Stages Of Vegetation Succession Research Articles

The impact of grazing on biodiversity and forest succession in the Brazilian dry forest region is constrained by non-equilibrium dynamics

The impacts of grazing on rangelands have historically been studied within the framework of the equilibrium model, which predicts significant impacts of grazing on ecosystems. However, in recent decades, studies have observed a non-equilibrium pattern, suggesting that abiotic factors play a primary role compared to grazing. These studies are primarily focused on rangelands, despite animal husbandry occurring in other biomes, such as seasonally dry tropical forests. Our study examines the influence of goat grazing on biodiversity and forest succession in the Brazilian dry forest (Caatinga). Considering its high interannual precipitation variability, we hypothesize a response that aligns with the non-equilibrium paradigm. We established a gradient of grazing intensity and history in areas at different stages of vegetation succession. A survey of tree - shrub and herbaceous species was conducted at each site and the biomass of both strata was quantified. Linear mixed models and Permanova were employed to assess differences in richness, composition, structure, and biomass among the areas. Our results suggest that grazing (history and intensity) and forest fallow age did not affect species richness, but only species composition. Low and high grazing intensity drive ecosystems toward similar compositions, which align with the non-equilibrium model predictions. Biomass in the herbaceous layer remained unaffected by grazing history, intensity, or forest fallow age, whereas woody biomass was influenced by grazing intensity in older forest fallows. Although trees in low-intensity grazing sites were significantly taller compared to those in other levels, overall, grazing did not disrupt the natural succession process. Older forest fallows exhibited greater diversity and higher basal area compared to new forest fallows, irrespective of grazing intensity. Our findings suggest that: a) grazing has minimal effects on biodiversity and biomass due to non-equilibrium dynamics, and b) with appropriate management, grazing can coexist with the conservation of the Caatinga.

Soil carbon emissions and influential factors across various stages of vegetation succession in vegetated concrete

After ecological restoration of high and steep slopes in the project disturbed area, soil properties, soil microorganisms, litter types and root types change with the succession of vegetation cover communities. However, the effects of different vegetation successional stages on soil respiration dynamics remain unclear. To elucidate trends and drivers of soil respiration in the context of vegetation succession, we used spatio-temporal alternative applied research. Vegetated concrete-restored slopes (VC) with predominantly herbaceous (GS), shrub (SS), and arborvitae (AS) vegetation were selected, and naturally restored slopes (NS) were used as control. SRS1000 T soil carbon flux measurement system was used to monitor soil respiration rate. The results showed that soil respiration (RS) and fractions of all four treatments showed a single-peak curve, with peaks concentrated in July and August. During the succession of vegetation from herbaceous to arborvitae on VC slopes, RS showed a decreasing trend, and GS was significantly higher than AS by 45%; Compared to NS, RS was 29.81% and 21.56% higher in GS and SS successional stages, respectively, and 27.51% lower in AS stage. RS was significantly and positively correlated with nitrate nitrogen (NO3–-N) and microbial biomass nitrogen (MBN), both of which are important factors in regulating RS under vegetation succession. A bivariate model of soil temperature and water content explains the variability of Rs better. Overall, RS was higher than NS in the transition stage and lower than NS in the equilibrium stage of the vegetation community on VC slopes, and the RS decreases gradually with the vegetation succession of artificial ecological restoration slopes.

Effect of Vegetation Restoration on Soil Humus and Aggregate Stability within the Karst Region of Southwest China

This study aims to investigate the impact of vegetation restoration on soil humus and aggregate stability within the karst region of Southwest China. This study focused on soils at five vegetation succession stages (abandoned land, grassland, shrub rangeland, shrubland, and secondary forest) in the typical karst region, and the aggregate stability was determined using wet sieving and the Le Bissonnais method. Simultaneously, the Pallo method and separation extraction were used to determine the humus composition, aiming to analyze the distribution of humus content in the soil aggregates and its effect on aggregate stability. The results revealed the following: (1) The mean weight diameter of soil aggregates significantly increased with vegetation restoration stages. Soil water-stable aggregates at each vegetation stage mainly included particles over 2 mm in size. (2) The humic acid and fulvic acid contents consistently increased with vegetation restoration, and the precipitation quotient value of the humification degree showed an increasing trend. At each vegetation restoration stage, the percentage of each humus component was, from highest to lowest, as follows: insoluble HM, fulvic acid, humic acid, clay-bound HM, and iron-bound HM. (3) Through stepwise regression analysis, humic acid content in >2 mm aggregates, fulvic acid and clay-bound HM contents in 1–2 mm aggregates, and insoluble HM content in <0.25 mm aggregates were the dominant factors affecting soil aggregate stability in the karst region. These results aim to provide novel insights for a more in-depth comprehension of the restoration and rehabilitation of vegetation within the karst region of Southwest China, thereby laying a robust foundation for scientific theories and further investigations.

The Effects of Legacy Sediment Removal and Floodplain Reconnection on Riparian Plant Communities

Stream restoration includes a number of different approaches intended to reduce sediment and nutrient export. Legacy sediment removal (LSR) and floodplain reconnection (FR) involve removing anthropogenically derived sediment accumulated in valley bottoms to reconnect incised streams to their floodplains. These projects also present an opportunity to create high-quality riparian and wetland plant communities and provide information about the early stages of wetland vegetation development and succession. We surveyed vegetation immediately after restoration at three sites and at three additional sites 1–3 years post-restoration to determine how LSR/FR affects riparian plant communities. Restoration increased the prevalence of hydrophytic herbaceous species at all sites, suggesting these projects successfully reconnected the stream to the floodplain. Pronounced decreases in woody basal area and stem density likely also influenced an increase in native and graminoid species after restoration. Only 16% of the indicator species identified for restored reaches were planted as part of the restoration, suggesting the local seed bank and other seed sources may be important for vegetation recovery and preservation of regional beta diversity. Although vegetation quality increased after restoration in reaches with initially low-quality herbaceous vegetation, vegetation quality did not improve or decreased after restoration in reaches with higher-quality vegetation before restoration. The practice of LSR/FR has the potential to improve the quality of some riparian vegetation communities, but the preservation of high-quality forested areas, even if they are atop legacy sediment terraces, should be considered, particularly if reductions in nutrient export do not offset losses in tree canopy.

Secondary vegetation succession following reforestation intensifies preferential flow by improving soil structure in the Chinese Karst region

Preferential flow benefits water storage in deep soils that contribute to hydrological sustainability under different vegetations in the Karst regions, however, how vegetation specializes preferential flow pattern by changing soil architecture remains unclear. The study investigated the variations of soil architecture and preferential flow patterns in the agricultural field, abandoned field, and young and mature woodlands that representing four vegetation succession stages during the implementation of returning cultivated land into forest in the Karst region, to explored how soil texture and structure interact to specialize preferential flow patterns under the vegetation succession, using the dye-tracing technique, the principal component analysis (PCA), and the variation partitioning analysis (VPA). The dyed soil profiles illustrated heavy preferential flow under the four vegetations. The maximum infiltration depth (Dmax), actual infiltration depth (Dactual), total dye coverage (Ctotal), and length index (LI) significantly increased following the sequence of vegetation succession stages (P < 0.05), and the preferential pathway contribution (Dpr) was the significantly lowest under the agricultural field and young woodland and the highest under the mature woodland (P < 0.05), which indicated of intensified preferential flow with ongoing vegetation succession. The preferential flow pattern index (PFP) was constructed by the Dmax, Dactual, Ctotal, Dpr, and LI after the PCA, which gradually increased (from −0.82 ± 0.69 to 1.37±0.80) during the succession, suggesting that preferential flow percolated deeper, more preferential flow was received, and preferential flow contribution increased during the succession. Soil texture (sand content, silt content, and geometric mean soil particle size) and structure (bulk density, air-filled porosity, total porosity, air-filled porosity, and ratio of air-filled and capillary porosity to total porosity) significantly correlated to the PFP (P < 0.05). The VPA revealed that soil texture and structure independently explained 9 % and 26 % variation of the PFP. This situation means although reforestation intensified preferential flow by improving soil structure, adverse impacts of improper soil texture management of could offset the intensification efficiency by reforestation. Therefore, the results benefit to meet ecological and hydrological sustainability challenges rooted by preferential flow in the Karst regions.

Patch‐burn management affects grassland butterfly communities in cattle‐grazed rangelands

Abstract Grassland butterflies are undergoing worldwide population decline due to habitat loss and degradation. Rangelands in the Southern Great Plains can provide a habitat for grassland butterflies depending on management practices. Patch‐burn grazing is a management regime that involves burning portions of grazed pastures at different times. The combination of rotational fire and grazing creates a shifting mosaic of recently burned to older burned areas and lightly grazed to heavily grazed areas. However, the impact of fire and grazing on butterfly communities is complex and the effects of different management regimes on butterfly communities are not clear. We investigated the impact of time since prescribed fire and season of fire on butterfly communities in eight cattle‐grazed pastures, each with three burn units, in northern Oklahoma. Treatments included units burned in spring 2018, summer 2018, summer 2019, and spring 2020, with three replicates of each for a total of 12 burn units. Surveys were conducted three times per year in each burn unit in 2019 and 2020 using two standardised Pollard transects. A total of 909 butterflies and 35 species were observed. Species diversity varied by time since fire and season of fire, with spring‐burned sites having the lowest species diversity and summer‐burned sites having the highest. Dominant vegetation cover and blooming forb presence differed with time since fire and season of fire. Patch‐burn grazing creates a mosaic of successional vegetation stages which can benefit different butterfly species and support the overall community. Some species such as Cercyonis pegala, Danaus plexippus, and Atrytone arogos may benefit from fire every 1–2 years, while other species such as Echinargus isola may need longer times between fire treatments. Patch‐burn grazing regimes can support butterfly communities with species that need different fire return intervals by providing a mosaic of areas with different times since fire and associated grazing intensities.

Differences of Moss Mites Communities at Different Vegetation Succession Stages in Subalpine Wetland (Jiulongchi, Fanjing Mountain), Southwest China

Fanjing Mountain, China, is a World Man and Biosphere Reserve, a World Natural Heritage Property, and a Nature Reserve in China. Mites communities have been reported from the Fanjing Mountain. Wetland moss microhabitats provide a unique habitat for mites, and our objective is to document moss mites communities in the subalpine wetlands of Fanjing Mountain (Jiulongchi), with a particular focus on trends in moss mites at different stages of vegetation succession in the wetlands, which have rarely been described, and the research will provide fundamental data for biodiversity conservation in the face of global climate change. The succession sequence from bryophyte (hygrophyte) to shrub (mesophyte or xerophyte) in the open area of Jiulongchi wetland successively includes Polytrichum commune Hedw. (PC), Eleocharis yokoscensis (Franch. et Sav.) Tang et-Cypers sp. (EY-C), Senecio faberii Hemsl (SF), and Indocalamus longiauritus Hand.-Mazz. (IL) four typical communities. In April 2016, we collected moss samples under the four typical communities mentioned above, and analyzed the difference of moss mite communities using PCA, Kruskal–Wallis nonparametric test, and ANOVA. The results showed the following: (1) A total of 9058 moss mites belonging to 49 genera in 3 orders and 69 families were captured in the four plant communities, with the moss mites Parachipteria, Fuscozetes, and Tectocepheus being the dominant taxa of moss mites in Jiulongchi wetland. The core taxa of moss mites at different successional stages were 12 genera, with IL having the largest number of exclusive taxa (20 genera). (2) The abundance of moss mites showed an overall increasing trend from PC to IL habitats, with the number of families and genera showing a pattern of IL &gt; EY-C &gt; SF &gt; PC. The diversity index SF habitat possessed the maximum value, followed by IL, both of which were significantly different from PC. (3) The results of PCA analysis of moss mites showed that the mite community composition of PC habitats differed more from SF and IL, respectively, and less from EY-C. (4) There existed differences in the ecological taxa of predatory moss mites at different successional stages, with the Poronota group dominating the ecological taxa of oribatida. The research indicated that moss mites communities in subalpine wetlands were rich in species composition, and with the succession of vegetation from hygrophyte to mesophyte or xerophyte, the moss mites group as a whole develops in a direction favorable to its diversity, and the differences in moss mites ecological taxa also demonstrated the variability and complexity of the Jiulongchi wetland environment. This research presents the distribution pattern of moss mites in different vegetation succession stages in subtropical subalpine herbaceous wetlands. The moss mites evolution trend in response to climate-change-induced plant community succession needs further investigation.

Secondary vegetation succession on the Loess Plateau altered the interaction between arbuscular mycorrhizal fungi and nitrogen-fixing bacteria

Arbuscular mycorrhizal fungi (AMF) and nitrogen-fixing bacteria (expressing the nifH gene) play an important role in maintaining plant growth and soil function, and the reconstruction and restoration of vegetation and degraded ecosystems should focus on these communities and the links between them. However, little is known about changes in these taxa and their interactions during the natural recovery of abandoned land. Here, we investigated the changes in and interactions between AMF and nifH gene-expressing bacteria in farmland (S1), grassland (S2), shrubland (S3), pioneer forests (S4), and climax forests (S5) as five typical stages of vegetation succession on the Loess Plateau, China. We found that vegetation succession significantly influenced the diversity of AMF and nifH communities. With the progression of secondary succession, the diversity of AMF increased from farmland to pioneer forest communities, and decreased in the climax vegetation, while the diversity of the nifH community first decreased and then gradually increased. The community structures of the AMF and nifH communities differed significantly between the five vegetation types. Specifically, the AMF community structure changed significantly during the later stages of succession, while the N-fixing bacteria community tended to be stable during late succession. The interactions between AMF and nifH bacteria gradually increased from the farmland to shrub stages but tended to weaken from the shrub to climax forest stages. Therefore, the relationships between microbial communities during the early and middle stages of vegetation succession following land abandonment on the Loess Plateau are mainly cooperative and mutually beneficial, while competition likely intensifies during later successional stages. Furthermore, we found that soil microbial biomass, enzyme activity, and total phosphorus content were the main drivers of microbial community changes. Overall, this study complements current understanding of the changes and interrelationships of AMF and N-fixing bacteria during vegetation succession in areas prone to soil erosion, and provides new insights into the natural recovery of degraded ecosystems as driven by soil microbial communities.

Contrasting responses of multiple insect taxa to common heathland management regimes and old-growth successional stages

Maintaining heathlands in early successional stages to sustain heather (Calluna vulgaris) is a common, large-scale management practice in Europe. However, allowing patches of long-term natural vegetation development may increase habitat heterogeneity benefitting insects, but empirical evidence is sparse. We investigated how old-growth heathland (> 30 years abandonment) affect species richness and composition of bees (Anthophila), crane flies (Tipuloidea), ground beetles (Carabidae), hoverflies (Syrphidae) and rove beetles (Staphylinidae) in relation to their hygropreference. Adult insects, vegetation and edaphic explanatory variables were collected in old-growth, managed and wet sites and compared in four lowland heathland locations in Denmark. We found 299 species including 24 nationally red-listed. Species composition differed between managed, old-growth and wet heathland for all taxa. Indicator species and richness analyses showed a predominance of xerophilic bee species in managed heathland. Old-growth heathland showed a predominance of mesophilic indicator species, and higher richness of mesophilic crane flies and of hygrophilic ground and rove beetles compared to managed heathland. Wet heathland was generally dominated by hygrophilic species. Soil moisture, bare soil and vegetation height density were important drivers explaining the contrasting responses in richness and composition between heathland types. Our results demonstrate that heathland management focusing solely on early successional vegetation stages may homogenize insect communities. We suggest that management practices should focus on improving structural vegetation heterogeneity. This can be achieved through management regimes that reset the succession and expose bare soil, but also by allowing patches of old-growth vegetation stages to develop and by conserving existing ones.

Effects of vegetation succession on soil organic carbon fractions and stability in a karst valley area, Southwest China

A series of complex organic fractions with different physical and chemical properties make up soil organic carbon (SOC), which plays a vital role in climate change and the global carbon cycle. Different SOC fractions have different stability and respond differently to vegetation succession. This research was carried out to assess the impacts of vegetation succession on SOC dynamics in the Qingmuguan karst valley area, southwest China. Soil samples were collected from four typical vegetation succession stages, including farmland, grassland, shrubland, and forest. The total SOC content and four oxidizable SOC fractions were measured. Results showed that the total SOC content and storage under farmland were highest, followed by forest and shrubland, and the grassland had the lowest total SOC content and storage. The SOC sequestration potential under different vegetation types in the study area was grassland (26.32Mg C ha-1) > shrubland (9.64Mg C ha-1). All SOC content, storage, and fractions showed a decrease with the increase of soil depth over the 0-50cm in the study area. The four SOC fractions under forest at topsoil (0-10cm) were higher than that under the other vegetation types. Compared with the other land uses, the farmland had the highest stable oxidizable SOC fractions (F3 and F4) at the 10-50-cm depth, while the shrubland had the highest active oxidizable SOC fractions (F1 and F2). In terms of the lability index of SOC, shrubland was the largest, followed by grassland and forest, and farmland was the smallest. These results provide essential information about SOC fractions and stability changes resulting from changes of vegetation types in a karst valley area of southwest China. It also supplements our understanding of soil carbon sequestration in vegetation succession.

Characteristics of soil carbon emissions and bacterial community composition in peatlands at different stages of vegetation succession

Microorganisms are important components of soil ecosystems and play an important role in material cycles. Northern peatlands are important ecosystems in middle-high latitude regions. In peatlands, different vegetation successions occur with changes in groundwater levels. The overall carbon emission of peat bogs is related to the carbon stability of the surrounding environment. Unraveling the assembly and distribution of bacterial communities at different succession stages in peatland is essential to understanding the soil nutrient cycle. In this study, we investigated the characteristics of soil carbon emissions and the composition of subsurface microorganisms under six different succession stages. The highest carbon emission was observed in mossy peatlands, and their soil enzyme activity was closely related to the aboveground vegetation cover type. The succession pattern of ground vegetation was the main driver of soil microorganisms. The abundance of the dominant Proteobacteria decreased with increasing soil depth, while the opposite trend was observed for Chloroflexi. Furthermore, the community structure of microorganisms became progressively simpler and looser as soil water content decreased. The bacterial alpha diversity was driven by soil dissolved organic carbon and Fe, and the beta diversity was driven mainly by soil water content. The bacteria presented a random distribution in a nutrient-rich soil environment and shifted to deterministic distribution with decreasing water and nutrient contents. The balance between taxonomic diversity and dispersal limitation mediates species coexistence in the soil microbiome. This study provides new insights into the soil environment at different stages of succession in peatlands.

Community assembly during vegetation succession after metal mining is driven by multiple processes with temporal variation.

The mechanisms governing community assembly is fundamental to ecological restoration and clarification of the assembly processes associated with severe disturbances (characterized by no biological legacy and serious environmental problems) is essential. However, a systematic understanding of community assembly in the context of severe anthropogenic disturbance remains lacking. Here, we explored community assembly processes after metal mining, which is considered to be a highly destructive activity to provide insight into the assembly rules associated with severe anthropogenic disturbance. Using a chronosequence approach, we selected vegetation patches representing different successional stages and collected data on eight plant functional traits from each stage. The traits were classified as establishment and regenerative traits. Based on these traits, null models were constructed to identify the processes driving assembly at various successional stages. Comparison of our observations with the null models indicated that establishment and regenerative traits converged in the primary stage of succession. As succession progressed, establishment traits shifted to neutral assembly, whereas regeneration traits alternately converged and diverged. The observed establishment traits were equal to expected values, whereas regenerative traits diverged significantly after more than 20 years of succession. Furthermore, the available Cr content was linked strongly to species' ecological strategies. In the initial stages of vegetation succession in an abandoned metal mine, the plant community was mainly affected by the available metal content and dispersal limitation. It was probably further affected by strong interspecific interaction after the environmental conditions had improved, and stochastic processes became dominant during the stage with a successional age of more than 20 years.

Soil macrofauna in areas with different successional vegetation stages after Eucalyptus grandis harvest in Brazil

The objective of this study was to evaluate the composition of soil macrofauna over different periods after the harvest of Eucalyptus grandis to understand the ecological restoration process. Data collection was carried out in each climatic season by the “Tropical Soil Biology and Fertility” Program. In general, 25,789 individuals were collected from the soil macrofauna and distributed in 26 taxonomic groups, with the Formicidae family being the most abundant. Of the individuals found, 7,418 were collected during autumn, 7,320 in summer, 5,553 in winter, and 5,498 in spring. The soil macrofauna was influenced by seasonality, with a higher density of individuals in autumn and summer. Regarding functional groups, social groups were dominant in all areas and seasons, comprising 74.50% of the total number of individuals. The detritivores group comprised 17.98% of the total individuals. Herbivores, snails, and slugs accounted for 3.98% of the total individuals. The functional groups detritivores, herbivores, and predators were more abundant in the litter, while the social groups were predominant in the soil depths of 0 to 30 cm. As the forest progressed, the richness of the macrofauna groups increased, demonstrating the influence of successional dynamics on the composition of the soil macrofauna.

Comparative Study on Flora Characteristics and Species Diversity on Dam Slopes for Sustainable Ecological Management: Cases of Eight Dams in Korea

Dams are gray infrastructure, providing various benefits such as flood control, water supply, and power generation. In order to create the next generation of infrastructure that explores how nature can act as infrastructure to meet development and ecological sustainability, artificial plantings have been attempted on dam slopes in Korea since 2000. As the planted trees are now stabilized to form a forest, it is time to study the floral characteristics and functions for effective ecological management and the safety of the dams. In this study, we investigated and analyzed flora in the slopes of eight dams in Korea. The comparative study of the whole flora in both the planted zones of the slopes of dams and left and right forests of dams revealed that the number of plant species was higher in the planted zones than in the left and right forests of the same size area. The plant family containing the greatest number of species in the slopes was Asteraceae, followed by Poaceae, Fabaceae, and Rosaceae. Currently, the community structures and families in the slopes of dams exhibit the characteristics of habitats in the initial stage of vegetation succession. Our investigation of planted species and immigration species in the slopes revealed that the latter comprised 89.9%. An average of 34.4% of species were interacting with the dam slope and the left and right forests. The species diversity index on dam slopes showed a tendency to be higher as the number of planted species increased and the period time increased. Average growth heights of planted trees were identified as 0.5–1.6 m for the shrubs layer, 3.5–4.5 m for the small trees layer, and 6.0–7.2 m for the trees layer. The heights of major trees, including Pinus densiflora, Quercus spp., Prunus sargentii, Styrax japonicus, and Cornus controversa, were similar to or higher than those of their counterparts in natural forests. As a result, dam slopes were similar to natural forests, having potential as habitats for various flora. To harmoniously maintain the ecological health and safety of water resource facilities of the slopes of dams, however, it is necessary to conduct periodic and various investigations on changes of the flora and growth of trees, and actively manage them.

Assessing vegetation community distribution characteristics and succession stages in mountainous areas hosting coming Winter Olympics Games

Assessing vegetation community distribution characteristics and succession stages in mountainous areas hosting coming Winter Olympics Games

Motorway proximity affects spatial dynamics of orthopteran assemblages in a grassland ecosystem

Abstract Major roads have become significant components of environmental change but their impacts on invertebrate assemblages are insufficiently understood, and therefore rarely considered in road‐planning and management. In the current study, we test (i) whether and how orthopteran assemblages change with distance from a motorway, and (ii) how road‐induced changes in noise level, vegetation height and microclimate affect assemblage metrics and spatial distribution of orthopteran species. In 2018, we sampled orthopterans at five distances from a motorway: 10, 25, 50, 100 and 500 m, in eight locations within homogeneous portions of a grassland habitat in Lika region, Croatia, using two sampling methods: pitfall trapping and sweep‐netting. Orthopteran abundance, species richness, true diversity and conservation value decreased at the sites closest to the motorway in the pitfall dataset, primarily due to negative responses of species with low‐frequency acoustic signals. Road‐influenced vegetation height had a stronger overall impact on orthopteran assemblages than traffic noise and/or microclimate; increased diversity and conservation value at 25 m from the motorway suggest an effect similar to early stages of vegetation succession. This study shows, for the first time, that a major road can induce changes in adjacent orthopteran assemblages, but negative impacts are confined to a narrow zone. Our results indicate that road‐induced changes in orthopteran assemblages could be more efficiently assessed using pitfall trapping than sweep‐netting. Increasing heterogeneity of roadside habitats by appropriate vegetation management could help mitigating negative road impacts on Orthoptera in the study area, while contributing to higher diversity of their assemblages.

Changes in Soil Physical and Chemical Properties during Vegetation Succession on Miyake-jima Island

The bare lands formed after volcanic eruptions provide an excellent opportunity to study the interactions between vegetation succession and soil formation. To explore the changes in soil physicochemical properties in the vegetation succession processes and the relationship between them, soil physicochemical properties of different volcanic ash accumulation on Miyake-jima Island were studied at different vegetation succession stages. The results showed that soil bulk density gradually decreased and that soil porosity, soil water content (SWC), pH, cation exchange capacity (CEC), soil total organic carbon (TOC), and total nitrogen (TN) increased significantly with vegetation succession. The physicochemical properties changes in the soil surface horizon were most obvious, and the deep soil accumulated a large amount of relatively stable soil carbon and nitrogen. The forest land formed a thicker organic matter horizon, accumulating more carbon and nitrogen than grassland, and the soil quality index (SQI) was higher than that of grassland and shrubland. In conclusion, our research indicates the significant change in soil physicochemical properties and the improvement in soil quality in the vegetation succession processes, emphasizing a significant relationship between vegetation succession and soil development in bare land.

Whither the science in wildlife management?

Whither the science in wildlife management?

Quantifying the temporal-spatial scale dependence of the driving mechanisms underlying vegetation coverage in coastal wetlands

Coastal wetland vegetation is at risk of severe degradation at multiple scales due to multiple stresses. Although numerous studies have emphasized the importance of scale dependence, few studies have quantitatively explored how temporal-spatial scales affect vegetation coverage (VC) in coastal wetlands. To identify the effect path of scale on the driving mechanisms of VC, we constructed a structural equation model (SEM) to quantify the temporal-spatial scale dependence of the driving mechanisms of VC in coastal wetlands in China at three spatial scales (national, regional and local) mainly over a 19-year period (2000–2018, including the initial, middle and later stages of vegetation succession). The results showed that at all spatial scales, natural factors were the strongest drivers of VC at the later stage of succession (14–39 a). With reduced spatial scales, soil and topography (only middle stage, 9–11 a) played more important roles at the middle and later stages, whereas human factors had the opposite effect. The common medial factors of the driving mechanisms underlying VC were topography and soil in all scale models. The across-scale model explained 21.8% and 40.4% of the elevation and pH, respectively. The temporal-spatial scale dependences of topography and soil were stronger than those of other variables. Our findings highlight that temporal-spatial scales mainly controlled the driving mechanisms underlying VC via topography and soil in coastal wetlands. This study is the first to quantitatively reveal the effect path of scale on the driving mechanisms underlying VC in coastal wetlands.

Key species selection for forest restoration after bauxite mining in the Eastern Amazon

Bauxite mining has caused serious damage on local ecosystems and landscapes in the Eastern Amazon, Brazil. Considering these issues, the objectives of this study were to determine key species and their ecological characteristics that can contribute to forest restoration after bauxite mining. Key species are those with high frequency and abundance in different stages of vegetation succession. Data were obtained from forest inventories before forest slash down to extract bauxite and later subjected to factor analysis. The Phytosociological and Socioeconomic Index (PSI) was calculated with the following variables: abundance, frequency, dominance, live aerial biomass, commercial value of wood, and non-timber forest products of each species. The data comprised 24,600 individuals distributed in 462 species, 224 genera, and 62 families. Seventeen species, selected by PSI, were the most representative to restore areas after bauxite mining in the Eastern Amazon. The families with the highest richness were Lecytidaceae, Sapotaceae, and Fabaceae, representing 64.70% of the key species. Regarding abundance, the families Lecytidaceae, Urticaceae, and Fabaceae accounted for more than 75% of the individuals belonging to the key species. The 17 selected species belonged to the following ecological groups: late secondary (10), climax (5), initial secondary (1), and pioneer (1). The ecological knowledge of the selected species is important to plan and establish forest restoration projects, since ecological processes and functions can evolve n a more rapid and effective way.