Biology subjects

Hanusch, M.

Publications and source records attributed to Hanusch, M..

7 recordsLinked to original sources

bioRxiv2026

Chemodiversity is an independent synecological dimension of plant form and function

Plant trait spaces have advanced ecology by reducing the vast diversity of plant form and function to a few axes of trait variation. Yet, such frameworks remain dominated by autoecological traits related to resource acquisition and growth, while largely overlooking the traits mediating interactions with other organisms. Chemodiversity, the richness, evenness and chemical disparity of volatile organic compounds (VOCs) emitted by leaves and flowers to attract, deter, or otherwise affect biotic interaction partners, may represent such an overlooked synecological dimension of plant functional variation. By integrating the chemodiversity of floral (n = 859 species) and vegetative (n = 159 species) VOC profiles into the global spectrum of plant form and function, we show that chemodiversity is a) independent from the classical axis of variation in plant size and leaf economics but b) is linked to biotic interactions in organ-specific ways. Flower-visitor richness increases with floral scent chemodiversity, a pattern supported by an analysis of global interaction data and a meta-analysis of the specialization and generalization of flower-animal interactions. Vegetative VOC chemodiversity has context-dependent positive and negative effects on herbivore richness. VOC chemodiversity represents a distinct ecological strategy that defines interaction niches, thereby contributing to ecological differentiation and coexistence among otherwise functionally similar species.

ecology↗

bioRxiv2026

Common, species-specific, and accession-specific responses of foliar phytohormones and morphological traits to drought and herbivory

BackgroundPlants are exposed to various environmental challenges. With ongoing climate change, droughts and insect outbreaks are expected to become more frequent. Thus, a better understanding is needed of how different plant species respond to such single and combined challenges. This study investigated common versus species-specific responses to environmental challenges in three perennial plant species of different growth forms and whether responses differ intraspecifically among accessions. Clones of different accessions of the herbaceous species Tanacetum vulgare, the woody vine Solanum dulcamara, and the tree Populus nigra were subjected to similar control, herbivory, drought, and combined (drought and herbivory) treatments for the same periods. After the exposure, concentrations of foliar phytohormones and various morphological traits were measured. ResultsAcross all species, several foliar phytohormones and one of ten morphological traits responded consistently to the environmental challenges. Jasmonoyl-isoleucine was induced by herbivory and the combined treatment, abscisic acid (ABA) by drought and the combined treatment, and indole acetic acid by the combined treatment in all species. Root mass remained unchanged in all species. However, structural equation models (SEMs) revealed a shared regulatory pathway across species in which ABA connected treatment and root mass, indicating a common hormonal response potentially linking challenges to growth responses. Despite these common patterns, species-specific responses were pronounced. In P. nigra, a unique induction of salicylic acid was found under the combined treatment, while aboveground mass and root-shoot ratio remained unaffected by any treatment, in contrast to the other two species. Species-specific SEMs further indicated distinct phytohormone-mediated pathways underlying morphological variation. Phenotypic plasticity reflected these species-specific patterns, with none of the phytohormones or morphological traits exhibiting uniform plasticity across species. Intraspecific variation further shaped responses, as phytohormone and morphological trait plasticity depended on accession, indicating substantial accession-specific plant responses. ConclusionsOur results indicate that some responses to comparable challenges may be conserved across species, while others are species-specific. The combined treatment elicited the most pronounced responses, and such complex responses may become more frequent under current global change. Our study highlights that comprehensive understanding of plant responses requires systematic comparisons at both interspecific and intraspecific scales.

ecology↗

bioRxiv2026

Habitat heterogeneity responds to megaherbivores in East African coastal forests, but vegetation composition remains constrained by land-use history

O_LIMegaherbivores are increasingly promoted as agents of nature restoration, yet most research on their ecological effects has focused on temperate and non-forested systems, with limited consideration of tropical forests and their historical land-use contexts. C_LIO_LIA better understanding of megaherbivore impacts in tropical forests is essential to inform rewilding and restoration efforts. This is particularly important in regenerating secondary systems that historically supported megafaunga and remain highly valuable targets for ecological recovery. C_LIO_LIWe address this knowledge gap by comparing tree species composition, forest structural attributes, and understory habitat composition across three disturbance regimes in an East African tropical dry forest: (1) primary forest with megaherbivores, (2) secondary forest with megaherbivores, and (3) primary forest without megaherbivores. C_LIO_LIUnder megaherbivore presence, understory habitat and tree branching architecture converged across primary and secondary forests, suggesting functional consistency in disturbance effects imposed by large herbivores and indicating that key structural ecosystem processes can be rapidly restored. In contrast, canopy structure and tree species composition remained distinct between forest types and strongly constrained by persistent legacies of past human land use. C_LIO_LIOur findings underscore that restoration strategies relying on megaherbivores must explicitly account for historical land-use constraints rather than assuming spontaneous convergence toward primary-forest conditions. C_LI

ecology↗

bioRxiv2024

Coexistence despite competition: Bryophyte diversity is buffered against vascular plant dominance over succession.

Vascular plants and bryophytes are among the first colonizers of deglaciated landscapes, thus playing fundamental roles in ecological succession. Understanding biotic interactions between these groups is essential for comprehending the emergence of diverse and complex ecosystems. Set within a 170-year primary succession gradient in a glacier forefield in the Austrian Alps, this study investigates interactions between vascular plants and bryophytes during early ecosystem development. Data on vegetation structural complexity, obtained through high-resolution 3D-laser scanning, were combined with estimates of local substrate diversity, and the taxonomic and functional composition of vascular plants. This integrated approach allowed us to obtain a mechanistic understanding on the competitive interactions shaping bryophyte diversity over the course of primary succession. Competitive interactions between vascular plants and bryophytes were uniquely detected through a metric of vegetation structural complexity, while traditional community metrics of vascular plant cover, richness, composition, and functional diversity, failed to reveal these patterns. Path analysis shows that increasing vegetation structural complexity homogenizes local habitat conditions and constrains the realized ecological niche of bryophyte species, while substrate diversity acts as a buffer against vascular plant dominance. This mechanism was quantified using ecological dispersion, a novel concept introduced in this study that estimates the variability of growth optima within a community. Synthesis: This study highlights the additional value of quantifying the structural properties of plant communities through 3D-laser scanning in explaining ecosystem dynamics. By demonstrating its applicability in grassland ecosystems under field conditions, it underscores the potential of high-resolution remote sensing to advance vegetation structural research. The findings establish vegetation structural complexity as a key factor shaping plant-plant interactions in grasslands, influencing both ecosystem development and biodiversity patterns. These insights may provide valuable guidance for succession-based restoration strategies.

ecology↗

bioRxiv2021

Accuracy of mutual predictions of plant and microbe communities varies along a successional gradient in an alpine glacier forefield

O_LIDue to climate warming, recently deglaciated glacier forefields create virtually uninhabited substrates waiting for initial colonization of bacteria, fungi and plants and serve as an ideal ecosystem for studying transformations in community composition and diversity over time and the interactions between taxonomic groups. C_LIO_LIIn this study, we investigated the composition and diversity of bacteria, and fungi, plants and environmental factors (pH, temperature, plot age and soil nutrients) along a 1.5km glacier forefield. We used random forest analysis to detect how well the composition and diversity of taxonomic groups and environmental factors can be mutually predicted. C_LIO_LICommunity composition and diversity of taxonomic groups predicted each other more accurately than environmental factors predicted the taxonomic groups; within the taxonomic groups bacteria and fungi predicted each other best and the taxas composition was better predicted than diversity indices. Additionally, accuracy of prediction among taxonomic groups and environmental factors considerably varied along the successional gradient. C_LIO_LIAlthough our results are no direct indication of interactions between the taxa investigated and the environmental conditions, the accurate predictions among bacteria, fungi, and plants do provide insights into the concerted community assembly of different taxa in response to changing environments along a successional gradient. C_LI

ecology↗

bioRxiv2021

Divergent assembly trajectories: a comparison of the plant and soil microbiome with plant communities in a glacier forefield

Community assembly is a result of dispersal, abiotic and biotic characteristics of the habitat as well as stochasticity. A direct comparison between the assembly of microbial and macrobial organisms is hampered by the sampling of these communities in different studies, at different sites, or on different scales. In a glacier forefield in the Austrian Alps, we recorded the soil and plant microbiome (bacteria and fungi) and plants that occurred in the same landscape and in close proximity in the same plots. We tested five predictions deduced from assembly processes and revealed deviating patterns of assembly in these community types. In short, microbes appeared to be less dispersal limited than plants, soil microbes and plants strongly responded to abiotic factors whereas the leaf microbiome was plant species-specific and well buffered from environmental conditions. The observed differences in community assembly processes may be attributed to the organisms dispersal abilities, the exposure of the habitats to airborne propagules, and habitat characteristics. The finding that assembly is conditional to the characteristics of the organisms, the habitat, and the spatial scale under consideration is thus central for our understanding about the establishment and the maintenance of biodiversity.

ecology↗

bioRxiv2021

Succession comprises a sequence of threshold-induced community assembly processes towards multidiversity

Research on successions and community assembly both address the same processes such as dispersal, species sorting, and biotic interactions but lack unifying concepts. Recent theoretical advances integrated both research lines proposing a sequence of stochastic and niche-based processes along successional gradients. Shifts in assembly processes are predicted to occur abruptly once abiotic and biotic factors dominate over dispersal as main driver. Considering the multidiversity composed of five organismal groups including plants, animals, and microbes, we empirically show that stochastic dispersal-dominated community assembly is replaced by environmental filters and biotic interactions after around 60 years of succession in a glacier forefield. The niche-based character of later successional processes is further supported by a decline in multi-beta-diversity. Our results may update concepts of community assembly by considering multiple taxa, help to bridge the gap between research on successions and community assembly, and provide new insights into the emergence of multidiverse and complex ecosystems.

ecology↗