ABSTRACT The evergreen shrub Buxus microphylla (Buxaceae; Japanese boxwood) forms distinctive ultramafic vegetation in Japan, with populations on Sugashima Island exhibiting unusually vivid crimson leaves in winter. To clarify the physiological and nutritional mechanisms underlying this coloration, we combined field monitoring with laboratory experiments to reproduce leaf reddening under controlled conditions. Field observations revealed that leaves of B. microphylla growing on ultramafic soils turned bright red each winter, whereas those from non‐ultramafic sites remained mostly green, except for slight reddening at the Mie University site. The crimson coloration coincided with a seasonal decline in leaf nitrogen (N) and chlorophyll content, suggesting that nutrient limitation enhances pigment imbalance. In laboratory assays, light exposure and sucrose addition strongly promoted chlorophyll degradation, increasing the carotenoid‐to‐chlorophyll ratio (Car/Chl) by more than 20%. Under dark conditions, both sucrose and N enhanced pigment retention. The Car/Chl ratio consistently ranked as water‐only > N‐only > multi‐nutrient media, indicating that nutrient sufficiency counteracts sugar‐induced photoinhibition and chlorophyll breakdown. These results demonstrate that leaf reddening in boxwood is not due to anthocyanin synthesis but rather to a relative enrichment of carotenoids following chlorophyll loss under photoinhibitory conditions. The combination of high irradiance, low temperature, and N deficiency on ultramafic soils promotes this imbalance, producing the intense “crimson boxwood” phenotype. Our findings highlight how nutrient limitation and photoprotection interact to shape adaptive pigmentation in plants growing on ultramafic soils.

ABSTRACT Taiwan hinoki ( Chamaecyparis obtusa Sieb. & Zucc. var. formosana (Hayata) Rehder) is one of the dominant coniferous species in subtropical montane cloud forests in Taiwan, with a high affinity for fog immersion. With the changing climate, the species is expected to face new environmental challenges. Field observations indicate that seedlings are mainly establishing on coarse woody debris (CWD) rather than forest soil, and on surfaces covered by bryophytes rather than those without. To test this “safe site” hypothesis together with vulnerability to climate change, we conducted a factorial growth‐chamber experiment. We quantified seedling performance and functional traits under varying substrate types (forest soil vs. CWD), presence/absence of bryophyte carpets, and three increasingly short‐duration drought regimes. Contrary to the prediction of the hypothesis, CWD alone resulted in poor seedling performance due to severe nutrient limitations. However, bryophyte carpets acted as a critical facilitator; the humus layer accumulated beneath bryophytes provided high concentrations of N, P, and K, allowing seedlings on CWD to achieve growth rates comparable to those on forest soil. While drought was confirmed as a significant stress factor, neither CWD nor bryophytes provided strong evidence for the expected hydrological buffering capacity. These findings suggest that the regeneration success observed on CWD in the field is driven by bryophyte nutrient facilitation rather than the wood substrate itself. Consequently, while bryophytes can ameliorate nutrient stress, the seedlings' high susceptibility to drought indicates that increasing dry intervals under future climate scenarios poses a critical threat to early‐stage regeneration.

ABSTRACT Environmental DNA (eDNA) metabarcoding is rapidly becoming an effective tool for biodiversity assessments. However, for taxa such as mesophotic and deep‐sea octocorals, which are difficult to classify based on morphological and molecular grounds and are logistically challenging to sample using conventional SCUBA diving, accurately identified and curated specimens in biological repositories remain under‐represented. This limitation reduces the availability of reliable reference sequences for eDNA detection. Mesophotic and deep‐sea octocorals are key components of mesophotic and cold‐water coral ecosystems that occur at depths > 30 m. Because these habitats are highly vulnerable to anthropogenic disturbances, the ability to monitor them effectively is imperative. This study aimed to expand the 28S rRNA reference database for mesophotic and deep‐sea octocorals in the western Pacific Ocean. A total of 269 samples were sequenced using either Sanger sequencing or low‐coverage genome skimming. Based on expert morphological identifications, the dataset comprised 52 genera spanning 24 families and two orders. Detailed metadata for all samples are provided, including DDBJ accession numbers, sampling locations, depths, collection dates, and repository information. These resources will strengthen biodiversity monitoring and support the conservation of mesophotic and cold‐water coral ecosystems. The detailed metadata and complete dataset are available in MetaCat in JaLTER at https://doi.org/10.20783/DIAS.JLE.91 .

Abstract To conserve wetland biodiversity, conservation plans must consider both local environmental factors and catchment‐scale factors that influence groundwater cycles. Spring‐dependent animals are particularly sensitive to groundwater conditions, and land‐use changes associated with urbanization can affect factors such as the temperature and stability of groundwater supply. This study aimed to examine how catchment‐scale land use influences the distribution patterns of a spring‐dependent animal. To explore this, we constructed a generalized linear model (GLM) incorporating both indirect influences from catchment land use and direct effects from local wetland environmental factors. Furthermore, to provide an example of conservation planning that considers land use, we assessed habitat suitability at the wetland level using a GLM and at the grid level using maximum entropy modeling (MaxEnt) with only landscape variables. Distribution data of Lefua echigonia , an indicator species of spring‐dependent animals, were collected through field surveys and environmental DNA analyses in 102 first‐order valleys of the Lake Inba watershed. The GLM results indicated that an index of spring water stability, the percentage of permeable surfaces in the catchment, precipitation, the period of rice paddy abandonment in the valley bottom, and valley length (representing habitat size) positively influenced the fish's presence, while summer temperature had a negative effect. The MaxEnt analysis also showed a positive effect of the percentage of permeable surfaces. Our results highlight that both land use within a catchment and catchment size, which can affect the volume and stability of spring water, are important factors for conserving suitable habitats for spring‐dependent animals.

Abstract The worldwide decline of mangroves, driven by land‐use changes, contributes to global carbon emissions. Nevertheless, there is still uncertainty surrounding the effects of mangrove deforestation on carbon emissions. Only a few studies have attempted to quantify its implications for the carbon budget, especially at the landscape level. We conducted a field assessment of carbon stock, losses or emissions associated with the conversion of these ecosystems, along with quantifying the impact of this conversion on the carbon budget using carbon sequestration rates in various types of mangrove ecosystems, including intact and varying ages of naturally regenerated mangroves within the Merlimau–Kuala Sebatu landscape. Results show that the estimated total ecosystem carbon (TEC) stock for clear‐cut sites was 149.06 ± 7.56 Mg C ha−1, whereas the TEC stock for intact sites was 280.65 ± 16.92 Mg C ha−1; however, no significant difference was observed (p > 0.05). Using a stock‐change approach, the equivalent carbon emissions are 482.93 Mg ha−1 CO2e. This is among the lowest measured C emissions from land use in the tropics. Remarkably, the landscape‐scale carbon budget remained favorable, with a net positive balance of 2835 Mg C yr−1, mainly due to the carbon sink capacity and expansion of natural regeneration of the intact mangrove site (796 Mg C yr−1). Our research identifies a deforestation threshold of 75%, at which the carbon budget approaches neutrality. These findings therefore emphasize the importance of protecting intact forests and managing regenerated mangroves sustainably, as younger mangroves help sequester carbon and reduce deforestation emissions.

Abstract Describing the population abundance of species remains a fundamental challenge in ecology, particularly in soil ecosystems. While the preferred habitats of moles—top predators in the soil food web—are well documented in open areas such as cultivated lands and grasslands, few studies have focused on mountain forests, where assessing mole abundance is complicated by thick layers of plant leaf litter and complex topography. Additionally, many monoculture conifer plantations in Japan are poorly managed, potentially resulting in compacted soil that is less suitable for moles compared to natural broad‐leaved forests. Here, we aimed to quantify the relative abundance of the lesser Japanese mole (Mogera imaizumii) in the mountain forests of Yamagata, Japan, by carefully searching for mole tunnels along 29 census routes (unpaved mountain trails) over 7 months. Although tunnels were detected on most routes (75.9%) regardless of forest type, tunnel density (tunnels/km) was lower in cedar (Cryptomeria japonica) plantations than in natural oak forests. The variation in tunnel density was positively related to earthworm biomass, highlighting the importance of earthworms as a food source. Lower earthworm biomass was associated with either higher soil hardness or higher soil moisture; however, only soil moisture tended to be higher in plantations. As cedars are typically planted in moist environments, the reduced mole abundance in these plantations may be related to the specific soil conditions of cedar plantations. These results demonstrate that mole abundance varies significantly across forest sites in response to soil environments.

Abstract There is a scarcity of research examining the influences of the addition of leaf litter from invasive plants on their own growth performance, particularly in the context of their own competitive advantage when co‐cultured with native plants. This study aimed to examine the influences of the addition of a gradient of the invasive plant Amaranthus retroflexus L. leaf litter (ARLL) on its competitive advantage. An indoor planting experiment was conducted to analyze the competitive advantage of A. retroflexus with three forms of incubation conditions, that is, A. retroflexus in the monoculture, A. tricolor L. in the monoculture, and A. retroflexus co‐cultured with A. tricolor. The addition of a low amount of ARLL was found to significantly enhance the competitive ability to obtain sunlight of both Amaranthus plants. The leaf photosynthetic capacity of A. tricolor and the growth competitiveness of A. retroflexus were found to be greater in the co‐culture than in the monoculture. The competitive ability to obtain sunlight, the relative competitive intensity, and relative dominance of A. retroflexus were found to be stronger than those of A. tricolor regardless of the amount of ARLL and the form of incubation condition. Consequently, A. retroflexus can obtain a competitive advantage over A. tricolor under the addition of a gradient of ARLL. Accordingly, the stronger competitive advantage of A. retroflexus may facilitate its invasion process.

Abstract Potentially toxic metals and metalloids (PTMs) may become a concern to plant and animal health when soil concentrations exceed toxicity limits. These limits are often exceeded in polluted environments (anthropogenic sources) and may transfer through the trophic system, from contaminated soil to plants, and thereafter to herbivores and predators. The aim of this mini review was to consider trophic transfer of PTMs in terrestrial ecosystems, focusing on arthropods as the endpoint. ScienceDirect® was used as search engine with a set of keywords. The most assessed PTMs were Cd, Pb, and Zn, and 63% of all PTMs considered in research were attributed to anthropogenic sources. Industrial or mining sites were most frequently studied, and agricultural sites the least. Brassica was the most studied plant genus as the main extractor of PTMs from the soil as they are easy growing food plants known to take up PTMs. Research mostly focused on primary consumers, with Coleoptera being the most investigated arthropod order, probably because of the diversity of the order and its common occurrence worldwide. Most research was conducted in Europe, while South America and Africa only contributed 6.8% and 2.6%, respectively. The majority of the investigated articles (61%) assessed trophic transfer. From those, only 24% directly measured PTM transfer with experimental trials and included only one trophic level, that is, primary consumers, while 7% of research directly measured PTM transfer across multiple trophic levels (primary and secondary consumers).