Diversity Of Herbaceous Layer Research Articles

北京地区油松人工林不同演替类型空间结构对林下植被及土壤的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 北京地区油松人工林不同演替类型空间结构对林下植被及土壤的影响 DOI: 10.5846/stxb202112143542 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 北京市园林绿化局项目"北京市国有林场精准提质"（20210618） Effects of spatial structure on understory vegetation and soil properties in Pinus tabuliformis plantation of different succession types in Beijing Author: Affiliation: 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:以北京地区油松（Pinus tabuliformis）人工林不同演替类型林分为研究对象，研究油松纯林、油松-栓皮栎（Quercus variabilis）混交林和栓皮栎纯林三种不同演替类型林分的空间结构、林下植被和土壤水分的变化规律及其相互作用关系。结果表明：（1）林分水平及垂直空间结构、草本层物种多样性、更新幼树生长、土壤持水和透气性能等指标在三种不同演替类型林分间差异显著（P<0.05），林分空间结构参数中的角尺度、林层指数和开敞度显著影响了各类型林分的灌草多样性，混交度、林层指数和大小比数显著影响了更新幼树的生长，混交度和林层指数显著影响了土壤水分的变化（P<0.05）。（2）松栎混交林灌草生物量、天然更新幼树的生长以及土壤水分物理状况均好于纯林，并主要受林分混交度和林层指数的共同作用。（3）各演替类型林分内均存在栓皮栎更新幼树，混交林栓皮栎更新幼树数量最多、长势最好，对林地资源的竞争最为激烈。因此，可以通过调整林分空间结构实现种间关系及林地资源的调控，以充分发挥森林生态系统的各项功能与价值。 Abstract:Using different succession types of Pinus tabuliformis plantation in the Beijing area as the research object, this study investigated the change rules and interaction of stand spatial structure, understory vegetation, and soil water of three different succession types:Pinus tabuliformis pure forests, Pine-Quercus mixed forests, and Quercus variabilis pure forests. The results were as follows. (1) There were significant differences in horizontal and vertical stand spatial structure, species diversity of herbaceous layer, saplings growth, and soil water physical properties among the three different succession types (P<0.05). In addition, the angle index, stand layer index and opening degree index of stand spatial structure parameters significantly affected the shrub and grass diversity of each type of stand (P<0.05), while the mingling degree, stand layer index and neighborhood comparison significantly affected the growth of saplings (P<0.05), and the mingling degree and stand layer index significantly affected the change of soil water (P<0.05). (2) The biomass of shrub and grass, saplings growth, and the physical condition of soil water were all the better within the mixed forest than in the pure forest and were mostly influenced by the mingling degree and the stand layer index. (3) The natural regeneration saplings of Quercus variabilis were observed in all succession types, with mixed forest having the most saplings and the best growth and the most intensive competition for forest resources. Therefore, interspecific relationships and forest resources can be regulated by adjusting the spatial structure of stand, so as to give full play to the functions and values of forest ecosystem. 参考文献 相似文献 引证文献

Thinning can increase shrub diversity and decrease herb diversity by regulating light and soil environments.

Tree thinning affects the light environment, which in turn affects the growth and survival of understory vegetation, thus improving species diversity and nutrient cycling, as well as the ecological habitat factors. However, the response of understory vegetation to the thinning intensity and short-time effects in the temperate broadleaf-conifer mixed forest is not completely clear. In this study, four permanent plots with a total area of 4 hm2 were established in a mixed broadleaf-conifer forest in northeast China, with thinning intensities of 20% (light thinning, LT), 35% (medium thinning, MT), 55% (heavy thinning, HT) and the unthinned plot (CK), respectively, in accordance with the basal area. The responses of species diversity to changes in understory vegetation were conducted by a structural equation model (SEM). The results showed that compared with CK, thinning significantly increased the photosynthetically active radiation (PAR) and the light quality (R/FR) (p < 0.05), while decreased the contents of soil total nitrogen (TN), total phosphorous (TP), organic matter (OM), nitrate nitrogen (NN), ammonia nitrogen (AN) and pH. The degree of fragmentation of light factors among the treatment plots gradually decreased as thinning intensity increased. Among all the thinning treatments, PAR and R/FR were found to be the optimal light condition when the forest thinning intensity was 55%. The light condition was found to have a significant negative correlation with soil TN, TP, OM, and AN. While the soil nutrients were positively correlated with herbaceous layer diversity but negatively correlated with shrub layer diversity. The soil nutrients were lost after thinning in a short time and herb diversity decreased, but shrub diversity increased significantly compared with unthinned plots. For the understory vegetation, the species diversity of shrub and herb layer were showed to be more sensitive to soil nutrients than light environment.

Excess Nitrogen in Temperate Forest Ecosystems Decreases Herbaceous Layer Diversity and Shifts Control from Soil to Canopy Structure

Research Highlights: Excess N from atmospheric deposition has been shown to decrease plant biodiversity of impacted forests, especially in its effects on herbaceous layer communities. This work demonstrates that one of the mechanisms of such response is in N-mediated changes in the response of herb communities to soil resources and light availability. Background and Objectives: Numerous studies in a variety of forest types have shown that excess N can cause loss of biodiversity of herb layer communities, which are typically responsive to spatial patterns of soil resource and light availability. The objectives of this study were to examine (1) gradients of temporal change in herb composition over a quarter century, and (2) spatial patterns of herb cover and diversity and how they are influenced by soil resources and canopy structure. Materials and Methods: This study used two watersheds (WS) at the Fernow Experimental Forest, West Virginia, USA: WS4 as an untreated reference and WS3 as treatment, receiving 35 kg N/ha/yr via aerial application. Herb cover and composition was measured in seven permanent plots/WS from 1991 to 2014. In 2011, soil moisture and several metrics of soil N availability were measured in each plot, along with measurement of several canopy structural variables. Backwards stepwise regression was used to determine relationships between herb cover/diversity and soil/canopy measurements. Results: Herb diversity and composition varied only slightly over time on reference WS4, in contrast to substantial change on N-treated WS3. Herb layer diversity appeared to respond to neither soil nor canopy variables on either watershed. Herb cover varied spatially with soil resources on WS4, whereas cover varied spatially with canopy structure on WS3. Conclusions: Results support work in many forest types that excess N can decrease plant diversity in impacted stands. Much of this response is likely related to N-mediated changes in the response of the herb layer to soil N and light availability.

Ungulate browsers promote herbaceous layer diversity in logged temperate forests.

Ungulates are leading drivers of plant communities worldwide, with impacts linked to animal density, disturbance and vegetation structure, and site productivity. Many ecosystems have more than one ungulate species; however, few studies have specifically examined the combined effects of two or more species on plant communities. We examined the extent to which two ungulate browsers (moose [Alces americanus]) and white‐tailed deer [Odocoileus virginianus]) have additive (compounding) or compensatory (opposing) effects on herbaceous layer composition and diversity, 5–6 years after timber harvest in Massachusetts, USA. We established three combinations of ungulates using two types of fenced exclosures – none (full exclosure), deer (partial exclosure), and deer + moose (control) in six replicated blocks. Species composition diverged among browser treatments, and changes were generally additive. Plant assemblages characteristic of closed canopy forests were less abundant and assemblages characteristic of open/disturbed habitats were more abundant in deer + moose plots compared with ungulate excluded areas. Browsing by deer + moose resulted in greater herbaceous species richness at the plot scale (169 m2) and greater woody species richness at the subplot scale (1 m2) than ungulate exclusion and deer alone. Browsing by deer + moose resulted in strong changes to the composition, structure, and diversity of forest herbaceous layers, relative to areas free of ungulates and areas browed by white‐tailed deer alone. Our results provide evidence that moderate browsing in forest openings can promote both herbaceous and woody plant diversity. These results are consistent with the classic grazing‐species richness curve, but have rarely been documented in forests.

Long-Term Deer Exclusion Has Complex Effects On A Suburban Forest Understory

Abstract Herbivory by deer is one of the leading biotic disturbances on forest understories (i.e., herbs, small shrubs, and small tree seedlings). A large body of research has reported declines in height, abundance, and reproductive capacity of forbs and woody plants coupled with increases in abundance of graminoids, ferns, and exotic species due to deer herbivory. Less clear is the extent to which (and the direction in which) deer alter herbaceous layer diversity, where much of the plant diversity in a forest occurs. We examined the effect of 15 y of deer exclusion on the understory of a suburban hardwood forest in Connecticut exposed to decades of intensive herbivory by white-tailed deer (Odocoileus virginianus). We compared species richness (at subplot and plot scale), individual species and life form group abundance (% cover), and community composition between grazed and exclosure plots, as well as between mesic and wet soil blocks. Forb cover was more than twice as abundant in exclosure as in grazed ...

Phytosociological Analysis and Species Diversity of Herbaceous Layer in Rashad and Alabassia Localities , South Kordofan State , Sudan

Phytosociological Analysis and Species Diversity of Herbaceous Layer in Rashad and Alabassia Localities , South Kordofan State , Sudan

Isolated cork oak trees affect soil properties and biodiversity in a Mediterranean wooded grassland

Mediterranean wooded grasslands are multipurpose systems that support high plant and animal diversity levels and are habitats of European importance (i.e., 6310 – Dehesas with evergreen Quercus spp.). Moreover, these systems offer a number of agro-ecosystem services such as forage production, soil carbon sequestration, nutrient recycling and soil protection. The scattered trees enhance the ecological complexity of grassland influencing the soil properties, the herbaceous layer diversity and composition and the soil communities. Understanding how isolated trees influence the other components of the system is essential to comprehend their role supporting high levels of above and below ground biodiversity and ecosystem services.In the present study, we present a hypothetical framework of the effects of isolated trees on soil properties, plant and soil fauna assemblages, the latter here represented by the class Collembola. The floor litter and the associated input of organic matter to the soil was a key factor linking the components of the tree-soil-biodiversity system in a Mediterranean cork oak wooded grassland.Topsoil C increased by +50% under the tree canopy in comparison with the areas beyond the tree canopy. Plant diversity was lower under tree canopy, but contributed to enhance the total species richness of the grassland. Collembolan diversity was higher under the peculiar conditions beneath the tree canopy. Relationships between plant and collembolan species emerged.The findings of this study suggest that isolated trees have direct and indirect effects on soil properties, plant and collembolan assemblages, hence they can influence the ecological processes of wooded grasslands, with implications for food webs, nutrient cycling and productivity of the agro-ecosystem.

English

In order to study the structure of herbaceous biodiversity and its effect factors in broad-leaved Korean pine forest, a total of 100 1-m2 sub-plots were established in the 1 ha site which was monthly investigated from May to September in 2009. Data on soil attributes were also investigated (soil organic matter, available nitrogen, available phosphorus, available potassium, soil, water and pH) without light environment (leaf area index (LAI), photosynthetic photon flux density (PPFD) and, canopy presence). In this paper, the relationships between different layers (tree, shrub and herbaceous), soil attributes and light environment were analyzed. The effects of tree and shrub layers, soil attributes and light environment on the structure of herbaceous diversity were also discussed. The results show that there is an obvious seasonal dynamic for the herb in broad-leaved Korean pine forest. It was dominated by Anemone amurensis (Korsh.) Kom. and Corydalis ambigua Cham. et Schltdl. in May. The highest species richness was in June, when spring ephemeral, early and late-summer plant grew at the same time.&nbsp;July was the growing season and had highest diversity. From August to September, summer plant became withered gradually. There is a significant positive correlation between the diversity in shrub and herb layer Density of shrub layer positively correlated with the cover of herb layer, but negatively correlated with the diversity of herbaceous layer. The effect of the tree layer on the cover and the diversity of herbaceous layer did not arrive at the significant level. The correlation analysis of the cover, diversity and soil attributes, light environment at herbaceous layer, as well as the tree and shrub layer, indicated that available potassium, PPFD, soil water was the key connection between the tree- and shrub layer. The site locates in the broad-leaved Korean pine forest belonged to the old forest which could explain why the tree layer was not related to herbaceous layer in this paper.&nbsp;&nbsp;Therefore, it could be concluded that, the influence of the tree layer on the structure of herbaceous biodiversity carried out through the direct effect on light environment, precipitation and litter. &nbsp; Key words: Tree layer, shrub layer, herbaceous layer, seasonal dynamic, soil attributes, light environment.

Phytosociological analysis of Herbaceous layer in the Temperate Forests of Gurez Valley of Jammu &amp; Kashmir

The present study was conducted with a view to access the present status of diversity of herbaceous layer of Gurez valley. The study area is highly rich in non-timber forest products like Saussurea costus, Artemisia spp., Podophyllum hexandrum, Aconitum heterophyllum, Jurinea macrocephala and many other such plants which are very important for their high medicinal value. An attempt has been made to study the phytosociological status of the herbaceous layer of the Gurez valley.

Positive relationship between herbaceous layer diversity and the performance of soil biota in a temperate forest

Abstract The current decline in biodiversity is particularly pronounced in the herbaceous layer of forest ecosystems. We explored the relationship between a naturally occurring plant diversity gradient in the understory vegetation of a deciduous forest and several above-and belowground ecosystem processes. We show that particularly soil microbial parameters and microarthropod densities are positively correlated with plant species richness. These results confirm recent findings in grassland ecosystems and highlight the intimate interconnectance between the diversity and functioning of above-and belowground compartments. We conclude that irrespective of a potential causal relationship between plant species richness and belowground processes, it is essential to consider the performance of soil biota in order to understand the relationship between herbaceous layer composition and ecosystem function.

Scale-dependent effects of pines on the herbaceous layer diversity in a semi-arid mediterranean ecosystem

In arid and semi-arid ecosystems, the presence of woody neighbours affects the existence of several herbaceous species by modifying critical aspects of the environment (e.g., soil humidity, nutrient content or light availability) beneath their canopies. Herbaceous species growing in the understory of Pinus pinaster may be distinct from those in open areas due to litter fall, light interception and changes in nutrient availability. We suggest that the overall effect of woody neighbours on herbaceous layer diversity may vary with the scale focus of analysis. To examine this hypothesis, we collected data on the abundance of herbaceous species in open pineland forests of the central Iberian Peninsula (Spain) using sample quadrats of 0.5 m × 0.5 m distributed beneath, at the edge, and outside the canopy of pines in a landscape composed of dunes and plains. The results of CCA ordination revealed significant spatial segregation of herbaceous species reflecting the occurrence of pines and dunes in the landscape. ...

Vegetation characteristics of forested hillside seeps in eastern Maine, USA1,2

Abstract The influence of forested hillside seeps on local biodiversity is not well known in the glaciated northeastern USA. We documented the physical and vegetative characteristics of fifteen forested seeps and adjacent uplands to determine their contribution to local biodiversity and to improve existing regional seep classification methods. We determined the uniqueness of plant species using the Indicator Value Method, a method that combines individual species' relative abundance with its relative frequency of occurrence to produce a score (0–100%) based on the ability of that species to be associated within a defined group. We used nonmetric multidimensional scaling (NMDS) to address species-site relationships. Hardwood seeps were always located on slopes from 8–12° and were between 5 and 800 m2 in area. Conifer seeps were also located on similar slopes, but were typically larger (900 to 3600 m2) and within areas of lower topography or ‘benches’ on a hillslope. Herbaceous layer diversity (H′) was high...

Effects of harvesting on herbaceous layer diversity of a central Appalachian hardwood forest in West Virginia, USA

Clearcutting is a common harvesting practice in many eastern hardwood forests. Among the vegetation strata of these forests, the herbaceous layer is potentially the most sensitive in its response to harvest-mediated disturbances and has the highest species diversity. Thus, it is important to understand the response of herbaceous layer diversity to forest harvesting. Previous work on clearcut and mature stands at the Fernow Experimental Forest (FEF), West Virginia, has shown that, although, harvesting did not alter appreciably herbaceous layer cover, it influenced the relationship of cover to biotic and abiotic factors, such as tree density and soil nutrients, respectively. The purpose of this study was to examine the response of species diversity of the herbaceous layer to harvesting at FEF. Fifteen circular, 0.04 ha sample plots were established in each of four watersheds (60 plots in total) representing two stand age categories: two watersheds with 20 years even-age stands following clearcutting and two watersheds with mature second growth stands. All woody stems ≥2.5 cm diameter at breast height were identified, tallied, and measured for diameter. The herbaceous layer was sampled by identifying all vascular plants ≤1 m in height and estimating cover for each species in each of 10 (1 m 2) circular sub-plots per sample plot (600 sub-plots total). Species diversity for each plot was calculated from herbaceous layer data using the ln-based Shannon Index ( H′) equation. Ten stand and soil variables also were measured on each plot. Mean herbaceous layer cover for clearcut versus mature stands was 27.2±14.3% versus 20.2±8.1% ( P>0.05), respectively and mean H′ was 1.67±0.42 versus 1.55±0.48 ( P>0.05), respectively. Herbaceous layer diversity was negatively correlated with cation exchange capacity and extractable Ca and Mg in the mineral soil in clearcut stands. In contrast, herbaceous layer diversity was positively correlated with soil organic matter and clay content. Although, 20 years of recovery after clearcutting did not have significant effects on the species diversity of the herbaceous layer when examining stand age means alone, harvesting did appear to influence the spatial relationships between herbaceous layer diversity and biotic factors (e.g. tree density) and abiotic factors (e.g. soil nutrients).