2022 Vol. 35, No. 3
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2022, 35(3): 1-8.
doi: 10.13275/j.cnki.lykxyj.2022.03.001
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Abstract:
Objective To explore how legumes influence other species in the tropical mountain rainforest, and mechanism related to these influences. Method Their neighboring abundance, richness, and survival rates of these seven leguminous trees were calculated and compared with the neighboring non-leguminous trees. Result There was no significant differences on the neighboring abundance, richness, and survival rates from 2012 to 2018. Relative neighboring abundance and richness of Ormosia semicastrata, Archidendron clypearia and A. lucidum were higher than those of non-leguminous trees both in 2012 and 2018. Relative neighboring abundance and richness of other four leguminous were lower than those of non-leguminous trees. In terms of neighboring survival rates, O. semicastrata, O. fordiana, and A. clypearia were higher than those of non-leguminous trees, which suggests that O. semicastrata is inclined to have facilitation effects on the neighboring species, while O. xylocarpa and A. utile have negative effects on the neighboring species. Neighboring abundance, richness, and survival rates of seven leguminous trees showed no significant linear correlations with leaf nitrogen contents and nitrogen fixation activities, although it showed significant correlations between the neighboring survival rates and leaf nitrogen contents at the 4 m radius distance from the focal legume trees. Conclusion In general, different legumes have various effects on the neighboring species. O. semicastrata is more likely to have facilitative effects on the neighboring trees. A. utile and O. xylocarpa exhibit negative effects on the neighboring trees. The effects of other four leguminous trees on the neighboring trees vary on three neighboring abundance, richness, and survival rate indices.
2022, 35(3): 9-17.
doi: 10.13275/j.cnki.lykxyj.2022.03.002
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Objective To provide technical support for the establishment of somatic embryogenesis multiplication and genetic transformation of Pinus taeda, the somatic embryogenesis technology system of P. taeda were established and optimized. Methods The immature zygotic embryos with superior genotypes of P. taeda were used. The induction conditions of embryogenic callus were optimized based on the genotype, cone collection period, basic medium, plant hormone combination, and concentration, etc. The embryogenic callus with good proliferation and embryo suspensor mass were selected to carry out the orthogonal test of somatic embryo maturation. In addition, the cotyledon embryos with normal development were selected for germinating. And after 8 weeks, transplanting was carried out. Results There were significant effects of genotype, development stage of zygote embryo, basic medium, plant growth regulator combinations, and concentrations on embryogenic callus induction. Among the six genotypes of P. taeda, the induction rate of Rongshan 52 genotype was the highest, 63.33%. The best sampling time for explants was the zygotic embryo in the split polyembryonic stage (around July 20). The embryogenic callus induction rate on DCR medium was the highest, 34.00%. The induction rate in the PGR combinations and concentrations with 2,4-D 1.0 mg·L−1, 6-BA 0.5 mg·L−1, NAA 2.0 mg·L−1 and ABA 5.0 mg·L−1 was the highest, 50.00%. Embryogenic calli were cultured on MLP for 14 days, and then transferred to somatic embryo induction medium containing ABA 8.0 mg·L−1, maltose 40.0 g·L−1 and PEG 8000 140 g·L−1. The average number of somatic embryos was 411·g−1, the somatic embryo germination rate was 93.33%, and the survival rate of somatic embryo seedling transplantation was more than 80%. Conclusion Somatic embryogenesis of P. taeda was optimized, and the induction rate of somatic embryos was significantly improved. This study provides a preliminary technique for the establishment of large-scale embryogenic transformation of P. taeda.
2022, 35(3): 18-26.
doi: 10.13275/j.cnki.lykxyj.2022.03.003
Abstract:
Objective To provide a scientific basis for the evaluation of soil carbon pool stability and tree species selection in coastal reclamation areas, the vertical variations and potential influence mechanism of soil organic carbon and labile carbon fractions in different stands were investigated. Method We studied the vertical distribution characteristics of soil organic carbon, microbial biomass carbon, and dissolved organic carbon and their relationships with soil physicochemical properties and enzyme activities in 0-100 cm depth in Populus deltoides, Metasequoia glyptostroboides and Ginkgo biloba plantations. Result The contents of soil organic carbon, microbial biomass carbon and dissolved organic carbon gradually decreased with the increase of soil depth in three stands. The contents of soil organic carbon in the 0-20 cm soil layer were significantly higher in M. glyptostroboides and P. deltoides stands than that in the G. biloba stands, but there was no significant difference in the 20-100 cm soil layer among the three stands. The contents of microbial biomass carbon and dissolved organic carbon in the soil layer of 0-60 cm were the highest in the M. glyptostroboides stand, followed by P. deltoides and G. biloba stands, and there were no significant differences in the 60-100 cm soil layer among the three stands. The ratios of soil dissolved organic carbon/soil organic carbon and microbial biomass carbon/soil organic carbon initially increased and then decreased with the increase of soil depth (except for the ratio of soil dissolved organic carbon/soil organic carbon). The ratios of soil dissolved organic carbon/soil organic carbon and microbial biomass carbon/soil organic carbon were higher in 20-60 cm soil layer. Overall, the ratios of soil dissolved organic carbon/soil organic carbon and microbial biomass carbon /soil organic carbon in the three stands had slight difference in all soil layers. Redundancy analysis and correlation analysis showed that soil organic carbon and labile organic carbon fractions of each stand were significantly positively correlated with soil total nitrogen, hydrolyzable nitrogen and invertase activity, and negatively correlated with soil pH. Conclusion Tree species greatly affected the labile organic carbon in the soil profile in coastal reclamation areas, and which has a weak effect on the stability of soil organic carbon.
2022, 35(3): 27-37.
doi: 10.13275/j.cnki.lykxyj.2022.03.004
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Objective To study the plasticity mechanism of tree crown morphology adapting to the external environment. Method Taking Larix olgensis in Xiaoxing'anling Mountain as the research object, using detailed crown radius survey data, the phenomenon of crown displacement of L. olgensis was studied, and the relationship between crown displacement and tree size and competition was analyzed. Result At the level of individual tree, the average value of the crown radius variation coefficient of trees in sample plots with different ages was larger than 20%, and the crown radius variation coefficient of less than 1/5 trees was less than 15%. The average value of crown displacement distance of L. olgensis was between 0.35～0.51 m in the plots with different ages. The maximum value of crown displacement distance of trees in all plots was more than 1.2 m, and the maximum value of crown displacement distance of trees in mature forest was 1.73 m. No specific direction deviation was observed in the direction of crown deviation, which was evenly distributed. In the young forest, the crown displacement distance was significantly and positively correlated with DBH, crown length and average crown radius, and the crown displacement distance increased with the increase of trees. In the middle-aged forest and near mature forest, the crown displacement index was negatively correlated with DBH, tree height and average crown radius, and positively correlated with height diameter ratio. In mature forest, the correlation between crown displacement and tree size was not significant. In young forest, middle-aged forest and near mature forest, there was a significant positive-correlation between crown displacement and competitive pressure, but there was no significant correlation between crown displacement and competition index in mature forest. The average competition index calculated based on crown center coordinate was less than that calculated based on stem coordinate. Conclusion The crown deviation distance of L. olgensis generally increases with the increase of forest age, and is affected by different degrees of competition at different development stages. The crown displacement will reduce the average competition index and the competition pressure of the stand to a certain extent.
2022, 35(3): 38-46.
doi: 10.13275/j.cnki.lykxyj.2022.03.005
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Object This study aims to investigate the phosphate-solubilizing characteristics of Enterobacter aerogenes and its growth-promoting effect on Phyllostachys edulis. Methods The effects of different carbon sources, nitrogen sources, and environmental factors on phosphate solubilizing ability of E. aerogenes were evaluated by culture method of shaking liquid. The effects of the strain on available nutrients, enzyme activities, total phosphorus contents of roots and leaves, and phosphorus fractions of leaves in rhizosphere soil of P. edulis were studied using pot experiment in greenhouse. Results E. aerogenes displayed the strongest phosphate-dissolving capacity on tricalcium phosphate when the initial pH was 5.5～6.5, the volume of liquid was 1/5 or 2/5, and salt ion concentration was 0 or 1.0 g·L−1. Carbon source was sucrose or glucose, and nitrogen source was ammonium sulfate. The average phosphate solubilization of E. aerogenes to Ca2(PO4)3 and CaHPO4 was 331.83 mg·L−1 and 345.91 mg·L−1, respectively. Compared with the control treatment, the rhizosphere soil available phosphorus, phosphatase, urease activities and leaf net photosynthetic rate increased by 50.9%, 20.6%, 21.0% and 42.0% in P. edulis seedlings inoculated with E. aerogenes. The ground diameter, seedling height, and biomass accumulation were higher by 31.0%, 23.5% and 44.5%, respectively. Total phosphorus contents of roots and nucleic acid phosphorus contents of leaves in P. edulis significantly increased while residual phosphorus contents in leaves significantly decreased. Total phosphorus, metabolic phosphorus, and sugar phosphorus contents in leaves were steady due to inoculating E. aerogenes. Conclusion E. aerogenes has potential to highly adapt to the environment and improves the growth of P. edulis seedlings via increasing root phosphorus absorption and leaf nucleic acid phosphorus accumulation. It is also a potential strain for the development of special biological fertilizer for bamboo forest in phosphorus deficient area of Southern hills and has a good application prospect.
2022, 35(3): 47-54.
doi: 10.13275/j.cnki.lykxyj.2022.03.006
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Objective To investigate the process between growth and defense of Aquilaria sinensis, and reveal physiological mechanism of agarwood formation in response to fungi and mechanical damage stress. Method Two methods including injection of fungal agent and drilling with mechanical damage were used to induce agarwood formation with the three-year-old Aquilaria sinensis trees. Subsequently, hormone content, antioxidant enzyme activity, total phenols and terpenoids content, and photosynthesis and chlorophyll fluorescence characteristics were periodically analyzed during agarwood formation. Result At the initial stress stage, the contents of defense related hormones, jasmonic acid, salicylic acid and ethylene increased significantly, while the contents of growth related hormones, gibberellin, and auxin decreased. At the later stress stage, the contents of jasmonic acid, salicylic acid, and ethylene gradually decreased, while the contents of gibberellin and auxin gradually increased. The activities of antioxidant enzymes and the contents of phenols and terpenes were significantly higher in the stress groups than those of the control group. The contents of phenols and terpenoids increased with the increase of treatment duration, and the rate of increase decreased. Three months after treatments, the photosynthesis and chlorophyll fluorescence were inhibited, while inhibition was alleviated after six months . Conclusion In response to the stress of fungus and mechanical damage, defense related hormones increase significantly, as well as the activities of antioxidant enzymes. In addition, the secondary metabolic defense products such as phenols and terpenes increase and photosynthesis is inhibited. The strength of defense response decrease with the increase of treatment duration and trees recover the growth. Thus, agarwood formation is the process to that Aquilaria sinensis trees produce secondary metabolites by strengthening the defense response, which is a trade-off between growth and defense.
2022, 35(3): 55-62.
doi: 10.13275/j.cnki.lykxyj.2022.03.007
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Objective To clarify the effect of microbial agents and their application on the restoration of wind and water erosion areas in the reclamation of poplar, and provide a theoretical basis for the soil restoration in wind and water erosion areas. Method Arbuscular mycorrhizal fungi (AMF), Trichoderma harzianum(TH), and Bacillus mucilaginous were used(BM) as microbial inoculum for remediation. Populus simonii was used as reclaimed vegetation. One or mixed microbial Agents were fertilized for soil reclamation were set up in this study. The improvement effect of microbial agents on soil in this type area were determined by measuring soil physicochemical properties and enzyme activities. Result The result showed that the Soil water content (WC) and Soil organic matter content (SOC) were the highest using single biofertilizer of BM and AMF treatment, respectively. The pH and conductivity (EC) under the AMF + BM mixed treatments were the highest. Soil enzyme activities were closely related to the types of microbial agents and application methods. The enzyme activities of each biofertilizer treatment had been improved, and the Soil enzyme index (SEI) of AMF + BM treatment was 0.84, which was the highest. The microbial agents promoted the recovery of soil nutrients and improved enzyme activities. Among all treatments, AMF + BM treatment had the best effect, with enzyme recovery index (ERI) of 238.89% and Nutrient recovery index (NRI) of 178.15%. Redundancy Analysis (RDA) analysis showed AMF + BM treatment improved soil pH, TP, Catalase (CAT), Urease (URE), and Soil respiration indexes. Conclusion Combined application of AMF and PGPR improves soil physicochemical properties and soil enzyme activities in the water-wind erosion crisscross region. Among them, the mixed microbial-agents of AMF + BM has the best effect.
2022, 35(3): 63-71.
doi: 10.13275/j.cnki.lykxyj.2022.03.008
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Objective To understand the characteristics of nitrogen (N) transformation and N supply capacity of forest soils, and provide scientific basis for the rational management of forest ecosystem. Method In this study, two surface soils of Pinus koraienis coniferous plantations and natural secondary broad-leaved mixed forests were selected in cold temperate zone in Northeast China. The characteristics of gross N transformation rates in different soil depths were investigated through a laboratory incubation experiment using the 15N paired tracing technique and numeric FLUAZ model. Result Gross N transformation rates in forest soils were affected by forest type, soil depth, and their interactions. Gross N mineralization and immobilization rates in the soil of Pinus koraienis were significantly lower than those in natural secondary broad-leaved mixed forest, while gross nitrification rate was significantly higher than that in natural secondary broad-leaved mixed forest. Soil gross N transformation rates under the two forest types decreased significantly with increasing soil depth. Soil gross N mineralization and immobilization rates were significantly positively correlated with soil pH, contents of soil organic carbon (SOC), water soluble organic carbon (SOCw), and water-soluble organic nitrogen (SONw), whereas soil gross nitrification rates were significantly negatively correlated with soil pH. The ratio of gross nitrification rate to NH4+ immobilization rate in the soil of Pinus koraienis plantations was significantly higher than that in natural secondary broad-leaved mixed forests, but the immobilization rate of NO3− was significantly lower than that in natural secondary broad-leaved mixed forests. Conclusion The characteristics of soil N transformation between the two forest types are significantly different. Compared with natural secondary broad-leaved mixed forests, Pinus koraienis plantation soil has stronger NO3− production capacity and weaker inorganic N retention capacity, resulting in higher risk of NO3− leaching, whereas the weak nitrification and the processes of N mineralization and immobilization are coupled tightly in natural secondary broad-leaved mixed forests, leading to low risk of NO3− accumulation and leaching.
2022, 35(3): 72-81.
doi: 10.13275/j.cnki.lykxyj.2022.03.009
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Objective To reveal the role of soil fauna on litter decomposition in karst forests and understand deeply the nutrients recycling in the plant-soil system in the ecologically fragile karst region. Method A one-year field litterbag experiment with local dominant herbaceous and woody species litter, i.e., Imperata cylindrica (IC), Platycarya longipes (PL), and Cladrastis platycarpa (CP), was carried out to study the influence of soil fauna with different body sizes on litter decomposition through ordination analysis and random forest model. Result Results showed that litter mass loss rate differed significantly among litter treatments. The highest and lowest mass loss rate was recorded by herbaceous litter (IC) and woody litter (CP), respectively. Litter mass loss rate was negatively correlated with litter C/N values. On average, soil fauna contributed 24.89% to forest litter decomposition, of which the contribution rate of meso-, and micro-fauna to litter decomposition was 15.34%, higher than that of macrofauna (9.55%), Soil fauna mainly contributed to litter mass loss in the early stage of decomposition. A total of 13 733 individuals of soil fauna which belonged to 21 groups were captured in litterbags. Acarina and Collembola were the dominant groups. Prostigmata, Entomobryomorpha, Neelipleona, Pseudoscorpiones, Mesostigmata, and Pselaphidae played a vital role in litter decomposition through random forest model. Conclusion In the central Guizhou karst forest, litter mass loss rate is negatively correlated with litter C/N values, except herbaceous litter. Soil fauna has a positive effect on litter decomposition, especially in the early stage of decomposition.
2022, 35(3): 82-92.
doi: 10.13275/j.cnki.lykxyj.2022.03.010
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Objective This study aims to investigate the effects of urban-rural gradient and forest stand type on the fractions of forest soil aggregates and their stability mechanisms and provide a theoretical basis for the elucidation of regional soil quality assessment. Methods Three typical forest stand types under the urban-rural gradient of the Pearl River Delta urban agglomerates were selected to analyze the characteristics of the stability of soil aggregates in the 0-30 cm soil layer, as well as their influencing factors. Results The soil aggregates of the three forest types mainly consisted of large aggregates (> 0.25 mm). The water-stable aggregates of Conclusion The soil agglomeration structure stability is closely related to urban-rural gradient, stand type, and soil layer. The transformation of pinus massoniana forest into mixed coniferous and broad-leaved forest can effectively improve the forest soil quality and erosion resistance.
2022, 35(3): 93-102.
doi: 10.13275/j.cnki.lykxyj.2022.03.011
Abstract:
Objective To quantitatively characterize the relationship between forest volume as well as biomass and stand age for predicting forest volume and biomass in the future. Methods Based on the forest inventory data with five times of Pinus massoniana, Pinus elliottii and Cunninghamia lanceolata in Guangdong, the stand volume and biomass growth models were established by constructing the relationship between the average DBH and stand age, which was developed with 8 forms, respectively, including growth potential and grow rate classifications, developing models with competition or not, and developing models separately or simultaneously. Result (1) The determination coefficients of the eight model systems were more than 0.980. The mean prediction errors (MPE) were within ±1%. The total relative errors were within ±0.5%. Comprehensively considering the goodness of fit and prediction accuracy of each model, the separate model based on the classification of parameter related to growth rate without considering competition was the best. Moreover, model with competition did not significantly improve the model performance. (2) The gap of MPE values of the best stand volume model and worst model was 10.36%, and the gap of biomass model was 10.22%, which indicated that the models were suitable. Besides, the MPE values from the second and third period data were larger than the first and the last period data. (3) The growth potential of Pinus massoniana was the largest, by contrast that of Cunninghamia lanceolata was the smallest. The growth models of Cunninghamia lanceolata were better than those of Pinus massoniana and Pinus elliottii. (4) The higher the site quality was, the greater the maximum growth was, and the time of trees growing to the maximum growth in the higher site quality stands was shorter. In addition, in the same quality site, the growth of Pinus massoniana was the largest, followed by Pinus elliottii, Cunninghamia lanceolata. Conclusion The volume and biomass models including parameters with growth classification and stand characteristics depicts the effects of site quality on forest growth in Guangdong, which provides methodological support for accurately estimating carbon storage, and also provides a reference for the construction of stand growth models in other regions.
2022, 35(3): 103-111.
doi: 10.13275/j.cnki.lykxyj.2022.03.012
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Objective To analyze the disaster situation and factors inducing Dendrolimus superans outbreaks in Changbai Mountain Nature Reserve (CMNR). Method Sample plots in the northern slope of CMNR were investigated in 2019 and 2020, including meteorological conditions, stand structures, severity of disturbance, and forest restoration. Result The results showed that: (1) The Dendrolimus superans disturbance area was small, which occupied 12.5% of the total area of the northern slope of CMNR and of which 21.8% was mild disturbance and 79.2% was severe disturbance. The main tree species affected were Picea jezoensis, Abies nephrolepis, Pinus koraiensis, and Larix olgensis. (2) Within the disturbance area, the recovery degree of forests varied significantly among different forest types. All the disturbed Larix olgensis forests recovered, and poor recovery occurred in pure Pinus koraiensis forests and severe disturbance forests in spruce fir forests in altitude of 1 100 m to 1 300 m. (3) There were significant differences in the density of insect populations in the three types of forests because of different stand structures. Despite the high diversity and mingling degree, spruce fir forests dominated by coniferous species (pure forest) with low competition index, neighborhood comparison index, and strong tree vigor, were prone to pests disaster. The competition index and neighborhood comparison index in coniferous-broad leaved Korean pine mixed forest were high and tree vigor was weak. but the forests were dominated by broad-leaved tree species with high diversity and mingling degree, and the damage degree was lower than spruce fir forests. The competition index, mingling degree index, neighborhood comparison index, and the diversity index of Larix olgensis forests were the lowest among all three forest types. Larix olgensis was a pioneer species with small tree ages and few leaves. Although it was susceptible to insect damage, the damage degree was low due to less population densities. And leaf growth of the damaged Larix olgensis forests restored in the next year. (4) High temperature, drought, and more sunshine hours happened in 2018 and 2019. The extremely high temperature in autumn and winter of 2018 and the low precipitation in spring of 2019 were the main climatic factors for the outbreak of Dendrolimus superans. Conclusion At present, the stand structure, climatic conditions in CMNR are favorable for the outbreak of Dendrolimus superans, which indicates that Dendrolimus superans disasters will occur periodically.
2022, 35(3): 112-122.
doi: 10.13275/j.cnki.lykxyj.2022.03.013
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Objective To explore the effects of different plantations on soil physical and chemical properties under the same site conditions for providing a scientific basis for the accurate nutrient regulation and sustainable management of plantations. Methods The forests of Schima superba, Mytilaria laosensis, Nyssa sinensis and Cunninghamia lanceolata planted in 1987 on the clearcut sites of Pinus massoniana in Shatang forest farm of Liuzhou were used for analyses, and the non-forested site was used as the control. The 14 soil physical and chemical property indexes were measured in layers (0-15, 15-30, 30-50, 50-70 and 70-100 cm). Combining with KMO and Bartlett’s Test of Sphericit, principal component analysis was used for evaluating soil quality. Results In the same stand, with deepening soil layer, the soil bulk density increased, on the contrast, the contents of porosity, soil organic carbon, total N, alkali hydrolyzable N, and available P decreased. There were significant differences in soil physical and chemical properties among different stands. The soil pH values in the five stands ranged from 3.94 to 5.12. The contents of soil organic carbon, total N, alkali hydrolyzable N, available P, and the stoichiometric characteristics of C:N, C:P and N:P ratios in the broad-leaved forests were the largest, followed by coniferous forests and control stand. The total P content of soil in Cunninghamia lanceolata forest was the lowest. Compared with the control stand, the total K content of soil decreased significantly after planting forests, as well as the available K (except Mytilaria laosensis forest), indicating that the plantations have a large consumption of K element. Moreover, the contents of pH value, total K, available K, and cation exchange capacity of soil in Schima superba forest and Cunninghamia lanceolata forest were significantly lower than those in other forests and control stand. According to the principal component results, the soil quality of Mytilaria laosensis forest were the best, followed by Nyssa sinensis, Schima superba, control stand, and Cunninghamia lanceolata. Conclusion (1) Compared with coniferous forest, broad-leaved forests can accumulate soil organic carbon, N and P more effectively, and can significantly optimize soil bulk density and porosity. Broad-leaved forest should be given priority in afforestation practice in the future. (2) After 33 years of plantation, the total K content of soil is significantly lower than that of the control stand, and there are differences among different forest stands. Therefore, we should pay attention to the regulation and management of K element in forest management.
2022, 35(3): 123-130.
doi: 10.13275/j.cnki.lykxyj.2022.03.014
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Objective To identify the position and time of floral initiation and find out the relationship between the floral initiation and the growth of new shoots in Camellia Oleifera for providing a morphological basis for the study of the floral initiation mechanisms in the annual growth cycle of adult Camellia oleifera and a reference for the study of floral initiation mechanisms in perennial woody trees. Method Based on the 12-year-old Camellia oleifera (cultivar ‘changlin53’), plant anatomy and scanning electron microscopy were used to study the morphological changes of new shoots and floral buds in the process of shoot growth and floral initiation. Result Both the terminal and axillary buds of spring-shoots in Camellia oleifera were mixed buds, and the flower bud primordium located at the base of the mixed bud. The flower bud primordium formed at the terminal or axillary bud and reached the sepal differentiation stage when the spring shoots grew fast and beginning their leaves expansion. The flower bud primordium had no obvious difference from the leaf bud primordium in morphological at the sepal differentiation stage. When finishing the spring shoot leaves expansion and then arriving at the slow growth stage, the flower bud differentiation reached the petal differentiation stage. Petal was a specific organ that distinguished flower bud from leaf bud. The time of petal initiation was close to the time of finishing floral initiation in Camellia oleifera according to morphology. When spring shoots basically stopped growing and thickening, flower buds finished petal differentiation and arrived at the pistil and stamen differentiation stage. The fast growth stage, slow growth stage and finished growth stage of spring-shoots in Camellia oleifera corresponded to sepal differentiation stage, petal differentiation stage and pistil and stamen differentiation stage respectively. Conclusion The flower bud primordium of Camellia oleifera locates at the base of the mixed bud. In addition, the shoots initiation of adult Camellia oleifera are also the floral initiation in morphology.
2022, 35(3): 131-140.
doi: 10.13275/j.cnki.lykxyj.2022.03.015
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Objective To reveal community composition and distribution regularity of ants on Qinghai-Tibet Plateau, Method Distribution patterns of ant species on the northeast slope of Qinghai-Tibet Plateau were investigated through plot-sampling method. Result The result showed that a total of 30 ant species belonging to 2 subfamilies and 13 genera of Formicidae were recognized. Temperature, altitude, and vegetation types play major role in the distribution and richness of ant species. More ant species inhabited in the lower altitude zone with higher air temperature and richer food resources. Grass land had the richest ant species, and most ant species nested in the soil and foraged on the ground. Formica candida Smith had the strongest adaptability and the widest distribution range on the northeast slope of Qinghai-Tibet Plateau, and could be used as an indicator species for the ecological changes in the region. Conclusion It is concluded that most ant species have narrow distribution range and weak ecological adaptability in response to the environmental constraints, and easily become fragile due to human disturbance. Although the ant species diversity is lower, the ant species inhabiting in the region are significantly different from those of other places. Fragile ecosystem is inhabited by cold-tolerant and drought-tolerant ant species, which shows outstanding adaptability to the high-altitude oxygen-deficient environment and plays an important role in soil improvement, plant seeds dispersal, etc. in the plateau ecosystem.
2022, 35(3): 141-150.
doi: 10.13275/j.cnki.lykxyj.2022.03.016
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Objective Exploring the stand productivity in the forests with different densities and its response to climate change is helpful for the functional assessment and adaptive management of forest ecosystems. Method In this study, the net primary productivity (NPP) of natural Mongolian pine (Pinus sylvestris var. mongolica) forests with different densities (indicated by stand basal area) in the Hulunbuir Sandy Land was obtained by dendrochronology method, and its response to temperature, precipitation and drought index was analyzed. Result The results showed that the annual average NPP with stand basal area of 8.83, 21.94, 24.28, 32.36, and 34.9 m2·hm−2 were 1.17, 2.99, 3.55, 4.69, and 4.86 t·hm−2·a−1, respectively, which indicated that NPP increased with the increase of stand density. The NPP in the high-density forests were significantly positively correlated with the average temperature and average maximum temperature in July of previous year and September of the current year (P＜0.05). The precipitation in current May was the key limiting factor for the NPP. NPP in all stands was significantly positively correlated with the precipitation in current May of that year (P＜0.05). From previous November to current July, the correlation coefficient between NPP and Palmer Drought Severity Index (PDSI) decreased with increasing stand density, which indicated that the increase in stand competition led to the reduction of the sensitivity of NPP to PDSI. Conclusion Stand density has a significant impact on the NPP of natural Mongolian pine forest, as well as NPP response to climate in Hulunbuir Sandy Land. Density management may be a key measure for forest adaptive management under climate change.
2022, 35(3): 151-160.
doi: 10.13275/j.cnki.lykxyj.2022.03.017
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Objective To provide a scientific reference for the sustainable management of evergreen deciduous broad-leaved mixed forest in southwest Hubei. Method The stand spatial structure and species diversity as well as their correlations in the different spatial scales ranging from the sample size 20 m × 20 m to 200 m× 200 m in the subtropical evergreen deciduous broad-leaved mixed forests in Qizimeishan National Nature Reserve, Mulinzi National Nature Reseve and Jinzishan National forest farm in southwest Hubei province were explored. Result The tree species were abundant in this study, and Carpinus fargesiana, Cyclobalanopsis multinervis and Castanea henryi were dominant tree species. The spatial structure diversities tended to be stable when the sample size ≥ 120 m× 120 m, showing the state of micro-aggregation distribution, moderate differentiation and good mixing. The Uniform angle index was correlated with species diversity (p < 0.01) at different scales, while other structural parameters had no correlations with species diversity. Conclusion The optimum investigation scale for the stand spatial structure of subtropical evergreen deciduous broad-leaved mixed forest in southwest Hubei is 120 m × 120 m. In addition, the Uniform angle index was a key factor of stand spatial structure affecting species diversity in different spatial scales.
2022, 35(3): 161-168.
doi: 10.13275/j.cnki.lykxyj.2022.03.018
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Objective The responses of fine roots and coarse roots stoichiometric characteristics to nitrogen (N) addition were determined to reveal the difference between fine roots and coarse roots for Metasequoia glyptostroboides, which would provide theoretical guidance for understanding plant strategies under soil nutrient changing. Method We conducted a long-term N addition experiment in M. glyptostroboides plantations in Forest Farm of Dongtai City, Jiangsu Province, with four levels of N addition including control (CK, 0 kg·hm−2·a−1), low N (LN, 56 kg·hm−2·a−1), medium N (MN, 168 kg·hm−2·a−1), and high N (HN, 280 kg·hm−2·a−1). The carbon (C), N, phosphorus (P) concentrations of fine roots (diameter<2 mm) and coarse roots (2 mm≤diameter≤5 mm) and the soil physical and chemical properties were measured. Result (1) N addition significantly promoted soil organic carbon and Alkali-hydrolyzable N content, and the promotion effect weakened with the increase of N addition. (2) P concentration, C:N in both fine roots and coarse roots decreased, while N concentration, C:P, N:P increased with the increase of N addition. In addition, the response of N concentration, C:N and N:P in fine roots and coarse roots to N addition were significantly different under HN treatment, which showed the response of N concentration, C:N and N:P in fine roots to N addition weakened. (3) The plastic response of N concentration and C:N in coarse root were significantly higher than those in fine root under high N treatments. Also, the plastic response of N:P in coarse root was significantly higher than that in fine root under medium N and high N treatments. Conclusion The response of C, N, P stoichiometry in both fine roots and coarse roots to N deposition was consistent, while, plasticity response of C, N, P stoichiometry in coarse root was stronger than that in fine root under HN treatment. Overall, our findings would provide insights into the understanding of plant belowground nutrient allocation strategies under N addition, and also support for management of coastal shelterbelt.
2022, 35(3): 169-178.
doi: 10.13275/j.cnki.lykxyj.2022.03.019
Abstract:
Objective To evaluate the soil quality of different vegetation restoration measures in karst region of southeast Yunnan for providing basics for the control of rocky desertification and ecological restoration of vegetation. Method In this paper, different vegetation restoration measures in Jianshui County of Yunnan Province were carried out. The minimum data sets were established by cluster analysis and principal component analysis. The soil quality indexes of the full and minimum data set were used to evaluate soil quality. Result The results showed that: (1) There were significant differences in soil physical and chemical properties among different vegetation restoration measures (P < 0.05), which decreased with the increase of soil depth. The contents of organic carbon and available potassium in Dodonaea viscosa forest were significantly higher than those through other restoration measures. The total porosity and available potassium content of Pinus yunnanensis Franch. pure forest were lower than those through other restoration measures.(2) Quality evaluation of the minimum dataset using principal component analysis was suitable for the extraction of karst area. The minimum data set consisted of organic carbon, total nitrogen, ammonium nitrogen, total porosity, non-capillary porosity and total magnesium.(3) The soil quality of the five restoration measures was ranked as: Pinus massoniana pure forest>Dodonaea viscosa shrub forest > Natural secondary forests>Eucalyptus maideni pure forest>Pinus yunnanensis pure forest. Conclusion Pinus massoniana Lamb. are preferred species for plantation restoration in karst areas.
2022, 35(3): 179-184.
doi: 10.13275/j.cnki.lykxyj.2022.03.020
Abstract:
Objective To evaluate the population dynamics of Schima superba in Fengyangshan Mountain. Method This study established a static life table,depicted survival curves and made predictions with a time-sequence model, based on a field investigation in a 0.8ha evergreen broad-leaved forest plot. Result The age structure was in an inverse-J shape, and mainly aggregated on size class I and size class II. The population approximately tended to the Deevey-II type, which grew stably at present stage. Both the mortality and disappearance rate curves exhibited the same trend. Time sequence predictive analysis showed that the number of Schima superba individuals increased after the 2,4,6,8 size classes, the population showed an increasing trend. Conclusion The population dynamic index Vpi >0 and \begin{document}${V\,}'_{pi}$\end{document} ![]()
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2022, 35(3): 185-192.
doi: 10.13275/j.cnki.lykxyj.2022.03.021
Abstract:
Objective To accurately regulate forest structure, and effectively improve the forest quality, the structural diversities of Robinia pseudoacacia plantations in the Ancient Yellow River Course were explored, which will be helpful for ecological protection and high-quality development of the Yellow River Basin. Method Two 50 m × 100 m permanent plots (A and B) were established in R. pseudoacacia plantations in the Ancient Yellow River Course, and all the trees in the two plots were located and investigated. The bivariate distributions of DBH class and spatial parameter were used to quantitatively describe the space and size structure diversity, and the α diversity indices were used to quantify the tree size structure diversity under different spatial structures. Result The randomly distributed trees in plots A and B with 6～36 cm DBH class in the R. pseudoacacia plantations accounted for 56.2% and 52.2%, and the size diversity of randomly distributed trees in both stands were higher (\begin{document}$ {H}_{A} $\end{document} ![]()
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\begin{document}$ {H}_{B} $\end{document} ![]()
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Conclusion The space and size structure diversities of R. pseudoacacia plantation were poor, and it is urgent to make effective management measures to improve forest productivity.
2022, 35(3): 193-198.
doi: 10.13275/j.cnki.lykxyj.2022.03.022
Abstract:
Objective To accurately predict the aboveground biomass of Salix psammophila in Kubuqi Desert, the aboveground biomass models including different predictors were developed using BP neural network. Methods Six independent variables were selected and added to the biomass model according to their correlation coefficients. The number of input variables gradually increased from 1 to 6. The best BP biomass model with the optimal input variables was selected based on the model performance. Results The best structure of S. psammophila BP biomass model was that the number of input layer nodes (Nin), hidden layer nodes (Nh) and output layer nodes (Nout) were 4∶9∶1, respectively. R2, RMSE, and MAE output from training data was 0.97, 0.68, 0.50, respectively; and 0.96, 1.16, 0.78, respectively from test data. Conclusion The performance of S. psammophila aboveground biomass model based on BP neural network became better with the increasing number of input variables. However, when the number of input variables was 5, the improvement of model performance was slightly better than the model with 4 input variables. Considering the model accuracy and model application, the optimal number of input variables in the input layer is 4, and the model performance is the best when the number of hidden layers is 9.
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