Biology subjects

Kenta, T.

Publications and source records attributed to Kenta, T..

8 recordsLinked to original sources

bioRxiv2025

Generalist flowers recover rapidly in grassland restoration: The importance of floral traits in community reassembly

Community assembly process, through biotic and abiotic filtering of species traits, is crucial for understanding the recovery of biodiversity and ecosystem function in restored ecosystems. While previous studies have highlighted very slow recovery of pollination networks in ecological restoration, the reassembly process of plant communities focusing on floral traits that influence pollination networks remains underexplored. We hypothesised that plant species with flowers that allow visits by various pollinators (generalist flowers) would recover more easily than those with flowers which limit pollinators (specialist flowers) during grassland restoration. We investigated floral trait assemblages, interaction patterns with pollinators, and pollination success for each floral trait (floral tube and colour) across 28 pollination networks. We examined their temporal change patterns within restored grasslands (2-75 years old) and compared them with reference old grasslands (>165 years old). Our results revealed that generalist (open/shallow and white/yellow) flowers have recovered rapidly, interacting with many pollinator species with similar traits in the early stages of restoration. In contrast, specialist (long-tubed and blue/purple) flowers exhibited more delayed recovery due to low pollination success, taking approximately 75 years for the recovery to the levels of reference old grasslands. Importantly, we found that functional specialisation was crucial for the recovery of these specialist flowers. Corresponding to temporal changes in floral trait assemblages, pollinator composition has shifted from dipteran dominance to a greater abundance of long-tongued bees, with interaction patterns of each trait group approaching those of old grasslands. Our findings underscore the pivotal role of floral trait reassembly in influencing temporal changes in pollinator community, network structure, and pollination function during grassland restoration. By integrating trait-based framework, this study provides novel insights into the co-reassembly process of plants and pollinators in restored ecosystems.

ecology↗

bioRxiv2024

Temporal continuity of habitat strengthens covariation between plant and arbuscular mycorrhizal fungal communities

Old grassland is considered one of the most biodiverse terrestrial ecosystems. The habitat temporal continuity may promote the accumulation of host species and symbiont arbuscular mycorrhizal fungi (AMF) diversity and strengthen symbiont interactions. We tested the hypothesis that covariation between AMF and plant communities is stronger in old grasslands. We compared the relationship between AMF and plant communities in forests and in new and old semi-natural grasslands in Japan. DNA was extracted from bulk roots collected at each site and from roots of Miscanthus sinensis at each grassland site. AMF operational taxonomic unit was characterized on the basis of small subunit rRNA gene sequences. Old grasslands harboured the highest diversity of AMF among vegetation types. The AMF compositions were significantly related to those of plant species. The covariation of plant-AMF communities was stronger in old grasslands than in new grasslands. Individuals of M. sinensis were found to share AMF with bulk roots comprising different species. This suggests that AMF form a common mycorrhizal network among several coexisting plants of different species. Increasing AMF diversity in the shared rhizosphere has been proposed to lead to more efficient utilization of soil nutrients and to increase overall benefits of plant-AMF facilitation.

ecology↗

bioRxiv2024

Long-lasting negative effects of past forestation on grassland pollination networks and their function

O_LIGrasslands are facing a rapid decline worldwide. Among the primary threats to these ecosystems are changes in land use, such as land abandonment and forestation, which promote forest vegetation in detriment of grassland plant diversity. To support the conservation and restoration of grasslands, it is key to understand what ecological processes limit the recovery of their biodiversity and functions after perturbations. However, we still know little about the legacy effects of forestation on the ecological mechanisms involved in the recovery of grasslands, especially concerning long-lasting impacts on plant-pollinator interaction networks and plant reproduction. C_LIO_LIHere, we aim to fill this gap of knowledge by comparing the plant and pollinator diversity, the degree of network generalization, the pollination success and pollen limitation of native plant species in 30 plant-pollinator networks of old-growth and restored grasslands of different ages since recovery (from 2 to 84 years). We hypothesized that past forestation would exert long-lasting legacy negative effects on plant richness and plant-pollinator networks, increasing pollen limitation for native plants, thereby delaying community recovery in restored grasslands. C_LIO_LIResults showed that restored grasslands exhibited significantly lower plant richness, less specialized (more generalized) interaction networks, lower pollination success and pollen-limited seed reproduction of native plants compared to old-growth grasslands. Meanwhile, the degree of network specialization and pollination success gradually increased with time after grassland restoration initiated. Overall, network generalization, which was caused by low plant richness, reduced pollination and reproduction success in native grassland plants, and degraded pollination networks and functions could recover in restored grasslands with continuous management. These findings imply that plant diversity restoration was slow because of the negative feedbacks associated with low plant richness and consequently, generalized plant-pollinator interaction networks, which diminished native plant reproduction in restored grasslands. C_LIO_LISynthesis and applications Our findings suggest that the recovery of specialized plant-pollinator networks by enhancing plant diversity is essential for restoring pollination function. For quicker grassland restoration, it may be effective to facilitate the establishment of highly specialized pollination networks by seeding or planting diverse native plants collected from neighbouring areas while avoiding genetic contamination. C_LI

ecology↗

bioRxiv2022

PlantServation: time-series phenotyping using machine learning revealed seasonal pigment fluctuation in diploid and polyploid Arabidopsis

Long-term field monitoring of leaf pigment content is informative for understanding plant responses to environments distinct from regulated chambers, but is impractical by conventional destructive measurements. We developed PlantServation, a method incorporating robust image-acquisition hardware and deep learning-based software to analyze field images, where the plant shape, color, and background vary over months. We estimated the anthocyanin contents of small individuals of four Arabidopsis species using color information and verified the results experimentally. We obtained >4 million plant images over three field seasons to study anthocyanin fluctuations. We found significant effects of past radiation, coldness, and precipitation on the anthocyanin content in the field. The synthetic allopolyploid A. kamchatica recapitulated the fluctuations of natural polyploids by integrating diploid responses. The data support a long-standing hypothesis stating that allopolyploids can inherit and combine the traits of progenitors. PlantServation pipeline facilitates the study of plant responses to complex environments termed "in natura."

plant biology↗

bioRxiv2022

Negative legacy effects of past forest use on plant diversity in semi-natural grasslands on ski slopes

Over the past century, grassland and forest ecosystems globally have been heavily influenced by land use changes driven by diverse socioeconomic activities. Ski resorts are a modern land-use type associated with biodiversity loss in mountain ecosystems worldwide. Below the treeline, by contrast, some ski slopes have been shown to provide suboptimal semi-natural habitats for native grassland plants and animals, depending on specific construction and management practices. We compared environmental factors and grassland vegetation between two types of ski slopes in central Japan with different land-use histories: slopes constructed on old pastures (pasture slopes) and slopes constructed by clearing secondary forests or Larix kaempferi plantations established on abandoned pastures during the 1940s-1990s (forest slopes). We examined the effects of land use history and machine grading as well as other environmental factors on ski slope vegetation, including total species richness and the richness of native, endangered, and exotic plants, using a total of 108 plots of 2 m x 10 m. Compared to pasture slopes, forest slopes exhibited significantly lower richness of total plants and native grassland species, including endangered species. Forest slopes were more graded than pasture slopes, resulting in lower native and higher exotic grassland species richness. A significantly lower duration of direct sunlight on forest slopes than on pasture slopes possibly decreased endangered species diversity. The lower species richness on forest slopes may be partly caused by seed dispersal limitations. Our findings demonstrate that ski slopes have good potential to support numerous native grassland plant species, including endangered species, but this potential is significantly and negatively affected by forest use history and concomitant environmental changes. The conservation of semi-natural conditions on pasture slopes as habitats for native grassland species can be promoted through the maintenance of annual mowing practices, avoidance of machine grading, and wider ski courses. NomenclatureYonekura & Kajita (2003) BG Plants: index of Japanese names and scientific names (YList; http://ylist.info/index.html)

plant biology↗

bioRxiv2020

The effects of temporal continuities of grasslands on the diversity and species composition of plants

Semi-natural grasslands are ecosystems rich in biodiversity. However, their decline has been reported worldwide, and identification of grasslands with high conservation priority is urgently required. Recently, an increasing number of studies have reported that past vegetation history affects current biological communities. To evaluate whether the temporal continuity of grasslands promotes biodiversity, and thus can be an indicator of conservation priority, we studied vascular plant communities in old (160- 1000s years) and new (52-70 years after deforestation) grasslands, as well as in forests, of Sugadaira Highland in central Japan. The number of plant species was highest in old grasslands, followed by new grasslands and forests. This pattern was much clearer in the number of grassland-dependent native and grassland-dependent endangered species, indicating the role of old grasslands as refugia for those species. The species composition differed between old and new grasslands. New grasslands had species compositions in between those of old grasslands and forests, suggesting that the plant community in new grasslands retains the influence of past forestation for more than 52 years after deforestation. Eleven indicator species were detected in old grasslands, but none in new grasslands, suggesting the uniqueness of the plant community in old grasslands. We conclude that the temporal continuity of grasslands increases plant diversity and can be an indicator of grasslands with high conservation priority.

ecology↗

bioRxiv2019

Experimental and field data support habitat expansion of the allopolyploid Arabidopsis kamchatica owing to parental legacy of heavy metal hyperaccumulation

Little empirical evidence is available whether allopolyploid species combine or merge adaptations of parental species. The allopolyploid species Arabidopsis kamchatica is a natural hybrid of the diploid parents A. halleri, a heavy metal hyperaccumulator, and A. lyrata, a non-hyperaccumulating species. Zinc and cadmium were measured in native soils and leaf tissues in natural populations, and in hydroponic cultures of A. kamchatica and A. halleri. Pyrosequencing was used to estimate homeolog expression ratios. Soils from human modified sites showed significantly higher Zn concentrations than non-modified sites. Leaf samples of A. kamchatica collected from 40 field localities had > 1,000 {micro}g g-1 Zn in over half of the populations, with significantly higher amounts of Zn concentrations in plants from human modified sites. In addition, serpentine soils were found in two populations. Most genotypes accumulated >3000 {micro}g g-1 of Zn in hydroponic culture with high variability among them. Genes involved in hyperaccumulation showed a bias in the halleri-derived homeolog. A. kamchatica has retained constitutive hyperaccumulation ability inherited from A. halleri. Our field and experimental data provides a compelling example in which the inheritance of genetic toolkits for soil adaptations likely contributed to the habitat expansion of an allopolyploid species.

evolutionary biology↗

bioRxiv2018

Factors influencing leaf- and root-associated communities of bacteria and fungi across 33 plant orders in a grassland

In terrestrial ecosystems, plants interact with diverse taxonomic groups of bacteria and fungi in the phyllosphere and rhizosphere. Although recent studies based on high-throughput DNA sequencing have drastically increased our understanding of plant-associated microbiomes, we still have limited knowledge of how plant species in a species-rich community differ in their leaf and root microbiome compositions. In a cool-temperate semi-natural grassland in Japan, we compared leaf- and root-associated microbiomes across 138 plant species belonging to 33 plant orders. Based on the whole-microbiome inventory data, we analyzed how sampling season as well as the taxonomy, nativeness (native or alien), lifeform (herbaceous or woody), and mycorrhizal type of host plants could contribute to variation in microbiome compositions among co-occurring plant species. The data also allowed us to explore prokaryote and fungal lineages showing preferences for specific host characteristics. The list of microbial taxa showing significant host preferences involved those potentially having some impacts on survival, growth, or environmental resistance of host plants. Overall, this study provides a platform for understanding how plant and microbial communities are linked with each other at the ecosystem level.

ecology↗