusions: Our two-step analysis showed that it is unlikely that heterogeneous environmental conditions caused the spatial association of A. erioloba and G. flava. Instead, this association may have been caused by seed dispersal and/or facilitation (e.g. caused by hydraulic lift and/or nitrogen fixation by the host tree)."],["dc.identifier.doi","10.1111/j.1654-1103.2011.01310.x"],["dc.identifier.gro","3148928"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/5569"],["dc.language.iso","en"],["dc.notes.intern","Wiegand Crossref Import"],["dc.notes.status","public"],["dc.notes.submitter","chake"],["dc.relation.issn","1100-9233"],["dc.relation.orgunit","Abteilung Ökosystemmodellierung"],["dc.subject.gro","Acacia erioloba"],["dc.subject.gro","Grewia flava"],["dc.subject.gro","Plant interactions"],["dc.subject.gro","Spatial association"],["dc.subject.gro","Wiegand-Moloney O-ring statistics"],["dc.title","Disentangling facilitation and seed dispersal from environmental heterogeneity as mechanisms generating associations between savanna plants"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","153"],["dc.bibliographiccitation.journal","Geoderma"],["dc.bibliographiccitation.lastpage","162"],["dc.bibliographiccitation.volume","310"],["dc.contributor.author","Ward, David"],["dc.contributor.author","Trinogga, Juliane"],["dc.contributor.author","Wiegand, Kerstin"],["dc.contributor.author","du Toit, Justin"],["dc.contributor.author","Okubamichael, Desale"],["dc.contributor.author","Reinsch, Sabine"],["dc.contributor.author","Schleicher, Jana"],["dc.date.accessioned","2020-12-10T14:24:17Z"],["dc.date.available","2020-12-10T14:24:17Z"],["dc.date.issued","2018"],["dc.identifier.doi","10.1016/j.geoderma.2017.09.023"],["dc.identifier.issn","0016-7061"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/72206"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.relation.issn","0016-7061"],["dc.relation.orgunit","Abteilung Ökosystemmodellierung"],["dc.subject.gro","Acacia"],["dc.subject.gro","Carbon"],["dc.subject.gro","Fertility islands"],["dc.subject.gro","Legumes"],["dc.subject.gro","Nitrogen"],["dc.subject.gro","Senegalia"],["dc.subject.gro","Tarchonanthus"],["dc.subject.gro","pH"],["dc.title","Large shrubs increase soil nutrients in a semi-arid savanna"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","270"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Journal of Arid Environments"],["dc.bibliographiccitation.lastpage","278"],["dc.bibliographiccitation.volume","75"],["dc.contributor.author","Schleicher, Jana"],["dc.contributor.author","Wiegand, Kerstin"],["dc.contributor.author","Ward, David"],["dc.date.accessioned","2017-09-07T11:52:28Z"],["dc.date.available","2017-09-07T11:52:28Z"],["dc.date.issued","2010"],["dc.description.abstract","We examined the impact of shrub–shrub interactions and soil type (rocky or sandy) on growth and spatial distribution of the two savanna shrub species Tarchonanthus camphoratus and Acacia mellifera. To explore plant interactions, we compared the size of juvenile and mature T. camphoratus shrubs between different locations (under the subcanopy of A. mellifera and in the open). Juvenile T. camphoratus shrubs had similar sizes regardless of location; however, in rocky soil, mature shrubs in the open were larger than those near A. mellifera, implying an inter-specific competitive effect of A. mellifera on T. camphoratus. Juvenile T. camphoratus shrubs grew faster in the sandy than in the rocky area. Furthermore, we used the Wiegand–Moloney O-ring statistics to explore the spatial distribution of T. camphoratus. T. camphoratus showed spatial aggregation, but in the rocky area T. camphoratus juveniles were positively associated with A. mellifera (indicating facilitation as the pattern-creating process), whereas in the sandy area they were positively associated with mature T. camphoratus shrubs (indicating seed dispersal as the pattern-creating process). T. camphoratus exhibited encroachment potential in the sandy area. We showed how spatial pattern analysis can help to explore processes determining woody plant spacing and recommend its further use."],["dc.identifier.doi","10.1016/j.jaridenv.2010.10.003"],["dc.identifier.gro","3148923"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/5562"],["dc.language.iso","en"],["dc.notes.intern","Wiegand Crossref Import"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.relation.issn","0140-1963"],["dc.relation.orgunit","Abteilung Ökosystemmodellierung"],["dc.subject.gro","O-ring function"],["dc.subject.gro","Plant-plant interactions"],["dc.subject.gro","Savanna shrubs"],["dc.subject.gro","Spatial ecology"],["dc.subject.gro","Tarchonanthus camphoratus"],["dc.subject.gro","Toroidal shift"],["dc.title","Changes of woody plant interaction and spatial distribution between rocky and sandy soil areas in a semi-arid savanna, South Africa"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]