Plant Community Structure Research Articles

Study on the Microclimatic Effects of Plant-Enclosure Conditions and Water–Green Space Ratio on Urban Waterfront Spaces in Summer

In the context of waterfront-space design, this study examines the impact of plant enclosures and the ratio of water bodies to green spaces on the microclimate, aiming to enhance the climate environment and mitigate urban heat. Utilizing Fujian Agriculture and Forestry University as a case study, the research selects the summer solstice as a representative weather condition, conducts field measurements and model validation for four types of waterfront vegetation, and creates 80 scenarios with varying plant enclosures and water to green space ratios using ENVI-met 5.0.2software. This comprehensive analysis seeks to identify the optimal water–green space ratio for waterfront areas. Key findings include: (1) The efficacy and applicability of ENVI-met software for microclimate studies are confirmed. (2) Waterfront plants have cooling and humidifying effects on the microclimate environment. The order of cooling and humidifying effects of different plant community structures was as follows: tree–shrub–grass > tree–grass > shrub–grass > grass. (3) The cooling, humidification, ventilation, and human comfort levels are influenced by the specific enclosure conditions and water to green space ratios; a ratio of 1.8:1 is the most effective for cooling and improving human comfort, while ratios of 4:1 and 1:4 are better for humidification and ventilation. These results offer valuable insights for designing waterfront spaces in hot and humid climates.

Allelopathic potentials of surrounding vegetation on seedling establishment of alpine cushion Arenaria polytrichoides Edgew.

Abstract When facilitating other species and sustaining plant community structures and biodiversity, alpine cushion plants simultaneously experience negative feedback effects from surrounding vegetation. However, the impact of surrounding vegetation on cushion dynamics remains poorly understood, particularly in terms of allelopathic potentials. To investigate the allelopathic potentials of surrounding vegetation on seedling establishment of the typical cushion plant Arenaria polytrichoides Edgew. along an elevational gradient, we extracted potential allelopathic compounds and tested their impacts on seed germination and seedling growth of A. polytrichoides. In addition, exclusion experiments using activated carbon were conducted to further elucidate these effects. Our results demonstrate that surrounding vegetation exhibits certain allelopathic potentials on A. polytrichoides seedling establishment, with variations observed based on elevation, source and concentration of allelopathy compounds, as well as growing season. Specifically, low-elevation vegetation exerts pronounced suppression on seedling establishment. Conversely, higher-elevation vegetation generally shows no effect on seed germination but stimulates seedling growth through allelopathy mechanisms. Moreover, aboveground vegetation predominantly inhibits both seed germination and seedling growth in low-elevation communities; however, the effects of belowground vegetation depend on elevation and extract concentration levels. The identified allelopathic potentials of surrounding vegetation significantly influence the population dynamics of cushion A. polytrichoides by potentially accelerating population degeneration in lower-elevation communities while ensuring consistent population recruitment and expansion in higher-elevation communities.

2011–2015年洞庭湖洲滩群落植物生态型、生活型和生长型组成数据集

Analyzing plant life-forms and ecotypes can provide deep insights into the relationship between plant community structure and environmental conditions, and plant life-forms play an important role in understanding the emergence, development, and succession laws of plant community. An investigation was made on the species life-forms and ecotypes of wetland plants in Dongting lake wetland. In accordance with the unified monitoring specifications of the Chinese Ecosystem Research Network (CERN), the Dongting Lake Wetland Ecosystem Observation and Research Station conducts long-term positioning monitoring on the species composition, species life-forms, growth forms and ecotypes of typical beach vegetation in the wetland ecosystem in response to the changing hydrological conditions of Dongting Lake. The dataset of long-term monitoring conducted on three typical plant communities (Carex sp., Miscanthus lutarioriparius and Polygonum hydropiper) in Dongting Lake wetland has been verified by experts to ensure the accuracy of the data. We then classified and processed the data to obtain the dataset of community composition of plant life-forms, growth forms and ecotypes on Dongting Lake beach (2011–2015). The dataset covers a total of 8 indicators, namely species name, Latin name, life-form, growth form, ecotype according to light intensity, ecotype according to water requirement, ecotype based on soil pH and ecotype according to responses sediment burial. This dataset comes with detailed background information to ensure its consistency across both spatial and temporal dimensions. This dataset comes with detailed background information about site information and site management records to ensure its consistency across both spatial and temporal dimensions. This dataset can provide support for the analysis of the classification of plant life forms and the composition and structure of ecotypes, and serve as valuable reference for further study of vegetation succession in Dongting Lake wetland.

Losses of low-germinating, slow-growing species prevent grassland composition recovery from nutrient amendment.

Nutrient enrichment often alters the biomass and species composition of plant communities, but the extent to which these changes are reversible after the cessation of nutrient addition is not well-understood. Our 22-year experiment (15 years for nutrient addition and 7 years for recovery), conducted in an alpine meadow, showed that soil nitrogen concentration and pH recovered rapidly after cessation of nutrient addition. However, this was not accompanied by a full recovery of plant community composition. An incomplete recovery in plant diversity and a directional shift in species composition from grass dominance to forb dominance were observed 7 years after the nutrient addition ended. Strikingy, the historically dominant sedges with low germination rate and slow growth rate and nitrogen-fixing legumes with low germination rate were unable to re-establish after nutrient addition ceased. By contrast, rapid recovery of aboveground biomass was observed after nutrient cessation as the increase in forb biomass only partially compensated for the decline in grass biomass. These results indicate that anthropogenic nutrient input can have long-lasting effects on the structure, but not the soil chemistry and plant biomass, of grassland communities, and that the recovery of soil chemical properties and plant biomass does not necessarily guarantee the restoration of plant community structure. These findings have important implications for the management and recovery of grassland communities, many of which are experiencing alterations in resource input.

Response of species dominance and niche of plant community to wetland degradation along alpine lake riparian.

Alpine wetland degradation threatens riparian biodiversity and ecological balance. Our study, conducted in July 2020 along the northern and eastern shores of Qinghai Lake, seeks to unravel the impacts of such degradation on plant species dominance and ecological niches, using advanced network analysis methods to explore the dynamics and survival strategies of plant species. We applied a space-to-time method to delineate three wetland degradation stage: a healthy swamp wetland, a slightly degraded wet meadow, and a degraded dry meadow. Six representative sampling points were chosen. At each point, three sample lines were randomly established, radiating outward from the center of the lake wetland, with each stage of degradation meticulously examined through three replicates to assess the plant communities in terms of species composition, plant height, coverage, and abundance. The results indicated: Species such as Kobresia tibetica and Leymus secalinus exhibit remarkable abundance across various stages of wetland degradation, indicating a robust tolerance to these conditions. This observation, coupled with the complexity of plant community structures in degrading wetlands, suggests that such intricacy cannot be solely attributed to the dominance of particular species. Instead, it is the result of a diverse array of species adapting to fluctuating water levels, which promotes increased species richness. Despite the prominence of species that exhibit rapid growth and reproduction, the ecological significance of less abundant species in contributing to the community's complexity is also notable. Changes in habitat conditions due to wetland degradation facilitate both competitive and cooperative interactions among species, highlighting the dynamic nature of these ecosystems. Our analysis shows no significant linear relationship between the ecological niche overlap values and niche widths of plant species. However, the strategies employed by dominant species for competition and resource acquisition, as observed in the ecological niche overlap networks, underscore the adaptive capacity of plant communities. These insights underscore the need for tailored restoration strategies to conserve the biodiversity of alpine lake riparian ecosystems. This research not only sheds light on the resilience and adaptability of ecosystems in the Qinghai-Tibetan Plateau but also offers valuable lessons for the conservation of similar habitats worldwide. Our findings underscore the need for tailored restoration strategies to conserve the biodiversity of alpine lake riparian ecosystems. This research not only sheds light on the resilience and adaptability of ecosystems in the Qinghai-Tibetan Plateau but also offers valuable lessons for the conservation of similar habitats worldwide.

A Study on the Dust Retention Effect of the Vegetation Community in Typical Urban Road Green Spaces—In the Case of Ying Tian Street in Nanjing City

This study aimed to investigate the association between the plant community structure, leaf surface microstructure, nutrient element content, and the dust-retention capacity of garden plants in urban road green spaces. The plant community located along Ying Tian Street in Nanjing City was selected as the focal point of the investigation. Random sampling was performed on the urban road green spaces, determining the amount of dust trapped in plant leaves. Subsequently, the microstructure of the leaf surface was observed, and the content of nutrient elements in the plant leaves was determined. The study also entailed an analysis of the interrelationships between the leaf surface microstructure, plant nutrient element content, and the dust-retention ability of the plants. The findings of this study revealed notable variations in the dust-retention capacity of garden plants and the community structure observed along Ying Tian Street. Among the tree species, Cedrus deodara and Ginkgo biloba exhibited a remarkable dust-retention ability per unit leaf area. Among the shrub species, Abelia × grandiflora and Loropetalum chinense displayed a strong dust-retention capacity per unit leaf area. Similarly, Ophiopogon japonicus and Cynodon dactylon exhibited a robust dust-retention ability per unit leaf area among the herbaceous plants. Furthermore, the dust-retention ability of the plants exhibited a strong positive correlation with the dimensions of leaf stomata, specifically the length and width, while displaying a moderate positive correlation with the width of grooves on the upper and lower surfaces of the leaves. Conversely, the thickness of the leaves did not exhibit a significant correlation. Additionally, the nitrogen content of the leaves exerted a significant influence on the dust-retention ability of the plants (p < 0.05), although the phosphorus and potassium content factors did not exhibit a significant influence (p > 0.05). Based on the findings, it is recommended to prioritize the utilization of plants with robust dust-retention abilities, such as C. deodara, A. grandiflora, O. japonicus, and C. dactylon, and implement a mixed planting approach encompassing a combination of trees, shrubs, and herbaceous plants within urban road green spaces.

Insect root feeders incur negative density-dependent damage across plant species in an alpine meadow.

Although herbivores are well known to incur positive density-dependent damage and mortality, thereby likely shaping plant community assembly, the response of belowground root feeders to changes in plant density has seldom been addressed. Locally rare plant species (with lower plant biomass per area) are often smaller with shallower roots than common species (with higher plant biomass per area) in competition-intensive grasslands. Likewise, root feeders are often distributed in the upper soil layers. We hypothesized, therefore, that root feeders would incur negative density (biomass)-dependent damage across plant species. To test this hypothesis, we investigated the diversity and abundance of plant and root feeder species in an alpine meadow and determined the diet of the root feeders using metabarcoding. Across all species, root feeder load decreased with increasing aboveground plant biomass, root biomass, and total plant biomass per area, indicating a negative density dependence of damage across plant species. Aboveground plant biomass per area increased with increasing individual plant biomass and root depth per area across species, suggesting that rare plant species were smaller in size and had shallower root systems compared to common plant species. Both root biomass per area and root feeder biomass per area decreased with soil depth, but the root feeder biomass decreased disproportionately faster compared to root biomass with increasing root depth. Root feeder load decreased with increasing root depth but was not correlated with the feeding preference of root feeder species. Moreover, the prediction derived from a random process incorporating vertical distributions of root biomass and root feeder biomass significantly accounted for interspecific variation in root feeder load. In conclusion, the data indicate that root feeders incur negative density-dependent damage across plant species. On this basis, we suggest that manipulative experiments should be conducted to determine the effect of the negative density-dependent damage on plant community structure and that different types of plant-animal interactions should be concurrently examined to fully understand the effect of plant density on overall herbivore damage across plant species.

Do degraded grasslands provide a better habitat for plateau pika? —Testing the nutritional hypothesis

Besides overgrazing by livestock, browsing by small native mammals, such as plateau pikas, is considered an important cause of alpine grassland degradation on the Qinghai-Tibetan Plateau (QTP). Preference of pikas for degraded grasslands, resulting in increased population density, has been proposed as the most accepted hypothesis. However, few studies have explored the mechanisms underlying the habitat preferences of pikas. Herein, we analyzed aboveground biomass, community composition, forage quality of lightly and severely degraded alpine grasslands, and the diet and nutritional intake of pikas living there to test whether the plant community structure and associated nutrient composition of severely degraded grasslands are more suitable for pikas in terms of dietary and nutritional requirements. Our results showed that the plant community structure differed between lightly and severely degraded grasslands, with lightly degraded grasslands containing more food plants preferred by pikas. The nutritional composition of plants in severely degraded grasslands was less suitable for pikas than that in lightly degraded grasslands. Our results reject the nutritional hypothesis that severely degraded grasslands meet the dietary and nutritional needs of pikas better. We conclude that food and nutrient selection are not drivers of population increase in pikas in the severely degraded grasslands of the QTP.

Later-melting rather than thickening of snowpack enhance the productivity and alter the community composition of temperate grassland

Snowpack is closely related to vegetation green-up in water-limited ecosystems, and has effects on growing-season ecosystem processes. However, we know little about how changes in snowpack depth and melting timing affect primary productivity and plant community structure during the growing season. Here, we conducted a four-year snow manipulation experiment exploring how snow addition, snowmelt delay and their combination affect aboveground net primary productivity (ANPP), species diversity, community composition and plant reproductive phenology in seasonally snow-covered temperate grassland in northern China. Snow addition alone increased soil moisture and nutrient availability during early spring, while did not change plant community structure and ANPP. Instead, snowmelt delay alone postponed plant reproductive phenology, and increased ANPP, decreased species diversity and altered species composition. Grasses are more sensitive to changes in snowmelt timing than forbs, and early-flowering forbs showed a higher sensitivity compared to late-flowering forbs. The effect of snowmelt delay on ANPP and species diversity was offset by snow addition, probably because the added snow unnecessarily lengthens the snow-covering duration. The disparate effects of changes in snowpack depth and snowmelt timing necessitate their discrimination for more mechanistic understanding on the effects of snowpack changes on ecosystems. Our study suggests that it is essential to incorporate non-growing-season climate change events (in particular, snowfall and snowpack changes) to comprehensively disclose the effects of climate change on community structure and ecosystem functions.

Plant size traits are key contributors in the spatial variation of net primary productivity across terrestrial biomes in China

Understanding the spatial variability of ecosystem functions is an important step forward in predicting changes in ecosystems under global transformations. Plant functional traits are important drivers of ecosystem functions such as net primary productivity (NPP). Although trait-based approaches have advanced rapidly, the extent to which specific plant functional traits are linked to the spatial diversity of NPP at a regional scale remains uncertain.Here, we used structural equation models (SEMs) to disentangle the relative effects of abiotic variables (i.e., climate, soil, nitrogen deposition, and human footprint) and biotic variables (i.e., plant functional traits and community structure) on the spatial variation of NPP across China and its eight biomes. Additionally, we investigated the indirect influence of climate and soil on the spatial variation of NPP by directly affecting plant functional traits.Abiotic and biotic variables collectively explained 62.6 % of the spatial differences of NPP within China, and 28.0 %–69.4 % across the eight distinct biomes. The most important abiotic factors, temperature and precipitation, had positive effects for NPP spatial variation. Interestingly, plant functional traits associated with the size of plant organs (i.e., plant height, leaf area, seed mass, and wood density) were the primary biotic drivers, and their positive effects were independent of biome type. Incorporating plant functional traits improved predictions of NPP by 6.7 %–50.2 %, except for the alpine tundra on the Qinghai-Tibet Plateau.Our study identifies the principal factors regulating NPP spatial variation and highlights the importance of plant size traits in predictions of NPP variation at a large scale. These results provide new insights for involving plant size traits in carbon process models.

Forest species diversity and community composition in the northern Western Ghats, India

ABSTRACT Background The northern Western Ghats (NWG) – a part of the Western Ghats and Sri Lanka biodiversity hotspot supports tropical forests of conservation priority, due to anthropogenic intensification. Woody species diversity and ecology in NWG is poorly studied, necessitating the knowledge of spatial variability in species and underlying environmental factors, for effective conservation. Aims We described woody plant community composition and related it to climate data across a latitude of 1.4 degrees to obtain information about spatial and environmental variation to support protected area planning. Methods To estimate abundance, importance value index, diversity indices and rank – abundance, we recorded woody species in 144 plots across 12 sites. Elevation, temperature, rainfall, humidity data were related to diversity descriptors in a canonical correspondence analysis. Results We recorded 10,291 trees representing 187 species of 52 families. Divergent geo-climatic factors were related to distinct plant community structures, elevation and humidity being the most influential drivers of plant diversity and density. Numerous rare species were found restricted to environmentally distinct forests. Conclusion The wide-ranging environment and corresponding variations in forest community composition across the narrow latitudinal range of the study area revealed the importance of including such gradients in planning future protected areas in the NWG.

Microbial inoculation alters rhizoplane bacterial community and correlates with increased rice yield

Microbial inoculants are recognized as environmentally friendly methods to promote plant growth and improve soil properties. However, the effects of inoculation on the rhizosphere and rhizoplane community structure of plants remain poorly documented and need further investigation. Rhodopseudomonas palustris (R. palustris) strain has nitrogen fixing ability and Bacillus subtilis (B. subtilis) strain is a plant growth-promoting rhizobacterium (PGPR). In this study, we investigated the effects of single and co-inoculation with R. palustris and B. subtilis on the increase of rice yield as well as on the microbial communities in the rhizosphere and rhizoplane of rice through potting experiments, respectively. The results showed that inoculation significantly increased rice yield and seed setting rate, with co-inoculation raising the yield by up to 13.7%. Inoculation influenced both rhizosphere and rhizoplane community structures and functions, amplifying the differences between them. The most significant changes were brought about by the combined inoculation treatment. Co-inoculation with R. palustris and B. subtilis had a synergistic effect. The profound alterations of rhizoplane bacterial community structures and functions were proved to be positively correlated with rice yield and seed setting rate (r = 0.59–0.76, p < 0.05). These results provide new ideas for the investigation of the potential microbiological mechanisms of microbial co-inoculation in practical agricultural applications.

Effects of short- and long-term plant functional group loss on alpine meadow community structure and soil nutrients.

The rapid loss of global biodiversity can greatly affect the normal functioning of ecosystems. However, how biodiversity losses affect plant community structure and soil nutrients is unclear. We conducted a field experiment to examine the short- and long-term effects of removing plant functional groups (Gramineae, Cyperaceae, legumes, and forbs) on the interrelationships among the species diversity, productivity, community structure, and soil nutrients in an alpine meadow ecosystem at Menyuan County, Qinghai Province. The variations in the species richness, above- and belowground biomass of the community gradually decreased over time. Species richness and productivity were positively correlated, and this correlation tended to be increasingly significant over time. Removal of the Cyperaceae, legumes, and other forbs resulted in fewer Gramineae species in the community. Soil total nitrogen, phosphorus, organic matter, and moisture contents increased significantly in the legume removal treatment. The removal of other forbs led to the lowest negative cohesion values, suggesting that this community may have difficulty recovering its previous equilibrium state within a short time. The effects of species removal on the ecosystem were likely influenced by the species structure and composition within the community. Changes in the number of Gramineae species indicated that they were more sensitive and less resistant to plant functional group removal. Legume removal may also indirectly cause distinct community responses through starvation and compensation effects. In summary, species loss at the community level led to extensive species niche shifts, which caused community resource redistribution and significant changes in community structure.

Differential Analysis of Island Mountain Plant Community Characteristics: Ecological Sensitivity Perspectives

Island plants form the foundation for maintaining the ecology of an island. With the development of the island’s infrastructure, its ecosystems become damaged to a certain extent. A comprehensive understanding of island habitats and plant community characteristics is crucial for the development of island plant communities. This paper focuses on Pingtan Island in Fujian Province, China, as the research subject. Firstly, considering the significance of the wind environment on the island, this study constructed a wind environment model for the entire island of Pingtan to evaluate the ecological sensitivity from a macro perspective. Subsequently, 33 typical sample plots were selected based on different ecologically sensitive areas to conduct a micro-survey and the characterization of the montane plant communities on Pingtan Island. The findings reveal that (1) Pingtan Island’s ecological sensitivity is dominated by areas with ecological insensitivity (35.72%), moderate ecological sensitivity (33.99%), and high ecological sensitivity (18.02%). The soil texture, wind environment, and land use type are the primary influencing factors in the ecological sensitivity of Pingtan Island. (2) A total of 47 families, 82 genera, and 93 species of plants were investigated in a typical sample site in the mountainous area of Pingtan Island. The plant community structure was dominated by the successional stage of shrubs and herbs. There is some similarity in the plant composition of different ecologically sensitive areas. High ecologically sensitive areas have more species. As sensitivity increases, the dominant species in the three ecologically sensitive areas continue to undergo plant succession from Acacia confusa to Pinus thunbergii to Eurya emarginata. (3) Both community characteristics and species diversity vary between sensitive areas. The canopy density (CD) and the mean height of tree layer (MHTL) are higher in moderate ecologically sensitive areas. The mean tree diameter at breast height (MDBH) and the mean height of shrub layer (MHSL) are higher in high ecologically sensitive areas, while the mean height of herb layer (MHHL) is higher in extreme ecologically sensitive areas. Four diversity indicators increase with increasing sensitivity. In the moderate and high ecologically sensitive areas, Casuarina equisetifolia and A. confusa thrive, with Pinus thunbergii showing the opposite trend. However, species diversity is better characterized by A. confusa and P. thunbergii, with C. equisetifolia being the least diverse. Both the community characteristics and species diversity of P. thunbergii are optimal in extreme ecologically sensitive areas. In this study, the ecological sensitivity of Pingtan Island and the characteristics of montane plant communities were systematically analyzed to explore more stable montane plant communities on the island, aiming to provide a scientific basis and model reference for the ecological restoration and sustainable development of Pingtan Island and other islands.

Seasonal and habitat dependence of plant species, functional and phylogenetic diversity in agricultural landscapes

The biodiversity of agricultural landscapes is under significant threat, while non-agricultural habitats within these landscapes play a crucial role in biodiversity conservation. There has been limited investigation into how plant species, functional and phylogenetic diversity varies across different seasons and habitats in agricultural landscapes. Thus, we carried out a survey of the plant communities in non-agricultural habitats in China's lower Yellow River plain. We investigated the diversity features of plant functionality, phylogeny, and plant species. We compared differences in plant community structure using non-metric multidimensional scaling analysis and tested phylogenetic signal using phylogenetic methods. Our analysis of plant community and diversity characteristics revealed significant differences in plant community structure between seasons and habitats, with the season having a more significant impact. The levels of plant species, functional, and phylogenetic diversity followed a seasonal pattern, with spring seeing the highest values and autumn seeing the lowest. Woodland and hedgerow habitats had the highest levels of diversity, while field roads had the lowest. The community phylogenetic structure of non-agricultural habitats was relatively concentrated and mainly influenced by human interference and environmental filtering. These findings offer scientific support for the preservation of ecosystem services and biodiversity in agricultural landscapes.

СОВРЕМЕННОЕ СОСТОЯНИЕ РАСТИТЕЛЬНЫХ СООБЩЕСТВ ТЕРРИТОРИИ ОЗЕРА БОЛЬШОЕ ВАВАЙСКОЕ

This article analyzes the current state of plant communities on the territory of Lake Bolshoye Vavayskoye. The study covers the abundance, distribution and ecological relationships of the plant world.&#x0D; The article presents the results of field research conducted in different seasons of the year. The composition and structure of plant communities, as well as their functional characteristics, are described. Special attention is paid to the analysis of the impact of anthropogenic activities on the state of plant communities and their biodiversity.&#x0D; The study found that the plant communities of Lake Bolshoye Vavayskoye are characterized by a high level of biodiversity. In the studied phytocenoses (shrub larch with dwarf cedar, cedar dwarf lingonberry-ledum, lingonberry-lichen larch, fir-spruce moss, fir-spruce shrub, meadow, etc.) grow 283 species of vascular plants, which represent 18.03% of the total number of vascular plants o. Sakhalin, 5 rare plant species listed in the Red Books of the Russian Federation and the Sakhalin Region were also identified, such as Picea glehnii, Taxus cuspidata, Nuphar pumila, Nymphaea tetragona, Arália cordata. However, the study also showed that anthropogenic impact on the lake has a negative impact on the state of plant communities. In particular, signs of water pollution and deforestation have been identified, which leads to a decrease in biodiversity and deterioration of the environmental situation.&#x0D; The authors of the article draw attention to the importance of preserving this natural resource and its environmental sustainability, since in recent decades the territory has undergone anthropogenic impact. The study also highlights the importance of long-term monitoring and environmental control of the area to ensure the conservation of the lake's biodiversity and ecosystems for future generations. The results of the study may be useful for organizing nature conservation and developing an environmentally sustainable approach to the use of resources in the region.

The natural vegetation cover of Al-Dafna plateau in Northeast Tobruk, Libya.

The main objective of this study is to assess the current status of the vegetative cover and the biological diversity in Al-Dafna plateau, as the selected study area has never been botanically studied before. A vegetation survey was conducted in the period between 2019-2022 for three consecutive growing seasons. The total number of the recorded plant species surveyed in the study area is 182 species belonging to 36 different families and 139 genera of vascular plants, representing 8.71% of the total species, 16.46% of total genera and 24.82% of total plant families in Libyan flora. These species were classified into three major groups according to their duration (life-span) as follows 62 perennial (33.51%), 118 annual (65.38 %) and 2 biennial species (1.09%). The distribution among the collected plants was characterised by a high proportion of annuals. Asteraceae had the highest contribution 31 species (17%), followed by Fabaceae 21 species (12%), Amaranthaceae 19 species (10%), Brassicaceae 16 species (9%) and Poaceae 12 species (7%). The results showed the largest genera were Plantago L. and Polygonum L. as each genus contained 5 species. Moreover, thirteen wild medicinal plant species were recorded. Importantly, six endemic species were recorded in the study area, representing 7% of the total endemic plant species in Libya. This study concludes that there is a significant diversity of plant species in the area of study. From this study, it seems that overgrazing has the grandest impact on vegetation cover in Al-Dafna plateau. The results of the present research suggest that conservation strategies should be taken to preserve the plant community structure in Al-Dafna plateau.

Utilizing treated wastewater for pasture irrigation: Effects on productivity, plant community structure and soil properties

AbstractSurplus wastewater accumulates in winter and requires a discharging solution. In our study we examined the effects of using treated wastewater (TWW) as supplemental pasture irrigation in winter. To test the effect of TWW irrigation on the vegetation and soil, 10 grazing prevention exclosures were established at Ramat‐Hanadiv Park, Israel, with half of them irrigated with TWW. Soil and vegetation were sampled during 2 years of irrigation and 1 year after cessation of irrigation. Vegetation composition, species richness, and productivity were sampled at the peak of the growing season and various indices of herbage quality were measured. Our results show that irrigation with wastewater increased herbage production by an average of 38% and total pasture protein production by 9% relative to the control subplots. Conversely, TWW irrigation decreased plant protein content while increasing herbage fibre content and lowering its digestibility. Over a period of 2 years, species richness decreased in the irrigated subplots. Most of the soil indices examined were not affected by irrigation, but in the irrigation subplots, sodium values and the sodium adsorption‐ratio were higher than in areas without irrigation. Additional resources in winter enabled the plants to grow rapidly and increased interplant competition. Changes in vegetation composition were revealed through functional group reshuffling and species richness decline. The results of our study show that wastewater irrigation causes an increase in productivity but a decrease in forage quality. At the pastoral system level, the significant increase in productivity leads to increased availability of protein and herbage for animals.

Contrasting effects of sheep and cattle grazing on foliar fungal diseases by changing plant community characteristics

Abstract Pathogens are ubiquitous in ecosystems and play a key role in affecting host community structure. In grasslands, large grazing animals such as cattle and sheep have been shown to affect foliar fungal pathogens. However, theory and empirical studies have come to conflicting conclusions because grazers can directly and indirectly impact pathogens through a wide variety of mechanisms and various grazers may impact pathogens in different ways. A better understanding of the mechanisms by which grazers impact pathogens is important for a fundamental understanding of herbivore pathogen interactions and also to optimise grazing managements to reduce pathogen outbreaks. Here, we investigate multiple mechanisms by which livestock grazing impacts foliar fungal pathogens in grasslands. We integrate a large‐scale grazing experiment, with a removal experiment manipulating plant density and litter biomass, to identify direct and indirect effects of two herbivores on pathogens with different life histories (biotrophs and necrotrophs), in a temperate grassland in northeast China. We found that grazing by cattle and sheep had contrasting impacts: cattle grazing significantly reduced pathogen load, of both biotrophs and necrotrophs, whereas sheep grazing increased biotrophic pathogen load, but did not affect the necrotrophs. The grazing effects were mostly indirect and mediated by different impacts of the herbivores on plant community structure. Cattle grazing reduced pathogen load because it reduced the abundance of susceptible, fast‐growing plants, and the overall density of plants, while sheep grazing increased pathogen infection because it reduced the abundance of resistant plant species. Plant diversity also reduced pathogen infection but these effects were independent of the herbivores. Our results show that different herbivores can have contrasting impacts on pathogen infection through contrasting impacts on host community competence. This suggests the importance of considering multiple mechanisms simultaneously to evaluate the impact of herbivores on host‐pathogen interactions. Read the free Plain Language Summary for this article on the Journal blog.

Most suitable plant communities for the slope reclamation of the Zhengzhou-Xinxiang section of the Beijing-Hong Kong-Macao expressway.

The construction of expressways in China has produced diverse habitats along slopes characterized by steep gradients, uneven water distribution, poor soil conditions, and no routine maintenance. Manually planting beneficial species is an essential method of effectively improving slope soils to prevent soil erosion. However, few studies have evaluated the reclamation effects and plant community composition and structure used to restore slopes along expressways. This study focused on the Zhengzhou-Xinxiang section of the Beijing-Hong Kong-Macao Expressway. A total of 10 representative plant communities were evaluated using the analytic hierarchy process (AHP)-fuzzy integrated evaluation method. The sites were divided into four layers, namely, plant communities, soil nutrients, soil physical properties, and other ecological factors, and 14 indicators were assessed. The evaluation results showed that four of these plant communities (PCs) were excellent, three PCs were good, one PC was normal, two PCs were poor. The four excellent PCs had high Shannon-Wiener index, pielou index, richness index or community productivity. It is worth noting that most excellent plant community structures were tree + shrub + herb. Based on these results, we recommend that fill slopes should be restored using a combination of trees, herbs, and shrubs; also, the vegetation should include native plants, such as B. papyrifera, U. pumila, A. fruticosa, and Cynodon dactylon (L.). This study could provide ideas for plant community composition and structure of new highway slopes in similar climate environment, and provide theoretical support for plant community composition and structure and soil improvement for the existing slope.