Smoke, Mulch, and Seed Broadcasting Effects on Woodland Restoration in Western Australia

Smoke, canopy‐derived mulch, and broadcast seeds were used to maximize the establishment of Banksia woodland species in sand quarries in Western Australia. Smoke, particularly aerosol smoke, had a positive effect on total seedling recruitment. Pre‐mined (woodland) sites showed a 42‐fold increase in total germinants and a 3‐fold increase in the number of species with aerosol smoke application. Post‐mined (restored) sites showed only a 3.6‐fold increase in total germinants and a 1.4‐fold increase in the number of species. Two water‐based smoke chemicals, DC10 (pH 4.5) and SC63 (pH 2.5), increased seedling recruitment at both sites but were not as effective in stimulating recruitment as aerosol smoke. Neither of the chemicals were effective in significantly increasing species richness. Application of aerosol smoke directly to seeds as a pretreatment before broadcasting had no effect on seedling recruitment. Broadcasting of seeds onto restoration sites significantly increased seedling abundance and richness. Application of a single layer of mulch from the canopy vegetation after seed broadcasting gave optimum seedling recruitment. Two layers of mulch significantly reduced recruitment, as did applying mulch before seed broadcasting. For broad‐scale restoration, the application of smoke on newly restored sites would be more effectively achieved using smoke water sprayed over the soil surface. Species that do not recruit from replaced topsoil could be effectively recovered from broadcast seed rather than from mulch.     

Is broad-scale smoke–water application always a useful tool for improving seedling emergence in post-mining restoration? Evidence from jarrah forest restoration in Western Australia

It has been widely advocated that smoke–water application to topsoil can substantially improve restoration success by enhancing seed germination. This is despite few studies having tested the effects of smoke–water on seedling emergence in field-scale restoration trials. Here we report the effects of applying a commercially available smoke solution (Regen 2000®), at rates between 0 and 100 mL m^− 2, on jarrah forest sites being restored after bauxite mining in the southwest of Western Australia. Smoke solutions stimulated the seed germination of a range of species in laboratory experiments. In addition, smoke–water stimulated germination of Stylidium affine seeds sown directly into the first field experiment. However, apart from the effect on sown S. affine seeds, smoke–water application had no effect on subsequent seedling numbers, species richness or the relative proportion of seedlings in different growth-form categories in either of the two field experiments. These findings suggest that smoke–water application does not always ensure enhanced restoration outcomes.     

Smoke and heat effects on soil seed bank germination for the re‐establishment of a native forest community in New South Wales

The effects of plant‐derived smoke and of heat on the emergence of seedlings from seeds were assessed. Seeds had been stored in forest topsoil used for mine site rehabilitation. The study was carried out in a dry sclerophyll, spotted gum (Corymbia maculata), forest community at the Mount Owen open‐cut coal mine in the Hunter Valley region of New South Wales. Samples of the surface 2.5 cm of topsoil were either exposed to cool smoke from eucalypt foliage for 60 min, heated to 80°C, or left untreated. Seedling emergence from the seed bank in this soil was then monitored in a glasshouse. Within the first month, smoke alone promoted a 4.3‐fold increase in the density of seedlings relative to control. There were 540 emergents per m² in the control and 2309 per m² in the smoke treated topsoil. Many annual and perennial herbs emerged but grasses responded most strongly to smoke. Germination in seven of the 20 grass species was promoted by smoke. Smoke promoted the germination of some introduced species as well as native species, and accelerated the rate at which seedlings emerged, although these differences sometimes declined with time. Heat also stimulated germination but smoke and heat stimuli appeared to be complementary in their promotion of seedling emergence from the topsoil seed bank. Each treatment increased the density of different species, enhanced the species richness of different components of the seed bank, and had different effects on the rate of emergence. The results suggest that increased seed germination in the field immediately following a moderate intensity fire may sometimes be the result of smoke stimulation and sometimes the result of heat stimulation of the soil seed bank. These findings may have important implications for minesite revegetation programs where topsoils are replaced after mining and rapid germination of seeds stored in these soils is required during short periods when conditions are favourable for germination.     

Influence of fire on critically endangered Swartland Shale Renosterveld in the Cape Floristic Region

Questions

The degree to which renosterveld shrublands are fire‐dependent is currently unclear. To address this issue, the following questions were asked: (1) does smoke stimulate germination of soil‐stored seeds in renosterveld; (2) does recently‐burned renosterveld display changed composition and higher diversity than unburned vegetation; and (3) how do the species compositions of renosterveld soil seed banks and standing vegetation compare?

Location

Swartland, Cape Floristic Region, South Africa.

Methods

Soil seed bank samples from a north‐ and south‐facing slope were smoke‐treated and germinated to test for smoke‐stimulated germination. Burned standing vegetation was surveyed 16 months post‐fire, as was unburned vegetation on the same slopes. Seed bank species richness and density were compared between smoke‐treated and untreated samples within and between slopes. Burned and unburned standing vegetation were compared within and between slopes in terms of species richness, abundance and aerial cover. Compositional similarity of the seed banks and standing vegetation was assessed.

Results

Seed banks were dominated by annuals and graminoids. Smoke treatment had no effect, except for driving significantly higher species richness and seedling density in south‐facing slope perennial shrubs. Species richness and seedling density were significantly higher in seed banks on the south‐facing slope compared to the north‐facing slope. Burned standing vegetation exhibited significantly higher diversity than unburned vegetation. Annuals and graminoids displayed significantly higher species richness and aerial cover in burned renosterveld. The north‐facing slope contained less than half the number of species/m² compared to the south‐facing slope. The seed banks and standing vegetation showed low to intermediate similarity (Sørensen = 31%–53%), but grouped close together on an NMDS plot, suggesting intermediate similarity overall.

Conclusions

Elevated germination of perennial shrubs in smoke‐treated seed bank samples and increased diversity of post‐fire standing vegetation suggest the renosterveld in this study shows elements of a fire‐driven system. Certain species only recruited in burned sites, suggesting fire‐stimulated germination. Aspect had a major influence on plant community composition, with the mesic south‐facing slope being more diverse than the xeric north‐facing slope. The similarity between the seed banks and standing vegetation was higher than previously shown for renosterveld, and appears to be higher than for fynbos.     

Seed Stores for Restoration of Species-Rich Shrubland Vegetation Following Mining in Western Australia

The extreme species richness of native shrubland vegetation (kwongan) near Eneabba, Western Australia, presents a major problem in the restoration of sites following mineral sand mining. Seed sources available for post-mining restoration and those present in the native kwongan vegetation were quantified and compared. Canopy-borne seeds held in persistent woody fruits were the largest seed source of perennial species in the undisturbed native vegetation and also provided the most seeds for restoration. In undisturbed vegetation, the germinable soil seed store (140–174 seeds · m^?2) was only slightly less than the canopy-borne seed store (234–494 seeds · m^?2), but stockpiled topsoil provided only 9% of the germinable seeds applied to the post-mining habitat. The age of stockpiled soil was also important. In the three-year-old stockpiled topsoil, the seed bank was only 10.5 seeds · m^?2 in the surface 2.5 cm, compared to 56.1 to 127.6 seeds · m^?2 in fresh topsoil from undisturbed vegetation sites. In the stockpiled topsoil, most seeds were of annual species and 15–40% of the seeds were of non-native species. In the topsoil from undisturbed vegetation, over 80% of the seeds were of perennial species, and non-native species comprised only 2.7% of the seed bank. Additional seeds of native species were broadcast on restoration areas, and although this represented only 1% of the seed resources applied, the broadcast seed mix was an important resource for increasing post-mining species richness. Knowledge of the life-history characteristics of plant species may relate to seed germination patterns and assist in more accurate restoration where information on germination percentages of all species is not available.     

Comparative effects of different smoke treatments on germination of Australian native plants

Abstract This study consists of a series of investigations designed to determine the potential of concentrated smoke products to stimulate seed germination and assist in the rehabilitation of degraded landscapes. Aerosol smoke and conventional smoke water products are not practical for use in broad‐scale seed bank regeneration programmes due to infrastructure limitations and the high rate of application required for their use. Concentrated smoke products have been found to be effective in stimulating soil seed banks and are suitable for broad‐scale use due to the lower rate of application required to elicit germination within smoke‐responsive species. The use of concentrated smoke products on undisturbed soil seed banks at 50 and 100 mL m^‐2 increased total seedling numbers 10‐fold, while species richness more than doubled over untreated controls. Although aerosol smoke applied directly to soil promoted 10 times more seedlings compared to concentrated smoke products, species richness levels in each treatment were similar. Concentrated smoke products cause leaf scorch when applied directly over plants in active growth, with limited to nil damage when plants are not actively growing. The affected plants generally recovered following application of concentrated smoke products as a foliar spray.     

Does invasion by an alien plant species affect the soil seed bank?

Questions: How does invasion affect old‐field seed bank species richness, composition and density? How consistent are these effects across sites? Does the soil seed bank match vegetation structure in old‐fields? Location: Menorca, Balearic Islands, Spain, western Mediterranean basin. Methods: We monitored seed germination in soils from old‐fields that were both uninvaded and invaded (legacy effect) by the annual geophyte Oxalis pes‐caprae. We also added O. pes‐caprae bulbs to uninvaded soils to test O. pes‐caprae interference with seedling emergence (competitive effect). We compared species composition in the seed bank with that of the vegetation. Results: Species richness in the seed bank and in the vegetation was not significantly different between invaded and uninvaded areas. Uninvaded areas did not have larger seed banks than invaded areas. More seedlings, especially of geophytes, emerged when O. pes‐caprae bulbs were added to the soil. Species similarity between invaded and uninvaded areas was higher in the seed bank (74%) than in the vegetation (49%). Differences in species composition were as important as differences among sites. The degree of species similarity between the seed bank and the vegetation was very low (17%). Conclusions: Despite invasion by O. pes‐caprae not affecting species richness, the variation in the seed bank species composition in invaded and uninvaded areas, and the differences between the seed bank and the mature vegetation, highlights that even if the invader could be eradicated the vegetation could not be restored back to the exact composition as found in uninvaded areas.     

Rehabilitation of a Bauxite Tailing Substrate in Central Amazonia: The Effect of Litter and Seed Addition on Flood‐Prone Forest Restoration

Impacts of mining activity can be particularly difficult to remediate in wetland ecosystems subject to inundation pulses due to the reduced length of the plant growing season. We used a factorial experiment to test whether litter and seed addition could be used to increase the efficiency of ecological restoration on a flood‐prone forest (known as igapó) impacted by deposition of bauxite tailings. Our results clearly showed that the addition of litter collected from pristine igapó areas increased plant growth, seedling density, and seedling species richness. The increase in individual plant growth was echoed at the community level with higher leaf area index values on litter addition plots compared to controls. Litter addition can enhance reaccumulation of nutrient pools during successional development, which has been proposed as an important feature to ensure self‐sustainability of areas under restoration. The success of the seed addition treatment depended on the species used. Of the seven sown species, only Acosmium nitens (a leguminous nitrogen‐fixing species) showed high establishment. The introduction of nitrogen‐fixing species is also expected to build up the nitrogen pool in the system as has been reported for restoration programs in non‐inundated forests. These practices have the advantage, compared to direct fertilizing, of not causing eutrophication of water bodies when applied to flood‐prone vegetation.     

Waterproofing Topsoil Stockpiles Minimizes Viability Decline in the Soil Seed Bank in an Arid Environment

Topsoil is a valuable resource for revegetation of mine sites as it contains seeds of plant species indigenous to the local environment. As mine site restoration is undertaken after the completion of mining, it is a common practice to stockpile topsoil in preparation for restoration activities. While many studies have found a decrease in seedling emergence with increasing stockpile age in temperate regions around the world, a few examine the effect of stockpile age on topsoil seed bank and seedling recruitment in arid environments. Seed longevity is promoted under dry conditions whereas viability loss is increased under warm and moist conditions. Here in a study in Australia's Great Sandy Desert, the effect of topsoil storage age and method of storing topsoil (under‐cover and exposed) on seedling recruitment was examined for a major gold mining site. There was a trend for lower seedling emergence (68% lower) and species richness (30% lower) from topsoil stored for 2 years than from topsoil direct returned and topsoil stored for 1 year. Seedling emergence from topsoil stockpiled for 2 years was more than 3.5‐fold higher from covered topsoil stockpiles than uncovered topsoil stockpiles. For two ecologically dominant species, after 2 years of storage, seedling emergence of the grass Triodia basedowii was 13% of direct returned topsoil and seedling emergence of the shrub Acacia stellaticeps was 68% of direct returned topsoil. The implication of the decline in seedling emergence from topsoil stockpiling on mine site revegetation in a biodiverse arid region is discussed.     

Factors Affecting Seed Germination and Seedling Establishment of Fen-Meadow Species

Availability of seeds and provision of “safe sites” for seedling recruitment are essential for successful restoration of seminatural grassland communities. Inability to provide species‐specific conditions for seedling recruitment appears to be a major factor limiting establishment of fen‐meadow species on restoration sites. This contention was tested in the field for both germination and establishment conditions for a selection of fen‐meadow species. A Cirsio‐Molinietum fen meadow and an agriculturally semi‐improved species‐poor grass dominated rush pasture were used. Seeds of Carex ovalis, Cirsium dissectum, Molinia caerulea, Succisa pratensis, and Holcus lanatus were sown onto treatments comprising either irrigation or no irrigation, presence or absence of existing vegetation canopy, and presence or absence of soil disturbance. Germination of all except H. lanatus was higher in the fen meadow than in the rush pasture. The fen‐meadow site was less susceptible to drought, provided more light to the seed environment, and showed a stronger day–night variation in relative humidity compared with the rush pasture. All the fen‐meadow species responded strongly to the experimental treatments, whereas H. lanatus showed only a small response. Soil disturbance was the major factor that increased germination. Removal of the vegetation canopy improved germination only in S. pratensis. Conditions affecting survival of seedlings were different from those affecting seed germination. Seedling survival was greater on the fen‐meadow site than on the rush pasture. Canopy presence was the major factor that reduced seedling survival. Few seedlings survived in the presence of the rush pasture canopy. Irrigation and soil disturbance were of minor importance for seedling survival on both sites. Safe sites for seed germination and seedling establishment of fen‐meadow species existed on the fen meadow even without soil disturbance and gap creation. Safe sites for seedling recruitment were not present in the rush pasture. The need for species‐specific definition of safe site characteristics at the two stages of seedling recruitment (i.e., for seed germination and for seedling survival) was demonstrated. The implications of these findings for restoration of seminatural grasslands are discussed.     

Restoration prospects of abandoned species‐rich sandy grassland in Hungary

Abstract. Secondary succession and seed bank formation was studied in a formerly grazed, abandoned, eastern Hungarian sandy steppe‐meadow (Pulsatillo‐Festucetum). The vegetation was sampled at different elevations of a sand dune which became partly invaded by the tree Robinia pseudo‐acacia ca. 10 yr ago. Pre‐abandonment vegetation records were used as historic references. Though composition of the non‐invaded grassland only changed moderately, dominance of tall grasses (Elymus hispidus, Poa angustifolia) increased significantly at the cost of annuals and low stature perennials. In the stand invaded by Robinia most grassland species were lost and replaced by nitrophytes. Vertical position influenced species abundance, but affected the composition only moderately. Fine‐scale zonation of the vegetation also changed with time. Species richness of the above‐ground vegetation and the seed density of soil samples at the lower elevation were slightly greater than at the higher sites. Seed banks of sensitive grassland specialists (e.g. Pulsatilla pratensis subsp. hungarica) disappeared during grass encroachment. Following extinction from above‐ground vegetation, restoration must rely on dispersal from adjacent areas. In contrast, several annuals and perennials, which survived this degradation stage in the above‐ground vegetation, possessed seed banks. Many of these species became extinct from the vegetation during the Robinia invasion but left viable persistent seeds. This fact is promising for restoration of the Potentillo‐Festucetum sandy pasture. Competitive weedy species and sprouting Robinia can, however, limit seedling establishment.     

A Comparison of Vegetation and Ground‐Dwelling Ants in Abandoned and Restored Gullies and Landslide Surfaces in the Western Colombian Andes

Landslides and gullies are two common manifestations of land degradation in the densely populated Colombian Andes. In these unstable areas, further mass movements pose a serious threat to local populations and cause off‐site environmental damage through sedimentation, pollution, and increased flooding. A novel approach for restoring severely eroded slopes combines the use of stabilization structures made with stalks of Guadua angustifolia Kunth, Poaceae (bamboo), with high‐density planting of species that exhibit quick growth and sprouting. This study compared the vegetation and ground‐dwelling ant assemblages of 10 pairs of gullies, each pair formed by one enhanced and one untreated or control gully, 6–8 years after restoration or abandonment. The restoration treatment had significant effects on the complexity of vegetation. Average values for plant species richness, basal area, stem density, foliage density index, and total vegetation volume were 11.6, 140, 30, 11.5, and 15.6 times larger, respectively, in enhanced than in control gullies. Mirroring the differences in vegetation, average ant species richness was significantly larger (13 vs. 7.6 species per gully), and a higher proportion of ant species nested within enhanced than control gullies (52.5 vs. 30%). While control gullies were dominated by generalist ants such as Ectatomma ruidum and Linepithema angulatum, enhanced gullies had more specialized ground‐dwelling species, normally associated with high plant cover and abundant leaf litter such as Octostruma balzani and Heteroponera inca. We conclude that this restoration strategy promotes a fast recovery of vegetation and the ground‐dwelling ant fauna in these tropical mountains.     

Soil seed banks of fringing salt lake vegetation in arid Western Australia – density,composition and implications for postmine restoration using topsoil

Although studies of seed banks in arid ecosystems are commonplace, they are lacking for the large arid zone of Western Australia. Across the six major plant communities fringing a large salt lake within this zone, topsoil (0–5 cm depth) was collected from 12 to 36 sites per community. Samples were dried, spread out on a bed of vermiculite in seedling trays and placed in a well‐watered glasshouse to determine the readily germinable component of the soil seed bank. Subsamples of topsoil were treated with smoke water, hot water or flooding to help determine seed bank of species with dormancy mechanisms. As with other studies of arid seed banks, large numbers of grasses and forbs emerged from the topsoil, with relatively small numbers of woody perennial species and hummock grasses (Triodia spp.) present, even in communities where such species were dominant. There were, however, a few exceptions where a reasonable density of dominant trees/shrub seed was present in topsoil. Soil treatment generally had limited effect on composition and density of emergent seedlings. Although floristic similarity between soil seed banks and corresponding above‐ground vegetation was modest, there were clear differences in soil seed bank composition between communities. The implications of the results for using topsoils to restore landforms of the study area after mining or other disturbance are discussed.     

Disturbance of suburban Fagus forests by recreational activities: Effects on soil characteristics,above‐ground vegetation and seed bank

Questions: How does recreational disturbance (human trampling) affect soil characteristics, the performance of the understorey vegetation, and the density and species composition of the soil seed bank in Fagus sylvatica forests? Location: Suburban forests near Basel, northwestern Switzerland. Methods: We compared various soil characteristics and the performance of the understorey vegetation in six beech forest areas frequently disturbed by recreational activities with those in six undisturbed control areas, in spring 2003. In the same forest areas, the soil seed bank was investigated using the seedling emergence method. Samples were obtained from soil cores in January 2003. Results: We found substantial changes in soil compaction, above‐ground vegetation and in the soil seed bank due to recreational activities. In frequently visited areas, soil compaction was enhanced which caused a decrease in cover, height and species richness of both herb and shrub layers. Compared with control areas, the number of trampling‐tolerant species of the seed bank was significantly higher in disturbed areas, and total species richness tended to be higher in disturbed than in control areas. Furthermore, the similarity in species composition between the above‐ground vegetation and seed bank was significant lower in disturbed than in control areas. Conclusions: The intensive use of suburban forests for recreational activities, mainly picnicking, affects the vegetation of natural beech forests. Our study indicates that a restoration of degraded forest areas from the soil seed bank would result in a substantial change of the vegetation composition.     

Integrating management techniques to restore subtropical forests invaded by Hedychium coronarium J. Köenig (Zingiberaceae) in a biodiversity hotspot

The restoration of areas invaded by non‐native plants is challenging as invasive plants may affect both biotic and abiotic components of ecosystems, leading to impacts that constrain recolonization by native species after invaders are eliminated. In such a scenario, restoration techniques as topsoil transposition might accelerate colonization by native species in forests. Hedychium coronarium J. Koenig (Zingiberaceae) is a Himalayan herbaceous rhizomatous plant recognized as invasive in several countries. This study aimed to experimentally evaluate the response of plant assemblages to topsoil transposition on a site invaded by H. coronarium after chemical control. Four treatments were applied: chemical control integrated with topsoil transposition, chemical control of H. coronarium alone, topsoil transposition alone, and no intervention (control). Plots were evaluated prior to the application of treatments and then monthly for 11 months after treatments. Parameters were measured for H. coronarium (number of ramets, ramet height, and cover) and other species (species richness, abundance, and cover). Plots treated with chemical control (regardless of topsoil transposition) were similar in terms of all parameters measured and species composition, with dominance of herbs and shrubs. Plots managed solely with topsoil transposition had lower species richness, abundance, and cover, but more diverse life‐forms, being equally rich in climbers, trees, and herbs. Chemical control was effective to control invasion by H. coronarium and increase species richness and abundance on the managed site. Topsoil transposition promoted colonization by species that might accelerate restoration.     

The role of soil seed banks in the restoration of dry acidic dune grassland after burning of Ulex europaeus scrub

Question: Can the seed bank play a significant role in the restoration of plant communities of dry acidic dune grassland where fire has destroyed Ulex europaeus scrub? Location: Northern French Atlantic coast. Methods: One year after the fire, the seed bank and vegetation were sampled in 1 m × 1 m plots along three transects from the oldest scrub vegetation towards the grassland. Differences in species richness, seed density and contribution of ecological groups in the seed bank and vegetation along the transects were analysed. Results: Seed density and species richness in the seed bank decreased significantly from the grassland towards the centre of the scrub vegetation; 50% of the seed bank consisted of core species of the target plant community, such as Carex arenaria, Aira praecox, Rumex acetosella and Agrostis capillaris. Seeds of these species were also found in the deeper soil layers beneath the oldest scrub vegetation, indicating that they can be considered to be long‐term persistent. Beneath the youngest scrub vegetation, seeds of rare satellite target species also occurred. However, no target species were established on the burned site after one year, resulting in a large discrepancy between seed bank and vegetation. Conclusions: Although the seeds present in the soil indicate that restoration of the acidic grassland based on the seed bank is possible, additional management actions such as mowing and soil disturbance may be necessary to restrict resprouting of Ulex and to stimulate the germination of seeds of target species in the deeper soil layers.     

Influence of multiple fire‐related germination cues on three Sydney Grevillea (Proteaceae) species

Abstract Many species found in fire‐prone habitats that possess a soil‐stored seedbank only recruit seedlings in large numbers following a fire. Fire‐related germination cues are presumably used by these seeds as signals that a fire has occurred, and would include the heating that occurs in the soil and the combustion products of burning vegetation, smoke and charcoal. Three Sydney species, Grevillea buxifolia (Sm.) R. Br., Grevillea sericea (Sm.) R. Br. and Grevillea speciosa (Knight) McGillivray, were studied for the interactive effects of these cues on their germination. The germination of all species was found to increase with both smoke and heat treatments. While smoke always had a greater influence than heat, the relationship between the two treatments varied with species. The presence of two fire‐related germination cues should allow these species to take better advantage of the recruitment opportunities of the post‐fire environment.     

Effects of smoke,heat and charred wood on the germination of dormant soil‐stored seeds from a Eucalyptus baxteri heathy‐woodland in Victoria,SE Australia

The effects of dry heat, wet heat, charred wood and smoke on the germination of dormant soil‐stored seeds from a Eucalyptus woodland in western Victoria were tested by using a glasshouse seed‐bank germination experiment. Seedling density, species richness and species composition were compared between replicated treated and control samples. A total of 5922 seedlings, comprising 59 plant species, was recorded from the soil samples over a period of 150 days. While a few species dominated (including Centrolepis strigosa, Wahlenbergia gracilenta and Ixodia achillaeoides), 26 species were represented by fewer than five seedlings and 18 species were restricted to single treatment types. With the exception of charred wood, all treatments led to a significant increase in seed germination relative to the control. The highest number of germinants was obtained for the smoke treatment, with a mean (± SE) of 12 547 ± 449 seedlings m^–2. Heat treatments yielded intermediate densities, with means (± SE) varying between 7445 ± 234 and 9133 ± 445 seedlings m^–2. In comparison with the estimates of seed‐bank sizes from other fire‐prone ecosystems, these densities are high. Species richness differed significantly among treatments. Highest mean richness was recorded in the smoke treatment and lowest for the control and charred wood treatments. There were significant differences in seed‐bank species composition between treatment types based on analysis of similarity (Anosim) using Bray–Curtis similarity. While heat was a specific requirement for triggering germination in hard‐seeded species (e.g. Fabaceae), smoke was the most effective trigger for species from a broad range of other families. The potentially confounding effect of physical and chemical mechanisms of germination stimulation in heated bulk soil samples is raised as an issue requiring further investigation in relation to the role of smoke as a germination trigger.     

Ecological succession in areas degraded by bauxite mining indicates successful use of topsoil

Brazilian ironstone outcrops (cangas) are nutrient‐poor stressful habitat dominated by slow‐growing woody species with high biodiversity and unique evolutionary history. Mining has produced great impacts on this ecosystem. Spontaneous regeneration of abandoned canga mined areas has not been observed. One of the active methods most widely used for ecological restoration in environments where soil has been lost or severely degraded is topsoil transposition due to the physical, chemical, and microbiological improvement of the substrate, in addition to the seed bank. Thus, plant succession was monitored for 40 months after topsoil transposition in a canga area degraded by aluminum mining, without any other type of management. A completely randomized design with 70 permanent plots (1 × 1 m) was used. Annual phytosociological surveys were carried out and floristic and vegetational spectra were constructed with the life‐forms proposed by Raunkiaer. Floristic composition was compared with a reference site. Overall, 105 species were identified. Both flora and vegetation changed over time, increasing resemblance to the reference areas. The floristic and vegetational spectra after 4 years of topsoil deposition are similar to pristine ones. The vegetation spectrum showed an increase in the dominance of phanerophytes and hemicryptophytes, while therophytes reduced their proportion. The early successional stage is dominated by weeds, like in other canga restoration studies, but did not impede the native species regeneration. Cangas's species recruited well from transposed topsoil. Unlike other studies with fertilized topsoil, our findings show the efficiency of topsoil transposition to provide initial conditions for the ecological restoration of this ecosystem.     

Establishment of helophytes in the course of fen restoration

Abstract. In two fen areas of northeastern Germany, different techniques of re-introduction to establish reed-bed species in formerly intensively used, species-poor, grasslands, after rewetting, were studied under three hydrological regimes (permanent inundation, temporary inundation, border irrigation) with the aims (1) to establish peat-forming vegetation and (2) to enhance species richness. Establishment was successful for nearly all species investigated under all hydrological variants. There were differences between individuals sown and those which had been planted. Wet, but not inundated soil linked with vegetation gaps create ‘safe sites’ which enable successful germination and seedling establishment. The survival rate for both planted and sown individuals was generally high, with the exception of Cladium mariscus, Eupatorium cannabinum and Phragmites australis Recommendations for restoration management include the establishment of the following successful species: Carex acutiformis, C elata and C paniculata to establish peat-forming vegetation; Iris pseudacorus, Lysimachia vulgaris, Lythrum salicaria to enhance species richness.