Wiegand, Kerstin

[["dc.bibliographiccitation.firstpage","149"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Journal of Ecology"],["dc.bibliographiccitation.lastpage","160"],["dc.bibliographiccitation.volume","101"],["dc.contributor.author","Punchi-Manage, Ruwan"],["dc.contributor.author","Getzin, Stephan"],["dc.contributor.author","Wiegand, Thorsten"],["dc.contributor.author","Kanagaraj, Rajapandian"],["dc.contributor.author","Savitri Gunatilleke, C. V."],["dc.contributor.author","Nimal Gunatilleke, I. A. U."],["dc.contributor.author","Wiegand, Kerstin"],["dc.contributor.author","Huth, Andreas"],["dc.date.accessioned","2017-09-07T11:52:22Z"],["dc.date.available","2017-09-07T11:52:22Z"],["dc.date.issued","2013"],["dc.description.abstract","One of the primary goals in community ecology is to determine the relative importance of processes and mechanisms that control biodiversity. Here, we examined habitat-driven species assemblages and species distribution patterns as well as their temporal variations for three life stages of two censuses of a 25-ha mixed dipterocarp forest at Sinharaja (Sri Lanka). Our general objective was to find out whether the species assemblages and associated habitat types changed with life stage, spatial scale and species attributes. We also analyse whether the habitat types were related to certain indicator species. Habitat types were determined with multivariate regression tree analyses driven by topographic variables. We found species assemblages associated with five distinct habitat types that appeared consistently for all life stages of the two censuses. These habitats were related to ridge-valley gradients and a pronounced contrast in south-west versus north-east aspect. Habitat-driven structuring was weak at the recruit stage but strong in the juvenile and adult stages. The species assemblage variance explained by topographic variables for different life stages ranged between 10{\\%} for recruits and 23{\\%} for juveniles. The species assemblages determined for different spatial scales (10, 20, 50 m) showed similar habitat partitioning, but the variance explained by the topographic variables increased in all life stages with spatial scale. This could be due to the homogenizing effect of topographic variables at the larger scales and unaccounted environmental variation at the smaller scales. The number of indicator species identified in the two censuses was higher in the juvenile stage than in the adult stage, and nearly all indicator species in the adult stage were also indicator species in the juvenile stage. Synthesis. Our study showed that approximately 75{\\%} of the variance in local species composition is unexplained. This may be due to spatially structured processes such as dispersal limitation, unaccounted biotic and abiotic environmental variables, and stochastic effects, but only 25{\\%} were due to topographic habitat association. Although the pronounced ridge-valley gradient and contrast of south-west versus north-east aspect created consistent habitats, our results suggest that local species assemblages at Sinharaja forest are jointly shaped by neutral and niche processes."],["dc.identifier.doi","10.1111/1365-2745.12017"],["dc.identifier.gro","3148900"],["dc.identifier.pmid","24669731"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/5537"],["dc.language.iso","en"],["dc.notes.intern","Wiegand Crossref Import"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.relation.issn","0022-0477"],["dc.relation.orgunit","Abteilung Ökosystemmodellierung"],["dc.subject.gro","Determinants of plant community diversity and stru"],["dc.subject.gro","Dispersal limitation"],["dc.subject.gro","Habitat association"],["dc.subject.gro","Indicator species"],["dc.subject.gro","Multivariate regression tree"],["dc.subject.gro","Neutral theory"],["dc.subject.gro","Sinharaja forest"],["dc.subject.gro","Spatial scale"],["dc.subject.gro","Topography"],["dc.title","Effects of topography on structuring local species assemblages in a Sri Lankan mixed dipterocarp forest"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","376"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Ecology"],["dc.bibliographiccitation.lastpage","386"],["dc.bibliographiccitation.volume","95"],["dc.contributor.author","Punchi-Manage, Ruwan"],["dc.contributor.author","Wiegand, Thorsten"],["dc.contributor.author","Wiegand, Kerstin"],["dc.contributor.author","Getzin, Stephan"],["dc.contributor.author","Gunatilleke, C. V. Savitri"],["dc.contributor.author","Gunatilleke, I. A. U. Nimal"],["dc.date.accessioned","2017-09-07T11:52:23Z"],["dc.date.available","2017-09-07T11:52:23Z"],["dc.date.issued","2014"],["dc.description.abstract","Niche and neutral theories emphasize different processes that contribute to the maintenance of species diversity and should leave different spatial structures in species assemblages. In this study we used variation partitioning in combination with distance‐based Moran's eigenvector maps and habitat variables to determine the relative importance of the effects of pure habitat, pure spatial, and spatially structured habitat processes on the spatial distribution of tree species composition and richness in a 25‐ha tropical rain forest of Sinharaja/Sri Lanka. We analyzed the contribution of those components at three spatial scales (10 m, 20 m, and 50 m) for all trees and the three life stages: recruits, juveniles, and adults. At the 10‐m scale, 80% of the variation in species composition remained unexplained for recruits and adults, but only 55% for juveniles. With increasingly broader scales these figures were strongly reduced, mainly by an increasing contribution of the spatially structured habitat component, which explained 4–30%, 20–47%, and 8–35% of variation in species composition for recruits, juveniles, and adults, respectively. The pure spatial component was most important at the 20‐m scale and reached 20%, 32%, and 23% for recruits, juveniles, and adults, respectively. The spatially structured habitat component described variability at broader scales than the pure spatial component. Our results suggest that stochastic processes and spatially structuring processes of community dynamics, such as dispersal limitation and habitat association, contributed jointly to explain species composition and richness at the Sinharaja forest, but their relative importance changed with scale and life stage. Species assembly at the local scale was more strongly impacted by stochasticity, whereas the signal of habitat was stronger at the 50‐m scale where plant‐scale stochasticity is averaged out. Recent research points to an emerging consensus on the relative contribution of stochasticity, habitat, and spatial processes in governing community assembly, but how these components change with life stage, and how this is influenced by sample size, remains to be explored."],["dc.identifier.doi","10.1890/12-2102.1"],["dc.identifier.gro","3148904"],["dc.identifier.pmid","24669731"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/5541"],["dc.language.iso","en"],["dc.notes.intern","Wiegand Crossref Import"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.relation.issn","0012-9658"],["dc.relation.orgunit","Abteilung Ökosystemmodellierung"],["dc.subject.gro","Distance-based Moran's eigenvector maps"],["dc.subject.gro","Neutral theory"],["dc.subject.gro","Niche theory"],["dc.subject.gro","Sinharaja forest"],["dc.subject.gro","Spatial scale"],["dc.subject.gro","Species composition and richness"],["dc.subject.gro","Sri Lanka"],["dc.subject.gro","Variation partitioning"],["dc.title","Effect of spatial processes and topography on structuring species assemblages in a Sri Lankan dipterocarp forest"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","318"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Journal of Vegetation Science"],["dc.bibliographiccitation.lastpage","327"],["dc.bibliographiccitation.volume","27"],["dc.contributor.author","Nguyen, Hong Hai"],["dc.contributor.author","Uria-Diez, Jaime"],["dc.contributor.author","Wiegand, Kerstin"],["dc.date.accessioned","2017-09-07T11:44:38Z"],["dc.date.available","2017-09-07T11:44:38Z"],["dc.date.issued","2015"],["dc.description.abstract","Questions What are the prevailing types of intraspecific spatial distributions and interspecific association patterns at species and life stage levels of trees in a tropical rain forest? Which ecological processes could structure these patterns? Possible processes include dispersal limitation, self‐thinning, facilitation and competition between species and life stages. Location A tropical broad‐leaved forest in north‐central Vietnam. Methods We used univariate and bivariate pair‐correlation functions to investigate the spatial distribution and association patterns of 18 abundant tree species. To disentangle first‐ and second‐order effects, we used a scale separation approach with the heterogeneous Poisson process as null model. Results (1) Sixteen of 18 species had aggregated patterns at various scales and regardless of their abundance. (2) Significant and aggregated patterns were found in 64% of all specific life stages. (3) At scales up to 15 m, 12.4% species pairs showed significant associations, among that 71% were spatial attractions, 5% were spatial repulsions and 24% were non‐essential interactions. (4) In different life stage associations, attractions (81%) predominated over repulsions (19%) at small scales of up to 15 m. Conclusions Our findings provide evidence that dispersal limitation may regulate the spatial patterns of tree species. Moreover, positive spatial associations between tree species and life stages suggest the presence of species herd protection and/or facilitation in this forest stand, while the persistence of intraspecific aggregation through life stages suggests a very late onset or even absence of self‐thinning. Habitat heterogeneity plays an important role for species distribution patterns, and the spatial segregation occurs at a scale around 15 m in this forest."],["dc.identifier.doi","10.1111/jvs.12361"],["dc.identifier.gro","3148941"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/5583"],["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","Dispersal limitation"],["dc.subject.gro","Neutral theory"],["dc.subject.gro","Pair-correlation function"],["dc.subject.gro","Point pattern analysis"],["dc.subject.gro","Self-thinning"],["dc.subject.gro","Spatial pattern"],["dc.subject.gro","Species association"],["dc.subject.gro","Species herd protection"],["dc.subject.gro","Tropical evergreen forest"],["dc.subject.gro","Vietnam"],["dc.title","Spatial distribution and association patterns in a tropical evergreen broad-leaved forest of north-central Vietnam"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]