TY  - JOUR
A1  - Viljur, Mari‐Liis
A1  - Abella, Scott R.
A1  - Adámek, Martin
A1  - Alencar, Janderson Batista Rodrigues
A1  - Barber, Nicholas A.
A1  - Beudert, Burkhard
A1  - Burkle, Laura A.
A1  - Cagnolo, Luciano
A1  - Campos, Brent R.
A1  - Chao, Anne
A1  - Chergui, Brahim
A1  - Choi, Chang‐Yong
A1  - Cleary, Daniel F. R.
A1  - Davis, Thomas Seth
A1  - Dechnik‐Vázquez, Yanus A.
A1  - Downing, William M.
A1  - Fuentes‐Ramirez, Andrés
A1  - Gandhi, Kamal J. K.
A1  - Gehring, Catherine
A1  - Georgiev, Kostadin B.
A1  - Gimbutas, Mark
A1  - Gongalsky, Konstantin B.
A1  - Gorbunova, Anastasiya Y.
A1  - Greenberg, Cathryn H.
A1  - Hylander, Kristoffer
A1  - Jules, Erik S.
A1  - Korobushkin, Daniil I.
A1  - Köster, Kajar
A1  - Kurth, Valerie
A1  - Lanham, Joseph Drew
A1  - Lazarina, Maria
A1  - Leverkus, Alexandro B.
A1  - Lindenmayer, David
A1  - Marra, Daniel Magnabosco
A1  - Martín‐Pinto, Pablo
A1  - Meave, Jorge A.
A1  - Moretti, Marco
A1  - Nam, Hyun‐Young
A1  - Obrist, Martin K.
A1  - Petanidou, Theodora
A1  - Pons, Pere
A1  - Potts, Simon G.
A1  - Rapoport, Irina B.
A1  - Rhoades, Paul R.
A1  - Richter, Clark
A1  - Saifutdinov, Ruslan A.
A1  - Sanders, Nathan J.
A1  - Santos, Xavier
A1  - Steel, Zachary
A1  - Tavella, Julia
A1  - Wendenburg, Clara
A1  - Wermelinger, Beat
A1  - Zaitsev, Andrey S.
A1  - Thorn, Simon
T1  - The effect of natural disturbances on forest biodiversity: an ecological synthesis
JF  - Biological Reviews
N2  - Disturbances alter biodiversity via their specific characteristics, including severity and extent in the landscape, which act at different temporal and spatial scales. Biodiversity response to disturbance also depends on the community characteristics and habitat requirements of species. Untangling the mechanistic interplay of these factors has guided disturbance ecology for decades, generating mixed scientific evidence of biodiversity responses to disturbance. Understanding the impact of natural disturbances on biodiversity is increasingly important due to human‐induced changes in natural disturbance regimes. In many areas, major natural forest disturbances, such as wildfires, windstorms, and insect outbreaks, are becoming more frequent, intense, severe, and widespread due to climate change and land‐use change. Conversely, the suppression of natural disturbances threatens disturbance‐dependent biota. Using a meta‐analytic approach, we analysed a global data set (with most sampling concentrated in temperate and boreal secondary forests) of species assemblages of 26 taxonomic groups, including plants, animals, and fungi collected from forests affected by wildfires, windstorms, and insect outbreaks. The overall effect of natural disturbances on α‐diversity did not differ significantly from zero, but some taxonomic groups responded positively to disturbance, while others tended to respond negatively. Disturbance was beneficial for taxonomic groups preferring conditions associated with open canopies (e.g. hymenopterans and hoverflies), whereas ground‐dwelling groups and/or groups typically associated with shady conditions (e.g. epigeic lichens and mycorrhizal fungi) were more likely to be negatively impacted by disturbance. Across all taxonomic groups, the highest α‐diversity in disturbed forest patches occurred under moderate disturbance severity, i.e. with approximately 55% of trees killed by disturbance. We further extended our meta‐analysis by applying a unified diversity concept based on Hill numbers to estimate α‐diversity changes in different taxonomic groups across a gradient of disturbance severity measured at the stand scale and incorporating other disturbance features. We found that disturbance severity negatively affected diversity for Hill number q = 0 but not for q = 1 and q = 2, indicating that diversity–disturbance relationships are shaped by species relative abundances. Our synthesis of α‐diversity was extended by a synthesis of disturbance‐induced change in species assemblages, and revealed that disturbance changes the β‐diversity of multiple taxonomic groups, including some groups that were not affected at the α‐diversity level (birds and woody plants). Finally, we used mixed rarefaction/extrapolation to estimate biodiversity change as a function of the proportion of forests that were disturbed, i.e. the disturbance extent measured at the landscape scale. The comparison of intact and naturally disturbed forests revealed that both types of forests provide habitat for unique species assemblages, whereas species diversity in the mixture of disturbed and undisturbed forests peaked at intermediate values of disturbance extent in the simulated landscape. Hence, the relationship between α‐diversity and disturbance severity in disturbed forest stands was strikingly similar to the relationship between species richness and disturbance extent in a landscape consisting of both disturbed and undisturbed forest habitats. This result suggests that both moderate disturbance severity and moderate disturbance extent support the highest levels of biodiversity in contemporary forest landscapes.
KW  - natural disturbance
KW  - diversity–disturbance relationship
KW  - disturbance severity
KW  - disturbance extent
KW  - intermediate disturbance hypothesis
KW  - forest communities
KW  - α‐diversity
KW  - β‐diversity
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-287168
VL  - 97
IS  - 5
SP  - 1930
EP  - 1947
ER  - 
TY  - JOUR
A1  - Kollmann, Catherine
A1  - Buerkert, Hannah
A1  - Meir, Michael
A1  - Richter, Konstantin
A1  - Kretzschmar, Kai
A1  - Flemming, Sven
A1  - Kelm, Matthias
A1  - Germer, Christoph-Thomas
A1  - Otto, Christoph
A1  - Burkard, Natalie
A1  - Schlegel, Nicolas
T1  - Human organoids are superior to cell culture models for intestinal barrier research
JF  - Frontiers in Cell and Developmental Biology
N2  - Loss of intestinal epithelial barrier function is a hallmark in digestive tract inflammation. The detailed mechanisms remain unclear due to the lack of suitable cell-based models in barrier research. Here we performed a detailed functional characterization of human intestinal organoid cultures under different conditions with the aim to suggest an optimized ex-vivo model to further analyse inflammation-induced intestinal epithelial barrier dysfunction. Differentiated Caco2 cells as a traditional model for intestinal epithelial barrier research displayed mature barrier functions which were reduced after challenge with cytomix (TNFα, IFN-γ, IL-1ß) to mimic inflammatory conditions. Human intestinal organoids grown in culture medium were highly proliferative, displayed high levels of LGR5 with overall low rates of intercellular adhesion and immature barrier function resembling conditions usually found in intestinal crypts. WNT-depletion resulted in the differentiation of intestinal organoids with reduced LGR5 levels and upregulation of markers representing the presence of all cell types present along the crypt-villus axis. This was paralleled by barrier maturation with junctional proteins regularly distributed at the cell borders. Application of cytomix in immature human intestinal organoid cultures resulted in reduced barrier function that was accompanied with cell fragmentation, cell death and overall loss of junctional proteins, demonstrating a high susceptibility of the organoid culture to inflammatory stimuli. In differentiated organoid cultures, cytomix induced a hierarchical sequence of changes beginning with loss of cell adhesion, redistribution of junctional proteins from the cell border, protein degradation which was accompanied by loss of epithelial barrier function. Cell viability was observed to decrease with time but was preserved when initial barrier changes were evident. In summary, differentiated intestinal organoid cultures represent an optimized human ex-vivo model which allows a comprehensive reflection to the situation observed in patients with intestinal inflammation. Our data suggest a hierarchical sequence of inflammation-induced intestinal barrier dysfunction starting with loss of intercellular adhesion, followed by redistribution and loss of junctional proteins resulting in reduced barrier function with consecutive epithelial death.
KW  - intestinal epithelial barrier
KW  - Caco2 cells
KW  - intestinal organoids
KW  - enteroids
KW  - gut barrier
KW  - inflammatory cell model
KW  - inflammation
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-357317
SN  - 2296-634X
VL  - 11
ER  -