Biology subjects

Sachsenmaier, L.

Publications and source records attributed to Sachsenmaier, L..

3 recordsLinked to original sources

bioRxiv2024

Intraspecific and intraindividual trait variability decrease with tree species richness in a subtropical tree biodiversity experiment

Phenotypic variability within tree species responds to local tree species richness. However, we lack evidence on how different sources of trait variation shape tree-tree interactions. Along a diversity gradient from one to eight tree species, we sampled 4,568 leaves from 381 trees to study changes in intraspecific and intraindividual leaf trait variability and assessed their contribution to community functional diversity. Intraspecific variability decreased with tree species richness, while intraindividual variability barely responded. Functional overlap between conspecific trees increased with tree species richness and through intraindividual variation, but was reduced through intraspecific variability, meaning that intraspecific variability may reduce intraspecific competitive interactions while intraindividual variability could arise due to varying microenvironmental conditions within the canopy. Last, intraspecific and intraindividual variability explained high community functional richness and divergence, respectively, especially in mixtures. Our findings emphasize that fine-scale variability influences tree-tree interactions and can be a driver of local functional diversity. TeaserTrait variability within tree species decreases with diversity and explains high forest functional diversity.

ecology↗

bioRxiv2024

Forest growth resistance and resilience to the 2018-2020 drought depend on tree diversity and mycorrhizal type

O_LIThe frequency of consecutive drought years is predicted to increase due to climate change. These droughts have strong negative impacts on forest ecosystems. Mixing tree species is proposed to increase the drought resistance and resilience of tree communities. However, this promising diversity effect has not yet been investigated under extreme drought conditions and in the context of complementary mycorrhizal associations and their potential role in enhancing water uptake. C_LIO_LIHere, we investigate whether tree diversity promotes growth resistance and resilience to extreme drought and whether drought responses are modulated by mycorrhizal associations. We used inventory data (2015 - 2021) of a young tree diversity experiment in Germany, manipulating tree species richness (1, 2, 4 species) and mycorrhizal type (communities containing arbuscular mycorrhizal (AM) or ectomycorrhizal (EM) tree species, or both). For all tree communities, we calculated basal area increment (BAI) in the periods before, during, and after the drought and used the concepts of resistance and resilience to quantify growth responses to drought. C_LIO_LIWe found strong growth declines during the extreme 2018-2020 drought for most of the tree communities. Contrary to our hypothesis, we did not find that tree species richness per se can buffer the negative impacts of extreme drought on tree growth. However, while for EM communities, drought resistance, and resilience decreased with tree species richness, they increased for AM communities and communities comprising both mycorrhizal types. We highlight that among various tree species mixtures, only those with mixed mycorrhizal types outperformed their respective monocultures during and after drought. Further, under extreme drought, the community tends to segregate into "winner" and "loser" tree species in terms of diversity, indicating a potential intensification of competition. C_LIO_LIWhile we cannot disentangle the underlying mechanisms, or clarify the role of mycorrhiza during drought, our findings suggest that mixtures of mycorrhizal types within tree communities could help safeguard forests against increasing drought frequency. C_LIO_LISynthesis: Drought resistance and resilience of tree communities depend on tree diversity and mycorrhizal association types. Mixing tree species with diverse mycorrhizal types holds promise for forest restoration in the face of climate change. C_LI

ecology↗

bioRxiv2022

Landscape heterogeneity and soil biota are central to multi-taxa diversity for landscape restoration

How to enhance biodiversity in monoculture-dominated landscapes is a key sustainability question that requires considering the spatial organization of ecological communities (beta diversity). Here, we experimentally tested if increasing landscape heterogeneity - through tree islands - is a suitable landscape restoration strategy when aiming to enhance multi-taxa diversity. We found that multi-taxa diversity resulted from islands fostering unique species (turnover: between 0.18 - 0.73) rather than species losses and gains (nestedness: between 0.03 - 0.34), suggesting that tree islands enhance diversity at the landscape scale. Through partial correlation networks, we revealed that landscape heterogeneity is associated with multi-taxa diversity (strength = 0.84). Soil biota were also central to the overall community by connecting beta diversity patterns across taxa. Our results show that increasing landscape heterogeneity enhances multi-taxa diversity in monoculture-dominant landscapes. Furthermore, we highlight that strategies aiming to enhance multi-taxa diversity should consider that spatial distributions of above- and below-ground communities are associated.

ecology↗