Establishment of a Vegetation Cover on Tundra Kimberlite Mine Tailings: 2. A Field Study

High erosion potential of dewatered kimberlite mine tailings after diamond extraction has prompted research at the Ekati Diamond Mine in the Canadian subarctic heath tundra ecosystem. Greenhouse and field studies aimed at establishing a permanent vegetation cover on these dewatered tailings began in spring 2000. Coarse texture, no organic component, lack of available macronutrients, and a serpentine chemistry are the principal limitations of kimberlite tailings to plant colonization. Structure‐improving (peat moss, lake sediment, and sewage sludge) and nutrient‐providing (fertilizer, rock phosphate, calcium carbonate, and gypsum) amendments were tested to ameliorate these conditions, facilitating the establishment of a permanent vegetation cover, which stabilizes surface materials and promotes natural colonization by the surrounding tundra vegetation. Seven native grass species (Arctagrostis latifolia, Calamagrostis canadensis, Poa glauca, Poa alpina, Deschampsia beringensis, Deschampsia caespitosa, and Festuca rubra) were used to measure amendment success. With the addition of structure‐improving and nutrient‐providing amendments, plant growth on these kimberlite tailings under field conditions was significantly improved over unamended tailings material. Tailings properties, including cation exchange capacity, organic carbon, and macronutrient availability, were also improved with amendment addition.     

Establishment of a Vegetation Cover on Tundra Kimberlite Mine Tailings: 1. A Greenhouse Study

High erosion potential of dewatered kimberlite mine tailings after diamond extraction has prompted research at the Ekati Diamond Mine in the Canadian subarctic heath tundra ecosystem. Coarse texture, no organic component, lack of available macronutrients, and a serpentine chemistry are the principal limitations of these kimberlite tailings to plant colonization. Structure‐improving (peat moss, lake sediment, sewage sludge, Agri‐Boost, and composted papermill sludge) and nutrient‐providing (fertilizer, calcium carbonate, gypsum, and rock phosphate) amendments were tested in the greenhouse to ameliorate these limitations, thereby facilitating the field establishment of a permanent vegetation cover, which would stabilize the surface materials and promote natural colonization by the surrounding tundra vegetation. Seven native grass species (Arctagrostis latifolia, Calamagrostis canadensis, Poa glauca, Poa alpina, Deschampsia beringensis, Deschampsia caespitosa, and Festuca rubra) were used to measure amendment success. With the addition of structure‐improving and nutrient‐providing amendments, plant growth on kimberlite tailings was significantly enhanced. Tailings properties, including cation exchange capacity, percentage of organic carbon, and macronutrient availability, were also improved by amendment addition.     

Studies on the Host Range,Biology, and Pathogenicity of Punctodera punctata Infecting Turfgrasses

Punctodera punctata completed its life cycle on Poa annua (annual bluegrass), P. pratensis (Merion Kentucky bluegrass), Lolium perenne (perennial ryegrass), and Festuca rubra rubra (spreading fescue). Minimum time for completion of a life cycle from second-stage juvenile to mature brown cyst was 40 days at 22-28 C. Inoculation by single juveniles indicated that reproduction was most likely by amphimixis. Infestation levels of 50 or 500 juveniles/250 cm³ soil did not affect top dry weight, root dry weight, or total dry weight of Poa annua.     

Thermal Dependence of the Apparent Kmof Glutathione Reductase from Three Wetland Grasses and Maize

The thermal dependence of enzyme kinetic parameters has beenpresented as an indicator of species’ thermal optima andtolerance limits. Previous studies suggest the relationshipbetween temperature and the apparent Michaelis–Mentenconstant (K_m) of an enzyme system can be used to predict wholeplant success at specific temperatures. The apparent K_mfor glutathionereductase (EC 1.6.4.2; GR) (oxidized glutathione as substrate)extracted from leaves of American sloughgrass (Beckmannia syzigachneSteud.), tufted hairgrass (Deschampsia caespitosa L.), tallfescue (Festuca arundinaceae Schreb. ‘Titan’), andmaize (Zea mays L.), was determined over a range of temperatures(1–40 °C). For all species, minimum apparent K_mforGR was observed at 1 °C, and K_mvalues increased as temperatureincreased. The apparent K_mvalues differed among all speciesat the lower temperatures (1–15 °C), but were similarat higher temperatures. The enzyme from tufted hairgrass hadthe lowest apparent K_mat low temperatures (<15 °C), followedin increasing order by American sloughgrass, tall fescue andmaize. Our experimental system failed to reproduce thermal kineticwindow profiles similar to those reported elsewhere. With respectto the enzyme systems reported here, results suggest that thesecool-season grasses can be ranked as more to less eurythermicwithin the temperature range from 1 to 15 °C. Copyright0000 American sloughgrass, Beckmannia syzigachne Steud., tufted hairgrass, Deschampsia caespitosa L., tall fescue, Festuca arundinaceae Schreb. ‘Titan’, Zea mays L., plant competition, temperature stress, kinetics, Michaelis–Menten constant (K_m), glutathione reductase     

Effects on vegetative restoration of two treatments: erosion matting and supplemental rock cover in the alpine ecosystem

Unsanctioned travel routes through alpine ecosystems can influence water drainage patterns, cause sedimentation of streams, and erode soils. These disturbed areas can take decades to revegetate. In 2012, a volunteer‐driven project restored a 854‐m section of unsanctioned road along the Continental Divide in Colorado, United States. The restored area was seeded with three native grass species and then treated by installing erosion matting or adding supplemental rock cover. Four years later, results suggest that the seeding along with the use of erosion matting or supplemental rock can enhance revegetation. Matting appeared to accumulate litter, and this effect might have contributed to enhanced moisture retention. Treated areas contained 40% of the vegetation cover found on adjacent controls, which averaged 69% vascular plant absolute cover. Recovery on both treatments was markedly higher than published estimates of passive revegetation of disturbed areas measured elsewhere suggesting seeding with added cover or protection led to substantial vegetative cover after 4 years. Two of the 3 seeded grass species, Trisetum spicatum and Poa alpina, dominated the restored plots, composing 81.7% of relative vegetation cover on matting sites and 73.4% of relative cover on rock‐supplemented areas. Presumably due to its preference for moister sites, Deschampsia cespitosa had low establishment rates. Volunteer species, that is species that appeared on their own, contributed 6.3% to the absolute vegetation cover of matting and rock sites, and species such as Minuartia biflora, Minuartia obtusiloba, Poa glauca, and Festuca brachyphylla should be considered for use in future restorations.     

<Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated transformation of shoot apices of Kentucky bluegrass (<Emphasis Type="Italic">Poa pratensis</Emphasis> L.) and production of transgenic plants carrying a <Emphasis Type="Italic">betA</Emphasis> gene

Apical meristems of multiple shoots produced from axenic seedlings of Kentucky bluegrass (Poa pratensis L.) were used for Agrobacterium tumefaciens-mediated transformation. Transformation parameters were optimized for concentration of bacterial cells, duration of infection, and vacuum infiltration. The highest transformation frequency (1.42%) was obtained by infection with Agrobacterium suspension of OD₆₀₀ = 0.6 for 5 min, under a negative pressure of 0.5 × 10⁵ Pa. After co-cultivation, the herbicide-resistant plants were rooted and transplanted into flowerpots. Transgenic plants were confirmed by polymerase chain reaction (PCR) assay and Southern blot analysis. Using this transformation system, the betA gene encoding choline dehydrogenase and mutant als gene encoding the enzyme acetolactate synthase were introduced into three Kentucky bluegrass cultivars.     

Vegetation changes following sheep grazing in abandoned mountain meadows

Abstract. Sheep grazing was investigated as an alternative to traditional management of meadows in the Krkono?e Mts. Until the second World War these meadows were mown in mid‐summer and grazed by cattle for the rest of the season. Subsequent abandonment of the meadows has resulted in decreasing species richness. Degradation phases of the former communities have been replacing the original species‐rich vegetation. Significant changes were apparent six years after the introduction of sheep grazing. In grazed plots the proportion of dominant herbs (Polygonum bistorta and Hypericum maculatum) decreased and grasses (Deschampsia cespitosa, Festuca rubra, Agrostis capillaris, Anthoxanthum alpinum) increased. The increase in grasses was positively correlated with an increase in several herbs. The proportion of some herbs increased despite being selectively grazed (Adenostyles alliariae, Melandrium rubrum, Veratrum lobelianum). Any losses caused by grazing of mature plants were probably compensated by successful seedling establishment. Cessation of grazing resulted in significant changes in vegetation within three years. The cover of nitrophilous tall herbs and grasses (e.g. Rumex alpestris, Holcus mollis, Deschampsia cespitosa, Geranium sylvaticum) increased in the abandoned plots. In the plots grazed for nine years cover of species‐rich mountain meadow species increased (e.g. fine‐leaved grasses, Campanula bohemica, Potentilla aurea, Viola lutea, Silene vulgaris). The main conservation risk is the expansion of a competitive species with low palatability, Deschampsia cespitosa. This species can be suppressed by a combination of grazing and mowing. In order for grazing to be effective, the number of sheep should be proportional to meadow production. This may be difficult to maintain as production is variable and is impossible to predict at the beginning of a growing season. A large part of the biomass may thus remain intact in some years. Negative effects of grazing may be, at least partly, eliminated by a combination of cutting and grazing.     

Effects of temperature, light, nitrate and pre chilling on seed germination of grassland plants

The effects of factorial combinations of alternating (20/10 ^oC) and constant temperature (20 ^oC), of light (intermittent) and dark, and of distilled water and nitrate on the germination of a range of species of indigenous grassland were investigated in 1979, and in 1980 when the effects of pre-chilling were also studied. Species differed greatly in their response to the eight sets of environmental conditions in 1979. With the exception of Lolium perenne ssp. perenne and Cynosurus cristatus, only a small percentage of seeds of most species was able to germinate in constant temperature in the dark. However, when light was supplied there was moderate germination of Anthoxanthum odoratum, Cerastium fontanum ssp. glabrescens, Festuca rubra, Holcus lanatus and Poa trivialis. Alternating temperature greatly increased the germination of most species and nitrate further increased germination of Agrostis capillaris, Deschampsia caespitosa, H. lanatus, Poa annua and P. trivialis. In alternating temperatures, light increased germination of these species even more than did nitrate. A. capillaris, D. caespitosa and P. annua required all three factors for maximum germination, and another 7% of seeds of A. capillaris also required gibberellic acid. Germination responses following sequential application of factors often differed from those resulting from simultaneous treatment: in particular, the germination of Ranunculus species was greatly enhanced. Although seeds of the species tested in 1980 were more germinable than those of the same species in 1979, they responded similarly to the different factors. Light increased the germination of both Taraxacum officinale and Plantago lanceolata in constant but not in alternating temperature, while nitrate was much more stimulatory to the latter species. About half the seeds of P. lanceolata were dormant. Pre-chilling at 4^oC for 7 days increased subsequent germination of all species when followed by constant temperature, except of A. capillaris in the dark and C. cristatus (already maximal) in the light. When followed by alternating temperature in the dark, pre-chilling greatly decreased germination of A. capillaris. In the light, where germination of most species was maximal, there was little effect of pre-chilling. Longer durations (21 and 42 days) of chilling of older seed gave similar results to the 7 day pre-chilling.     

Flowering Competence after Exposure to Naturally Fluctuating Winter Temperatures in a Perennial Grass, Deschampsia caespitosa (L.) Beauv

Tussocks of three clones of the perennial grass Deschampsiacaespitosa were exposed to natural temperatures, for successiveperiods with increments of one week, throughout each seasonin four consecutive autumn/winter seasons. After exposure theywere returned to a warm, illuminated glasshouse and the incidence,intensity and timing of flowering were recorded. The year-to-year variations in exposure time requirement forfull flowering were very highly correlated (r² > 0.98) withmean air temperature in the period between mid-September andearly December. The relationship with the natural logarithmof accumulated air temperature was similarly good. Daily meanair temperature was also demonstrated to be a good indicatorof daily mean tussock temperature (r² = 0.91), in a series ofmeasurements in the autumn of 1976. More prolonged exposure increased the proportion of apices ina tussock which flowered, but the maximum value at the end ofa whole winter was only about 15 per cent. The cumulative vernalizationeffects of naturally fluctuating temperature regimes are analysedand the significance of these findings for the maintenance ofperenniality in clonal grasses is considered. Deschampsia caespitosa (L.) Beauv., tufted hairgrass, flowering, vernalization, temperature, perenniality     

Festuca campestris density and defoliation regulate abundance of the rhizomatous grass Poa pratensis in a fallow field

Invasion by the rhizomatous grass Kentucky bluegrass (Poa pratensis) is a global phenomenon, including into foothills rough fescue (Festuca campestris) grasslands of southwestern Alberta, Canada. In order to better understand the competitive relationships between these species, we conducted a fallow field study where rough fescue bunchgrass tussocks were transplanted at one of three planting densities (15, 30, or 45 cm spacing), and then subject to various treatments in a factorial design, including one‐time intensive summer defoliation and seeding of bluegrass into adjacent bare soil. Rough fescue plants exhibited marked intraspecific competition, as high planting densities increased tussock mortality, while decreasing plant tiller counts and relative inflorescence production, together with plant and tiller‐specific mass. However, high densities of the bunchgrass also reduced the cover and biomass of encroaching bluegrass, coincidental with reduced resource (soil moisture and light) availability in mid‐summer. Although summer defoliation increased rough fescue tiller counts, this disturbance reduced plant and tiller mass, and also increased Kentucky bluegrass. We conclude that while high densities of nondefoliated stands of rough fescue may increase resistance to bluegrass encroachment, a reduction in either fescue plant density or vigor via defoliation can increase the risk of bluegrass invasion within northern temperate grassland.     

Effect of fertilized,unfertilized, and UV‐irradiated hosts on parasitism and suitability for Trichogramma parasitoids

Trichogramma spp. (Hymenoptera: Trichogrammatidae) parasitoids have been commonly used as biological control agents in insect pest management. Host quality is believed to influence parasitism, host preference, and suitability for parasitoids. To date, limited studies have compared the parasitism of Trichogramma parasitoids on fertilized, unfertilized, and sterilized host eggs. Hence, we studied the performance of three Trichogramma egg parasitoids, Trichogramma japonicum Ashmead, Trichogramma chilonis Ishii, and Trichogramma leucaniae Pang & Chen, on fertilized, unfertilized, and ultraviolet (UV)‐irradiated fertilized (UVF) eggs of rice moth, Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae). In a no‐choice test, T. japonicum and T. leucaniae parasitized significantly more fertilized or UVF than unfertilized hosts, and T. chilonis parasitized significantly more UVF than either fertilized or unfertilized hosts. In a choice test, all three Trichogramma parasitoids parasitized UVF hosts the most, and unfertilized hosts the least. There were similar percentages of adult emergence and female progeny among fertilized, unfertilized, and UVF hosts for all three Trichogramma parasitoids, except that T. japonicum had significantly lower adult emergence on fertilized hosts. We also found that all three Trichogramma parasitoids developed slower on unfertilized hosts. Regardless of host treatments, T. leucaniae had the longest developmental time and T. chilonis had the shortest. We conclude that Trichogramma parasitoids prefer parasitizing UVF eggs of C. cephalonica without negative effects on their emergence and sex allocation.     

Germinability and enforced dormancy in seeds of species of indigenous grassland

Germination of seeds of a range of species from indigenous grassland was tested at an alternating temperature regime in incubators, soon after they were shed in 1978 and also after various intervals of dry storage at outdoor ambient temperatures. Concomitant investigations were made of seedling emergence from and seed survival at different depths of soil in pots; Poa annua and Poa trivialis were investigated separately in 1979. Almost all seeds of Lolium perenne, Cynosurus cristatus, Festuca rubra and Holcus lanatus germinated readily, but c. 30% of Deschampsia caespitosa seeds and c. 15% of fresh, early-shed Agrostis capillaris did not germinate until they were also given gibberellic acid. However, more late- than early-shed seed of the latter two species germinated and their seeds became more germinable with increasing length of storage. Of the dicotyledonous species tested, germination of Cerastium fontanum ssp. glabrescens was rapid and complete, but that of Ranunculus spp. was particularly protracted. All Ranunculus repens seeds and a large proportion of Ranunculus acris seeds were highly dormant. Species differed greatly in their ability to emerge from and persist at different depths in pots. The most persistent species after 15 months were R. repens (69%), A. capillaris (39%), Luzula campestris (37%), C. fontanum ssp. glabrescens (30%), P. trivialis (8%), D. caespitosa (7%) and H. lanatus (3%). A mean of 42% of P. annua and 16% of P. trivialis seeds persisted from autumn 1979 until late spring 1980, but pre-imbibing the seeds decreased seed persistence to 12% and 4% respectively. The results are discussed in relation to previously published information on the germination biology of the species and to the different abilities of the species to become part of the soil seed population.     

Effects of soil organic matter and nitrogen supply on competition between Festuca ovina and Deschampsia flexuosa during inland dune succession

We tested the prediction that the successional replacement of plant species during succession on inland sand dunes results from the effects of an increase in nitrogen mineralization on competitive interactions. The growth and competitive strength of Festuca ovina and Deschampsia flexuosa on soil substrates with different amounts of soil organic matter or nitrogen supply were measured. Small tillers of Festuca ovina and Deschampsia flexuosa were grown in monocultures and 1:1-mixtures on soil columns with undisturbed layers of soil organic matter from different successional age. There was (a) no visible soil organic matter, (b) a thin soil organic layer (0.5 cm) and (c) a thicker soil organic layer (6.0 cm) present on the soil columns. The species were also grown on columns with no visible soil organic matter (bare sand) with two different levels of N fertilization to mimic the increased N mineralization in the older successional stages.In monoculture, Festuca produced more biomass on the substrates with a soil organic layer compared to the unfertilized sand substrate. It also produced more biomass on sand substrates with N fertilization. Deschampsia produced more biomass in treatments with a soil organic layer compared to the bare sand treatments, but did not respond to the ammonium-nitrate addition. In competition, Festuca seemed to be the stronger competitor on the unfertilized sand substrate. Festuca was also the better competitor on the N fertilized sand treatments, while on the treatments with a soil organic layer Deschampsia was the winning species. Our results do not support the hypothesis that an increase in N supply is responsible for the replacement of Festuca by Deschampsia that concur with the accumulation of soil organic matter during succession in inland dunes.     

The “Trojan horse” strategy: Seed fungal endophyte symbiosis helps to explain the invasion success of the grass,Poa annua,in Maritime Antarctica

Aim

Poa annua L. (annual bluegrass) is presently the sole invasive vascular plant species to have successfully established in Maritime Antarctica, where it poses a significant conservation threat to native plant species. However, the reasons for its success in the region have yet to be established. Here, we determined whether the invasiveness of P. annua, and its competitiveness with the native Antarctic hairgrass Deschampsia antarctica, is influenced by symbioses formed with seed fungal endophytes, and whether plants derived from seeds from four global regions differ in their performance.

Locations

Four regions (Maritime Antarctica, sub-Antarctica, South America and Europe).

Methods

Endophyte frequency was measured in P. annua seeds collected from the four regions. The germination, survival, biomass accumulation, flowering and competitiveness with D. antarctica of P. annua plants grown from endophyte-uncolonised and uncolonised seeds was determined in the laboratory. The effects of endophytes on P. annua seed germination and survival and seedling osmoprotection were also assessed in the Maritime Antarctic natural environment using locally-sourced seeds.

Results

Endophytes were at least twice as frequent in seeds from Maritime Antarctica than in those from other regions. A higher proportion of endophyte-colonized seeds germinated and survived than did uncolonised seeds, but only when they originated from Maritime Antarctica. Seed endophytes increased the competitiveness of P. annua with D. antarctica, but only for plants grown from Maritime Antarctic seeds. In the field, endophyte-colonized seeds from Maritime Antarctica germinated and survived more frequently than uncolonised seeds, and osmoprotection was higher in seedlings grown from colonized seed.

Main Conclusions

The findings indicate beneficial effects of seed endophytes on invasion-related traits of P. annua, such as survival, germination success and flowering. Together with vegetative and reproductive traits facilitating the colonization process, the seed-fungal endophyte symbiosis can be invoked as an important factor explaining the invasiveness of P. annua in Maritime Antarctica.     

Abandonment of traditionally managed mesic mountain meadows affects plant species composition and diversity

In recent years abandonment of traditional management of mountain grasslands has been observed throughout Central Europe. However, the impact of abandonment on vegetation of mountain grasslands is still unclear. In this study it was hypothesized that the cessation of traditional management of mesic mountain meadows causes changes in their species composition and a decrease in the biodiversity. In total, 260 plots were established in the Sudetes (SW Poland) on meadows with regular annual mowing, meadows with irregular mowing management, and abandoned meadows. Relevés (5 × 5 m) were performed, and the habitat properties were determined using Ellenberg indicator values. The study confirmed the hypothesis that the various ways of extensive management have an influence on species richness. The lowest species richness was observed on the irregularly managed meadows, while higher species numbers were found on the abandoned and regular managed meadows. The majority of patches on abandoned meadows exhibited degradation through the expansion of Solidago gigantea, Solidago canadensis, Lupinus polyphyllus, Heracleum sosnovsky, Calamagrostis epigejos, Deschampsia flexuosa, Festuca rubra and Hypericum maculatum. Meadows subjected to different management practices differed significantly in Ellenberg indicator values. The abandoned meadows had the highest values of the light index (L) and nitrogen availability (N), whereas the highest values of soil moisture (F) were noted on the irregularly managed meadows. The degradation of mountain mesic meadows requires regular mowing management, which stops ecological succession and preserves their high biodiversity.     

The Possible Role of Polyamines to the Recalcitrance of “Kalamata” Olive Leafy Cuttings to Root

The objective of this study was to investigate the role of endogenous polyamines (PAs) (the sum of free plus soluble conjugate plus insoluble bound) on rooting potential of leafy cuttings of an easy, that is,“Arbequina” and a difficult-to-root olive cultivar, that is, “Kalamata”. Subsamples of cuttings were taken for PAs analysis before planting in the mist system and during the early phases of rhizogenesis (EPR). “Arbequina” exhibited higher initial free and total PA content than “Kalamata”. Spermidine (Spd) was the predominant PA observed in both cultivars. A low content of free putrescine (Put) and Spd was found in both cultivars, whereas spermine (Spm) was occasionally detected. “Arbequina” as well as “Kalamata” exhibited the highest free Put and free Spd in summer and Put was the predominant PA among the free PAs. “Arbequina” exhibited the highest individual and total PAs in spring, followed by those in summer and autumn. In contrast, “Kalamata” had the maximum PAs in summer and the lowest in autumn. Changes in the endogenous content of individual and total PAs during the EPR were also observed. Treatment of “Kalamata” cuttings in autumn with both indole-3-butyric acid (IBA) and Put increased rooting compared to IBA alone. Among the PAs administered, Put was the most effective, whereas Spd and Spm failed to promote rooting. PAs, especially in their free form, seem to be involved in the rooting process of olive cuttings; Put application enhanced the rooting response of the difficult-to-root “Kalamata” olive cultivar.     

早熟禾品种间遗传多样性分析

草地早熟禾（Poa pratensis L.）是一种重要的冷季型草坪草,抗逆性强,适应性广,株型低矮,绿色期长,并且在良好的管理条件下,特别适合用作运动场草坪。近几年来在我国的园林绿化和建植运动场中得到了广泛的应用,现在已经引进的品种多达上百种。选用28个随机引物对15个草地早熟禾品种和1个加拿大早熟禾品种进行RAPD分析,25个引物共扩增出218条带,多态条带比率为89.91％。并且对每个品种的几项坪用特性进行了观察。聚类分析结果表明草地早熟禾品种之间的遗传多样性较低, 相似性集中在60.76％～98.52％。加拿大早熟禾的一个品种单成一支,与其他草地早熟禾的品种相似性较低。品种之间的聚类关系与表型特征呈现不完全相关性。     

Beispiele zur nichtsymbiotischen Luftstickstoffbindung in vergrasten Waldböden

Summary Basally wetted sample sods ofCalamagrostis epigeios andAira caespitosa were tested for N ₂ ¹⁵ -fixation. Traces of N¹⁵ were only found in the samples after cutting and removal of the grass shoots followed by inversion of the sods. Using oat seedlings, the positive effect of the rhizosphere on nitrogen fixation was measured in an artificially mixed soil substrate.      

Interactive effects of biochar and an organic dust suppressant for revegetation and erosion control with herbaceous seed mixtures and willow cuttings

Land reclamation efforts on “non‐soil” substrates frequently involve additions of organic material coupled with soil‐stabilizing dust suppressants to control erosion, but formal experiments, particularly of interactive effects, are lacking. We examined the effects of Entac?, a tall oil pitch emulsion, and pyrolyzed wood waste‐derived biochar on early plant establishment, growth, and survivorship, in 2 factorial greenhouse experiments: 1 using a seed mix widely used for roadside erosion control (the grasses Festuca rubra, Poa pratensis, Lolium perenne, and white clover [Trifolium repens]) and 1 using rooted cuttings of sand bar willow (Salix exigua). Biochar additions of 5, 10, and 20 t/ha enhanced biomass of clover by 14–250%, but had no significant effects on grasses. Entac additions inhibited early establishment and growth of both clover and grasses at all biochar treatment levels. Entac plus biochar treatments significantly enhanced survivorship of willows following a drought treatment in a greenhouse trial. In a field trial, Entac treatments had positive effects on willow diameter growth. Collectively, these results suggest that better soil moisture retention is the principal mechanism responsible for enhanced survivorship and growth of planted willows treated with Entac and biochar on sand substrates. Given Entac's inhibitive effects on early establishment of herbaceous species, and the abilities of Entac and biochar in combination to mitigate drought stress, these treatments may be particularly well suited for ecological restoration efforts using planted tree stock on coarse‐textured substrates and where exposure and ingress of non‐native herbaceous species are of concern.     

Factors controlling vegetation change in long-term experiments designed to restore heathland in Breckland,UK

Abstract. This paper describes the vegetation change in an 18-year experiment designed to test a range of control of Pteridium aquilinum (Pteridium) and heathland restoration treatments; cutting, asulam application and Calluna vulgar is seeding, in a range of combinations at Cavenham Heath in Breckland, UK between 1978 and 1996. Vegetation change was recorded in two Phases; in Phase I (1978-1986) species biomass was sampled and in Phase II (1986-1996) cover was measured. Initially, Calluna establishment was good in some treatments, especially where Calluna seed was added and Pteridium was controlled. Other plots developed either a grass-heath flora dominated by Agrostis capillaris, Deschampsia flexuosa, Dicranum scoparium, Festuca ovina and Rumex acetosella or were dominated by clonal species such as Calamagrostis epigejos or Carex arenaria. An unconstrained ordination showed significant vegetation change through time and that several treatments influenced the vegetation, especially those involving asulam application. When variation partitioning with constrained ordination was used a different explanation emerged. In Phase I the most important factors were the management treatments applied, elapsed time and spatial factors, with little overlap. In Phase II, elapsed time became irrelevant because the variation time explained overlapped that which could be explained by other variables. The most important of these were management treatments, spatial effects, weather, the amount of bare ground caused by disturbance and Pteridium litter cover (an index of Pteridium recovery). The implications of these results in interpreting vegetation change are discussed.