Biology subjects

Decker, O.

Publications and source records attributed to Decker, O..

8 recordsLinked to original sources

bioRxiv2025

Microclimatic heterogeneity is associated with forest structural complexity and biodiversity

Forest microclimates, their dependence on forest structure, and their impact on biodiversity are crucial for future forest management under climate change. However, standard approaches for measuring forest microclimates do not capture within-plot heterogeneity, which, according to the habitat heterogeneity hypothesis, is a key driver of local biodiversity. We quantified horizontal and vertical microclimatic heterogeneity within 30 broad-leaved forest plots in Central Europe using a three-dimensional design with high spatial resolution. Moreover, we examined whether microclimatic heterogeneity differs among silvicultural treatments and whether it can be predicted using forest structure indices derived from laser scanning. Additionally, we explored the relationship between microclimatic heterogeneity and biodiversity. In the understory of canopy gaps, warm and cold habitats co-existed in close proximity, leading to a high horizontal microclimatic heterogeneity. In closed stands with high structural complexity, we found steep gradients of increasing temperature and vapor pressure deficit from the ground to the canopy during mid-day. Canopy cover and forest structural complexity were strong indicators of microclimatic heterogeneity. We found positive relationships between herb layer temperature heterogeneity and the diversity of plants, Hymenoptera, and Diptera. Our results demonstrate that single-point measurements fail to capture the substantial microclimatic heterogeneity within plots, potentially misrepresenting the conditions experienced by forest species. However, laser scanning provides reliable indicators for within- plot microclimatic heterogeneity. With canopy gaps featuring high horizontal microclimatic heterogeneity and promoting the biodiversity of several taxonomic groups, we argue that managing forests for maximized temperature buffering should not be the only strategy to conserve forest biodiversity. HighlightsO_LIHigh small-scale horizontal microclimatic heterogeneity in canopy gaps C_LIO_LISteep vertical microclimatic gradients in closed-canopy forests C_LIO_LICanopy cover and structural complexity: indicators for microclimatic heterogeneity C_LIO_LIPositive relationship between herb layer temperature heterogeneity and biodiversity C_LI

ecology↗

bioRxiv2025

Forest vertical and horizontal temperature similarity drives arthropod communities in a managed temperate forest

Manipulating the canopy structure is the core tool of silviculture operation, and with that, changing the light availability alters temperature dynamics from the forest floor to the canopy. This should affect communities of ectothermic organisms such as insects, but we lack information on insect distributions in the complex 3D space of forests. Therefore, we set up temperature loggers and insect traps vertically (flight-interception traps) and horizontally (pitfall traps) in forests with experimental thinning and gap felling 8 years after the intervention. By metabarcoding, we identified [~]10,600 Operational Taxonomic Units (OTUs) from 44 orders including [~]2450 arthropods assigned to species in our 426 samples. Arthropod community similarity matrices were quantified along the Hill numbers accounting for rare to dominant species and under consideration of incomplete samples. Arthropod communities were shaped by stratification (height above ground 0 m, 2 m, 10 m, 15 m), and by temperature similarity. Average nighttime temperature was the most important temperature variable for overall arthropod community similarity metrics. Restricted to flight interception traps, flying insect communities responded to daily temperature maximum and nighttime average temperature. Restricted to pitfall traps, on the other hand, arthropod communities were shaped by the overall temperature metric only when focusing on rare species. Additionally, all communities were strongly affected by season. Our results implies that management interventions establish different temperature heterogeneity within forest patches, which ultimately could drive species community similarity when including all arthropods in the area between forest floor and canopy.

ecology↗

bioRxiv2025

Old growth attributes by chain saw: how between-patch heterogeneity changes the metacommunities of beetles in temperate forests

Metacommunity theory has expanded our understanding of how spatial dynamics and local interactions influence species communities. Different assembly archetypes, reflecting different roles of species differences, habitat differences, and dispersal have been described, but we lack empirical studies specifically in terrestrial habitats testing which archetype is most important. In a replicated design we experimentally enhanced structural between-patch heterogeneity in homogeneous production forests and developed a statistical framework controlling for sample incompleteness to detect different metacommunity processes. Meta-analyses on >100K individuals of >1.3K beetle species showed an increase of [~]60 species in heterogenized forests at {gamma}-level promoted by increasing -diversity consistent with the mass-effect and an increase of {beta}-diversity by [~]10% supporting species-sorting. Additionally, we tested {beta}-deviations from random assembly as a proxy of neutral processes. Findings indicate that enhancing structural heterogeneity can shift forests from patch-dynamics dominance towards mass-effect and species-sorting, offering a promising pathway to restore biodiversity in managed landscapes.

ecology↗

bioRxiv2025

Enhanced forest heterogeneity drives stronger functional than taxonomic shifts in soil nematodes

Production forests are often managed primarily for timber production, leading to biotic homogenization and reduced biodiversity. To explore strategies that promote biodiversity while maintaining timber yields, we conducted a large-scale experiment in eight German forests. We manipulated structural {beta}-complexity, i.e., the heterogeneity of structural elements across forest patches, by experimentally introducing variation in canopy gaps and different types of deadwood across 156 plots of 50 x 50 m each, to investigate its effects on forest biodiversity. We analyzed soil nematode communities, which are important bioindicators and contributors to ecosystem processes, by assessing taxonomic and functional diversity across patch (), site ({gamma}), and between-patch ({beta}) scales using Hill-Chao numbers. Additionally, we tested whether environmental variables explain nematode diversity responses. Our results show that functional diversity is more responsive than taxonomic diversity, with increased {beta}-diversity of common and frequent taxa alongside simultaneous declines in - and {gamma}-diversity. This pattern suggests a shift toward more specialized nematode communities in response to the intervention. Moreover, we found that site-specific conditions, such as sand content and understory biomass, modulated these effects. Overall, our findings reveal complex, scale-dependent responses of nematode diversity to aboveground forest structural changes, emphasizing the need to consider environmental context in forest biodiversity management. This study represents an important first step toward understanding and enhancing soil biodiversity at management-relevant spatial scales.

ecology↗

bioRxiv2025

Higher bat and bird γ-diversity in structurally complex forests is driven by distinct α- and β-diversity responses

Effective conservation management and habitat restoration rely on understanding how biodiversity responds to environmental change. Centuries of silviculture have homogenized forests and their species communities globally, reducing biodiversity. To test whether restoring forest structural complexity can promote biodiversity, we conducted a large-scale, spatially explicit landscape experiment. At 11 sites across Germany, we compared bat and bird diversity in forests with experimentally enhanced heterogeneity by increasing deadwood and canopy complexity to homogeneous production forests. Both taxa were investigated by autonomous acoustic recorders and automatic species identification. We quantified within-patch (-), between-patch ({beta}-), and landscape-level ({gamma}-) diversity, emphasizing infrequent to highly frequent species for taxonomic, functional, and phylogenetic diversity. The pairwise comparisons of the sites were synthesized using a newly developed meta-analysis of rarefaction-extrapolation curves. {gamma}-diversity increased significantly in structurally heterogeneous forests for both taxa, albeit through distinct taxon-specific mechanisms. Bat {gamma}-diversity gains were primarily driven by higher {beta}-diversity, indicating greater dissimilarity in species assemblages among patches, while bird {gamma}-diversity increased via higher -diversity within patches. Bat diversity increases were mainly taxonomic, suggesting functional similarity in the communities, whereas birds showed the highest gains in functional diversity, indicating that experimental treatments resulted in greater trait dissimilarity. Our results provide experimental evidence under real-world conditions that {gamma}-diversity can be shaped by different diversity mechanisms. These patterns likely originate from differences in activity ranges, such as the large-scale movements of foraging bats in contrast to the more spatially restricted, territorial behavior of birds. This highlights the need for taxon-specific restoration strategies in homogenized landscapes.

ecology↗

bioRxiv2025

Dung beetles do not profit from enhanced spatial heterogeneity in production forests: a large-scale forest manipulation experiment

O_LICentral European forest management strategies promoting structurally homogeneous closed-canopy forests have led to landscape-level declines in biodiversity and ecosystem multifunctionality. Conservation-targeted management programs aim at reintroducing structural heterogeneity into production forests, however, it is not well understood if species diversity and ecosystem functions generally profit from management promoting heterogeneity in forest structure. By removing and processing mammalian dung remains, dung beetles play an integral role in ecosystem functions in forests. C_LIO_LIIn one of the largest manipulative forest experiments in Central Europe to date, we analysed the effects of enhanced structural heterogeneity in production forests, climate, and mammalian defecation on dung beetle diversity and dung removal rates at the local and landscape level. We assessed communities of dung beetles and dung removal rates on 234 study patches (50 x 50 m) in eleven paired forest landscapes across a climatic gradient in Germany. Forest landscapes were either managed to conserve a homogeneous closed canopy or to create a heterogeneous forest structure with forest patches varying in canopy coverage and dead wood availability. C_LIO_LIWe did not find that more heterogeneously managed forests had higher dung beetle species diversity and dung removal rates. Canopy openings did not increase species turnover but decreased species diversity. C_LIO_LIAlong the climate gradient, dung beetle average biomass and dung removal decreased with increasing temperature. Canopy openings in combination with higher temperatures negatively impacted all abundant dung beetle species, but especially the large species Anoplotrupes stercorosus, comprising > 90% of the total dung beetle biomass. C_LIO_LISynthesis and application: Our results suggest that dung beetles do not profit from management increasing the structural heterogeneity of forests. Due to a restricted climate and habitat niche of the current Central European dung beetle fauna, future warming and openings in forest structure might have negative effects on dung beetles and consequently on the ecosystem services they provide in Central European production forests. C_LI

ecology↗

bioRxiv2025

Inconsistent short-term effects of enhanced structural complexity on soil microbial properties across German forests

Structural and biotic homogenization can result from forestry practices that lack promotion of canopy gaps and deadwood. This can lead to biodiversity loss and impaired ecosystem functions. Enhancing structural complexity (ESC) has been proposed to counteract these effects, but its impact on soil properties remains insufficiently understood. Overall, we hypothesize that ESC enhances soil abiotic properties, their spatial variability, and microbial functioning, with effects modulated by environmental context and increasing over time. Data were collected from 148 patches (50 x 50 m) in eight beech forests across Germany. In half of the patches, structural complexity was enhanced by felling 30% of the basal area of living trees through two spatial patterns--aggregated (one large gap) and distributed (small gaps)--combined with leaving or removing deadwood (stumps, logs, and snags). The other half served as controls, representing typically managed, homogeneous production forests. Soil C:N, C%, and N% increased near deadwood. Soil microbial biomass and activity were significantly affected in three of eight forest sites, with effects ranging from -30% to +62%. Higher soil water content was associated with increased microbial biomass, and greater understorey biomass correlated with a lower microbial respiratory quotient. No temporal trends were observed over five years. Although soil properties showed resistance to structural interventions, site-specific effects underline the importance of soil moisture and the understorey vegetation for microbial functioning. Further research building on our results is needed to develop practical forest management strategies to clarify how structural complexity may support soil functioning and ecosystem resilience. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=127 SRC="FIGDIR/small/664741v1_ufig1.gif" ALT="Figure 1"> View larger version (53K): org.highwire.dtl.DTLVardef@10790f2org.highwire.dtl.DTLVardef@1bd2f95org.highwire.dtl.DTLVardef@17eed6dorg.highwire.dtl.DTLVardef@15a049_HPS_FORMAT_FIGEXP M_FIG C_FIG Highlights- Deadwood addition increases soil C%, N%, and the soil C:N ratio - Enhanced structural complexity alters soil microbial properties in site-specific ways - Soil water content changes are linked to shifts in microbial biomass - Understorey biomass changes are linked to shifts in the respiratory quotient

ecology↗

bioRxiv2024

Chromatin regulator HELLS mediates SSB repair and responses to DNA alkylation damage.

The SNF2 family chromatin remodeler HELLS has emerged as an important regulator of cell proliferation, genome stability, and several cancer pathways. Significant upregulation of HELLS has been reported in 33 human cancer types. While HELLS has been implicated in DNA damage response, its function in DNA repair is poorly understood. Here we report a new regulatory link between HELLS and single-strand break (SSB) repair in cellular responses to DNA alkylation damage. We found that loss of HELLS impairs SSB repair, and selectively sensitizes cells to DNA alkylating agents and PARP inhibitors (PARPi). Furthermore, we found that HELLS is co-expressed with PARP1 in cancer cells, and its loss is synthetic lethal with homologous recombination deficiency (HRD). This work unveils new functions of HELLS in modulating SSB repair and responses to clinically relevant DNA alkylation damage, thus offering new insights into the potential therapeutic value of targeting HELLS in cancer. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=158 SRC="FIGDIR/small/629292v2_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@2bbd3eorg.highwire.dtl.DTLVardef@1956f14org.highwire.dtl.DTLVardef@1afcb7corg.highwire.dtl.DTLVardef@58504c_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗