首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Conservation and sustainable forestry are essential in a multi-functional landscape. In this respect, ecological studies on epiphytes are needed to determine abiotic and biotic factors associated with high diversity. The aim of the present study was to evaluate relative sensitivity of conservation targets (epiphytic bryophytes and lichens) in relation to contrasting environmental variables (tree species, tree diameter at breast height, bark crevice depth, pH, tree inclination, pH, forest stand age, area and type) in boreo-nemoral forests. The study was conducted in Latvian 34 woodland key habitat (WKH) boreo-nemoral forest stands. Generalized linear mixed models and canonical correspondence analysis showed that tree species and tree bark pH were the most important variables explaining epiphytic bryophyte and lichen composition and richness (total, Red-listed, WKH indicator species). Forest stand level factors, such as stand size and habitat type, had only minor influence on epiphytic species composition and richness. The results of the present study indicate a need to maintain the diversity of tree species and large trees, particularly Acer platanoides, Carpinus betulus, Fraxinus excelsior, Populus tremula, Tilia cordata, Ulmus glabra and Ulmus laevis in conservation of epiphytic bryophyte and lichen communities in the future.  相似文献   

2.
The introduced tree species Spathodea campanulata (Bignoniaceae) forms novel forests in Puerto Rico, these having emerged after the abandonment of fields in the mid‐20th century and resulting in forests with a new species composition. We assessed bryophyte species richness in these novel forests and sought correlations with geological substrate, past land use, forest edge and patch area, forest structure, elevation, microhabitat diversity, tree species richness, and microclimatic conditions. Transects were established (edge and forest interior) in nine moist forest patches dominated by Spathodea in north‐central Puerto Rico. These Spathodea forest patches ranged from 0.6 to 9 ha. ANOVA, Chi‐square, correlation, and cluster analyses were used in data analyses. We found 57 bryophyte species. There was a significant difference in bryophyte richness among patches. Those on karst exhibited highest bryophyte richness due to microhabitat diversity, past land use, and shorter hydroperiods. Alluvial sites scored lowest in bryophyte species richness, and forest structure was important for bryophyte communities on these sites. Significant differences in temperature, relative humidity, and light intensity were observed between edge and forest interior. These appeared important for establishing bryophyte species cover but not richness and composition. Microhabitat diversity, patch area, and forest age were more related to bryophyte species richness than elevation, exposed edge, and tree species richness, regardless of geologic substrate. Collectively, Spathodea patches were similar to mature forests on the Island with respect to bryophyte species richness and composition. Novel Spathodea forests have conservation value due to their habitat suitability for bryophyte communities.  相似文献   

3.
Residual patches of forest remaining after natural or anthropogenic disturbance may facilitate regeneration of fragmented forest. However, residual patch function remains unclear, especially after natural wildfire. We investigate the role of residual boreal forest patches as refugia for bryophytes and ask the question, do they house bryophyte communities similar to those encountered in undisturbed forests? Bryophytes were sampled in three habitat types in black spruce boreal forests illustrating a gradient of disturbance severity: undisturbed forests, residual patches and burned matrices. Temporal, disturbance severity, spatial and structural variables of habitats were also recorded. Bryophyte community composition differed among habitat types with residual patches characterized by higher species richness, the loss of forest specialists and the addition of disturbance-prone species. The bryophyte community found in residual patches is at the interface between the communities of undisturbed forests and burned matrices. As residual patches did not conserve all species, particularly forest specialists, they were not refugia. However, we identify temporal, spatial and structural characteristics that can maintain bryophyte communities most similar to undisturbed forests and enhance residual patch “refugia potential”. Residual patches enhance bryophyte diversity of the landscape housing species that cannot survive in the burned matrix. As conclusion we discuss the use of retention patches in harvested stands, together with the preservation of undisturbed stands that house singular bryophyte communities and especially sensitive forest specialists.  相似文献   

4.
In many dioecious bryophyte species, population sex ratios range from all female to all male. The focal species of the present study, the liverwort Marchantia inflexa, forms patches on rock and bark surfaces, and these differ widely in sex ratio at a rainforest field site in Trinidad. This analysis – to our knowledge the first modeling study of sex-ratio dynamics in a dioecious clonal organism – addresses abundances of male and female M. inflexa through time within an individual patch. We represent the life history of this species using seven different stages (non-reproductive, asexually reproductive, sexually reproductive males, non-reproductive, asexually reproductive, unfertilized and fertilized sexual females) and express their dynamics using ordinary differential equations. Some of the stages become more abundant as thalli extend over the substrate and may overgrow each other to capture space. Our simple representation of dynamics within the patch failed to stabilize the sex ratio: females gradually eliminated males at low to moderate disturbance frequency and males eliminated females at high disturbance frequency. This pattern did not hinge on whether sexual propagules could germinate within the patch, but asexual reproduction (via gemmae dispersed within the patch) played an important role. This suggests that the maintenance of sex in these populations may hinge on metapopulation structure and dynamics. Though sexual reproduction appears to be unimportant within patches, spores provide the primary means of recolonizing patches eliminated by large-scale disturbances. We found that shortly after the patch was fully occupied, the production of these wind-dispersed spores was maximized, but spore production declined thereafter as the sex ratio became increasingly biased toward one sex or the other. Much additional modeling and empirical work is needed to link within-patch dynamics across patches and account for dynamics at the metapopulation level.  相似文献   

5.
Patterns of moss and liverwort species diversity — species richness and species turnover (β‐diversity) — in three conifer‐dominated boreal forest stands of northern Alberta, Canada are described. We examined the relationship between bryophyte species diversity and micro‐environment at two sample grains, the microsite — substrate types for moss colonization: logs, stumps, tree bases, undisturbed patches of forest floor (dominated by feather moss species), and disturbed patches of forest floor — and the mesosite (25 m × 25 m plots). Microsite type and properties (e.g. decay class, hardwood vs softwood, pH) were the principal predictors of bryophyte species diversity and not micro‐environment variation among mesosites. Microsite type was the strongest predictor of microsite species richness and β‐diversity was higher among microsites and types and within microsites than among mesosites or stands. Microsite properties were significant predictors of species richness for all microsite types. Log and stump decay classes, influenced also by hardwood vs softwood predicted species richness of woody microsite types and soil pH and moisture predicted species richness of forest floor microsites. β‐diversity was highest for tree bases and disturbed patches of forest floor and lowest for logs. Mesosite β‐diversity was lower than that among microsites, and mesosite species richness was not well explained by measured environmental parameters. Results suggest that in conifer‐dominated boreal stands, species richness of microsites is only negligibly influenced by within‐stand variation at the mesosite grain and that substrate characteristics are the most important predictors of bryophyte species diversity in this ecosystem.  相似文献   

6.
The spatial pattern and occurrence of a threatened bryophyte, Neckera pennata. were studied in relation to the abundance and pattern of suitable substrate trees at two spatial scales: 1) in a 4 x 4 km fraction of fragmented, mostly managed southern boreal forest landscape, and 2) in an old-growth forest stand within this landscape, with abundant occurrence of suitable habitats. To explore in detail the spatial clustering of N. pennata at the forest stand scale, we applied a second order point process analysis based on the Ripley's K-function for binary point patterns, Neckera pennata proved to be a rare species in the studied landscape: it was found only on 31 Populus tremula trees. At the landscape scale, the distribution of the species was highly aggregated: the species occurred only within a 60 ha old-growth forest patch in the whole area. At the forest stand scale, N. pennata proved to be a widespread, randomly distributed species without any tendency towards aggregation. It was found on 19 Populus trees, which was only 1.5% of the total 1253 potential substrate trees within the inventory area. The species showed a statistically significant preference towards large trees. The future of the species in the study area is unclear due to 1) the very low population density and 2) the lack of regeneration of Populus within the protected old-growth forest area hosting the remaining population.  相似文献   

7.
研究比较了南亚热带6年生格木(Erythrophleum fordii)、马尾松(Pinus massoniana)幼龄人工纯林及马尾松与格木混交林生态系统碳氮储量及其分配特征。结果表明,生态系统总碳储量依次为马尾松-格木混交林(137.75 t/hm2)格木纯林(134.07 t/hm2)马尾松纯林(131.10 t/hm2),总氮储量则为格木纯林(10.19 t/hm2)马尾松-格木混交林(8.68 t/hm2)马尾松纯林(7.01 t/hm2)。3种人工林生态系统碳氮库空间分布基本一致,绝大部分储存于0—100 cm土壤层,平均占生态系统总储量的81.49%和96.91%,其次为乔木层(分别占17.52%和2.69%),林下植被和凋落物层所占比例最小。林地土壤碳主要集中于表土层,其中0—30 cm土层平均碳储量为52.52 t/hm2,占土壤总碳储量(0—100 cm)的47.99%,土壤氮的分布则无明显规律。相比于纯林,与固氮树种混交的营林方式表现出更大的碳储存能力。3种幼龄人工林生态系统较低的地上与地下部分碳氮分配比,表明其仍具有较强的碳氮固持潜力。  相似文献   

8.
王晓荣  曾立雄  雷蕾  潘磊  肖文发 《生态学报》2019,39(12):4421-4431
探讨不同抚育择伐方式下森林群落物种空间分布格局和关联性,对科学优化森林结构和促进森林稳定发展具有重要意义。以三峡库区马尾松飞播林为研究对象,采用未择伐、伐除优势马尾松、伐除非马尾松、除灌等处理方式建立固定监测样地,利用Ripley′s L函数的空间点格局方法,分析抚育择伐3年后马尾松林的群落组成、空间分布格局、种间关联性的变化特征。结果表明:1)不同抚育择伐措施均在一定程度上改变了物种组成以及部分树种的优势程度,降低了各样地乔木层物种多样性。2)未择伐主要树种空间分布格局以随机分布为主,伐除优势马尾松样地优势树种主要呈现聚集分布,伐除非马尾松改变了香椿和盐肤木等树种的分布格局,呈聚集分布,其他优势树种空间分布格局与对照样地相似;除灌进一步加剧林下更新树种的随机分布。3)未择伐样地主要树种空间关联性表现为正相关或不相关,伐除优势马尾松增加了主要树种间的负相关性,伐除非马尾松和除灌措施则增加了种间的不相关性。短期人为择伐干扰明显改变了林分空间结构和稳定性,择伐对象不同对林分结构产生的影响也不同。单纯调整某个树种或单个层次的结构来开展森林经营,不利于林分空间结构的整体优化,必须要综合考虑择伐强度和择伐对象的选择,将有助于实现森林结构优化和功能提升。  相似文献   

9.
Mound‐building ants (Formica spp.), as key species, have large impacts on organisms and ecosystem functions in boreal Eurasian forests. The density, sizes and locations of ant mounds determine the magnitude and the spatial distribution of ant activities in forest ecosystems. Clear‐cutting can destroy wood ant colonies, and the species, abundance, dimensions and locations of ant mounds may change as forest stand structure changes with stand age. We compared ant species composition, ant mound numbers and dimensions, and the spatial distribution of mounds in Norway spruce [Picea abies (L.) Karst.] stands of different age (5, 30, 60 and 100 years) in eastern Finland. The mound density of Formica aquilonia Yarr. was greater in the two oldest stand age classes, while most mounds of Formica rufa L., Formica polyctena Först., Formica lugubris Zett., Formica exsecta Nyl. and Formica pressilabris Nyl. were found in the two youngest age classes. The mean volume, the volume per area and height/diameter ratio of F. aquilonia mounds increased with stand age. In the oldest stand age class, mounds were slightly smaller in well‐lit locations than in shade and near stand edges than further from the edges indicating that new mounds are established in well‐lit locations. Similarly, the longest slopes of the mounds faced south, indicating the importance of exposure to the sun. F. aquilonia mounds were concentrated near stand edges, and the spatial distribution of the mounds was aggregated in some stands. At the ecosystem level, the aggregation of ant mounds near stand edges may increase the edge productivity, as mounds concentrate resources to the edges and release nutrients after abandonment.  相似文献   

10.
红脂大小蠹种群空间格局地统计学分析及抽样技术   总被引:3,自引:0,他引:3  
红脂大小蠹是我国一重要林业外来入侵害虫,主要危害油松、白皮松和华山松,目前已扩散到山西、陕西、河北、河南、北京等地。为了研究其种群空间格局,用地统计学方法分析了受害程度不同的油松纯林和混交林林分内红脂大小蠹种群空间分布特性。结果表明:两种受害程度不同的油松纯林内红脂大小蠹的危害具有显著差异,轻度受害林分内有虫株率为4.9%,而重度受害林分则达到23.6%。全方向的变异函数曲线图分析得知:轻度受害纯林、重度受害纯林、混交林林分内红脂大小蠹种群的空间依赖范围分别为49.400、47.400\,73.820m,而局部空间连续性强度分别为0.824、0.582\,0.762。轻度受害纯林与重度受害纯林林分内红脂大小蠹种群均表现为较强的空间聚集性,而混交林受害林分内其种群则表现为随机分布。受害程度不同的纯林林分内红脂大小蠹种群空间格局具有一定的差异,而且纯林与混交林林分内其种群空间格局也有较大的差别。本文根据红脂大小蠹种群空间分布特性,对其种群空间抽样技术与传统抽样技术做了相应的比较与探讨。  相似文献   

11.
不同强度火干扰下盘古林场天然落叶松林的空间结构   总被引:4,自引:0,他引:4  
倪宝龙  刘兆刚 《生态学报》2013,33(16):4975-4984
基于2011年7月大兴安岭外业调查数据以林隙为主要研究对象,选取景观生态学中斑块类型指数分析样地内林隙状况,并结合林木分布状态,分析不同强度林火干扰对天然落叶松林空间结构的影响。结果表明:在受中度林火干扰的林分内,只保留了少量的落叶松中径木、大径木,先锋树种在林分内呈现聚集分布;在未受林火干扰的林分和受林火轻微干扰的林分内,天然落叶松均呈现显著聚集分布;由于受到不同强度的林火干扰,林下区域与林隙区域出现不同程度的相互转化,林分空间结构发生了改变。林分按照所受林火干扰强度的递减,在同一时间不同空间上表现出了森林循环过程中所经历的林隙阶段状态、建立阶段状态、成熟阶段状态。  相似文献   

12.
  1. Pure forests are often seen as being more prone to damage by specialist pest insects than mixed forests, and particularly mixed forests associating host and nonhost species. We addressed the effect of tree diversity on oak colonization and defoliation by a major specialist pest, the oak processionary moth (OPM)
  2. We quantified the number of male OPM moths captured and larval defoliation in pure stands of two oak host species (Quercus robur and Quercus petraea) and in mixed stands associating the two oak species or each oak species with another nonhost broadleaved species. We conducted two complementary studies to test the effect of host species and stand composition: (i) we used pheromone trapping to compare the number of males OPM captured throughout the distribution of oak hosts in France and (ii) we noted the presence of OPM nests and estimated defoliation in mature forests of north‐eastern France.
  3. Oak species and stand composition significantly influenced the number of male OPM captured and defoliation by OPM larvae. Quercus petraea was consistently more attractive to and more defoliated by OPM than Q. robur. Both oak trees were attacked more in pure stands than in mixed stands, in particular mixed stands associating oaks with another (nonhost) broadleaved species.
  4. The results of the present study support the view that mixed forests are more resistant to specialist pest insects than pure stands, and also indicate that this trend depends on forest composition. Our study provides new insights into OPM ecology and has potential implications for forest management, including the management of urban forests where OPM causes serious human health issues.
  相似文献   

13.
This study explores the host tree preferences of epiphyte bryophyte communities in two key types of evergreen cloud forests on La Gomera (Canary Islands, Spain): ericaceous versus broadleaved laurel forest. By comparing two pairs of tree species (Erica arborea and Myrica faya vs. Ilex canariensis and Laurus novocanariensis) that occur in both forest types, we quantitatively examined whether epiphyte-host relationships change with the type of forest. In 51 ancient forest stands, the low-trunk bryophyte composition on the two host tree groups was analysed with both non-parametric procedures and ordination analyses. Our results highlight that the influence of local environmental conditions on the structuring of epiphyte communities may be different depending on the host tree identity. Whilst the epiphyte composition of the host tree group formed by I. canariensis and L. novocanariensis differed significantly between forest types depending on solar exposure, we failed to find variations for the other host tree group, excepting in those localities wherein mist precipitation was extremely high. Our findings highlight the importance of the natural diversity of tree species along environmental gradients, as well as of water availability at different spatial scales for epiphytic bryophytes in montane cloud forests.  相似文献   

14.

Cryptogamic diversity is a reliable indicator of the state of forest ecosystems. In this study we analysed the variations in both bryophyte species richness overall and number of hemerophobic bryophyte species in Central European managed forests over a 20-year time span, based on data collected in 132 plots scattered across Poland. We tested differences in species richness among five temporal replicates, as well as among site types grouped based on elevation a.s.l., dominant tree species and stand age. The analyses revealed no significant trend in species richness across years. Meanwhile, species richness significantly increased along with elevation a.s.l., especially in broadleaved forests. No significant difference in species number between spruce and pine dominated stands emerged for mature stands, while there was a strong difference for young stands, with spruce forest hosting a much higher number of species. Species richness exhibited a slight, but not significant, increase over time in broadleaved forests, no significant variations in pine dominated stands and significant fluctuations in spruce dominated stands, yet without a significant trend. Out of the tested drivers, dominant tree species exhibited the strongest impact on species community composition. Number of hemerophobic and strongly hemerophobic species did not undergo significant variations across years either. The lack of bryophyte diversity trends highlighted in this study suggests Central European managed forests are in an equilibrium sate, maintained by the opposing effects of climate changes, on one side and of more sustainable forest management and pollutant deposition decline, from the other.

  相似文献   

15.
16.
The bryophyte vegetation of 3 pairs of unmanaged and managed forest stands, representing Oxalis drained peatland, Aegopodium and Oxalis forest site type, were compared. The total number of bryophyte species in unmanaged stands was 74 and that in managed stands 54. Out of the 20 species occurring only in unmanaged forests, 9 grow on decaying wood, and 3 on trunks or bases of big trees; 13 of them were hepatics. In unmanaged forests 11 hemerophobic species were recorded altogether. Although the difference in substrate and species diversity between unmanaged and managed stands is not statistically significant, in unmanaged forests more substrates characteristic for an old-growth stand are available, and the percentage of species preferring dryer habitats or prolonged humidity is a bit higher than in managed forests; the percentage of species associated with better illuminated habitats is higher in managed forests. Analysis of classification structure of the bryophyte layer synusia shows that the number of societies is also higher in unmanaged forests. This is associated with more numerous microhabitats; the average light and humidity indices calculated for every society, confirm this conclusion. The large discrepancy in bryophyte layer classification structure in old-growth and managed forests of the same forest site type is manifested not so much by species content in synusia as by their abundance proportions. The larger diversity of classification units in unmanaged forests is also seen at the synusia facies level; four of nine facies are confined exclusively to unmanaged stands. This is a strong argument for the informativeness of bryophyte layer classification structure for purposes of indication and monitoring as well.  相似文献   

17.
The objective of this study was to quantify carbon (C) distribution for boreal black spruce (Picea mariana (Mill.) BSP) stands comprising a fire chronosequence in northern Manitoba, Canada. The experimental design included seven well‐drained (dry) and seven poorly‐drained (wet) stands that burned between 1998 and 1850. Vegetation C pools (above‐ground + below‐ground) steadily increased from 1.3 to 83.3 t C ha?1 for the dry chronosequence, and from 0.6 to 37.4 t C ha?1 for the wet chronosequence. The detritus C pools (woody debris + forest floor) varied from 10.3 to 96.0 t C ha?1 and from 12.6 to 77.4 t C ha?1 for the dry and wet chronosequence, respectively. Overstorey biomass, mean annual biomass increment (MAI), woody debris mass, and litterfall were significantly greater (α = 0.05) for the dry stands than for the wet stands, but the bryophyte, understorey, and forest floor C pools were significantly less for the dry than for the wet stands. The root mass ratio decreased with stand age until 37 years after fire, was fairly constant thereafter, and was not significantly affected by soil drainage. The C pools of the overstorey and bryophyte tended to increase with stand age. Foliage biomass, litterfall, and MAI (for the dry stands) peaked at 71 years after fire and declined in the oldest stands. The results from this study illustrate that the effects of disturbance and edaphic conditions must be accounted for in boreal forest C inventories and C models. The appropriateness of using chronosequences to examine effects of wildfire on ecosystem C distribution is discussed.  相似文献   

18.
Fire is the prevalent disturbance in the Araucaria–Nothofagus forested landscape in south‐central Chile. Although both surface and stand‐replacing fires are known to characterize these ecosystems, the variability of fire severity in shaping forest structure has not previously been investigated in Araucaria–Nothofagus forests. Age structures of 16 stands, in which the ages of approximately 650 trees were determined, indicate that variability in fire severity and frequency is key to explaining the mosaic of forest patches across the Araucaria–Nothofagus landscape. High levels of tree mortality in moderate‐ to high‐severity fires followed by new establishment of Nothofagus pumilio typically result in stands characterized by one or two cohorts of this species. Large Araucaria trees are highly resistant to fire, and this species typically survives moderate‐ to high‐severity fires either as dispersed individuals or as small groups of multi‐aged trees. Small post‐fire cohorts of Araucaria may establish, depending on seed availability and the effects of subsequent fires. Araucaria's great longevity (often >700 years) and resistance to fire allow some individuals to survive fires that kill and then trigger new Nothofagus cohorts. Even in relatively mesic habitats, where fires are less frequent, the oldest Araucaria–Nothofagus pumilio stands originated after high‐severity fires. Overall, stand development patterns of subalpine AraucariaN. pumilio forests are largely controlled by moderate‐ to high‐severity fires, and therefore tree regeneration dynamics is strongly dominated by a catastrophic regeneration mode.  相似文献   

19.
We studied regeneration patterns of three tree species Picea ajanensis, Betula platyphylla and Populus tremula from 1998 to 2000 in the Central Depression of the Kamchatka Peninsula. We paid special attention to the contribution of sprouting to their regeneration. P. ajanensis was the only species that regenerated by seedling. In a 40 × 40 m study plot, the density of P. ajanensis saplings < 2.0 cm in diameter at basal area (DBH) was 1132, and this was the highest among the three species studied. The number of saplings 2 cm in DBH declined sharply with size class. The spatial distribution of P. ajanensis saplings (< 2 cm in DBH) showed a significant positive correlation with that of adult trees and a negative correlation with that of gaps. These trends were not changed after re-measurement in 2000, although nearly half of the juveniles had died or been injured during the two years. These results suggest that small Picea saplings prefer habitats under the canopy of adult trees rather than in gaps for establishment. Most small individuals of B. platyphylla were produced from sprouts. The number of saplings in the smallest size class (< 2 cm in DBH) was much less than that of P. ajanensis, although the number of larger individuals did not decrease remarkably. The spatial distribution of B. platyphylla saplings showed a positive correlation with that of adult trunks and a negative correlation with that of canopy trees of P. ajanensis. These results suggest an effective contribution of sprouts to the regeneration of B. platyphylla. P. tremula was the only species that could invade big gaps and produce many root suckers efficiently. There were 181 suckers of P. tremula in the smallest size class (< 2 cm in DBH) in the study plot, although the number of saplings 2 cm in DBH declined abruptly. The spatial distribution of saplings of this species showed a slight positive correlation with that of gaps, and negative correlation with that of adult trees of B. platyphylla, P. ajanensis, and P. tremula. The root suckering strategy of P. tremula might be adaptive under severe conditions in high-latitude regions. Our data suggest, however, that it does not necessarily contribute to regeneration in mature forests. The three component species in this forest did not seem to utilize canopy gaps for regeneration; we suggest that gap dynamics do not work in this forest. The sparse canopy, which is a typical character of forests in high-latitude regions, might be a consequence of high mortalities of seedlings and root suckers inside gaps.  相似文献   

20.
Many factors associated with forests are collectively responsible for controlling ectomycorrhizal (ECM) fungal community structure, including plant species composition, forest structure, stand age, and soil nutrients. The objective of this study was to examine relationships among ECM fungal community measures, local soil nutrients, and stand age along a chronosequence of mixed forest stands that were similar in vegetation composition and site quality. Six combinations of age class (5-, 26-, 65-, and 100-year-old) and stand initiation type (wildfire and clearcut) were replicated on four sites, each representing critical seral stages of stand development in Interior Cedar-Hemlock (ICH) forests of southern British Columbia. We found significant relationships between ECM fungal diversity and both available and organic P; available P was also positively correlated with the abundance of two ECM taxa (Rhizopogon vinicolor group and Cenoccocum geophilum). By contrast, ECM fungal diversity varied unpredictably with total and mineralizable N or C to N ratio. We also found that soil C, N, available P, and forest floor depth did not exhibit strong patterns across stand ages. Overall, ECM fungal community structure was more strongly influenced by stand age than specific soil nutrients, but better correlations with soil nutrients may occur at broader spatial scales covering a wider range of site qualities.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号