Mixed Plant Communities Research Articles

Close-range imaging for green roofs: Feature detection, band matching, and image registration for mixed plant communities

Green roofs offer ecological benefits but harsh rooftop environment stressors like heat, water scarcity, and wind can limit optimal plant growth. Monitoring plant health is crucial for optimizing green roof performance and remote sensing provides a non-destructive approach, yet challenges persist in tight, urban settings. This allows for close-range ground monitoring as a viable solution in these emerging environments. Recent studies explored automatic image registration techniques, showing promise in homogeneous settings, but faced uncertainties in mixed species systems or early plant growth stages. Feature detection techniques such as Speeded up Robust Features (SURF) using fixed and moving image spaces have been proposed for alignment. This study aimed to assess feature detection, matching, and image registration techniques in mixed species plant communities on green roofs throughout the growing season. This study developed a sophisticated monitoring system using close-range multispectral sensors for aligning bands in mixed species plant communities, contributing to enhanced green roof management and sustainability. The results of the study showed no significant differences in band alignment accuracy between growth stages for mixed species bush bean/sedum and single species sedum modules, but significant differences were found in single species bush bean systems. Additionally, mixed species modules showed better accuracy compared to single species bush bean modules, indicating that heterogenous systems provide better alignment accuracy due to more diverse feature extractions.

Mapping Foliar C, N, and P Concentrations in An Ecological Restoration Area with Mixed Plant Communities Based on LiDAR and Hyperspectral Data

Interactions between carbon (C), nitrogen (N), and phosphorus (P), the vital indicators of ecological restoration, play an important role in signaling the health of ecosystems. Rapidly and accurately mapping foliar C, N, and P is essential for interpreting community structure, nutrient limitation, and primary production during ecosystem recovery. However, research on how to rapidly map C, N, and P in restored areas with mixed plant communities is limited. This study employed laser imaging, detection, and ranging (LiDAR) and hyperspectral data to extract spectral, textural, and height features of vegetation as well as vegetation indices and structural parameters. Causal band, multiple linear regression, and random forest models were developed and tested in a restored area in northern China. Important parameters were identified including (1), for C, red-edge bands, canopy height, and vegetation structure; for N, textural features, height percentile of 40–95%, and vegetation structure; for P, spectral features, height percentile of 80%, and 1 m foliage height diversity. (2) R2 was used to compare the accuracy of the three models as follows: R2 values for C were 0.07, 0.42, and 0.56, for N they were 0.20, 0.48, and 0.53, and for P they were 0.32, 0.39, and 0.44; the random forest model demonstrated the highest accuracy. (3) The accuracy of the concentration estimates could be ranked as C > N > P. (4) The inclusion of LiDAR features significantly improved the accuracy of the C concentration estimation, with increases of 22.20% and 47.30% in the multiple linear regression and random forest models, respectively, although the inclusion of LiDAR features did not notably enhance the accuracy of the N and P concentration estimates. Therefore, LiDAR and hyperspectral data can be used to effectively map C, N, and P concentrations in a mixed plant community in a restored area, revealing their heterogeneity in terms of species and spatial distribution. Future efforts should involve the use of hyperspectral data with additional bands and a more detailed classification of plant communities. The application of this information will be useful for analyzing C, N, and P limitations, and for planning for the maintenance of restored plant communities.

Priority effects of forbs arriving early: the role of root interaction and asymmetric competition

BackgroundThe priority effect of plant arrival is a key driver of community assembly and ecosystem succession during the restoration of degraded plant communities. However, the significance of the arrival order of different plant functional groups and their interactions with community assemblies remains unclear. Using a phytotron experiment with three fully crossed factors, we investigated the underlying mechanisms of priority effects and their relationships with the biomass and biodiversity effects in mixed plant communities by manipulating the order of arrival of species, isolation of roots, and removal of specific plants.ResultsThe results showed that the strength and direction of priority effects were influenced by arrival order, root interactions, asymmetric competition among species, and their interactions. The identities of early and late-sown species also determined the magnitude of priority effects. The priority effects were stronger in grass-first (24.76%) and legume-first communities (24.48%) than in forb-first communities. The pot biomass of the different priority treatments was highest in grass-first (5.85 g), followed by legume-first (3.94 g) and forb-first (2.48 g). The order of arrival in the mixture significantly affected the net biodiversity effects (P < 0.001), which were driven by dominance effects. The community had lower overall biomass when forbs were sown first, whereas the species grown later had fewer costs with an increased overall net benefit for the resulting community.ConclusionsOur results emphasize that root interactions and asymmetric competition are vital determinants of order-specific priority effects in community assemblies. In addition, the importance of the priority effect of forbs sown first is related to community assembly, which may be a key determinant in successfully establishing a highly diverse community in the early stages of restoration. Species with weak competition should be considered in the early stage of community assembly. The rational use of the priority effect is conducive to improving the quality and efficiency of ecological restoration efforts.

Effect of different diesel treatments on growth of single and mixed plant communities and petroleum hydrocarbon dissipation during rhizoremediation

The use of mixed plant communities has been proposed to address phytotoxicity while improving plant stress tolerance and contaminant degradation. However, there has been conflicting findings on the use of mixed plant community. This study assessed the impact of three diesel treatments on plant growth and TPH dissipation in single and mixed plant communities. This involved greenhouse experiment with Medicago sativa, Festuca arundinacea, and Lolium perenne and Medicago sativa + Lolium perenne with the diesel-spiked soils at 102,000, 151,000 and 320,000 µg kg-1 TPH represented as Treatments 1, 2 and 3 respectively. Plant growth was inhibited with root biomass yield was greater compared to plant shoots especially for F. arundinacea and L. perenne. There was a significant decrease in the root biomass yield of M. sativa, L. perenne, F. arundinacea and M. sativa + L. perenne. The highest TPH dissipation of 81, 69 and 72 % was displayed by L. perenne in the Treatments 1, 2 and 3 respectively. However, TPH dissipation was generally comparable for the vegetated and unvegetated soil and were not significantly different (p&gt;0.05) for the different plants and treatments. The impact of plant communities on the rhizoremediation of TPH-contaminated soils may dependent on factors such as plant species, TPH concentration stress tolerance and benefits of individual plant if mixed plants are to be employed.

Living at the edge: the functional niche occupation of woody plant communities in the submediterranean ecotone.

Submediterranean areas are rich ecotones, where slight modifications in environmental conditions can lead to substantial changes in the composition of plant communities. They thus offer an ideal scenario to examine plant community assembly. In this study, we followed a trait-based approach including intraspecific variability to elucidate (1) the relationship between niche occupancy components and species richness, (2) the processes governing the assembly of these communities and (3) the contribution of intraspecific trait variability in shaping the functional trait space. We measured eight morphological and chemical traits in 405 individuals across 60 plots located in different forest communities (Mediterranean, Eurosiberian and Mixed) coexisting within a submediterranean ecosystem in central Spain. We calculated three niche occupancy components related to Hutchinson's n-dimensional hypervolumes: the total functional volume of the community, the functional overlap between species within the community and the average functional volume per species, and then used null models to explore the relative importance of habitat filtering, limiting similarity and intraspecific variability as assembly patterns. Both habitat filtering and niche differentiation drive the community assembly of Mediterranean communities, whereas limiting similarity and hierarchical competition shape Eurosiberian communities. Intraspecific responses were mostly explained by shifts in species niches across the functional space (changes in the position of the centroids of hypervolumes). Different assembly mechanisms govern the structure of Mediterranean, Eurosiberian and Mixed plant communities. Combining niche occupancy components with a null model approach at different spatial scales offers new insights into the mechanisms driving plant community assembly. Consideration of intraspecific variability is key for understanding the mechanisms governing species coexistence in species-rich ecotones.

From Sphagnum to shrub: Increased acidity reduces peat bacterial diversity and keystone microbial taxa imply peatland degradation

AbstractPeatlands store one‐third of the Earth's carbon. Human activities and climate change‐induced peatland vegetation shift from Sphagnum to shrub may lead to peatland degradation. To understand the ecology and functions of these peatlands, we collected samples from 10 peatland mosaics dominated by Sphagnums, mixed plant communities of Sphagnums, and shrubs across south China. Through sequencing the plant rhizosphere microbiome and measuring peat properties, we explored the plant–soil interactions and identified the keystone microbial taxa in peatlands of three vegetation types. Results showed that peat pH decreased along with the plant community shift from Sphagnum to shrub, which may be due to the accumulation of sulfur and phenolics. Lower pH further reduced bacterial diversity in shrub peatlands as Acidobacteriota became predominant in the keystone taxa. Overall, microbiomes in shrub peatlands showed degraded properties, such as a less stable microbial community dominated by few keystone taxa and the loss of methane‐mitigating microbes. The keystone microbial taxa in Sphagnum peatlands included microbes that utilize insoluble organic substances, mono‐ and oligo‐saccharides. Most importantly, the methanotrophic microbes that oxidize methane only appeared in the keystone taxa of Sphagnum peatlands. Mixed plant community peatlands contained the highest concentrations of iron. Slow‐growing fungi and bacteria were in the keystone microbial taxa, indicating slow decomposition rates in these peatlands. Our study suggests that human activity and climate change‐induced peatland vegetation shift from Sphagnum to shrub leads to an unstable belowground community, indicating the degraded peatland, which may exacerbate in the future.

The diversity of plant communities in different habitats can lead to distinct methanotrophic communities

Methanotrophic communities are susceptible to environmental interference in natural ecosystems. However, little is known about methanotrophs and their drivers in the riparian zone ecosystem. Therefore, the soil methanotrophic community structure, assembly process, and their driving factors were examined in five habitats in the riparian zone ecosystem of Three Gorges Reservoir in China. Soil samples were collected from the woody plant community, perennial plant community, annual plant community, perennial mixed annual plant community, and bare land in the riparian zone areas. We assessed plant community diversity, analyzed soil physiochemical properties, and measured enzyme activities to find the driving factors for the methanotrophic community. The findings revealed that Methylosarcina, Methylocystis, and rice paddy clusters dominated habitats. They preferred different pH levels and plant diversity. The diversity of the soil methanotrophic community was greater in vegetation-covered areas than on bare land. Likewise, the co-occurrence network of soil methanotrophs was more complex in vegetation-covered areas than in bare land, indicating a more stable community structure. Soil nitrogen, catalase, and plant diversity influence stability and diversity. During the transformation from bare land to plant community, the assembly process of the soil methanotrophic community converted from stochastic to deterministic processes, in which dispersal limitation and homogenous selection played prominent roles and were primarily influenced by soil pH and plant diversity. This research helps us understand the evolution of methanotrophs during vegetation restoration. It can also help us find plant communities that can effectively sequester carbon pools and plant them in riparian zones around reservoir systems to maintain soil and water quality.

Facies development of coal seams in the Knurów deposit (Upper Silesia, Poland)

This paper presents the first attempt to develop the facies model of the entire coal deposit belonging to the Carboniferous productive sequence located in the western part of the Upper Silesian Coal Basin. To achieve this objective, six seams from the Knurów deposit were examined. The deposit belongs to the largest producer of coking coal in Europe, which is Jastrzębska Spółka Węglowa SA (Polish state-run coking coal producer). The maceral composition, vitrinite reflectance, ash yield content, moisture content, gross calorific value, and volatile matter yield were determined. Coals from the Knurów deposit are classified as ortho-bituminous and meta-bituminous coals. Their average degree of coalification, determined by vitrinite reflectance, is RO = 0.79% to RO = 1.09%. Petrographic indices and the analysis of facies diagrams were used to develop the facies model. It was shown that the facies development and sedimentological evolution of the Knurów deposit were determined by the river system extended to the upper delta plain. In accordance with the stratigraphic succession, the oldest deposits are dominated by the reed facies (mainly Calamites) growing in oxbow lakes and dry streambeds. With the passage of time, the importance of the river system for the development of the paleo-environment decreased. Transitional bogs with mixed plant communities were formed. This started the conversion of wetlands into areas occupied by wet forest. At the end of the sedimentation of the documented coal seams in the Knurów deposit, lowland bogs (fens), which were subject to frequent fires, dominated the landscape. Based on a detailed maceral analysis and facies diagram analysis, a strong correlation between fault occurrence and coal facies developed under paleo-river influence was displayed. The aim of the study is to show environmental changes during deposit formation in the context of geological exploration.

Long-term effects of artificial nighttime lighting and trophic complexity on plant biomass and foliar carbon and nitrogen in a grassland community.

The introduction of artificial nighttime lighting due to human settlements and transport networks is increasingly altering the timing, intensity, and spectra of natural light regimes worldwide. Much of the research on the impacts of nighttime light pollution on organisms has focused on animal species. Little is known about the impacts of daylength extension due to outdoor lighting technologies on wild plant communities, despite the fact that plant growth and development are under photoperiodic control. In a five‐year field experiment, artificial ecosystems (“mesocosms”) of grassland communities both alone or in combination with invertebrate herbivores and predators were exposed to light treatments that simulated street lighting technologies (low‐pressure sodium, and light‐emitting diode [LED]‐based white lighting), at ground‐level illuminance. Most of the plant species in the mesocosms did not exhibit changes in biomass accumulation after 5 years of exposure to the light treatments. However, the white LED treatment had a significant negative effect on biomass production in the herbaceous species Lotus pedunculatus. Likewise, the interaction between the white LED treatment and the presence of herbivores significantly reduced the mean shoot/root ratio of the grass species Holcus lanatus. Artificial nighttime lighting had no effect on the foliar carbon or nitrogen in most of the grassland species. Nevertheless, the white LED treatment significantly increased the leaf nitrogen content in Lotus corniculatus in the presence of herbivores. Long‐term exposure to artificial light at night had no general effects on plant biomass responses in experimental grassland communities. However, species‐specific and negative effects of cool white LED lighting at ground‐level illuminance on biomass production and allocation in mixed plant communities are suggested by our findings. Further studies on the impacts of light pollution on biomass accumulation in plant communities are required as these effects could be mediated by different factors, including herbivory, competition, and soil nutrient availability.

Temporal dynamics of range expander and congeneric native plant responses during and after extreme drought events.

Climate change is causing range shifts of many species to higher latitudes and altitudes and increasing their exposure to extreme weather events. It has been shown that range-shifting plant species may perform differently in new soil than related natives; however, little is known about how extreme weather events affect range-expanding plants compared to related natives. In this study we used outdoor mesocosms to study how range-expanding plant species responded to extreme drought in live soil from a habitat in a new range with and without live soil from a habitat in the original range (Hungary). During summer drought, the shoot biomass of the range-expanding plant community declined. In spite of this, in the mixed community, range expanders produced more shoot biomass than congeneric natives. In mesocosms with a history of range expanders in the previous year, native plants produced less biomass. Plant legacy or soil origin effects did not change the response of natives or range expanders to summer drought. During rewetting, range expanders had less biomass than congeneric natives but higher drought resilience (survival) in soils from the new range where in the previous year native plant species had grown. The biomass patterns of the mixed plant communities were dominated by Centaurea spp.; however, not all plant species within the groups of natives and of range expanders showed the general pattern. Drought reduced the litter decomposition, microbial biomass, and abundances of bacterivorous, fungivorous, and carnivorous nematodes. Their abundances recovered during rewetting. There was less microbial and fungal biomass, and there were fewer fungivorous nematodes in soils from the original range where range expanders had grown in the previous year. We concluded that in mixed plant communities of range expanders and congeneric natives, range expanders performed better, under both ambient and drought conditions, than congeneric natives. However, when considering the responses of individual species, we observed variations among pairs of congenerics, so that under the present mixed-community conditions there was no uniformity in responses to drought of range expanders versus congeneric natives. Range-expanding plant species reduced soil fungal biomass and the numbers of soil fungivorous nematodes, suggesting that the effects of range-expanding plant species can trickle up in the soil food web.

N limit as a switch node between positive and negative plant-soil feedback: A meta-analysis based on the covariant diagnosis of plant growth and soil factors

Mounting evidence has confirmed the existence of plant-soil feedback, a reflection of plant-soil interaction. However, analysis of ecological feedback pathways remains a challenge. In this study, single and mixed plant communities in different soil ecosystems were screened using strict control systems in global ecosystems to identify the positive or negative feedback effects in indicator plants. Furthermore, the plant components and biomass were identified in each pathway. The significantly changed components indicated pathway factors. As negative feedback increased, the InRR (Response Ratio) of soil organic matter, soil total N, microbial alpha diversity and the symbiotic fungi proportion were significantly up-regulated (P < 0.05). In contrast, the stoichiometric ratio (C: N), water content, and the pathogenic bacteria proportion were downregulated (P < 0.05). However, the positive feedback showed the opposite trend. Importantly, N limit as a transform node between positive and negative plant-soil feedback predicted by Akaike information criterion (AIC > 0.8). Therefore, it has become an important evaluation standard for the inter-species relationship and ecological environment changes under the background of global N deposition. Finally, the feedback values of each sampling site were recalculated over the next 20 years, 50 years, and 100 years based on the global temperature rise and changing rainfall patterns. We also found that global warming and extreme rainfall may change the distribution of interspecies relationships on a global scale, with global warming having the greatest recognisable effect and decreasing the negative feedback layout by 21.7% (P < 0.05). Therefore, this work promotes the cognition of relationship of soil environment, microbial abundance and function, plant diversity and plant- soil feedback model. Meanwhile, it is of great significance to protect species diversity and restore environmental degradation.

Rice–weed competition in response to nitrogen form under high and low transpirational demand

AbstractImplementation of water‐saving irrigation practices in lowland rice results in increased availability of nitrate (NO3−) in the soil and favours germination of upland weeds. Since plant species show a specific preference for either ammonium (NH4+) or NO3− as nitrogen (N) source, changes in both soil NO3− concentration and weed flora may affect the competition between rice and weeds. Further, the transpirational demand of the atmosphere might affect growth and competitiveness of lowland (wetland) and upland (dryland) weeds differently due to their adaptation to different ecological environments. Therefore, the study aimed to evaluate the effects of N source on growth, N uptake and competition between rice and common upland and lowland weeds under high and low vapour pressure deficit (VPD). Two rice (Oryza sativa) varieties (NU838 and KD18) differing in growth characteristics and two weed species (Echinochloa crus‐galli and Solanum nigrum) differing in their natural habitat were selected and grown hydroponically as monoculture or mixed culture at low or high VPD. N was supplied as 75%/25% or 25%/75% NH4+/NO3−. N uptake rates were measured in the first week, whereas dry matter (DM), N concentration in the plant, total N uptake and the activities of nitrate reductase and glutamine synthetase in the fresh leaves were determined two weeks after the onset of treatments. Independent of N source, both rice varieties and E. crus‐galli took up a larger share of NH4+, whereas S. nigrum took up a larger share of NO3−. N uptake of rice and E. crus‐galli was hardly affected by N source, whereas high NO3− led to significantly higher N uptake rates and total N uptake of S. nigrum. NU838 showed a higher competitiveness against weeds than KD18. In competition, high NO3− decreased the competitiveness of E. crus‐galli against NU838 but increased the competitiveness of S. nigrum against NU838. High VPD did not affect DM but increased N uptake of S. nigrum, leading to increased competitiveness of the weed at high transpirational demand. Competitiveness for N uptake appears to be an important trait as the relative N concentration in mixed plant communities was correlated with the activity of N‐assimilating enzymes and leaf growth, with a stronger response in rice than in weeds. Our results support the hypothesis that increased availability of NO3− in aerobic rice soils may be advantageous for the competitiveness of upland weeds, especially at high VPD, whereas it may be disadvantageous for common lowland weeds.

Species patch size at seeding affects the productivity of mixed legume-grass communities

The impact of inter- and intraspecific neighboring plants on mixed legume-grass communities has rarely been explored in relation to seeded species patch size. In this study, two native perennial species, the legume alfalfa (Medicago sativa L.) and the grass tall fescue (Festuca arundinacea L.), were investigated as monocultures and in mixture. A three-year growth experiment was conducted to investigate the effects of plant-plant competitive interactions on fine-scale seeding patterns: monoculture, three different conspecific patch sizes (1.0, 0.5, and 0.25 m side length of squares) and a control in which the seeds were mixed and scattered (i.e., patches were not formed) as in conventional seeding. The results demonstrated significant differences in the mutual effect intensity in all conspecific patch sizes, indicating the presence of grass-legume interactions on mixed plant communities. Smaller patch sizes resulted in better facilitation by higher neighbor effect intensity when compared with a larger patch size and the conventional mixture. Seedings in the smallest patch size of 0.25 m × 0.25 m showed intra- and interspecific competition and significantly improved aboveground productivity compared with the other patch sizes. We directly quantified the variation of species neighbor effect intensity between grass and legume mixtures among different species patch sizes at seeding. Integrating this knowledge into species interaction models in plant community ecology could greatly enhance our understanding of species coexistence in grasslands as well as provide opportunities for manipulating competition to achieve specific agronomic aims.

Advances in Breeding for Mixed Cropping - Incomplete Factorials and the Producer/Associate Concept.

Mixed cropping has been suggested as a resource-efficient approach to meet high produce demands while maintaining biodiversity and minimizing environmental impact. Current breeding programs do not select for enhanced general mixing ability (GMA) and neglect biological interactions within species mixtures. Clear concepts and efficient experimental designs, adapted to breeding for mixed cropping and encoded into appropriate statistical models, are lacking. Thus, a model framework for GMA and SMA (specific mixing ability) was established. Results of a simulation study showed that an incomplete factorial design combines advantages of two commonly used full factorials, and enables to estimate GMA, SMA, and their variances in a resource-efficient way. This model was extended to the Producer (Pr) and Associate (As) concept to exploit additional information based on fraction yields. It was shown that the Pr/As concept allows to characterize genotypes for their contribution to total mixture yield, and, when relating to plant traits, allows to describe biological interaction functions (BIF) in a mixed crop. Incomplete factorial designs show the potential to drastically improve genetic gain by testing an increased number of genotypes using the same amount of resources. The Pr/As concept can further be employed to maximize GMA in an informed and efficient way. The BIF of a trait can be used to optimize species ratios at harvest as well as to extend our understanding of competitive and facilitative interactions in a mixed plant community. This study provides an integrative methodological framework to promote breeding for mixed cropping.

Plant functional group drives the community structure of saprophytic fungi in a grassland biodiversity experiment

AimsSaprophytic fungi are important agents of soil mineralization and carbon cycling. Their community structure is known to be affected by soil conditions such as organic matter and pH. However, the effect of plant species, whose roots provide the litter input into the soil, on the saprophytic fungal community is largely unknown.MethodsWe examined the saprophytic fungi in a grassland biodiversity experiment with eight plant species belonging to two functional groups (grasses and forbs), combining DNA extraction from plant roots, next-generation sequencing and literature research.ResultsWe found that saprophyte richness increased with plant species richness, but plant functional group richness was the best predictor. Plant functional group was also the main factor driving fungal saprophytic community structure. This effect was correlated with differences in root lignin content and C:N ratio between grasses and forbs. In monocultures, root traits and plant functional group type explained 16% of the variation in community structure. The saprophyte taxa detected in mixed plant communities were to a large extent subsets of those found in monocultures.ConclusionsOur work shows that the richness and community structure of the root-associated saprophytic fungi can largely be predicted by plant functional groups and their associated root traits. This means that the effects of plant diversity on ecosystem functions such as litter decomposition may also be predictable using information on plant functional groups in grasslands.

Evaluating Restoration Methods A Cross A Range of Plant Communities Dominated by Invasive Annual Grasses to Native Perennial Grasses

The objectives of the study were to determine whether there are differences in plant community response to restoration methods &amp; to create awareness among the pastoralists/ agro-pastoralists on how to restore degraded rangeland. Six treatments were established: (1) ripping, mulching and seeding (2) ripping, manuling and seeding (3) ripping, mulching, manuling and seeding (4) control. The treatments were arranged in a randomized complete block design with factorial and replicated three times in each plant community. Each treatment plot was 3m by 6m, and depending on the treatment assigned to the plot, measurements for the vegetations were taken from those plots. Seeds of perennials, large tufted and palatable grass species were selected for reseeding purpose i.e., Andropogon canaliculatus, Tetrapogon cenchriformis, Panicum coloratum and Chrysopogon plumolosus. The study was carried out over the last three rainy seasons from 2015/16 and 2017/ 2018. Data were collected from germination to dry matter yield within three years of the experimental years. Accordingly, the result showed as variation clearly observed among the restoration treatments to different plant community. There is a significant difference at (P&lt;0.05) rangeland parameters collected in all Restoration methods in each seasons. A total of 18 species of grasses were identified in the study district. Of the grass species 11(61.1%) species were perennials and 7 (38.9%) species were annuals. In Perennial plant community with Restoration Methods of Ri+Ma+Mu+Se was significant difference at (P&lt;0.05) in the three consecutive seasons in Biomass production. The highest Biomass production was observed in the third season of implementation time which was 2.37 ton/ha while the lowest biomass production was observed in the first season of implementation period in control one which was 1 ton/ha. In Mixed plant community with Restoration Methods of Ri+Ma+Mu+Se was significant difference at (P&lt;0.05) in the three consecutive seasons in Biomass production. The highest Biomass production was observed in the third season of implementation time which was 1.75 ton/ha while the lowest biomass production was observed in the first season of implementation period in control one which was 0.83 ton/ha. Therefore, we conclude that from this finding, perennial plant community with Restoration methods of Ri+Ma+Mu+Se is more effective method to rehabilitate denuded rangeland areas in semi-arid areas and also Annual plant community with Restoration methods of Ri+Ma+Mu+Se has shown dramatic result to improved range resources within short period of time. However, continuous onsite training &amp; practical demonstration was very crucial to enhance the adoption rate of those Restoration methods. Keywords: Restoration Methods, plant community, Germination, Basal cover &amp; Biomass Yield DOI : 10.7176/JBAH/9-19-01 Publication date :October 31 st 2019

Ectomycorrhizal fungal communities in high mountain conifer forests in central Mexico and their potential use in the assisted migration of Abies religiosa.

Abies religiosa forests in central Mexico are the only overwinter refuge of the monarch butterfly and provide important ecosystem services. These forests have lost 55% of their original area and as a consequence, diversity and biotic interactions in these ecosystems are in risk. The aim of this study was to compare the soil fungal diversity and community structure in the Abies religiosa forests and surrounding Pinus montezumae, Pinus hartwegii, and coniferous mixed forest plant communities to provide data on ecology of mycorrhizal interactions for the assisted migration of A. religiosa. We sampled soil from five coniferous forests, extracted total soil DNA, and sequenced the ITS2 region by Illumina MiSeq. The soil fungi community was integrated by 1746 taxa with a species turnover ranging from 0.280 to 0.461 between sampling sites. In the whole community, the more abundant and frequent species were Russula sp. (aff. olivobrunnea), Mortierella sp.1, and Piloderma sp. (aff. olivacearum). The ectomycorrhizal fungi were the more frequent and abundant functional group. A total of 298 species (84 ectomycorrhizal) was shared in the five conifer forests; these widely distributed species were dominated by Russulaceae and Clavulinaceae. The fungal community composition was significantly influenced by altitude and the lowest species turnover happened between the two A. religiosa forests even though they have different soil types. As Pinus montezumae forests have a higher altitudinal distribution adjacent to A. religiosa and share the largest number of ectomycorrhizal fungi with it, we suggest these forests as a potential habitat for new A. religiosa populations.

Density-dependency and plant-soil feedback: former plant abundance influences competitive interactions between two grassland plant species through plant-soil feedbacks

Backgrounds and aimsNegative plant-soil feedbacks (PSFs) are thought to promote species coexistence, but most evidence is derived from theoretical models and data from plant monoculture experiments.MethodsWe grew Anthoxanthum odoratum and Centaurea jacea in field plots in monocultures and in mixtures with three ratios (3:1, 2:2 and 1:3) for three years. We then tested in a greenhouse experiment the performance of A. odoratum and C. jacea in pots planted with monocultures and 1:1 mixtures and filled with live and sterile soils collected from the field plots.ResultsIn the greenhouse experiment, C. jacea produced less aboveground biomass in soil conditioned by C. jacea monocultures than in soil conditioned by A. odoratum monocultures, while the aboveground biomass of A. odoratum in general did not differ between the two monospecific soils. The negative PSF effect was greater in the 1:1 plant mixture than in plant monocultures for A. odoratum but did not differ for C. jacea. In the greenhouse experiment, the performance of C. jacea relative to A. odoratum in the 1:1 plant mixture was negatively correlated to the abundance of C. jacea in the field plot where the soil was collected from. This relationship was significant both in live and sterile soils. However, there was no relationship between the performance of A. odoratum relative to C. jacea in the 1:1 plant mixture in the greenhouse experiment and the abundance of A. odoratum in the field plots.ConclusionsThe response of a plant to PSF depends on whether the focal species grows in monocultures or in mixtures and on the identity of the species. Interspecific competition can exacerbate the negative plant-soil feedbacks compared to intraspecific competition when a plant competes with a stronger interspecific competitor. Moreover, the abundance of a species in mixed plant communities, via plant-soil feedback, negatively influences the relative competitiveness of that species when it grows later in interspecific competition, but this effect varies between species. This phenomenon may contribute to the coexistence of competing plants under natural conditions through preventing the dominance of a particular plant species.

Spatial heterogeneity in plant–soil feedbacks alters competitive interactions between two grassland plant species

Abstract The effects of plants on soil vary greatly between plant species and in mixed plant communities this can lead to spatial variation in plant‐soil feedback (PSF) effects. Such spatial effects are thought to influence plant species coexistence, but the empirical evidence for this hypothesis is limited. Here, we investigate how spatial heterogeneity in PSFs influences plant growth and competition. The experiment was carried out with high and low nutrient soils to examine how these effects depend on soil fertility. We collected soil from field plots planted for three years with monocultures of Anthoxanthum odoratum and Centaurea jacea and tested the performance of the two species in a greenhouse experiment in heterogeneous soils consisting of patches of “own” and “foreign” soils and in soils where the “own” and “foreign” soils were mixed homogeneously. In the test phase, plants were grown in monocultures and in 1:1 mixtures in live or sterilized soils. Overall, A. odoratum in monocultures produced less aboveground biomass in heterogeneous soils than in homogeneous soils. Centaurea jacea produced less belowground biomass in live heterogeneous soils than in live homogeneous soils, but there was no difference between sterile heterogeneous and homogeneous soils. The belowground biomass per patch varied more in pots with live heterogeneous soils than in pots with live homogeneous soils for both plant species, but there was no difference between pots with sterile heterogeneous and homogeneous soils. In pots with plant mixtures, the difference in aboveground biomass between the two competing species tended to be smaller in heterogeneous than in homogeneous soils. In pots with heterogeneous soils, both plant species grown in mixtures produced more aboveground biomass in “foreign” soil patches than in “own” soil patches. The responses of plants to heterogeneous PSFs were not different between low and high nutrient soils. Our results show that spatially heterogeneous PSFs can influence plant performance and competition via reducing the growth inequality between the two competing species by allowing selective growth in foreign soil patches, independent of initial soil nutrient availability. Such effect may slow down exclusion processes and thus promote the coexistence of competing species at the local scale in mixed plant communities. A plain language summary is available for this article.

Community-level plant-soil feedbacks explain landscape distribution of native and non-native plants.

Plant–soil feedbacks (PSFs) have gained attention for their potential role in explaining plant growth and invasion. While promising, most PSF research has measured plant monoculture growth on different soils in short‐term, greenhouse experiments. Here, five soil types were conditioned by growing one native species, three non‐native species, or a mixed plant community in different plots in a common‐garden experiment. After 4 years, plants were removed and one native and one non‐native plant community were planted into replicate plots of each soil type. After three additional years, the percentage cover of each of the three target species in each community was measured. These data were used to parameterize a plant community growth model. Model predictions were compared to native and non‐native abundance on the landscape. Native community cover was lowest on soil conditioned by the dominant non‐native, Centaurea diffusa, and non‐native community cover was lowest on soil cultivated by the dominant native, Pseudoroegneria spicata. Consistent with plant growth on the landscape, the plant growth model predicted that the positive PSFs observed in the common‐garden experiment would result in two distinct communities on the landscape: a native plant community on native soils and a non‐native plant community on non‐native soils. In contrast, when PSF effects were removed, the model predicted that non‐native plants would dominate all soils, which was not consistent with plant growth on the landscape. Results provide an example where PSF effects were large enough to change the rank‐order abundance of native and non‐native plant communities and to explain plant distributions on the landscape. The positive PSFs that contributed to this effect reflected the ability of the two dominant plant species to suppress each other's growth. Results suggest that plant dominance, at least in this system, reflects the ability of a species to suppress the growth of dominant competitors through soil‐mediated effects.