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1.
Adriana E. Olthoff Cristina G mez Josu G. Alday Carolina Martí nez-Ruiz 《Journal of Plant Ecology》2018,11(1):114
Aims Forest vegetation variability may be explained by the complex interplay among several spatial structuring factors, including climate and topography. We modelled the spatial variability of forest vegetation assemblages and significant environmental variables along a complex environmental gradient or coenocline to produce a detailed cartographic database portraying the distribution of forests along it.Methods We combined an analysis of ordination coenoclines with kriging over 772 field data plots from the third Spanish National Forest Inventory in an Atlantic–Mediterranean transitional area (northern Spain).Important findings The best fitted empirical semivariogram revealed a strong spatial structure of forest species composition along the complex environmental gradient considered (the climatic–topographic gradient from north to south). The steady and gradual increase of semivariance with a marked lag distance indicates a gradual turnover of forest assemblages according to the climatic–topographic variations (regional or local). Two changes in the slope of the semivariogram suggest the existence of two different scales of spatial variation. The interpolation map by Kriging of forest vegetation assemblages along the main coenocline shows a clear spatial distribution pattern of trees and shrubs in accordance with the spatial variation of significant environmental variables. We concluded that the multivariate geostatistical approach is a suitable technique for spatial analysis of forest systems employing data from national forest inventories based on a regular network of field plots. The development of an assortment of maps describing changes in vegetation assemblages and variation in environmental variables is expected to be a suitable tool for an integrated forest management and planning. 相似文献
2.
基于黑龙江省一类样地和生态公益林监测样地(共4163块)数据,应用局域Moran I及局域统计量(局域均值及局域标准差)检验4个尺度(25、50、100和150 km)下黑龙江省森林碳储量的空间分布模式、空间变异和空间相关性,并研究了2005和2010年森林碳储量的变化.结果表明: 黑龙江省森林碳储量空间分布存在显著空间正相关,森林碳储量均为相似的变化,而且都不是空间随机发生的;研究区森林碳储量受周围环境因子影响,空间分布存在异质性,且变异较大.2005—2010年,年均森林碳储量空间分布变化存在较大差异,呈增长趋势.局域统计量是描述森林碳储量随着空间和时间变化的有效方法,可以通过ArcGIS使结果可视化. 相似文献
3.
Vibrans AC Sevegnani L Uhlmann A Schorn LA Sobral MG de Gasper AL Lingner DV Brogni E Klemz G Godoy MB Verdi M 《Revista de biología tropical》2011,59(3):1371-1387
This study is part of the Floristic and Forest Inventory of Santa Catarina, conceived to evaluate forest resources, species composition and structure of forest remnants, providing information to update forest conservation and land use policy in Southern Brazilian State of Santa Catarina (95 000 km2). In accordance to the Brazilian National Forest Inventory (IFN-BR), the inventory applies systematic sampling, with 440 clusters containing four crosswise 1 000m2 plots (20 x 50m) each, located on a 10 x 10km grid overlaid to land use map based on classification of SPOT-4 images from 2005. Within the sample units, all woody individuals of the main stratum (DBH > or = 10cm) are measured and collected (fertile and sterile), if not undoubtedly identified in field. Regeneration stratum (height > 1.50m; DBH < 10cm) is registered in 100m2 in each sample unit. Floristic sampling includes collection of all fertile trees, shrubs and herbs within the sample unit and in its surroundings. This study performs analysis based on 92 clusters measured in 2008 within an area of 32320km2 of mixed ombrophyllous forests with Araucaria angustifolia located at the state's high plateau (500m to 1 560m above sea level at 26 degrees 00'-28 degrees 30' S and 49 degrees 13'-51 degrees 23' W). Mean density (DBH > or = 10cm) is 578 individuals/ha (ranging from 85/ha to 1 310/ha), mean species richness in measured remnants is 35 (8 to 62), Shannon and Wiener diversity index (H') varies between 1.05 and 3.48. Despite high total species diversity (364 Magnoliophyta, five Coniferophyta and one tree fern) and relatively high mean basal area (25.75m2/ha, varying from 3.87 to 68.85m2/ha), the overwhelming majority of forest fragments are considered highly impacted and impoverished, mostly by logging, burning and extensive cattle farming, turning necessary more efficient protection measures. Basal area was considered an appropriate indicator for stand quality and conservation status. 相似文献
4.
闽北异龄林生长矩阵模型研究 总被引:1,自引:0,他引:1
利用闽北地区1988年和1993年两次森林资源连续清查487块异龄林固定样地资料,运用主分量分析和回归正交设计方法分别选出异龄林地位主导因子和建立地位质量指数模型,在此基础上,建立了包含地位质量指数因子的异龄林生长矩阵模型. 相似文献
5.
6.
为探讨不同时间尺度、气候因子及林分因子对森林中树木死亡的影响,本研究以美国德克萨斯州东部的4个国家森林中264个重复调查的森林样地为对象,使用近20年来美国森林清查4个周期的数据,估算其在清查周期和年度水平上的树木死亡率变化,并使用广义线性混合效应模型来分析气候因子(干旱强度、干旱持续时间、年均温和年降水量)、树木大小(胸径)和林分因子(树木胸高断面积、林分密度和林分年龄)对树木存活的影响。结果表明: 在重度干旱当年和重度干旱的清查周期中,森林的树木死亡率分别增加了151%和123%,天气干扰(干旱和飓风)和植物之间的竞争是其主要的影响因素;干旱强度(标准化降水蒸散发指数,SPEI)和干旱持续时间对树木的存活具有显著的负效应,年降水量对树木的存活具有显著的正效应;树木胸高面积对树木存活具有显著的负效应,树木大小、林分年龄和林分密度对树木存活均具有显著的正效应,但是大树比小树更容易受到天气影响而死亡;在重度干旱的清查周期中,松树种组的树木死亡率(2.1%)比阔叶树木种组(3.9%)低,天然林的树木死亡率(3.0%)高于人工林(1.9%)。在分析树木死亡率时,需同时考虑个体树木大小、林分因子与气候因子的相对重要性。 相似文献
7.
Economic growth in Central Arizona, as in other semiarid systems characterized by low and variable rainfall, has historically depended on the effectiveness of strategies to manage water supply risks. Traditionally, the management of supply risks includes three elements: hard infrastructures, landscape management within the watershed, and a supporting set of institutions of which water markets are frequently the most important. In this paper we model the interactions between these elements. A forest restoration initiative in Central Arizona (the Four Forest Restoration Initiative, or 4FRI) will result in thinning of ponderosa pine forests in the upper watershed, with potential implications for both sedimentation rates and water delivery to reservoirs. Specifically, we model the net effect of ponderosa pine forest thinning across the Salt and Verde River watersheds on the reliability and cost of water supply to the Phoenix metropolitan area. We conclude that the sediment impacts of forest thinning (up to 50% of canopy cover) are unlikely to compromise the reliability of the reservoir system while thinning has the potential to increase annual water supply by 8%. This represents an estimated net present value of surface water storage of $104 million, considering both water consumption and hydropower generation. 相似文献
8.
Eucalypt forest structure and synthetic aperture radar backscatter: a theoretical analysis 总被引:1,自引:0,他引:1
Nicholas C. Coops 《Trees - Structure and Function》2002,16(1):28-46
Eucalypt forest attributes describing structure are required for a range of management and inventory programs. The characterization of vegetation structure can be a laborious task and so managers and researchers are seeking alternatives through the use of remote sensing. Forest structure and the distribution of biomass through the forest canopy has a significant effect on radar backscatter and, in many cases, is the overwhelming variable in determining the type and quantity of radar backscatter observed in forest environments. In southern Tasmania a combination of field-based inventory plots and forest type maps were accessed to condense large variations in forest structure into five archetypical structural forest types. We then utilized a forest backscatter model to simulate the backscatter response of these five forest structural types for a range of radar wavelengths and polarizations. Good correlative relationships were obtained between backscatter and forest structure. There was a particularly good relationship between synthetic aperture radar to variations in allocation of biomass to stems, branches, and leaves. These individual and grouped attributes in eucalypt forests appear to influence radar backscatter enough to develop predictive relationships between backscatter and forest structure. Strong correlations were observed with radar P- and C-band wavelengths with foliage and bole biomass and between the ratio of L to C with foliage and branch allocations. Within Australian wet sclerophyll forests, where the biomass is typically very high, the true capacity and applicability of radar imagery may not be in direct biomass estimation but rather in the capacity of radar data to stratify forest stands based on structural variation. 相似文献
9.
Courtney A. Schultz Thomas D. Sisk Barry R. Noon Martin A. Nie 《The Journal of wildlife management》2013,77(3):428-444
In 2012, the United States Forest Service (USFS) promulgated new planning regulations in accordance with the National Forest Management Act (NFMA). These regulations represent the most significant change in federal forest policy in decades and have sweeping implications for wildlife populations. We provide a brief overview of the history of the NFMA planning regulations and their wildlife provisions and review the current science on planning for effective wildlife conservation at the landscape scale. We then discuss the approach to wildlife conservation planning in the 2012 rule and compare it to alternatives that were not selected and previous iterations of the planning rule. The new planning rule is of concern because of its highly discretionary nature and the inconsistency between its intent on the one hand and operational requirements on the other. Therefore, we recommend that the USFS include in the Directives for implementing the rule commitments to directly monitor populations of selected species of conservation concern and focal species and to maintain the viability of both categories of species. Additional guidance must be included to ensure the effective selection of species of conservation concern and focal species, and these categories should overlap when possible. If the USFS determines that the planning unit is not inherently capable of maintaining viable populations of a species, this finding should be made available for scientific review and public comment, and in such cases the USFS should commit to doing nothing that would further impair the viability of such species. In cases where extrinsic factors decrease the viability of species, the USFS has an increased, not lessened, responsibility to protect those species. Monitoring plans must include trigger points that will initiate a review of management actions, and plans must include provisions to ensure monitoring takes place as planned. If wildlife provisions in forest plans are implemented so that they are enforceable and ensure consistency between intent and operational requirements, this will help to prevent the need for additional listings under the Endangered Species Act and facilitate delisting. Although the discretionary nature of the wildlife provisions in the planning rule gives cause for concern, forward-thinking USFS officials have the opportunity under the 2012 rule to create a robust and effective framework for wildlife conservation planning. © 2013 The Wildlife Society. 相似文献
10.
Andimuthu Ramachandran Parthasarathy Radhapriya Shanmuganathan Jayakumar Praveen Dhanya Rajadurai Geetha 《PloS one》2016,11(1)
India has one of the largest assemblages of tropical biodiversity, with its unique floristic composition of endemic species. However, current forest cover assessment is performed via satellite-based forest surveys, which have many limitations. The present study, which was performed in the Eastern Ghats, analysed the satellite-based inventory provided by forest surveys and inferred from the results that this process no longer provides adequate information for quantifying forest degradation in an empirical manner. The study analysed 21 soil properties and generated a forest soil quality index of the Eastern Ghats, using principal component analysis. Using matrix modules and geospatial technology, we compared the forest degradation status calculated from satellite-based forest surveys with the degradation status calculated from the forest soil quality index. The Forest Survey of India classified about 1.8% of the Eastern Ghats’ total area as degraded forests and the remainder (98.2%) as open, dense, and very dense forests, whereas the soil quality index results found that about 42.4% of the total area is degraded, with the remainder (57.6%) being non-degraded. Our ground truth verification analyses indicate that the forest soil quality index along with the forest cover density data from the Forest Survey of India are ideal tools for evaluating forest degradation. 相似文献
11.
Abstract. Natural dynamics in the boreal forest is influenced by disturbances. Fire recurrence affects community development and landscape diversity. Forest development was studied in the northeastern boreal forest of Quebec. The objective was to describe succession following fire and to assess the factors related to the changes in forest composition and structure. The study area is located in northeastern Quebec, 50 km north of Baie‐Comeau. We used the forest inventory data gathered by the Ministère des Ressources naturelles du Québec (MRNQ). In circular plots of 400 m2, the diameter at breast height (DBH) of all stems of tree species greater than 10 cm was recorded and in 40 m2 subplots, stems smaller than 10 cm were measured. A total of 380 plots were sampled in an area of 6000 km2. The fire history reconstruction was done based on historical maps, old aerial photographs and field sampling. A time‐since‐fire class, a deposit type, slope, slope aspect and altitude were attributed to each plot. Each plot was also described according to species richness and size structure characteristics. Traces of recent disturbance were also recorded in each plot. Changes in forest composition were described using ordination analyses (NMDS and CCA) and correlated with the explanatory variables. Two successional pathways were observed in the area and characterized by the early dominance of intolerant hardwood species or Picea mariana. With time elapsed since the last fire, composition converged towards either Picea mariana, Abies balsamea or a mixture of both species and the size structure of the coniferous dominated stands got more irregular. The environmental conditions varied between stands and explained part of the variability in composition. Their effect tended to decrease with increasing time elapsed since fire, as canopy composition was getting more similar. Gaps may be important to control forest dynamics in old successional communities. 相似文献
12.
白云山国家森林公园不同人为干扰强度的群落冠层结构和光照特征 总被引:1,自引:0,他引:1
为探究森林冠层结构与林下光照的变化规律及其相关性,在河南省白云山国家森林公园选取人工林、择伐林、皆伐林和老龄林建立四块面积为1 hm2(100 m×100 m)的固定监测样地,利用半球面影像技术获取冠层结构及林下光照数据。研究发现:1)随着人为干扰强度降低,冠层覆盖度与叶面积指数呈增加趋势,林下散射辐射与直接辐射呈减少趋势;2)择伐林冠层覆盖度与叶面积指数最大,平均叶倾角与透光比最小,林下光照(直接辐射、散射辐射)与冠层覆盖度和叶面积指数都呈显著负相关,林下散射辐射与冠层覆盖度和叶面积指数的负相关关系最强;3)处于不同干扰强度的群落由于冠层结构的差异,形成了不同群落内特定的光照环境。研究结果丰富了暖温带-亚热带生态过渡区森林冠层结构与林下光照动态变化研究资料,同时也为该区域森林的恢复与重建等提供科学的依据。 相似文献
13.
Land-use change in the Sarapiquí region of Costa Rica has resulted in a fragmented forest landscape with abrupt edges between forest and pasture. Forest responses to edge effects vary widely and can significantly affect ecosystem integrity. Our objective was to examine forest structure at 20+ yr old forest-pasture edges in Sarapiquí. Three transects with 0.095-ha plots at seven distances from forest edges were established in each of six forest patches. Stem density, basal area, and aboveground biomass in trees and palms ≥ 10-cm diameter at breast height were measured in all plots. In addition, hemispherical photographs were taken to determine leaf area index, understory light availability, and percent canopy openness. Linear mixed-effects models showed significantly higher tree stem density at forest edges, relative to interiors, a pattern reflected by increased stem density, basal area, and aboveground biomass in small diameter trees (≤ 20 cm) growing near edges. No differences in total tree basal area, aboveground biomass, or hemispherical photograph-derived parameters were detected across the forest edge to interior gradient. The recruitment of small diameter trees following edge creation has contributed to the development of dense vegetation at the forest edge and has aided in the maintenance of similar tree basal area and aboveground biomass between edge and interior environments. These data reflect on the robustness of forest edges in Sarapiquí, a characteristic that will likely minimize future detrimental edge effects and promote a number of high-value environmental services in these forests. 相似文献
14.
The production and quality of eucalyptus plantations have been studied in areas with different densities of ant nests, being important to estimate losses caused by leaf-cutting ants. The effects of leaf-cutting ant on wood production in differents productivity sites were studied in eucalyptus plantations in the region of Atlantic Forest, Minas Gerais State, Brazil from 2003 to 2006. Data of plots of the continuous forest inventory and data of leaf-cutting ant monitoring in eucalyptus plantations were obtained. Each unitary increment in the area of Atta spp. nests per hectare reduced the wood production of the eucalyptus forest between 0.04 and 0.13 m3.ha(-1), resulting in a level of economic damage for leaf-cutting ants between 13.4 and 39.2 m2.ha(-1), in this region. Moreover, this study innovated when using indices of forest productivity (site index) that promote better adjustment of the models and produce estimate more accurate of the level of economic damage for leaf-cutting ants in cultivated forests, allowing to conclude that the increase of the total area of ant nests reduces the wooden volume of eucalyptus, proportionally to the productive potential of the forest. 相似文献
15.
Jeanne Portier Florian Zellweger Jürgen Zell Iciar Alberdi Asensio Michal Bosela Johannes Breidenbach Vladimír ebe Rafael O. Wüest Brigitte Rohner 《Ecology and evolution》2022,12(6)
To understand the state and trends in biodiversity beyond the scope of monitoring programs, biodiversity indicators must be comparable across inventories. Species richness (SR) is one of the most widely used biodiversity indicators. However, as SR increases with the size of the area sampled, inventories using different plot sizes are hardly comparable. This study aims at producing a methodological framework that enables SR comparisons across plot‐based inventories with differing plot sizes. We used National Forest Inventory (NFI) data from Norway, Slovakia, Spain, and Switzerland to build sample‐based rarefaction curves by randomly incrementally aggregating plots, representing the relationship between SR and sampled area. As aggregated plots can be far apart and subject to different environmental conditions, we estimated the amount of environmental heterogeneity (EH) introduced in the aggregation process. By correcting for this EH, we produced adjusted rarefaction curves mimicking the sampling of environmentally homogeneous forest stands, thus reducing the effect of plot size and enabling reliable SR comparisons between inventories. Models were built using the Conway–Maxell–Poisson distribution to account for the underdispersed SR data. Our method successfully corrected for the EH introduced during the aggregation process in all countries, with better performances in Norway and Switzerland. We further found that SR comparisons across countries based on the country‐specific NFI plot sizes are misleading, and that our approach offers an opportunity to harmonize pan‐European SR monitoring. Our method provides reliable and comparable SR estimates for inventories that use different plot sizes. Our approach can be applied to any plot‐based inventory and count data other than SR, thus allowing a more comprehensive assessment of biodiversity across various scales and ecosystems. 相似文献
16.
Leandro Da Silva Duarte Rodrigo Scarton Bergamin Vinícius Marcilio-Silva Guilherme Dubal Dos Santos Seger Márcia Cristina Mendes Marques 《PloS one》2014,9(8)
Phylobetadiversity is defined as the phylogenetic resemblance between communities or biomes. Analyzing phylobetadiversity patterns among different vegetation physiognomies within a single biome is crucial to understand the historical affinities between them. Based on the widely accepted idea that different forest physiognomies within the Southern Brazilian Atlantic Forest constitute different facies of a single biome, we hypothesize that more recent phylogenetic nodes should drive phylobetadiversity gradients between the different forest types within the Atlantic Forest, as the phylogenetic divergence among those forest types is biogeographically recent. We compiled information from 206 checklists describing the occurrence of shrub/tree species across three different forest physiognomies within the Southern Brazilian Atlantic Forest (Dense, Mixed and Seasonal forests). We analyzed intra-site phylogenetic structure (phylogenetic diversity, net relatedness index and nearest taxon index) and phylobetadiversity between plots located at different forest types, using five different methods differing in sensitivity to either basal or terminal nodes (phylogenetic fuzzy weighting, COMDIST, COMDISTNT, UniFrac and Rao’s H). Mixed forests showed higher phylogenetic diversity and overdispersion than the other forest types. Furthermore, all forest types differed from each other in relation phylobetadiversity patterns, particularly when phylobetadiversity methods more sensitive to terminal nodes were employed. Mixed forests tended to show higher phylogenetic differentiation to Dense and Seasonal forests than these latter from each other. The higher phylogenetic diversity and phylobetadiversity levels found in Mixed forests when compared to the others likely result from the biogeographical origin of several taxa occurring in these forests. On one hand, Mixed forests shelter several temperate taxa, like the conifers Araucaria and Podocarpus. On the other hand, tropical groups, like Myrtaceae, are also very representative of this forest type. We point out to the need of more attention to Mixed forests as a conservation target within the Brazilian Atlantic Forest given their high phylogenetic uniqueness. 相似文献
17.
Forest ecosystems of an Arizona Pinus ponderosa landscape: multifactor classification and implications for ecological restoration 总被引:1,自引:0,他引:1
Aim We developed an ecosystem classification within a 110,000‐ha Arizona Pinus ponderosa P. & C. Lawson (ponderosa pine) landscape to support ecological restoration of these forests. Specific objectives included identifying key environmental variables constraining ecosystem distribution and comparing plant species composition, richness and tree growth among ecosystems. Location The Coconino National Forest and the Northern Arizona University Centennial Forest, in northern Arizona, USA. Methods We sampled geomorphology, soils and vegetation on 66 0.05‐ha plots in open stands containing trees of pre‐settlement (c. 1875) origin, and on 26 plots in dense post‐settlement stands. Using cluster analysis and ordination of vegetation and environment matrices, we classified plots into ecosystem types internally similar in environmental and vegetational characteristics. Results We identified 10 ecosystem types, ranging from dry, black cinders/Phacelia ecosystems to moist aspen/Lathyrus ecosystems. Texture, organic carbon and other soil properties reflecting the effects of parent materials structured ecosystem distribution across the landscape, and geomorphology was locally important. Plant species composition was ecosystem‐specific, with C3Festuca arizonica Vasey (Arizona fescue), for instance, abundant in mesic basalt/Festuca ecosystems. Mean P. ponderosa diameter increments ranged from 2.3–4.3 mm year?1 across ecosystems in stands of pre‐settlement origin, and the ecosystem classification was robust in dense post‐settlement stands. Main conclusions Several lines of evidence suggest that although species composition may have been altered since settlement, the same basic ecosystems occurred on this landscape in pre‐settlement forests, providing reference information for ecological restoration. Red cinders/Bahia ecosystems were rare historically and > 30% of their area has been burned by crown fires since 1950, indicating that priority could be given to restoring this ecosystem's remaining mapping units. Ecosystem classifications may be useful as data layers in gap analyses to identify restoration and conservation priorities. Ecosystem turnover occurs at broad extents on this landscape, and restoration must accordingly operate across large areas to encompass ecosystem diversity. By incorporating factors driving ecosystem composition, this ecosystem classification represents a framework for estimating spatial variation in ecological properties, such as species diversity, relevant to ecological restoration. 相似文献
18.
Large‐scale disturbance legacies and the climate sensitivity of primary Picea abies forests
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Jonathan S. Schurman Radek Bače Vojtěch Čada Shawn Fraver Pavel Janda Dominik Kulakowski Jana Labusova Martin Mikoláš Thomas A. Nagel Rupert Seidl Michal Synek Kristýna Svobodová Oleh Chaskovskyy Marius Teodosiu Miroslav Svoboda 《Global Change Biology》2018,24(5):2169-2181
Determining the drivers of shifting forest disturbance rates remains a pressing global change issue. Large‐scale forest dynamics are commonly assumed to be climate driven, but appropriately scaled disturbance histories are rarely available to assess how disturbance legacies alter subsequent disturbance rates and the climate sensitivity of disturbance. We compiled multiple tree ring‐based disturbance histories from primary Picea abies forest fragments distributed throughout five European landscapes spanning the Bohemian Forest and the Carpathian Mountains. The regional chronology includes 11,595 tree cores, with ring dates spanning the years 1750–2000, collected from 560 inventory plots in 37 stands distributed across a 1,000 km geographic gradient, amounting to the largest disturbance chronology yet constructed in Europe. Decadal disturbance rates varied significantly through time and declined after 1920, resulting in widespread increases in canopy tree age. Approximately 75% of current canopy area recruited prior to 1900. Long‐term disturbance patterns were compared to an historical drought reconstruction, and further linked to spatial variation in stand structure and contemporary disturbance patterns derived from LANDSAT imagery. Historically, decadal Palmer drought severity index minima corresponded to higher rates of canopy removal. The severity of contemporary disturbances increased with each stand's estimated time since last major disturbance, increased with mean diameter, and declined with increasing within‐stand structural variability. Reconstructed spatial patterns suggest that high small‐scale structural variability has historically acted to reduce large‐scale susceptibility and climate sensitivity of disturbance. Reduced disturbance rates since 1920, a potential legacy of high 19th century disturbance rates, have contributed to a recent region‐wide increase in disturbance susceptibility. Increasingly common high‐severity disturbances throughout primary Picea forests of Central Europe should be reinterpreted in light of both legacy effects (resulting in increased susceptibility) and climate change (resulting in increased exposure to extreme events). 相似文献
19.
溧阳地区森林景观的生物多样性评价 总被引:8,自引:0,他引:8
对在江苏省南部和太湖流域具有一定代表性的溧阳地区的森林景观开展了森林生态系统多样性的研究,对主要森林生态系统类型分层次进行了植物种多样性的调查分析,基于生态系统和物种两个水平的多样性调查, 以W和Z两个指标对研究区域森林景观的生物多样性特征进行历史的动态评价,结果体现出在近20a的森林经营过程中,溧阳地区森林景观的生物多样性水平有下降的趋势。/ 相似文献
20.
Should reference conditions be drawn from a single 10 ha plot? Assessing representativeness in a 10,000 ha old‐growth European beech forest
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JeriLynn E. Peck Brigitte Commarmot Martina L. Hobi Eric K. Zenner 《Restoration Ecology》2015,23(6):927-935
The management targets of modern forestry are often dictated by a desire to restore natural conditions, largely considered to be those found in contemporary reference sites. Beech reference sites are usually subjectively placed plots located in old‐growth reserves. Given the inherent variability in old‐growth, the validity of using a single such plot to guide restoration efforts is questionable. We therefore applied 3 methods to assess the representativeness of a 10 ha research plot in an old‐growth European beech (Fagus sylvatica L.) forest in Ukraine compared to an inventory of the entire 10,282 ha forest reserve. We compared the research plot to the 500‐m2 inventory plots using (1) permutation tests of structure metrics, (2) synthetic multivariate structural condition, and (3) functional condition via the proportion of area assigned to 8 forest development phases. Despite up to 82% distributional overlap for some metrics, both the averages and distributions of individual structural metrics (e.g. basal area, tree diameters) differed significantly between the RP and the inventory, as did the synthetic structural condition and the proportion of late optimal and decay phases. Extrapolations from this subjectively placed plot to the surrounding old‐growth matrix would overestimate several stereotypical “old‐growth” structures. These results support the need to draw on multiple reference sites and metrics and to select restoration target conditions that account for the variability associated with naturally dynamic ecosystems. A lack of absolute representativeness does not, however, necessarily preclude the generalizability of process‐based dynamics from old‐growth remnants. 相似文献