Temperate Forest Plant Research Articles

Effects of Simulated Deer Browsing Intensity and Fragmentation on Regenerative Dynamics of Acer saccharum Marsh. (Sugar Maple) Plants in Temperate Forests

Effects of Simulated Deer Browsing Intensity and Fragmentation on Regenerative Dynamics of Acer saccharum Marsh. (Sugar Maple) Plants in Temperate Forests

Environmental thresholds for plant species richness of black alder (Alnus glutinosa) forests in Central Europe

The diversity of vascular plants in temperate floodplain forests varies between biogeographical regions of Europe. Our study aims to identify the key environmental drivers of plant species richness in forests dominated by black alder (Alnus glutinosa) in Central Europe with four regions: Pannonian lowland, Matricum as the southern part of the Western Carpathians, High Western Carpathians and Polish Plain. We analysed plant species richness and quantified 15 environmental characteristics (soil, climatic and landscape characteristics) in 140 vegetation plots (35 per region). We used model-based regression trees to test the influence of predictors on the richness of both native and alien species. The regression tree analysis identified eight significant variables controlling species richness in three regions and all bioregions together but found no significant predictor in Matricum. The analysis of the joint dataset indicates that native plant richness was controlled by the effects of catchment slope, soil reaction and precipitation of the warmest quarter. In contrast, the richness of alien species was influenced by the precipitation of the warmest quarter, soil phosphorous and temperature. The species richness of native plants in the High Western Carpathians was driven by soil reaction and the presence of artificial surfaces around the plots, while the richness trend in the Pannonain lowland was determined by annual temperature. Alien richness was affected by the proportion of agricultural areas in the High Western Carpathians, by the stream power index in the Polish Plain and by soil reaction in the Pannonian lowland. The explanatory power of the tree models ranged from 22 to 36%. Our results suggest that the predictability of the richness patterns is contingent upon the specific regions, which differ in the length of environmental gradients.

Unravelling the impact of soil data quality on species distribution models of temperate forest woody plants

Soil properties influence plant physiology and growth, playing a fundamental role in shaping species niches in temperate forest ecosystems. Here, we investigated the impact of soil data quality on the performance of species distribution models (SDMs) of 41 woody plant species in Swiss forests. We compared models based on measured soil properties with those based on digitally mapped soil properties on regional (Swiss Forest Soil Maps) and global scales (SoilGrids). We first calibrated topo-climatic SDMs with measured soil data and plant species presences and absences from mature temperate forest stand plots. We developed further models using the same soil predictors, but with values extracted from digital soil maps at the nearest neighbouring plots of the Swiss National Forestry Inventory. The predictive power of SDMs without soil information compared to those with soil information, as well as measured soil information vs digitally mapped, was evaluated with metrics of model performance and variable contribution. On average, models with measured and digitally mapped soil properties performed significantly better than those without soil information. SDMs based on measured and Swiss Forest Soil Maps showed higher performance, especially for species with an ‘extreme’ niche position (e.g., preference for high or low pH), compared to those using SoilGrids. Nevertheless, if no regional soil maps are available, SoilGrids should be tested for their potential to improve SDMs. Moreover, among the tested soil predictors, pH, and clay content of the topsoil layers most improved the predictive power of SDMs for forest woody plants. In conclusion, we demonstrate the value of regional soil maps for predicting the distribution of woody species across strong environmental gradients in temperate forests. The improved accuracy of SDMs and insights into drivers of distribution may support forest managers in strategies supporting e.g. biodiversity conservation, or climate adaptation planning.

An updated infrageneric classification based on phylogenomics and character evolution in Hydrangea (Hydrangeaceae)

AbstractThe genus Hydrangea s.l. (Hydrangeaceae), a favorite among gardeners, comprises more than 80 species that are important understory plants in natural temperate and subtropical forests of the Northern Hemisphere. These species are hypervariable in morphology, especially in indumentum and floral characters, warranting a thorough exploration of the complex evolutionary history of morphological characters of the genus. Ideally, this is done within a robust phylogenetic framework with extensive taxon sampling. In this study, we propose a comprehensive taxonomic reassessment of Hydrangea based on a reconstruction of its molecular phylogeny based mainly on the chloroplast genome (plastome) and the most representative taxon sampling reported to date. Phylogenomic reconstruction yielded five well‐resolved major clades and three newly recognized subclades. Inspection of the 28 characters employed in traditional taxonomic revisions revealed homoplasy in many of these traits. Our results show that characters such as growth habit, woody stem type, number of enlarged marginal sepals, style and stamen number, fruit shape, and ovary position are useful for circumscribing infrageneric divisions. Unique synapomorphies are limited. For example, herb and subshrub growth habits are associated with all the species in H. sect. Deinanthe and sect. Cardiandra, respectively. Character state combinations are proposed for distinguishing infrageneric taxa. Based on a robust phylogenetic framework, our findings suggest a complex evolutionary history of Hydrangea morphological characters. Following the criterion of monophyly and considering the morphological consistency and synapomorphy of single and combined characters to diagnose relevant lineages, we update the classification of Hydrangea into 5 subgenera and 19 sections. Our proposed taxonomic scheme, based on a robust phylogenetic framework and in‐depth character study, provides an updated perspective on the infrageneric subdivision of Hydrangea s.l.

Forest understorey flowering phenology responses to experimental warming and illumination.

Species are altering their phenology to track warming temperatures. In forests, understorey plants experience tree canopy shading resulting in light and temperature conditions, which strongly deviate from open habitats. Yet, little is known about understorey phenology responses to forest microclimates. We recorded flowering onset, peak, end and duration of 10 temperate forest understorey plant species in two mesocosm experiments to understand how phenology is affected by sub-canopy warming and how this response is modulated by illumination, which is related to canopy change. Furthermore, we investigated whether phenological sensitivities can be explained by species' characteristics, such as thermal niche. We found a mean advance of flowering onset of 7.1 d per 1°C warming, more than previously reported in studies not accounting for microclimatic buffering. Warm-adapted species exhibited greater advances. Temperature sensitivity did not differ between early- and later-flowering species. Experimental illumination did not significantly affect species' phenological temperature sensitivities, but slightly delayed flowering phenology independent from warming. Our study suggests that integrating sub-canopy temperature and light availability will help us better understand future understorey phenology responses. Climate warming together with intensifying canopy disturbances will continue to drive phenological shifts and potentially disrupt understorey communities, thereby affecting forest biodiversity and functioning.

Overexpression of the HcPT1.1 transporter in Hebeloma cylindrosporum alters the phosphorus accumulation of Pinus pinaster and the distribution of HcPT2 in ectomycorrhizae.

Ectomycorrhizal (ECM) fungi are associated with the roots of woody plants in temperate and boreal forests and help them to acquire water and nutrients, particularly phosphorus (P). However, the molecular mechanisms responsible for the transfer of P from the fungus to the plant in ectomycorrhizae are still poorly understood. In the model association between the ECM fungus Hebeloma cylindrosporum and its host plant Pinus pinaster, we have shown that the fungus, which possesses three H+:Pi symporters (HcPT1.1, HcPT1.2 and HcPT2), expresses mainly HcPT1.1 and HcPT2 in the extraradical and intraradical hyphae of ectomycorrhizae to transport P from the soil to colonized roots. The present study focuses on the role of the HcPT1.1 protein in plant P nutrition, in function of P availability. We artificially overexpressed this P transporter by fungal Agrotransformation and investigated the effect of the different lines, wild-type and transformed ones, on plant P accumulation, the distribution of HcPT1.1 and HcPT2 proteins in ectomycorrhizae by immunolocalization, and 32P efflux in an experimental system mimicking intraradical hyphae. Surprisingly, we showed that plants interacting with transgenic fungal lines overexpressing HcPT1.1 did not accumulate more P in their shoots than plants colonized with the control ones. Although the overexpression of HcPT1.1 did not affect the expression levels of the other two P transporters in pure cultures, it induced a strong reduction in HcPT2 proteins in ectomycorrhizae, particularly in intraradical hyphae, but still improved the P status of host plant shoots compared with non-mycorrhizal plants. Finally, 32P efflux from hyphae was higher in lines overexpressing HcPT1.1 than in the control ones. These results suggest that a tight regulation and/or a functional redundancy between the H+:Pi symporters of H. cylindrosporum might exist to ensure a sustainable P delivery to P. pinaster roots.

Individual response traits of understory plants vary along linked-press and compounded-pulse disturbance gradients in northern temperate and boreal forests

Community-weighted means (CWM) and functional dispersion (FDis) of response traits of woody and herbaceous understory plants in northern temperate and boreal forest communities were studied to determine how these traits respond to linked-press (i.e., climate, historic fire regimes, and silviculture systems) and compounded-pulse (i.e., harvest, site preparation, and release treatments) disturbances. We used fifth year post-harvesting disturbance data from the NEBIE plot network (NEBIE), a large-plot field experiment in northern temperate and boreal forests in Ontario, Canada. To analyze treatment effects, a randomized complete block design was assumed. Treatments were applied in a semi-operational manner to two-hectare experimental units. Individual response traits were affected by linked-press and compounded-pulse disturbances in unique ways, with logarithmic (stress-gradient hypothesis) or hump-shaped (intermediate disturbance hypothesis) patterns typically observed. Some traits (i.e., lateral spread of clones, seed weight) did not differ between disturbance types. Results suggest that all interactions between linked-press and compounded-pulse disturbances typically exert non-linear effects on CWM and FDis of individual plant response traits for both woody and herbaceous understory plants in boreal and temperate forests. Specific responses varied with trait, understory layer, and type of disturbance.

Effects of warming on seed germination of woody species in temperate secondary forests.

Seed germination, a critical stage of the plant life cycle providing a link between seeds and seedlings, is commonly temperature-dependent. The global average surface temperature is expected to rise, but little is known about the responses of seed germination of woody plants in temperate forests to warming. In the present study, dried seeds of 23 common woody species in temperate secondary forests were incubated at three temperature sequences without cold stratification and after experiencing cold stratification. We calculated five seed germination indices and the comprehensive membership function value summarized the above indicators. Compared to the control, +2 °C and +4 °C treatments without cold stratification shortened germination time by 14% and 16% and increased the germination index by 17% and 26%, respectively. For stratified seeds, +4 °C treatment increased germination percentage by 49%, and +4 °C and +2 °C treatments increased duration of germination, germination index, and shortened mean germination time by 69%, 458%, 29% and 68%, 110%, 12%, respectively. The germination of Fraxinus rhynchophylla and Larix kaempferi were most sensitive to warming without and with cold stratification, respectively. Seed germination of shrubs were the least sensitive to warming among functional types. These findings indicate warming (especially extreme warming) will enhance the seedling recruitment of temperate woody species primarily via shortening germination time, particularly for seeds undergone cold stratification. In addition, shrubs might narrow their distribution.

Does intraspecific trait variability affect understorey plant community assembly?

Increasing evidence points to the major impact of intraspecific variability in species characteristics on community assembly. Contrasting theories predict that high trait variability might either steepening dominance orders or promote diversity. Here, we try to test these predictions with understorey plants in a Polish mixed temperate forest. We focus on four important traits (leaf dry mass LDW, plant height SH, specific leaf area SLA, and number of flowers NF) of the small balsam Impatiens parviflora, the dominant species in this forest system. We relate trait variability to community species richness and abundances, as well as to soil characteristics. Trait variability was high irrespective of species richness. Contrary to theory, abundances of non-I. parviflora species significantly decreased with increasing variance in I. parviflora trait expression. Trait variability did not significantly influence species composition and was not significantly correlated with soil characteristics. Our results emphasis the need to study trait variability in terms of appropriate statistical standards as provided by the allometric variance - mean relationship. We argue that an individual based study of local trait variability might return important insights into the composition and assembly of local communities.

Wavelet Analysis Reveals Phenology Mismatch between Leaf Phenology of Temperate Forest Plants and the Siberian Roe Deer Molting under Global Warming

Global warming is deeply influencing various ecological processes, especially regarding the phenological synchronization pattern between species, but more cases around the world are needed to reveal it. We report how the forest leaf phenology and ungulate molting respond differently to climate change, and investigate whether it will result in a potential phenology mismatch. Here, we explored how climate change might alter phenological synchronization between forest leaf phenology and Siberian roe deer (Capreolus pygargus) molting in northeast China based on a camera-trapping dataset of seven consecutive years, analyzing forest leaf phenology in combination with records of Siberian roe deer molting over the same period by means of wavelet analysis. We found that the start of the growing season of forest leaf phenology was advanced, while the end of the growing season was delayed, so that the length of the growing season was prolonged. Meanwhile, the start and the end of the molting of Siberian roe deer were both advanced in spring, but in autumn, the start of molting was delayed while the end of molting was advanced. The results of wavelet analysis also suggested the time lag of synchronization fluctuated slightly from year to year between forest leaf phenology and Siberian roe deer molting, with a potential phenology mismatch in spring, indicating the effect of global warming on SRD to forest leaf phenology. Overall, our study provides new insight into the synchronization between forest leaf phenology and ungulate molting, and demonstrates feasible approaches to data collection and analysis using camera-trapping data to explore global warming issues.

中国温带典型森林植物比叶面积的空间格局及其影响因素

比叶面积（SLA）能够反映植物自身生长对策、对光能的捕获能力、对外界环境变化的适应和对可利用资源的分配策略，对植物的生境适应状况和群落的自然演替程度也起到重要的指示作用。为了深入了解温带森林植物SLA随空间变化的变异特征及其影响因素，跨越1200 km选取中国东北部12个典型温带森林（寒温带兴安落叶松林、温带红松针阔混交林和暖温带落叶阔叶栎林），通过对样地内物种进行系统性的调查，分析了植物SLA在空间上的变化规律及环境因素的影响效应。结果显示：中国温带森林植物SLA范围为2.02-99.65 m²/kg（均值为34.18 m²/kg），其中乔木SLA范围为2.02-58.74 m²/kg（均值为21.32 m²/kg），灌木SLA范围为2.88-99.65 m²/kg（均值为31.60 m²/kg），草本SLA范围为4.66-98.53 m²/kg（均值为38.75 m²/kg）。SLA在不同森林类型之间差异显著，具体表现为：温带红松针阔混交林 > 暖温带落叶阔叶栎林 > 寒温带兴安落叶松林。SLA受到气候因素和土壤因素的影响，其中随着年均降水、土壤碳氮含量的增加显著增加；随着年均温度、紫外辐射、光合有效辐射，呈先增加后降低的趋势；随着土壤碳氮比的增加显著降低。以上结果揭示了温带森林SLA的空间变异规律，可以为将来区域乃至全球尺度下植物功能性状研究提供理论支撑。;Specific leaf area (SLA) can reflect plant growth strategies, the ability to capture light energy, adaptation to changing environments, and allocation strategies of available resources. SLA critically plays an important role in indicating plant adaptation to their habitat and the degree of community succession as well. SLA is a complex of plant leaf area and weight, and is defined as the ratio of single leaf area to its dry weight. The current research on SLA in temperate forests mostly focused on the spatial variation of dominant species or just a certain tree, and the vertical variation among forests. However, the systematic investigation of the entire community was rarely carried out. This research was conducted in the northeast of China in which covered three forest types. These types were respectively cold-temperate Larix gmelinii forests, temperate broad-leaved Korean pine mixed forests and warm-temperate deciduous broad-leaved Oak forests. This study selected 12 typical temperate forests spanning 1200 km, and performed a systematic survey to explore the spatial patterns and influencing factors of plant SLA. The results showed that the SLA of China's temperate forest plants ranged from 2.02 to 99.65 m²/kg (mean, 34.18 m²/kg). Specifically, the SLA range was 2.02-58.74 m²/kg for trees (mean, 21.32 m²/kg), 2.88-99.65 m²/kg for shrubs (mean, 31.60 m²/kg), and 4.66-98.53 m²/kg for herbs (mean, 38.75 m²/kg). Plant SLA significantly differed among different forest types, with the greatest SLA in temperate broad-leaved Korean pine mixed forest, followed by warm-temperate deciduous broad-leaved Oak forest and cold-temperate Larix gmelinii forest. Significant latitudinal pattern of plant SLA was observed. As latitude increased, SLA initially increased and then decreased. SLA was found to be affected by both climatic and soil factors. SLA increased significantly with the increasing mean annual precipitation, soil carbon content, and soil nitrogen content. However, with the increase of mean annual temperature, ultraviolet radiation, and photosynthetically active radiation, SLA first increased, followed by a decline. Moreover, it decreased significantly as the soil carbon to nitrogen ratio increased. In summary, this study reveals the spatial variation of SLA in temperate forests, and it can not only provide a new perspective for the study on the response of different forest ecosystems to global change, but also provide an important theoretical basis for the development of the adaptive management of natural forests in China. Moreover, it also provides a theoretical support for future studies on plant functional traits at the regional and global scales.

Effects of canopy composition on snow depth and below-the-snow temperature regimes in the temperate secondary forest ecosystem, Northeast China

Seasonal snow cover provides a thermally stable and humid refuge for overwintering plants in temperate forests. Canopy composition changes snow processes and shapes the thermal regime. To explore canopy effects on snow depth (SD) and below-the-snow temperature, ultrasonic sensors and time-lapse infrared cameras were used to monitor SD over two winters. Three forest types with different canopy compositions [the ratio of Korean pine (Pinus koraiensis Sieb. et Zucc.) basal area, RKp] on adret (sunny) and ubac (shady) slopes, including broadleaved secondary forests, Korean pine-broadleaved mixed forests, and Korean pine plantations, were selected as sample sites. Results showed time-lapse cameras were more accurate for monitoring SD in studied forests. Increasing RKp increased the snow interception rate and reduced the peak SD, snow melting rate, and snow cover duration. 21–69% of the snowfall was intercepted by the forests, with the RKp explaining 89% of the variance in interception rates. All forest stands had the lowest interception rate for severe snow events. For each forest type, plots on ubac slopes had a lower interception rate and thicker snow cover due to the positive effects of prevailing northerly wind on snow accumulation. Inter-annual variation of snowfall affected SD, snow melting rate, and below-the-snow temperature, with smaller differences among forest stands during the below-normal snow winter (2018/2019). The subnivium established in all plots during the normal snow winter (2019/2020) with the longest maintenance in secondary forest on ubac slopes and the shortest maintenance in Korean pine forests. The temperature increment under snowpack was positively correlated with SD while negatively correlated with air temperature. Overall, the forest with fewer evergreen canopy compositions was covered with thicker snowpack for a longer duration and had a more stable and warmer temperature regime, and fewer freeze-thaw events beneath the snow, which were essential for safe overwintering of regenerated individuals.

Inter‐ and intraspecific spatial distributions, spatial segregation by dominants and emergent neutrality in understorey plants

Tradeoffs between intra and interspecific distances of individual plants determine the spatial distributions of local plant communities and small‐scale community assembly. Here we use an individual based approach and null model standardization to compare intra‐ and interspecific nearest neighbour distances of plant ramets as well as mean differences in functional trait expression to nearest heterospecifics within local communities of temperate forest understorey plants in northern Poland. We found a general tendency towards clustered intraspecific and segregated interspecific ramet distributions. Spatial distribution patterns of understorey plants differed considerably between two nearby forest sites that mainly differed in the age structure of trees. Individuals of clonal species tended to have significantly smaller intraspecific and larger interspecific nearest neighbour distances than seed dispersing species. Our results indicate a major influence of dominant plant species on the spatial distributions of subdominants. Trait expressions related to plant growth (specific leaf area and leaf mass) and reproduction (seed mass) were significantly segregated in comparison to the spatial distribution of conspecific individuals and less so in comparison to heterospecific individuals. We argue that spatially explicit analyses of plant community assembly need to consider respective distributions of important traits and that the tradeoffs of contrasting trait distributions trigger small scale plant community composition and species distributions. We present a general framework for the analysis of plant community assembly based on the spatial distributions of individual plants and functional traits.

Ericoid mycorrhizal shrubs alter the relationship between tree mycorrhizal dominance and soil carbon and nitrogen

Abstract Plant–fungal associations strongly influence forest carbon and nitrogen cycling. The prevailing framework for understanding these relationships is through the relative abundance of arbuscular (AM) versus ectomycorrhizal (EcM) trees. Ericoid mycorrhizal (ErM) shrubs are also common in forests and interactions between co‐occurring ErM shrubs and AM and EcM trees could shift soil biogeochemical responses. Here we test hypotheses that the effects of ErM shrubs on soil carbon and nitrogen either extend or are redundant with those of EcM trees. Using regional vegetation inventory data (>3,500 plot observations) we evaluated the frequency, richness and relative abundance of ErM plants in temperate forests in the eastern United States and examined their relationship with EcM plant cover. We then used surface soil (7 cm) data from 414 plots within a single forest to analyse relationships between ErM plant cover, relative EcM tree basal area and soil carbon and nitrogen concentrations while accounting for other biogeochemical controls, such as soil moisture. At both scales, we found a positive relationship between ErM and EcM plants, and the majority of ErM plants were in the shrub layer. Within the forest site, ErM plants strongly modulated tree mycorrhizal dominance effects. We found negative relationships between EcM relative basal area and soil carbon and nitrogen concentrations, but these relationships were weak to negligible in the absence of ErM plants. Both EcM relative basal area and ErM plant cover were positively associated with the soil carbon‐to‐nitrogen ratio. However, this relationship was driven by relatively lower nitrogen for EcM trees and higher carbon for ErM plants. As such, the functional effects of ErM plants on soil biogeochemistry neither extended nor were redundant with those of EcM trees. Synthesis. We found that ErM shrubs strongly influenced the relationship between tree mycorrhizal associations and soil biogeochemistry, and the effects of ErM shrubs and EcM trees on carbon and nitrogen were functionally distinct. Our findings suggest that ErM shrubs could confound interpretation of AM versus EcM tree effects in ecosystems where they co‐occur but also bolster growing calls to consider mycorrhizal functional types as variables that strongly influence forest biogeochemistry.

Disentangling the relative importance of spatio-temporal parameters and host specificity in shaping arbuscular mycorrhizal fungus communities in a temperate forest

Many woody and herbaceous plants in temperate forests cannot establish and survive in the absence of mycorrhizal associations. Most temperate forests are dominated by ectomycorrhizal woody plant species, which implies that the carrying capacity of the habitat for arbuscular mycorrhizal fungi (AMF) is relatively low and AMF could in some cases experience a limitation of propagules. Here we address how the AMF community composition varied in a small temperate forest site in Germany in relation to time, space, two plant host species, and also with regard to the degree to which plots were covered with AMF-associating woody species. The AMF communities in our study were non-random. We observed that space had a greater impact on fungal community composition than either time, mycorrhizal state of the close-by woody species, or the identity of the host plant. The identity of the host plant was the only parameter that modified AMF richness in the roots. The set of parameters which we addressed has rarely been studied together, and the resulting ranking could ease prioritizing some of them to be included in future surveys. AMF are crucial for the establishment of understory plants in temperate forests, making it desirable to further explore how they vary in time and space.

Defoliation severity is positively related to soil solution nitrogen availability and negatively related to soil nitrogen concentrations following a multi-year invasive insect irruption.

Understanding connections between ecosystem nitrogen (N) cycling and invasive insect defoliation could facilitate the prediction of disturbance impacts across a range of spatial scales. In this study we investigated relationships between ecosystem N cycling and tree defoliation during a recent 2015–18 irruption of invasive gypsy moth caterpillars (Lymantria dispar), which can cause tree stress and sometimes mortality following multiple years of defoliation. Nitrogen is a critical nutrient that limits the growth of caterpillars and plants in temperate forests. In this study, we assessed the associations among N concentrations, soil solution N availability and defoliation intensity by L. dispar at the scale of individual trees and forest plots. We measured leaf and soil N concentrations and soil solution inorganic N availability among individual red oak trees (Quercus rubra) in Amherst, MA and across a network of forest plots in Central Massachusetts. We combined these field data with estimated defoliation severity derived from Landsat imagery to assess relationships between plot-scale defoliation and ecosystem N cycling. We found that trees in soil with lower N concentrations experienced more herbivory than trees in soil with higher N concentrations. Additionally, forest plots with lower N soil were correlated with more severe L. dispar defoliation, which matched the tree-level relationship. The amount of inorganic N in soil solution was strongly positively correlated with defoliation intensity and the number of sequential years of defoliation. These results suggested that higher ecosystem N pools might promote the resistance of oak trees to L. dispar defoliation and that defoliation severity across multiple years is associated with a linear increase in soil solution inorganic N.

Safeguarding the rare woodland species Gagea spathacea: Understanding habitat requirements is not sufficient

AbstractA large proportion of temperate forest plant diversity is found in the herb layer. However, for many of its species, little is known about their autecology, which makes it difficult to assess potential threats and efficiently safeguard the diversity of understorey herbaceous communities. This also applies to Gagea spathacea (Liliaceae), a globally rare spring geophyte, which mainly occurs in deciduous forests of northern Central Europe. We investigated the causal relationships between population characteristics of G. spathacea and abiotic site conditions across different forest communities in the center of its distributional range. Leaf length (a surrogate of the species' vegetative propagation) was positively related to soil moisture and soil nitrogen. Consequently, mean leaf length was highest in moist forest communities of the alliance Alno‐Ulmion. Moreover, mean variability in leaf length was lowest in those forests, indicating a higher and more stable vegetative propagation via bulbils. We found no support for a significant relationship between leaf length and leaf density or between leaf length and flower formation. Population density varied strongly among forest sites, but was not related to soil moisture and hardly influenced by soil nitrogen. Our results suggest that soil water and nutrient supply play a vital role in determining the species' vegetative propagation, whereas the duration of habitat continuity is most likely an important determinant of population size and density. Conservation strategies therefore require a better understanding of the complex interrelationships between abiotic site conditions and the historical context‐dependency of habitats.

Downhill seed dispersal by temperate mammals: a potential threat to plant escape from global warming

Vertical seed dispersal, i.e. seed dispersal towards a higher or lower altitude, is considered a critical process for plant escape from climate change. However, studies exploring vertical seed dispersal are scarce, and thus, its direction, frequency, and mechanisms are little known. In the temperate zone, evaluating vertical seed dispersal of animal-dispersed plants fruiting in autumn and/or winter is essential considering the dominance of such plants in temperate forests. We hypothesized that their seeds are dispersed towards lower altitudes because of the downhill movement of frugivorous animals following the autumn-to-winter phenology of their food plants which proceeds from the mountain tops to the foot in the temperate zone. We evaluated the vertical seed dispersal of the autumn-fruiting wild kiwi, Actinidia arguta, which is dispersed by temperate mammals. We collected dispersed seeds from mammal faeces in the Kanto Mountains of central Japan and estimated the distance of vertical seed dispersal using the oxygen isotope ratios of the dispersed seeds. We found the intensive downhill seed dispersal of wild kiwi by all seed dispersers, except the raccoon dog (bear: mean −393.1 m; marten: −245.3 m; macaque: −98.5 m; and raccoon dog: +4.5 m). Mammals with larger home ranges dispersed seeds longer towards the foot of the mountains. Furthermore, we found that seeds produced at higher altitudes were dispersed a greater distance towards the foot of the mountains. Altitudinal gradients in autumn-to-winter plant phenology and other mountain characteristics, i.e. larger surface areas and more attractive human crops at lower altitudes compared to higher altitudes, were considered drivers of downhill seed dispersal via animal movement. Strong downhill seed dispersal by mammals suggests that populations of autumn-to-winter fruiting plants dispersed by animals may not be able to sufficiently escape from current global warming in the temperate zone.

The complete chloroplast genome sequence of Goodyera schlechtendaliana in Korea (Orchidaceae)

Goodyera schlechtendaliana is a common orchid species in East Asia, providing a case to study phylogeographic structure of understory plants in warm temperate forests. Here, we present the complete chloroplast genome of the Korean G. schlechtendaliana. Its length is 153,801 bp and it has four subregions; 82,683 bp of large-single-copy and 18,048 bp of small-single-copy regions are separated by 26,535 bp of inverted repeat regions, including 133 genes (86 protein-coding genes, eight rRNAs, and 39 tRNAs). Phylogenetic analyses suggest that the chloroplast genomic data should be useful in future phylogeographic and phylogenetic studies of Goodyera.

Endozoochory by granivorous rodents in seed dispersal of green fruits

Although the role of frugivores in seed dispersal has attracted scientific attention, it remains unclear whether granivorous rodents can act as frugivores to interact mutualistically with fruit-producing plants, especially those bearing green fruits inconspicuous to avian frugivores. In this study, we tracked fruit removal of the tara vine (Actinidia arguta (Siebold & Zucc.) Planch. Ex Miq.) and variegated kiwi vine (Actinidia kolomikta (Rupr. & Maxim.) Maxim.) in a temperate forest and presented fruits to the granivorous rodents Siberian chipmunk (Tamias sibiricus (Laxmann, 1769)), Korean field mouse (Apodemus peninsulae (Thomas, 1907)), and gray red-backed vole (Clethrionomys rufocanus (Sundevall, 1846) = Myodes rufocanus (Sundevall, 1846)) in the laboratory to answer this question. Seeds were collected from rodent feces to see the effects of gut passage on seed germination to determine the role of granivorous rodents in endozoochory of A. arguta and A. kolomikta. We presented clear evidence of endozoochory by granivorous rodents in seed dispersal of the two Actinidia species. Rodents appeared to play an alternative role in dispersing plants bearing green fruits. Moreover, we observed increased germination rates after gut ingestion by the granivorous rodents. Our study evidenced endozoochory of granivorous rodents and provided new insight into the mutualist interactions between rodents and plant species bearing fleshy fruits containing tiny seeds. We suggest future studies pay more attention to endozoochory of rodents and establish their mutualistic relationship with fruit-bearing plants in temperate forests.