Search Results (21)

Changes in land use and agricultural practices have altered the resilience of plant communities and can lead to the emergence of invasive species. One of these is the perennial grass species Bothriochloa ischaemum (L.) Kleng., whose diversity-reducing effects are known from several studies. Our exploratory questions were as follows: How does the presence of B. ischaemum affect the diversity and ratio of the species of sandy grasslands? To what extent does this diversity change depend on site characteristics? The supporting studies were carried out in five low-lying sand dune slacks and six relatively higher areas in the upper-intermediate part of the dunes and on an abandoned old field located in the Hungarian Great Plain in the Carpathian Basin. The cover of vascular plant species was recorded in all sampling sites in twelve 2 by 2 m plots, and the dataset was analysed using agglomerative cluster analyses and a non-parametric Kruskal–Wallis test. Five significantly different groups were identified, separating the vegetation types of the sides of the sand dunes, the vegetation types of the dune slack and the old field, and a Stipa borysthenica Kolkov ex Prokudin-dominated vegetation type. Our results suggest that B. ischaemum is only present as small tussocks on the drier, more exposed sides of dunes, with 3.9–24.2% average coverage; is less able to outcompete Festuca vaginata Waldst. et Kit. ex Willd. and S. borysthenica; and is only able to form large tussocks mainly in the lower dune slacks, with 45.6–79.5% average coverage. Here, in the wetter areas, it achieves high cover with a considerable accumulation of litter, and it becomes a dominant species in this association. The diversity-reducing effect of B. ischaemum on old-field grasslands depends on the age of the site and on the stability of the vegetation. Full article

Currently, the world is facing a serious agricultural water crisis, which also affects grassland areas. Alfalfa, a key perennial forage legume, consumes about 10% of China’s pastoral irrigation water. Reducing irrigation generally results in a loss of hay yield, but the effects on alfalfa quality and its relationship to water use are less clear. In this study, we explore alfalfa quality under different irrigation deficits and its relationship to water use in the Hexi Corridor of China. Alfalfa water use, quality yield (relative feeding value yield (RFV_yield) and crude protein yield (CP_yield)), and quality water use efficiency (relative feeding value water use efficiency (WUE_RFV) and crude protein water use efficiency (WUE_CP)) were measured in a field experiment. Alfalfa quality showed a negative correlation with the irrigation quota (the determination coefficient for relative feeding value was 0.375 and for crude protein was 0.289). There was a positive correlation between quality yield and irrigation quota (the determination coefficient for RFV_yield was 0.570 and for CP_yield was 0.631). The higher irrigation quota increased quality yield, which compensated for its negative effects on alfalfa quality. The mild and moderate water deficit treatments showed lower WUE_RFV than both the severe and no water deficit treatments. Moderate or mild water deficit is recommended to be used for one-year-old alfalfa treatment. No water deficit is beneficial to improve the quality water use efficiency of two-year-old alfalfa. Full article

Afforestation is regarded as a crucial approach to enhancing terrestrial carbon sinks. Nevertheless, in ecologically fragile regions, the impacts of afforestation on carbon in biomass and soil remain highly uncertain. This study employed field investigations to explore the effects of forestry ecological projects on carbon stocks in biomass and soil within the Qinghai–Tibet Plateau, and to deeply analyze its key influencing factors. The key findings are summarized as follows: (1) The total vegetation carbon stocks of arbor forests and shrub forests (ranging from 7.7 to 24.0 Mg/ha) are 1.3–6.8 times that of grasslands (ranging from 3.5 to 6.1 Mg/ha). Afforestation-induced changes in biomass carbon are primarily attributed to the increase in carbon storage within the arbor-shrub layer, while exhibiting negligible effects on herbaceous layer carbon. (2) The soil organic carbon (SOC) stocks (0–100 cm depth) of forestland, shrubland, and grassland are 39.6–64.5 Mg/ha, 40.7–100.2 Mg/ha, and 43.1–121.9 Mg/ha, respectively. There are no significant differences in SOC stocks among shrubland, forestland, and grassland at either the 10- or 25-year development stage. The SOC stocks of 40-year-old shrubland and forestland are 1.5 and 2.3 times that of grassland, respectively. (3) For 10-year-old and 25-year-old arbor and shrub afforestation, biomass carbon increased while SOC decreased, showing a trade-off. In the case of 40- year-old afforestation, both biomass carbon and SOC increased synergistically. (4) Results from the random forest analysis indicate that the understory herbaceous diversity in this region has a significant impact on biomass carbon sequestration, and that soil total nitrogen, ammonium nitrogen, and nitrate nitrogen determine SOC sequestration. (5) Partial least squares analysis further demonstrates that afforestation promotes the retention of SOC stocks by increasing soil nutrients (especially nitrogen and nitrogen availability). Afforestation in alpine and arid regions, especially 40-year shrub afforestation, holds great carbon sequestration potential. The supplementation of soil nitrogen and phosphorus can enhance the carbon sequestration of this system. Full article

Due to the differences in the green water (GW) budget patterns of different vegetation, improper vegetation restoration may not only fail to improve the ecological environment but also cause irreversible damage to ecologically vulnerable areas, especially when vegetation restoration continues to be implemented in the future, and the pressure on water scarcity increases further. However, there is a lack of standardized research on the differences in the patterns of recharge, consumption, and efficient use of GW in typical vegetation. This makes the research results vary and cannot provide direct support for water management decision-making. Therefore, in this study, 30-year-old woodlands (R. pseudoacacia and P. orientalis) and two typical grasslands (I. cylindrican and M. sativa) that are similar to each other except for species were selected in a headwater catchment in the rain-fed agricultural area. A new GW concept and assessment framework was constructed to study the GW of long-term revegetation using a combination of field experiments and model simulations during the 2019–2020 growing season. The study findings comprise the following: (1) High-efficiency green water (GW_H), low-efficiency green water (GW_L), ineffective green water (GW_I), and available green water storage (GW_A) in the four sample plots during the study period were defined, separated, and compared. (2) An analysis of GW_A variations under different water scenarios. (3) The establishment of GW_H and GW_L thresholds. (4) Strategies to reduce GW_I and optimize GW potential while maintaining soil erosion prevention measures. (5) Suggestions for vegetation restoration species based on diverse factors. This research enhances comprehension of the impact of vegetation restoration on green water dynamics in ecologically vulnerable areas such as the rain-fed agricultural zone of the Loess Plateau. Full article

Background: Rodents severely damage the ecological environment of grasslands, and rodent mounds of different ages require distinct management strategies. Understanding the age of these mounds aids in formulating targeted restoration measures, which can enhance grassland productivity and biodiversity. Current surveys of rodent mounds rely on ground exposure and mound height to determine their age, which is time-consuming and labor-intensive. Remote sensing methods can quickly and easily identify the distribution of rodent mounds. Existing remote sensing images use ground exposure and mound height for identification but do not distinguish between mounds of different ages, such as one-year-old and two-year-old mounds. According to the existing literature, rodent mounds of different ages exhibit significant differences in vegetation structure, soil background, and plant diversity. Utilizing a combination of vegetation indices and hyperspectral data to determine the age of rodent mounds aims to provide a better method for extracting rodent hazard information. This experiment investigates and analyzes the age, distribution, and vegetation characteristics of rodent mounds, including total coverage, height, biomass, and diversity indices such as Patrick, Shannon–Wiener, and Pielou. Spectral data of rodent mounds of different ages were collected using an Analytical Spectral Devices field spectrometer. Correlation analysis was conducted between vegetation characteristics and spectral vegetation indices to select key indices, including NDVI₆₇₀, NDVI₇₀₅, EVI, TCARI, Ant, and SR. Multiple stepwise regression and Random Forest (RF) inversion models were established using vegetation indices, and the most suitable model was selected through comparison. Random Forest modeling was conducted to classify plateau zokor rat mounds of different ages, using both vegetation characteristic indicators and vegetation indices for comparison. The rodent mound classification models established using vegetation characteristic indicators and vegetation indices through Random Forest could distinguish rodent mounds of different ages, with out-of-bag error rates of 36.96% and 21.74%, respectively. The model using vegetation indices performed better. Conclusions: (1) Rodent mounds play a crucial ecological role in alpine meadow ecosystems by enhancing plant diversity, biomass, and the stability and vitality of the ecosystem. (2) The vegetation indices SR and TCARI are the most influential in classifying rodent mounds. (3) Incorporating vegetation indices into Random Forest modeling facilitates a precise and robust remote sensing interpretation of rodent mound ages, which is instrumental for devising targeted restoration strategies. Full article

The European Roller Coracias garrulus has suffered greatly from breeding habitat loss due to the renovation of old farmhouses and rural buildings and changing agricultural practices that took place extensively across Europe in the last decades. As a consequence, this species experienced a significant decline, and local extinctions of breeding populations were recorded in several European countries. We investigated nest sites and nesting area selection by the Italian Roller population during the breeding period (May–August) between 2016 and 2018. We collected 711 points from field surveys and used four types of point pattern analysis to detect space-time patterns of nest site and nesting area selection. We found that: (a) the spatial distribution of selected (i.e., occupied) nest sites was significantly nonrandom (p < 0.01) for all years and months; (b) only 2.6% of the selected nest sites was located within parks or reserves; (c) there were significant (p < 0.01) latitudinal, longitudinal, and altitudinal shifts of selected nest sites between May and August; (d) the geographical barycentres of selected nest sites shifted northward by about 80 km per month from May (southernmost barycentre) to August (northernmost barycentre); (e) four main nesting areas (7886 km² in total) occurred in central and southern Italy, whose utilization by the European Rollers differed between months but not between years; (f) the detected nesting areas corresponded mainly to non-irrigated arable lands (41.22% of their extent) and natural grasslands (12.80%). Our results are useful to support conservation strategies for the breeding sites of this farmland species, which is not a regular visitor to protected areas in Italy. Full article

In semiarid regions, the deer mouse (Peromyscus maniculatus) is a major small mammal species occupying perennial grassland habitats that include old-fields, native bunchgrass–sagebrush, and some agricultural settings. We investigated population changes in deer mouse populations in perennial grasslands, both natural and old-field, from 1982 to 2003 in southern British Columbia, Canada. Hypotheses (H) predicted that P. maniculatus populations will have (H₁) multiannual fluctuations in abundance driven by population increases from extended breeding in summer and winter; (H₂) relaxed spring reorganization events in some years leading to higher overall recruitment and survival; and (H₃) interspecific competition with montane voles that causes deer mice to be lower in density when voles are higher. P. maniculatus populations in old-field and grass–sagebrush sites had clearly defined periods of high “peak” mean numbers (32–52/ha) and other times of low mean numbers (20–22/ha). Based on mean annual peak density in autumn, deer mouse populations exhibited fluctuations of 3–4 years in both habitats, but this pattern was not always present. The greater numbers of P. maniculatus in high than low years was directly related to population increases from extended breeding seasons and an increased number of lactating females, thereby supporting H₁. Spring breeding season declines occurred but were similar or less in high than low years of mean abundance and were relaxed in comparison to forest populations of deer mice in other studies. Thus, H₂ was supported for recruitment with high numbers of young-of-the-year breeding and total number of juvenile recruits but for survival was equivocal. Total summer survival was consistently higher in high than low population years but juvenile productivity in all years was poor. Mean abundance of P. maniculatus and M. montanus in old-field sites were highly correlated, and hence H₃ was not supported. This latter result is the first, to our knowledge, of P. maniculatus coexisting in a similar pattern of population fluctuations with a Microtus species in a mainland grassland habitat. Higher than average precipitation in the year preceding a peak population of deer mice may have enhanced herbaceous vegetation and contributed to population increases in both habitats. We conclude that the old-field habitat associated with this agricultural setting provides optimum habitat for P. maniculatus and facilitates multiannual population fluctuations in this species. Full article

Scientific selection of appropriate herbage planting management mode is an important guarantee to promote artificial grassland development and grassland productivity. In this study, three-year-old alfalfa (Medicago sativa L.) and bromus inermis were applied to analyze the effects of planting patterns (bromus inermis and alfalfa mixed-sowing D1, bromus inermis mono-sowing D2), nitrogen application (pure nitrogen) level (N1: 60 kg·ha⁻¹, N2: 120 kg·ha⁻¹), and water regulation (upper and lower limits of irrigation are calculated as a percentage of field capacity θ_f, W1: slight water deficit 65~85% θ_f, W2: moderate water deficit 55~85% θ_f, W3: serious water deficit 45~85% θ_f) on herbage growth and water-nitrogen use efficiency. This research applied the principal component analysis, the TOPSIS model, and the combination evaluation to evaluate each treatment. Results demonstrated that (1) the plant height, leaf area index, and yield of mixed-sowing herbage were 81.63%, 119.52%, and 111.51%, higher than the mono-sowing herbage. Increasing the amount of irrigation and nitrogen application could enhance herbage yield. The herbage yield with the W1N2 treatment was the highest. In this treatment, the mixed-sowing herbage yield was 26,050.73 kg·ha⁻¹, and the mono-sowing herbage yield was 12,186.10 kg·ha⁻¹. (2) The crude protein content of mixed-sowing herbage increased by 41.44%, higher than mono-sowing herbage, and the relative feeding value decreased by 16.34%. Increasing irrigation and nitrogen application could improve the quality of herbage. Meanwhile, the quality of herbage treated with W1N2 was the best. (3) The water use efficiency (WUE), irrigation water use efficiency (IWUE), partial factor productivity of nitrogen (PFP_N), and crude protein water use efficiency (CP_WUE) of mixed-sowing herbage were significantly higher than mono-sowing herbage. The PFP_N and the CP_WUE of herbage improved with increasing irrigation amount. Meanwhile, the WUE, the IWUE, and the CP_WUE of herbage also improved with increasing nitrogen application amount. The results showed that mixed-sowing of alfalfa and bromus inermis with slight water deficit (upper and lower limit of irrigation was 65~85% θ_f) and nitrogen application (120 kg·ha⁻¹) could have the best comprehensive production effect. At the same time, it was a planting and management mode of high yield, high quality, and high efficiency of artificial herbage in the oasis-desert interlacing area of Hexi, Gansu Province, China, and areas with similar climates. Full article

Permanent grasslands represent the main terrestrial ecosystem and serve as an important global reservoir of biodiversity, providing a wide range of benefits to humans and ecosystems. The effects of environment on permanent meadows (in our survey, they were centuries-old meadows that had not been plowed, mowed, or fertilized with manure) production have been adequately investigated in literature. However, plant species composition impact on potential feed value of first cut has still to be understood, in particular regarding different agronomic management. Our field trial was carried out in five farms, in a territory involved in the value chain of the Parmigiano Reggiano PDO (Val d’Enza, Northern Italy), over a two-year period (2017–2018). Differences in botanical composition, biomass, and Pastoral Value index (PV), which synthesizes grassland yield and nutritional parameters, were investigated in depth. The herbage dry matter (DM) yield was affected by year, farm, and their interaction factors. Its highest value across the two years was recorded in farm 5 (11.7 tons of DM ha⁻¹), which applied the highest rate of nitrogen fertilization. The botanical composition of the first cut has favored the presence of both Poaceae and ‘other species’ (each one around 40 plants per transect) compared to Fabaceae (seven plants per transect). However, higher numbers of Fabaceae plants (13 and 10) plausibly determined increases in PV in farms 3 and 5 (56.4 and 58.7, respectively). Although differences were observed among the most important nutritional parameters of grassland (crude protein, digestible and undigested neutral detergent fiber contents), suitable net energy for lactation (NE_L) values for feeding lactating cows were always recorded during the two years of survey. The present study provides a contribution of knowledge on how the botanical composition of permanent meadows may affect their potential nutritive value as fresh herbage for feeding dairy cows. Considering these results, the agronomic management should seek a level of plant biodiversity that at the same time might guarantee satisfactory yield and feed value, also in a context of climate change. Full article

Long-term phosphorus (P) accumulation in agricultural soils presents a challenge for water quality improvement. P is commonly elevated in soils managed for intensive livestock production due to repeated overapplication of slurry and fertilisers. High legacy nutrient accumulations result in poor water quality via transport pathways such as surface runoff, subsurface drainage, and soil erosion. To achieve environmental water quality targets, improved management strategies are required for targeting and reducing excess agricultural P sources. Reseeding of old swards is known to improve grassland productivity and enhance overall soil health. However, soil disturbance associated with reseeding could have positive and negative impacts on other soil functions that affect the nutrient balance (including improved microbial activity, but also increasing the potential for sediment and nutrient losses). This study investigates the impact of reseeding and inversion tillage in addressing soil surface nutrient surpluses and identifies potential trade-offs between production, environment (through soil erosion and associated sediment and nutrient losses), and soil health. At a study site in the Blackwater catchment in Northern Ireland, we collected high-resolution (35 m) gridded soil samples pre- and post-reseeding for nutrient analyses and combined this with GIS-based interpolation. We found that decreases in sub-field scale surface nutrient content (0–7.5 cm depth) occurred following tillage and reseeding, but that this was spatially variable. In addition, the magnitude of changes in nutrient content was variable between P and other sampled nutrients. LiDAR-based image differencing indicated variability in the magnitude of soil erosion and sediment loss also at sub-field scale. Information on the identified deposition and erosion zones (from LiDAR analysis) was combined with mass wasting data to determine accumulation rates and losses of nutrients in-field and confirmed some of the identified patterns in soil surface nutrient content changes post-reseeding. We conclude that while inversion tillage and reseeding are essential agricultural practices, environmental trade-offs exist through potential nutrient and sediment losses. LiDAR-based image differencing was found to be a useful tool in helping to quantify these risks. Quantifying sediment and nutrient losses as a result of inversion tillage and reseeding induced soil erosion aids in understanding potential trends in water quality statuses. Full article

Electric powerline corridors are informal green spaces that encompass large areas of land and have the potential to support biodiversity in urban and suburban landscapes. However, the extent to which these corridors provide novel habitats compared to the surrounding landscape is unclear. Biodiversity in corridors is often compared to that of “natural” habitats despite the fact that the corridors are subject to frequent vegetation management. In urban and suburban landscapes, residential yards may provide a more appropriate comparison because they are a dominant type of green space and are also characterized by frequent vegetation management. We conducted a study of the biodiversity in suburban powerline corridors in northern Illinois, USA, and compared it to the biodiversity found in nearby residential yards. Our goal was to determine whether powerline corridors added ecological value to these suburban landscapes. We included three different management styles of powerline corridors: (1) frequently mowed and kept as lawn, (2) brush mowed on a five-year cycle (“old-field”), and (3) restored and/or maintained as native prairie. We measured the species richness and composition of plants, birds, and insect pollinators in corridors and yards. The corridor management types and comparison yards differed significantly in the richness of all three taxa, with old-field and/or prairie sites having greater species richness than mown corridors and/or comparison yards. Community composition also differed by management category. While the species richness of old-field sites tended to be high, prairie sites generally had more species of conservation interest. Our study shows that both old-field- and prairie-managed powerline corridors add habitat value to Midwestern U.S. suburban landscapes by providing alternative habitat types that support many species. Nonetheless, we suggest that managers looking to specifically support native and/or grassland specialist species in this region should manage sites as prairies when possible. Full article

In recent decades, in the Polish Carpathians, agriculture has undergone major changes. Our goal was to investigate whether the former management (plowing or mowing and grazing) had an impact on the current species composition, diversity and conservation status of the vegetation of grazing areas. We carried out vegetation studies on 45 grazing sites with traditional methods of grazing (transhumant pastoralism). The survey covered both old (continuous) grasslands and grasslands on former arable land. The most widespread were Cynosurion pastures and mesic Arrhenatherion grasslands. Wet Calthion meadows occurred at more than a half of grazing sites, while nutrient-poor Nardetalia grasslands were only recorded at several grazing sites. For each grazing site, we used soil maps from the 1960s to read land use in the past. We mapped present grassland and arable land area. Compared with the 1960s, there was a significant decrease in the area of arable land and an increase in grasslands. Species diversity was greater in grazing sites where grasslands developed on former arable land. However, this diversity was associated mainly with the occurrence of common grassland species. Cynosurion pastures and wet Calthion meadows had the best conservation status, while nutrient-poor Nardetalia grasslands were the worst preserved. We concluded that the conservation status of mesic grasslands and pastures is dependent on the present diversity of land use within a grazing site, rather than the land use history 60 years ago. This is the first study of the natural, not economic, value of pasture vegetation in the Polish part of the Carpathians. Full article

High input dairy farms that are located on sandy soils in northwest Europe are predisposed to substantial nitrate leaching during a surplus of winter precipitation. Leys within integrated crop-livestock systems play an important role in soil fertility, soil C sequestration and soil N mineralization potentials. Therefore, leys are a feasible option that can be utilized to reduce local N losses to the environment, especially following maize grown for silage. We hypothesize that grass-clover leys ensure low nitrate leaching losses even when grazed intensively. The extent to which NO₃-leaching occurred across seven different pasture management systems in terms of their sward composition, cutting, grazing, fertilization and combinations thereof was investigated in integrated animal-crop grazing systems over three winter periods (2017/2018, 2018/2019 and 2019/2020). The observed grazed systems were comprised of cut-used- and grazed grass-clover swards (0, 1 and 2 years after establishment following cereals), a catch crop grazed late in the year as well as a cut-used permanent grassland for comparison. Overall, all treatments resulted in nitrate leaching losses that did not exceed the WHO-threshold (25 mg nitrate/L). The highest level of NO₃-leaching was observed in the catch crop system and the lowest in cut-used permanent grassland, with NO₃-N losses of 19.6 ± 5.3 and 2.1 ± 0.3 kg NO₃-N ha⁻¹ year⁻¹. Annual herbage yields were in the range of 0.9 to 12.4 t DM ha⁻¹ and nitrogen yields varied between 181 ± 51 and 228 ± 66 kg N ha⁻¹ during the study period. The highest herbage-N-yields were observed from the 1- and 2-year-old grass-clover leys. The highest N-field-balance was observed for the grazed leys and the lowest for the cut-used permanent grassland. However, no correlation was found between the highly positive field-N-balance and the amount of NO₃-leached. This indicates a high N carry-over from grass-clover swards to the subsequent cash crop unit instead of increasing the risk of groundwater contamination from grazed leys in integrated animal crop-systems and underlines the eco-efficiency of dairy farming based on grazed ley systems. Full article

Restoration can recover degraded ecosystems and ecosystem services. However, effects of restoration on soil nutrient accrual are difficult to predict, partly because prior land use affects rates of soil nutrient recovery. In tallgrass prairie restorations, land-use legacy effects have not yet been quantified. We investigated topsoil carbon and nitrogen accrual within seven land-use histories: (1) row crop agriculture, (2) pasture, (3) pasture converted from row crops, (4) prairie restored from row crop, (5) prairie restored from old pasture, (6) bison prairie restored from pasture and row crops, and (7) remnant prairie. Soil samples were collected in 2008 and again in 2018 at Midewin National Tallgrass Prairie in Will County, IL. Soil samples were analyzed for bulk density, root chemistry, macro- and micronutrients, and carbon. Restored prairies contained similar soil bulk densities and rates of topsoil carbon accrual compared to each other in 2018. However, restorations from row cropping accrued nitrogen more slowly than restorations from pastures. Additionally, pastures converted from crop fields exhibited fewer legacy effects than restorations converted from crop fields. This research illustrates land-use legacy effects on soil and nutrients during grassland restorations, with implications for potential restoration trajectories and their role in carbon sequestration and ecosystem functioning. Full article

The study of ecological succession to determine how plant communities re-assemble after a natural or anthropogenic disturbance has always been an important topic in ecology. The understanding of these processes forms part of the new theories of community assembly and species coexistence, and is attracting attention in a context of expanding human impacts. Specifically, new successional studies provide answers to different mechanisms of community assemblage, and aim to define the importance of deterministic or stochastic processes in the succession dynamic. Biotic limits, which depend directly on biodiversity (i.e., species competition), and abiotic filtering, which depends on the environment, become particularly important when they are exceeded, making the succession process more complicated to reach the previous disturbance stage. Plant functional traits (PFTs) are used in secondary succession studies to establish differences between abandonment stages or to compare types of vegetation or flora, and are more closely related to the functioning of plant communities. Dispersal limitation is a PFT considered an important process from a stochastic point of view because it is related to the establishing of plants. Related to it the soil seed bank plays an important role in secondary succession because it is essential for ecosystem functioning. Soil compounds and microbial community are important variables to take into account when studying any succession stage. Chronosequence is the best way to study the whole process at different time scales. Finally, our objective in this review is to show how past studies and new insights are being incorporated into the basis of classic succession. To further explore this subject we have chosen old-field recovery as an example of how a number of different plant communities, including annual and perennial grasslands and shrublands, play an important role in secondary succession. Full article