Wiegand, Kerstin

[["dc.bibliographiccitation.firstpage","399"],["dc.bibliographiccitation.journal","Journal of Ecology"],["dc.bibliographiccitation.lastpage","416"],["dc.bibliographiccitation.volume","109"],["dc.contributor.author","Getzin, Stephan"],["dc.contributor.author","Erickson, Todd E."],["dc.contributor.author","Yizhaq, Hezi"],["dc.contributor.author","Muñoz‐Rojas, Miriam"],["dc.contributor.author","Huth, Andreas"],["dc.contributor.author","Wiegand, Kerstin"],["dc.date.accessioned","2020-12-08T08:09:43Z"],["dc.date.available","2020-12-08T08:09:43Z"],["dc.date.issued","2021"],["dc.description.abstract","1. So‐called fairy circles (FCs) comprise a spatially periodic gap pattern in arid grasslands of Namibia and north‐west Western Australia. This pattern has been explained with scale‐dependent ecohydrological feedbacks and the reaction‐diffusion, or Turing mechanism, used in process‐based models that are rooted in physics and pattern‐formation theory. However, a detailed ecological test of the validity of the modelled processes is still lacking. 2. Here, we test in a spinifex‐grassland ecosystem of Western Australia the presence of spatial feedbacks at multiple scales. Drone‐based multispectral analysis and spatially explicit statistics were used to test if grass vitality within five 1‐ha plots depends on the pattern of FCs that are thought to be a critical extra source of water for the surrounding matrix vegetation. We then examined if high‐ and low‐vitality grasses show scale‐dependent feedbacks being indicative of facilitation or competition. Additionally, we assessed facilitation of grass plants for different successional stages after fire at fine scales in 1‐m2 quadrats. Finally, we placed soil moisture sensors under bare soil inside the FC gap and under plants at increasing distances from the FC to test if there is evidence for the ‘infiltration feedback’ as used in theoretical modelling. 3. We found that high‐vitality grasses were systematically more strongly associated with FCs than low‐vitality grasses. High‐vitality grasses also had highly aggregated patterns at short scales being evidence of positive feedbacks while negative feedbacks occurred at larger scales. Within 1‐m2 quadrats, grass cover and mutual facilitation of plants was greater near the FC edge than further away in the matrix. Soil moisture after rainfall was lowest inside the FC with its weathered surface crust but highest under grass at the gap edge, and then declined towards the matrix, which confirms the infiltration feedback. 4. Synthesis. The study shows that FCs are a critical extra source of water for the dryland vegetation, as predicted by theoretical modelling. The grasses act as ‘ecosystem engineers’ that modify their hostile, abiotic environment, leading to vegetation self‐organization. Overall, our ecological findings highlight the validity of the scale‐dependent feedbacks that are central to explain this emergent grassland pattern via the reaction‐diffusion or Turing‐instability mechanism."],["dc.description.sponsorship","German Research Foundation ‐ DFG"],["dc.identifier.doi","10.1111/1365-2745.13493"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/69461"],["dc.language.iso","en"],["dc.notes.intern","DeepGreen Import"],["dc.relation.issn","0022-0477"],["dc.relation.issn","1365-2745"],["dc.relation.orgunit","Abteilung Ökosystemmodellierung"],["dc.rights","CC BY 4.0"],["dc.subject.gro","ecosystem engineer"],["dc.subject.gro","Normalized Difference Vegetation Index"],["dc.subject.gro","reaction-diffusion mechanism"],["dc.subject.gro","scale-dependent feedback"],["dc.subject.gro","spatial periodicity"],["dc.subject.gro","Turing dynamics"],["dc.subject.gro","unmanned aerial vehicle"],["dc.subject.gro","vegetation self-organization"],["dc.title","Bridging ecology and physics: Australian fairy circles regenerate following model assumptions on ecohydrological feedbacks"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["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","93"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Basic and Applied Ecology"],["dc.bibliographiccitation.lastpage","101"],["dc.bibliographiccitation.volume","14"],["dc.contributor.author","Jeltsch, Florian"],["dc.contributor.author","Blaum, Niels"],["dc.contributor.author","Brose, Ulrich"],["dc.contributor.author","Chipperfield, Joseph D."],["dc.contributor.author","Clough, Yann"],["dc.contributor.author","Farwig, Nina"],["dc.contributor.author","Geissler, Katja"],["dc.contributor.author","Graham, Catherine H."],["dc.contributor.author","Grimm, Volker"],["dc.contributor.author","Hickler, Thomas"],["dc.contributor.author","Huth, Andreas"],["dc.contributor.author","May, Felix"],["dc.contributor.author","Meyer, Katrin M."],["dc.contributor.author","Pagel, Jörn"],["dc.contributor.author","Reineking, Björn"],["dc.contributor.author","Rillig, Matthias C."],["dc.contributor.author","Shea, Katriona"],["dc.contributor.author","Schurr, Frank M."],["dc.contributor.author","Schröder, Boris"],["dc.contributor.author","Tielbörger, Katja"],["dc.contributor.author","Weiss, Lina"],["dc.contributor.author","Wiegand, Kerstin"],["dc.contributor.author","Wiegand, Thorsten"],["dc.contributor.author","Wirth, Christian"],["dc.contributor.author","Zurell, Damaris"],["dc.date.accessioned","2017-09-07T11:52:18Z"],["dc.date.available","2017-09-07T11:52:18Z"],["dc.date.issued","2013"],["dc.description.abstract","Improving our understanding of biodiversity and ecosystem functioning and our capacity to inform ecosystem management requires an integrated framework for functional biodiversity research (FBR). However, adequate integration among empirical approaches (monitoring and experimental) and modelling has rarely been achieved in FBR. We offer an appraisal of the issues involved and chart a course towards enhanced integration. A major element of this path is the joint orientation towards the continuous refinement of a theoretical framework for FBR that links theory testing and generalization with applied research oriented towards the conservation of biodiversity and ecosystem functioning. We further emphasize existing decision-making frameworks as suitable instruments to practically merge these different aims of FBR and bring them into application. This integrated framework requires joint research planning, and should improve communication and stimulate collaboration between modellers and empiricists, thereby overcoming existing reservations and prejudices. The implementation of this integrative research agenda for FBR requires an adaptation in most national and international funding schemes in order to accommodate such joint teams and their more complex structures and data needs. {\\textcopyright} 2013 Gesellschaft f{\\\"{u}}r {\\\"{O}}kologie."],["dc.identifier.doi","10.1016/j.baae.2013.01.001"],["dc.identifier.gro","3148895"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/5533"],["dc.language.iso","en"],["dc.notes.intern","Wiegand Crossref Import"],["dc.notes.status","public"],["dc.notes.submitter","chake"],["dc.relation.issn","1439-1791"],["dc.relation.orgunit","Abteilung Ökosystemmodellierung"],["dc.subject.gro","Biodiversity experiments"],["dc.subject.gro","Biodiversity theory"],["dc.subject.gro","Conservation management"],["dc.subject.gro","Decision-making"],["dc.subject.gro","Ecosystem functions and services"],["dc.subject.gro","Forecasting"],["dc.subject.gro","Functional traits"],["dc.subject.gro","Global change"],["dc.subject.gro","Interdisciplinarity"],["dc.subject.gro","Monitoring programmes"],["dc.title","How can we bring together empiricists and modellers in functional biodiversity research?"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.journal","Landscape Ecology"],["dc.contributor.author","Getzin, Stephan"],["dc.contributor.author","Löns, Christian"],["dc.contributor.author","Yizhaq, Hezi"],["dc.contributor.author","Erickson, Todd E."],["dc.contributor.author","Muñoz-Rojas, Miriam"],["dc.contributor.author","Huth, Andreas"],["dc.contributor.author","Wiegand, Kerstin"],["dc.date.accessioned","2021-12-01T09:22:59Z"],["dc.date.available","2021-12-01T09:22:59Z"],["dc.date.issued","2021"],["dc.description.abstract","Abstract Context Vegetation patterns in hummock grasslands of Australia’s arid interior can be very complex. Additionally, the grasslands are interspersed with variable amounts of trees and shrubs. Objectives To better understand the spatial arrangement of this vegetation structure, and in particular the unvegetated bare-soil gaps, we analyzed the scale-dependent patterns of gaps, trees, and shrubs. Methods We focused on two size categories of grassland gaps, large gaps ≥ 4 m 2 known as fairy circles (FCs) and small gaps 1 to < 4 m 2 , and on trees and shrubs. We mapped four 200 m × 200 m study plots located east of the town of Newman in Western Australia, using drone-based aerial images and LiDAR. The RGB images were converted into binary images and the gaps and woody plants were automatically segmented. The spatial patterns of the four vegetation components were analyzed, as well as the shape properties of the vegetation gaps. Results The most striking result was that small gaps appeared consistently at about 5 m distance away from the FCs, which are known as the most water-depleted locations in the grassland. The FCs were also rounder than the small gaps and this symmetry underlines their function as an extra source of water for the surrounding matrix vegetation. Trees and shrubs had spatial patterns that were unrelated to FCs, which likely results from their water uptake in deeper sub-soil layers. Conclusions The consistent distance of small gaps to FCs is further support that the Australian fairy circles are a self-organized vegetation pattern that results from ecohydrological feedbacks."],["dc.identifier.doi","10.1007/s10980-021-01358-9"],["dc.identifier.pii","1358"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/94533"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-478"],["dc.relation.eissn","1572-9761"],["dc.relation.issn","0921-2973"],["dc.relation.orgunit","Abteilung Ökosystemmodellierung"],["dc.rights","CC BY 4.0"],["dc.title","High-resolution images and drone-based LiDAR reveal striking patterns of vegetation gaps in a wooded spinifex grassland of Western Australia"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1823"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","Ecology"],["dc.bibliographiccitation.lastpage","1834"],["dc.bibliographiccitation.volume","96"],["dc.contributor.author","Punchi-Manage, Ruwan"],["dc.contributor.author","Wiegand, Thorsten"],["dc.contributor.author","Wiegand, Kerstin"],["dc.contributor.author","Getzin, Stephan"],["dc.contributor.author","Huth, Andreas"],["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","2015"],["dc.description.abstract","Interactions among neighbors influence plant performance and should create spatial patterns in local community structure. In order to assess the role of large trees in generating spatial patterns in local species richness we used the individual species-area relationship (ISAR) to evaluate the species richness of trees of different size classes (and dead trees) in neighborhoods with varying size around large trees of different focal species. To reveal signals of species interactions we compared the ISAR function of the individuals of focal species with that of randomly selected nearby locations. We expected that large trees should strongly affect the community structure of smaller trees in their neighborhood, but that these effects should fade away with increasing size class. Unexpectedly we found that only few focal species showed signals of species interactions with trees of the different size classes and that this was less likely for less abundant focal species. However, the few and relatively weak depa..."],["dc.identifier.doi","10.1890/14-1477.1"],["dc.identifier.gro","3148901"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/5538"],["dc.language.iso","en"],["dc.notes.intern","Wiegand Crossref Import"],["dc.notes.status","public"],["dc.notes.submitter","chake"],["dc.relation.issn","0012-9658"],["dc.relation.orgunit","Abteilung Ökosystemmodellierung"],["dc.subject.gro","Independence null model"],["dc.subject.gro","Individual species-area relationship"],["dc.subject.gro","Neighborhood diversity"],["dc.subject.gro","Point pattern analysis"],["dc.subject.gro","Sinharaja tropical forest"],["dc.subject.gro","Spatial scale"],["dc.subject.gro","Stochastic dilution"],["dc.title","Neighborhood diversity of large trees shows independent species patterns in a mixed dipterocarp forest in Sri Lanka"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]