Castanopsis Fargesii Research Articles

人为干扰对碧峰峡栲树次生林群落物种多样性及其优势种群生态位的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 人为干扰对碧峰峡栲树次生林群落物种多样性及其优势种群生态位的影响 DOI: 10.5846/stxb201511212361 作者: 作者单位: 四川农业大学林学院,四川农业大学林学院,四川农业大学林学院,四川农业大学林学院,四川农业大学林学院,四川农业大学林学院,四川农业大学林学院 作者简介: 通讯作者: 中图分类号: 基金项目: 四川省教育厅一般资助项目（自然科学）（15ZB0020）；国家自然科学基金资助项目（31370628）；国家“十二五”科技支撑计划资助项目（2011BAC09B05） Effects of anthropogenic disturbances on the species diversity and niche of the dominant populations in a Castanopsis fargesii secondary forest community in Bifengxia, Sichuan Author: Affiliation: College of Forestry,Sichuan Agricultural University,College of Forestry,Sichuan Agricultural University,College of Forestry,Sichuan Agricultural University,College of Forestry,Sichuan Agricultural University,College of Forestry,Sichuan Agricultural University,College of Forestry,Sichuan Agricultural University,College of Forestry,Sichuan Agricultural University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为进一步了解人为干扰对碧峰峡生态旅游区的生态环境及不同种群利用资源、占据生态空间的能力的影响，并为该区植物资源、大熊猫栖息地的保护及旅游可持续措施的制定提供依据，调查了人为干扰下碧峰峡栲树（Castanopsis fargesii）次生林物种多样性及其优势种群生态位的组成情况。结果表明：7200m2的样方中共记录到156个植物种，隶属于70科114属，其中乔木16科23属33种，灌木39科67属95种，草本38科42属47种；乔木层总体物种多样性水平在中度干扰下最低，在轻度及重度干扰下差异不大。灌木层总体物种多样性水平在中度干扰下最高，在轻度干扰下最低。而草本层物种多样性随着干扰强度的加深有明显降低趋势；随着人为干扰强度的增加，乔木层中优势种栲树的生态位宽度均为最大，与其他树种生态位重叠值在中度干扰下有所降低，枹栎（Quercus serrata）的生态位宽度会变小，山茶科（Theaceae）植物的生态位变宽，同时其生态位重叠值增大；在灌木层中，重度干扰下，菝葜（Smilax china）生态位宽度减小，栲树幼苗的生态适应范围也骤减，其他大多数物种在中度干扰下，生态位宽度最低；在草本层中，蕨类植物及皱叶狗尾草（Setaria plicata）在重度干扰下生态位宽度及重叠值均增高，其适应范围变广，种间竞争加剧。综合分析表明，群落各层次物种多样性水平对人为干扰的响应各不相同，其中人为干扰对灌木及草本层物种多样性影响最大。同时人为干扰会改变群落物种组成及种间原有的关系，特别是中度干扰会使群落间优势种地位增强，种间竞争关系加剧，导致其原有生境被破坏，不利于群落发展。因此强化景区保护及合理经营迫在眉睫。 Abstract:To further understand the effects of anthropogenic disturbances on the ecological environments and on the ability of resources utilization and ecospace occupation of the dominant population in the ecotourism area of Bifengxia, we investigated the effects of anthropogenic disturbance on the species diversity and niche of the dominant population in a Castanopsis fargesii secondary forest in this area. The results showed that a total of 156 species belonging to 70 families and 116 genera were found in a 7200 m2 quadrat. Specifically, there were 33 tree species from 16 families including 23 genera, 95 shrub species from 39 families including 67 genera, and 47 herbaceous species from 38 families including 42 genera. The level of species diversity in arborous layer was lowest under intermediate disturbance, and no obvious difference was found between communities under slight and severe disturbance. However, species diversity level in shrub layer was highest under intermediate disturbance, and lowest under slight disturbances. An obvious decrease for the level of species diversity was found in the herbaceous layer. With increase in the strength of disturbance, the niche breadth value for the dominant species (C. fargesii) in arborous layer was consistently the highest, and the value overlapping with other species decreased at certain degree under intermediate disturbance. The niche breadth value for Quercus serrata decreased, but such value for Theaceae increase as well as the overlapping value. In the shrub layer, the niche breadth value for Smilax china decreased under severe disturbance, as well as C. fargesii seedings. The niche breadth values for the majority of other species were lowest under intermediate disturbance. In the herbaceous layer, the niche breadth values and overlap values for Pteridium aquilinum var. latiusculum and Setaria plicata both increased under severe disturbance, with wider adaptive range and intensifying interspecific competition. The results suggest that anthropogenic disturbances have significant impacts on the species diversity, species status in community, and interspecific relationship in the C. fargesii secondary forest, indicating urgent measures in ecological protection and appropriate management. 参考文献 相似文献 引证文献

Completing the life history of Castanopsis fargesii: changes in the seed dispersal, seedling and sapling recruitment patterns

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.

Response of soil microbial diversity to land-use conversion of natural forests to plantations in a subtropical mountainous area of southern China

Land-use conversion can affect the soil microbial community diversity, soil organic matter and nutrient cycling. In this study, soils within a representative land-use sequence were sampled in a subtropical region of China, including four natural forests, Altingia gracilipes Hemsl. (ALG), Cinnamomum chekiangense Nakai (CIC), Castanopsis fargesii Franch. (CAF), and Tsoongiodendron odorum Chun (TSO), and two plantations, Cunninghamia lanceolata (Lamb.) Hook. (CUL) and a citrus orchard (Citrus reticulata Blanco). The soil microbial diversity was investigated by phospholipid fatty acid (PLFA) analysis, denaturing gradient gel electrophoresis (DGGE) and real-time quantitative polymerase chain reaction (PCR). Results showed that microbial community diversity exhibited distinct patterns among land-use types. After conversion of natural forests to plantations, the amount of PLFA and the number of bacterial 16 S rRNA gene copies were reduced significantly, as well as the number of DGGE bands. The average quantity of PLFA was lower by 31% in the CUL plantation and 57% in the citrus orchard, respectively, than in natural forests. Simultaneously, the average copy numbers of the bacterial 16 S rRNA gene were significantly decreased from 8.1 × 1010 g−1 dry weight (DW) in natural forest to 4.9 × 1010 g−1 DW in CUL plantation, and 3.1 × 1010 g−1 DW in the citrus orchard. Such negative responses of soil microbes to conversion of natural forests to plantations could mainly result from decreases in soil organic carbon and necessary elements for growth during land-use conversion, as revealed by statistical analysis. Our results suggested that the soil microbial diversity was indirectly influenced by land-use types in the mid-subtropical mountainous area of southern China. Changes in the amount of litterfall and the soil nutrient status that resulted from land-use conversion drove these indirect changes. Furthermore, deliberate management brought negative effects on soil microbes, which is not beneficial to the sustainability of the ecosystem.

Structure and diversity of remnant natural evergreen broad-leaved forests at three sites affected by urbanization in Chongqing metropolis, Southwest China

Evergreen broad-leaved forests (EBLFs, lucidophyllous forests) are vegetation types characteristic of East Asia. The extent of EBLFs has decreased significantly due to long-term anthropogenic disturbance, and remnant EBLFs in urban area are rare and important landscape types contributing to biodiversity and sustainable development. This study focuses on remnant EBLFs on Mt. Gele (GL), Mt. Tieshanping (TSP), and Mt. Jinyun (JY), located from the inner city to outskirts of Chongqing metropolis, Southwest China. Species of Theaceae, Lauraceae, Symplocaceae, and other families, which are essential floristic components of primary EBLFs, were still the main components at the three sites. GL and JY showed higher biodiversity, with richer heliophytes and shade-tolerant species, respectively. Castanopsis carlesii var. spinulosa was the sole dominant species at all three sites in woody layer, with codomination by Pinus massoniana and Cinnamomum camphora at GL and by Machilus pingii and Castanopsis fargesii at JY; these evergreen broad-leaved trees all showed inverse-J or sporadic-shaped size distribution with large numbers of small stems, but the conifer tree Pinus massoniana showed unimodal distribution with small stems at GL. The height growth of tree species, especially Castanopsis carlesii var. spinulosa, was increasingly restricted from JY to TSP to GL. Sprouting is an important life history strategy at community and population level, and differences were exhibited from GL to TSP to JY. A rural–urban gradient from JY to TSP to GL was indicated in this study. Species composition, biodiversity, and stand structure of these remnant EBLFs showed obvious differences along this gradient, and conservation responses to address the effects of urbanization need to be carefully considered.

Shifts in plant nutrient use strategies under secondary forest succession

In evergreen broad-leaved forests (EBLFs) in Tiantong National Forest Park, Eastern China, we studied the soil chemistry and plant leaf nutrient concentration along a chronosequence of secondary forest succession. Soil total N, P and leaf N, P concentration of the most abundant plant species increased with forest succession. We further examined leaf lifespan, leaf nutrient characteristics and root–shoot attributes of Pinus massoniana Lamb, the early-successional species, Schima superba Gardn. et Champ, the mid-successional species, and Castanopsis fargesii Franch, the late-successional species. These species showed both intraspecific and interspecific variability along succession. Leaf N concentration of the three dominant species increased while N resorption tended to decrease with succession; leaf P and P resorption didn’t show a consistent trend along forest succession. Compared with the other two species, C. fargesii had the shortest leaf lifespan, largest decay rate and the highest taproot diameter to shoot base diameter ratio while P. massoniana had the highest root–shoot biomass ratio and taproot length to shoot height ratio. Overall, P. massoniana used ‘conservative consumption’ nutrient use strategy in the infertile soil conditions while C. fargesii took up nutrients in the way of ‘resource spending’ when nutrient supply increased. The attributes of S. superba were intermediate between the other two species, which may contribute to its coexistence with other species in a wide range of soil conditions.

Spatial and temporal variation of seed predation and removal of sympatric large-seeded species in relation to innate seed traits in a subtropical forest, Southwest China

Based on the complex seed packaging strategies involving morphology, nutrition quality and secondary chemistry, spatial and temporal variation of seed predation and removal by granivorous rodents was examined among six sympatric large-seeded tree species with different seed traits: Lithocarpus harlandii, Quercus variabilis, Q. serrata, Cyclobalanopsis glauca and Castanopsis fargesii (Fagaceae); Camellia oleifera (Theaceae) across different stands and seasons in a subtropical evergreen broadleaved forest, Southwest China. The smallest seeds of Castanopsis fargesii with lower tannin concentration, L. harlandii with the largest seed size and Camellia oleifera with high fat concentration, were harvested more quickly than the apparently less preferred seeds of Q. variabilis, Q. serrata and C. glauca with higher tannin concentration. Larger ( L. harlandii and Q. variabilis) or high fat seeds ( Camellia oleifera) have higher levels of removal and lower levels of instant consumption than smaller seeds ( Castanopsis fargesii, Q. serrata and C. glauca) for both stand and season. Results showed that high fat or large seeds are harvested more quickly than small or medium seeds with high tannin concentration, and that high fat or large seeds are also more likely to be removed than small or medium seeds with high tannin concentration. Moreover, seed predation and removal are consistent among stands and seasons. Innate seed traits are shown to be important in determining whether a given seed is eaten or removed when rodents are provided uniform number of seeds with differing traits. The hierarchical preference for larger or high fat seeds is maintained when background seed abundance varies in time and space.

Effects of seed size on dispersal distance in five rodent-dispersed fagaceous species

We studied the effect of seed size on dispersal by comparing dispersal distances in five rodent-dispersed fagaceous species (Lithocarpus harlandii, Quercus variabilis, Q. serrata, Cyclobalanopsis glauca, Castanopsis fargesii) with different seed size. We tracked individual seeds with coded tin-tags in two stands over 3 years in a subtropical evergreen broadleaved forest in the Dujiangyan Region of Sichuan Province, Southwest China. Our seed tracking data indicate that dispersal distances (including mean, maximum and distribution range) of seeds in primary caches and of seeds eaten after dispersal significantly increased with seed size, for both stands and all years. In addition, larger seeds (L. harlandii and Q. variabilis) were re-cached more often than smaller ones, which further reduced the relative density among caches and extended dispersal distances. Our findings indicate that greater dispersal distances for larger seeds might benefit the evolution of differences in seed size, and that scatter-hoarding might be advantageous for rodent-dispersed tree species.

The effects of seed abundance on seed predation and dispersal by rodents in Castanopsis fargesii (Fagaceae)

Based on the animal dispersal hypothesis and the predator satiation hypothesis, we examined the effects of seed abundance at both population (i.e., mast seeding) and community levels on seed predation and dispersal of Castanopsis fargesii (Fagaceae), a rodent-dispersed mast species in Eastern Asia. In a subtropical evergreen broadleaved forest in the Dujiangyan region of Sichuan Province, China, individual seeds with coded tin tags were tracked in two contrasting stands (seed-poor and seed-rich) over two years (2000, a low-seed year; 2001, a high-seed year). Our results showed that: (1) small rodents did not harvest the tagged seeds of C. fargesii more rapid in the high-seed year than in the low-seed year in either stand. But, seed harvest was significantly faster in the seed-rich stand than in the seed-poor stand. (2) The removal proportion was significantly lower in the high-seed year than in the low-seed year for either stand, but the removal proportion was slightly higher in the seed-poor stand than in the seed-poor stand. This indicates that high seed abundance decreases seed removal (predator satiation hypothesis). (3) There were only small differences about seed caching, seed survival and seedling establishment of C. fargesii between years and stands. During the survey, no cached seeds survived to geminate in the spring for both stands and years. (4) Mean dispersal distances of the cached seeds are much shorter in the high-seed year (3.1 m) than in the low-seed year (8.1 m) in the seed-rich stand, though similar trend is not examined in the seed-poor stand. Our results indicate that seed predation and dispersal of C. fargesii are influenced by both mast seeding and community-level seed abundance, which is not completely consistent with either the animal dispersal hypothesis or the predator satiation hypothesis, but seems more related to the predator satiation hypothesis.

Flowering Phenology and Floral Distribution of Castanopsis fargesii in Tiantong, Zhejiang Province

Forested areas of eastern China are predominatly evergreen broad_leave d forests which are typically zonal or climatic climax vegetation in subtropical areas, dominated by Castanopsis fargesii Franch. (Fagaceae),a shade_toler ant an d long_lived species. The observation and study of its reproductive characterist ics in the field still remain poorly understood. Based on the methods of Randomi zed Branch Sampling and observation of labeled individuals, the flowering phen ol ogy, flower number and spatial distribution of Castanopsis fargesii Franch. from the Schimeto_Castanopsietum fargesii Association in the Tiantong National F ores t Park (TNFP) were studied in this paper. The results showed that the floral bud flushing and inflorescence elongation of C. fargesii emerged at end of Apri l an d the trees flowered after leaf emergence. The onset of mass flowering occurred at late May, and its duration within population could last more or less eight d ays, while the flowering time among individuals experienced less difference. The refore C. fargesii displays synchronous flowering. Given the lower precipit ation and gradually increasing temperature during April_May, synchronous floweri ng and therefore pollination in C. fargesii is a beneficial adaptation. Floral buds commonly located at the first_order branch, which made up 91. 92% of all the reproductive branch, nearly 7.07% and 1.01% at the second and th e third branch, respectively. There was an apparent difference between the flora l bud initiation at the toward_sun reproductive branch and the toward_shade ones within a crown (p0.01) and the floral bud initiation were 78%±5.7% and 67 %±5.7% respectively. Within a crown, there were about 4.89±1.82 panicles per reproductive branch at sun_side and 3.08±2.08 at shade_side. The number of male inflorescence of C. fargesii is more than that of the fem ale and male inflorescence occupied 77.9% of the total and female inflorescence 22.1 % respectively. There were 67.9±16.7 staminate at one male inflorescence and 2 6.1±5.08 pistillate at one female inflorescence. Furthermore, the flower number s were male biased during spring censuses and the ratio of staminate to pistilla te was about 9.2∶1. Mass staminate could produce higher pollen concentration du r ing synchronous period and should increase the pollination efficiency. Therefore flowering in spring exerted great influence on the reproductive output of C. fargesii.

Interactive effects of season and light environment on growth and leaf dynamics of evergreen tree seedlings in the humid subtropics

Interactive effects of season and light environment on tree seedling growth were studied in four evergreen species in the humid subtropics of China. These species were the needle-leaved pioneer Pinus massoniana and the broad-leaved shade-tolerant Castanopsis fargesii, Sloanea leptocarpa, and Elaeocarpus japonicus. The experimental outdoor light environments, which broadly simulated those in forest gaps and clearings, were 100, 55, 33, and 18% of incident light quantity. Mean relative growth rates for both total leaf area and s tem height revealed interaction of season and light environment in Pinus, Castanopsis, and Elaeocarpus. In these species, mean relative growth rates were higher in summer in more shaded environments and in autumn in more exposed environments, but this shift was not as clear in Castanopsis. Winter growth was virtually nil in all species, although Pinus still achieved some winter stem height change. The hypothesis that late-successional rather than early-successional species would demonstrate interactions of season and light environment on growth and development was not sufficiently supported by the data. Variation in mean relative growth rates for total leaf area was due to changes in whole-plant average leaf size as well as leaf numbers. In Sloanea and Elaeocarpus seedlings in high light environments, reduced leaf size and enhanced leaf abscission rates gave rise to negative mean relative growth rates for total leaf area. The more sun-tolerant Castanopsis seedlings revealed no such leaf size response and shed few, if any, leaves in any of the light environments. These results indicate that seasonal variability in the growth response of tree seedlings to the light environment is an important factor to be taken into account in studies on gap dynamics of subtropical forests. Keywords: China, leaf area, leaf turnover, leaf size, mean relative growth rate, shade, subtropical, sun.

Effects of canopy gaps on the growth of tree seedlings from subtropical broad-leaved evergreen forests of southern China

Seedling performance, morphology, and leaf characteristics of evergreen tree species from different successional stages of Chinese broadleaved evergreen forests were studied in four simulated gap environments: in 100, 55, 33, and 18% of full sunlight. The first two represent the light regimes of clearings (gaps secondarily become more open due to human activity and natural erosion). The hypothesis was tested that early-successional species achieve their greatest seedling size in clearings and contrast in this respect with late-successional species. Late-successional species were expected to show a stronger morphological response (leaf/root ratio) to clearings than early-successional ones. The results provided some evidence in support of these hypotheses with one exception, namely that late-successional Castanopsis fargesii appeared to be a highly sun-tolerant species. It is suggested that Castanopsis seedlings are competitive in large gaps and clearings.

Aboveground Morphology of Shade-Tolerant Castanopsis fargesii Saplings in Response to Light Environment

Branching pattern and intensity, aboveground biomass partitioning, and leaf display in response to light environment were studied in saplings of the shade-tolerant broad-leaved evergreen tree Castanopsis fargesii. Relative light exposures corresponded with those in forest gaps and clearings: 18%, 33%, 55%, and 100% full sunlight. At 18% full sunlight saplings had comparatively long main stems and long, sparsely bifurcating first-order lateral axes (as counted centrifugally). In more exposed environments saplings developed shorter first-order lateral axes that supported larger numbers of higher order axes of greater total length and weight. These saplings had relatively small leaves in high densities. The differences in aboveground morphology were partly due to variability in overall plant size and were partly a direct effect of light environment. The different crown shapes and foliage densities were considered adaptive in the different light environments. The favorable growth and morphological responses of the saplings to high light environments indicate that C. fargesii is a competitive species in large gaps and clearings.