Meyer, Katrin Mareike

[["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","355"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Acta Oecologica"],["dc.bibliographiccitation.lastpage","364"],["dc.bibliographiccitation.volume","33"],["dc.contributor.author","Moustakas, Aristides"],["dc.contributor.author","Wiegand, Kerstin"],["dc.contributor.author","Getzin, Stephan"],["dc.contributor.author","Ward, David"],["dc.contributor.author","Meyer, Katrin M."],["dc.contributor.author","Guenther, Matthias"],["dc.contributor.author","Mueller, Karl-Heinz"],["dc.date.accessioned","2017-09-07T11:52:23Z"],["dc.date.available","2017-09-07T11:52:23Z"],["dc.date.issued","2008"],["dc.description.abstract","Nearest tree neighbour distances and the tree spatial formation on a large scale over time and space replicates were examined. The study was conducted in a natural savanna ecosystem in the Southern Kalahari, South Africa. Nearest tree neighbour and point pattern analysis methods were used to investigate changes in the spatial pattern of trees in two plots. Trees larger than 2 m canopy diameter were mapped. We used aerial photographs of the study area from 1940, 1964, 1984, 1993, and a satellite image from 2001 to follow two plots over time. Field work was carried out too for classification accuracy. We were able to identify and individually follow over 2400 individual trees from 1940 until 2001. Nearest neighbour analysis results indicate that dead trees were on average closer to their nearest neighbouring trees than living trees were to their neighbours. Most dead trees were on average 6 m from their nearest neighbours, while most living trees were about 20 m apart. Point pattern analysis results show a cyclical transition from clumped to random and sequentially to regular tree spacing. These transitions were not correlated across two plots. Generally, decreases in small-scale clumping coincided with periods of high mortality. Our findings show that regular, clumped, and random tree pattern can occur, pending on time, location, and scale within the location."],["dc.identifier.doi","10.1016/j.actao.2008.01.008"],["dc.identifier.gro","3148903"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/5540"],["dc.language.iso","en"],["dc.notes.intern","Wiegand Crossref Import"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.relation.issn","1146-609X"],["dc.relation.orgunit","Abteilung Ökosystemmodellierung"],["dc.subject.gro","Acacia erioloba"],["dc.subject.gro","Long-term study"],["dc.subject.gro","Nearest neighbour analysis"],["dc.subject.gro","Point pattern analysis"],["dc.subject.gro","Savanna"],["dc.subject.gro","Spatial patterns"],["dc.subject.gro","Tree mortality"],["dc.subject.gro","Tree size"],["dc.subject.gro","Tree-tree competition"],["dc.title","Spacing patterns of an Acacia tree in the Kalahari over a 61-year period: How clumped becomes regular and vice versa"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]