Mountain Grasslands Research Articles

Environmental assessment of mountain grassland farms with mixed cattle systems: use of bioeconomic simulations

Management practices of cattle farming systems must be improved, particularly to increase the systems’ feed self-sufficiency, food production and environmental performances. In mountain areas of the Massif Central (central France), mixed dairy/suckler cattle systems enable farmers to use grassland resources better and cope with economic fluctuations. Our objective was to estimate levels of ecosystem services provided by mixed dairy/suckler cattle systems as a function of the degree of mixing, along with their greenhouse gas emissions and energy use when their operation is optimized on an economic basis. The hypothesis was that mixed dairy/suckler cattle systems allow for controlled use of biomass, with better environmental performances than specialized systems (pure dairy or suckler herd) by maintaining grassland ecosystem services. Five herd-distribution scenarios were simulated using the Orfee bioeconomic optimization model. Environmental performances of the five systems were assessed according to three functional units (i.e., per farm, ha and kg protein produced). Mixed dairy/suckler cattle systems, which enabled larger herds, had higher greenhouse gas emissions per ha than specialized systems. However, because dairy cows produce more protein (milk and beef) than suckler cows, specialized dairy systems had the lowest greenhouse gas emissions and energy use per kg of protein. Specialized dairy systems had less advantage when dairy cows had less access to grassland. For the production of both milk and beef, mixed dairy/suckler cattle systems favour more sustainable use of biomass and tend to maintain a better combination of levels of ecosystem services for livestock production than specialized cattle farming systems.

Temporal and Spatial Variations in Carbon Flux and Their Influencing Mechanisms on the Middle Tien Shan Region Grassland Ecosystem, China

Grassland ecosystems are an important component of global terrestrial ecosystems and play a crucial role in the global carbon cycle. Therefore, it is important to study the carbon dioxide (CO2) process in the Middle Tien Shan grassland ecosystem, which can be regarded as a typical representative of the mountain grasslands in Xinjiang. Eddy covariance (EC) and the global carbon fluxes dataset (GCFD) were utilized to continuously monitor the Middle Tien Shan grassland ecosystem in Xinjiang throughout the 2018 growing season. The findings revealed notable daily and monthly fluctuations in net ecosystem exchange (NEE), gross primary productivity (GPP), and ecosystem respiration (Reco). On a daily basis, there was net absorption of CO2 during the day and net emission during the night. The grassland acted as a carbon sink from 6:00 to 18:00 and as a carbon source for the remaining hours of the day. On a monthly scale, June and July served as carbon sinks, whereas the other months acted as carbon sources. The accumulated NEE, GPP, and Reco during the growing season were −329.49 g C m−2, 779.04 g C m−2, and 449.55 g C m−2, respectively. On the half-hourly and daily scales, soil temperature (Ts) was the main contributor to CO2 fluxes and had the greatest influence on the variations in CO2 fluxes. Additionally, air temperature (Ta) showed a strong correlation with CO2 fluxes. The grassland ecosystems exhibited the strongest CO2 uptake, reaching its peak at soil temperatures of 25 °C. Moreover, as the air temperatures rose above 15 °C, there was a gradual decrease in NEE, while CO2 uptake increased. The applicability of GCFD data is good in the grassland ecosystem of the Middle Tien Shan Mountains, with correlations of 0.59, 0.81, and 0.73 for NEE, GPP, and Reco, respectively, compared to field observations. In terms of remote sensing spatial distribution, the Middle Tien Shan grassland ecosystem exhibits a carbon sink phenomenon.

Ensilibility and protein degradation characteristics of forage from mountain grasslands containing tanniferous species

AbstractEnsiling forage from species‐rich mountain grasslands is challenging. Low concentrations of fermentable carbohydrates and the coarse morphological structure of the forage promote the activity of butyric acid forming bacteria. This is associated with the formation of ammonia from protein degradation, resulting in an insufficient pH decline. On the other hand, forage from species‐rich swards may contain tanniferous plant species which contain varying contents of condensed tannins (CT). Therefore, the silage quality of forage prepared from species‐rich mountain grasslands and the role CT may play in silage fermentation was studied. A set‐up of two long‐term mineral fertilization field experiments, located in the Jura mountains and the Alps in Switzerland were used to obtain forage with contrasting species and chemical composition. Collection was done during both the generative and vegetative growth stage from three differently fertilized swards: unfertilised (“0”), fertilized with phosphorus and potassium (“PK”) or fertilized with PK and nitrogen (“NPK”). The forage was wilted to approximately 37% dry matter (DM), chopped to 2 cm lengths and ensiled for at least 65 days as laboratory‐scale silages. The wilted forage was characterized by concentrations of crude protein between 117 and 130 g/kg DM and water‐soluble carbohydrates varying from 84 to 148 g/kg DM. Concentrations of CT ranged from 6 g to 14 g/kg DM and those of soluble CT from 1.8 to 7.6 g/kg DM. All silages contained butyric acid, irrespective of the type of fertilization or harvest stage (range: 1.5 g to 16 g/kg DM). Concentrations of acetic and lactic acid ranged from 2.1 g to 15.0 g/kg DM and from 21.0 to 44.0 g/kg DM, respectively. Concentrations of unfermented sugar remained high and pH levels were above those expected. Formation of non‐protein‐N (NPN) increased in the range of 130 to 264 g/kg N from wilted to ensiled forage. The negative correlations of CT or soluble CT contents with ammonia‐N or NPN in silage were found in both forage from the generative and vegetative harvests indicating a possible relationship with protein degradation during ensiling.

Persisting effects of seed bed preparation and early grazing on plant communities in grassland restoration

Semi-natural mountain grasslands are species-rich and provide a wide range of ecosystem services, such as biomass production for livestock grazing and carbon sequestration. Land abandonment but also habitat destruction are threatening these ecosystems highlighting the need for restoration when degraded. The transfer of plant material containing seed collected at non-degraded reference sites is increasingly used for restoration but the appropriate methods to prepare the transfer and to manage the grassland afterwards are still under debates. This study aims at testing the effects of seed bed preparation by harrowing and livestock grazing on the establishment of transferred targets and community trajectories towards the reference system. In a previous study, first year seedling counts showed a positive effect of seed bed preparation and a marginally significant negative effect of grazing on the seedling recruitment of the transferred species. We asked whether the results on first year seedling densities translate into significant effects on plant cover and whether these effects on plant cover change in the following three years. Both grazing and harrowing effects on species establishment were tested using a full factorial split-plot experimental design on five replicate sites. Data on species richness and vegetation cover for both the whole plant community and the transferred species were analysed during four years after seed transfer. The cover of transferred species increased whereas their species richness remained unchanged. We found a weak positive effect of harrowing on total cover whereas grazing had no effect. Seed bed preparation by harrowing had a clear positive effect on transferred target species cover. The negative effect of grazing on first-year seedling recruitment of transferred target species turned into a positive effect in the fourth year. However, this effect was only apparent in the harrowed plots resulting in a significant grazing-by-harrowing interaction. The similarity of the plant communities to the reference increased from the first to the fourth year and this increase was stronger in grazed and harrowed plots. In conclusion, the results confirmed the positive effect of seed bed preparation on restoration by seed transfer and demonstrated that initial grazing exclusion is not needed in mountain grasslands of our study area.

Effects of Fire Frequency Regimes on Flammability and Leaf Economics of Non-Graminoid Vegetation

Fire is an ecological factor that strongly influences plant communities and functional traits. Communities respond differently to fire, either decreasing or increasing in flammability and resource acquisition strategies. This study aimed to investigate the influence of fire over traits associated with flammability and the plant economic spectrum in a stressful and infertile mountainous grassland located in the Espinhaço mountain range in Brazil. Non-graminoid plant species were sampled in 60 5 m × 5 m plots distributed in three fire frequency categories. We measured several traits related to flammability—leaf dry matter content (LDMC), twig dry matter content, leaf area, bark thickness, branching architecture, plant height, leaf toughness (LT), and specific leaf area (SLA). Traits responded differently to the increase in fire frequency. For instance, the LDMC and LT were lower while the SLA was higher at high fire frequencies, indicating a trend towards reduced heat release and fire residence time. This shift resulted in the dominance of plants with a relatively more acquisitive strategy. This study brings evidence that traits respond coordinately towards a reduction of flammability with the increase in fire frequency and are strong indicators of the filtering role that fire plays as a disturbance on rupestrian grassland vegetation.

An integrative approach supports the taxonomic distinction of the Sardo-Corsican endemic Euphorbia semiperfoliata from the widespread E. amygdaloides (Euphorbiaceae)

In the western Mediterranean, Corsica and Sardinia are characterised by high plant diversity and endemism, and exhibit a tight biogeographic connection. One of the endemic taxa thriving in forests, macchia, along riversides and in mountain grasslands of both islands is Euphorbia semiperfoliata. It was often considered a subspecies of the widespread European forest plant Euphorbia amygdaloides, or deemed closely related with the western Asian E. macroceras and E. oblongifolia. Here, we explored the evolutionary origin of E. semiperfoliata using nuclear ITS sequences that showed that E. semiperfoliata is divergent from E. amygdaloides and the other species of E. sect. Patellares, which indicates its old, likely Tertiary origin. In addition, its relative genome size is different from E. amygdaloides and other species and several morphological characters revealed by morphometric analyses differentiate E. semiperfoliata from E. amygdaloides. Finally, we provide a taxonomic treatment for E. semiperfoliata, including the typification and a morphological description.

Differences between thermal preference and thermal performance in a wintry spider Mecicobothrium thorelli: are the spiders under evolutionary pressures on their seasonal activity?

Thermal preference and thermal performance are used to describe the thermal biology of an ectothermic organism through parameters, i.e., estimating locomotor performance by maximum running speed. In this study, we assessed the thermal preference and locomotor performance of the spider Mecicobothrium thorelli Holmberg, 1882, a wintry mygalomorph spider endemic to the native mountainous grasslands of central Argentina and Uruguay. The preferred temperatures of the 72.4% of the individuals were in the range of 10–20 °C. The highest frequencies of preferred temperatures were 10–15 °C in males and 15–20 °C in females. The sprint speed showed significant differences between all the temperatures evaluated and showed the highest speeds at 25 °C and the lowest at 3 °C. The optimal temperature was 26.09 °C, which was significantly higher than the preferred temperature in both males and females. We concluded that M. thorelli selects a wide range of temperatures and prefers to stay in medium and low temperatures, which are correlated with winter activity in the wild. However, the species showed maximum speed at higher temperatures, which implies that spiders would perform even better in nature and maximize their locomotion by being active during a warmer period.

Shepherds View of Large Carnivore Recovery in the Pyrenees, Spain.

The studied farms are small family businesses, and so, in more than half of the cases, their continuity is not guaranteed. Livestock management is typical of a mountain system, in which the animals graze throughout the year in cultivated fields, sown meadows, forests near the farms, and mountain pastures during the three summer months. The herds always have the constant surveillance of a shepherd. Farmers consider the current infrastructure present in mountain grasslands insufficient to facilitate the management and care of their herd. Their activity conflicts with various species of wildlife, such as the wild boar, Sus scrofa, roe deer, Capreolus capreolus, or griffon vulture, Gyps fulvus, and large carnivores such as the brown bear, Ursus arctos, or the grey wolf Canis lupus, despite all of them taking preventive measures to defend their herds from predators. The most widely used prevention measures are the presence of mastiff dogs, Canis lupus familiaris, next to the herds and the use of electric fencing to lock up livestock at night. Farmers reject the presence of bears and wolves in their area, considering it a real threat to the continuity of their economic activity, which presents a high degree of vulnerability.

Indirect interactions between pollinators drive interaction rewiring through space

AbstractIn recent years, an extended body of literature has focused on the importance of either temporal or spatial dynamics in shaping the structure of interacting plant and pollinator communities. This improvement from a previously static and aggregated perspective has allowed us to understand many of the ecological processes that shape community assembly. However, fewer are the studies that have simultaneously focused on spatial and temporal dynamics, and even fewer are those that collect data across different habitat types to assess the generality of their findings. Here, we used a dataset collected weekly throughout the full flowering season for two consecutive years and within two contrasting habitat types in N and SW Spain: a mountain grassland area and the understory of sparse pine forests. We evaluated species and interaction persistence through space and time, pollinator fidelity, and turnover patterns in interaction composition while providing a potential mechanistic explanation for the patterns observed. Our results show that although species generalization does not explain species or interaction persistence, moderately generalist species are those showing the greatest fidelity to the subset of plant species they visit through space and time. Further, we find that interaction turnover through time is mostly driven by changes in species composition, while through space it is mostly driven by interaction rewiring resulting from indirect competitive interactions between pollinator species. Our results help to shed light on the potential mechanisms driving community assembly patterns beyond niche or neutral processes by adding within‐trophic‐level interactions that can modify pollinator preferences.

Cover Picture and Issue Information

Journal of EcologyVolume 111, Issue 6 p. 1167-1169 COVER PICTURE AND ISSUE INFORMATIONFree Access Cover Picture and Issue Information First published: 07 June 2023 https://doi.org/10.1111/1365-2745.13917AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Graphical Abstract Cover image: A ‘deeper look’ into species-rich mountain grassland in the Krkonoše Mountains, Czech Republic. The grassland is dominated by a narrow-leaved grass, Festuca rubra. Microbial and abiotic soil legacies induced by this dominant can be altered by other co-occurring plant species. Photograph by Eliška Kuťáková. For full details see pages 1203–1217. Volume111, Issue6June 2023Pages 1167-1169 RelatedInformation

Remote sensing as a tool of biological conservation and grassland monitoring in mountain areas of Southeastern Kazakhstan

Grassland degradation, as a worldwide phenomenon, has economic and bio-conservation aspects. Degradation of mountain grasslands severely impacts the stability of ecosystems in fragile mountain environments and may destroy the habitats of many endemic and endangered species. One of the significant triggers of mountain grassland degradation, along with the possible consequences of climate change, is massive overgrazing. Overgrazing may seriously influence the ecosystem since it results in plant composition changes, soil erosion, water regime disturbances, etc., up to the disappearance of the entire ecosystem. It is crucial to have a reliable and cost-effective instrument for the ecosystem assessment of remote and hardly accessible mountain areas supported by accurate methods of vegetation parameter estimation since the vegetation cover is first to react to externally driven disturbances. The current study was conducted in the Dzungarian Alatau Mountains, inhabited by the rare and endemic anuran amphibian Ranodon sibiricus (Kessler, 1886). The project of the Conservation International Foundation (CIF/326/21) was aimed at the strategy of species conservation. The current study emphasises estimating the overgrazing risks for the amphibian population. More than two hundred ground measurements were done within the Upper Koksu Forestry and adjacent areas to provide representative data on the vegetation parameters. We tested a series of spectral indices related to vegetation biophysical parameters. We found the DWSI, GrNDVI, IRECI and NDI45 indices to provide the best correlations and reasonable accuracy for remote measurements of above-ground biomass, grass cover, and unpalatable grass content. Sentinel-2 data with the red-edge bands, in most cases, provided better performance. Our study confirmed that the use of a single criterion (like above-ground biomass) might result in a serious underestimation of grassland degradation. Data obtained from field surveys and satellite information analysis allowed the evaluation of the optimal grazing load for the Upper Koksu Forestry and provided recommendations for the Action Plan on the Conservation of Ranodon sibiricus.

The influence of fire presence and absence on grass species composition and species richness at Mountain Zebra National Park

It is well known that fire is a common driver in many biomes and it plays a vital role in maintaining ecosystem functioning in many South African biomes. This ecosystem process is an important determinant of plant community composition and diversity, and can result in changes in structural composition and ecosystem functioning. The main objectives of this study are to determine the influence of fire on grass species richness, diversity and composition in Mountain Zebra National Park. Using satellite imagery, the park’s fire history was determined between 2000 and 2020. Eighty plots (approximately 20 m × 20 m; 100 m apart) were laid out purposively across different fire regimes. There was no significant difference in both species richness and diversity in burned and unburned sites. However, there was a difference in species composition between burned and unburned sites and between different fire frequencies. The unburned site had higher moribund material and unpalatable grasses compared to the burned area.Conservation implications: The results of this study will help in the completion of the fire management plan for the park which will enable conservation managers to make better decisions with regard to fire management in mountainous grassland at Mountain Zebra National Park. Consequently, this will lead to improved veld condition and vegetation structure.

Contrasting patterns along tall grass dominance in mowed mountain grasslands

Semi-natural grasslands are a perfect system to study how biotic interactions influence coexistence thanks to their high species diversity in small areas resulting from millennia of anthropogenic management. Management cessation led to the increase of highly competitive tall-perennial tussock species with a marked drop of taxonomical (TD) and functional diversity (FD). The effect of highly competitive tall-perennial tussock species on plant community under management condition is largely understudied. In this study, we try to shed light on the effect of Brachypodium genuense which dominates sub-Mediterranean abandoned mountain grasslands TD and FD. For FD, we selected as traits plant height (H), specific leaf area (SLA) and leaf area (LA). We hypothesized i) TD decreases as the cover of B. genuense increases; ii): H converges towards higher values resulting from weaker competitive exclusion; iii) SLA and LA diverge resulting from limiting similarity. TD and FD were calculated using Rao's Quadratic Entropy. We computed the community weighted mean (CWM) that we analysed with fourth corner approach and built linear models using B. genuense as a predictor. We found that B. genuense ability in dominating the grassland plant community is altered by mowing in two different ways. On one hand, increase of B. genuense lead to a drop in TD whereas for FD the increase showed contrasting patterns with divergence for H and convergence for SLA. On the other, there were changes in the main dominant strategies with an overall increase in mean trait values of both H and SLA indicating species taller in size and more fast-growing. Overall, our results highlighted how tall-perennial tussock species under mowing conditions lead to a more stratified plant community convergent towards resource acquisition strategies. A multifaceted approach should be adopted to have a better understanding of the biotic drivers on different aspect of plant community.

Remote sensing as a tool of biological conservation and grassland monitoring in mountain areas of Southeastern Kazakhstan

Grassland degradation, as a worldwide phenomenon, has economic and bio-conservation aspects. Degradation of mountain grasslands severely impacts the ecosystem stability in fragile mountain environments and may destroy habitats of many endemic and endangered species. One of the significant triggers of mountain grassland degradation, along with possible consequences of climate change, is massive overgrazing. Overgrazing may seriously influence the ecosystem since it results in plant composition changes, soil erosion, water regime disturbances, etc., up to the disappearance of the entire ecosystem. It is crucial to have a reliable and cost-effective instrument for the ecosystem assessment of remote and hardly accessible mountain areas supported with accurate methods of the vegetation parameters estimation since the vegetation cover is first to react to externally driven disturbances. The current study was conducted in Dzungarian Alatau Mountains, inhabited by the rare and endemic anuran amphibian Ranodon sibiricus, Kessler, 1886. The project of the Conservation International Foundation (CIF/326/21) was aimed at the strategy of this species conservation. The current study emphasises estimating the overgrazing risks for the amphibian population. More than two hundred ground measurements were done within the Upper Koksu Forestry and adjacent areas to provide representative data on the vegetation parameters. We tested a series of spectral indices related to vegetation biophysical parameters. We found DWSI, GrNDVI, IRECI and NDI45 indices to provide the best correlations and reasonable accuracy for remote measurements of above-ground biomass, grasscover and unpalatable grass content. Sentinel-2 data with the red-edge bands, in most cases, provided better performance. Our study confirmed the use of a single criterion (like above-ground biomass) might result in a serious underestimation of grassland degradation. Data obtained from field survey and satellite information analysis allowed the evaluation of the optimal grazing load for the Upper Koksu Forestry and provided recommendations for the Action Plan on the conservation of Ranodon sibiricus.

Plant–soil feedbacks in a diverse grassland: Soil remembers, but not too much

Abstract Plant–soil feedbacks (PSFs) are one of the major drivers of species coexistence in highly dynamic and low‐diversity communities, such as early successional stands or agricultural systems. However, in stable and species‐rich communities, PSFs are much more complex because of numerous species interactions. In this study, we aimed to reveal if PSFs of a dominant species can be detected within a diverse plant community and to what extent they can be influenced by the effects of co‐occurring species. We investigated PSFs between a dominant grass, Festuca rubra, and three other species from a species‐rich mountain grassland, taking advantage of the 18‐year field removal experiment. We tested whether such a long‐term presence/absence of Festuca can shape the feedback of the grassland community and whether these effects prevail in the lower soil layer, where Festuca roots are relatively more abundant, compared to the upper soil layer. We evaluated how experimentally induced soil legacies of Festuca in a pot experiment are modified by subsequently grown plants, both at the level of plant responses and changes in abiotic and biotic soil properties. At the level of the entire community, the soil legacies of the dominant Festuca were not detectable. However, the responses of the plants differed between the soil samples from the upper and lower soil layer. The pot experiment showed that the soil legacies of subsequently growing plants interact, influencing soil properties as well as plant responses to these altered soils. Generally, we found a stronger signal of the most recent conditioning, although the effect of the first conditioning plant was still detectable in many of the measured variables. Plant biomass in the feedback phase was mainly linked to the levels of plant‐available soil nitrogen, although it was also affected by the composition of microbial communities. Synthesis. We showed that plant‐induced soil legacies can be altered by legacies of co‐occurring species, complicating plant–soil feedbacks in diverse communities. Despite the detectable legacy effects on final plant biomass, in the short term, plant growth responds more strongly to the levels of available nutrients. We also highlight the vertical distribution of plant–soil feedbacks.

An Erosion-Based Approach Using Multi-Source Remote Sensing Imagery for Grassland Restoration Patterns in a Plateau Mountainous Region, SW China

Satellite remote sensing of grassland ecosystem restoration requires considering both the above-ground biomass and soil information, and the latter is even more crucial due to the value and restoration difficulty of soil productivity. In this study, we proposed an approach to support the restoration pattern for mountainous grasslands at regional scale. The approach integrates different aspects and key processes, including degradation status, restoration potential and recovery capability, compared to a reference state. Specifically, we illustrated the method with the case of grasslands in southwestern China from a conservation perspective. Soil erosion conditions, net primary productivity and regrowth rate of grasslands were selected as indicators to reveal restoration possibilities. The results showed that the method proposed for remote sensing identification of grassland distribution has an overall accuracy of 88.21% at the regional scale. 59.54% of grasslands in Zhaotong are being eroded with an unsustainable erosion rate greater than the tolerant soil loss, and the average annual soil erosion rate is 952.17 t/(km2·a). Meanwhile, there is obvious spatial heterogeneity in soil erosion factors, vegetation restoration potential and regrowth rate, and the dry–hot valley of Jinsha River in the southwest is much more sensitive to climate change and vulnerable than other regions. The grassland vegetation cover revealed a fluctuating trend and protection of grassland vegetation on soil from erosion has an obvious lag, restoration efforts should be focused on the months before the arrival of the rainy season. In light of various grassland types, the overlay zoning results suggest various restoration patterns of natural repair and manual intervention should be employed for different grasslands. Urgent action is needed to face the challenge and process of grassland degradation and restore its sustainability with shared understanding by taking the stakeholders, collaborations and mutual relationships among different roles into account (e.g., scientist, government and herdsman).

Estimating mountainous plant species richness and diversity for monitoring global change in a protected grassland park

AbstractAssessments of species diversity and richness are essential to understand present ecological and biodiversity conditions for effective conservation management strategies. Biodiversity indicators determine rangeland health and response to grazing, fire regimes and climate change. This research examined species richness, diversity and composition in a protected mountainous grassland. Two data sets, both collected from a 30 × 30 m plot, with similar species composition and cover were combined. One data set was collected using a 100‐step point survey and the other from a series of 16 plots. A single‐factor analysis of variance was used to test if the mean species richness and diversity of the sites differed across the study area. Species accumulation curves were used to determine the relationship between species richness and the number of sampling units per site. The results from fitting a species–area equation showed that the estimated maximum species richness was slightly greater than the observed species pool in all sites, meaning that the sampling units were not adequate (albeit by small margins) to capture all vascular plant species in the sites. Diversity metrics could, thus, be used to monitor species change within grassland plant communities.

Livestock species rather than grazing intensity shape plant guild proportions in interaction with multiple environmental drivers in grassland from the Pyrenees

AbstractQuestions Does grazing management shape the proportion of plant guilds (grasses, legumes, forbs and sedges) in mountain grasslands? Which properties of grazing management have the greatest effect on the proportion of plant guilds: grazer diversity/identity or grazing intensity? Are the effects of grazing management on guild proportion modified by other environmental variables that explain plant guild distribution at broad spatial scales? LocationMountains in the Pyrenees.MethodsWe modelled the proportion of grasses, legumes, forbs and sedges using data from the PASTUS database (n = 96), which contains a wide range of environmental and management conditions due to the high variety of environmental conditions in mountain grasslands in the Pyrenees. We used a machine‐learning algorithm to find those variables that best explained the proportions of each plant guild. We focussed on the differences between the levels of grazing intensity and the grazing species included in the model, and on detecting interactions between grazing variables and climate, topography and soil conditions.ResultsThe proportion of forbs and grasses strongly depended on the grazing livestock species at broad spatial scales. Only soil pH showed a higher overall explanatory power on guild distribution. In general, forbs were favoured in cattle‐ and grasses in sheep‐grazed grasslands, the latter also being favoured on acidic soils, while forbs were favoured in more alkaline soil conditions. However, the effects of those factors (grazing species and soil pH) were modulated through interactions with several other environmental variables, including soil Mg, K and P, and terrain slope. In contrast, grazing intensity was a minor driver of guild distribution.ConclusionsOur results provide information about the relationship between plant functional diversity, indicated by the different plant guild proportions, and grazing management in the Pyrenean grasslands. This information could be useful for developing hypotheses for future experimental studies and for designing policies to improve the management of mountain grasslands.

Diversity of soil bacteria in alpine coal slag mountain grassland in different vegetation restoration years

PurposeThis study aimed to investigate changes in the bacterial diversity of the rhizosphere soil of slag mountains in different years of revegetation restoration.MethodsSeven soil samples were selected from different years of revegetation restoration in Qinghai, China. The bacterial community of each soil was analyzed via high-throughput sequencing using the Illumina MiSeq platform.ResultsStatistical analyses revealed that the diversity of the soil bacterial community was higher in the soil that was restored in 2017 than that in the soils restored from other years. 16S rRNA sequencing revealed that Proteobacteria and Actinobacteria were the dominant phyla. Sphingomonas was the dominant genus. Total nitrogen, available nitrogen, and total potassium influenced the horizontal community structure of the phylum, whereas total nitrogen, organic matter, and pH had a great influence on the horizontal community structure of the phylum. The richness and diversity of the bacterial community in the soils that underwent revegetation restoration were greater in the third year (2017) than in other years. In the seventh year of recovery, the richness and diversity of the bacterial community began to decline.ConclusionThe bacterial diversity of the soil in the coal mine slag mountain improved with the increase in vegetation restoration years.

Microbial activity and habitat heterogeneity in surface soil in a high-mountain grassland landscape (Central Apennines, Italy)

A spatially intensive sampling of surface soil layers (81 stratified-randomized sampling points across a 14 km2 study area) was performed in a high-mountain grassland landscape (Central Apennines, Italy) in July 2017, in order to describe the heterogeneity of microbial habitats and measure their microbial enzymatic activity. Three different microbial habitat types were identified via Hierarchical Cluster Analysis on the basis of 14 (measured or remote-sensed) environmental variables (including chemical and physical soil properties, topographic and geomorphological features and vegetation cover): (i) sub-acidic, at high elevation, with high vegetation cover (of mostly acidophytic/mesophytic species) and high silt content, and the lowest clay content; (ii) sub-acidic, at low elevation, with a high vegetation cover and a very low stone cover, with the highest sand and the lowest silt content, and the highest available phosphorus; (iii) very shallow soil, mainly stone-covered, at high elevation, with the highest pH values, on steep slopes, with the highest content of organic matter and the highest water holding capacity. The third habitat showed the highest enzymatic activity (b-glucosidase, β-cellobiohydrolase and leucine-arylamidase) involved in C and N cycling, while the more acidic and deeper soils, typical of sinkhole or slope areas, favoured the acid phosphomonoesterase activity involved in P cycle thanks to the establishment of the rhizospheric activity of the herbaceous plant species. Moreover, we analysed the relative importance of environmental variables on the total enzyme activities via Boosted Regression Trees (BRT): the results highlighted - for the first time as far as we know - the importance of topographic factors such as slope inclination in predicting the microbial functional capacity in a mountain grassland ecosystem. We conclude that the different enzymatic activity patterns found in the three habitats suggest diverse microbial functions with respect to nutrient cycling, within a small landscape and a relatively homogeneous land-cover.