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This study aimed to explore the interrelationships among plant species, their ecological niches, and community stability by establishing and investigating long-term biodiversity monitoring plots. Understanding the succession patterns of these communities can provide a foundation for biodiversity conservation, forest resource management, and vegetation restoration in forest parks. A 1 hm² plot was selected within the broad-leaved forest in the Xin’anjiang Forest Park for dynamic monitoring. Based on their importance values, the study focused on the top 13 dominant woody species. Ecological niche widths (BS, BL) and niche overlap indices(Oik) were calculated. Statistical methods including variance ratio, Chi-square test χ2, Pearson’s coefficient of correlation, and Spearman’s rank-order correlation coefficient were used to analyze the relationship between species niche overlap indices and species associations. The study found no significant correlation between the ranking of importance values and niche breadths. Schima superba presented the highest importance value, followed by Quercus glauca, Castanopsis sclerophylla, and Lithocarpus glabra. These four species demonstrated a competitive edge in the community’ s resource dynamics, displaying a high degree of niche convergence among the dominant species. The collective linkage of the 13 dominant species demonstrated a marked positive correlation. The χ2 test results indicated strong relative independence among species, with only one species pair showing significant linkage, indicating loose connectivity. The Pearson correlation coefficient presented a significant level of 24. 4%, while the Spearman rank correlation coefficient showed that only 28. 2% of species pairs had significant linkage. The niche overlap index was positively correlated with species connectivity. In summary, the overall community was determined to be in a stable state and is currently progressing toward the mid-to-late stage of positive succession. It is recommended that appropriate thinning of denser stands, particularly of Castanopsis sclerophylla and Cunninghamia lanceolata, be conducted to promote the formation of a high-quality forest community while strictly protecting the current forest. [ABSTRACT FROM AUTHOR]

[Objective] To explore how phosphorus input regulates the effects of atmospheric nitrogen deposition on soil aggregate organic carbon content and the relationship between carbon and phosphorus. [Methods] A long-term monitoring test platform for nutrient addition was established in evergreen broad-leaved forest soil for 6 years (2015—2021), including 4 treatments: Control [P0+N0, P 0 kg/(hm2·a)+N 0 kg/(hm2·a)], nitrogen addition [P0+N100, P 0 kg/(hm2·a)+N 100 kg/(hm2·a)], phosphorus input [P50+N0, P 50 kg/(hm2·a)+N 0 kg/(hm2·a)] and nitrogen and phosphorus were simultaneously input (P50+N100, P 50 kg/(hm2·a)+N 100 kg/(hm2·a)], and each treatment was repeated 3 times, and a total of 12 plots were obtained. 0—10 cm soil samples were collected from the sample site in August 2021 to determine the basic physical and chemical properties, soil particle size distribution, phosphorus components of soil aggregates of different particle sizes, and organic carbon (SOC) content. [Results] (1) Under P0 treatment, nitrogen addition significantly increased the proportion of large aggregates, decreased the clay and powder contents, and increased the SOC content in each aggregate particle size. Nitrogen addition significantly decreased and increased the content of labile phosphorus (LP) and residual phosphorus (RP) in aggregate clay and powder, respectively. (2) Under P50 treatment, nitrogen addition significantly increased the geometric mean diameter (GMD) of soil aggregates, but had no significant effects on phosphorus components and SOC contents in aggregates of different particle sizes. (3) Under P0 treatment, soil aggregate SOC was positively correlated with refractory phosphorus. There was no significant correlation between SOC of soil aggregates and functional phosphorus components under P50 treatment. It was concluded that under P0 treatment, nitrogen addition could increase soil organic carbon retention by increasing the refractory phosphorus in soil aggregate clay and powder particle size of evergreen broad-leaved forest. Under P50 treatment, the effect of nitrogen addition on organic carbon in each particle size may be regulated by biological factors and has nothing to do with the availability of phosphorus. [Conclusion] The effect of nitrogen deposition on the internal relationship of carbon and phosphorus in soil aggregates in evergreen broad-leaved forests was regulated by phosphorus. The results of this study provide data supported for forest soil carbon cycling in response to global climate change.

Quercus myrsinifolia is one of the dominant species in the evergreen broad-leaf forest on the southern slope of Shennongjia. The study of spatial distribution pattern and spatial correlation of Q. myrsinifolia population will help to understand population development and potential ecological processes; as well as the structure and biodiversity maintenance mechanism of evergreen broad-leaf forests at the northern edge of the subtropics. Based on forest dynamic monitoring data from one 1 hm2 permanent plot on the southern slope of Shennongjia' we employed pair correlation functions g( r) and marked correlation functions to analyze the diameter structure of the Q. myrsinifolia population; spatial distribution patterns at different diameter classes; and intraspecific and interspecific spatial associations. The results showed that diameter structure of Q. myrsinifolia population exhibited an inverted ' J ' - shaped distribution; suggesting a healthy regeneration status and belonging to a growing population type. The spatial distribution showed a decreasing trend in aggregation with increasing diameter. Positive correlations among individuals strengthened with closer diameter classes; while weakening with larger diameter differences. Interspecific spatial associations showed an increasing correlation of Q. myrsinifolia with understory dominant species with increasing spatial scales; but no correlation was observed with canopy-dominant species. Our results suggested that the spatial pattern of Q. myrsinifolia populations on the southern slope of Shennongjia was mainly influenced by habitat filtering ' seed dispersal limitation; and intraspecific and interspecific competition. Furthermore; the adaptive strategies of Q. myrsinifolia varied when they coexisted with different species. [ABSTRACT FROM AUTHOR]

Existing land surface models still have large error in the simulation of surface albedo. At present, introducing the influence of meteorological factors into the albedo parameterization scheme is an effective way to improve the albedo simulation. However, the improvement of the vegetation canopy surface albedo parameterization scheme is still insufficient. Therefore, based on the radiation and meteorological observation data during 1 November 2015–30 April 2018 from a land‐atmosphere interaction observation tower in a typical secondary evergreen broadleaved forest in Southern China, this study firstly analyzed the influencing factors of canopy surface albedo. It was found that the solar elevation angle and air relative humidity are two key factors influencing the canopy surface albedo, and the impact of the solar elevation angle on canopy surface albedo is not exactly the same on diurnal and seasonal scales. Then, two new canopy surface albedo parameterization schemes of additive form and multiplicative form were proposed and introduced into CLM5 model for single point simulation. Results show that the adoption of newly developed canopy surface albedo parameterization schemes can improve the simulation of diurnal and seasonal variations of albedo and reduce the overestimation of the simulation of near‐infrared radiation albedo and visible radiation albedo in the CLM5 model, then significantly reduce the root mean square errors of reflected solar radiation and net radiation simulation. Plain Language Summary: Surface albedo is an important factor affecting the heat exchange between land and atmosphere, and is critical for weather forecasting and regional climate modeling. At present, even in some complex land surface models, the canopy surface albedo parameterization scheme only considers the variation of leaf and stem index and the cosine of the solar zenith angle over time but does not take into account the effect of meteorological factors. In this study, two newly developed canopy albedo schemes that take into account the effects of solar elevation angle and air relative humidity were developed, and then introduced into the CLM5 model for single point simulation. The results show that the new canopy albedo scheme can indeed improve the simulation skills of the reflected solar radiation. The results emphasize the important influence of meteorological factors on the surface albedo, and the findings may provide a base to further develop and improve the CLM5 model. Key Points: Two new canopy surface albedo schemes considering the influence of solar elevation angle and air relative humidity are proposedThe new canopy surface albedo schemes can reduce the canopy surface albedo of evergreen broad‐leaved forest overestimated by CLM5 model [ABSTRACT FROM AUTHOR]

Forest conversion is a common management practice in forestry, yet the effects of forest conversion on the transformation of phosphorus (P) fractions remain unclear. This work aims at assessing the changes in soil P fractions, including total P (TP), available P (AP), inorganic P (Pi), organic P (Po) and microbial biomass P (MBP) after natural conversion of Chinese fir plantations (CFP) to evergreen broad-leaved forests (EBLF) in subtropical China. Results showed the contents of soil TP and Po were not affected by the forest conversion, but soil AP and MBP concentrations and their proportion significantly increased with forest conversion from CFP to EBLF. The contents of soil P fractions were significantly accumulated in the topsoil (0–20 cm) in the studied forests. Additionally, soil P contents were higher in the winter–spring seasons than in the summer–fall seasons during the period of study. Soil AP content was positively correlated with TP, Po, Pi, labile organophosphorus (LOP), moderate labile organophosphorus (MLOP), moderate resistant organophosphorus (MROP), aluminum–bound P (Al–P), iron–bound P (Fe–P) and MBP contents in EBLF, while the content of soil AP was positively related to Po, LOP, MLOP, Al–P, Fe–P and MBP contents in CFP. Path analysis showed that the most important factor in affecting soil P availability was Po (LOP and HROP) in EBLF stands and was Al–P in CFP stands. Our study suggested that management practices in conserving soil Pi (especially in Al–P) in the CFP and in increasing Po inputs in the EBLF would improve soil P availability in subtropical forests. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Below‐ground plastic responses to soil nutrient 'hot‐spots' form a key nutrient foraging strategy of plants coexisting in natural ecosystems. However, it is unclear how plant species differ in these below‐ground plastic responses and how they covary.Plastic responses to soil phosphorus (P)‐rich patches of absorptive root, mycorrhizal, and exudation traits of 17 coexisting arbuscular mycorrhizal (AM) tree species in a subtropical evergreen broad‐leaved forest were investigated using a root bag method.There was considerable variation and heterogeneity in species‐specific responses to P‐rich patches. Negative log response ratios usually occurred for high‐cost traits and positive log response ratios for low‐cost traits. There were trade‐offs in the plastic responses between root acid phosphatase activity and extraradical hyphal length, which were unaffected by phylogeny, and between root acid phosphatase activity and specific root length. Thicker‐rooted species responded to P‐rich patches more through root exudation plasticity than mycorrhizal plasticity. Thinner‐rooted species relied more on mycorrhizal plasticity.Synthesis. Our results revealed diverse P foraging strategies comprising different combinations of plastic adjustments in absorptive root, mycorrhizal, and exudation traits among coexisting AM tree species, which suggest the potential for complementary exploitation of different soil P sources. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ecology & Rural Environment is the property of Journal of Ecology & Rural Environment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Lucidophyllous (evergreen broad-leaved) forests are the dominant forests in human-dominated subtropical/warm-temperate regions in East Asia. Biometric-based estimates of net primary production (NPP) were conducted in a secondary lucidophyllous forest on Mt. Kinka (35°26′ N, 136°47′ E) near the northern limit of their distribution in central Japan for three years, including the masting event. The forest stand mainly consists of Castanopsis cuspidata (Thunb.) Schottky and Cleyera japonica Thunb. in the canopy and subtree layers, respectively. In 2018, the total NPP of the masting year was 14.53 ± 2.03 ton ha−1 yr−1, including woody NPP (above: 2.63 ± 0.35 ton ha−1 yr−1; below: 0.57 ± 0.08 ton ha−1 yr−1), foliage NPP (4.07 ± 0.23 ton ha−1 yr−1), reproductive NPP (4.81 ± 0.77 ton ha−1 yr−1), and fine root production (Pfr) (2.46 ± 1.84 ton ha−1 yr−1). Pfr and belowground production comprised 16.9% and 20.9%, respectively, of the total NPP. The nut production of C. cuspidata in 2018 (4.31 ± 0.75 ton ha−1 yr−1) was significantly higher than that in 2017 (0.77 ± 0.13 ton ha−1 yr−1) and 2019 (0.23 ± 0.06 ton ha−1 yr−1). No significant change was observed for the three years of foliage NPP and total NPP without Pfr. However, the woody NPP in 2018 (3.20 ± 0.43) was lower than in 2017 (5.37 ± 0.33 ton ha−1 yr−1) and 2019 (4.71 ± 0.38 ton ha−1 yr−1). This suggests that nut production in the masting years compensated by decreasing woody production in the Castanopsis forest. [ABSTRACT FROM AUTHOR]

Bryophytes play an important role in biogeochemical cycles and functions in forest ecosystems. Global climate changes have led to the population decline of bryophytes; however, the effects of bryophyte loss on the soil organic carbon stock and microbial dynamic remain poorly understood. Here, bryophytes were artificially removed to simulate the loss of bryophytes in two forests in Southwest China, i.e., evergreen broad-leaved forest and temperate coniferous forest. Soil physicochemical properties, microorganisms, and soil organic carbon stocks were analyzed and factors regulating soil organic carbon stocks were explored. Results showed that bryophyte removal significantly decreased soil organic carbon in the coniferous forest but had a negligible effect on the evergreen broad-leaved forest. Bryophyte removal had an insignificant effect on soil properties and microbial PLFAs except that soil nitrogen significantly increased in the 0–10 cm layer in the evergreen broad-leaved forest, while soil temperature and bulk density increased in the coniferous forest in the 0–10 and 10–20 soil layers, respectively. Soil organic carbon stocks increased by 14.06% in the evergreen forest and decreased by 14.39% in the coniferous forest. In the evergreen forest, most soil properties and microorganisms contributed to the change of soil organic carbon stocks, however, only soil organic carbon and depth had significant effects in the coniferous forest. Our findings suggest that soil physiochemical properties and microorganisms regulated the different responses of soil organic carbon stocks after bryophyte removal in the two forests. More research is needed to better understand the effects of understory plants on soil organic carbon stocks in various forest ecosystems. [ABSTRACT FROM AUTHOR]

The recalcitrant understory fern layer is an important ecological filter for seedling regeneration, yet how the fern layer influences seedling regeneration dynamics remains unclear. Here we transplanted 576 seedlings of four dominant tree species, Castanopsis fargesii, Lithocarpus glaber, Schima superba and Hovenia acerba, to the treatments of Diplopterygium glaucum retention and removal under an evergreen broad-leaved forest in eastern China. We monitored the survival, growth and biomass data of these seedlings for 28 months, and then used generalized linear mixed models to evaluate the treatment effects on seedling survival, growth, biomass and rootshoot ratio. Our results showed that fern retention significantly inhibited the seedling establishment of all four species. During the seedling development stage, the seedling relative growth rate of L. glaber decreased under fern retention, which was not the case for the other three species. Root-shoot ratio of C. fargesii and L. glaber increased significantly under fern retention. Our findings provide new evidence of the filtering effect of a recalcitrant fern understory. Notably, we observed that the response of tree seedlings to the recalcitrant fern understory was more sensitive in the establishment stage. Finally, our work highlights that the filtering effect of the recalcitrant fern understory changes depending on the regeneration stages, and that shadetolerant species, C. fargesii and L. glaber were even more affected by fern disturbed habitats, suggesting that effective management should attempt to curb forest fern outbreaks, thus unblocking forest recruitment. [ABSTRACT FROM AUTHOR]

Plant functional traits are rarely used in tree species classification, and the impact of vertical canopy positions on collecting samples for classification also remains unclear. We aim to explore the feasibility and effectiveness of leaf traits in classification, as well as to detect the effect of vertical position on classification accuracy. This work will deepen our understanding of the ecological mechanism of natural forest structure and succession from new perspectives. In this study, we collected foliar samples from three canopy layers (upper, middle and lower) and measured their spectra, as well as eight well-known leaf traits. We used a leaf hyperspectral reflectance (LHR) dataset, leaf functional traits (LFT) dataset and LFT + LHR dataset to classify six dominant tree species in a subtropical evergreen broad-leaved forest. Our results showed that the LFT + LHR dataset achieved the highest classification results (overall accuracy (OA) = 77.65% and Kappa = 0.73), followed by the LFT dataset (OA = 74.26% and Kappa = 0.69) and the LHR dataset (OA = 69.06% and Kappa = 0.63). Along the vertical canopy, the OA and Kappa increased from the lower to the upper layers, and the combination data of the three canopy layers achieved the highest accuracy. For the individual tree species, the shade-tolerant species (including Machilus chinensis, Cryptocarya chinensis and Cryptocarya concinna) produced higher accuracies than the light-demanding species (including Schima superba and Castanopsis chinensis). Our results provide an approach for enhancing tree species recognition from the plant physiology and biochemistry perspective and emphasize the importance of vertical direction in forest community research.

Masting is a common reproductive strategy regulating seedling regeneration in many perennial plant species. The evolutionary origins and functional benefits of masting have been explained by well‐supported hypotheses relating to economies of scale of seed production. Nevertheless, our understanding of the potential costs of masting for the plant seed‐to‐seedling transitions remains limited.We tracked the seed fate and documented changes in the seed spatial distribution patterns during the seed‐to‐seedling transition process of Castanopsis fargesii, a dominant species of subtropical evergreen broad‐leaved forests in China under natural conditions for more than 6 years.Masting resulted in a high proportion of seeds escaping predation by vertebrates and rodents, supporting the predator satiation hypothesis. However, it increased the pre‐dispersal seed predation by insects, and decreased the seed germination rate due to a negative effect on seed mass. This resulted in seed‐to‐seedling transition rates during mast years to be roughly half as much as during non‐mast years. In addition, masting negatively affected the spatial rearrangement of seeds, resulting in a spatial aggregative distribution pattern of newly germinated seedlings. The combined negative effects of smaller seeds and spatially aggregated seedlings reduced the survival rate of newly germinated seedlings at seedling establishment stage.Synthesis. Considering the whole seed‐to‐established seedling transition process, the benefits of masting on seedling recruitment due to the effective seed predator situation by vertebrates and rodents were decreased by the additional costs on seed mass, seed germination, seed spatial arrangement and seedling establishment. Our results highlight the importance of considering both the positive and negative effects of masting at each stage of the seed‐to‐seedling transition. Inferences based on seed predation and recruitment of newly germinated seedlings alone would lead to an overly optimistic conclusion about the benefits of masting. [ABSTRACT FROM AUTHOR]

Quercus myrsinifolia is one of the dominant species in the evergreen broad-leaf forest on the southern slope of Shennongjia. The study of spatial distribution pattern and spatial correlation of Q. myrsinifolia population will help to understand population development and potential ecological processes, as well as the structure and biodiversity maintenance mechanism of evergreen broad-leaf forests at the northern edge of the subtropics. Based on forest dynamic monitoring data from one 1 hm 2 permanent plot on the southern slope of Shennongjia, we employed pair correlation functions g ( r ) and marked correlation functions to analyze the diameter structure of the Q. myrsinifolia population, spatial distribution patterns at different diameter classes, and intraspecific and interspecific spatial associations. The results showed that diameter structure of Q. myrsinifolia population exhibited an inverted 'J'-shaped distribution, suggesting a healthy regeneration status and belonging to a growing population type. The spatial distribution showed a decreasing trend in aggregation with increasing diameter. Positive correlations among individuals strengthened with closer diameter classes, while weakening with larger diameter differences. Interspecific spatial associations showed an increasing correlation of Q. myrsinifolia with understory dominant species with increasing spatial scales, but no correlation was observed with canopy-dominant species. Our results suggested that the spatial pattern of Q. myrsinifolia populations on the southern slope of Shennongjia was mainly influenced by habitat filtering, seed dispersal limitation, and intraspecific and interspecific competition. Furthermore, the adaptive strategies of Q. myrsinifolia varied when they coexisted with different species.

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Copyright of Journal of Ecology & Rural Environment is the property of Journal of Ecology & Rural Environment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Forest Research is the property of Forest Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• Primary forest conversion reduced soil microbial network complexity. • Higher soil bacterial and lower fungal diversity in cropland than primary forest. • RR value: dominant & keystone taxa > network parameters > α diversity indices. • Microbial indices mainly related to reduced soil C lability and N availability. Soil microbial communities play essential roles in degraded soil ecosystems. The "emergent trait" indices (e.g., microbial biomass C and N, and enzyme activity) and specific soil microbiota associations have been intensively studied, but the responses of soil microbial composition and network complexities to land-use changes remain unclear. Using amplicon sequencing of 16S rRNA genes and internal transcribed spacer (ITS) regions, we assessed the response ratio of soil microbial genomic diversity, community structure, and network parameters to primary evergreen broadleaved forest (control) conversion to conifer plantations, orchards, sloping tillage, and paddy fields. Agricultural lands had a higher soil bacterial and lower fungal diversity than primary forest. Overall, primary forest conversion reduced microbial network complexity, except in the sloping tillage. Moreover, land-use changes shifted the microbial community composition by either decreasing or increasing the relative abundance of dominant and putative keystone associations. The mean response ratio (indicator response percentage to primary forest conversion) of the microbial index to the land-use change varied depending on the soil microbial alpha diversity, network topological parameters, and dominant and putative keystone associations. Alterations in soil microbial diversity, composition, and network complexity were related to reduced soil resource availability following land-use change. Our study suggested that primary forest conversion to agricultural lands did not always negatively influences soil microbial diversity, composition, network complexity, and putative keystone associations. In addition, specific soil microbial associations showed highly sensitive to land-use change. [ABSTRACT FROM AUTHOR]

Yunnan's biodiversity is under considerable pressure and subtropical evergreen broad-leaved forests in this area have become increasingly fragmented through agriculture, logging, planting of economic plants, mining activities and changing environment. The aims of the study are to investigate climate change-induced changes of subtropical evergreen broad-leaved forests in Yunnan and identify areas of current species richness centers for conservation preparation. Stacked species distribution models were created to generate ensemble forecasting of species distributions, alpha diversity and beta diversity for Yunnan's subtropical evergreen broad-leaved forests in both current and future climate scenarios. Under stacked species distribution models in rapid climate changes scenarios, changes of water-energy dynamics may possibly reduce beta diversity and increase alpha diversity. This point provides insight for future conservation of evergreen broad-leaved forest in Yunnan, highlighting the need to fully consider the problem of vegetation homogenization caused by transformation of water-energy dynamics.

Although organisms can alter dynamics of elements in ecosystems via physiological results, the effects of tree species on ecosystem nutrient dynamics are highly uncertain. A four-fold variation in the calcium concentrations of streams, soils and leaf litters were caused by the planting of Cryptomeria japonica in south-central Japan. In this study, we examined how the calcium dynamics were affected by the planting of C. japonica through strontium isotope analysis. We predicted the planting of C. japonica would result in the calcium concentration increasing because of the significant dissolution of calcium from bedrock. In a forest ecosystem, calcium is usually derived from precipitation and bedrock weathering, and their relative contributions can be estimated using a strontium isotope mixing model. Therefore, we collected stream water, litter, soil, precipitation and bedrock samples from 17 sites in catchments dominated by C. japonica plantation or evergreen broad-leaved forest; after collection, we analyzed the sample chemical compositions and strontium isotope ratios. The calcium concentrations in the stream water and the water-soluble calcium in the soil were significantly higher at sites dominated by C. japonica than at broad-leaved forest sites. Strontium isotope analysis indicated that there was more calcium from the bedrock present in stream water at sites dominated by C. japonica than in stream water at broad-leaved forest sites. Our results showed that watershed-scale dynamics of calcium and other cations can be altered by the type of vegetation in a catchment due to the effects of vegetation on the supply of calcium from bedrock. [ABSTRACT FROM AUTHOR]

Forest ecosystems are an integral component of the global carbon cycle as they take up and release large amounts of C over short time periods (C flux) or accumulate it over longer time periods (C stock). However, there remains uncertainty about whether and in which direction C fluxes and in particular C stocks may differ between forests of high versus low species richness. Based on a comprehensive dataset derived from field-based measurements, we tested the effect of species richness (3-20 tree species) and stand age (22-116 years) on six compartments of above- and below-ground C stocks and four components of C fluxes in subtropical forests in southeast China. Across forest stands, total C stock was 149+12 Mg ha-1 with richness explaining 28.5% and age explaining 29.4% of variation in this measure. Species-rich stands had higher C stocks and fluxes than stands with low richness; and, in addition, old stands had higher C stocks than young ones. Overall, for each additional tree species, the total C stock increased by 6.4%. Our results provide comprehensive evidence for diversity-mediated above- and below-ground C sequestration in species-rich subtropical forests in southeast China. Therefore, afforestation policies in this region and elsewhere should consider a change from the current focus on monocultures to multi-species plantations to increase C fixation and thus slow increasing atmospheric CO2 concentrations and global warming. [ABSTRACT FROM AUTHOR]

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Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Precipitation changes such as more frequent drought and altered precipitation seasonality may impose substantial impacts on the structure and functioning of forest ecosystems. A better understanding of tree responses to precipitation changes can provide fundamental information for the conservation and management of forests under future climate regimes. We conducted a 2-year seasonal rainfall redistribution experiment to assess the responses of tree transpiration and growth to manipulated precipitation changes in a subtropical evergreen broad-leaved forest. Three precipitation treatments were administered including a drier dry season and wetter wet season treatment (DD), an extended dry season and wetter wet season treatment (ED), and an ambient control treatment, with the total amount of annual rainfall being kept the same among the three treatments. Our results showed that the DD and ED treatments reduced daily transpiration of Schima superba by 8-16 and 13-25%, respectively. The ED treatment also reduced the DBH increment of larger S. superba individuals. In contrast, neither treatment showed obvious effects on the transpiration and DBH increment of another dominant species Michelia macclurei. However, the transpiration of both species showed clear inter-annual differences between the 2 years with contrasting annual rainfall (2094 vs 1582 mm). S. superba had a lower transpiration-to-precipitation ratio (T/P) compared to M. macclurei and showed decreased sensitivities to total solar radiation and vapor pressure deficit under the DD and ED treatments. These results indicate the deep-rooted S. superba may be suppressed with a lower ability to obtain water and assimilate carbon compared to the shallow-rooted M. macclurei under the precipitation seasonality changes, which could potentially cause shifts in species dominance within the forest community. [ABSTRACT FROM AUTHOR]

Purpose: Evergreen broad-leaved forest ecosystems are common in east China, where they are both ecologically and economically important. However, nitrogen (N) addition over many years has had a detrimental effect on these ecosystems. The objective of this research was to evaluate the effect of 4 years of N addition on microbial communities in an evergreen broad-leaved forest in southern Anhui, China. Materials and methods: Allochthonous N in the form of aqueous NHNO and phosphorus (P) in the form of Ca(HPO)·HO were applied at three doses with a control (CK, stream water only without fertilizer): low-N (50 kg N ha year), high-N (100 kg N ha year) and high-N+P (100 kg N ha year + 50 kg P ha year). Quantitative PCR analysis of microbial community size and Illumina platform-based sequencing analysis of the V3-V4 16S rRNA gene region were performed to characterize soil bacterial community abundance, structure, and diversity. Results and discussion: Bacterial diversity was increased in low-N and high-N treatments and decreased in the high-N+P treatment, but α-diversity indices were not significantly affected by N additions. Proteobacteria, Acidobacteria, and Actinobacteria were the predominant phyla in all treatments, and the relative abundance of different genera varied among treatments. Only soil pH ( P = 0.051) showed a weak correlation with the bacterial community in CK and low-N treatment. Conclusions: The composition of the bacterial community and the abundance of different phyla were significantly altered by N addition. The results of the present study indicate that soil bacterial communities in subtropical evergreen broad-leaved forest are, to a certain extent, resilient to changes derived from N additions. [ABSTRACT FROM AUTHOR]

Questions Mosaics of evergreen and deciduous trees that are characteristic of evergreen broad-leaved forests ( EBLF) are thought to arise from habitat heterogeneity, but empirical evidence for this is limited. We test this assertion asking: (1) whether environmental heterogeneity explains the distribution of deciduous and evergreen trees; (2) which are the most important environmental variables; and (3) does their importance change with scale? Location Tiantong National Forest Park, Ningbo, Zhejiang, China. Methods We used data from a 20-ha individual-mapped EBLF in spatial point-pattern analyses testing the scale of aggregation within, and segregation between, the two life forms. We used a heterogeneous Poisson process model to remove the effects of environmental heterogeneity, predicting segregation would disappear if the mosaic was due to habitat heterogeneity alone. Finally, we tested the relative importance of theoretically important environmental variables using multivariate regression trees at three spatial scales (10, 20 and 50 m grid cells). Results We found evergreen and deciduous trees were aggregated at scales below 125 m and 60 m, respectively, and mutually exclusive at scales <120 m. Evidence of any spatial segregation between the life forms was removed at all scales after controlling for environmental heterogeneity. Only soil phosphorus concentrations contributed to spatial patterns at all scales, with values >0.27-0.30 g·kg−1 favouring deciduous species. Conclusions Our study is consistent with habitat heterogeneity creating the observed mosaics of evergreen and deciduous tree species, but micro-habitat heterogeneity contributed even at scales <20 m. Soil phosphorus availability appears to be the major environmental variable maintaining these mosaic patterns at hillslope scales in EBLF. [ABSTRACT FROM AUTHOR]

In this paper, secondary forest of Pinus massoniana, coniferous-broad-leaved mixed forest and broad-leaved evergreen forest were taken as research objects, to explore carbon reserve of arbor layer and its spatial distribution characteristics. At different succession stages, the sequence of organic carbon content in each organ was secondary forest of P. massoniana > coniferous-broad-leaved mixed forest > broad-leaved evergreen forest. Carbon reserve of arbor layer was the highest in broad-leaved evergreen forest, which was 129.34 t/hm², followed by coniferous-broad-leaved mixed forest (95.83 t/hm²), and the minimum was 85.27 t/hm² in secondary forest of P. massoniana. In each stand type, the sequence of carbon reserve of each organ in arbor layer was trunk > root > branch > leaf > bark. Carbon reserve of arbor layer mainly concentrated in trunk, and the proportion to carbon reserve of arbor layer declined from secondary forest of P. massoniana to broad-leaved evergreen forest, while it had increasing relationship in root. In secondary forest of P. massoniana, coniferous-broad-leaved mixed forest and broad-leaved evergreen forest, individual with the diameter more than 20 cm accounted for the majority of carbon reserve in the arbor layer. [ABSTRACT FROM AUTHOR]

In this paper, the Pinus massoniana forest in the early stage of succession, the coniferous broad-leaved mixed forest in the middle stage of succession, and the evergreen broad-leaved forest in the late stage of succession were studied, and the biomass and its spatial distribution characteristics of the tree layer in different succession stages of the ecosystem were discussed. The results showed that the biomass of the arbor layer was the highest in the evergreen broad-leaved forest, which was 292.51 t/hm², followed by the coniferous and broad-leaved mixed forest, which was 206.87 t/hm², and the Pinus massoniana forest, which was 171.76 t/hm². The biomass of trunks accounted for the largest proportion in the total biomass of the arbor layer, which reduced from the Pinus massoniana forest to the evergreen broad-leaved forest. The proportion of the biomass of roots in the total biomass of the arbor layer increased from the Pinus massoniana forest to the evergreen broad-leaved forest. The biomass of the diameter class above 20 cm in the Pinus massoniana forest, the coniferous and broad-leaved mixed forest and the evergreen broad-leaved forest accounted for a large proportion of total biomass. [ABSTRACT FROM AUTHOR]

Temperature lapse rate (TLR), measured as the degree of temperature change along an altitudinal gradient, is a key indicator of multiple ecological processes of mountain systems. Although many studies have examined temperature changes of open air or near-surface along altitudes, we know little about altitudinal variations of soil temperature, which play an important role in regulating growth and reproduction of organisms, as well as ecosystem nutrient cycling. Based on temperature data of near-surface (15 cm above ground) and soil layers (8 cm below ground) from 12 sampling sites of subtropical forest along an altitudinal gradient (300-1300 m) in Jiangxi Guan-shan National Nature Reserve from September 2018 to August 2021, we calculated the lapse rates of mean, maximum, and minimum temperatures, as well as accumulated temperatures by using simple linear regression for both near-surface and soil temperature. The seasonal dynamics of aforementioned variables were also evaluated. The results showed that there were large differences among mean, maximum, and minimum lapse rates for annual near-surface temperature, which were 0.38, 0.31 and 0.51 ℃·(100 m) -1 , respectively. But little variation was documented for soil temperature which were 0.40, 0.38 and 0.42 ℃·(100 m) -1 , respectively. The seasonal variations of temperature lapse rates for near-surface and soil layers were minor except for minimum temperature. The lapse rates of minimum temperature were deeper in spring and winter for near-surface and in spring and autumn for soil layers. For growing degree days (GDD), the accumulated temperature under both layers were negatively correlated with altitude, and the lapse rates of ≥5 ℃ were 163 ℃·d·(100 m) -1 for near-surface and 179 ℃·d·(100 m) -1 for soil. The ≥5 ℃ GDD in soil were about 15 days longer than that in near-surface at the same altitude. The results showed inconsistent patterns of altitudinal variations between near-surface and soil temperature. Soil temperature and its lapse rates had minor seasonal variations compared with the near-surface counterparts, which was related to the strong buffering capacity of soil.

To better understand how plant-frugivore interactions change in relation to forest stand development, we investigated the abundance and species composition of frugivorous bird assemblages, and their fruit removal over several years in three warm-temperate forest stands. All stands were located in an urban forested area of western Japan, and each was at a different developmental stage: a secondary deciduous broad-leaved forest stand (DB), an evergreen broad-leaved forest stand where an evergreen oak became dominant recently (EB-I), and a well-developed evergreen broad-leaved forest stand (EB-II). Although the species richness and Shannon diversity indices of frugivorous birds did not vary among the three stands, the abundance of birds was almost always greatest in the EB-II stand, lowest in the DB stand, and intermediate in the EB-I stand. Generalized linear mixed model analyses using data on monthly fruit availability and the number of frugivorous birds observed in censuses showed that forest stand differences had a significant effect on the abundance of frugivorous birds, whereas fruit availability had no significant positive influence on bird abundance. Fruit removal was most intensive in the EB-II stand, where both fruit and bird abundance were highest, followed by the EB-I stand, where bird abundance was intermediate but fruit abundance was lowest. Our study demonstrates that increasing structural complexity during forest stand development likely had positive effects on the abundance of frugivorous birds, which in turn influenced fruit removal in this urban forested area. Hence, a positive feedback mechanism of plant-bird interactions would exist for the development of forest stands. [ABSTRACT FROM AUTHOR]

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In order to test whether density dependence influences community diversity, a combination of manipulative experimentation and plot surveys were done using Cryptocarya concinna, a dominant species in subtropical evergreen forest. Twelve pairs of 1 m2 seedling plots were built around 12 adults, and plots were treated monthly with either a fungicide or a control. The surviving proportion of C. concinna seedlings at different stages was calculated, and an analysis was conducted on the impact of fungicide on seedling survival and species richness. Correlation between relative abundance and community evenness at different ages was analyzed using plot surveys. The results showed that fungicide treatment decreased species richness of the seedling community by promoting the recruitment of common species. Furthermore, census of a 25 m radius around adult C. concinna trees confirmed that the density of saplings increased with distance from adults. Relative abundance of C. concinna decreased with increasing age, and decreasing C. concinna dominance resulted in an increase in community evenness. To avoid the appearance of a single optimum population, the dominance of C. concinna decreased with age via density dependence, and subsequently improved community species diversity. [ABSTRACT FROM AUTHOR]

Subsoils store over 50% of the total soil organic carbon (SOC) in terrestrial ecosystems, but the stability of this fraction of SOC and the contributions of the associated soil microbes to C dynamics remain unclear. A natural evergreen broad-leaved forest and a Chinese fir plantation converted from natural forest in Fujian Province, China, were used to test if differences in soil C decomposability and soil microbial characteristics between topsoil (0–10 cm) and subsoil (40–60 cm) were associated with the prevalence of microbes expressing a characteristic growth strategy (r-versus K-strategies). A combined approach, including modified Michaelis-Menten kinetics, substrate-induced respiration, soil C decomposition, soil basal respiration measurements, and phospholipid fatty acid (PLFA) analysis was used. Compared with topsoil, the subsoil had 3.6 and 1.6 times higher concentrations of readily decomposable C substrate (as glucose equivalents) estimated in terms of Michaelis-Menten kinetics, and 2.7 and 2.8 times faster mineralization per unit SOC, respectively, under the natural and plantation forests. Soil microbes in the subsoil tended to be r-strategist-dominated in both forests, characterized by higher maximum rate of soil respiration and half-saturation constant, higher maximal specific growth rate, higher relative abundance of Gram-negative bacteria, and higher metabolic quotient, the latter indicating smaller C use efficiency. In contrast, soil microbes in the topsoil tended to be K-strategist-dominated. Soil microbial communities shifted from K-strategy to r-strategy in the topsoil of Chinese fir plantation, reflecting lower microbial C use efficiencies, compared with natural forest. It is concluded that a substantial pool of easily decomposable C accumulated in subsoils of these two subtropical forests, a product partly of r-strategists replacing K-strategy microbes. These findings improve our understanding of the mechanisms regulating C dynamics between topsoil and subsoil and have implications for the effects of forest conversion on soil C storage. [ABSTRACT FROM AUTHOR]

Ｄｏｍｉｎａｎｔ ｐｌａｎｔ ｐｏｐｕｌａｔｉｏｎｓ ｈａｖｅ ｇｒｅａｔ ａｂｉｌｉｔｙ ｔｏ ａｄａｐｔ ｔｏ ｔｈｅ ｅｎｖｉｒｏｎｍｅｎｔ ａｎｄ ｕｓｅ ｒｅｓｏｕｒｃｅｓ, ａｎｄ ｔｈｅｙ ｐｌａｙ ａ ｄｅｃｉｓｉｖｅ ｒｏｌｅ ｉｎ ｔｈｅ ｃｏｍｍｕｎｉｔｙ ｓｔｒｕｃｔｕｒｅ ａｎｄ ｆｕｎｃｔｉｏｎ. Ｗｈａｔ'ｓ ｍｏｒｅ, ｔｈｅ ｓｐｅｃｉｅｓ ｎｉｃｈｅ ｃｈａｒａｃｔｅｒｉｓｔｉｃ ｒｅｆｌｅｃｔｓ ｔｈｅ ｕｔｉｌｉｚａｔｉｏｎ ｏｆ ｅｎｖｉｒｏｎｍｅｎｔａｌ ｒｅｓｏｕｒｃｅｓ ｆｒｏｍ ａ ｐｅｒｓｐｅｃｔｉｖｅ. Ｉｎ ｏｒｄｅｒ ｔｏ ｅｘｐｌｏｒｅ ｔｈｅ ｒｅｌａｔｉｏｎｓｈｉｐ, ｐｏｓｉｔｉｏｎ ａｎｄ ｆｕｎｃｔｉｏｎ ｏｆ ｅａｃｈ ｄｏｍｉｎａｎｔ ｓｐｅｃｉｅｓ ｐｏｐｕｌａｔｉｏｎ ｉｎ ａｎ ｅｖｅｒｇｒｅｅｎ ｂｒｏａｄ-ｌｅａｖｅｄ ｆｏｒｅｓｔ ｏｆ Ｂａｉｓｈａｎｚｕ, ｎｉｎｅ ｓｕｂｐｌｏｔｓ ｏｆ ２０ ｍ×２０ ｍ ｒｅｇｕｌａｒｌｙ ｆｒｏｍ ｔｈｅ ５ ｈｍ２(２５０ ｍ×２００ ｍ) ｐｌｏｔ ｗｈｉｃｈ ｅｓｔａｂｌｉｓｈｅｄ ｉｎ ２００３ ｗｅｒｅ ｓｅｌｅｃｔｅｄ, ｗｈｅｒｅ ａｌｌ ｔｒｅｅｓ ｗｉｔｈ ＤＢＨ≥１ ｃｍ ｗｅｒｅ ｔａｇｇｅｄ, ｍｅａｓｕｒｅｄ, ａｎｄ ｉｄｅｎｔｉｆｉｅｄ ｔｏ ｓｐｅｃｉｅｓ. Ｔｈｅ ｎｉｃｈｅ ｂｒｅａｄｔｈｓ, ｎｉｃｈｅ ｓｉｍｉｌａｒｉｔｉｅｓ ａｎｄ ｎｉｃｈｅ ｏｖｅｒｌａｐｓ ｏｆ １３ ｓｐｅｃｉｅｓ (ｉｍｐｏｒｔａｎｃｅ ｖａｌｕｅ ｌａｒｇｅｒ ｔｈａｎ １ ) ｗｅｒｅ ａｎａｌｙｚｅｄ ｑｕａｎｔｉｔａｔｉｖｅｌｙ ｂａｓｅｄ ｏｎ ｔｈｅ ｄａｔａ ｃｏｌｌｅｃｔｅｄ ｉｎ ２０１３. Ｔｈｅ ｒｅｓｕｌｔｓ ｄｅｍｏｎ-ｓｔｒａｔｅｄ ｔｈａｔ ｔｈｅ ｎｉｃｈｅ ｂｒｅａｄｔｈｓ ｏｆ Ｃｙｃｌｏｂａｌａｎｏｐｓｉｓ ｍｕｌｔｉｎｅｒｖｉｓ, Ｒｈｏｄｏｄｅｎｄｒｏｎ ｌａｔｏｕｃｈｅａｅ ａｎｄ Ｅｕｒｙａ ｒｕｂｉｇｉｎｏｓａ ｖａｒ. ａｔｔｅｎｕａｔｅ ｗｅｒｅ ｒｅｌａｔｉｖｅｌｙ ｌａｒｇｅｒ, ｗｉｔｈ Ｈｕｒｌｂｅｒｔ ｎｉｃｈｅ ｂｒｅａｄｔｈ ｖａｌｕｅｓ (Ｂａ) ｂｅｉｎｇ ０.８７８, ０.８２５, ０.８０６, ｒｅｓｐｅｃｔｉｖｅｌｙ, ｗｈｉｌｅ ｔｈｅ ｎｉｃｈｅ ｂｒｅａｄｔｈｓ ｏｆ Ｃｌｅｙｅｒａ ｐａｃｈｙｐｈｙｌｌａ, Ｆａｇｕｓ ｌｕｃｉｄａ ａｎｄ Ｓｙｃｏｐｓｉｓ ｓｉｎｅｎｓｉｓ ｗｅｒｅ ｒｅｌａｔｉｖｅｌｙ ｓｍａｌｌｅｒ, ｗｉｔｈ Ｂａ ｖａｌｕｅｓ ｂｅｉｎｇ ０.３４１, ０.３２０, ０.２７２, ｒｅｓｐｅｃｔｉｖｅｌｙ. Ｔｈｅ ｓｐｅｃｉｅｓ ｎｉｃｈｅ ｂｒｅａｄｔｈ ｗａｓ ｎｏｔ ｒｅｌａｔｅｄ ｔｏ ｉｔｓ ｉｍｐｏｒｔａｎｃｅ ｖａｌｕｅ, ｂｕｔ ｗａｓ ｓｉｇｎｉｆｉｃａｎｔｌｙ ｐｏｓｉｔｉｖｅｌｙ ｃｏｒｒｅｌａｔｅｄ ｗｉｔｈ ｔｈｅ ｅｖｅｎｎｅｓｓ ｏｆ ｉｍｐｏｒｔａｎｃｅ ｖａｌｕｅｓ ａｃｒｏｓｓ ｄｉｆｆｅｒｅｎｔ ｐｌｏｔｓ. Ｔｈｅ ｎｉｃｈｅ ｓｉｍｉｌａｒｉｔｙ ｂｅｔｗｅｅｎ Ｃｙｃｌｏｂａｌａｎｏｐｓｉｓ ｍｕｌｔｉｎｅｒｖｉｓ ａｎｄ Ｃａｍｅｌｌｉａ ｃｕｓｐｉｄａｔｅ ｗａｓ ｔｈｅ ｌａｒｇｅｓｔ, ｂｅｉｎｇ ０.８３２, ｗｈｉｌｅ ｔｈａｔ ｂｅｔｗｅｅｎ Ｉｌｅｘ ｅｄｉｔｉｃｏｓｔａｔａ ａｎｄ Ｓｙｃｏｐｓｉｓ ｓｉｎｅｎｓｉｓ ｗａｓ ｔｈｅ ｓｍａｌｌｅｓｔ, ｂｅｉｎｇ ０.２４８. Ｄｅｓｐｉｔｅ ｏｆ ｓｍａｌｌ ｎｉｃｈｅ ｂｒｅａｄｔｈｓ, ｉｎ ａｄｄｉｔｉｏｎ, ｔｈｅ ｎｉｃｈｅ ｓｉｍｉｌａｒｉｔｙ ｂｅｔｗｅｅｎ Ｃｌｅｙｅｒａ ｐａｃｈｙｐｈｙｌｌａ ａｎｄ Ｆａｇｕｓ ｌｕｃｉｄａ ｗａｓ ｈｉｇｈ (０.７５８) ｄｕｅ ｔｏ ｔｈｅｉｒ ｓｉｍｉｌａｒ ｈａｂｉｔａｔ ｒｅｑｕｉｒｅｍｅｎｔｓ. Ｌｏｗ ｎｉｃｈｅ ｓｉｍｉｌａｒｉｔｉｅｓ ｗｅｒｅ ｆｏｕｎｄ ｉｎ ｔｗｏ ｐａｉｒ ｏｆ ｓｐｅｃｉｅｓ ｉｎ ｔｈｅ ｓａｍｅ ｇｅｎｕｓ: ｂｅｔｗｅｅｎ Ｃｌｅｙｅｒａ ｍｕｌｔｉｎｅｒｖｉｓ ａｎｄ Ｃ. ｓｔｅｗａｒｄｉａｎａ, ａｎｄ ｂｅｔｗｅｅｎ Ｉｌｅｘ ｆｏｒｍｏｓａｎａ ａｎｄ Ｉ. ｅｄｉｔｉｃｏｓｔａｔａ. Ｓｐｅｃｉｅｓ ｗｉｔｈ ｗｉｄｅ ｎｉｃｈｅ ｂｒｅａｄｔｈ ｏｆｔｅｎ ｈａｄ ｈｉｇｈ ｄｅｇｒｅｅｓ ｏｆ ｎｉｃｈｅ ｏｖｅｒｌａｐ ｗｉｔｈ ｏｔｈｅｒ ｓｐｅｃｉｅｓ, ａｎｄ ｌａｒｇｅ ｎｉｃｈｅ ｓｉｍｉｌａｒｉｔｙ ｗａｓ ｏｆｔｅｎ ａｓｓｏｃｉａｔｅｄ ｗｉｔｈ ｈｉｇｈ ｄｅｇｒｅｅｓ ｏｆ ｎｉｃｈｅ ｏｖｅｒｌａｐ. Ｌｏｗ ｄｅｇｒｅｅｓ ｏｆ ｎｉｃｈｅ ｏｖｅｒｌａｐ ｗｅｒｅ ｆｏｕｎｄ ｂｅｔｗｅｅｎ Ｃｌｅｙｅｒａ ｍｕｌｔｉｎｅｒｖｉｓ ａｎｄ Ｃ. ｓｔｅｗａｒｄｉａｎａ, ａｎｄ ｂｅｔｗｅｅｎ Ｉｌｅｘ ｆｏｒｍｏｓａｎａ ａｎｄ Ｉ. ｅｄｉｔｉｃｏｓｔａｔａ. Ｉｎ ａ ｗｏｒｄ, ｌｏｗ ｄｅｇｒｅｅｓ ｏｆ ｎｉｃｈｅ ｏｖｅｒｌａｐ ｆｏｕｎｄ ｉｎ ｔｈｉｓ ｓｔｕｄｙ ｓｕｇｇｅｓｔｅｄ ｗｅａｋ ｉｎｔｅｒｓｐｅｃｉｅｓ ｃｏｍｐｅｔｉｔｉｏｎ ａｍｏｎｇ ｄｏｍｉｎａｎｔ ｓｐｅｃｉｅｓ ａｎｄ ｔｈｅｒｅｆｏｒｅ ａ ｐｏｔｅｎｔｉａｌｌｙ ｓｔａｂｌｅ ｐｌａｎｔ ｃｏｍｍｕｎｉｔｙ ｉｎ ｔｈｉｓ ｆｏｒｅｓｔ. Ｔｈｉｓ ｐａｐｅｒ ｒｅｖｅａｌｅｄ ｔｈｅ ｎｉｃｈｅ ｃｈａｒａｃｔｅｒｉｓｔｉｃｓ ｏｆ ｄｏｍｉｎａｎｔ ｓｐｅｃｉｅｓ ｐｏｐｕｌａｔｉｏｎｓ ａｎｄ ｓｔｒｕｃｔｕｒａｌ ｓｔａｂｉｌｉｔｙ ｏｆ ｔｈｅ ｃｏｍｍｕｎｉｔｙ, ａｎｄ ｉｔ ｗｏｕｌｄ ｐｒｏｖｉｄｅ ｔｈｅｏｒｅｔｉｃａｌ ｂａｓｉｓ ｆｏｒ ｔｈｅ ｒｅｓｅａｒｃｈ ｏｆ ｂｉｏｄｉｖｅｒｓｉｔｙ ｃｏｎｓｅｒｖａｔｉｏｎ, ｓｕｃｃｅｓｓｉｏｎ, ｐｏｐｕｌａｔｉｏｎ ｅｖｏｌｕｔｉｏｎ. Ａｎｄ ｉｔ ａｌｓｏ ｃｏｕｌｄ ｐｒｏｖｉｄｅ ｒｅｆｅｒｅｎｃｅ ｆｏｒ ｔｈｅ ｎａｔｕｒｅ ｒｅｓｅｒｖｅ ｍａｎａｇｅｍｅｎｔ ｉｎｓｔｉｔｕｔｉｏｎ ｔｏ ａｄｊｕｓｔ ａｎｄ ｉｍｐｒｏｖｅ ｃｏｎｓｅｒｖａｔｉｏｎ ｍｅａｓｕｒｅｓ. [ABSTRACT FROM AUTHOR]

The Wawushan Mountain National Forest Park in Sichuan Province, where there is relatively intact Castanopsis platyacantha-Schima sinensis formations, is a typical representative of the mid-subtropical moist evergreen broad-leaved forest in West China. Using the soil core method, this study investigated the fine root distribution and characteristics of carbon and nitrogen of sample C. platyacantha which is the main constructive species in this formation. The results were as follows: (1) The total fine root biomass of C. platyacantha was 173.62 g·m−2 and the total biomass of live fine roots was 135.29 g·m−2. (2) The fine root biomass, root length density, root surface area and specific root length decreased with the increase of soil depth, and their proportions in 0－30 cm layers were 67.23%, 69.53%, 69.48% and 57.20%, respectively; root length density, root surface area and specific root length decreased significantly with increasing root diameter, and 58.84%, 52.59% and 51.36% of them were in the roots that diameter was less than 1 mm, respectively. (3) Root extinction coefficient in biomass, length and surface area of C. platyacantha fine root increased with the rise of the root diameter. (4) In the first soil layer, the roots C content increased significantly with the rising root diameter, but there was no significant difference in other soil layers; the C content of the roots whose diameter was less than 2 mm in the first soil layer was significantly lower than other soil layers, while the differences of roots C content of greater than 2 mm among soil layers was insignificant. (5) The roots N content decreased with the increase of soil depth and root diameter while the C/N ratio value was opposite. These results reflected the vertical distribution of the secondary forest underground fine root system and nutrient characteristics, which would provided some basic data for revealing the subsurface ecological processes and the effects of environmental change on ecological processes in the underground in the ecosystem. [ABSTRACT FROM AUTHOR]

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Fire plays a major role in fire-dependent ecosystems in shaping plant traits, community assemblage, and in maintaining biodiversity and sustaining ecosystems. Excluding fire from fire-dependent ecosystems can substantially alter these ecosystems. This study mainly investigates the how the zonal vegetation evergreen broad-leaved forests as well as widely distributed vegetation Pinus yunnanensis forest and shrubland in the Central Yunnan Plateau adapt to fire, and addresses the role of fire in the Central Yunnan Plateau ecosystem to determine whether this ecosystem is fire-dependent. Re-sprouting trees and shrubs composed about 90.6% of the dominant taxa. In re-sprouting species, 41 species (77.4% of all re-sprouting species) were observed re-sprout from underground basal burls after a fire. After a fire, 100% of all trees and tall shrubs, 93.6% of all shrubs and 73.9% of all herbs recovered. Two serotinous tree taxa were found, including two varieties of P . yunnanensis (var. pygmaea and var. yunnanensis ) which is a dominant and the most common tree species in this region. All these were identified here as weakly serotinous species. The degree of serotiny was 50.4% for P . yunnanensis var. yunnanensis and 74.7% for var. pygmaea . Heat shock resulted in higher seed germination rates for both varieties of P . yunnanensis . Dominant and common taxa in these two typical forest types had typical traits of species known to be adapted to fire; forest fire did not significantly reduce number of species. Based on the above results, the Central Yunnan Plateau ecosystem is a fire-dependent system. Wildfire plays an important role in the community assembly for the semi-humid evergreen broad-leaved forests, P. yunnanensis forest and shrub communities. Wildfire should not be viewed as a totally catastrophic event in forests of the Central Yunnan Plateau. In theory this region appropriates to carry out prescribed burning. [ABSTRACT FROM AUTHOR]

The spatial distribution of species in forest ecosystems involves the underlying ecological processes or mechanisms of population and community structure, as well as forest dynamics. Because the relative importance of these factors can shift across life history stages, assessment of local population and community structures in the context of life history stages is essential for understanding forest dynamics. In this study, we investigated the changes in the spatial patterns of seed dispersal as well as seedling and sapling recruitment for Castanopsis fargesii, a dominant tree species in a subtropical evergreen broad-leaved forest in China. We found notably aggregated spatial patterns for C. fargesii seeds during the seed dispersal. A majority of seeds and newly germinated seedlings aggregated under adult tree canopies, suggesting a decreased efficiency in secondary dispersal for C. fargesii within this evergreen broad-leaved forest. During the later stages of life history (i.e., seedling and sapling stages), the spatial distribution of C. fargesii getting segregated. This is caused by a negative density dependence mechanism in seedling recruitment, rather than by spatial dispersion due to secondary dispersal. By incorporating the patterns and processes across the life history stages of dominant species of evergreen broad-leaved forests, we can add specific details in developing methods of stage-based in situ forest management and conservation frameworks. [ABSTRACT FROM AUTHOR]

Subtropical forests in China constitute the major expanse of evergreen broad-leaved forest in East Asia. The significant genetic divergence of the keystone tree species should be expected due to the huge geomorphological and environmental changes from west to east in subtropical China. In this study, a total of 652 individuals from 27 populations of Castanopsis fargesii throughout its natural range in mainland China were genotyped with eight chloroplast microsatellite markers to investigate genetic diversity, population differentiation, and demographic history of C. fargesii. Phylogeographic structure among populations of C. fargesii was evidenced by the permutation test, revealing that N was significantly higher than G . The strong genetic differentiation found among populations was well in accordance with isolation-by-distance model. In addition, significant isolation by elevation was detected among populations. Significant genetic differentiations were revealed among the west, center, and east regions by approximate Bayesian computations (ABC). The genetic divergence might reflect the regional responses to the fast and dramatic uplift of Yunnan-Guizhou Plateau and Wuyi mountain range in the Pleistocene. In the present study, contraction-expansion process was detected in the west, center, and east regions, indicating that geomorphological remodeling together with climatic changes in the Pleistocene had strong impact on genetic structure of C. fargesii. [ABSTRACT FROM AUTHOR]

Based on the field investigation and the data combination from literature, vegetation carbon storage, carbon density, and their spatial distribution were examined across six forest community types (Schima superba-Castanopsis fargesii community, S. superba-C. fargesii with C. sclerophylla community, S. superba-C. fargesii with Distylium myricoides community, Illicium lanceolatum -Choerospondias axillaris community, Liquidambar formosana -Pinus massoniana community and Hedyotis auricularia -Phylostachys pubescens community) in Tiantong National Forest Park, Zhejiang Province, by using the allometric biomass models for trees and shrubs. Results showed that: Among the six communities investigated, carbon storage and carbon density were highest in the S. superba -C. fargesii with C. sclerophylla community (storage: 12113. 92 Mg C; density: 165. 03 Mg C · hm-2), but lowest in the I. lanceolatum-C. axillaris community (storage: 680. 95 Mg C; density: 101. 26 Mg C · hm-2). Carbon storage was significantly higher in evergreen trees than in deciduous trees across six communities. Carbon density ranged from 76. 08 to 144. 95 Mg C.hm-2, and from 0. 16 to 20. 62 Mg C · hm-2 for evergreen trees and deciduous trees, respectively. Carbon storage was highest in stems among tree tissues in the tree layer throughout communities. Among vegetation types, evergreen broadleaved forest had the highest carbon storage (23092. 39 Mg C), accounting for 81. 7% of the total carbon storage in all forest types, with a carbon density of 126. 17 Mg C · hm-2. Total carbon storage for all vegetation types in Tiantong National Forest Park was 28254. 22 Mg C, and the carbon density was 96. 73 Mg C · hm-2. [ABSTRACT FROM AUTHOR]

The redistribution processes of rainfall due to the canopy were studied on three typical forest types (Chinese fir forest, evergreen broad-leaved forest and Phyllostachys pubescens forest) in Dagangshan Mountains of Jiangxi Province. The results showed that from April to June, 2012, the total precipitation was 531. 6 mm, with the maximum single rainfall of 61. 7 mm. The rainfall in this area was mainly light and moderate. During the research period, the total throughfall of P. pubescens forest was the greatest, and that of evergreen broad-leaved forest was the smallest. The throughfall of P. pubescens and Chinese fir forest were almost equal at the same rainfall intensity. However, the throughfall of evergreen broad-leaved forest was smaller than those of the other two types of forest at the same high rainfall intensity. Throughfall presented a distinct spatial variability within each forest. Stemflow of Chinese fir forest, evergreen broad-leaved forest and P. pubescens forest were 1. 4%, 8. 9% and 8. 8%, respectively. There were significant differences (P<0. 01) in stemflow between the Chinese fir forest and the other two types of forests. In addition, the moisture degree of forests before a rain event greatly influenced the quantity of the stemflow. The effect was strongest in the Chinese fir plantation and weakest in the P. pubescens forest. The proportion of interception to rainfall was in a descending order of 30. 5%, 25. 5% and 19. 2% for the Chinese fir forest, the evergreen broad-leaved forest and the P. pubescens forest, respectively. The Chinese fir forest had the obviously greater interception rate than the other two types of forests under usual rain- fall in the study area. [ABSTRACT FROM AUTHOR]

Evergreen broad-leaved forest is an important forest type in China. This paper analyzes the allocation characteristics of vegetation and soil carbon pool of evergreen broad-leaved forest, to understand the current status of research on the carbon storage of evergreen broad-leaved forest as well as shortcomings. In the context of global climate change, it is necessary to carry out the long-term research of evergreen broad-leaved forest, in order to grasp the formation mechanism of evergreen broad-leaved forest productivity, and the mpact of climate change on the carbon sequestration function of evergreen broad-leaved forest ecosystem. [ABSTRACT FROM AUTHOR]

Paddy fields surrounded by forests are characteristic of the rural landscapes in East Asia. These characteristic landscapes are maintained by agricultural activities; recently, however, local and regional changes in economic and social systems have resulted in their deterioration. In order to conserve these landscapes, the diversity of land-use systems should be documented, and the human impact on landscape structure should be analyzed. In this study, landscape structure, stand structure, and influence of human activity on the landscape were examined for a hilly agricultural area in Fenghua City, Zhejiang Province, China. Eleven types of landscape elements were recognized that include evergreen broad-leaved forests, evergreen coniferous ( Pinus massoniana) forests, tall bamboo ( Phyllostachys pubescens) forests, small bamboo ( Phyllostachys praecox f. prevernalis) plantations, tea gardens, grasslands, dry arable fields, paddy fields, residential areas, bare ground, and open water. In the study plots, which were established in the main forest types, the species name, cover abundance, and sociability of vascular plants were recorded, and tree height and diameter at breast height were measured. In addition, the amount of fuelwood collected from the forests was determined. There were many component species common to both secondary and natural forests, but the stand structure for these forests was considerably different. Cyclobalanopsis ( Quercus) glauca, which had adapted to being frequently cut, was found to be the preferred species for fuelwood. [ABSTRACT FROM AUTHOR]

The recalcitrant understory fern layer is an important ecological filter for seedling regeneration, yet how the fern layer influences seedling regeneration dynamics remains unclear. Here we transplanted 576 seedlings of four dominant tree species, Castanopsis fargesii , Lithocarpus glaber , Schima superba and Hovenia acerba , to the treatments of Diplopterygium glaucum retention and removal under an evergreen broad-leaved forest in eastern China. We monitored the survival, growth and biomass data of these seedlings for 28 months, and then used generalized linear mixed models to evaluate the treatment effects on seedling survival, growth, biomass and root-shoot ratio. Our results showed that fern retention significantly inhibited the seedling establishment of all four species. During the seedling development stage, the seedling relative growth rate of L. glaber decreased under fern retention, which was not the case for the other three species. Root-shoot ratio of C. fargesii and L. glaber increased significantly under fern retention. Our findings provide new evidence of the filtering effect of a recalcitrant fern understory. Notably, we observed that the response of tree seedlings to the recalcitrant fern understory was more sensitive in the establishment stage. Finally, our work highlights that the filtering effect of the recalcitrant fern understory changes depending on the regeneration stages, and that shade-tolerant species, C. fargesii and L. glaber were even more affected by fern disturbed habitats, suggesting that effective management should attempt to curb forest fern outbreaks, thus unblocking forest recruitment., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Liu, Liang, Yang, Zhang, Shen, Zhang and Wang.)