Biology subjects

Baeten, L.

Publications and source records attributed to Baeten, L..

3 recordsLinked to original sources

bioRxiv2025

Multitaxon assessment reveals inconsistent biodiversity responses to forest structural complexity in temperate forests

Increasing forest structural complexity is a key objective of future-proof forest management, with potential benefits for biodiversity. However, empirical evidence for consistent biodiversity-structure relationships across taxa is still limited. We investigated whether structurally more complex forests support greater species richness and higher multidiversity across taxonomic and functional groups in 19 mature forest plots in Flanders, Belgium. As one of the most densely populated and urbanized regions in Europe, with limited and highly fragmented forest cover, Flanders provides a particularly informative and policy-relevant context to test structure-biodiversity relationships. Its forests, often dominated by a few tree species and subject to long-term anthropogenic pressures and management, represent a realistic gradient of structural complexity. Structural complexity was quantified using a Structural Complexity Index (SCI), and biodiversity was assessed using a multidiversity index integrating scaled species richness across five taxonomic and seven arthropod functional groups. Using mixed-effects models and multivariate Bayesian analyses, we tested both direct effects of SCI on biodiversity and the covariation in species richness among groups. Contrary to expectations, SCI was not a consistent predictor of multidiversity, and most groups showed weak or inconsistent responses. These findings might suggest that structural complexity alone may be insufficient to enhance biodiversity in simplified forests. HighlightsO_LIForest structural complexity does not consistently predict biodiversity. C_LIO_LIResponses vary among taxonomic and functional groups. C_LIO_LICross-taxon congruence in diversity is limited and scale-dependent. C_LIO_LIKeywords: Forest structural complexity; Multidiversity, Species richness; Functional groups; Sustainable forest management C_LI

ecology↗

bioRxiv2024

Multi-year drought strengthens positive and negative functional diversity effects on tree growth response

O_LIMixed-species forests are proposed as strategy to increase the resistance and resilience of forests to drought stress. However, evidence suggest that increasing tree species richness does not consistently enhance tree growth responses to drought. Moreover, tree diversity effects under unprecedented multiyear droughts remain uncertain, calling for a better understanding of the underlying processes. C_LIO_LIHere, we used a network of planted tree diversity experiments to investigate how drought-induced growth responses of individual trees are influenced by neighborhood tree diversity and the functional traits of the focal tree species. We analyzed tree cores (948 trees across 16 species) from nine experiments across Europe featuring gradients of tree species richness (1-6 species), which experienced severe droughts in recent years. Radial growth response to drought was quantified as tree-ring biomass increment using X-ray computed tomography. We applied hydraulic trait-based growth models to analyze single-year drought responses across all sites and site-specific responses during consecutive drought years for six sites as a function of neighborhood tree diversity. C_LIO_LIThe large variability in tree growth responses to a single-year drought was partially explained by the focal species hydraulic safety margin (representing species drought tolerance) and drought intensity, but independent of neighborhood species richness or functional trait diversity. However, tree diversity effects on growth responses strengthened during consecutive drought years and were site-specific, with contrasting direction (both positive and negative). This indicated opposing pathways of diversity effects under consecutive drought events, possibly resulting from competitive release or greater water consumption in diverse mixtures. C_LIO_LIWe conclude that tree diversity effects on growth responses to single-year droughts may differ considerably from responses to consecutive drought years. Our study highlights the need to consider trait-based approaches (specifically, hydraulic traits) and tree neighborhood scale processes to understand the multifaceted growth responses of tree mixtures under prolonged drought stress. C_LI

ecology↗

bioRxiv2024

Ixodes ricinus nymphs prefer blood with Borrelia infection and low corticosteroid concentration

Ticks play a significant role in the transmission of various pathogens, impacting both human and animal health. Understanding the factors influencing tick feeding preferences is crucial for mitigating the risk of tick-borne diseases. This study investigates the blood preference of Ixodes ricinus nymphs, focusing on host species, stress hormone levels (glucocorticoids), and the presence of Borrelia burgdorferi bacteria. Three series of in vitro experiments were conducted. The setup involved placing individual blood drops (15 {micro}l) on filter paper over a 37{degrees}C plate. Ticks were placed in the center, and their movements were tracked for two minutes to record preferences. The first experiment evaluated the ticks preference for blood from different hosts (mouse, bird, sheep). The second experiment explored the role of stress hormones by assessing the ticks response to blood with varying levels of supplemented cortisol and corticosterone (0, 10, 100 and 1000 ng/ml). The third experiment examined the potential influence of Borrelia infection, combined with elevated stress hormone levels, on blood preference. Our results show that I. ricinus nymphs show a significant preference for blood without added glucocorticoids and, in mice, blood with Borrelia infection. No clear preference for a specific host species was observed. These findings provide valuable insights into the complex interactions between ticks, blood characteristics, and Borrelia infection status, highlighting the potential importance of host physiological state in tick host selection. Future studies should explore the mechanisms behind these preferences, which could lead to the development of new methods to control the spread of tick-borne diseases. HIGHLIGHTSO_LIIn vitro experiments with nymphs can reveal insights into their blood preferences C_LIO_LITicks displayed no difference in preference towards bird, mouse, or sheep blood C_LIO_LITicks prefer blood with baseline stress levels over increased stress levels C_LIO_LIMouse blood infected with Borrelia burgdorferi was preferred by ticks C_LI

ecology↗