Adaptation of plant‐mycorrhizal interactions to moisture availability in prairie restoration

The strength and direction of plant response to inoculation with arbuscular mycorrhizal fungi (AM fungi) is dependent on both abiotic and biotic contexts, often generating patterns of AM fungal mediation of plant adaptation. However, knowledge of plant‐community level effects of these interactions in grassland restoration is limited. We conducted a field inoculation experiment by inoculating five plant species native to a drier prairie and five plant species native to a moister prairie with mycorrhizal fungal communities from each prairie type. Species were paired by genus or family to account for phylogenetic effects. The inoculated plants were transplanted to study plots seeded with a restoration seed mix. Plots were manipulated to create either moister or drier conditions similar to environments of the plant species and mycorrhizal communities. In both transplanted and seeded plant species, we found that only drier prairie‐range species benefited from moisture‐regime matched AM fungal inoculum. Other seeded prairie plant species demonstrated a negative response to inoculation, likely due to the earlier successional stage of these species. Additionally, nonseeded plants benefited from inoculation in different ways: native nonseeded plants had highest cover with drier prairie inoculum in drier conditions, while nonnative plants had highest cover with moister prairie‐origin inoculum. These results suggest that use of local AM fungi may be particularly important in restorations at drier sites, even at relatively small differences in moisture availability. Further, specific knowledge of relative responsiveness of seeded plant species and nonseeded plant species to AM fungal inoculation will be useful in planning restorations.     

Sources of inocula influence mycorrhizal colonization of plants in restoration projects: a meta‐analysis

Inoculation may influence mycorrhizal colonization and provide benefits to plants in restoration projects. However, it is unclear whether inoculation has consistent effects across ecosystem types, if it has long‐term effects on colonization, and whether sources of inocula differ in their effectiveness. To address these issues, we performed a meta‐analysis of published restoration studies across a variety of ecosystems to examine the effects of mycorrhizal inoculation on mycorrhizal establishment and plant growth under field conditions. Although we included trials from a variety of geographic locations, disturbance types, and ecosystem types, the majority were based in temperate ecosystems in the Northern Hemisphere, and fewer trials were from tropical ecosystems. Across ecosystem types, we found that inoculation consistently increased the abundance of mycorrhizal fungi in degraded ecosystems, and thus improved the establishment of plants. These benefits did not significantly attenuate over time. Moreover, inocula from different sources varied in their effects on mycorrhizal colonization. Inocula sourced from reference ecosystems and inocula with specific fungal species yielded higher increases in mycorrhizal colonization than did inocula from commercial sources. These results suggest that inocula source matters, and that an initial investment into mycorrhizal inoculation could provide lasting benefits for facilitating the establishment of the below‐ and aboveground components of restored ecosystems.     

Management of indigenous plant-microbe symbioses aids restoration of desertified ecosystems

Disturbance of natural plant communities is the first visible indication of a desertification process, but damage to physical, chemical, and biological soil properties is known to occur simultaneously. Such soil degradation limits reestablishment of the natural plant cover. In particular, desertification causes disturbance of plant-microbe symbioses which are a critical ecological factor in helping further plant growth in degraded ecosystems. Here we demonstrate, in two long-term experiments in a desertified Mediterranean ecosystem, that inoculation with indigenous arbuscular mycorrhizal fungi and with rhizobial nitrogen-fixing bacteria not only enhanced the establishment of key plant species but also increased soil fertility and quality. The dual symbiosis increased the soil nitrogen (N) content, organic matter, and hydrostable soil aggregates and enhanced N transfer from N-fixing to nonfixing species associated within the natural succession. We conclude that the introduction of target indigenous species of plants associated with a managed community of microbial symbionts is a successful biotechnological tool to aid the recovery of desertified ecosystems.     

Biochar soil amendments in prairie restorations do not interfere with benefits from inoculation with native arbuscular mycorrhizal fungi

Little of the historical extent of tallgrass prairie ecosystems remains in North America, and therefore there is strong interest in restoring prairies. However, slow‐growing prairie plants are initially weak competitors with the fast‐growing yet short‐lived weedy plant species that are typically abundant in recently established prairie restorations. One way to aid establishment of slow‐growing plant species is through adding soil amendments to prairie restorations before planting. Arbuscular mycorrhizal (AM) fungi form mutualisms with the roots of most terrestrial plants and are particularly important for the growth of slow‐growing prairie plant species. As prairie ecosystems are adapted to fires that leave biochar (charred organic material) in the soil, adding biochar as well as AM fungal strains from undisturbed remnant prairies into the soil of prairie restorations may improve restoration outcomes. Here, we test this prediction during the first four growing seasons of a prairie restoration. When prairie plant seedlings were inoculated prior to planting into the field with AM fungi derived from remnant prairies, that one‐time inoculation significantly increased growth of five of the nine tested plant species through at least two growing seasons. This long‐term benefit of AM fungal inoculation was unaffected by biochar addition to the soil. Biochar application rates of at least 10 tons/ha significantly decreased Coreopsis tripteris growth but acted synergistically with AM fungal inoculation to significantly improve survival of Schizachyrium scoparium. Overall, inoculation with native AM fungi can help promote prairie plant establishment, but concomitant use of biochar soil amendments had relatively little effect.     

Inoculation with remnant prairie soils increased the growth of three native prairie legumes but not necessarily their associations with beneficial soil microbes

Restoring the diversity of plant species found in remnant communities is a challenge for restoration practitioners, in part because many reintroduced plant species fail to establish in restored sites. Legumes establish particularly poorly, perhaps because they depend on two guilds of soil microbial mutualists, rhizobial bacteria and arbuscular mycorrhizal (AM) fungi, that may be absent from restored sites. We tested the effect of soil microorganisms from remnant and restored prairies on legume growth by inoculating seedlings of Lespedeza capitata, Amorpha canescens, and Dalea purpurea with soil from 10 restored prairies and 6 remnant (untilled) prairies from southwest Michigan. We generally found support for the hypothesis that restored prairie soils lack microbes that enhance prairie plant growth, although there was variation across species and mutualist guilds. All three legumes grew larger and two legumes (Lespedeza and Amorpha) produced more nodules when inoculated with soil from remnant prairies, suggesting that low quantity and/or quality of rhizobial partners may limit the establishment of those species in restored prairies. In contrast, no legume experienced greater root colonization by AM fungi in remnant prairie soils, suggesting equivalent quantity (but not necessarily quality) of fungal partners in remnant and restored prairie soils. We detected no evidence of spontaneous recovery of the community of beneficial soil microbes in restorations. These results suggest that the absence of rhizobia, a largely overlooked component of prairie soils, could play a strong role in limiting restored prairie diversity by hindering legume establishment. Active reintroduction of appropriate rhizobial strains could enhance prairie restoration outcomes.     

Mycorrhizal suppression alters plant productivity and forb establishment in a grass-dominated prairie restoration

A fundamental goal of restoration is the re-establishment of plant diversity representative of native vegetation. However, many prairie restorations or Conservation Reserve Program sites have been seeded with warm-season grasses, leading to grass-dominated, low-diversity restorations not representative of native grasslands. These dominant grasses are strongly mycotrophic, while many subordinate forb species appear to be less dependent on mycorrhizal symbiosis. Therefore, manipulating arbuscular mycorrhizal fungi (AMF) may be useful in promoting establishment and growth of forb species in grass-dominated prairie restorations. To assess the potential role of mycorrhizae in affecting the productivity and community composition of restored tallgrass prairie, we conducted a 4-year field experiment on an 8-year-old grassland restoration at the Konza Prairie in northeastern Kansas, USA. At the initiation of our study, seeds of 12 forb species varying in degree of mycorrhizal dependence were added to established grass-dominated plots. Replicate plots were treated bi-weekly with a soil drench of fungicide (Topsin-M^®) over four growing seasons and compared to non-treated control plots to assess the role of AMF in affecting plant species composition, productivity, leaf tissue quality, and diversity in restored tallgrass prairie. Topsin applications successfully reduced mycorrhizal colonization of grass roots to approximately 60–80% relative to roots in control plots. Four years of mycorrhizal suppression reduced productivity of the dominant grasses and increased plant species richness and diversity. These results highlight the importance of mycorrhizae as mediators of plant productivity and community dynamics in restored tallgrass prairie and indicate that temporarily suppressing AMF decreases productivity of the dominant C4 grasses and allows for establishment of seeded forb species.     

Ecological Assessment of Dune Restorations in the Great Lakes Region

Because of the economic and environmental importance of stabilizing fragile sand dune habitats, restoration of dunes has become a common practice. Restoration efforts in the Great Lakes and East Coast regions of North America often consist of planting monocultures of the dominant native grass species, Ammophila breviligulata. We evaluated 18 dune restoration projects in the Great Lakes region conducted over the past 25 years. We characterized attributes of diversity (plants and insects), vegetation structure (plant biomass and cover), and ecological processes (soil nutrients and mycorrhizal fungi abundance) in each restoration, and we compared these measures to geographically paired natural dune communities. Restoration sites were similar to reference sites in most measured variables. Differences between restorations and reference sites were mostly explained by differences in ages, with the younger sites supporting slightly lower plant diversity and mycorrhizal spore abundance than older sites. Plant community composition varied little between restored and reference sites, with only one native forb species, Artemisia campestris, occurring significantly more often in reference sites than restored sites. Although it remains unclear whether more diverse restoration plantings could accelerate convergence on the ecological conditions of reference dunes, in general, traditional restoration efforts involving monoculture plantings of A. breviligulata in Great Lakes sand dunes appear to achieve ecological conditions found in reference dunes.     

Are Ericoid Mycorrhizas a Factor in the Success of Calluna vulgaris Heathland Restoration?

Methods used in the restoration of lowland heath vary depending on edaphic factors at a site and need for introduction of ericaceous propagules. This study investigates the effect of some methods on growth of an important ericaceous species, Heather (Calluna vulgaris). It also explores whether success of growth of C. vulgaris in restoration schemes is affected by its degree of colonization by ericoid mycorrhizal fungi (ERM). The success of Heather growth was compared at three sites, a control area of natural heathland and two restoration sites. These were a quarry where soil had been translocated but not chemically manipulated and a site on agricultural land where the top soil had been improved but then either stripped away or acidified prior to attempting heathland restoration. Propagules of C. vulgaris were applied either as turves or as clippings. Results show that clippings produced as dense a cover of C. vulgaris as turves over a period of 13 years and that plants in such swards can exhibit a degree of ERM colonization comparable to that found in mature plants growing in natural heathland. Young (<2 years of age) plants of C. vulgaris had less extensive mycorrhizal colonization of their roots, particularly when growing on restored agricultural soils. A relationship was found between lower levels of mycorrhizal colonization and smaller aboveground plant growth. Success of heathland restoration may be improved by finding means to enhance the rate and extent of mycorrhizal colonization of young C. vulgaris growing in a restoration environment.     

Soil microbial communities in restored and unrestored coastal dune ecosystems in California

Most restoration projects involving invasive plant eradication tend to focus on plant removal with little consideration given to how these invasives change soil microbial communities. However, soil microorganisms can determine invasibility of habitats and, in turn, be altered by invasives once established, potentially inhibiting native plant establishment. We studied soil microbial communities in coastal dunes with varying invasion intensity and different restoration approaches (herbicide, mechanical excavation) at Point Reyes National Seashore. Overall, we found evidence of a strong link between bacterial and fungal soil communities and the presence of invasives and restoration approach. Heavily invaded sites were characterized by a lower abundance of putatively identified nitrifiers, fermentative bacteria, fungal parasites, and fungal dung saprotrophs and a higher abundance of cellulolytic bacteria and a class of arbuscular mycorrhizal fungi (Archaeosporomycetes). Changes in soil microbiota did not fully dissipate following removal of invasives using herbicide, with exception of reductions in cellulolytic bacteria and Archaeosporomycetes abundance. Mechanical restoration effectively removed both invasives and soil legacy effects by inverting or “flipping” rhizome‐contaminated surface soils with soils from below and may have inadvertently induced other adverse effects on soils that impeded reestablishment of native dune plants. Land managers should consider additional measures to counteract lingering legacy effects and/or focus restoration efforts in areas where legacy effects are less pronounced.     

Open‐cut mining impacts on soil abiotic and bacterial community properties as shown by restoration chronosequence

Open‐cut mining severely disrupts landforms and soils, preventing or impeding the restoration of preexisting or functional ecosystems because essential properties of the original soils cannot immediately or easily be reinstated. We examined the soil physicochemical and bacterial characteristics of 21 coal‐mined sites in subtropical Queensland, Australia, 3–23 years after establishment of native plant species relative to nonmined analogue sites. Soil disturbance significantly decreased total nitrogen, nitrate nitrogen, and especially total carbon (TC). The TC is projected to take 36 years to recover. Bacterial communities assessed by 16S ribosomal RNA sequencing showed greater species richness and evenness in rehabilitated as compared with nonmined soils, regardless of rehabilitation age. However, bacterial species composition was associated significantly with soil electrical conductivity, the plant density, and total stem cross‐sectional area of woody vegetation. The bacterial communities on rehabilitated sites became progressively more similar to those of nonmined analogue sites over time. This work demonstrates that if topsoils are conserved carefully during mining and supplemented by inorganic fertilizer addition, vigorous plant growth and changes in bacterial community composition can occur soon after plant establishment. This will mitigate the effects of soil disturbance and accelerate the return to the chemical and biological attributes of nonmined analogue soils.     

Management of Indigenous Plant-Microbe Symbioses Aids Restoration of Desertified Ecosystems

Disturbance of natural plant communities is the first visible indication of a desertification process, but damage to physical, chemical, and biological soil properties is known to occur simultaneously. Such soil degradation limits reestablishment of the natural plant cover. In particular, desertification causes disturbance of plant-microbe symbioses which are a critical ecological factor in helping further plant growth in degraded ecosystems. Here we demonstrate, in two long-term experiments in a desertified Mediterranean ecosystem, that inoculation with indigenous arbuscular mycorrhizal fungi and with rhizobial nitrogen-fixing bacteria not only enhanced the establishment of key plant species but also increased soil fertility and quality. The dual symbiosis increased the soil nitrogen (N) content, organic matter, and hydrostable soil aggregates and enhanced N transfer from N-fixing to nonfixing species associated within the natural succession. We conclude that the introduction of target indigenous species of plants associated with a managed community of microbial symbionts is a successful biotechnological tool to aid the recovery of desertified ecosystems.     

Disturbance is more important than seeding or grazing in determining soil microbial communities in a semiarid grassland

A primary goal of ecological restoration is often to return processes and functions to degraded ecosystems. Soil, while often ignored in restoration, supports diverse communities of organisms and is a fundamental actor in providing ecosystem processes and services. We investigated the impact of seeding and livestock grazing on plant communities, soil microorganisms, and soil fertility 3 years after the restoration of a disturbed pipeline corridor in southeastern Arizona. The initial soil disturbance and topsoil treatment, regardless of seeding or grazing, was the most influential factor in determining differences in both plant and microbial communities. Compared with the control, the disturbed and restored sites had greater plant species richness, greater total herbaceous plant cover, greater soil organic matter, higher pH, and differed in soil nutrients. Bacteria and fungi appeared to generally correlate with micro‐environment and soil physiochemical properties rather than specific plant species. The undisturbed control had a smaller proportion of bacterial functional groups associated with the breakdown of plant biomass (polysaccharide decomposition) and a smaller proportion of arbuscular mycorrhizal fungi (AMF) compared with disturbed and restored sites. The ability of the unseeded disturbed site to recover robust vegetation may be due in part to the high presence of AMF. These differences show selection for soil microorganisms that thrive in disturbed and restored sites and may contribute to increased plant productivity. Restoration of specific plant species or ecological processes and services would both benefit from better understanding of the impacts of disturbance on soil microorganisms and soil fertility.     

Soil pH influences patterns of plant community composition after restoration with native‐based seed mixes

Reclamation of highly disturbed lands typically includes establishing fast‐growing, non‐native plants to achieve rapid ground cover for erosion control. Establishing native plant communities could achieve ecosystem functions beyond soil erosion, such as providing wildlife habitat. Pipelines, or other disturbed corridors through a landscape, present unique challenges for establishing native plant communities given the heterogeneity of soil environments and invasive plant propagule pressure. We created two structural equation models to address multiple related hypotheses about the influence of soil pH on plant community composition (current diversity and vegetative cover of the original restoration seed mix and background flora, and invasive plant density during mix establishment and current density) of a highly disturbed landscape corridor restored with native species. To test our hypotheses we conducted a plant survey on a gas pipeline crossing two state forests in the north‐central Appalachians that had been seeded with a native‐based mixture 8 years prior. Low soil pH was a strong predictor of density of the invasive annual plant, Microstegium vimineum, and had resulted in lower species diversity and cover of the seeded mix. Overall, our data provide evidence that native‐based grass and forb mixtures can establish and persist on a wide range of soil environments and thrive in competition with invasive plants in moderately acidic to neutral soils. Advancing knowledge on restoration methods using native species is essential to improving restoration practice norms to incorporate multifunctional ecological goals.     

青藏高原高寒草地AM真菌分布及其对近自然恢复的生态作用

超载过牧以及全球气候变化等导致大部分青藏高原高寒草地呈现持续退化态势。青藏高原高寒草地退化致使地上植物群落逐渐发生更替,地下土壤微生物群落多样性和丰富度发生改变。本文旨在探析青藏高原高寒草地丛枝菌根（arbuscular mycorrhizal,AM）真菌的分布特征、对近自然恢复的生理生态效应及其作用机制。青藏高原高寒草地中已报道4目14属61种AM真菌,约占已知AM真菌物种的20%。高寒草地禾本科植物根围AM真菌物种丰度最高,而莎草科植物根围AM真菌孢子密度最高。3种高寒草地植被类型中,高寒草原AM真菌丰度最高（33种）,山地灌丛草原次之（32种）,高寒草甸最低（22种）。高寒草原以光壁无梗囊霉Acaulospora laevis和闪亮和平囊霉Pacispora scintillans为优势种,山地灌丛草原以摩西斗管囊霉Funneliformis mosseae为优势种,高寒草甸以光壁无梗囊霉A. laevis、近明球囊霉Claroideoglomus claroideum和闪亮和平囊霉P. scintillans为优势种。高寒草地土著AM真菌与植物构建的菌根网络可以通过调节营养元素吸收、分配,促进植物建植和生长;但是毒杂草入侵可以改变土著AM真菌物种多样性和菌根网络,限制本地植被的实际生态位扩张。退化高寒草地中,AM真菌群落具有高的环境适应性和恢复力,其不仅调控地上植物群落建植和多样性,同时AM真菌建植也增加了代谢产物-球囊霉素相关土壤蛋白产生,进而协同改善地下土壤微生态系统,为退化高寒草地早期植被恢复塑造土壤生境。因此,AM真菌在退化高寒草地近自然恢复中具有较大的应用潜力。     

大保高速公路老营段路域植被生态恢复

路域植被生态系统的恢复与重建不仅是道路生态学的重要研究内容,而且也是恢复生态学的重要研究领域.以大保高速公路老营段路域植被生态系统为对象,对比分析了8种植被恢复模式的作用效果与作用机理.研究结果表明,在相同的恢复时间内,自然恢复的植物群落中本土植物的比例相对较高,自然恢复是该区路域植被恢复的理想模式之一.随着恢复演替时间的推移,所有群落中木本植物的比例不断增加,草本植物的比例不断下降,植物群落分层现象明显,植物群落向原生植被发生进展或偏途演替.补播本土植物是促进植被恢复演替进程的主要途径之一,不仅可以增加乡土物种的比例、增加植物群落的多样性和均匀度,而且随着恢复时间的推移,可以形成层次明显、功能群组合合理的植物群落.人工蓝桉经济林不仅降低了植物群落及各功能群的多样性、丰富度和均匀度,而且在一定程度上增加了潜在生态风险.研究结果还表明,植物群落中当地物种的比例、植物群落的物种多样性和植物群落的盖度可以作为植被恢复成功与否的重要判定指标.     

Inoculation with native soil improves seedling survival and reduces non-native reinvasion in a grassland restoration

Losses of grasslands have been largely attributed to widespread land-use changes, such as conversion to row-crop agriculture. The remaining tallgrass prairie faces further losses due to biological invasions by non-native plant species, often with resultant ecosystem degradation. Of critical concern for conservation, restoration of native grasslands has been met with little success following eradication of non-native plants. In addition to the direct and indirect effects of non-native invasive plants on beneficial soil microbes, management practices targeting invasive species may also negatively affect subsequent restoration efforts. To assess mechanisms limiting germination and survival of native species and to improve native species establishment, we established six replicate plots of each of the following four treatments: (1) inoculated with freshly collected prairie soil with native seeds; (2) inoculated with steam-pasteurized soil with native seeds; (3) noninoculated with native seeds; or (4) noninoculated/nonseeded control. Inoculation with whole soil did not improve seed germination; however, addition of whole soil significantly improved native species survival, compared to pasteurized soil or noninoculated treatments. Inoculation with whole soil significantly decreased reestablishment of non-native invasive Bothriochloa bladhii (Caucasian bluestem); at the end of the growing season, plots receiving whole soil consisted of approximately 30% B. bladhii cover, compared to approximately 80% in plots receiving no soil inoculum. Our results suggest invasion and eradication efforts negatively affect arbuscular mycorrhizal hyphal and spore abundances and soil aggregate stability, and inoculation with locally adapted soil microbial communities can improve metrics of restoration success, including plant species richness and diversity, while decreasing reinvasion by non-native species.     

Animal Colonization of Restored Peatlands: Inoculation of Plant Material as a Source of Insects

Ecological restoration of mined peatlands in North America involves active reintroduction of bog plant species. Animals are not actively reintroduced, thus the re‐establishment of peatland fauna must occur either by inoculation along with introduced plant material or by dispersal. We examined the extent to which insects are reintroduced to restored sites with plant material by rearing insects from shredded vegetation collected in three donor sites. We assessed differences in abundance, diversity, and composition of taxonomic and trophic groups among seasons and sites. Abundance and species richness did not differ by season, but species assemblages did. The three sites were significantly different in abundance, but not in species richness and assemblages. Few insects emerged from the vegetation, suggesting that shredded plant material may not be the primary source of insect colonists. Insects likely recolonize by active or passive dispersal from the surrounding area. The species pool was similar among donor sites; consequently a mined site could be inoculated with vegetation from another peatland in the same region and this would not affect the insect assemblages at the initial stage of establishment. Diapause may be a major factor for emergence success among seasons of collection. Knowledge of how restoration techniques influence establishment of insect communities will help predict longer‐term outcomes of restoration on biotic communities in peatlands.     

A meta-analysis of arbuscular mycorrhizal effects on plants grown under salt stress

Salt stress limits crop yield and sustainable agriculture in most arid and semiarid regions of the world. Arbuscular mycorrhizal fungi (AMF) are considered bio-ameliorators of soil salinity tolerance in plants. In evaluating AMF as significant predictors of mycorrhizal ecology, precise quantifiable changes in plant biomass and nutrient uptake under salt stress are crucial factors. Therefore, the objective of the present study was to analyze the magnitude of the effects of AMF inoculation on growth and nutrient uptake of plants under salt stress through meta-analyses. For this, data were compared in the context of mycorrhizal host plant species, plant family and functional group, herbaceous vs. woody plants, annual vs. perennial plants, and the level of salinity across 43 studies. Results indicate that, under saline conditions, AMF inoculation significantly increased total, shoot, and root biomass as well as phosphorous (P), nitrogen (N), and potassium (K) uptake. Activities of the antioxidant enzymes superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase also increased significantly in mycorrhizal compared to nonmycorrhizal plants growing under salt stress. In addition, sodium (Na) uptake decreased significantly in mycorrhizal plants, while changes in proline accumulation were not significant. Across most subsets of the data analysis, identities of AMF (Glomus fasciculatum) and host plants (Acacia nilotica, herbs, woody and perennial) were found to be essential in understanding plant responses to salinity stress. For the analyzed dataset, it is concluded that under salt stress, mycorrhizal plants have extensive root traits and mycorrhizal morphological traits which help the uptake of more P and K, together with the enhanced production of antioxidant enzymes resulting in salt stress alleviation and increased plant biomass.     

Deploying microbes as drivers and indicators in ecological restoration

Ecosystem degradation is a major environmental threat. Beyond conservation, restoration of degraded ecosystems is a prerequisite to reinstate their ability to provide essential services and benefits. Most of the restoration efforts focus on aboveground restoration, that is, plants, under the assumption that establishment of plant species will reestablish the faunal and microbial species. While this may be true for some cases, it is not a general rule. Reestablishment of microbial communities by dedicated efforts is also necessary for successful restoration, as cycling of essential nutrients for plant growth and decomposition of organic matter is dependent on them. The role of microbial fertilizers and efficient organisms used in agriculture needs to be explored in restoration. Testing of symbiotic interactions between potential plant growth-promoting Rhizobacteria and plants native to a degraded ecosystem can be conducted and utilized for successful establishment of plant species. However, utmost care must be taken while introducing new microbial species or non-native plant species to an area, as they can adversely affect the resident microbial community. Techniques like phospholipid fatty-acid analysis can be used for taxonomic identification of large microbial groups in non-degraded reference ecosystems before introducing microbial species into a degraded ecosystem. For use of microbes in restoration, more studies on microbe-plant interactions need to be conducted. For use of Soil Microbial Community (SMC) as indicators of restoration, their role and function in the ecology of the area need to be elucidated by employing all the available techniques.     

The effects of arbuscular mycorrhizal fungal inoculation at a roadside prairie restoration site

Arbuscular mycorrhizal fungi (AMF) may play an important role in ecological succession, but few studies have documented the effectiveness of mycorrhizal inoculation at restoration/reclamation sites. At a roadside prairie restoration in Shakopee, Minnesota, we compared AMF root colonization and resulting vegetative cover among four inoculation treatments. After 15 mo of growth, we found that AMF colonization was high in all treatments but was significantly higher in treatments that received AMF inoculum propagated from a local prairie site or commercially available inoculum than the uninoculated control. For the prairie inoculum, this increase in colonization occurred whether the inoculum was applied with seeds in furrows or broadcast with seeds on the soil surface. However, increased colonization did not discernibly affect the restored vegetation; neither total vegetative cover nor the proportion "desired" prairie vegetation differed among inoculation treatments. By the end of the third growing season (27 mo after planting) there were no longer differences in AMF colonization among the inoculation treatments nor were there differences in vegetative cover. It is likely that natural recolonization of the plots by remnant AMF populations at the site limited the duration of the inoculation effect. This natural recolonization, in combination with relatively high soil phosphorus levels, likely rendered inoculation unnecessary. In contrast to previous published studies of AMF inoculation in landscape restorations, this study shows that AMF inoculation may not be warranted under some circumstances.