Biology subjects

Mori, A. S.

Publications and source records attributed to Mori, A. S..

10 recordsLinked to original sources

bioRxiv2026

How do variable patch sizes hold higher beta diversity?

Beta diversity is a fundamental component of regional biodiversity that accumulates from compositional differences between local species assemblages. Although beta diversity is increasingly applied across spatial scales, its scale dependence remains incompletely synthesized, particularly concerning variation in spatial scale used to define alpha diversity (grain size). Using tree community data from Barro Colorado Island, we find that both additive and multiplicative beta diversity are consistently higher for unequal than equal grain divisions across different spatial extents and numbers of grains. These results can be explained by Jensen's inequality based on the concave-down relationship of alpha diversity with area that in turn increases beta diversity through the scaling relationship between alpha and gamma diversity. Combined with our additional analysis showing that this prediction is robust to more general models of species richness, including species--area and species--sampling-effort curves, these results reveal a previously unrecognized, predictable range of beta diversity variation.

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

Temperate forest heterogeneity decreases local and landscape-scale spider diversity through habitat filtering despite species turnover

O_LISpiders are key components of forest food webs, making use of the three-dimensional forest structure. Yet modern silviculture has homogenized temperate forest structure at local and landscape scales. The consequences of this homogenization for landscape-level spider diversity, however, remain largely unknown. C_LIO_LITherefore, we sampled spiders using pitfall traps across 234 patches in a large-scale, replicated field experiment at 11 paired European beech (Fagus sylvatica) forest sites in Germany. In one district per site, we experimentally diversified between-forest-patch complexity (ESBC) through canopy gap creation and deadwood enrichment and kept a second district untreated as a structurally homogeneous control. C_LIO_LIWe applied a novel meta-analytic framework to compare -, {beta}-, and {gamma}-diversity of spiders between treatment and control districts, standardized for sample coverage, along Hill numbers giving increasing weight to abundance and for taxonomic, functional, and phylogenetic diversity. To gain a deeper insight into the effects of our intervention on the processes affecting the assembly of spider communities, we investigated the response of functional-phylogenetic diversity quantified by standardized effect sizes of mean pairwise distances (SES MFPD) to our treatments. C_LIO_LIBased on 18,540 spider individuals from 206 species, treatment districts exhibited significantly lower {gamma}- and -diversity across all diversity facets and Hill numbers, particularly when focusing on rare species (q = 0). In contrast, {beta}-diversity increased in treatment districts for phylogenetic and functional diversity across all Hill numbers (q = 0, 1, 2). Although spider abundances were higher in treatment patches, functional-phylogenetic diversity decreased in gaps and ESBC districts in general, indicating a shift from limiting similarity towards habitat filtering. C_LIO_LIOur findings corroborate earlier results of high abundances but lower taxonomic and functional diversity in canopy gaps due to strong habitat filtering effects, resulting in overall lower -diversity, which cannot be compensated by increasing {beta}-diversity. Hence, the greater three-dimensional complexity of homogeneous forests supports more diverse spider metacommunities at the {gamma}-scale, particularly when controlling for sample coverage, suggesting that canopy spider diversity in temperate forests may be underestimated. Nonetheless, higher abundances in treatment districts point to increased predator pressure and greater prey availability in structurally diversified forests. C_LI

ecology↗

bioRxiv2025

A continuum of information-based temporal stability measures and their decomposition across hierarchical levels

When biodiversity-stability relationships are assessed from temporal patterns of species (or species assemblages) biomass or other key variables, ecological stability is commonly quantified as the inverse of the coefficient of variation (CV) or its square. However, just as biodiversity cannot be fully characterized by a single value, the complexity of temporal stability/invariability cannot be completely captured by one metric, especially since CV is disproportionally sensitive to large data values. Ecologists now recognize that species diversity can be fully characterized by a continuum of Hill-number-based measures parametrized by a diversity order q[≥]0, which determines the sensitivity of the measure to species abundance. Building on the intuitive concept that temporal stability can be quantified by the closeness between the data vector and the ideally maximally stable vector, we propose a continuum of information-based measures of temporal stability/invariability parameterized by an order q>0. This continuous parameter q determines the sensitivity of the measure to the magnitude of biomass or other ecosystem functions. By varying q, researchers can differentially weight small, medium, or large values in a time series, thereby disentangling their respective contributions to stability. Our framework unifies and generalizes classical measures: the case q=1 links to Shannon entropy, reflecting MacArthurs 1955 stability concept; q=2 connects to the conventional CV-based measure. Unlike these traditional metrics, our approach explicitly accounts for the number of data values (i.e., time points), adjusting for time-series-length effects to enable fair and meaningful comparisons across datasets of varying lengths. We extend the framework to hierarchical structures by developing additive and multiplicative decompositions of stability in a metacommunity (or metapopulation) into alpha and beta components. The beta component can be further used to obtain measures that quantify (a)synchrony among communities (or populations). For q=2, the resulting (a)synchrony measure provides a mathematically rigorous, CV-based metric. The proposed measures are illustrated using 22-year biomass time series data from the Jena Experiment in Germany. We developed the R package iSTAY (information-based stability measures) and online tools for computation and visualization. Our measures are adaptable to other functions beyond biomass and are applicable in both temporal and spatial contexts. Open Research StatementThe original biomass data of the Jena Experiment, covering the years 2003 to 2023, can be retrieved from https://jexis.idiv.de/ddm/Data/ShowData/624, while the 2024 data are available at https://jexis.idiv.de/ddm/Data/ShowData/695. These datasets, along with the R code used in this study, are currently accessible on Github at https://github.com/AnneChao/MS_iSTAY for review purposes and will be archived on Zenodo upon journal acceptance.

ecology↗

bioRxiv2021

Global trade-offs in tree functional traits

AO_SCPLOWBSTRACTC_SCPLOWDue to massive energetic investments in woody support structures, trees are subject to unique physiological, mechanical, and ecological pressures not experienced by herbaceous plants. When considering trait relationships across the entire plant kingdom, plant trait frameworks typically must omit traits unique to large woody species, thereby limiting our understanding of how these distinct ecological pressures shape trait relationships in trees. Here, by considering 18 functional traits--reflecting leaf economics, wood structure, tree size, reproduction, and below-ground allocation--we quantify the major axes of variation governing trait expression of trees worldwide. We show that trait variation within and across angiosperms and gymnosperms is captured by two independent processes: one reflecting tree size and competition for light, the other reflecting leaf photosynthetic capacity and nutrient economies. By exploring multidimensional relationships across clusters of traits, we further identify a representative set of seven traits which captures the majority of variation in form and function in trees: maximum tree height, stem conduit diameter, specific leaf area, seed mass, bark thickness, root depth, and wood density. Collectively, this work informs future trait-based research into the functional biogeography of trees, and contributes to our fundamental understanding of the ecological and evolutionary controls on forest biodiversity and productivity worldwide.

ecology↗

bioRxiv2020

Quaternary climate change explains global patterns of tree beta-diversity

Both historical and contemporary environmental conditions determine present biodiversity patterns, but their relative importance is not well understood. One way to disentangle their relative effects is to assess how different dimensions of beta-diversity relate to past climatic changes, i.e., taxonomic, phylogenetic and functional compositional dissimilarity, and their components generated by replacement of species, lineages and traits (turnover) and richness changes (nestedness). Here, we quantify global patterns of each of these aspects of beta-diversity among neighboring sites for angiosperm trees using the most extensive global database of tree species-distributions (43,635 species). We found that temperature change since the Last Glacial Maximum (LGM) was the major influence on both turnover and nestedness components of beta-diversity, with a negative correlation to turnover and a positive correlation to nestedness. Moreover, phylogenetic and functional nestedness was higher than expected from taxonomic beta-diversity in regions that experienced large temperature changes since the LGM. This pattern reflects relatively greater losses of phylogenetic and functional diversity in species-poor assemblages, possibly caused by phylogenetically and functionally selective species extinction and recolonization during glacial-interglacial oscillations. Our results send a strong warning that rapid anthropogenic climate change is likely to result in a long-lasting phylogenetic and functional compositional simplification, potentially impairing forest ecosystem functioning.

ecology↗

bioRxiv2020

Paleoclimate and current climate collectively shape the phylogenetic and functional diversity of trees worldwide

Trees are of vital importance for ecosystem functioning and services at local to global scales, yet we still lack a detailed overview of the global patterns of tree diversity and the underlying drivers, particularly the imprint of paleoclimate. Here, we present the high-resolution (110 km) worldwide mapping of tree species richness, functional and phylogenetic diversities based on [~]7 million quality-assessed occurrences for 46,752 tree species (80.5% of the estimated total number of tree species), and subsequent assessments of the influence of paleo-climate legacies on these patterns. All three tree diversity dimensions exhibited the expected latitudinal decline. Contemporary climate emerged as the strongest driver of all diversity patterns, with Pleistocene and deeper-time (>107 years) paleoclimate as important co-determinants, and, notably, with past cold and drought stress being linked to reduced current diversity. These findings demonstrate that tree diversity is affected by paleoclimate millions of years back in time and highlight the potential for tree diversity losses from future climate change.

ecology↗

bioRxiv2020

Reassembly of soil fungal communities under reforestation and herbivore exclusion

Soil fungi can help improve ecosystem restoration, yet our understanding of how they reassemble in degraded land is limited. Here, we studied fungal community structure using DNA metabarcoding in reforested sites following agricultural abandonment and overgrazing. Two treatments, namely reforestation using different numbers of tree species and deer exclusion, have been applied for multiple decades in the study sites. We found that local fungal richness (alpha diversity) and total fungal richness (gamma diversity) were 1.9-2.9 and 1.3-1.9 times greater, respectively, in reforested stands than in natural forests. These results were regardless of the number of tree species planted in the reforested stands. Conversely, reforested stands had a spatially homogenized community structure with relatively lower degrees of compositional dissimilarity among sites within each stand (beta diversity). These findings were attributable to lower environmental heterogeneity, stronger dispersal limitation, and a comparatively shorter time since the onset of community assembly in reforested stands. Deer exclosures had no detectable effect on fungal community structure. Overall, the agricultural legacy in fungal community structure appears to have persisted for decades, even under proactive restoration of aboveground vegetation. Direct human intervention belowground may therefore be necessary for the recovery of soil biota once altered.

ecology↗

bioRxiv2020

Half of the world's tree biodiversity is unprotected and is increasingly threatened by human activities

Although trees are key to ecosystem functioning, many forests and tree species across the globe face strong threats. Preserving areas of high biodiversity is a core priority for conservation; however, different dimensions of biodiversity and varied conservation targets make it difficult to respond effectively to this challenge. Here, we (i) identify priority areas for global tree conservation using comprehensive coverage of tree diversity based on taxonomy, phylogeny, and functional traits; and (ii) compare these findings to existing protected areas and global biodiversity conservation frameworks. We find that ca. 51% of the top-priority areas for tree biodiversity are located in current protected areas. The remaining half top-priority areas are subject to moderate to high human pressures, indicating conservation actions are needed to mitigate these human impacts. Our findings emphasize the effectiveness of using tree conservation priority areas for future global conservation planning.

ecology↗

bioRxiv2019

A universal scaling method for biodiversity-ecosystem functioning relationships

Global biodiversity is declining at rates faster than at any other point in human history. Experimental manipulations of biodiversity at small spatial scales have demonstrated that communities with fewer species consistently produce less biomass than higher diversity communities. However, understanding how the global extinction crisis is likely to impact global ecosystem functioning will require applying these local and largely experimental findings to natural systems at substantially larger spatial and temporal scales. Here we propose that we can use two simple macroecological patterns - the species area curve and the biomass-area curve - to upscale the species richness-biomass relationship. We demonstrate that at local spatial scales, each additional species will contribute more to biomass production with increasing area sampled because the species-area curve saturates and the biomass-area curve increases monotonically. We use species-area and biomass-area curves from a Minnesota grassland and a Panamanian tropical dry forest to examine the species richness - biomass relationship at three and ten sampling extents, respectively. In both datasets, the observed relationship between biodiversity and biomass production at every sampling extent was predicted from simple species-area and biomass-area relationships. These findings suggest that macroecological patterns like the species-area curve underpin the scaling of biodiversity-ecosystem functioning research and can be used to predict these relationships at the global scales where they are relevant for species loss.

ecology↗