Ecological Research最新文献

Mast seeding in Norway spruce (Picea abies) provides an abundant food source for rodents, such as bank voles (Clethrionomys glareolus). While seed quantity effects are well known, intraspecific variation in seed palatability is not. In this study, I tested whether voles show preferences for spruce seeds from different batches of seeds (sampled from different mast years). In controlled trials, voles did not show significant preferences for seeds from different years, suggesting limited variation in seed characteristics detectable by voles. The results support that variations in the small spruce seeds may be primarily a quantitative burst of food (i.e., during mast seeding) rather than a qualitative variation that influences foraging behavior. Understanding these dynamics contributes to our knowledge of resource-driven rodent ecology and the role of mast seeding on granivore behavior.

Deer affect their habitats in various ways. Many previous studies on the ecological functions of deer have investigated the impact of herbivory on vegetation but have rarely focused on other functions. In this study, we evaluated the seed dispersal function of the sika deer (Cervus nippon yesoensis) in Hokkaido Island, examining the process from foraging to germination. We (1) surveyed the composition of seeds dispersed by wild deer, (2) measured seed recovery rate and gut passage time by feeding trials using three fleshy-fruited trees (Vitis coignetiae, Actinidia arguta, and Rosa rugosa), (3) conducted germination tests using defecated intact seeds, and (4) estimated seed dispersal distance and its seasonal changes using GPS movement data. In total, 73 seedlings of at least 10 species emerged from 181 fecal samples, each weighing ~1 g. The proportion of intact seeds after gut passage varied greatly with plant species and among trials (0.0%–55.0%). The germination rate of intact defecated seeds was similar to (R. rugosa and V. coignetiae) or higher (A. arguta) than that of manually washed seeds. The average seed dispersal distances during the resident period were 594 m for V. coignetiae and 610 m for A. arguta. The average seed dispersal distances during the migration period increased to 3140 m for V. coignetiae and 3617 m for A. arguta, and sometimes exceeded 18,000 m. These findings highlight that sika deer can disperse seeds over long distances, thus contributing to gene flow between distant populations and range expansion to suitable habitats.

Recent developments in Unmanned Aerial Vehicles (UAVs) and Light Detection and Ranging (LiDAR) technology have enhanced the ability to capture precise three-dimensional forest information at a lower cost. This article reports four types of high-resolution digital datasets derived from UAV-LiDAR measurements and associated fieldwork. The dataset includes 5 cm resolution Digital Terrain Models (DTMs) and Canopy Height Models (CHMs), ortho-mosaic photos with sub-2.7 cm resolution, and 4328 tree crown polygons with information on 151 species, stem girth at breast height, and canopy height. Data were collected from 22 approximately 1-ha long-term monitoring plots across Japan, spanning major climate zones from subtropical to subarctic. These plots encompass evergreen conifer, broadleaf and conifer mixed, deciduous broadleaf, and evergreen broadleaf forests. UAV surveys were conducted from May 2022 to October 2023. Based on these data, we also report basic profiles of these natural forests: a median slope of 22.2° (ranging from 2.5° to 35.0° across sites), median canopy height of 19.2 m (10.5–25.2 m), median maximum canopy height of 29.4 m (17.6–39.8 m), median gap ratios of 1.7% (0–10.7%) and 7.7% (0–28.9%) depending on gap definitions, and median crown area of 42.9 m² (10.7–80.2 m²) for canopy trees. This dataset is the first publicly available collection of forest structure and individual tree crown information for Japanese natural forests. We hope this dataset will be useful for a wide range of studies and analyses, from site-specific case studies to global-scale meta-analyses. The metadata is available in MetaCat in JaLTER at https://jalter.diasjp.net/data/ERDP-2025-04.

Solar radiation (SR) dynamics significantly influence plant growth, development, and ecosystems, serving as a primary energy source and an essential environmental signal. Plants sense SR through photoreceptors, with the ratios between specific wavelength ranges being particularly significant. Therefore, we refer to these as critical wavelength ratios (CWRs). The diffuse fraction of solar radiation (DF) is a key factor shaping light quality and distribution within the plant canopy. To evaluate the potential effects of DF and CWRs on plants in an outdoor environment, we analyzed 1 year of SR spectral data collected using a rotating shadow-band spectroradiometer in Fukuoka, Japan. Cloudy or partly cloudy skies dominated throughout the year. The ratios of UV-A/UV-B, red (R)/blue (B), and R/green (G) increased in winter and decreased in summer. In contrast, the ratios of photosynthetically active radiation (PAR)/global solar radiation (GSR), UV/GSR, UV/PAR, B/G, R/far-red, and UV-B/B increased during summer and decreased in winter. Most CWRs were significantly correlated with the DF. The clearness index (CI) exhibited a strong correlation with DF and CWRs. A synergistic effect of air mass (AM), atmospheric water vapor pressure (VP), and CI on specific CWRs was revealed. Future climate change-driven increases in VP and DF, coupled with reductions in CI, are expected to trigger complex changes in plant growth and flowering by altering light signals and enhancing photosynthesis through diffuse light fertilization. Integrating VP, AM, DF, and CI dynamics into climate models could enhance predictions of atmospheric, ecological, and plant physiological responses.

Accurate information on agricultural productivity is crucial to addressing the challenges faced by agriculture, including pest threats and climate change. Crop-growing calendars represent a vital source of information for understanding and managing agroecosystems and for enhancing agricultural productivity. This information is also essential for studying the relationship between crop growth stages and pest activity patterns, which is crucial for developing effective pest management strategies. This study systematically digitized the Japanese government's publicly available paper-based statistical data on crop-growing calendars for grain crops, vegetables, and fruit trees across the country. The paper provides a detailed account of the contents of the paper-based statistical data, the digitization procedure, the method for creating the database, and the database structure. This work represents a significant step toward making crop-growing calendar data more accessible and useful for agricultural research and applications. The detailed Metadata and complete data set are available in MetaCat in JaLTER at https://jalter.diasjp.net/data/ERDP-2025-03.

Understanding the factors that control the structure of soil microbial communities is crucial to predict the responses of terrestrial ecosystems to global change. Microbial biomass, composition, and physiological and nutritional states are known to be influenced by abiotic and biotic factors. However, how they vary and respond collectively to abiotic and biotic factors, particularly in forest ecosystems at the landscape scale, remains unclear. This study applied statistical models to explain variations in soil microbial properties from 18 forest sites covering a wide range of annual temperatures, soil properties, stand ages, and plant leaf traits in the Japanese archipelago. Soil microbial properties were evaluated using phospholipid fatty acid (PLFA) analysis. Our results show that fungal PLFA concentration was mainly explained by soil carbon (C) concentration, whereas bacterial and total PLFA concentrations were predominantly determined by soil nitrogen (N) concentration. The ratio of fungal to bacterial PLFA was best explained by the soil C:N ratio. Most variations in microbial composition and physiological and nutritional states were mainly explained by the mean annual temperature and soil pH. Community-weighted means of plant traits, particularly leaf dry matter content (LDMC), also contributed to explaining the variation in bacterial and total PLFA concentrations as well as physiological and nutritional states indicative of temperature and nutritional stress. These results suggest that abiotic factors and plant traits can shape the microbial community structure in forest soils, and that global warming may affect the soil system by altering the physiological and nutritional states of soil microbes in the Japanese archipelago.

This special issue is a partial compilation of research papers from the 10th International Conference on Acid Deposition “ACID RAIN 2020” conference held in Niigata, Japan in April 2023, focusing on ecosystem responses to air pollution. The Acid Rain Conference series began in 1975, initially addressing the harmful effects of acid deposition on ecosystems. Over time, the research focus evolved from simple acid rain issues to effects of excess nitrogen deposition and saturation in the 1980s, and then to ecosystem recovery studies in the 1990s. Current research examines interactions with climate change and air pollution in developing countries. The special issue contains 11 papers: eight on long-term ecosystem responses, two on plants' role in reducing air pollution, and one technical note on soil sampling in biogeochemical monitoring. The long-term studies, from Japan and Norway, show different regional responses to acid deposition. Japanese forests demonstrate higher acid buffering capacity than Northern European ones, partly due to the composition of volcanic soil. Nordic papers focus on modeling tools, MAGIC (Model of Acidification of Groundwater In Catchments), which has been improved over time to simulate the combined effect of acid deposition and climate change impacts. It is significant that exactly half a century after the first conference, this collection of contemporary papers will be published in Ecological Research. This is because findings from research on biogeochemical cycles in ecosystems related to acid rain should be widely shared among the ecological community, and through this, a variety of audiences should be informed.

The assessment of taxonomic diversity (TD) and functional diversity (FD) in natural gradients, including elevation, has grown over the past two decades, but is still relatively little studied. By studying amphibians in the Brazilian forest areas, this research aims to address critical knowledge gaps about biodiversity distribution, while highlighting the need to conserve this fragile and unique hotspot. Herein, we assessed whether and how environmental predictors explain taxonomic and functional alpha and beta diversities of frogs in a Brazilian tropical forest. Elevation significantly and negatively affected TD and FD, with a monotonic linear decrease of both variables with increasing altitude. We did not detect a significant influence of habitat amount (as measured by proportion of forest vegetation cover) on either TD or FD, probably because we observed minimal variation in habitat amount along the elevational gradient. We found a significant influence of elevation on taxonomic and functional dissimilarity values, predominantly explained by the turnover rather than the nestedness component. Our results highlight the importance of functional traits for understanding frog distribution patterns along environmental gradients. Community-level studies on tropical frogs, especially montane species vulnerable to environmental and climatic impacts, remain limited, posing challenges for conservation and management efforts. The high turnover of species composition and functional roles emphasizes the importance of conserving the entire mountain habitat, including the upper elevations.

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.