Natural Vegetation Restoration Research Articles

Shifts in soil nutrient concentrations and C:N:P stoichiometry during long-term natural vegetation restoration.

BackgroundEcological stoichiometry (C:N:P ratios) in soil is an important indicator of the elemental balance in ecological interactions and processes. Long-term natural vegetation plays an important role in the accumulation and distribution of soil stoichiometry. However, information about the effects of long-term secondary forest succession on soil stoichiometry along a deep soil profile is still limited.MethodsWe selected Ziwuling secondary succession forest developed from farmland as the study area, investigated the concentrations and stoichiometry of soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) at a depth of 0–100 cm along a 90-year succession chronosequence, including farmland (control), grassland, shrub, early forest, and climax forest.ResultsSOC and TN concentrations significantly increased with increasing restoration age, whereas soil P concentration remained relatively stable across various successional stages. SOC and TN concentrations decreased with an increase in soil depth, exhibiting distinct soil nutrient “surface-aggregation” (high nutrients concentration in the top soil layer). The soil C:P and N:P ratios increased with an increase in restoration age, whereas the variation of the C:N ratio was small and relatively stable across vegetation succession. The nutrient limitation changed along with vegetation succession, transitioning from limited N in the earlier successional stages to limited P in the later successional stages.ConclusionOur results suggest that more nitrogen input should be applied to earlier succession stages, and more phosphorus input should be utilized in later succession stages in order to address limited availability of these elements. In general, natural vegetation restoration was an ecologically beneficial practice for the recovery of degraded soils in this area. The findings of this study strengthen our understanding of the changes of soil nutrient concentration and nutrient limitation after vegetation restoration, and provide a simple guideline for future vegetation restoration and reconstruction efforts on the Loess Plateau.

Justification of reclamation parameters for lands disturbed during the development of gold placers

The article deals with the issue of reclamation of lands disturbed during the development of gold placers. Using the results of surveys and studies of the rocks composing the surface layer, the authors compare the present state of disturbed lands and the technogenic relief designed by technical documents on the development of alluvial placers. The discrepancy between actual and design data is analyzed. The conditions of natural vegetation restoration are studied. Results of observations of the natural vegetation restoration within loose deposits are presented. Recommendations on flattening angles depending on the length of slopes and elevation differences between the bottom and crest of technogenic embankments are given. The design results for reclamation of disturbed lands based on preliminary surveys and mining project data are compared. Methods for reducing the amount of reclamation works are substantiated.

Monitoring the Diversity of Frogs and Toads (Amphibia: Anura) along Code River Province of Daerah Istimewa Yogyakarta

The research about frogs and toads diversity in the Code River, Province of Daerah Istimewa Yogyakarta (DIY) had been done in 2012 (Yudha et al, 2013). Now, after five years passed, we conduct monitoring activities to updating its diversity and distribution. After five years, we consider that there are many changes along the river that influenced habitat condition for frogs and toads which live along and near the river. Some of the changes are unused land became human settlement or paddy fields and waste land. The purpose of this research is to monitor the diversity of frogs and toads after five years along Code River. The method used was line transect combine with visual encounter surveys (VES) and river bank cruising. Results show that the species number of frogs and toads found in 2012 were slightly higher compare to 2017. The frogs and toads on upstream part were diverse in 2017 compare to 2012 due to natural restoration of riparian vegetation occur on upstream. The frogs and toads on midstream part were less diverse in 2017 compare to 2012 due to increasing human activities near the river and less riparian vegetation. The frogs and toads on downstream part were also less diverse in 2017 compare to 2012 due to increasing human activities near the river and more household waste stuck on riparian vegetation. There was variation of anurans diversity after five years due to changing on physical condition of the river and human activities near the river.

Impact of vegetation restoration on soil organic carbon stocks and aggregates in a karst rocky desertification area in Southwest China

The objectives of the study were as follows: (a) to determine the response of soil organic carbon (SOC) fractions to vegetation restoration; (b) to examine the contributions of aggregate-associated OC to total soil OC accumulation along vegetation restoration, (c) to identify the factors that affect SOC accumulation along natural vegetation restoration in a karst region in Southwest China. Four vegetation restoration stages, namely, grassland, shrubland, shrub-arbor mixed forestland, and arbor forestland, were compared with cropland (CL). Soil samples were collected at depths of 0–10 cm and separated into five aggregate size fractions. SOC, light fraction OC (LFOC), easily oxidizable OC (EOC), and aggregate-associated OCs were determined for different aggregate sizes and total soil. Natural vegetation restoration increased macroaggregate amount but decreased the fractions of meso- and microaggregates. Vegetation restoration significantly increased total SOC, EOC, and LFOC concentrations and stocks and soil aggregate-associated OC concentrations. The responses of EOC and LFOC in total soil and soil aggregates were more sensitive than those of SOC along with vegetation restoration. Aggregate-associated OC concentrations generally increased with a decrease in aggregate size. Macro- and microaggregate-associated OC stocks increased, but mesoaggregate-associated OC stocks decreased following the conversion of CL to a natural vegetation ecosystem. The increase in SOC stocks was primarily attributed to the macroaggregate-associated OC stocks and their changes. OC concentrations and stocks in total soil and the soil aggregates were significantly positively related to exchangeable calcium content. Vegetation restoration considerably affects the amount of soil aggregates, OC concentrations, and stocks in total soil and soil aggregates. Changes in OC concentrations and stocks can be more pronounced in the liable carbon fraction than in total SOC. The increase in SOC was mostly attributed to OC accumulation in macroaggregates. Exchangeable calcium also affected soil OC accumulation in total soil and soil aggregates.

Temporal Variation in Preferential Water Flow during Natural Vegetation Restoration on Abandoned Farmland in the Loess Plateau of China

The restoration of vegetation in abandoned farmlands is an effective approach to control soil erosion on the Chinese Loess Plateau. However, few studies have investigated the effect of natural restoration age on the infiltration patterns and preferential flow in soil layers. This study examined the effect of the temporal variations in the degree of preferential flow and their contribution on the total infiltration in abandoned farmlands restored with different vegetation communities. In total, four sites were investigated, namely site AF3, AF12, AF18 and AF25 of restoration age of 3, 12, 18 and 25 years, respectively. A traditional dye tracer experiment was adopted to visualize the water flow behavior in the four sites. A semi-variance analysis was conducted to interpret the spatial variability of the soil water induced by infiltration. The results showed that both the soil properties and the root systems improved with the increased natural restoration ages combined with the effect of the plant species. The degree of preferential flow from the lowest to the highest occurred in AF3, AF12, AF18 and AF25, which was mainly affected by the development of root systems. Also, the abundant lateral root and steeper slope may have caused the presence of lateral flow in AF18 and AF25. Meanwhile, the spatial variability of the soil water in the infiltration patterns through vertical soil profiles increased from AF3 to AF25. Compared to AF3, the infiltration volume through preferential pathways in AF12, AF18 and AF25 increased by 1.73 times, 1.94 times and 4.09 times, respectively. Therefore, the preferential flow was improved in abandoned farmland in the presence of natural vegetation restoration that can increase water storage in the deep soil layer and reduce surface runoff and erosion.

Long-term forest succession improves plant diversity and soil quality but not significantly increase soil microbial diversity: Evidence from the Loess Plateau

Many studies have focused on the processes of vegetation succession, however, the dynamics of soil microbes and the synergy between vegetation and soil are still poorly understood following vegetation succession. This study focused on a forest succession sequence including farmland, grassland, shrubland (i.e., Hippophae rhamnoides), pioneer forest (i.e., Populus davidiana), and climax forest (i.e., Quercus liaotungensis) on the Loess Plateau of China, to explore plant and soil changes, as well as soil microbial community dynamics. The results showed that litter biomass, soil organic carbon (SOC), total nitrogen (TN) and the ratio of SOC to TN exhibited an increasing trend in the whole process of the forest succession, and NH4+, microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), and the ratio of dissolved organic carbon (DOC) to dissolved organic nitrogen (DON) had significantly increased before the shrubland stage, and then they were going to be stable. During the forest succession, the main bacterial phyla present were Proteobacteria, Actinobacteria, and Acidobacteria, and the predominant fungal phyla were Ascomycota and Basidiomycota. The soil microbial community composition was stable and did not change significantly, but the bacteria and fungal communities were associated with specific plant or soil properties. It was proved that the change of soil microbial community was closely related to vegetation and soil community changes. The results suggested that long-term forest succession not only improves plant diversity, but also improves soil biology and quality, even though it does not significantly increase soil microbial diversity. The findings enhance the understanding of the impact of soil microbial ecological characteristics and provide an important guidance for the sustainable management of forest ecosystems following long-term natural vegetation restoration.

Natural vegetation restoration of Liaodong oak (Quercus liaotungensis Koidz.) forests rapidly increased the content and ratio of inert carbon in soil macroaggregates

The lack of clarity of how natural vegetation restoration influences soil organic carbon (SOC) content and SOC components in soil aggregate fractions limits the understanding of SOC sequestration and turnover in forest ecosystems. The aim of this study was to explore how natural vegetation restoration affects the SOC content and ratio of SOC components in soil macroaggregates (>250 μm), microaggregates (53–250 μm) and silt and clay (<53 μm) fractions in 30-, 60-, 90- and 120-year-old Liaodong oak (Quercus liaotungensis Koidz.) forests, Shaanxi, China in 2015. And the associated effects of biomasses of leaf litter and different sizes of roots (0–0.5, 0.5–1.0, 1.0–2.0 and >2.0 mm diameter) on SOC components were studied too. Results showed that the contents of high activated carbon (HAC), activated carbon (AC) and inert carbon (IC) in the macroaggregates, microaggregates and silt and clay fractions increased with restoration ages. Moreover, IC content in the microaggregates in topsoil (0–20 cm) rapidly increased; peaking in the 90-year-old restored forest and was 5.74 times higher than AC content. In deep soil (20–80 cm), IC content was 3.58 times that of AC content. Biomasses of 0.5–1.0 mm diameter roots and leaf litter affected the content of aggregate fractions in topsoil, while the biomass of >2.0 mm diameter roots affected the content of aggregate fractions in deep soil. Across the soil profile, macroaggregates had the highest capacity for HAC sequestration. The effects of restoration ages on soil aggregate fractions and SOC content were less in deep soil than in topsoil. In conclusion, natural vegetation restoration of Liaodong oak forests improved the contents of SOC, especially IC within topsoil and deep soil. The influence of IC on aggregate stability was greater than the other SOC components, and the aggregate stability was significantly affected by the biomasses of litter and 0.5–1.0 mm diameter roots in topsoil and >2.0 mm diameter roots in deep soil. Natural vegetation restoration of Liaodong oak forests promoted SOC sequestration by soil macroaggregates.

Quantifying effects of root systems of planted and natural vegetation on rill detachment and erodibility of a loessial soil

The objectives of this study were to evaluate different root parameters for estimating rill detachment, and to compare and quantify the effectiveness of planted and natural vegetation on soil physical characteristics and in reducing rill detachment and erodibility. Laboratory-concentrated-flow flume tests were performed under a flow discharge of 3 L min−1 and a slope of 15° with intact soil samples. A silt loam soil (Calcic Cambisol, in Loess Plateau in China) was sampled in 2015 from laboratory with planted ryegrass (Lolium perenne L.) and in 2014 from natural vegetation fields under 12 to 36-a restoration. The results indicated that root length density was the best parameter for estimating the effects of roots on rill detachment and erodibility for both planted ryegrass and natural vegetation, with exponential reduction equations. The exponents were more negative for natural vegetation (−0.411) than for planted species (−0.217) because of the existence of more complex root networks under more diverse natural vegetation. Rill erodibility of soil samples with roots decreased exponentially from the baseline erodibility of the root-free soil as RLD increased. Root systems of the restored natural vegetation ameliorated soil characteristics (bulk density, aggregate stability and organic matter content) more profoundly than those of the laboratory tests due to stronger bonding and binding effects, resulting in a lower absolute soil detachment rate for a given root density. There existed a vertical decay distribution pattern of root densities with soil depth for natural vegetation and planted ryegrass, and this distribution of root systems reached a steady state after 12 years natural vegetation restoration. More vegetation types under more different hydraulic conditions should be evaluated in future studies to provide better scientific bases for modelling their impacts on rill detachment and erodibility.

Responses of soil labile organic carbon fractions and stocks to different vegetation restoration strategies in degraded karst ecosystems of southwest China

The effective restoration of degraded areas, resulting in the sequestration of significant amounts of soil organic carbon (SOC) and labile soil organic carbon fractions (LOCF), is essential for mitigating global climatic changes. It is therefore important to improve our understanding of the responses and magnitudes of SOC and LOCF during restoration processes in degraded land like karst ecosystems. In this study, we selected four different restoration strategies: (1) not subjected to any management practices, mainly bare land (BL); (2) Pinus yunnanensis plantation (PY), native and characterized by slow growth and high drought resistance; (3) Eucalyptus maideni plantation (EM), non-native and characterized by rapid growth and high adaptability; (4) natural regeneration of secondary forest (SF). The SOC concentrations, SOC stocks, sensitive indicators of LOCF (microbial biomass C (MBC), permanganate oxidizable C (KMnO4-C), dissolved organic C (DOC), water soluble organic C (WSOC)), non-labile C (NLC), and the carbon pool management index (CPMI) were investigated. The different reforestation strategies had significant effects (p < 0.05) on SOC stocks; compared with BL, the SOC stocks of SF, EM, and PY increased by 57.7, 38.0, and 26.9%, respectively. Both the LOCF and the NLC stocks were significantly increased by the different restoration strategies relative to the BL, while natural vegetation restoration was more beneficial for C sequestration than afforestation. Compared with BL, in SF, EM, and PY, the CPMI increased by 70.1, 35.8, and 32.6%, respectively. These findings suggest that although afforestation can significantly increase C sequestration, natural regeneration may be a more effective approach in terms of SOC sequestration. Soil C accumulation would be limited by nitrogen and phosphorus during the vegetation restoration in the karst areas. In degraded karst ecosystems, the CPMI could be used as a representative index in evaluating the impacts of vegetation restoration on SOC concentration and soil quality.

Dynamics of soil microbial C:N:P stoichiometry and its driving mechanisms following natural vegetation restoration after farmland abandonment

Vegetation restoration after farmland abandonment has increased greatly and is commonly used to improve soil fertility and ecosystem service. Knowledge of soil community-level elemental homeostasis following natural vegetation restoration is specially limited for the abandoned farmlands. This study examined the changes in soil microbial biomass stoichiometry and homeostasis with a chronosequence of 3, 8, 13, 18, 23 and 30 years following natural vegetation restoration since farmland abandonment on the Loess Plateau, China. Vegetation communities, soil properties, microbial communities, and enzyme activities were analyzed to study the drivers on soil microbial C:N:P stoichiometry. The results showed that soil microbial biomass C: N ratios had little change following natural vegetation restoration since farmland abandonment, natural vegetation >23 years had significantly enhanced the microbial biomass C:P and N:P ratios by 26.1%–133.9% and 31.7%–67.4%, respectively. However, microbial biomass C:N, C:P and N:P ratios were constrained following natural vegetation restoration. Vegetation restoration for 30 years enhanced urease and alkaline phosphatase activities by 125.4% and 42.9%, respectively, which showed synchronous changes with N and P contents in microbial biomass. Soil fungi, urease and alkaline phosphatase were the drivers to the changes in microbial C:N:P stoichiometry. The results suggest that long-term vegetation restoration (>23 years) will aggravate microbial P limitation, however, soil microorganism maintained the homeostatic regulation of stoichiometric ratios to mitigate P limitation. Fungi played a strong role in shaping microbial community-level elemental homeostasis and nutrient cycling through releasing N-converting and P-converting enzymes into soil following natural vegetation restoration.

Vegetation patterns on a landslide after five years of natural restoration in the Loess Plateau mining area in China

Landslides represent the most intense type of geological disaster in the gully region of the Loess Plateau and have caused great damage to surface vegetation. Natural restoration is considered as an effective method for revegetation, however, vegetation patterns on landslides after natural restoration and its related factors remain poorly understood. The present study investigated vegetation patterns on a landslide after 5 years of natural restoration, which located in Hezhai coal mining area, Shanxi Province, China, to understand the natural restoration of vegetation after landslides. The species composition on the bottom, middle and top of the landslide, as well as the species importance value, plant diversity and similarity were ascertained and compared with the that on undisturbed site. Furthermore, the soil seed bank in another landslide which just experienced 0.5-year natural restoration was also investigated, and a seed bank germination experiment was performed based on the collected seed samples from the landslide to test their vitalities. Results showed that 20 species of vegetation were found on all three parts of the landslide, which all belonged to herbaceous plants and shrubs. Eleusine indica was dominant in both the bottom and middle of the landslide, while the top was dominated by Potentilla sischanensis. From the bottom to the top of landslide, the Margalef Index was 3.26, 3.91, and 2.17 respectively; the Shannon–Wiener Index was 2.56, 2.60, and 2.13 respectively; the Pielou Index was 0.55, 0.56, and 0.46, respectively. Species similarity revealed a close relationship between species compositions on restored landslide and undisturbed area. A total of 13 species of seeds were found in the soil seed bank, which were also similar to the aboveground plants on disturbed site and the landslide after 5-year natural restoration, and the seed was also proved vital in the seed bank experiment. These results indicated that vegetation on landslides could recovery naturally, and natural restoration was more effective on the bottom and middle of the landslide, which revealed that changes in topography could affect revegetation. The seed bank in the soil was considered as a main factor affecting natural restoration. This research provides useful insight into the natural restoration of vegetation after landslides, and provides a reference for the selection of ecological restoration strategies.

Species diversity of Arabis alpina L. communities in two Pb/Zn mining areas with different smelting history in Yunnan Province, China

In order to explore the species compositions and species diversity (Dominance (Do), Shannon-Wiener index (H′), Simpson diversity index (Dsi), Species richness (DMG), Pielou evenness index (Epi) and Frequency (Fr)) of twenty Arabis alpina L. var. parviflora Franch communities, field investigation was conducted in Huize county, Yunnan province, China. Some 20 A. alpina communities were distributed in two traditional smelting tailing piles of Minbingyingjiying (TST) and Shangduoduo village (SDD) with different Pb smelting history. The morphological characteristics (plant height, branch number, basal leaf length, basal leaf width and root morphology) of A. alpina, contents and accumulation characteristics of eight potentially toxic metals (As, Cd, Cr, Cu, Pb, Zn, Al, Fe) in soil and plants were analyzed. The results showed that the morphological characteristics of A. alpina were mean plant height 12.25 cm, the basal leaf length 17.69 cm, leaf width 5.40 cm, the total root length 117.86 cm plant−1, the root diameter 0.90 mm. The leaves of A. alpina in SDD were longer and narrower with higher plant height compared with in TST. The main companion plants of A. alpina were Sporobolus fertilis (Steud.) W. D. Clayt, Arenaria orbiculata Royle ex Edgew. et Hook. F. and Eulalia speciosa. (Debeaux). The H′ and Dsi were 0.56–2.04 and 0.44–0.95, respectively. The plant species numbers, H’, Dsi and Epi of A. alpina communities in TST were higher than those in SDD. Pb contents in shoot of two A. alpina samples were more than 1000 mg kg−1, Cd content in shoot of one A. alpina sample >100 mg kg−1 and Zn contents in shoot of seven A. alpina samples >10,000 mg kg−1 with the enrichment factors and transport coefficients greater than 1. The results indicate that A. alpina as a Zn, Pb and Cd hyperaccumulator, could be used for long-term phytoremediation of soils contaminated by Cd, Pb and Zn. Species diversity of A. alpina community during long-term natural vegetation restoration was high in the middle succession with single-peak model, and A. alpina would be dominant in the succession climax stage in potentially toxic metal contamination areas.

Long-term biodiversity monitoring of the spontaneous successions for the assessment of the artificial restoration progress on the quarries in Russian Arctic

The results of long-term monitoring observations of natural recovery successions in the tundra and forest-tundra zones in various sectors of the Russian Arctic are analyzed. Efficiency of works on accelerated nature restoration is evaluated. Particular attention is paid to the analysis of mistakes made in the quarries reclamation projects. The combined review of the accumulated experience in natural and artificial vegetation restoration allows us to offer some recommendations for effective restoration of nature. Key words: natural recovery, spontaneous succession, anthropogenic vegetation, disturbed sites, biodiversity monitoring, artificial restoration

Influence of pH, nitrogen and sulphur deposition on species composition of lowland and montane coniferous communities in the Tatrzanski and Slowinski National Parks, Poland

Abstract: Nitrogen and sulphur deposition is considered as a negative factor for biodiversity, usually leading to changes in species composition and structure of plant communities, and ultimately to the impoverishment of biodiversity. In this study we investigated the variation over time (2001, 2006, 2011) in species composition and structure of the understory vegetation at varying levels of sulphur and nitrogen deposition in two conifer plantations (>100 year-old) growing in different climate areas of Poland (Scots pine at the Slowinski National Park, northern seaside; Norway spruce at the Tatrzanski National Park, southern mountains). The structure of the floor vegetation at both sites changed markedly during the studied decade, as clearly confirmed by principal component analysis. Among the environmental variables analyzed (NH4+, NO3-, SO42-, pH in the throughfall and in soil solution sampled at two different depths), only nitrates were non-significantly correlated with PC axes. The results confirmed the negative effects of the concentration of both elements on undergrowth and tree recruitment in the coastal stand (Empetro nigri-Pinetum). On the other hand, in the mountain stand (Abieti-Piceetum) we observed an increase over time of nitrophilous species typical of the beech forest, which represent the natural vegetation of this area, suggesting a gradual natural restoration of the native vegetation in the long run.

Relationships between the characteristics of soil and understory in a Pinus massoniana forest in southern China

Soil is the basis for vegetation growth, and vegetation in turn improves soil quality. Understanding the relationships between soil and vegetation characteristics is needed to rehabilitate degraded land and implement sustainable land use practices. In particular, it is important to uncover the relationship between natural vegetation restoration and key soil parameters for the improvement of restored ecological environments. This study analyzed the relationships between soil and understory characteristics of a P. massoniana forest in degraded red soil in southern China. Red soils in this area have been severely eroded. The soils were categorized into three groups whose attributes differed significantly and each group was distributed within a topographical type. Understory and soil characteristics were closely correlated, but restoration of the understory was only related to some key soil attributes (e.g. available potassium content, pH, soil water content, bacteria amounts, and urease and catalase activities). Our results provide insight into the relationships between soil and vegetation characteristics for natural revegetation in degraded land with severely eroded soil.

Soil-Biogeochemical Aspects of Arable Farming in the Russian Federation

Soil-biogeochemical aspects of the current state of arable land in the Russian Federation are discussed. Considerable transformation of Russian agriculture has led to structural changes in the agricultural land use, including arable farming. About forty million hectares of former arable land have been abandoned and converted into the category of abandoned lands subjected to overgrowing with meadow and woody vegetation. The restoration of natural vegetation in postagrogenic ecosystems is accompanied by changes in the biological productivity and composition of vegetation on agricultural land in general. The reduction of plowlands and their transformation to abandoned lands have changed the carbon budget. In the early 1990s, arable farming was the net source of C-CO2. At present, the total arable land area in Russia is estimated at approximately 80 M ha. This area is a source of about 20 Mt C-CO2/yr. Forty million hectares of former arable land have turned into the sink of C-CO2 of about 40 Mt/yr in size. Thus, the entire agricultural land in Russia functions as the net sink for atmospheric CO2 at the rate of 20 Tg C/yr. This fact can be considered a contribution of Russian agriculture to the goals of the “soil 4 per mille” international program assuming carbon sequestration in agricultural soils. Changes in the agricultural land use patterns together with a sharp decrease in the application of all kinds of fertilizers have led to prevalent biogeochemical flux of nutrients (N, P, K) from arable soils to urbanized areas. The deficient nutrient budget implies that the soil-climatic potential and the potentials of other factors increasing farming productivity (new varieties, plant-protective chemicals, etc.) are not fully realized in agricultural production. In 25 years (1992–2016), the uptake of nutrients by crops from arable land comprised 91, 33, and 90 Mt for N, P2O5, and K2O, respectively. The amount of applied fertilizers in that period was only about 28 Mt for N, 10 Mt for P2O5, and 28 Mt for K2O. The highly deficient budget of phosphorus is of special concern. Under these conditions, it is necessary to significantly restrict the export of apatite concentrate and phosphate fertilizers as strategic (nonrenewable) resources necessary for ensuring the food security of Russia for decades ahead.

Driving force analysis of landscape pattern changes in Honghu Wetland Nature Reserve in recent 40 years

利用Landsat系列遥感影像数据（1974、1979、1984、1990、1996、2001、2006、2009、2014和2017年）解译得到的土地利用/土地覆盖变化（LUCC）结合研究区44年的气温、降水量、水位等气象水文数据，构建LUCC经验统计模型和计算景观格局指数，探讨1974-2017年洪湖国家级自然保护区景观格局变化的主要驱动因素.研究结果表明：土地利用强度指数由1974年的207增加到2017年的249.36，人类开发利用湖滨带的程度增强，到2017年约有30%的自然湿地转化为坑塘、农田和滩地及建设用地.不同地表覆盖类型的景观格局指数均发生了较大变化，2000年以后湖滨带逐渐形成了以养殖为主的低矮围景观.总体上景观趋于破碎化、连通性降低、稳定性变弱.洪湖湿地自然保护区土地利用强度指数与景观格局综合指数呈较显著的正相关，两者的相关系数为0.84，土地利用强度增加则景观更加破碎、斑块之间的连接程度减弱、区域的景观聚集度下降和景观异质性增加.总体而言，洪湖湿地自然保护区受人为干扰影响明显，开展封湖育草自然恢复与建立植被恢复示范区相结合，构建自湖滨至湖心的梯度变化完整的湿生植被-挺水植被-漂浮植被-浮叶植被-沉水植被的水生植物群落，退耕还草、退垸还湖、修复湖滨带植被，大幅度提高洪湖的自净能力，增加其水生植物多样性，实现湿地的有效修复，改善其结构和功能，维系洪湖湿地生态系统的平衡.;This study took Honghu National Nature Reserve as an example to investigate the driving forces on Landscape pattern changes based on the land use and land change data of 1974, 1979,1984, 1990, 1996, 2001, 2006, 2009, 2014 and 2017, which were obtained from interpretation of Landsat images. Correlation analysis was adopted for finding characteristics of the interaction by combining with meteorological hydrological data such as temperature, precipitation and water stage. The results showed that:Land use intensity index risen from 207 at the begining of the study to 249.36 at the end of the study during the period of 1974-2017, these changes were more due to enlargement in the interference of human activities for land-use change. About 30% of the natural wetlands translated into ponds, farmland and bottomland and construction land by 2017. The landscape pattern indices of different types have changed greatly, the lakeside zone has formed a low enclosed ponds dominated by aquaculture after entering twenty-first Century. On the whole, landscape tended to be diversified, fragmented, reduced in connectivity and weakened in stability. The correlation coefficient between land use intensity index and the composite index of landscape pattern is 0.84, it shows that LUCC is very closely related to the landscape pattern. With the increase of land use intensity, the landscape is more fragmented, the degree of connectivity between patches is weakly, the landscape aggregation degree of the area is decreasing, and the landscape heterogeneity is increasing. In general, the Honghu Wetland Nature Reserve is affected obviously by human interference. The goal of maintaining the balance of Honghu wetland ecosystem is achieved through rational exploitation and utilization, returning farmland to grass and lake, restoring the vegetation of the lakeside zone, increasing the diversity of its aquatic plants, realizing the effective restoration of the wetland, improving its structure and function. A combination of the natural restoration of vegetation and the establishment of demonstration area of vegetation restorations is carried out, and the hygrophilous vegetation, emergent aquatic vegetation, floating vegetation, floating-leaved vegetation, and submerged vegetation, should be constructed from the lakeside to the heart of the lake.

Theoretical Study on Self‐Organization of Vegetation Patterns Triggered by Water Resource in Deposited Sediment Layer

This research focuses on the self‐organization of vegetation patterns on severely degraded eroding lands, triggered by water resource in the deposited sediment layer on which the vegetation patterns are formed. A nonlinear spatiotemporal model is developed with the consideration of the interactions between vegetation biomass and water resource stored in the sediment layer. With employment of the model, the conditions for pattern formation of the considered ecological system are determined via Turing instability analysis. Numerical simulations of the research demonstrate the formation of banded, labyrinth, and gapped vegetation patterns, with the parameter values taken from the literature. The characteristics of the vegetation patterns are analyzed. Comparing the characteristics of the vegetation patterns of this research with that available in literature, great similarity of pattern formation is shown. The results obtained provide a theoretical comprehension on natural vegetation restoration of severely degraded eroding lands.

Controls of soil and aggregate‐associated organic carbon variations following natural vegetation restoration on the Loess Plateau in China

AbstractNatural vegetation restoration can enhance soil organic carbon (SOC) sequestration, but the mechanisms and control factors underlying SOC sequestration are still unknown. The objectives of the study are to quantify the temporal variation of soil and aggregate‐associated organic carbon (OC) and identify factors controlling the variation following natural vegetation restoration after farmland abandonment. We collected soils from sites having 5, 30, 60, 100, and 160 years of a natural vegetation restoration chronosequence after farmland abandonment in the Loess Plateau, China. The results showed that natural vegetation restoration increased macroaggregates (0.25–2 mm; 46.6% to 73.9%), SOC (2.27 to 9.81 g kg−1), and aggregate OC (7.33 to 36.98 g kg−1) in the top 20‐cm soil compared with abandoned farmland, and the increases mainly occurred in the early stage (&lt;60 years). The increase of SOC was contributed by OC accumulated in macroaggregates (0.25–2 mm) rather than microaggregates (≤0.25 mm). Moreover, SOC sequestration in the topsoil (0–10 cm) was mainly determined by fine root biomass (FR), labile organic carbon (LOC), and microbial biomass carbon (MBC). And in the subsoil (10–20 cm), SOC sequestration was mainly determined by the proportion of macroaggregates. The results suggest that natural vegetation restoration increased SOC and aggregate OC, and FR, MBC, LOC, and the physical protection of aggregates played important roles in regulating SOC and aggregate OC.

Surveying in highly-modified landscapes to document the occurrence of threatened species: a study of the giant armadilloPriodontes maximusin central Brazil

AbstractStudies on threatened species in highly modified and unprotected landscapes are necessary for the development of appropriate conservation policies. This is particularly important for species with large home ranges, such as the giant armadilloPriodontes maximus, whose occurrence in anthropogenic landscapes is poorly known despite its categorization as Vulnerable on the IUCN Red List. We searched and surveyed for the giant armadillo within human-modified areas in central Brazil using direct and indirect methods across a wide region dominated by diverse farming environments and scattered remnants of natural vegetation. During a 14-year period (2003–2016), we located 54 records of the species, including three road-kills and two instances of poaching. Most of the occurrence points (83%) were in native vegetation, with 17% in anthropogenic environments (pastures and roads). We confirmed the presence of the giant armadillo within a wide, intensely human-altered region. These findings indicate that Cerrado and Atlantic Forest remnants in modified landscapes in central Brazil play an important role as refuges for this armadillo species. In addition to habitat loss, road-kills and poaching persist as threats to the giant armadillo. Conservation actions are necessary to minimize human impacts and facilitate the persistence of the giant armadillo in this region. Policies that both deter illegal deforestation and strengthen incentives for the protection of natural vegetation remnants and restoration of biological corridors such as gallery forests would aid conservation of the giant armadillo in this area.