Natural Broad-leaved Forest Research Articles

Non-Timber Forest Products: an alternative source of rural income

Dandapakhar, in Sindhu Palchok District of Nepal, was the focus area for the Nepal Australia Community Resource Management Project to undertake action research on the potential of NTFPs as a source of rural income. The area is located along the Jiri Road at an altitude between 2000 and 3000 meters, and is rich in natural broad-leaved forest harboring a large variety of indigenously occurring species having medicinal, aromatic and other values. The species occurring in Dandapakhar have both traditional and non-traditional uses and (the potential to) command, in some cases, significant market prices, not only locally, but also in Kathmandu andthe international market.

Beneficial effects of native broadleaved forests on canopy beetle diversity are not reduced by admixture of non‐native conifers

Abstract Biodiversity loss and vast forest diebacks due to climate change‐induced disturbances require adapted forest management strategies that reconcile economic interests and conservation. Tree species selection, including admixture of fast‐growing and drought‐tolerant non‐native species to native forests, is an increasingly considered approach. However, we lack data on how such mixtures affect native forest biodiversity, especially for the sparsely researched major above‐ground part of trees, the canopy. In 40 temperate forest plots in northwest Germany, we investigated how monocultures and admixtures of introduced fast‐growing conifers (native Norway spruce planted outside its natural range and non‐native Douglas fir) to native broadleaved European beech forests affect abundance, biomass, taxonomic and functional diversity and community composition of canopy beetles across trophic guilds. Diverse arthropod communities are vital contributors to forest health and resilience, and therefore valuable indicators to assess and evaluate forestry measures. Monospecific stands of non‐native Douglas fir reduced canopy beetle abundance and diversity compared to native European beech, exceeding the negative effects of Norway spruce. These effects were more pronounced for herbivorous beetles, while they were less strong for predators. Beetle communities in monospecific Norway spruce stands had low functional richness. European beech and mixtures with non‐native Douglas fir had high dissimilarity between local communities (turnover, i.e. beta diversity) and high total beetle diversity at landscape scale (gamma diversity). Mixtures generally mitigated the negative effects of introduced conifers, including shifts in species community composition compared to native European beech. Synthesis and applications: Monospecific stands of fast‐growing non‐native Douglas fir and native Norway spruce planted outside its natural occurrence showed undesirable effects such as low diversity and a shifted community composition of canopy beetles compared to native European beech. However, mixed stands mitigated negative effects and specifically admixed non‐native Douglas fir did not reduce species turnover and landscape‐scale beetle diversity. In line with recent studies on other forest taxa, we conclude that admixtures of introduced conifers to European beech forests, but not monospecific plantations, can potentially serve as a compromise between conservational and economic interests.

Effects of topography and stand spatial structure on the diameter at breast height growth of major pioneer tree species of natural broad-leaved mixed forests in Zhejiang Province, China.

Based on the continuous inventory data of forest resources in Zhejiang Province in 2019 and 2021, we used statistical methods such as polynomial regression to analyze the impacts of topography and forest spatial structure on average annual diameter at breast height (DBH) growth of main pioneer tree species in natural broad-leaved mixed forests. The results showed that DBH of Schima superba, Quercus glauca, Quercus fabri, Lithocarpus glaber, Castanopsis eyrei, and Castanopsis sclerophylla were between 5-50.8, 5-41.5, 5-50.8, 5-43.9, 5-55.5, and 5-46.1 cm, respectively. We classified all the trees into three classes based on DBH: small (6-12 cm), medium (12-14 cm), and large (>26 cm). The average annual DBH growth of S. superba and Q. glauca was the highest on semi-shady slope and shady slope, with increases of 2.9%-15.7% and 1.1%-41.2%, respectively. The average annual DBH growth of large-diameter S. superba, L. glaber, C. eyrei and C. sclerophylla decreased with the increase of slope, with a maximum decrease of 27.0% for S. superba, with no significant difference among small- and medium-diameter trees as a whole. The slope position did not affect the annual DBH growth of small-diameter trees, while that of medium- and large-diameter S. superba, Q. glauca, and large-diameter Q. fabri, L. glaber decreased with the change of slope position from downhill, mesoslope, uphill to ridge, with a maximum decrease of 28.1% for L. glabe, and the major-diameter C. eyrei was on the contrary. Appropriate increase in the mingling was beneficial to the average annual DBH growth of medium- and large-diameter trees. Moderate mixing was suitable for S. superba, while low degree mixing and moderate mixing was suitable for Q. glauca, Q. fabri and L. glaber, and intensive mixing was suitable for C. eyrei and C. sclerophylla. No significant difference was observed for minor-diameter trees under the mingling. The neighborhood comparison only had a significant effect on the average annual DBH growth of large-diameter Q. glauca, Q. fabri, and L. glaber, which was significantly higher under subdominance-moderation than moderation-inferiority. The average annual DBH growth in the study area was mainly affected by aspect and mixing degree.

Spatial predictions and uncertainties of forest carbon fluxes for carbon accounting

Countries have pledged to different national and international environmental agreements, most prominently the climate change mitigation targets of the Paris Agreement. Accounting for carbon stocks and flows (fluxes) is essential for countries that have recently adopted the United Nations System of Environmental-Economic Accounting - ecosystem accounting framework (UNSEEA) as a global statistical standard. In this paper, we analyze how spatial carbon fluxes can be used in support of the UNSEEA carbon accounts in five case countries with available in-situ data. Using global multi-date biomass map products and other remotely sensed data, we mapped the 2010–2018 carbon fluxes in Brazil, the Netherlands, the Philippines, Sweden and the USA using National Forest Inventory (NFI) and local biomass maps from airborne LiDAR as reference data. We identified areas that are unsupported by the reference data within environmental feature space (6–47% of vegetated country area); cross-validated an ensemble machine learning (RMSE=9–39 Mg C textrm{ha}^{-1} and textrm{R}^{2}=0.16–0.71) used to map carbon fluxes with prediction intervals; and assessed spatially correlated residuals (<5 km) before aggregating carbon fluxes from 1-ha pixels to UNSEEA forest classes. The resulting carbon accounting tables revealed the net carbon sequestration in natural broadleaved forests. Both in plantations and in other woody vegetation ecosystems, emissions exceeded sequestration. Overall, our estimates align with FAO-Forest Resource Assessment and national studies with the largest deviations in Brazil and USA. These two countries used highly clustered reference data, where clustering caused uncertainty given the need to extrapolate to under-sampled areas. We finally provide recommendations to mitigate the effect of under-sampling and to better account for the uncertainties once carbon stocks and flows need to be aggregated in relatively smaller countries. These actions are timely given the global initiatives that aim to upscale UNSEEA carbon accounting.

Long-term successive rotation affects soil microbial resource limitation and carbon use efficiency in Chinese fir (Cunninghamia lanceolata) monoculture plantations

Long-term successive rotation has resulted in negative effects on stand productivity, soil nutrient pool and microbial diversity and function in monoculture tree plantations. However, how successive rotation influences soil microbial nutrient limitation and carbon use efficiency (CUE) and their linkage with resource carbon (C): nitrogen (N): phosphorus (P) stoichiometry remain largely unknown. To solve this puzzle, we compared the C:N:P stoichiometries of leaf litter, fine root and soil, as well as microbial biomass and enzyme activities among three Chinese fir (Cunninghamia lanceolata) plantations with first (FRP), second (SRP) and third (TRP) generations and a natural broad-leaved forest (BL). We found that long-term successive rotation of Chinese fir decreased litter biomass by 64.7% ∼ 80.9% and enhanced litter C:N ratio by 2.7% ∼ 36.0% compared to the BL. Successive rotation decreased the contents of dissolved organic C, total N, and soil C:P and N:P ratios, and resulted in an increased C:N imbalance between soil microorganisms and nutrients in the TRP generation. Long-term successive rotation increased microbial C limitation by 1.5% ∼ 11.1% but decreased N and P limitations by 127.3% ∼ 160.9% and 15.3% ∼ 37.5%, compared with the BL, and resulted in significant increases in microbial CUE and substrate-induced respiration rate of C to N sources in the TRP generation. Structural equation modeling suggested that successive rotation indirectly affected microbial CUE and SIR by changing litter C:N, enzyme C:N and soil C:N imbalance. Collectively, these findings indicated that long-term successive rotation aggravated soil microbial C (energy) limitation and affected microbial CUE and capacity due to the increased stoichiometric imbalance between their resources. Future management practices that could increase litter and soil quality could be helpful to decrease microbial C limitation and maintain microbial functionality for sustainable monoculture plantations.

Application of a Novel Multiscale Global Graph Convolutional Neural Network to Improve the Accuracy of Forest Type Classification Using Aerial Photographs

The accurate classification of forest types is critical for sustainable forest management. In this study, a novel multiscale global graph convolutional neural network (MSG-GCN) was compared with random forest (RF), U-Net, and U-Net++ models in terms of the classification of natural mixed forest (NMX), natural broadleaved forest (NBL), and conifer plantation (CP) using very high-resolution aerial photographs from the University of Tokyo Chiba Forest in central Japan. Our MSG-GCN architecture is novel in the following respects: The convolutional kernel scale of the encoder is unlike those of other models; local attention replaces the conventional U-Net++ skip connection; a multiscale graph convolutional neural block is embedded into the end layer of the encoder module; and various decoding layers are spliced to preserve high- and low-level feature information and to improve the decision capacity for boundary cells. The MSG-GCN achieved higher classification accuracy than other state-of-the-art (SOTA) methods. The classification accuracy in terms of NMX was lower compared with NBL and CP. The RF method produced severe salt-and-pepper noise. The U-Net and U-Net++ methods frequently produced error patches and the edges between different forest types were rough and blurred. In contrast, the MSG-GCN method had fewer misclassification patches and showed clear edges between different forest types. Most areas misclassified by MSG-GCN were on edges, while misclassification patches were randomly distributed in internal areas for U-Net and U-Net++. We made full use of artificial intelligence and very high-resolution remote sensing data to create accurate maps to aid forest management and facilitate efficient and accurate forest resource inventory taking in Japan.

Unraveling the Importance of Forest Structure and Composition Driving Soil Microbial and Enzymatic Responses in the Subtropical Forest Soils

As the responsive soil properties, soil microbial fractions and enzymatic activities are often recommended for assessing soil environment. Different flora, silvicultural practices, and anthropogenic activities regulate essential ecosystem processes. They could substantially affect biological properties, nutrient budgets, and biogeochemical cycles at local and regional scales. This study examined how different forest compositions influenced by various anthropogenic activities (land use change, over-exploitation, species translocation) affect soil microbial properties and enzymatic activities, as well as the effects of soil chemical properties on these patterns in important sub-tropical forest ecosystems in Southern China. The research was conducted at Lutou forest research station, located in Yueyang, Hunan Province, China. Soil samples were collected at 0–10, 10–20, and 20–40 cm depths from natural broadleaved forest (NBF), coniferous monoculture plantations (CPF), and mixed forest stand. CPF stands are directly affected by human interference and frequent harvesting practices, whereas mixed forest and NBF stands are naturally grown forests with minimal human interference. Enzymes continually play a positive role in preserving soil health. The results showed that the interaction effect of forest type and soil depth significantly influenced urease, sucrase, and protease activity (all p &lt; 0.001); however, no clear patterns were observed. Soil microbial carbon (MBC) and soil microbial nitrogen (MBN) were remarkably higher in 0–10 cm in mixed forest and NBF stand compared to CPF stand. For the upper soil layer, soil organic carbon (SOC) was higher in mixed forest, whereas, for the remaining two layers, it was observed to be highest in NBF. Moreover, the microbial quotient (MBC/SOC) was considerably higher in NBF forest in all soil layers than in mixed forest and CPF stand. Soil organic carbon (SOC) and soil total nitrogen (TN) had a strong positive relationship with MBC compared to MBN. Our study contributes toward an enhanced understanding of soil enzymatic responses and microbial soil dynamics’ biological patterns, controls, and activities in different rural forest ecosystems.

Short-term effects of retention forestry on the diversity of root-associated ectomycorrhizal fungi in Sakhalin fir plantations, Hokkaido, Japan

We have examined the effects of dispersed and aggregated retention on the diversity of root-associated ectomycorrhizal fungi (EcMf) in Sakhalin fir (Abies sachalinensis) plantations, 4 years after logging. Roots of Sakhalin fir seedlings and the adjacent broadleaved or Sakhalin fir trees were sampled in broadleaved dispersed retention sites (10, 50, or 100 trees/ha), conifer aggregated retention sites (a single 60 × 60 m square patch of Sakhalin fir trees per site), clear-cut sites, unharvested Sakhalin fir plantations, and natural broadleaved forest stands. The EcMf on the roots were grouped into operational taxonomic units based on the similarity of the internal transcribed spacer sequences within the nuclear ribosomal DNA. Clear-cutting significantly reduced the species richness and diversity of the EcMf and altered the species composition when compared with the unharvested Sakhalin fir plantations and natural broadleaved forests. In contrast, both the aggregated and dispersed retention sites maintained higher levels of EcMf diversity, as well as different EcMf communities when compared with the clear-cut sites. Aggregated retention was effective at conserving EcMf diversity at the unharvested Sakhalin fir plantations, but the effects were limited within retained patches. Broadleaved dispersed retention did not retain the EcMf communities that were present prior to logging even at high retention levels, but they could retain unique EcMf communities, which differed between the Sakhalin fir plantations, natural broadleaved forests, and clear-cut sites. The species richness and diversity values for some of the dispersed retention sites were comparable to the values for the unharvested Sakhalin fir plantations and tended to be greater than the values for the aggregated retention sites. The results indicate that dispersed retention could be an effective strategy by which to preserve a larger number of EcMf species and unique EcMf communities in logged conifer plantations, although the positive effects were likely limited spatially within the rooting zones of the retained broadleaved trees. Finally, naturally regenerating Sakhalin fir seedlings were found to share a large amount of their EcMf with adjacent broadleaved retention trees, indicating that multi-host EcMf of retained trees largely contribute to ectomycorrhizal colonization of the surrounding regenerated seedlings in the logged areas. Our findings demonstrated that both dispersed and aggregated retention methods could be used to mitigate the impacts of logging on EcMf diversity in Sakhalin fir plantations, in Japan, and that there were large differences in the effects among the different retention methods.

The negative effect of Chinese fir (Cunninghamia lanceolata) monoculture plantations on soil physicochemical properties, microbial biomass, fungal communities, and enzymatic activities

Considerable natural or secondary forests have been converted to plantations in response to the growing needs for timber, paper, and fuel. Soil fungal communities are sensitive to ecosystem transformation and play an important role in aboveground-belowground linkages and biogeochemical cycling. However, the effect of forest conversion on fungal community structure and functions and driving mechanisms remains unclear. We investigated the response of soil fungal communities and the corresponding change in soil physicochemical biological properties and enzymatic activities to the natural broad-leaved forest (NBF) converted to the Chinese fir (Cunninghamia lanceolata) plantation (CFP) in subtropical China with ITS rRNA amplicon sequencing. Soil physicochemical properties, microbial biomass, fungal alpha diversities, and enzymatic activities decreased with forest conversion, including pH, soil water content, soil organic carbon, available phosphorus, total nitrogen, nitrate nitrogen, microbial biomass carbon and nitrogen, urease, protease, and acid phosphatase. Fungal community composition and structure were also strongly affected by forest conversion. Ascomycota had a higher read abundance in the NBF, but Basidiomycota showed a higher read abundance in the CFP. The read abundance of saprotroph and arbuscular mycorrhizal fungi increased with forest conversion, while that of ectomycorrhizal fungi decreased. Some fungal guilds—dung saprotrophs, lichenized fungi, endophytes, and lichen parasites—were even nearly lost in the CFP. These changes in fungal communities are all closely correlated to soil physicochemical properties, microbial biomass, and enzymatic activities. Overall, our study emphasizes the negative effect of the NBF conversion to the CFP on C, N, and P cycling mediated by fungi—and recommends replacing monoculture coniferous forests with mixed forests in reforestation to improve soil degradation.

Unravelling Trait-Environment Relationships at Local and Regional Scales in Temperate Forests.

Understanding the trait–environment relationships has been a core ecological research topic in the face of global climate change. However, the strength of trait–environment relationships at the local and regional scales in temperate forests remains poorly known. In this study, we investigated the local and regional scale forest plots of the natural broad-leaved temperate forest in northeastern China, to assess what extent community-level trait composition depends on environmental drivers across spatial scales. We measured five key functional traits (leaf area, specific leaf area, leaf carbon content, leaf nitrogen content, and wood density) of woody plant, and quantified functional compositions of communities by calculating the “specific” community-weighted mean (CWM) traits. The sum of squares decomposition method was used to quantify the relative contribution of intraspecific trait variation to total trait variation among communities. Multiple linear regression model was then used to explore the community-level trait–environment relationships. We found that (i) intraspecific trait variation contributed considerably to total trait variation and decreased with the spatial scale from local to regional; (ii) functional composition was mainly affected by soil and topography factors at the local scale and climate factor at the regional scale, while explaining that variance of environment factors were decreased with increasing spatial scale; and (iii) the main environment driver of functional composition was varied depending on the traits and spatial scale. This work is one of the few multi-scale analyses to investigate the environmental drivers of community functional compositions. The extent of intraspecific trait variation and the strength of trait–environment relationship showed consistent trends with increasing spatial scale. Our findings demonstrate the influence of environmental filtering on both local- and regional-scale temperate forest communities, and contribute to a comprehensive understanding of trait–environment relationships across spatial scales.

Response of soil microbial community to plant composition changes in broad-leaved forests of the karst area in Mid-Subtropical China.

The rapid growth and expansion ofCryptomeria japonica (Thunb. ex L. f.) D. Don in karst area strongly affects plant composition of native deciduous broad-leaved forest, which seriously threat ecosystem function and service. Given the importance of soil microorganisms in regulating nutrients cycling and plant species coexistence, understanding soil microbial attributes and their relationships with soil and vegetation features in forests harboring different C. japonica abundance will help understanding the drivers of ecosystem function changes. Here we examined the diversity and composition of soil bacterial and fungal communities and their correlations with plant diversity as well as soil physicochemical properties in karst broad-leaved forests with different relative abundances of C. japonica (i.e., a high, moderate, low and no proportion level with a stem density of 1,487, 538, 156 and 0 plant/hm2, respectively) in Mid-Subtropical China. We found that soil pH decreased while soil water content (SWC), total nitrogen (TN), total phosphorus (TP) and total potassium (TK) tended to increase with the increase in C. japonica abundance. In contrast, soil available nitrogen (AN), available phosphorus (AP) and available potassium (AK) content declined by 26.1%∼49.3% under the high level of C. japonica abundance. A gradual decrease in relative abundance of Acidobacteria and Chloroflexi while a pronounced increase in relative abundance of Ascomycota and Basidiomycota were observed with increase of C. japonica abundance. Alternations in bacterial composition were closely related to changes in AP and AK, while the change of fungal structure was mainly related to SWC, soil organic carbon (SOC) and pH, indicating that bacterial community was sensitive to declines in soil available nutrients and fungal structure was sensitive to changes in soil physicochemical properties (i.e., pH and SWC) and organic carbon resource. Understory plants had the highest α-diversity in forest containing moderate abundance of C. japonica, which might be related to the high bacterial diversity. Our findings suggest conservation of soil bacterial and fungal taxa that are responsible for nutrients availability and carbon sequestration is of great significance for improving the resistance of natural deciduous broad-leaved forests to the rapid spread of C. japonica in karst areas. Moreover, Acidobacteria, Chloroflexi, Ascomycota and Basidiomycota are potential indicators for soil properties changes, which should be taken into consideration in karst forest managements.

The Effect of the Conversion from Natural Broadleaved Forests into Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) Plantations on Soil Microbial Communities and Nitrogen Functional Genes

The conversion of forests could change soil characteristics and, in turn, impact the microbial community. However, the long-term effect of forest transformation on bacterial and archaeal composition and diversity, especially on nitrogen functional communities, is poorly understood. This study aimed to explore the response of soil bacterial and archaeal communities, as well as nitrogen functional groups, to the conversion from natural broadleaved forests to Chinese fir (Cunninghamia lanceolate (Lamb.) Hook.) plantations in subtropical China by 16S rRNA amplicon sequencing. Except for soil bulk density (BD) and ammonium nitrogen (NH4+–N) content, other soil properties all decreased with the conversion from natural forests to plantations. Alpha diversity of bacteria and archaea declined with the transformation from natural forests to plantations. The composition of bacteria and archaea was significantly different between natural forests and plantations, which could be mainly attributed to the change in the content of soil organic carbon (SOC), total nitrogen (TN), nitrate nitrogen (NO3−–N), and available phosphorus (AP). The conversion of natural forests to plantations decreased the gene copies of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), and nifH (nitrogen fixation function) but increased denitrification gene copies (i.e., nirS, nirK, and nosZ). In summary, our study emphasizes the long-term negative effect of the conversion from natural broadleaved forests into Chinese fir plantations on the diversity and richness of soil microbial communities, thereby deeply impacting the cycling of soil nitrogen.

Is the Japanese walnut (Juglans ailantifolia, Juglandaceae) native to Sakhalin Island?

The Japanese walnut (Juglans ailantifolia Carrière) is considered a very rare native tree species to Sakhalin Island. There is no information about J. ailantifolia records in the natural broad-leaved mixed forests of the island. The valleys of the Uglegorka and the Nadym Rivers in the Uglegorsk administrative district were noted as the main habitats areas of J. ailantifolia in several sources. We found that all walnut trees from these locations belong to artificial forest stands over 95 years old. We conclude that J. ailantifolia is a non-native species to the modern flora of Sakhalin and was introduced from Japan at the beginning of the XX century.

Seed rain and soil seed bank in Chinese fir plantations and an adjacent natural forest in southern China: Implications for the regeneration of native species.

The natural regeneration of native broadleaved species underneath forest monoculture plantations is important to recover ecosystem functions and to mitigate adverse environmental effects. To understand how seed rain and soil seed bank facilitate natural regeneration, we surveyed their density and composition in a monoculture Chinese fir plantation, a mixed Chinese fir–broadleaf plantation, and an adjacent natural broadleaved forest for two years in southern China. Twenty‐eight species (16 families) were in seed rain, and 45 species (27 families) were in soil seed bank. Seed rain density did not differ significantly across stands; however, the number of taxa in seed rain was highest in the mixed plantation and lowest in the natural forest. Seed bank density was significantly higher in the mixed plantation than in the other stands (p < .05). The Sørensen similarity index of species composition between seed sources and aboveground vegetation were relatively low (<.50). The seeds of various native tree species were common in the seed bank of the plantations, indicating that seed rain and seed bank played an important role in native forest regeneration. We recommend that managers interested in sustainable forestry should take into consideration the presence of existing soil seed bank when developing their management strategies. In addition, with regard to forest regeneration process, we also recommend supplementation of the species composition by direct seeding or planting of desired species.

元江-李仙江流域亚洲象生境适宜性评价——基于荟萃分析和遥感大数据分析

PDF HTML阅读 XML下载 导出引用 引用提醒 元江-李仙江流域亚洲象生境适宜性评价——基于荟萃分析和遥感大数据分析 DOI: 10.5846/stxb202106241680 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 第二次青藏高原综合科学考察研究（2019QZKK0402）；国家自然科学基金项目（41971239，41461017） Habitat suitability evaluation of Asian elephants in the Yuanjiang-Lixianjiang River Basin based on meta-analysis and remote sensing big data Author: Affiliation: Fund Project: The second comprehensive scientific expedition to the Qinghai-Tibet Plateau(2019QZKK0402);The National Natural Science Foundation of China(41971239，41461017) 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:生境适宜性评价是物种保护和生境管理与规划的基础。近几十年来，云南境内野生亚洲象数量剧增，外扩迁移事件频发，而新迁入区域生境适宜状况因物种出现点数据缺乏而难以评价，掣肘迁移亚洲象保护与风险防范应急。以亚洲象新近迁入的元江-李仙江流域为案例区，采用荟萃分析统计亚洲象生境评价因子，结合相关性分析和方差膨胀因子独立性检验，筛选出生境评价因子；基于开源遥感数据产品量化生境因子，综合主成分分析和层次分析计算生境评价因子权重，采用生境适宜性指数（Habitat Suitability Index，HSI）模型评价元江-李仙江流域亚洲象生境适宜性，并分析其景观格局。结果表明：（1）元江-李仙江流域亚洲象生境适宜性空间格局主要表现为由下游至上游呈递减趋势，最适生境主要分布于流域下游段，而流域上游段适宜生境少；（2）元江流域生境适宜性低于李仙江流域，且其生境斑块连接度更低、破碎化更严重；（3）2021年"北移象群"北迁沿程生境适宜性由西南向东北呈下降趋势。基于亚洲象生境适宜性评价结果，科学引导野生亚洲象迁入适宜生境区，以规避人象冲突，保障外迁亚洲象群及其活动区居民生命财产安全，服务于区域生物多样性保护与乡村振兴。 Abstract:Habitat suitability evaluation is a basis for species conservation, habitat management and planning. Over the past decades, the number of wild Asian elephants in Yunnan Province of China has increased sharply, and elephants' emigration from their original habitats frequently occurred. However, habitat quality in the newly inhabited areas is often poorly known due to lack of records in presence of Asian elephants, which hinders Asian elephant protection and risk prevention. The rapid development of remote sensing big data mapping technology provides new data sources for habitat suitability evaluation studies, and offers the possibility of identifying suitable habitats for species on a large regional scale more accurately and finely. In this study, a remote sensing big data-driven habitat suitability evaluation system for Asian elephants is constructed. We selected the Yuanjiang-Lixianjiang River Basin newly immigrated by Asian elephants as a case area, used meta-analysis to search for environmental factors related to Asian elephants habitat evaluation, and screened out habitat suitability evaluation factors by combining correlation analysis with variance inflation factor test. Subsequently, all habitat suitability evaluation factors were quantified based on open-source remote sensing data products and their weights were calculated using principal component analysis and analytic hierarchy process. Finally, we used a Habitat Suitability Index (HSI) model to determine the habitat suitability of Asian elephants in the study area and analyzed landscape patterns of habitats of Asian elephants. The results show that (1) the habitat suitability of Asian elephants in the Yuanjiang-Lixian River Basin decreased gradually upstream. The optimal habitat mainly occurred in the downstream basin, with a small distribution in the midstream basin and almost no distribution in the upstream basin. (2) The Yuanjiang River Basin was less suitable for Asian elephants than the Lixian River Basin because it had less connected and more fragmented habitat patches, which cannot meet the minimum home range requirements of Asian elephant populations and make it difficult to sustain a long-term survival of the "northward migration elephant herd". (3) The habitat suitability decreased along the northward migration route of elephant herd called "northward migration elephant herd" roaming in 2021 with the decreased distribution of natural broad-leaved forests along the way. The findings provide a basis for scientifically guiding the elephant herd into suitable habitats to avoid the conflicts between the human and wild elephant and thereby to ensure the safety of the elephant herd and the affected residents, which will serve for the regional biodiversity conservation and rural revitalization. 参考文献 相似文献 引证文献

Comparison of density and basal area estimation of mountain natural forests based on distance-based sampling methods in Zhejiang, China

ObjectiveThe sustainable development of forest ecology and forest management practices is inseparable from the support of forest surveys. Different sampling methods have an unavoidable impact on the collection of natural community characteristic information. An appropriate method reduces the cost of the investigation to the maximum degree under the premise of ensuring accuracy. Distance-based sampling methods are widely used because of their excellent performance in estimating forest population characteristics. The purpose of this study is to compare and find an efficient sampling method of natural broad-leaved forests in mountainous areas of Zhejiang, China, which is of great significance to large-scale field survey practice in similar areas. MethodOur study used census survey data from fixed monitoring sample plots of natural broad-leaved forest in Wuyanling National Nature Reserve, Zhejiang, China as an example and simulated different distance-based sampling methods, including n-tree distance (NTD), point-centered quarter (PCQ), and T-square (Ts), combined with several estimators to estimate the stand density and basal area. The results were compared with the actual mean values of the 100% survey. ResultWe found that different sampling methods and estimators significantly influenced the results. NTD1 overestimated both the stand density and basal area, while NTD2 performed the best, with the lowest RMSE. Secondary performance was obtained with Ts3, Ts5, and Ts6, with small RMSEs of density and basal area. The RMSEs of the PCQ and Ts sampling methods based on a single distance were all large. ConclusionThe NTD sampling method with the NTD2 estimator is recommended to estimate the stand density and basal area for field investigation of natural forests in the Zhejiang mountainous area.

Changes in stand structure and biomass increment in a warm temperate forest at a long-term ecological research site in Korea over 17 years

Changes in stand biomass, stem density, mortality and recruitment were monitored from 2000 to 2016 at 5- or 6-year intervals of Mt. Geumsan (GMS). The GMS had 34 woody plant species and 2698 living stems (DBH ≥ 2 cm) ha−1 in 2016, with an increase in biomass from 233.80 ton ha−1 in 2000 to 282.15 ton ha−1 in 2016. The dominant species in the canopy layer was Quercus serrata, while Chamaecyparis obtusa was the dominant species in the subtree layer. During the 17 years, the biomass of Q. serrata increased from 156.35 to 198.40 ton ha−1, while the stem density of Q. serrata declined from 395 to 268 stems ha−1. In addition, the biomass of C. obtusa increased from 12.70 to 24.09 ton ha−1, and also the stem density of C. obtusa increased from 722 to 898 stems ha−1. The forest structure of GMS is expected to maintain dominance of Q. serrata, and C. obtusa is increasing. Therefore, GMS was a natural broad-leaved forest composed of Q. serrata, but natural broad-leaved species at the site are declining due to the regeneration and growth of C. obtusa, which is relatively shade-tolerant compared to other species.

Unraveling the Influence of Land-Use Change on δ13C, δ15N, and Soil Nutritional Status in Coniferous, Broadleaved, and Mixed Forests in Southern China: A Field Investigation.

Natural isotopic abundance in soil and foliar can provide integrated information related to the long-term alterations of carbon (C) and nitrogen (N) cycles in forest ecosystems. We evaluated total carbon (TC), total nitrogen (TN), and isotopic natural abundance of C (δ13C) and N (δ15N) in soil and foliar of coniferous plantation (CPF), natural broadleaved forest (NBF), and mixed forest stands at three different soil depths (i.e., 0–10, 10–20, and 20–40 cm). This study also explored how soil available nutrients are affected by different forest types. Lutou forest research station, located in Hunan Province, central China, was used as the study area. Results demonstrated that the topsoil layer had higher TC and TN content in the mixed forest stand, resulting in a better quality of organic materials in the topsoil layer in the mixed forest than NBF and CPF. In general, soil TC, TN, and δ15N varied significantly in different soil depths and forest types. However, the forest type did not exhibit any significant effect on δ13C. Overall, soil δ13C was significantly enriched in CPF, and δ15N values were enriched in mixed forest. Foliar C content varied significantly among forest types, whereas foliar N content was not significantly different. No big differences were observed for foliar δ15N and δ13C across forest types. However, foliar δ13C and δ15N were positively related to soil δ13C and δ15N, respectively. Foliar N, soil and foliar C:N ratio, soil moisture content (SMC), and forest type were observed as the major influential factors affecting isotopic natural abundance, whereas soil pH was not significantly correlated. In addition, forest type change and soil depth increment had a significant effect on soil nutrient availability. In general, soil nutrient availability was higher in mixed forest. Our findings implied that forest type and soil depth alter TC, TN, and soil δ15N, whereas δ13C was only driven by soil depth. Moreover, plantations led to a decline in soil available nutrient content compared with NBF and mixed forest stands.

Shed light in the dark – How do natural canopy gaps influence temperate bat diversity and activity?

Globally, forests are under pressure to cope with an increasing human demand for forest products, while the need to protect forest biota increases. Old-growth forests are reference systems for the study of natural structures and processes in forest ecosystems. Results from such studies can be used to derive management practices that support and even foster biodiversity.Most temperate bat species exhibit a high affinity towards forest habitats. We studied the foraging behaviour of temperate woodland bats in naturally created canopy gaps. The study took place in a large and coherent Central European lowland old-growth forest, the “Belovezhskaya Pushcha” in Belarus. We used passive acoustic recorders to assess the activity and diversity of bats in 12 natural canopy gaps and in adjacent forest interior control plots in two different forest habitats.We found that the activity of open-space foragers and narrow-space foragers did not differ between forest gaps and the adjacent forest interior. The activity of edge-space foraging bats was higher in forest gaps. Bat diversity in mixed-coniferous forest stands was higher in canopy gaps. Gap size differently influenced bat guild activity. While the activity of open-space and narrow-space foragers did not vary with gap size, the activity of the edge-space foragers declined in broadleaved forests with increasing gap size. Bat diversity decreased with increasing gap size only in broadleaved forests.Our results demonstrate the differential influence of small-scale disturbances in old-growth forests on temperate bat guilds. Furthermore, our study highlights the importance of native broadleaved forests for the temperate bat community.

Decline in nutrient inputs from litterfall following forest plantation in subtropical China

The rapid conversion of natural broadleaved forests to plantations (mainly Cunninghamia lanceolata and Pinus massoniana) in subtropical China has resulted in a substantial decline in soil fertility, but the biogeochemical mechanism behind this decline remains not fully understood. Litterfall is an important source of nutrients that are returned to soils through litter deposition and decomposition. We assessed various types of litterfall (leaves, twigs, flowers, fruits and unidentified litter) monthly and their carbon (C), nitrogen (N), phosphorus (P) and potassium (K) inputs to soils in a natural broadleaved forest (Castanopsis carlesii) and in P. massoniana and C. lanceolata plantations over 10 years. The total litterfall was 21–25% lower in plantations than in the C. carlesii forest, resulting in much lower C (−17% and −14%), N (−62% and −52%), P (−24% and −32%) and K (−53% and −40%) inputs from litterfall in the P. massoniana and C. lanceolata plantations. Leaves accounted for 72–76% of the total litterfall, so we compiled available data on the nutrient release from the three foliar litters during the 1st year of decomposition throughout subtropical China. The decomposition rates of P. massoniana and C. lanceolata needle litter were only half that of C. carlesii leaf litter, and the lower initial quality of P. massoniana and C. lanceolata needle litter relative to C. carlesii leaf litter resulted in significantly lower amounts of N (−95% and −76%) and P (−48% and −25%) being released. These results suggest that low nutrient (N, P and K) inputs due to low litter production and slow nutrient release due to slow litter decomposition are two important biogeochemical reasons for the decline in soil fertility in plantations in subtropical China.