Natural Vegetation Succession Research Articles

The effect of mosses on the relocation of SOC and total N due to soil erosion and percolation in a disturbed temperate forest

Forests cover one-third of the global land and are important components of carbon and nitrogen cycling. Anthropogenic disturbances, such as forest road systems or skid trails for timber harvesting, can dramatically change the nutrient cycling in these ecosystems. Skid trails increase soil erosion and thus the displacement of soil organic carbon (SOC) and total nitrogen (Nt). Additionally, runoff transports high amounts of dissolved organic carbon (DOC), which can have a negative impact on aquatic ecosystems. One of the most important countermeasures against soil erosion is the quick recolonization of vegetation. To date, the extent to which natural vegetation succession influences the relocation of SOC and Nt, and in particular the role of mosses in this context, has not been well investigated. This study investigates the influence of natural vegetation succession and in particular of mosses on the displacement process of SOC and Nt as well as DOC caused by soil erosion. To this end, we combine the results of a field study using in-situ rainfall simulations with small-scale runoff plots in skid trails of the Schönbuch Nature Park in southwestern Germany with the results of ex-situ rainfall simulation experiments with infiltration boxes containing the substrate from the respective skid trails. The eroded sediments of skid trails were on average enriched in SOC by 16% and in Nt by 35% compared to the original soil, which lead to a decrease of the C/N ratio in sediments. As vegetation succession progressed, the displacement of SOC and Nt was reduced, confirmed by a negative correlation between the enrichment ratios of SOC (ERSOC), Nt and total vegetation cover. However, mosses tended to reduce ERSOC more than vascular plants. Additionally, mosses significantly decreased DOC concentration in surface runoff compared to bare soils, while no difference in DOC concentration in percolated water could be observed. Future research should explore the role of mosses in the storage of SOC and Nt in the soil and their impact on soil stability. Thus, utilizing mosses could potentially minimize environmental impacts from soil disturbances in forests.

Anthropogenic restoration exhibits more complex and stable microbial co-occurrence patterns than natural restoration in rubber plantations

Forest restoration is an effective method for restoring degraded soil ecosystems (e.g., converting primary tropical forests into rubber monoculture plantations; RM). The effects of forest restoration on microbial community diversity and composition have been extensively studied. However, how rubber plantation-based forest restoration reshapes soil microbial communities, networks, and inner assembly mechanisms remains unclear. Here, we explored the effects of jungle rubber mixed (JRM; secondary succession and natural restoration of RM) plantation and introduction of rainforest species (AR; anthropogenic restoration established by mimicking the understory and overstory tree species of native rainforests) to RM stands on soil physico-chemical properties and microbial communities. We found that converting tropical rainforest (RF) to RM decreased soil fertility and simplified microbial composition and co-occurrence patterns, whereas the conversion of RM to JRM and AR exhibited opposite results. These changes were significantly correlated with pH, soil moisture content (SMC), and soil nutrients, suggesting that vegetation restoration can provide a favorable soil microenvironment that promotes the development of soil microorganisms. The complexity and stability of the bacterial-fungal cross-kingdom, bacterial, and fungal networks increased with JRM and AR. Bacterial community assembly was primarily governed by stochastic (78.79 %) and deterministic (59.09 %) processes in JRM and AR, respectively, whereas stochastic processes (limited dispersion) predominantly shaped fungal assembly across all forest stands. AR has more significant benefits than JRM, such as a relatively slower and natural vegetation succession with more nutritive soil conditions, microbial diversity, and complex and stable microbial networks. These results highlight the importance of sustainable forest management to restore soil biodiversity and ecosystem functions after extensive soil degradation and suggest that anthropogenic restoration can more effectively improve soil quality and microbial communities than natural restoration in degraded rubber plantations.

Assessment of organic matter state and physical properties of postagrogenic sod-podzolic soil and its arable analogue

Land is often withdrawn from agriculture for various reasons, about 1/4 of the world’s fallow land is in Russia, mainly in the taiga forest zone. Some changes, determined by a combination of various factors, take place in fallow land. Therefore, in order to determine the expediency or priority of returning fallow land to arable land, it is relevant to assess the main indicators of its fertility. To this end, a comparative study of the organic matter and physical properties of an arable sod-podzolic soil and its post-agricultural analogue, which has been fallow for more than 20 years, was carried out. A reliable increase in the carbon content of the light fraction of organic matter in the 0-10 cm layer of the fallow soil was observed in comparison with the corresponding horizon of the arable analogue. In the 10-20 cm horizon this increase was manifested in the form of a tendency, also the tendency of increase in the content of organic carbon (total humus) in the former arable layer of the fallow soil was manifested. The increase in these indicators of the state of organic matter is apparently due to the increase in the amount of plant residues as a result of the succession of natural herbaceous vegetation compared to the amount of post-harvest residues on arable land. The fallow soil also showed an increase in the number of macroaggregates, agronomically valuable aggregates and the water holding capacity of macroand microaggregates compared to the arable soil. Obviously, such an improvement in the structural condition indicators is related to the increase in humus content and the absence of mechanical tillage, which favours the destruction of aggregates. The fallow soil in comparison with the arable soil had reliably lower density and density of solid phase, which is explained by higher content of light fraction of organic matter in it, as well as better structure. The obtained results allow to assess the nature of changes in fertility indicators of sod-podzolic soil as a result of staying in fallow condition. The indicator of the content of the light fraction of organic matter is an earlier indicator of the recovery of the fallow soil compared to the total carbon content in the soil, which allows to determine the expediency and priority of the return of fallow soils to arable land.

Natural Vegetation Succession Under Climate Change and the Combined Effects on Net Primary Productivity

AbstractClimate change and the resulting natural vegetation succession can alter vegetation productivity. However, the mechanisms underlying future productivity changes under the two influences remain unclear. Here, we used the comprehensive sequence classification system to simulate changes in global potential natural vegetation under different climate scenarios (SSP1‐2.6, SSP2‐4.5, SSP3‐7.0, and SSP5‐8.5), and combined the Carnegie–Ames–Stanford Approach model with random forest to assess the response of net primary productivity (NPP) to climate change and vegetation succession from 2020 to 2100. Except for SSP126, terrestrial NPP in 2100 decreased by 0.86, 2.39, and 2.54 Pg C·a−1 versus 2020 under SSP2‐4.5, SSP5‐8.5, and SSP3‐7.0, respectively. Forest was the primary contributor to terrestrial NPP changes. The total forest area was projected to increase under all scenarios, with SSP2‐4.5 showing the largest increase (358.57 × 104 km2). However, expanding forest regions exhibited a relatively low mean NPP, while stable regions demonstrated a declining pattern. Consequently, forest NPP increased under SSP1‐2.6 but decreased by 4.03, 3.43, and 0.82 Pg C·a−1 in 2100 versus 2020 under SSP5‐8.5, SSP3‐7.0, and SSP2‐4.5, respectively. In comparison, grassland and desert exerted minor influence on terrestrial NPP changes, their total NPP decreased only under the SSP1‐2.6 scenario. The grassland area decreased, but the mean NPP increased, whereas the desert area expanded, resulting in consistent changes in both total and mean NPP. Our results analyzed the effects of climate change and vegetation distribution under its influence on the change of NPP, which can deepen our understanding of their relationship.

Transformational processes in post-technogenic ecosystems of Kolomyia lignite and Yaziv sulfur deposits in Western Ukraine

Restoration of post-tech ecosystems of the Western region of Ukraine takes place both through natural self-overgrowth with vegetation and through the implementation of phytomeliorative measures - artificial afforestation of disturbed areas. These processes have been studied on post-technogenic territories of Kolomyia lignite and Yaziv sulfur deposits. Transformational processes in the study area are caused mainly by three factors: natural succession of vegetation (from the emergence of mosses and pioneering species of grasses and trees to the formation of stable plant communities); human economic activity (phytomeliorative measures for sowing grasses and creating forest crops) and cattle grazing (appearance of fruit tree species in phytocenoses). Transformational processes in edaphotopes are primarily determined by two factors - the natural succession of vegetation and erosion processes. Due to the long process of restoration of disturbed ecosystems in post-man-made areas, relatively complex and rich in species composition stable plant communities are gradually formed, which contribute to the formation of embriozems, identification of soil genetic horizons, increasing the thickness of the soil profile and approximating the physical and mechanical properties of the upper layers of the soil to the properties of natural zonal soils. The species composition and structure of vegetation in the post-technogenic territories of Kolomyia lignite and Yaziv sulfur deposits of the Western region of Ukraine have been determined. The study showed that the dendroflora of post-technological areas is represented by 59 species of tree plants.Changes in the components of phytocenoses and edaphotopes are presented and the factors of transformation processes in disturbed ecosystems are analyzed. Stages of natural succession of vegetation in post-technogenic territories of lignite and sulfur deposits have been established. Physico-chemical properties of the formed embriozems were analyzed and their comparative analysis with zonal soils was carried out. It is established that the processes of vegetation restoration and soil formation in post-technogenic territories cause the gradual formation of complex plant groups and relatively stable and stable natural ecosystems.

Post-farming land restoration schemes exhibit higher soil aggregate stability and organic carbon: Evidence in the Three Gorges Reservoir Area, China

The Three Gorges Reservoir Area was dominated by a farming landscape but has been the target of restorative land management schemes over recent decades, wherein croplands have been converted to forests or citrus woodlands run by commercial enterprises or, alternatively, abandoned for natural vegetation succession. How these ongoing restorative land management schemes imprint soil systems remains poorly understood. Accordingly, in this study, a space-for-time substitution approach was applied to compare soil aggregate stability and organic carbon stocks between lands used for ongoing arable production and areas subjected to restorative practices. Composite soil samples from reforestation woodlands, abandoned croplands, citrus woodlands, and present-day croplands were collected, and a variety of soil metrics (i.e., water-stable aggregate percentage, mean weight diameter, geometric mean diameter, erosion resistance of the aggregates, bulk soil organic carbon and aggregate-specific soil organic carbon) were used as a basis for comparison. Reforestation woodlands and abandoned croplands exhibited a higher mass percentage of macro-aggregates, higher values of mean weight diameter and geometric mean diameter, and higher organic carbon content within the sampled 0–40 cm depth soil profiles. Reforestation and cropland abandonment significantly increased the stability of soil aggregates and organic carbon stocks. Moreover, abandoned cropland samples exhibited higher soil aggregate stability and organic carbon stocks than reforestation woodlands. In contrast, soil aggregate stability for all sampled soil depths and organic carbon content except for the topsoil (0–10 cm) of citrus woodlands exhibited lower values than those for present day croplands. Exclusion of crop farming and reestablishment of restorative vegetation have therefore contributed to changes in soil physical structure and organic carbon stocks, with reforestation and cropland abandonment being more beneficial for soil aggregate stability and soil organic carbon stocks in the Three Gorges Reservoir Area.

Mechanisms of vegetation restoration at landslides caused by a catastrophic earthquake in Central Taiwan

The vegetation restoration of a large-scale landslide, triggered by the catastrophic earthquake on 21 September 1999, in Jiujiu Peaks, Central Taiwan with an impacted area of 821 ha recovered 80% by 2020 was studied using self-organizing map (SOM) coupled with multi-temporal SPOT satellite images and a terrain-based distribution index for a 20-year period. Although disturbed by several typhoons during two decades of natural vegetation succession, the landslide restoration rate has reached 87.5% with the invasion or regrowth of vegetation gradually. A predicted logarithmic model with statistically significant difference was derived to estimate the restoration trend of the landslide in the studied area. Most of the poorly vegetated areas are located along the ridgelines, as verified by field surveys. Landslide restoration was carried out in three stages, (1) vulnerable landslides and fast-growing invasive vegetation (1999/9 - 2005/9); (2) stabilized landslides and slow-growing vegetation toward the vegetated strips (2005/9 - 2009/11); and (3) more stabilized landslides and vegetation toward secondary forest (2009/11–2020/2). Topographic location, water supply, typhoon disturbance, invasive or residual vegetation patterns and succession time are the main factors of landslide restoration. The evaluated results indicate that nature itself is a complex ecological balance system with a strong capacity for vegetation recovery at landslides, and can be used by government agencies to add in the recovery of landslide areas.

Slow development of woodland vegetation and bird communities during 33 years of passive rewilding in open farmland.

Passive rewilding is a potential tool for expanding woodland cover and restoring biodiversity by abandoning land management and allowing natural vegetation succession to occur. Land can be abandoned to passive rewilding deliberately or due to socio-economic change. Despite abandonment being a major driver of land use change, few have studied the long-term outcomes for vegetation and biodiversity in Western Europe. Studies are also biased towards sites that are close to seed sources and favourable to woodland colonisation. In this case-study, we reconstruct a time series of passive rewilding over 33 years on 25 ha of former farmland that had been subject to soil tipping, far from woodland seed sources. Natural colonisation by shrubs and trees was surveyed at three points during the time series, using field mapping and lidar. Breeding birds were surveyed at three time points, and compared with surveys from nearby farmland. Results showed that natural colonisation of woody vegetation was slow, with open grassland dominating the old fields for two decades, and small wetlands developing spontaneously. After 33 years, thorny shrub thickets covered 53% of the site and former hedgerows became subsumed or degraded, but trees remained scarce. However, the resulting habitat mosaic of shrubland, grassland and wetland supported a locally distinctive bird community. Farmland bird species declined as passive rewilding progressed, but this was countered by relatively more wetland birds and an increase in woodland birds, particularly songbirds, compared to nearby farmland. Alongside biodiversity benefits, shrubland establishment by passive rewilding could potentially provide ecosystem services via abundant blossom resources for pollinators, and recreation and berry-gathering opportunities for people. Although closed-canopy woodland remained a distant prospect even after 33 years, the habitat mosaic arising from passive rewilding could be considered a valuable outcome, which could contribute to nature recovery and provision of ecosystem services.

Functional Diversity and CO2 Emission Characteristics of Soil Bacteria during the Succession of Halophyte Vegetation in the Yellow River Delta.

Carbon dioxide (CO2) is the most important greenhouse gas in the atmosphere, which is mainly derived from microbial respiration in soil. Soil bacteria are an important part of the soil ecosystem and play an important role in the process of plant growth, mineralization, and decomposition of organic matter. In this paper, we discuss a laboratory incubation experiment that we conducted to investigate the CO2 emissions and the underlying bacterial communities under the natural succession of halophyte vegetation in the Yellow River Delta by using high-throughput sequencing technology and PICRUSt functional prediction. The results showed that the bacterial abundance and diversity increased significantly along with the succession of halophyte vegetation. Metabolic function is the dominant function of soil bacteria in the study area. With the succession of halophyte vegetation, the rate of CO2 emissions gradually increased, and were significantly higher in soil covered with vegetation than that of the bare land without vegetation coverage. These results helped to better understand the relationships of soil bacterial communities under the background of halophyte vegetation succession, which can help to make efficient strategies to mitigate CO2 emissions and enhance carbon sequestration.

Knowledge about Plant Coexistence during Vegetation Succession for Forest Management on the Loess Plateau, China

Coexistence between species within plant communities is a key issue in the practice of revegetation, forest management, and biodiversity conservation. Vegetation restoration is critical to control soil erosion and improve the ecological environment on the Loess Plateau. Here, we investigate the interspecific relationships of dominant plants during natural vegetation succession on the Loess Plateau. The results suggest that, under the ecological process of environmental filtering, species within communities can reduce interspecific competition and promote species coexistence via spatial heterogeneity and temporal asynchronous differences. The ecological niche overlap index (Oik) significantly and positively correlated with the strength of interspecific associations. Most species pairs had weak competition and more stable interspecific relationships. The results of the χ2 test showed that 317 species pairs were positively associated and 118 were negatively associated. The community is in a positive succession process, and the interaction relationship between species tends to be neutral. We should enhance the protection of positively associated species and pay attention to negatively associated species during forest management. Results revealed that Carex lanceolata Boott and Lespedeza bicolor Turcz coexisted easily with other species for mutual benefit, which could help build artificial forestland of native species to improve the ecological function.

Responses of edaphic factors and microbial community to terrestrial succession and experimental warming in coastal salt marshes

To date, how the combined effects of terrestrial succession and climate warming will affect the edaphic factors and microbial community of coastal salt marshes remains unclear. To address this question, we compared the growth traits (i.e., morphology and biomass), edaphic properties, microbial community and function of Phragmites australis and Imperata cylindrica communities under natural vegetation succession (i.e., shift from P. australis to I. cylindrica) with or without warming treatment of I. cylindrica over two growing seasons (2019–2020). The results showed that after terrestrial succession, soil water content (SWC), electrical conductivity, clay content, total organic carbon and total nitrogen decreased significantly, while soil pH and contents of nitrate (NO3--N) and ammonium (NH4+-N) increased. The microbial community structure was greatly altered by terrestrial succession. The combination of terrestrial succession and experimental warming reinforced the change trends of SWC and pH but caused NO3--N and NH4+-N to decline to levels as low as those before succession. Although little response in microbial community structure was detected, the relative abundances of some dominant microorganisms and functional groups involved in C and N cycling were altered under the combination treatment. These variations in dominant microorganisms and predicted functional groups were related to changes in SWC, pH and particle size fractions and further influenced soil aeration and C/N availability. We concluded that in coastal salt marshes, experimental warming could further alter soil edaphic factors after terrestrial succession with little effect on microbial community structure. The changes in microbial community composition and function had a close correlation with edaphic factors. Our results suggested that adaptive soil management practices (i.e., inoculation of important microorganisms) should be considered to mitigate the soil degradation of coastal salt marshes with terrestrial succession under predicted climate warming.

Effects of land use and cover change (LUCC) on terrestrial carbon stocks in China between 2000 and 2018

The land-use and cover change (LUCC) is a major factor in the terrestrial carbon cycle. However, the changes of vegetation biomass and soil carbon sequestration caused by land-use conversion have large uncertainties. In the study, we determined the LUCC features through the method of performing transition matrix and transfer trajectory analysis during 2000–2018. By integrating the 3-PGS model and an empirical bookkeeping model, we also explored the carbon budget from land-use conversion in the terrestrial ecosystem of China. The results demonstrated significant losses in grassland (36.22 × 106 ha), farmland (1.39 × 106 ha), and large expansion of built-up land (9.46 × 106 ha), woodland (3.59 × 106 ha). The study revealed that LUCC was driven by natural factors (11.05%) and human activities (8.25%), and natural factors, such as climate, natural vegetation succession, and other natural disturbances, were slightly higher. The total carbon storage caused by LUCC has been increased by approximately 1.32 Pg C, which stored in vegetation biomass (1.11 Pg C) and soil (0.21 Pg C), respectively. Large carbon losses (approximately 29.81 Tg C/yr) have resulted from deforestation, whereas carbon gains happened with the Grain to Green activity, cultivation, and afforestation. Overall, LUCC has a significant effect on increasing sinks in the terrestrial carbon pool in China. Our findings have implications for improving the estimation accuracy of carbon pools and comprehending the impact of human activities on regional carbon balance in China's terrestrial ecosystem.

The coupling interaction of soil organic carbon stock and water storage after vegetation restoration on the Loess Plateau, China

Vegetation restoration may increase the soil organic carbon stock (SOCS) but decrease the soil water storage (SWS) of terrestrial ecosystems in arid and semiarid regions. To guarantee the sustainability of restoration, it is critical to evaluate the coupling interaction of SOCS and SWS. Here, we examined the spatial distributions of SOCS and SWS across a 0–200 cm soil profile in a grassland, forestland and shrubland on the Loess Plateau and determined the driving factors that affected their variations. Our results showed that SOCS and SWS varied across the 0–200 cm soil profile and considerably accumulated in the deep soil layers (100–200 cm). In comparison to SOCS, SWS generally had higher relative benefits in most studied plant communities, which ensured sustainable restoration. In addition, land use played a less important role than local environmental conditions in determining the variations in SOCS and SWS. Specifically, the interaction between SOCS and SWS was mainly strong in the surface soil layers (0–20 cm). Topography was a predominant factor that affected SOCS and SWS in the deep soil layers (100–200 cm), while soil texture was a stable driving factor influencing their variations across the whole soil profile (0–200 cm). Given the low moisture consumption of grasslands and the lowest root mean square deviation (RMSD) of Hippophae rhamnoides, we proposed an advanced scenario for ecological restoration on the Loess Plateau: establishing reasonably large Hippophae rhamnoides patches with fewer edges in a contiguous grassland matrix. Furthermore, this scenario should be tailored to local environmental conditions, such as soil water, texture and topography, followed by natural vegetation succession.

Community density of grassland effect on soil carbon dynamics: Field survey and analyses from a 45‐year natural recovery time‐sequence on the Loess Plateau, China

AbstractCommunity density of grassland has obvious impacts on the absorption, sequestration, and accumulation of soil carbon (C). However, few studies have examined the effect of community density on soil C dynamics and their internal driving forces after cropland abandonment. Here, we synthesized the responses of soil C to community density of grassland over a 45‐year time‐sequence along a natural restoration time sequence. The results showed that the soil C content during the late‐successional period was greater than that during the early‐successional period, that is, annual C storage rates for the first sequence (1–15 years) for the 0–60 cm depth profiles were −0.34, −0.27, −0.15 to 0.02 Mg‐C ha−1 yr−1, in the ≤10, 11–20, 21–30, and >30 community densities. And the third sequence (31–45 years) presented values that were 79.28% and 44.60% greater than those of the initial stage of vegetation restoration (CK) for the 0–20 and 0–60 cm profiles, respectively. The increased soil C storage rates of the late‐successional sequence were associated with both increased aboveground production and root biomass for this sequence and the presence of multiple species, especially Leguminosae and Gramineae species, with developed roots. Overall, the effects of community density on soil C were regulated by the recovery time, root mass, and species genera. Furthermore, our results suggest that soil may still be a carbon source even after 15 years of the abandonment restoring, and high community density may greatly increase C capture and storage rates in abandoned lands. The findings enhance the understanding of soil C sequestration and accumulation responses to community density following long‐term natural vegetation succession, providing support for estimating and predicting the regional C budget and global C cycle.

Long-term woodland restoration on lowland farmland through passive rewilding.

Natural succession of vegetation on abandoned farmland provides opportunities for passive rewilding to re-establish native woodlands, but in Western Europe the patterns and outcomes of vegetation colonisation are poorly known. We combine time series of field surveys and remote sensing (lidar and photogrammetry) to study woodland development on two farmland fields in England over 24 and 59 years respectively: the New Wilderness (2.1 ha) abandoned in 1996, and the Old Wilderness (3.9 ha) abandoned in 1961, both adjacent to ancient woodland. Woody vegetation colonisation of the New Wilderness was rapid, with 86% vegetation cover averaging 2.9 m tall after 23 years post-abandonment. The Old Wilderness had 100% woody cover averaging 13.1 m tall after 53 years, with an overstorey tree-canopy (≥ 8 m tall) covering 91%. By this stage, the structural characteristics of the Old Wilderness were approaching those of neighbouring ancient woodlands. The woody species composition of both Wildernesses differed from ancient woodland, being dominated by animal-dispersed pedunculate oak Quercus robur and berry-bearing shrubs. Tree colonisation was spatially clustered, with wind-dispersed common ash Fraxinus excelsior mostly occurring near seed sources in adjacent woodland and hedgerows, and clusters of oaks probably resulting from acorn hoarding by birds and rodents. After 24 years the density of live trees in the New Wilderness was 132/ha (57% oak), with 390/ha (52% oak) in the Old Wilderness after 59 years; deadwood accounted for 8% of tree stems in the former and 14% in the latter. Passive rewilding of these ‘Wilderness’ sites shows that closed-canopy woodland readily re-established on abandoned farmland close to existing woodland, it was resilient to the presence of herbivores and variable weather, and approached the height structure of older woods within approximately 50 years. This study provides valuable long-term reference data in temperate Europe, helping to inform predictions of the potential outcomes of widespread abandonment of agricultural land in this region.

Population changes in the declining Turnstone (Arenaria interpres) and other waders in the northern Baltic Sea based on past and current breeding observations

Many waders are declining based on winter surveys, but assumed trends need to be validated against changes in breeding numbers. Comparing breeding population changes between threatened and non-threatened closely related species allows assessment of the species-specificity of threats. To identify biogeographical and biological correlates of population trends in declining Ruddy Turnstones (Arenaria interpres) and four other waders in the Archipelago Sea, SW Finland, we re-censused 209 islets in 2015–2018 hosting breeding Turnstones in the late 1980s–early 1990s. We used island-specific geographical variables and pair numbers of five gull and three tern species as predictors in species-specific logistic regression models of breeding probability. The number of islands with Turnstones (29) decreased by 86.1%. The proportion of islands with breeding Ringed Plovers (Charadrius hiaticula) significantly increased, while there were no trends for Redshanks (Tringa tetanus), Oystercatchers (Haematopus ostralegus) or Common Sandpipers (Actitis hypoleucos). However, the proportion of islands with more than one breeding pair of Oystercatchers increased. Ruddy Turnstone breeding occurrence was positively associated with Arctic (Sterna paradisaea) and Caspian Tern (Hydroprogne caspia) breeding numbers, island exposure and area, and negatively associated with forest area and Common Tern (S. hirundo) breeding numbers. Probable reasons for the decline are the presence of American mink (Neovison vison), a significantly declining proportion of islands with breeding Arctic Terns and natural vegetation succession. Our study highlights that population trends vary greatly between waders, but confirms the population decline of the Turnstone, now increasingly confined to exposed thinly scattered islands. Maintaining viable populations of small larids is crucial in improving its conservation status

Identification of the important environmental factors influencing natural vegetation succession following cropland abandonment on the Loess Plateau, China.

Identification of typical vegetation succession types and their important influencing factors is an important prerequisite to implement differential vegetation and soil management after land abandonment on the Loess Plateau, China. However, there is no reported study specifically on the identification of vegetation types and their important factors as well as the thresholds of the important factors for classification of the vegetation types, based on the medium- to long-term succession of natural vegetation after cropland abandonment. We collected vegetation and soil data on the natural vegetation with the longest 60-year-old forest communities that developed after cropland abandonment and analyzed the data using two-way indicator species analysis, detrended correspondence analysis, direct canonical correspondence analysis and classification tree model. The vegetation communities were classified into five distinct vegetation types, including Artemisia scoparia, Lespedeza davurica and Stipa bungeana, Artemisia giraldii pamp, Sophora viciifolia, Quercus liaotungensis and Biota orientalis. The years after cropland abandonment and soil C/N were further identified as important factors determining the types of vegetation. Likewise, it was observed that most of the investigated soil nutrient variables and soil texture-related variables improved with the vegetation succession while soil water in the surface layers showed a decreasing trend. These findings may provide an ecological basis for site-specific management of vegetation types after cropland abandonment in the medium-long term on the Loess Plateau. Our results encourage further exploration of vegetation succession and their important factors based on longer periods of vegetation succession after cropland abandonment under more soil and climatic conditions on the mountainous areas as the Loess Plateau.

Conversion of cropland to natural vegetation boosts microbial and enzyme activities in soil

The trends of enzyme activities and litter chemistry after abandonment of arable soil and succession of natural vegetation were studied in a deciduous forest zone (Moscow region, Russia). The Luvic Phaeozem chronosequence included an arable field, 3 fields with increasing abandonment periods (7, 11, 35 years), and the soil under natural forest as a reference site (never used for cropland). The activities of four hydrolytic enzymes (β-glucosidase, cellobiohydrolase, β-galactosidase, chitinase) in the topsoil (0–5 cm) were compared with chemical functional groups of plant litter identified by 13C NMR spectra. The total enzyme activity increased 5-fold during 35 years of postagricultural restoration of arable soil. The share of C-cycle enzymes with “narrower” substrate specificity (cellobiohydrolase and chitinase) increased during 35 years from 19% to 42% of the total enzyme pool. We explain this gain by the increase in the diversity and recalcitrance of organic compounds in the plant litter from cropland to natural forest. Aromaticity index of plant litter built up remarkably: from 0.11 in the young abandoned land to 0.14–0.15 in the 35-year abandoned land and the reference site. The share of enzymes with a “narrower” substrate specificity correlated closely with the portions of aryl C, O-aryl C, and carbonyl C functional groups in plant litter. Accordingly, the succession of natural vegetation on abandoned cropland leads to strong diversification of the plant litter composition and a corresponding production of soil enzymes with “narrower” substrate specificity.

Impact of vegetation succession on leaf-litter-soil C:N:P stoichiometry and their intrinsic relationship in the Ziwuling Area of China\u2019s Loess Plateau

Long-term natural vegetation succession plays a substantial role in the accumulation and distribution of plant and soil C:N:P stoichiometry. However, how plant and soil C:N:P relationships or ratios change along with successional stages over a century in the severely eroded areas remain unclear. These were measured over a 100-year natural succession in five successional stages from annual grasses to climax forests. The results show that natural succession had significant effects on carbon (C), nitrogen (N) and phosphorous (P) concentrations in leaf-litter-soil and their ratios in severely eroded areas. Nitrogen concentrations and N:P ratios in leaf and litter increased from annual grasses to the shrub stage and then decreased in the late successional forest stages. Leaf P levels decreased from annual grasses to shrub stages and did not significantly change during late successional stages. Litter P concentration decreased in the early successional stages and increased during late successional stages, with no overall significant change. Soil C and N concentrations and C:N, C:P and N:P ratios increased with successional stages. Soil C and N concentrations decreased with the increasing soil depth. Both were significantly different between any successional stages and controls (cropland) in the upper 10 cm and 10–20 cm soil layers. Leaf N:P ratios may be used to indicate nutrient limitations and this study suggests that plant growth during the grass stages was limited by N, during the shrub stage, by P, and during the forest stages, by both of N and P. In addition, there were close correlations between litter and leaf C:N:P ratios, soil and litter C and N levels, and C:P and N:P ratios. These results show that long-term natural vegetation succession is effective in restoring degraded soil properties and improving soil fertility, and provide insights into C:N:P relationships of leaf, litter and soil influenced by vegetation succession stage.

Multisensory satellite observations of the expansion of the Batagaika crater and succession of vegetation in its interior from 1991 to 2018

On-site monitoring in large areas located in inaccessible regions can be difficult and costly. Thus remote sensing is an essential tool for mapping and monitoring changes in such regions. Therefore, this paper describes long-term multisensory satellite observations of the expansion of the Batagaika crater in Northern Siberia and natural succession of vegetation in its interior from 1991 to 2018. Landsat 5 TM, Landsat 7 + ETM, Landsat 8 OLI/TIRS imageries were mainly used as a data source for analyses, although Sentinel-2A imagery and DEM image from ASTER satellite were also employed for calculating a vegetation index and expansion in the crater area. The observations were conducted in years 1991–2018 and were made in a summer season. The results reveal that the crater area increased by almost three times during these 27 years and that the fastest expansion took place between 2010 and 2014 with 22.7% increment. The analysis of elevation of the crater revealed that in 2018 its maximum depth was ca 70 m and that depth was decreasing towards its north-east tail. Additionally, the satellite imagery of land surface temperature which is a driving force of crater expansion was visualized for chosen hot days within the time frame 2010–2018. The study of temporal and spatial changes in NDVI spatial distributions inside the crater revealed also a high rate of the succession of vegetation, which may reduce melting of permafrost inside the Batagaika crater and its further expansion.