Biology subjects

Kadoya, T.

Publications and source records attributed to Kadoya, T..

4 recordsLinked to original sources

bioRxiv2022

Higher-order dissimilarity in biodiversity: Identifying dissimilarities of spatial or temporal dissimilarity structures

O_LIElucidating biodiversity patterns and their background processes is critical in biodiversity science. Dissimilarity, which is calculated based on multivariate biological quantities, is a major component of biodiversity. As spatial and temporal biodiversity information availability increases, the scope of dissimilarity studies has been expanded to cover various levels and types of spatio-temporal biodiversity facets (e.g., gene, community, and ecosystem function), and diverse pairwise dissimilarity indices have been developed. However, further development of the dissimilarity concept is required in comparative studies on spatio-temporal structures of biodiversity compositional patterns, such as those exploring commonalities of biogeographical boundaries among taxa, compared to the conventional ones to consider higher dimensions of dissimilarity: dissimilarity of dissimilarity structures. C_LIO_LIThis study proposes a novel and general concept, high-order dissimilarity (HOD), for quantitatively evaluating the dissimilarities of spatial or temporal dissimilarity structures among different datasets, proposes specific implementations of HOD as operational indices, and illustrates the potential resolution of scientific and practical questions through HOD. C_LIO_LIWe further demonstrate the advantages of the HOD concept by applying it to actual patterns, such as long-term and/or large-spatial hypothetical monitoring datasets. C_LIO_LIOur conceptual framework on HOD extends the existing framework of biodiversity science and is versatile, with many potential applications in acquiring more valuable information from ever-increasing biodiversity data. C_LI

ecology↗

bioRxiv2021

Severe disturbance overflows the stabilizing buffer of variable biotic interactions

Recent studies have revealed that biotic interactions in ecological communities vary over time, possibly mediating community responses to anthropogenic disturbances. This study investigated the heterogeneity of such variability within a real community and its impact on population stability in the face of pesticide application, particularly focusing on density-dependence of the interaction effect. Using outdoor mesocosms with a freshwater community, we found considerable heterogeneity in density-dependent interaction variability among links in the same community. This variability mediated the stability of recipient populations, with negative density-dependent interaction variability stabilizing whereas positive density-dependence and density-independent interaction variability destabilizing populations. Unexpectedly, the mean interaction strength, which is typically considered crucial for stability, had no significant effect, suggesting that how organisms interact on average is insufficient to predict the ecological impacts of pesticides. Our findings emphasize the multifaceted role of interaction variability in predicting the ecological consequences of anthropogenic disturbances such as pesticide application.

ecology↗

bioRxiv2021

Ecosystem size and complexity dictate riverine biodiversity

Larger ecosystems support more species; this ubiquitous pattern is the foundation of current conservation schemes. However, many ecosystems possess a complex spatial structure that cannot be represented by area, and the role of such complexity in scaling biodiversity is largely unknown. Here, we use theory and extensive fish community data from two distinct geographic regions (Japan and United States) to show that ecosystem size and complexity dictate riverine biodiversity. We found that larger and more branched complex river networks harbored greater species richness due to increased space and environmental heterogeneity. The complexity effect was comparable to the size effect, and this pattern has emerged regardless of ecological contexts. The dual control of biodiversity may be a pervasive feature that has far-reaching implications for biodiversity conservation. One sentence summaryThis study provides the first evidence that ecosystem size and complexity play comparable roles in regulating biodiversity.

ecology↗

bioRxiv2021

Multispecies site occupancy modeling and study design for spatially replicated environmental DNA metabarcoding

O_LIEnvironmental DNA (eDNA) metabarcoding has become widely applied to gauge biodiversity in a noninvasive and cost-efficient manner. The detection of species using eDNA metabarcoding is, however, imperfect owing to various factors that can cause false negatives in the inherent multi-stage workflow. C_LIO_LIImperfect detection in the multi-stage workflow of eDNA metabarcoding also raises an issue of study design: namely, how available resources should be allocated among the different stages to optimize survey efficiency. C_LIO_LIHere, we propose a variant of the multispecies site occupancy model for eDNA metabar-coding studies where samples are collected at multiple sites within a region of interest. This model describes the variation in sequence reads, the unique output of the high-throughput sequencers, in terms of the hierarchical workflow of eDNA metabarcoding and interspecific heterogeneity, allowing the decomposition of the sources of variation in the detectability of species throughout the different stages of the workflow. We also introduced a Bayesian decision analysis framework to identify the study design that optimizes the efficiency of species detection with a limited budget. C_LIO_LIAn application of the model to freshwater fish communities in the Lake Kasumigaura watershed, in Japan, highlighted a remarkable inhomogeneity in the detectability of species, indicating a potential risk of the biased detection of specific species. Species with lower site occupancy probabilities tended to be difficult to detect as they had lower capture probabilities and lower dominance of the sequences. The expected abundance of sequence reads was predicted to vary by up to 23.5 times between species. C_LIO_LIAn analysis of the study design suggested that ensuring multiple within-site replications of the environmental samples is preferred in order to achieve better species detection efficiency, provided that a throughput of tens of thousands of sequence reads was secured. C_LIO_LIThe proposed framework makes the application of eDNA metabarcoding more error-tolerant, allowing ecologists to monitor ecological communities more efficiently. C_LI

ecology↗