Underground Forest Research Articles

Are degraded karst tiankengs coupled with microclimatic underground forests the refugia of surface flora? Evidence from China’s Yunnan

Karst tiankengs, as one of the most magnificent negative topographies, are capable of forming a bank for species diversity conservation easily. More than 300 karst tiankengs have been discovered and identified worldwide. Given its treacherous terrain, although original karst tiankeng were identified as species refuges, the broader distribution of degraded karst tiankeng has not been systematically studied. Our study area comprised the degraded karst tiankeng cluster immersed in the fragmented karst forests of Yunnan, China. Fifty-eight plant samples were selected from karst tiankengs and surface. We compared species composition, and analyzed diversity indices and similarity coefficients to verify the isolation effect of karst tiankengs on floras. The results indicated that: (1) In the degraded karst tiankeng, there were 24 families, 37 genera and 48 species in the tree layer and 27 families, 43 genera and 49 species in the shrub layer. Outside the degraded karst tiankengs, 20 families, 31 genera and 39 species were in the tree layer, and the shrub layer included 26 families, 44 genera and 55 species. (2) The species composition reached significant differences within and outside degraded karst tiankeng (p < 0.05) based on the analysis of variance (ANOVA). (3) In the degraded karst tiankeng, species richness/diversity in trees were higher than those in the shrub layer, while at the surface, shrubs had higher richness and lower diversity than trees by Alpha-diversity index. And for Beta-diversity index, species similarity among degraded karst tiankengs (0.215) was extremely dissimilar, which was even lower than the contrast within and outside the degraded karst tiankengs (0.272). (4) Shared species ranged from 1 to 5 among the four habitats, with high variability in plant species across the habitat matrices. Through a comparative analysis of systematic biodiversity methods, we found that the degraded karst tiankengs, an independent type of karst tiankeng, are the unreported refugia. Species records in degraded karst tiankeng cluster will contribute to plant diversity conservation and resource management, and to the linkage with broader China’s karst floras. Karst tiankeng botanical habitats possess not only biodiversity value for in situ conservation, but will further support the ecological recovery of surface flora. While its mechanism needs to be further revealed.

Is an Unmanned Aerial Vehicle (UAV) Suitable for Extracting the Stand Parameters of Inaccessible Underground Forests of Karst Tiankeng?

Unmanned aerial vehicle (UAV) remote sensing technology is gradually playing a role alternative to traditional field survey methods in monitoring plant functional traits of forest ecology. Few studies focused on monitoring functional trait ecology of underground forests of inaccessible negative terrain with UAV. The underground forests of tiankeng were discovered and are known as the inaccessible precious ecological refugia of extreme negative terrain. The aim of this research proposal is to explore the suitability of UAV technology for extracting the stand parameters of underground forests’ functional traits in karst tiankeng. Based on the multi-scale segmentation algorithm and object-oriented classification method, the canopy parameters (crown width and densities) of underground forests in degraded karst tiankeng were extracted by UAV remote sensing image data and appropriate features collection. First, a multi-scale segmentation algorithm was applied to attain the optimal segmentation scale to obtain the single wood canopy. Second, feature space optimization was used to construct the optimal feature space set for the image and then the k-nearest neighbor(k-NN) classifier was used to classify the image features. The features were classified into five types: canopy, grassland, road, gap, and bare land. Finally, both the crown densities and average crown width of the trees were calculated, and their accuracy were verified. The results showed that overall accuracy of object-oriented image feature classification was 85.60%, with 0.72 of kappa coefficient. The accuracy of tree canopy density extraction was 82.34%, for which kappa coefficient reached 0.91. The average canopy width of trees in the samples from the tiankeng-inside was 5.38 m, while that of the outside samples was 4.83 m. In conclusion, the canopy parameters in karst tiankeng were higher than those outside the tiankeng. Stand parameters extraction of karst tiankeng underground forests based on UAV remote sensing was relatively satisfactory. Thus, UAV technology provides a new approach to explore forest resources in inaccessible negative terrain such as karst tiankengs. In the future, we need to consider UAVs with more bands of cameras to extract more plant functional traits to promote the application of UAV for underground forest ecology research of more inaccessible negative terrain.

Metagenomic analysis reveals the different characteristics of microbial communities inside and outside the karst tiankeng

BackgroundKarst tiankengs serve as a reservoir of biodiversity in the degraded karst landscape areas. However, the microbial diversity of karst tiankengs is poorly understood. Here, we investigated the composition and function of the microbial community in a karst tiankeng.ResultsWe found that habitat differences inside and outside the karst tiankeng changed the composition and structure of the soil microbial communities, and the dominant phyla were Proteobacteria, Actinobacteria, Chloroflexi and Acidobacteria. The Shannon–Wiener diversity of microbial communities inside and outside the tiankeng was significantly different, and it was higher inside the tiankeng (IT). Venn and LEfSe analysis found that the soil microbial communities inside the tiankeng had 640 more endemic species and 39 more biomarker microbial clades than those identified outside of the tiankeng (OT)..Functional prediction indicated that soil microorganisms in outside the tiankeng had a high potential for carbohydrate metabolism, translation and amino acid metabolism. There were biomarker pathways associated with several of human diseases at both IT and OT sites. Except for auxiliary activities (AA), other CAZy classes had higher abundance at IT sites, which can readily convert litter and fix carbon and nitrogen, thereby supporting the development of underground forests. The differences in microbial communities were mainly related to the soil water content and soil total nitrogen.ConclusionsOur results provide a metagenomic overview of the karst tiankeng system and provide new insights into habitat conservation and biodiversity restoration in the area.

Characteristics of the Soil Microbial Communities in Different Slope Positions along an Inverted Stone Slope in a Degraded Karst Tiankeng.

Simple SummaryKarst tiankeng is a special and magnificent surface negative terrain with unique scientific value. The underground forests developed on inverted stone slopes in tiankeng are important areas for biodiversity conservation. This research used Illumina high-throughput sequencing technology to determine the soil microbial communities at four sites (at the bottom of the slope (BS), in the middle of the slope (MS), in the upper part of the slope (US), and outside the tiankeng (OT)) along the inverted stone slopes. The microbial communities at different slope positions presented similar compositions but different abundances. The dominant phyla in the inverted stone slope were Proteobacteria, Actinobacteria and Acidobacteria. The microbial community diversity was greater at the US site. The microbial communities with more abundant functional genes involved in C/N cycles were located at the BS site. The distribution of the microbial community was highly correlated with the Total nitrogen and pH. Understanding the soil microbial communities on inverted stone slopes is important for monitoring the ecology of tiankeng and biodiversity value assessments.The underground forests developed on inverted stone slopes in degraded karst tiankengs are important areas for biodiversity conservation, but the microbial community profiles have not been sufficiently characterized. Thus, we investigated the soil microbial communities at four sites (at the bottom of the slope (BS), in the middle of the slope (MS), in the upper part of the slope (US) and outside the tiankeng (OT)) in the Shenxiantang tiankeng. The dominant phyla in the inverted stone slope were Proteobacteria, Actinobacteria, and Acidobacteria, and the relative abundance were different in different slope positions. The Shannon–Wiener diversity index of the microbial community was significantly greater for the US site than for the MS or BS sites. The metabolism functional pathways (including C/N cycle) were more abundant at the BS site. Total nitrogen and pH were the dominant factors in determining the distribution of the microbial community along an inverted stone slope. These results suggest that topographic heterogeneity can influence the variations in the soil microbial structure, diversity, and function in degraded karst tiankengs and emphasized the ecological value of inverted stone slopes within karst tiankengs.

Suffrutex grasslands in south-central Angola: belowground biomass, root structure, soil characteristics and vegetation dynamics of the ‘underground forests of Africa’

AbstractDespite its importance for carbon stocks accounting, belowground biomass (BGB) has seldom been measured due to the methodological complexity involved. In this study, we assess woody BGB and related carbon stocks, soil properties and human impact on two common suffrutex grasslands (Brachystegia- and Parinari grasslands) on the Angolan Central Plateau. Data on BGB was measured by direct destructive sampling. Soil samples were analysed for select key parameters. To investigate vegetation dynamics and human impact, we used Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) and fire data retrieved via Google Earth Engine. Mean belowground woody biomass of sandy Parinari grasslands was 17 t/ha and 44 t/ha in ferralitic Brachystegia grasslands of which 50% correspond to carbon stocks. As such, the BGB of Brachystegia grasslands almost equals the amount of aboveground biomass (AGB) of neighbouring miombo woodlands. Almost the entire woody BGB is located in the top 30 cm of the soil. Soils were extremely acid, showing a low nutrient availability. Both grassland types differed strongly in EVI and fire seasonality. The Parinari grasslands burnt almost twice as frequent as Brachystegia grasslands in a 10-year period. Our study emphasizes the high relevance of BGB in suffrutex grasslands for carbon stock accounting.

Impact of Ex-Closure in above and below Ground Carbon Stock Biomass

Globally, there is a serious issue in carbon stock due to high deforestation and the loss of land, limited carbon storage pools in aboveground and underground forests in different regions, and increased carbon emissions to the atmosphere. This review paper highlights the impact of exclosures on above and below ground carbon stocks in biomass as a solution to globally curb carbon emissions. The data has been analyzed dependent on the Intergovernmental Panel on Climate Change (IPCC) guidelines, the Food and Agriculture Organization (FAO) Forest Resource Assessment report (FRA, 2020), and scientific journal publications mostly from the last decade, to show the research results of carbon stock and the impact of exclosures, particularly the challenges of deforestation and erosion of land and opportunities of area exclosures to provide a general outlook for policymakers. Overall, the world’s forest regions are declining, and although the forest loss rate has slowed, it has still not stopped sufficiently because the knowledge and practice of exclosures are limited. The global forest loss and carbon stock have decreased from 7.8 million ha/yr to 4.7 million ha/yr and from 668 gigatons to 662 gigatons respectively due to multiple factors that differ across the regions. However, a move toward natural rehabilitation and exclosures to reduce the emissions of Greenhouse Gas (GHGs) is needed. In the global production of carbon, the exclosure of forests plays an important role, in particular for permanent sinks of carbon.

Depth of Peat Burning and Carbon Loss during an Underground Forest Fire

Among forest fires, underground (peat) fires lead in terms of the amount of material burned per unit area and, consequently, the impact on climate change, but they differ in the complexity of assessing the loss of soil carbon and its emissions to the atmosphere. Using the example of the 2010 forest and peat fire in Moscow oblast (an area of 9 ha with a variable original tree-stand composition), the depth of burnout and loss of soil carbon were determined by reconstructing the prefire soil surface along the root collar of stumps, as well as comparing the characteristics of peat on the burned and adjacent areas. The average (median) burnout depth was 15 ± 8 (14) cm, varying in different areas from 13 ± 5 (11) to 20 ± 9 (19) cm. The burnout depth increased with the relative surface height and was maximum in areas with a predominance of aspen. Based on the data of the layer-by-layer determination of the bulk density, ash content, and carbon content in peat, the dependences of the carbon stock on the peat thickness are obtained. Based on them, and according the depth of burning, the carbon losses are estimated, which amount to an average (median) of 9.8 ± 5.57 (9.22) kg m–2 for the burned-out areas, varying in different areas from 8.61 ± 3.75 (7.39) to 12.9 ± 6.18 (12.3) kg m–2, which is equivalent to a one-time emission of almost 400 t СО2 ha—1 and at least 1.5 times higher than the possible release of CO2 into the atmosphere from the loss of carbon biomass of a growing stand with a stem wood stock of more than 280 m3 ha–1. The results correspond to the upper limit of estimates of soil carbon losses obtained by foreign authors and confirm the underestimation of the factor of underground (peat) fires in the boreal zone in comparison with the tropics and in general when considering the influence of forest and peatland ecosystems on the gas composition of the atmosphere and climate.

Rediscovery, range extension, habitat and phylogenetic relation of the endemic Scaled Sandveld Lizard Nucras scalaris Laurent, 1964 (Sauria: Lacertidae) in the central Angolan plateau

ABSTRACT The Scaled Sandveld Lizard Nucras scalaris Laurent, 1964 is a poorly known lacertid endemic to north-eastern Angola and is only known from the type series collected more than half a century ago. The original description provided a comprehensive morphological description, but there was a lack of information regarding its evolutionary relationships and habitat associations. A recent discovery of N. scalaris from Cusseque, Bié Province, on the central Angolan plateau provided the opportunity to address some knowledge gaps of this species. A phylogenetic analysis confirmed its distinctiveness at the species level. Despite a limited dataset, the analysis suggests that N. scalaris is sister to N. broadleyi rather than N. lalandii, the latter having been assumed to be the sister species, because of morphological similarity between them. The new record of N. scalaris represents a range extension of more than 350 km to the southwest and extends the elevation range to 1 570 m above sea level, compared to previous known localities at about 1 300 m above sea level (Alto Cuílo and Alto Chicapa, in Lunda Sul Province). The specimen also provides new information on live coloration, as well as the habitat association of grassy shrubland that is dominated by geoxylic suffrutices (the so-called ‘underground forests’) characteristic of the Angolan Miombo Woodlands. This new information raises the question whether poor survey data have led to an under-estimation of faunal diversity in this peculiar and overlooked vegetation type, and reinforces the need for further surveys which could highlight the importance of this habitat.

Soil microbial community characteristics in degraded karst tiankeng invaded by Eupatorium adenophorum.

After invading the grand negative landform karst degraded tiankeng, Eupatorium adenophorum will affect the plant diversity, community succession and natural ecological restoration of degraded tiankeng by changing soil microbial community. Taking the degraded tiankeng "Bajiaxiantang" as the research area, the soil around E. adenophorum roots in different habitats was selected to explore the microbial community characteristics of E. adenophorum roots using the Biolog-ECO micro-plate method. The results showed that the invasion degree of E. adenophorum was in order of pit slope shrub-grassland > pit bottom grassland > pit slope forest > pit head shrub-grassland. The characteristics of E. adenophorum varied among different habitats due to habitat heterogeneity. The change of microbial community metabolic activity, dominance index, richness index and evenness index of E. adenophorum roots was closely related with the invasion degree, with significant diffe-rence between inside and outside of the tiankeng. Amino acids and polymers were the main carbon sources utilized by soil microorganism. The α diversity of herbaceous plants in different habitats were correlated with that of soil microbial community. The diversity of soil microbial community around E. adenophorum roots increased significantly with the increases of invasion level, which could form a microenvironment conducive to invasion and colonization. In the future, the degraded tiankeng would eventually form the climax community of underground forests with community succession and natural ecological restoration, which might result in the disappearance of E. adenophorum in the degraded tiankeng.

西南喀斯特退化天坑负地形倒石坡的土壤微生物分布特征

PDF HTML阅读 XML下载 导出引用 引用提醒 西南喀斯特退化天坑负地形倒石坡的土壤微生物分布特征 DOI: 10.5846/stxb201808201766 作者: 作者单位: 福州大学生物科学与工程学院 福州,福州大学环境与资源学院;空间数据挖掘与信息共享教育部重点实验室,福州大学环境与资源学院 福州,厦门大学环境与生态学院 厦门;厦门大学环境与生态学院 厦门,福州大学环境与资源学院 福州 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41871198） Soil microorganism distribution characteristics of talus slope of negative topography in a degraded karst tiankeng in southwestern China Author: Affiliation: College of Biological Science and Engineering,Fuzhou University,College of Environment and Resources,Fuzhou University,College of Environment and Resources,Fuzhou University,College of the Environment and Ecology,Xiamen University,College of Environment and Resources,Fuzhou University Fund Project: Plant community assembly mechanism of karst tiankeng on the basis of functional traits in Yunnan,China 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:喀斯特退化天坑倒石坡作为一种负地形坡面，在退化天坑植物避难所的物种多样性保护中发挥着重要作用。研究坡面土壤微生物群落功能多样性，有助于阐明土壤微生物群落生态特征和空间分布规律，探索土壤微生物与植物多样性关联，挖掘退化天坑负地形倒石坡的生物多样性宝库价值。研究以云南沾益天坑群中的退化天坑-巴家陷塘为研究对象，运用Biolog微平板技术，分析坡面环境梯度（坑口﹑上坡位﹑中坡位﹑下坡位以及坑底）的土壤微生物群落功能多样性差异。结果显示，坑底土壤微生物群落的功能多样性指数（Shannon指数﹑Simpson指数﹑McIntosh指数）、碳源利用程度均显著高于坑口。下坡位的土壤微生物群落功能多样性略高于坑底，显著高于中坡位，呈现出下坡位 > 中坡位 > 上坡位的趋势。坡面土壤微生物群落主要利用的碳源为糖类和氨基酸类。2个主成分分别解释所有方差变量的31.9%和28.7%，能区分不同坡位土壤微生物群落的碳源利用。坑内外草本植物α多样性指数差异显著，坑坡木本层植物α多样性指数差异显著（P < 0.05），其中下坡位木本层植物多样性最高。β多样性指数显示不同坡位的生境具有差异性，但下坡位生境类型最多样。研究发现，喀斯特退化天坑倒石坡的独特负地形和土壤环境孕育了较高的植物多样性和土壤微生物群落功能多样性，二者的空间分布较为一致，未来在退化天坑物种多样性保护中应特别注意倒石坡地下森林资源价值。 Abstract:The negative topographic slopes in a degraded karst tiankeng play an important role in protecting plant diversity. Studying the functional diversity of soil microbial communities on slopes aids in clarifying the ecological characteristics and spatial distribution of soil, to explore the relationship between soil microorganisms and plant diversity, and to assess the biodiversity of degraded karst tiankengs. The degraded tiankeng "Bajiaxiantang" of Zhanyi county in Yunnan Province was selected as the study site. A Biolog MicroPlate was used to analyze the functional diversity of the soil microbial community in the slope environment and how soil microbial community functional diversity varied with gradient (pit, uphill, mid-slope, downhill, and pit bottom). The results showed that the functional diversity indices (Shannon, Simpson, and McIntosh) and the carbon source utilization degree of the soil microbial communities at the pit bottom were slightly higher than those at the pit level and were significantly higher than those at the mid-slope level, showing a trend of downhill > mid-slope > uphill. The main sources of carbon used by soil microbial community on slope are sugars and amino acids.. The two principal components account for 31.9% and 28.7% of all variance and can distinguish the carbon source utilization of soil microbial communities in different slope positions. The α diversity index of herbaceous plants inside and outside the pit was significantly different. The diversity index of woody plants on the slope was significantly different (P < 0.05), and the diversity index of the woody plants was highest downhill. The β diversity index showed that the habitats of the different slopes are different and that the habitats of the downhill area are the most diverse. The study found that the unique negative topography and soil environment of the degraded karst tiankeng talus slopes led to to higher plant diversity and higher functional diversity of soil microbial communities, and that the spatial distribution of the two is consistent. Thus, special attention should be paid to the value of underground forest resources on the talus slopes. 参考文献 相似文献 引证文献

Глубина прогорания торфа и потери углерода при лесном подземном пожаре

Глубина прогорания торфа и потери углерода при лесном подземном пожаре

Spatial pattern of plant community in original karst tiankeng: A case study of Zhanyi tiankeng in Yunnan, China

Damaosi is one of original karst tiankengs with underground virgin forest in Yunnan Pro-vince. The spatial point pattern analysis and the woody individual spatial structure parameters, including the uniform angle index, mingling degree and storey index, were used to estimate spatial pattern of the tiankeng's underground forest community. We also analyzed the intraspecific spatial distribution characteristics and interspecific spatial association on the basis of the individual relative position information of plant community. The results showed that the spatial distribution of plant community in Damaosi tiankeng was random. Plant species in the forest were moderately mixed. The vertical stratification of this forest was relatively simple, with stable structure and mature development characteristics of climax forest community. The populations in this community were mainly clustered in spatial distribution, negatively correlated between species and stronger negative correlation on the same vertical level. The larger the difference in the vertical level, the smaller the space competition was. The negative correlation in space became weaker with the increases of spatial scale. Tiankeng ecosystem was one type of precious natural habitats and plant refuges with high ecological stability. The stable structure of tiankeng plant community had important implications for the ecological resto-ration in karst areas.

Carbon sequestration potential of cropland reforestation on the northern slope of the Tianshan Mountains

The effect of land-use changes on soil carbon stocks has been an increasing concern in the context of global climate change. Through natural reforestation programs, abandoned cropland holds the potential of sequestering soil organic carbon (SOC) if the original forest could be recovered. In this study, we initially delineated the potential distribution of forest species on the north slope of the Tianshan Mountains using species distribution models. We then estimated the corresponding sequestration potential of SOC in the area delineated for reforestation. The deforestated area of a Picea schrenkiana forest converted to cropland (PSC) was defined by the potential and actual distributions of forest and cropland. The SOC contents of the forest and cropland soils were obtained through field sampling and laboratory analysis. We found that the area of the PSC was 26.77 × 105 ha, and the SOC loss (per unit area) derived from the conversion of forestland to cropland was 171.70 ± 28.20 Mg ha−1. The total SOC loss from the study area was 459.70 ± 75.49 Tg. This result implies that continuing the reforestation programs being implemented in the study area would increase SOC by the same amount. Additionally, we also estimated the total amount of carbon that would be sequestered in the aboveground and underground forest biomass on former cropland.

Estado da Arte na Quantificação de Biomassa em Raízes de Formações Florestais

RESUMO O objetivo do presente trabalho é apresentar uma visão geral sobre o estado da arte na obtenção de estimativas de biomassa e de carbono nas raízes de formações florestais. Inicialmente, realizou-se uma abordagem sobre a biomassa florestal, o ciclo do carbono na atmosfera e o papel das florestas nesse contexto. Sobre biomassa e carbono florestal, foram apresentadas definições, as metodologias citadas na literatura para a determinação e estimativa da biomassa florestal subterrânea, sendo realizado um apanhado geral dos métodos diretos e indiretos para sua quantificação. Na sequência, fez-se uma abordagem sobre as variáveis e os modelos utilizados nos ajustes de equações para estimativa de biomassa de raízes em formações florestais, como também foram relacionados alguns dos modelos mais utilizados e equações propostas na literatura.

Savanna fire and the origins of the 'underground forests' of Africa.

The origin of fire-adapted lineages is a long-standing question in ecology. Although phylogeny can provide a significant contribution to the ongoing debate, its use has been precluded by the lack of comprehensive DNA data. Here, we focus on the 'underground trees' (=geoxyles) of southern Africa, one of the most distinctive growth forms characteristic of fire-prone savannas. We placed geoxyles within the most comprehensive dated phylogeny for the regional flora comprising over 1400 woody species. Using this phylogeny, we tested whether African geoxyles evolved concomitantly with those of the South American cerrado and used their phylogenetic position to date the appearance of humid savannas. We found multiple independent origins of the geoxyle life-form mostly from the Pliocene, a period consistent with the origin of cerrado, with the majority of divergences occurring within the last 2million yr. When contrasted with their tree relatives, geoxyles occur in regions characterized by higher rainfall and greater fire frequency. Our results indicate that the geoxylic growth form may have evolved in response to the interactive effects of frequent fires and high precipitation. As such, geoxyles may be regarded as markers of fire-maintained savannas occurring in climates suitable for forests.

Investigating the origins of the “underground forests” of Africa

Investigating the origins of the “underground forests” of Africa

Subterranean Forest in India

THE accompanying notes and illustrations on the underground forest recently discovered in excavating the Prince's Dock, Bombay, were forwarded by Col. C. J. Merriman, R.E., C.S.I., Member of the Legislative Council, and Secretary to Government (Public Works Department), Bombay.