Grassland Restoration Research Articles

New grasslands promote pollination but not biological pest control in nearby arable fields in the short term

Agricultural intensification is a major threat to farmland biodiversity and associated ecosystem services. Semi-natural habitats are integral to the preservation of farmland biodiversity and ecosystem services, however, the extent in which they contribute to specific services is largely unclear. We studied predation rates of ground-dwelling predatory arthropods, and pollination success within old permanent grasslands, newly established grasslands and arable fields near and far from new grasslands. We evaluated whether grassland restoration can enhance pollination and biological control in crop fields. For this purpose, we established new grassland strips within cereal fields, which directly bordered existing permanent grasslands. We evaluated if the distance to these old and new grasslands affects the delivery of the two ecosystem services within crop fields. We found significantly higher seed numbers and seed weight in sentinel plants placed in old grasslands, new grasslands and nearby arable fields compared to distant arable fields. We also found significantly decreasing seed numbers and seed weight in sentinel plants placed in distant arable fields with increasing distance from old grasslands, while pollination success was not affected by distance in nearby arable fields. Contrary, we did not find any significant effects of new grasslands on biological control. Our study showed that 3 years after establishing grasslands arable fields benefited from the proximity of flower-rich new grasslands through increased pollination success though not regarding biological control. This indicates that, on a short term, establishing new grasslands can support beneficial arthropods in providing ecosystem services such as pollination. Predators, in contrast, might take longer to establish effective populations that denote higher predation rates. Our study provides a baseline for future long-term studies to better evaluate pollination and pest control patterns within arable fields.

Distribution Characteristics of Carbon Density in Plant–Soil System of Temperate Steppe and Temperate Desert in the Longzhong Loess Plateau

Grassland, as a key component of the carbon cycle in terrestrial ecosystems, is vital in confronting global climate change. Characterising the carbon density of grassland ecosystems in the Longzhong Loess Plateau is important for accurately assessing the contribution of grasslands to global climate change and achieving the goal of “peak carbon” and “carbon neutral”. In this study, the Longzhong Loess Plateau was used as the research object to explore changes in the plant–soil system carbon density in two grassland types by analysing the aboveground vegetation biomass carbon density, belowground vegetation biomass carbon density, 0–100 cm soil carbon density, and ecosystem carbon density of temperate steppe and temperate desert. The results showed that the vegetation biomass (standing and living, litter, and belowground biomass), soil, and ecosystem carbon densities of the temperate steppe were significantly higher than those of the temperate desert (p < 0.05). Their carbon densities were 700.51, 7612.95, and 8313.45 g·m−2, respectively. The vertical distribution of belowground biomass and soil carbon density in the temperate steppe was significantly higher than that in the temperate desert. The overall trend of belowground biomass carbon density in the temperate steppe and temperate desert showed a gradual decrease, whereas soil carbon density showed a steady increase. More than 91% and 96% of the carbon was stored in soil in the temperate steppe and temperate desert, respectively, and the belowground biomass carbon stock accounted for more than 84% of the total biomass carbon pools in both temperate steppe and temperate desert. Temperate steppe has a significant effect in improving the carbon stock of grassland ecosystems, so ecological protection and restoration of grassland should be strengthened in the future to enhance the capacity of grassland to sequester carbon and increase sinks.

Assessing the win-win situation of forage production and soil organic carbon through a short-term active restoration strategy in alpine grasslands.

Grassland degradation has seriously affected the ecological environment and human livelihood. To abate these, implementing effective management strategies to restore and improve the service functions and productivity of degraded grasslands is crucial. To evaluate the influences of restoration measures combined with different grazing intensities on short-term (1 year) grassland restoration, the changes in soil physicochemical properties, as well as plant traits under restoration measures of different grazing intensities, reseeding, and fertilization, were analyzed. Soil organic carbon (SOC) increased to varying degrees, whereas available nutrients decreased under all combined restoration measures. Reseeding, alone and in combination with fertilization, substantially increased SOC, improved grassland vegetation status, and enhanced grassland productivity. The aboveground biomass of Gramineae and the total aboveground biomass increased under the combined restoration measures of transferring livestock out of the pasture 45 days in advance, reseeding, and fertilization (T4). Redundancy analysis revealed a strong correlation between grassland vegetation characteristics, SOC, and available potassium. Considering soil and vegetation factors, the short-term results suggested that the combination measures in T4had the most marked positive impact on grassland restoration. These findings offer valuable theoretical insights for the ecological restoration of degraded grasslands in alpine regions.

Transfer seeds, hay, or soil blocks? The importance of the completeness of biological inputs to address dispersal and establishment limitations during the restoration of plant assemblages in floodplain grasslands

This study investigated different techniques of grassland restoration to overcome dispersal or establishment limitation, which are key processes influencing early‐successional plant community assembly. A fully randomized in situ experiment was set up in a former arable land in a floodplain along the Garonne river (south‐western France) to test for the effect of (1) the type and completeness of the biological input (any biological material—seed, hay, and soil—transferred to the site under restoration), (2) soil disturbance by deep tillage, and (3) their interaction on plant community dynamics for 5 years. All inputs influenced the plant community structure and composition. The effects depended on the type of the input but not necessarily in link with its completeness. High density and diversity seed mixture led to high levels of richness and relative abundance of target species like soil blocks, the input considered as the most complete. During the first year, hay transfer mostly influenced community assembly through negative litter effects. Delayed germination of several species contributed to buffer these early effects. This study supports the importance of dispersal limitation during early succession in degraded grassland ecosystems whereas soil disturbance had only subtle effects on the seed bank and standing plant community, indicating that competition and establishment limitation were of secondary importance in our study system. Our results suggest that even low‐frequency immigration events (e.g. when a few seeds are transferred within hay) can be of great importance providing that a sufficiently long time period is considered for grassland restoration.

Overgrazing on unmanaged grassland interfered with the restoration of adjacent grazing-banned grassland by affecting soil properties and microbial community.

A "grazing ban" policy has been implemented in some pastoral areas in China to fence degraded grasslands for restoration. However, fencing increased grazing pressures in unmanaged grasslands. Based on the mechanism of negative edge effect, we investigated whether overgrazing on unmanaged grassland interfered with the restoration of adjacent grazing-banned grassland by affecting soil properties and microbial community using a sample in Hulun Buir of Inner Mongolia, in order to optimize the "grazing ban" policy. Plant and soil were sampled in areas 30 m away from the fence in unmanaged grassland (UM) and in areas 30 m (adjacent to UM) and 30-60 m (not adjacent to UM) away from the fence in the grazing-banned grassland (F-30 m and F-60 m). The species richness and diversity of plant communities and the ASV number of fungal communities significantly decreased in F-30 m and UM, and the Simpson index of the bacterial community significantly decreased in F-30 m compared with F-60 m. The abundance of fungi involved in soil organic matter decomposition significantly decreased and the abundance of stress-resistant bacteria significantly increased, while the abundance of bacteria involved in litter decomposition significantly decreased in UM and F-30 m compared with F-60 m. The simplification of plant communities decreased in soil water and total organic carbon contents can explain the variations of soil microbial communities in both UM and F-30 m compared with F-60 m. The results of PLS-PM show that changes in plant community and soil microbial function guilds in UM may affect those in F-30 m by changing soil water and total organic carbon contents. These results indicate that overgrazing on unmanaged grassland interfered with the restoration of adjacent grazing-banned grassland by affecting soil properties and microbial community. The grazing-banned grasslands should be adjusted periodically in order to avoid negative edge effects.

Effects of different fertilization patterns on soil improvement and vegetation restoration of desertified grassland in northwest Liaoning Province, China

Improving soil fertility is one of the key approaches for ecological restoration of the wind-sand area in northwest Liaoning Province. Taking wind-sand area in northwest Liaoning Province as test object, we conducted a fertilization experiment with treatments of inorganic fertilizer (nitrogen, phosphorus and potassium fertilizers), organic fertilizer, combined application of organic and inorganic fertilizers, and organic fertilizer combined with a biologically organic matrix (γ-polyglutamic acid), and no fertilizer as control. We measured soil organic matter content and extractable cations concentrations, vegetation coverage, and biomass under different fertilization treatments and determine the suitable fertilization mode. The results showed that compared to the control, inorganic fertilizer rapidly increased vegetation coverage and biomass, but high levels of inorganic fertilizer (150 kg N·hm-2) led to soil acidification and Ca2+ leaching. Organic fertilizer increased soil organic matter content, exchangeable K+, Ca2+, and Mg2+ contents, as well as coverage and biomass vegetation, especially combined with γ-polyglutamic acid. Overall, the combination of low levels of inorganic fertilizer (50 kg N·hm-2) and moderate levels of organic fertilizer (30000 kg·hm-2) was the best fertilization practice for the rapid and stable restoration of grassland in wind-sand area. Moreover, the extra addition of γ-polyglutamic acid (60 kg·hm-2)could effectively improve soil fertility.

Crinum bulbispermum, a Medicinal Geophyte with Phytostabilization Properties in Metal-Enriched Mine Tailings.

Ancient grasslands are lost through transformation to agriculture, mining, and urban expansion. Land-use change leads to ecosystem degradation and a subsequent loss of biodiversity. Globally, degraded grasslands have become a priority for restoration efforts to recover lost ecosystem services. Although the ecological and social benefits of woody species and grasses are well documented, limited research has considered the use of forbs for restoration purposes despite their benefits (e.g., C sequestration and medicinal uses). The aim of this study was to determine if Crinum bulbispermum (Burm.f.) Milne-Redh. & Schweick., a medicinal geophyte, could form part of restoration initiatives to restore mine soils in grasslands of the South African Highveld. A pot experiment was conducted to assess the performance of C. bulbispermum in a random design, with three soil treatments varying in level of degradation and metal contamination. The plants were monitored for 12 months, and the morphological characters were measured monthly to assess performance and survival. Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the soil and plant tissue concentration of potentially toxic metals. The results indicated that mine tailings negatively affected the growth and development of C. bulbispermum. Although the survival rates indicated that it could survive on tailings, its below-par productivity indicated that the species is not ideal for restoration purposes unless the tailings are ameliorated with topsoil. Although there was root accumulation of metals (Co, Cd, Cu, Mo, and Zn), there was no translocation to the bulbs and leaves, which makes C. bulbispermum suitable for medicinal use even when grown on metal-enriched soil. This species may not be viable for phytoremediation but is a contender to be used in phytostabilization due to its ecological advantages and the fact that it does not accumulate or store metals. These findings underscore the importance of considering geophytes in grassland restoration strategies, expanding their ecological and societal benefits beyond conventional approaches.

Investigation into the Effects of Different Restoration Techniques on the Soil Nutrient Status in Degraded Stipa grandis Grassland

The degradation and desertification of grassland ecosystems have garnered significant attention both domestically and internationally. Grassland restoration techniques are widely considered a principal measure to promote the sustainable utilization of grasslands, with soil nutrient content being a core indicator for assessing the effectiveness of restoration in degraded grasslands. This study aims to explore the differential impacts of various grassland restoration methods on soil nutrient distribution in degraded Stipa grandis grasslands. Three major restoration methods, i.e., root cutting, enclosure, and fertilization, were applied in the study area. The soil nutrient content was measured and analyzed under the different restoration methods and at varying depths. The results revealed that under all three restoration methods and at different soil depths (0–10 cm, 10–20 cm, 20–30 cm), the organic matter, total nitrogen, total phosphorus, alkali-hydrolyzable nitrogen, alkali-hydrolyzable phosphorus, and available potassium contents were significantly higher than those in the control group (p < 0.05). Furthermore, as soil depth increased, the contents of organic matter and all nutrients gradually decreased. Specifically, regarding the contents of different nutrients, the order of organic matter, total nitrogen, total phosphorus, alkali-hydrolyzable nitrogen, and available phosphorus was as follows: fertilization > enclosure > root cutting > control, while the contents of total potassium and available potassium followed the sequence: fertilization > enclosure > control > root cutting. Additionally, based on the canonical correlation analysis (R2 = 0.88), the total phosphorus content in soil had the greatest impact on soil nutrients, while vegetation cover and plant height contributed the most to vegetation characteristics. In grassland restoration, the increase in soil total phosphorus led to higher vegetation cover and height, mildly influenced plant diversity and density, and simultaneously promoted biomass accumulation. These research findings provide a solid theoretical foundation for the application of grassland restoration techniques, contributing to the sustainable development of grassland ecosystems.

Biochar application can mitigate the negative impacts of drought in invaded experimental grasslands as shown by a functional traits approach

Climate, land-use, and invasive plants are among the important drivers of ecosystem functions through the changes in functional composition. In this study, we studied the effects of climate (drought), land-use (Biochar application), and the presence of invasive species on the productivity and performance of invaded experimental grasslands. We ran a greenhouse experiment under controlled conditions, in which we grew a combination of the three native species Silene gallica, Brassica nigra and Phalaris minor and the invasive species Avena fatua, being subjected to four different treatments: Biochar+drought, Biochar, drought, and control. We measured the productivity of native and invasive species as total biomass and root to shoot ratio (RSR) and the performance by measuring several plant functional traits (plant height, specific leaf area (SLA), leaf dry matter content (LDMC), leaf nitrogen content (Nmass), leaf carbon content (Cmass) and total chlorophyll (Chltotal) of all individuals occurring in each plot. The study showed that invasive species were more productive (higher total biomass and lower RSR) and performed better (taller plants, higher SLA, Nmass, Cmass and Chltotal and lower LDMC) than the native species under drought conditions as well as with Biochar application. Accordingly, in contrast to our expectations, the lower productivity and performance of native compared to invasive species under drought were not mitigated by Biochar application. These results provided a deeper understanding of the interplay between climate, land-use, and biological invasion, which is crucial for predicting the consequences of changes in functional composition on ecosystem functions and consequently restoration of grasslands.

Grassland productivity increase was dominated by climate in Qinghai-Tibet Plateau from 1982 to 2020

Grassland areas occupy 60% of the Qinghai-Tibetan Plateau (QTP) and play a critical role in enhancing the ecological barrier functions of the QTP. Grassland ecosystems, and net primary productivity (NPP) in general, have dramatically changed in time and space since the 1980s, with climate warming and the intensification of human activities. Current research widely believes that climate and human activities are the common driving factors of grassland ecosystem changes on the QTP. However, there is still controversy over their dominant driving factors and their contribution rates, especially during different research periods. Therefore, this study calculated the relative contributions of climate change, human activities (except LUCC) and LUCC to actual NPP (aNPP) changes during the two periods from 1982 to 2000 to 2001–2020. This study simulated three kinds of NPPs, that is, actual NPP, potential NPP, and human-appropriated NPP, using climate productivity, the light use efficiency model, and the residual method, respectively. Moreover, the study area was divided into two parts, and then the contributions of the three factors were calculated objectively. The results showed that (1) the actual NPP (aNPP) of the QTP increased dramatically from 1982 to 2000 but did not change obviously from 2001 to 2020. (2) Comprehensive evaluation showed that climate was the dominant factor for the aNPP net increase, and its contribution rate dramatically increased from 36.3% during 1982–2000 to 224.2% during 2001–2020. Human activities changed from a positive contribution (53.3%) to a negative contribution (−124.8%) to the aNPP net increase. The contribution rate of LUCC to the aNPP increase significantly decreased from 10.4% to 0.6%. Therefore, finer grassland restoration measures and government policies must be implemented to increase NPP against the background of favorable warm-wet climate conditions for increasing grassland NPP in the QTP. These results benefit the scientific management of grassland resources and ecological barrier building on the QTP.

Changes in Nutrient-Regulated Soil Microbial Communities in Soils Concomitant with Grassland Restoration in the Alpine Mining Region of the Qilian Mountains

In response to the significant ecological damage caused by unsustainable mining practices in the Qilian Mountains, ecological restoration projects have been undertaken in recent years. Analyzing the changes in soil microbial communities during the restoration process of mine meadows helps to reveal the mechanism of the restoration process in alpine mining areas. To explore the characteristics of soil microbial community distribution and their relationships with soil environmental factors during the restoration of alpine grasslands in the Qilian Mountains, we conducted surveys and analyses in two restoration levels low restoration (LR) and high restoration (HR) in the eastern Qilian Mountains, along with an undisturbed natural grassland control (NG). We found that as the degree of high-altitude mining area recovery increases, there were significant increases in vegetation cover, vegetation height, above-ground biomass, vegetation Shannon–Wiener index, soil organic carbon (SOC), soil water content (SWC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available phosphorus (AP), and available nitrogen (AN). Conversely, soil pH and electrical conductivity (EC) significantly decreased, with soil pH decreasing from 6.93 to 4.13. Restoration of high-altitude mining area grasslands significantly alters the distribution and composition of soil bacteria and fungi, while the impact on soil microbial community changes was not significant. Notably, with increasing recovery level, the dominant bacterial phyla are Acidobacteria and Proteobacteria, while the dominant fungal phyla are Ascomycota and Basidiomycota. These results indicate that changes in vegetation and soil properties both affect the composition of soil microbial communities, with soil properties having a greater influence. Soil fertility and nutrient levels emerge as the primary drivers influencing soil microbial composition communities and the degree of high-altitude mining area grassland recovery.

Restoration approach for alpine extremely degraded landscapes: testing direct seeding and mulching with grass clippings

Alpine meadows are key ecosystems that are facing increasing degradation due to climate change and anthropogenic disturbances. Despite tremendous efforts in ecological restoration and diverse communities rebuilding in alpine regions, restoration of extremely degraded alpine meadows (which have lost mattic epipedon) remains a major challenge for land managers. Here, we performed a field restoration experiment that combined seeding three grass species commonly (Elymus nutans, Poa annua, and Festuca sinensis) used in alpine meadow restoration with the application of grass clippings as mulch (bare land without mulching, 50% mulch cover, and 100% mulch cover) to ameliorate the soil surface conditions of degraded bare land. Soils covered with 50% and 100% mulching increased soil moisture, seedling density, plant cover, plant density, aboveground biomass, and belowground biomass, and reduced soil temperature during strong radiation days and insulated at night. In the three grass species seeding plots, mulching with grass clippings also improved seedling density, plant cover, plant density, and biomass. Moreover, 100% mulching had stronger restoration effect than 50% mulching. We further demonstrated that the improvement of surface microclimate in degraded alpine meadows by grass clipping mulching, that is, increasing soil moisture and regulating soil temperature, is an important reason for the success of grassland restoration. Mulching with grass clippings simulates the original mattic epipedon, improving the surface hydrothermal conditions and promoting ecological restoration facilitation. We encourage the application of locally available grass clippings after seeding as this can be an efficient, low‐cost, and sustainable approach for restoring extremely degraded high‐elevation alpine grassland ecosystems.

Quantitative Assessment of Factors Influencing the Spatiotemporal Variation in Carbon Dioxide Fluxes Simulated by Multi-Source Remote Sensing Data in Tropical Vegetation

Vegetation plays a vital role in the global carbon cycle, a function of particular significance in regulating carbon dioxide fluxes within tropical ecosystems. Therefore, it is crucial to enhance the precision of carbon dioxide flux estimates for tropical vegetation and to explore the determinants influencing carbon sequestration. In this study, Landsat series images and Sentinel-2 Multispectral Instrument satellite data were used to invert vegetation biophysical parameters, thereby improving the timeliness and resolution of state variables from the boreal ecosystem productivity simulator (BEPS). The BEPS model at a 30 m resolution was developed to accurately capture tropical vegetation carbon dioxide fluxes across Hainan Island (HN) over the preceding two decades. The impacts of climate variations and anthropogenic activities on the carbon dioxide fluxes of tropical vegetation were further quantified using quantile regression models and a land-use transfer matrix. Results indicate significant increases in both net primary productivity (NPP) and net ecosystem productivity (NEP) in HN during the period 2000–2020, by 5.81 and 4.29 g C/m2 year, respectively. Spatial trends in vegetation carbon dioxide fluxes exhibited a consistent decline from inland regions to coastal zones. Anthropogenic activities were the dominant factor in the reduced stability of coastal NPP, while the post-2005 vegetation restoration promoted the southward expansion of high NPP (>1200 g C/m2) in the central part of HN. NPP in this tropical island was more sensitive to temperature than to precipitation, with a 1 °C temperature increase resulting in 4.1 g C/m2 reduction in dry-season NPP compared to wet-season NPP. Upgrades of cropland quality and grassland restoration have improved NPP yields, and land use transfers have resulted in a 0.301 Tg C net increase in NPP. This study provides new insight into the improvement of the carbon dioxide flux model at a finer scale for tropical vegetation and highlights ecological construction as an adaptation strategy to enhance the carbon sinks of tropical vegetation under negative climate change conditions.

The zone cube model – A tool to operationalise green infrastructure prioritisation

The concept of green infrastructure (GI) offers a comprehensive approach for environmental sustainability with the network of multifunctional ecosystems providing positive ecological, economic and societal benefits. In our study, we showed a five step conceptual framework with a case study for Hungary to evaluate GI and spatially prioritise its development methods. We created a three-dimensional zone cube model to evaluate GI performance based on the three main pillars of GI (i.e. ecological condition, ecosystem services, and ecological connectivity). We designated zones for four development approaches (i.e. ecosystem preservation, enhancement, conversion, and connectivity improvement), identified target ecosystems for conversion by using multiple potential natural vegetation (MPNV) modelling, and prioritised them based on land use conflict and feasibility indicators.According to the condition assessment, 49% of Hungary’s area may be regarded as part of the actual GI network. We identified 15.4% as possible ecosystem enhancement area, 80.3% as potential ecosystem conversion region, and 1.9% as potential landscape corridor areas in addition to 5.3% of the country’s area with outstanding GI status recommended for preservation. As an illustration of how to prioritize the restoration of grasslands, we demonstrated that 3.15 million hectares would likely be suitable for grasslands, 1.96 million hectares experience one or more environmental conflicts, and 172,000 ha should receive priority because they are also Natura 2000 sites. Our framework provided a unified operational tool overarching GI performance assessment, designation, and development prioritisation applicable at the national level providing also means to quantify measurable targets to support sustainability commitments globally.

A Possible Perspective of Recultivation with Arbuscular Mycorrhiza-Inoculated Drought-Tolerant Herbaceous Plants.

Using native species for urban green space is rather important nowadays. Plant cover on soil is necessary for agronomical and architectural investments as well as conservational programs, which all need minimal maintenance and have to be cost efficient. Commercially available seed mixtures for grasslands and lawns include species that partly originated from other mesoclimatic zones, and thus they may not be able to survive in the long-term, nor will they be adventive to the local ecosystem. With a focus on climate change, the most arid part of the Pannon geographical region was selected (near Törökszentmiklós in Nagykunság, Hungarian Great Plain). The local flora has adapted effectively to the environment; therefore, many species growing there were candidates for this study. Annuals and herbaceous perennials were investigated with respect to harvestability, reproducibility, decorativity, seed production, seed morphological characters (size, mass) and germination features. The selected 20 taxa were inoculated with INOQ Agri mycorrhiza (Rhizophagus irregularis) to increase the drought tolerance and biomass of the plants. Mycorrhizal frequency was significantly different among the taxa, reflecting various responses to the symbiotic interaction and possibly various mycorrhizal dependence of the plant species examined. We did not observe significantly higher colonization rate in most cases of the samples with artificial inoculation treatment. We conclude that the degraded mowed lawn soil that we used could contain propagules of AM fungi in a sufficient amount, so in the artificial grassland restorations, the additional AM inoculation treatment is not necessary to achieve a higher AM colonization rate.

North American prairies: Myths and realities

SummaryA North American prairie is defined, and its ecology is summarized. The potential for the restoration and recreation of prairie grassland is discussed.

Changes in Competitors, Stress Tolerators, and Ruderals (CSR) Ecological Strategies after the Introduction of Shrubs and Trees in Disturbed Semiarid Steppe Grasslands in Hulunbuir, Inner Mongolia.

To reveal the changes in the life history characteristics of grassland plants due to vegetation restoration, plant species and communities were analyzed for their competitor, stress tolerator, and ruderal (CSR) ecological strategies after the introduction of woody plants in the damaged steppe grassland and were compared with those in reference sites in Hulunbuir, Inner Mongolia. As a result, it was found that the introduction of the woody plants (Corethrodeneron fruticosum, Caragana microphylla, Populus canadensis, and Pinus sylvestris var. mongolica) into the damaged land greatly increased the plant species diversity and CSR eco-functional diversity as the succession progressed. The plant strategies of the temperate typical steppe (TTS) and woodland steppe (WS) in this Asian steppe are CSR and S/SR, respectively, which means that the plants are adapted to disturbances or stress. As the restoration time elapsed in the damaged lands exhibiting (R/CR) (Corispermum hyssopifolium), the ecological strategies were predicted to change in two ways: (1) →R/CSR (Cynanchum thesioides, Astragalus laxmannii, etc.) → CSR in places (TSS) (Galium verum var. asiaticum, Saussurea japonica, etc.) where only shrubs were introduced, and (2) → S/SR (Allium mongolicum, Ulmus pumila, etc.) → S/SR in sites (WS) (Ulmus pumila, Thalictrum squarrosum, etc.) where trees and shrubs were planted simultaneously. The results mean that the driving force that causes succession in the restoration of temperate grasslands is determined by the life-form (trees/shrubs) of the introduced woody plants. This means that for the restoration of these grasslands to be successful, it is necessary to introduce woody tree species at an early stage.

Benefits of assisted gene flow diminish with latitudinal distance between populations in Chamaecrista fasciculata

In ecological restoration, seed sourcing is often among the first and most critical steps in achieving restored populations that establish and reproduce successfully, while also having the genetic capacity to adapt to future change. Many approaches have been proposed to guide seed sourcing for restoration, including a strong focus on local seed sources, the use of assisted gene flow or assisted migration, and regional admixture provenancing. The goal of this research was to evaluate these issues in the context of grassland restoration. We collected seed of Chamaecrista fasciculata, an annual native to the prairies of North America, from four locations along a latitudinal gradient. We generated inter‐ and intrapopulation crosses and grew them in two common gardens located in restored prairies in southeast Minnesota. We found that northern populations tended to flower and fruit earlier than southern populations, while hybrids generally had intermediate phenologies. There were strong fitness benefits of hybridization, particularly among the local crosses. However, the plants grown from our southernmost seed source produced few mature seed pods in the common gardens before the advent of fall frost, suggesting that translocating populations across significant latitudinal distances may be problematic. Taken together, our findings support a regional admixture provenancing approach while indicating that assisted migration and assisted gene flow across latitudinal distances of three degrees or more compromises fitness in this species.

Effectiveness and driving mechanism of ecological restoration efforts in China from 2009 to 2019

Over the past decades, China's rapid economic growth and industrialization have led to serious ecological concerns. To combat ecological degradation and promote ecosystem sustainability, China has made substantial investments in ecological restoration in recent decades. Nevertheless, a comprehensive analysis of the effectiveness and driving mechanisms of these efforts are still lacking. Therefore, this study aims to bridge this gap by employing national land-use survey data to evaluate the effectiveness and driving mechanisms of China's ecological restoration efforts during 2009-2019, with a specific focus on ecological land preservation, land use structure, and their contribution to ecosystem services. Additionally, the Geodetector model was used to detect potential influencing factors and driving mechanisms of these efforts. The results of this study revealed that: (1) Between 2009 and 2019, a total of 585,492.61 km2 of non-ecological land was successfully transformed into ecological land through various ecological restoration efforts. Most of these areas were previously unused or cultivated land. (2) Forest and grass plantations were the major ecological restoration efforts in China, accounting for 47.35% and 41.91% of the total restored ecological land, respectively. Grassland restoration clustered northwest of the Hu Line, while forest restoration concentrated mainly to the southeast. Water and wetlands restoration were mainly distributed around China's major rivers, such as the Yangtze River and Yellow River. (3) China's ecological restoration efforts contributed to a 2.53 trillion CNY yuan increase in ecosystem service value during 2009-2019, with over 65% of the increase attributed to ecosystem regulating services. (4) China's ecological restoration efforts were mainly influenced by anthropogenic factors, such as population, land use, and urbanization, while the non-linearly enhanced interaction between natural and other factors also deserves attention. China should balance urban expansion, agricultural development, and ecological preservation, aligning restoration with socioeconomic trends while establishing effective inter-regional ecological compensation mechanisms.

Effects of fertilizer levels and drought conditions on species assembly and biomass production in the restoration of a mesic temperate grassland on ex-arable land

The restoration of degraded arable land to species-rich and functional grasslands by sowing native species has been tested successfully, while studies on restoration considering land use interest and climate change challenges are underrepresented. In this five-year study, we focused on the process of restoring grassland biodiversity and biomass production under different fertilizer levels in the face of several years of under-averaged precipitation. In 2017, we sowed a species and forb-rich native seed mixture to establish a submontane Arrhenatherion grassland. We applied fertilizer treatments (0, 60, 120 kg N ha-1 y-1, combined with and without P and K fertilizing) in order to meet local farmers' demands on biomass for hay production with nature conservation goals that aim to promote a highly species-rich and functional grassland community. Our results show that sowing a high-diverse and forbs-rich mixture not only leads to a high species richness, but also to usable aboveground biomass production for animal feeding, even with below-average precipitation. However, the slight decline in species number and cover of sown forbs following the dry period in the first year after sowing indicates the sensitivity of less drought-resistant forbs. Due to the priority effects of sown species, no undesirable species have invaded the sward. The nitrogen treatments shifted the grass-forb ratio, with grasses dominating in the nitrogen enrichment treatments due to their increased competition ability, while forbs dominating in the non-nitrogen enrichment treatments. Biomass production was higher at the first cut than at the second, and non-nitrogen fertilized treatments had a lower biomass production compared to nitrogen fertilized treatments. Both grasses and forbs contributed to drought resilience related to biomass production, but forbs contributed relatively more in the first cut under moderate or no nitrogen fertilization and in the second cut only without nitrogen application. Biomass production was strongly determined by year, and thus precipitation. Under drought conditions, species-rich stands produced sufficient biomass even without nitrogen fertilization. In order to establish and maintain species and forb-rich grasslands on ex-arable land, nitrogen fertilization should be moderate at most. Six of the 44 sown species, namely Arrhenatherum elatius, Alopecurus pratensis, Dactylis glomerata, Poa pratensis, Centaurea jacea, and Trifolium pratense, contributed significantly to the biomass and could act as matrix species in climate-adapted high-diverse native seed mixtures for our study region.