Plant Restoration Research Articles

Young woodland restoration plantings can be resilient to uncontrolled bushfires

SummaryTree planting projects are widely conducted in agricultural areas across Australia, but relatively little is known about the vulnerability of these still young plantings to bushfires. As a result of climate change, more frequent and intense bushfires are predicted to occur across the continent. Therefore, it is important to know what happens to restoration plantings when young woody plants are burnt. To this end, we present 8 years of monitoring data from the Scottsdale Reserve in Bredbo, where we followed individual tubestock from 2013 to 2022 with an uncontrolled bushfire occurring in early February 2020. We found that Eucalypt (Eucalyptus spp.), Wattle (Acacia spp.), and Prickly Box (Bursaria spinosa) seedlings planted by volunteers had high survival rates from year to year, even after fire. Non‐resprouting species including Hop Bush (Dodonaea viscosa) and Shiny Cassinia (Cassinia longifolia) had not recovered by early 2022, though these represented a much lower proportion of the planting. Our results suggest that some components of restoration plantings are resilient to burning but others are not able to produce viable seed banks, or regrow from them in this setting. Some replanting after fire may be required to maintain desired plant diversity and structure.

Tree traits are a stronger predictor of bee traits and species richness than taxonomic diversity

Abstract Functional traits help to understand biological diversity and the mechanism by which ecological communities are structured and how they respond to the environment. For example, the high tree species diversity within tropical forests can be grouped into a few functional attributes, wood density, size and dependence on animal pollination or seed dispersal. However, little is known about how these traits influence animal taxonomic and functional diversity in the forests. We carried out a vegetation census on six plots (20 × 100 m) within the National Forest of Carajás (Amazon biome) to identify forest canopy species and their functional traits. Within the same plot, we also applied three bee sampling methods (entomological nets, honey traps and scent traps). By characterizing the functional traits of trees and bees, we were able to predict bee functional diversity better than with taxonomic diversity alone via combinations of tree traits like size, wood density, dependence on pollinators and extinction risk. We found that larger trees with low wood density were negatively associated with small, eusocial tree cavity nesting bees. The richness and abundance of trees with high extinction risk was positively associated with the richness of medium‐sized solitary bees. The dominance in the community of pollinator‐dependent trees (average diameter in the basal area) was negatively associated with the richness of above‐ground and cavity nesting bees. Our findings suggest that the composition of the tree community limits the availability of nesting resources for specific groups of bees. Moreover, the presence of trees with higher extinction risk (conservation value) was associated with a greater variety of bee traits and was the only metric associated with overall bee richness. As expected, functional traits shed light on the mechanism that might drive high diversity within tropical forests. In addition, there appears to be complementarity in terms of conservation value and carbon stock potential, as areas that habour tree species with higher extinction risk and higher wood density are also those with overall greater bee and functional diversity. Finally, our study can contribute to the restoration of plant—pollinator community by providing an understanding of the vegetation community that contributes to biodiversity maintenance. Read the free Plain Language Summary for this article on the Journal blog.

Assembly Mechanism of Rhizosphere Fungi in Plant Restoration in Lead Zinc Mining Areas

Background: So far, the assembly and response mechanism of soil fungi in the ecological restoration process of lead zinc mines is still unclear. Methods: In this study, we selected three plants for the ecological restoration of abandoned lead zinc mining areas and explored the community assembly mechanism by which soil fungi assist plants in adapting to the environment during the ecological restoration process. Results: The results revealed that the mining of lead zinc mines led to a significant decrease in soil fungal diversity, whereas the planting of three plants significantly increased the diversity of rhizosphere fungi. Mining activities significantly reduced the abundance of soil Fusarium, Macroventuria, Cladosporium, and Solicocozyma and increased the abundance of soil Helvella. After three ecologically restored plants were planted, the abundances of Fusarium and Cladosporium increased significantly, whereas the abundance of Helvella decreased significantly. In addition, Capronia was significantly enriched in the rhizosphere soils of three plant species in the mining area. β diversity and fungal guild analysis revealed that mining activities had a great impact on fungal communities and guilds. The ecological restoration of plants changed the guilds of rhizosphere fungi, making them closer to those of the control sample. In addition, the endophyte guild was significantly enriched in the rhizosphere soil of three ecologically restored plants, increasing their adaptability. Conclusions: The results provide a reference for screening lead zinc mine bioremediation strains and developing fungal plant joint remediation strategies.

Soil Physicochemical Properties and Carbon Storage Reserve Distribution Characteristics of Plantation Restoration in a Coal Mining Area

The Bulianta Coal Mine is among the problematic coal mining areas in China that is still creating environmental damage, especially associated with soil destruction. Therefore, a scientific investigation was conducted to establish a scientific basis for evaluating the impact of planted forest on soil physical and chemical properties, as well as the ecological benefits following 15 years of vegetation restoration in the area. The soil physicochemical characteristics and distribution of organic carbon storage in the 0–80 cm layer soils of Pinus sylvestris forests, Prunus sibirica forests, and Hippophae rhamnoides forests restored after 5, 10, and 15 years were investigated. The immersion method was used to determine soil porosity and density followed by the determination of soil indicators, and a statistical ANOVA test was applied to examine the differential effects of different vegetation types and restoration years on soil properties. The results clearly demonstrated the following: (1) The recovery of vegetation was achieved after a period of 15 years, with the average bulk density of the 0–80 cm soil layer as follows: P. sylvestris forest (1.513 g·cm−3) > P. sibirica forest (1.272 g·cm−3) > H. rhamnoides forest (1.224 g·cm−3), and the differences among different forest types were statistically significant (p < 0.05). (2) In planted forests, soil nutrients were predominantly concentrated in the 0–20 cm layer, while soil carbon storage exhibited a decline with an increasing soil depth. (3) The soil carbon storage across the three forest types was as follows: P. sylvestris forest (45.42 t·hm−2) > P. sibirica forest (44.56 t·hm−2) > H. rhamnoides forest (41.87 t·hm−2). In summary, during the ecological vegetation restoration process in the Bulianta Core Mine, both P. sylvestris forest and P. sibirica forest exhibit superior carbon storage capacities compared to H. rhamnoides forest, as well as more effective soil improvement outcomes.

Unrevealing the water-use strategies for typical ecological restoration plants and cash crops in the Eastern Chinese Loess Plateau region

Study regionFour geomorphic types in the eastern Loess Plateau (ECLP). Study focusquantitatively study the water-use strategies of typical plants (ecological restoration plants, food crops) based on stable isotope technology. New hydrological insights for the regionSignificant spatial-temporal heterogeneity appeared in regional soil water content and stable isotopes, with more significant fluctuations in soil water isotope values appearing in the rocky mountain region. Regional tree growth (including natural and plantation forests) was mainly influenced by precipitation (35±14 %) and surface layer (0–40 cm depth) soil water (25±11 %) during April and June, whereas deep soil water gradually became the main water source (> 20 %) in autumn and winter. A. Lavandulifolia mainly uses surface soil water (> 23 %), and the proportion of deep soil water utilization has increased after September. Surface soil water (0–40 cm) was the primary water source for T. aestivum during the overwintering (> 16 %) and reviving periods (> 26 %), and Z. mays utilized the largest proportion of soil water from 0 to 20 cm depth layer during the seeding (> 60 %) and maturation stages (> 35 %). Collectively, the results of this study have important implications for sustainable vegetation protection and the optimal allocation of water resources in the arid region.

Stoichiometric and Accumulation Characteristics of Nitrogen and Phosphorus in Artificial and Natural Herbaceous Plants along Lakeshore Buffer Zone

Lakeshore buffer zones serve as transitional areas between terrestrial and aquatic ecosystems, playing a crucial role in intercepting non-point source pollutants, purifying river and lake water, and maintaining ecological system dynamics. This study focuses on the vegetation of the lakeshore buffer zone in Songhua Lake, the largest artificial lake in Northeast China. The nitrogen (N) and phosphorus (P) pollutant contents and accumulation characteristics of herbaceous plants were investigated and analyzed in different regions and with different species. The study results indicate that there were no significant differences in N and P content, N: P ratio, and average accumulation among vegetation in the near-water, middle, and far lakeshores of the buffer area. The herbaceous plants with the highest N and P content and N: P ratios were Artemisia sieversiana, Sium suave, and Artemisia sieversiana, respectively. Purus frumentum planted in the middle lakeshore accumulated the highest amounts of N and P, reaching 87.97 g plant−1 and 3.86 g plant−1, respectively. The aboveground parts of plants showed significantly higher accumulation of N and P compared to the underground parts. The average enrichment coefficient for aboveground parts and underground parts for N were 4.83 and 4.35, respectively, all exceeding 1. However, their capability to enrich P was relatively weak, with only the aboveground parts of F − 3 showing some enrichment ability. Among herbaceous plants, Artemisia sieversiana and Sium suave exhibited the strongest capability for transporting N and P from underground to aboveground. Overall, harvesting aboveground biomass for the ecological removal of N and P in the study area appears feasible. Biomass is a critical factor influencing the nutrient interception capacity of vegetation, with Purus frumentum identified as an optimal restoration plant for sustainable management practices, and Artemisia sieversiana and Sium suave have the potential for rapid remediation.

Organic Mulching Alters the Soil Microclimate, Increases Survival and Growth of Tree Seedlings in Restoration Planting

Organic Mulching Alters the Soil Microclimate, Increases Survival and Growth of Tree Seedlings in Restoration Planting

Characteristics of Phytoplankton Community Structure in Lakes of Wetlands Dominated by Different Aquatic Plants and Its Driving Factors

In wetland ecosystems, small shallow lakes are critical transition zones of land and water, which are usually dominated by aquatic plants with different growth forms. However, the differences and key influencing factors of phytoplankton communities in shallow lakes dominated by different aquatic plants are unclear. On this basis, nine surveys were conducted at five sampling sites of three lakes in Zhangye National Wetland Park from June to November in 2022, which were respectively dominated by the emergent Phragmites australis （LL）, the submerged Potamogeton perfoliatus （CL）, and the floating-leaved Nymphaea tetragona （SL）. During the study period, the three lakes showed obvious habitat differences. A total of 237 species of phytoplankton in seven phyla and 93 genera were identified in the three lakes, including 189 species, 151 species, and 147 species in the LL, CL, and SL lakes, respectively. Among them, Ulnaria acus, Scenedesmus quadricauda, Achnanthidium minutissimum, Nitzschia stagnorum, Navicula radiosa, and Gymnodinium aeruginosum were shared dominant species of all three lakes, indicating that they had strong environmental adaptability, whereas Navicula lanceolala, Encyonopsis cesatii, and Eunotia diodon and Cymbella aequalis were only dominant in the CL, LL, and SL lakes, respectively. Simultaneously, these dominant algae appeared with obviously distinct statuses of niche width, niche overlap, and interspecific correlation among the three lakes. Using principal coordinate analysis （PCoA） and permutational multivariate analysis of variance （PERMANOVA）, significant differences were found in algal community composition among the three lakes （P<0.001）. Multiple regression on （dis）similarity matrices analysis （MRM） showed that the heterogeneity of phytoplankton communities among the three lakes was positively affected by NO3--N and pH and negatively affected by dissolved oxygen （DO） and was closely positively correlated with the abundance of six dominant species, namely, S. quadricauda, U. acus, N. stagnorum, Pseudoanabaena sp., Merismopedia punctata, and A. minutissimum. These results indicate that aquatic plants with different growth types could affect the composition, structure, and stability of phytoplankton communities in the same habitat with them by shaping their habitat heterogeneity. Therefore, selecting specific growth types of aquatic plants for aquatic ecosystem restoration in wetland construction and management will be conducive to regulate the state of water habitat and phytoplankton community structure effectively.

Reintroduction by transplanting seedlings from natural regeneration: an alternative for ecological restoration?

Collecting and transplanting wild seedlings and mature plants have been used in restoration projects to reduce costs and increase conservation of local genetic material. We review the published literature on restoration projects that used transplanted seedlings and mature plants for ecological restoration. Searching the Web of Science platform using five keywords for articles published in 1945–2023 resulted in 621 articles, with only 51 (9%) of them relevant to the topic. We categorized these 51 publications by ecosystem type, the number and growth forms of species, plant survival rate, as well as the time and cost of transplantation. Forests and wetlands were the most researched ecosystems, and most articles studied tropical forests and the southeastern region of Brazil. Nearly half of the studies (44%) used trees for transplantation, and 73% focused on only one species. In wetlands, mainly aquatic herbs were transplanted (38%). Survival was highest in wetlands (lakes) and lowest in temperate and tropical forests, regardless of the number of species or growth forms. Only three articles (7%) included costs or the time frame of the process of transplantation or monitoring. Despite having few published studies, this practice has high potential for the ecological restoration of tropical and temperate forests. Seedlings and adult plants from natural regeneration can be transplanted to complement or even replace conventional methods of planting nursery seedlings and direct sowing.

Vegetation restoration changed the soil aggregate stability and aggregate carbon stabilization pathway according to δ13C signatures

Vegetation restoration can increase soil organic carbon (SOC) sequestration through the physical protection of soil aggregates. However, the soil aggregate stability and C flow pathway associated with long-term plantation restoration have not yet been fully characterized. Here, we conducted a study on Robinia pseudoacacia plantations at different recovery stages, studied the distribution and stability of aggregates, analysed the aggregate-associated organic carbon (OC) content and δ13C value, and quantified the aggregate C flow pathway. The results revealed that vegetation restoration increased the proportion of large macroaggregates (LMAs) and decreased the proportion of small macroaggregates (SMAs), with no changes observed in the proportion of microaggregates (MIAs) or silt + clay (SC) at 0–20 cm. The indices of aggregate stability, namely, the mean weight diameter (MWD), geometric mean diameter (GMD) and structural stability index (SSI), increased under vegetation restoration at 0–20 cm, with maximum values of 3.83 mm, 2.88 mm, and 2.00 %, respectively, at 35 years of age (35Y). The OC content of the LMAs increased from 10.96 to 21.64 g kg−1 and from 7.27 to 10.05 g kg−1 in the 0–20 cm and 20–40 cm layers, respectively. LMAs and SMAs had the greatest contributions to SOC accumulation in the 0–20 cm and 20–40 cm layers, respectively. The δ13C value increased with decreasing aggregate size. The C flow pathway was from macroaggregates to MIAs or SC. Compared with abandoned farmland, vegetation restoration decreased the aggregate C flow intensity in the 0–20 cm layer. The soil aggregate stability and aggregate-associated OC content decreased with increasing soil depth, but the soil δ13C value exhibited the opposite trend. Vegetation restoration regulated soil aggregate stability by influencing the fine root biomass (FRB) and SOC content. In summary, our analysis offers a valuable reference for the controlling effect of aggregation on C stability influenced by vegetation restoration.

Testing source elevation versus genotype as predictors of sugar pine performance in a post‐fire restoration planting

AbstractClimate change is motivating a reassessment of how seeds are selected for reforestation, as rapid environmental change can lead to local maladaptation in trees. Genetic association studies and past seed source climate both have the potential to help identify appropriate planting stock, but these techniques have not been compared and tested as part of an operational planting program. In this study, we combined an analysis of single nucleotide polymorphisms (SNPs) associated with environmental gradients in sugar pine (Pinus lambertiana) with an analysis of post‐fire seedling survival and growth in a restoration experiment. Our genotype–environment association (GEA) tests of 92 individuals from varying climates within CA revealed 829 SNPs (out of 300,604) with significant association with climate gradients, especially April snowpack. Of these, 323 either had annotations that suggested potential functional importance or were identified by two different methods. We then built Bayesian models of survival and growth for all seedlings in a separate post‐fire planting experiment, to test the relative predictive ability of source elevation (a common proxy for source climate) versus the proportion of seedling alleles expected to be locally advantageous based on GEA. Across three sites within the King Fire scar in Eldorado National Forest in 2017, 2018, and 2019, 1774 seedlings were planted. Of these, 206 had enough green needles in 2020 to allow sample collection, and 161 were successfully genotyped. We found that source elevation was generally better at predicting seedling performance than genotype indices, perhaps because of the limited scope of the association analysis. Seed sources from 500 to 1800 ft (152.4–548.6 m) lower in elevation, and one seed zone further south generally performed as well or better than local seed sources. This result, and those of similar previous studies, suggest that “climate matching” using past climate information for existing seed sourcing units is a reasonable starting point for finding seedlings suited to already‐altered planting site climate conditions. However, further tests with more extensive genomic and performance data may improve the utility of genotype information for seed selection.

Occurrences Status of Biota in Gochang-gun, South Korea

The Gochang-gun biotope map was used as a benchmarking model when preparing a county unit in the future, and was prepared for the purpose of constructing detailed spatial data for eco-friendly urban management and efficient management and value improvement of cultural assets. The purpose of this study is to provide data so that it is used as basic data for the distribution status of animals and plants and the systematic management of endangered wild animals. As a result of the survey of animals and plants in Gochang-gun, a total of 255 species of 88 families and 184 genera appeared. A total of eight families and 14 species of mammals appeared. A total of 32 families and 52 species of birds appeared. A total of nine and 26 species of fish appeared, and five species endemic to Korea appeared. Six and seven species of amphibians and reptiles appeared, respectively, and one species of exotic specices appeared. A total of 26 species of benthic large-scale vertebrates appeared, and three species endemic to Korea appeared. As for endangered wild creatures, two species of plants, six species of birds and three species of mammals appeared. It is judged that the data on animals and plants based on the urban ecological status map of Gochang-gun can be used as basic data for environmental policy decisions such as the management of ecosystem disturbances in Gochang-gun, the protection of endangered wild creatures, and the protection and restoration of plant and plant habitats.

A Brief Review on Neuropharmacological Evaluation of Different Phytochemicals and Medicinal Plants in The Management of Stress and Depression.

Numerous neuropsychiatric and neurodegenerative problems, such as anxiety, cerebrovascular problems, depression, seizures, Parkinson’s disease, and others. are currently dominating the scene as a result of their high-stress lifestyle. Treatment of these issues with postponed association of produced drugs will provoke serious coincidental impacts. In recent years, researchers have stood out sufficiently to be noticed in their investigation of phytochemicals as potential treatments for neurological issues. The unique phytochemicals found in various plants, such as alkaloids, steroids, terpenoids, saponins, phenolics, and flavonoids, contribute to the neuroprotective effects of nootropic flavors. Phytocompounds from restorative plants have a significant impact on maintaining the mind’s compound equilibrium by following up on the capability of receptors for the major inhibitory synapses. recovering plants, for example, Valeriana officinalis, Nardostachys jatamansi, Withania somnifera, Bacopa monniera, Ginkgo biloba and Panax ginseng have been utilized broadly in various standard frameworks of treatment considering their adaptogenic, psychotropic and neuroprotective properties. The significance of phytochemicals’ system of action and beneficial potential in relation to neuroprotective capacity and other issues is the subject of this study.

Combined Effects of Nitrogen Addition and Warming on Shrub Growth and Nutrient Uptake through Microbially Mediated Soil Fertility

Plant restoration strategies are ubiquitously employed for the purposes of soil and water conservation and ecological improvement in forest ecosystems. Despite N and temperature being acknowledged as pivotal factors affecting plant restoration outcomes, their effects on soil fertility, microbial communities, and shrub biomass remain underexplored, particularly in the loess hilly regions of China. Here, we examined the growth patterns and nutrient acquisition abilities of three shrub species, Periploca sepium, Amorpha fruticosa, and Vitex negundo, along with the attendant alterations in soil properties and microbial community composition under controlled greenhouse conditions. Specifically, we imposed three levels of N fertilization (200, 400, and 600 kg ha−1; designated as N1, N2, and N3, respectively) and temperature regimes (18–23, 25–30, and 32–37 °C; labeled T1, T2, and T3, respectively). The results indicated a significant interplay between the combination of N fertilization and temperature significantly affecting shrub growth. Optimal growth conditions, as evidenced by the highest dry biomass accumulation, were identified as N3T1 for A. fruticosa, N1T1 for P. sepium, and N2T2 for V. negundo, with these conditions differentially influencing roots, stems, and leaves. Furthermore, soil microorganisms also responded significantly to the N fertilization and temperature. However, this was largely dependent on shrub species and soil nutrients. For A. fruticosa under N3T1 conditions, Actinobacteria and Basidiomycota abundances correlated strongly with soil C, N, and P contents, while leaf N uptake significantly correlated with the structure of both bacterial and fungal communities. For P. sepium at N1T1, Acidobacteriota was dominant in response to soil N and C, while leaf C uptake and leaf and stem N uptake positively correlated with bacterial and fungal communities, respectively. For V. negundo at N2T2, Chloroflexi had the greatest abundance, responding to the greatest variation in soil N and C, while its stem N uptake was significantly related to the structure of the fungal communities. Thus, our findings underscored the intricate interplay between abiotic factors, shrub growth, soil fertility, and microbial community dynamics, providing insights into the optimization of plant restoration efforts in ecologically sensitive regions.

Combined physiological, metabolomic and response surface approaches to analyze copper stress resistance mechanisms and repair potential of Epipremnum aureum

Phytoremediation is commonly used to remediate copper (Cu) pollution in water bodies. Epipremnum aureum is often used as a restoration plant because of its rapid reproduction, high population density and high landscape value. However, neither its ability to remediate Cu-polluted water nor its mechanism of resistance to Cu stress has been fully clarified. Therefore, the present study revealed the Cu removal ability and resistance mechanism of E. aureum through physiology and metabolomics. And based on the results of this study, the response surface was applied to the application of plant growth regulator (PGR) to propose a precise restoration program. We first examined the growth physiological indices and repair of Cu in E. aureum under different Cu stress levels and found that the resistance mechanism of E. aureum to Cu was significantly initiated at 400 mg·L-1. And as the level of Cu stress increased, the Cu content in the plant also increased, and the underground part was the main accumulating part. The translocation factor of E. aureum was <1, and the bioconcentration factor was greater than 1 at all different Cu concentrations. Subsequently, metabolomics studies on E. aureum concluded that arginine and proline metabolism, indole alkaloid synthesis and brassinosteroid biosynthesis are the major pathways involved in the mechanism of Cu stress resistance in E. aureum. Based on these results, we proposed that salicylic acid, sodium nitroprusside and 2,4-epibrassinolide could be selected as PGRs, and further optimized the administration of PGRs using response surfaces. The optimized scheme allowed E. aureum to reach a maximum Cu removal of 84.39 % under 400 mg·L-1 Cu stress, which was 35.61 % higher than the non-fortified treatment. This study provides supporting materials and application options for the Cu repair capacity and resistance mechanisms of E. aureum.

Regenerating and Developing a National Botanical Garden (NBG) in Khartoum, Sudan: Effect on Urban Landscape and Environmental Sustainability

This research focuses on the National Botanic Garden in Khartoum, Sudan, proposing tools and methods to assess botanical garden quality from multiple perspectives. It explores the related concepts between national botanical gardens and landscapes, regeneration landscapes and their components such as botanical gardens, their effects on urban regeneration in cities, urban environments, and environmental sustainability. This study aims to: regenerate and develop a National Botanical Garden in the Almogran area of Khartoum, Sudan, and highlight the importance of establishing a national botanical garden for each climatic region in Sudan. The study used questionnaires to identify the necessary needs for regeneration, and the opinions of employees of the Ministry of Agriculture and Forestry were surveyed about the purposes of: (1) evaluating the garden’s total area and interior design; (2) building regeneration; (3) establishing constructions, such as a library, seed gene bank, tissue culture laboratory, etc.; (4) emphasizing the need for modern technology to enhance quality. The study summarizes five regeneration technology methods: environmental plant restoration, water body restoration, building and facility restoration, reconstruction technology, and resource utilization; (5) botanical gardens were proposed for each climatic region in Sudan, and we studied the effects of establishing a botanical garden for each climate region in Sudan on environmental resilience, the effect of the botanical gardens’ regeneration on gardens within the cities, and effect of a national botanical garden on the urban landscape and environmental sustainability. These findings suggest that the comprehensive regeneration of the National Botanical Garden, integrating it with the urban regeneration of cities, especially urban greening regeneration, is important for enhancing urban landscapes, enhancing environmental resilience, environmental sustainability, climate change, and achieving land development goals, thus helping to address actual requirements and develop sustainable cities.

Overlooked drivers of the greenhouse effect: The nutrient-methane nexus mediated by submerged macrophytes

Submerged macrophytes remediation is a commonly used technique for improving water quality and restoring habitat in aquatic ecosystems. However, the drivers of success in the submerged macrophytes assembly process and their specific impacts on methane emissions are poorly understood. Thus, we conducted a mesocosm experiment to test the growth plasticity and carbon fixation of widespread submerged macrophytes (Vallisneria natans) under different nutrient conditions. A refined dynamic chamber method was utilized to concurrently collect and quantify methane emission fluxes arising from ebullition and diffusion processes. Significant correlations were found between methane flux and variations in the physiological activities of V. nantas by the fluorescence imaging system. Our results show that exceeding tolerance thresholds of ammonia in the water significantly interfered with the photosynthetic systems in submerged leaves and the radial oxygen loss in adventitious roots. The recovery process of V. natans accelerated the consumption of dissolved oxygen, leading to increase in the populations of methanogen (153.3 % increase of mcrA genes) and subsequently elevating CH4 emission fluxes (23.7 %) under high nutrient concentrations. Conversely, V. natans increased the available organic carbon under low nutrient conditions by radial oxygen loss, further increasing CH4 emission fluxes (94.7 %). Quantitative genetic and modeling analyses revealed that plant restoration processes drive ecological niche differentiation of methanogenic and methane oxidation microorganisms, affecting methane release fluxes within the restored area. The speciation process of V. natans is incapable of simultaneously meeting improved water purification and reduced methane emissions goals.

Tropical Timber Species Grow Faster in Full Sun Than in the Understory of Restoration Plantings

Tropical Timber Species Grow Faster in Full Sun Than in the Understory of Restoration Plantings

Restoration-mediated protein substances preferentially drive underlying bauxite residue macroaggregate formation during the simulated ecological reconstruction process

Constructing a restoration strategy from bauxite residue to Technosols is a cost-effective and sustainable strategy for addressing the ecological and environmental issues caused by high alkalinity, salinity, and fine-grained bauxite residues. However, the quantitative contribution of restoration strategies on the upper bauxite residue-derived Technosols to the underlying untreated bauxite residue in the short term remains poorly understood. This study investigated the mediating mechanisms of vegetation and microbial metabolic effects on the alkalinity, nutrient content, and structure of the underlying bauxite residue (20-50 cm) through a simulated ecological reconstruction of the bauxite residue stockpile. Results indicated that implementing plant restoration strategies resulted in the content of polyphenolic compounds, lipids, tannins, and carbohydrates in bauxite residue dissolved organic matter (DOM) increased significantly from 52.5, 8.2, 3.3, and 2.0 % to 54.4, 10.4, 5.6, and 2.8 %, respectively, while the content of condensed aromatics, unsaturated hydrocarbons, and proteins/amino sugars decreased significantly from 15.5, 12.0, and 6.5 % to 12.1, 9.7, and 5.1 %, respectively. The newly produced molecules were concentrated in regions with low O/C and high H/C ratios, suggesting that short-term vegetation restoration strategies facilitate the transformation of substrate DOM towards easily decomposable and highly bioavailable substances. This led to the migration of the newly produced molecules to the underlying bauxite residue, and as a result, the protein and soluble microbial products of the underlying bauxite residue increased significantly, as well as the pH, exchangeable Na, and < 0.054 mm particles decreased from 10.2, 44.2 cmol kg−1, and 28.1 % to 9.7, 27.1 cmol kg−1, and 19.4 %, respectively, available nitrogen, urease, and 1–2 mm particles increased from 7.3 mg kg−1, 0.2 U mg−1, and 14.5 % to 7.6 mg kg−1, 0.3 U kg−1, and 21.7 %, respectively. Results of the structural equation model further confirmed that plant biomass, proteins/amino sugars, and condensed aromatics in the upper Technosol were the main factors controlling the aggregate formation of the underlying bauxite residue by mediating the protein-dominated biogenic organic matter produced by microbial metabolism.

Interpretation of Soil Characteristics and Preferential Water Flow in Different Forest Covers of Karst Areas of China

Soil hydrology seriously affects the prevention of desertification in karst areas. However, water infiltration in the different soil layers of secondary forests and artificial forests in karst areas remains uncertain. This lack of clarity is also the factor that constrains local vegetation restoration. Therefore, monitoring and simulating the priority transport of soil moisture will help us understand the shallow soil moisture transport patterns after artificial vegetation restoration in the local area, providing a reference for more scientific restoration of the ecological environment and enhancement of carbon storage in karst areas. The integration of soil physical property assessments, computed tomography (CT) scanning, dye tracing studies, and HYDRUS-2D modeling was utilized to evaluate and contrast the attributes of soil macropores and the phenomenon of preferential flow across various forestland categories. This approach allowed for a comprehensive analysis of how the soil structure and water movement are influenced by different forest ecosystems and infiltration head simulations (5 mm, 15 mm, 35 mm, and 55 mm) to elucidate the dynamics of water movement across diverse soil types within karst regions, to identify the causes of water leakage due to preferential flow in secondary forests, and to understand the mechanisms of water conservation and reduction in artificial forests adopting a multifaceted approach. This study demonstrated that (1) the soil hydrological capacity of a plantation forest was 20% higher than a natural forest, which may be promoted by the clay content and distribution. (2) Afforestation-enhanced soils in karst regions demonstrate a significant capacity to mitigate the loss of clay particles during episodes of preferential flow and then improve the soil erosion resistance by about 5 times, which can effectively control desertification in karst area. (3) The uniform distribution of macropores in plantation forest soil was conducive to prevent water leakage more effectively than the secondary forest but was incapable of hindering the occurrence of preferential flow. The secondary forest had a very developed preferential flow phenomenon, and soil clay deposition occurred with an increase in depth. (4) Moreover, the results for preferential flow showed that the matrix flow depth did not increase with the increase in water quantity. Short-term and high-intensity heavy rainfall events facilitated the occurrence of preferential flow. Infiltration along the horizontal and vertical directions occurred simultaneously. These results could facilitate a further understanding of the contribution of the plantation to soil amelioration and the prevention of desertification in karst areas, and provide some suggestions for the sustainable development of forestry in karst areas where plantation restoration is an important ingredient.