Production and population dynamics of Tubifex tubifex in the profundal zone of a freshwater reservoir in N. Italy

During a study of a pumped storage system from May 1979–June 1980 the profundal macrobenthos of the upper reservoir (Lago di S. Maria Valvestino) was sampled at a fixed station and the population of the tubificid Tubifex tubifex studied in detail. Eggs, embryos and the individuals living in an extra-cocoon stage were counted and individually weighed from monthly samples, according to the methods described in Bonomi & Di Cola (1980). Numerical recruitment during the study period was estimated as 257 000 ind m^–2 yr^–1; of which 110 000 died either as eggs or as embryos, i.e. inside the cocoons, and a further 128 000 died before they attained sexual maturation. The data seem to confirm the typical demographic strategy of T. tubifex i.e. high fecundity and high mortality in the early life stages. The total annual production of the species was estimated at 91.7 g (w.w.) m^–2. The low P/B ratio (2.0 yr^–1) is considered to be mainly due to high population densities.     

Degradation of pentachlorophenol by <Emphasis Type="Italic">Kocuria</Emphasis> sp. CL2 isolated from secondary sludge of pulp and paper mill

A pentachlorophenol (PCP) degrading bacterium was isolated and characterized from sludge of pulp and paper mill. This isolate used PCP as its sole source of carbon and energy and was capable of degrading this compound, as indicated by stoichiometric release of chloride and biomass formation. Based on morphology, biochemical tests, and 16S rRNA gene sequence analysis this strain was identified as Kocuria sp. CL2. High Performance Liquid Chromatography (HPLC) analysis revealed that this strain was able to degrade PCP up to a concentration of 600 mg/l. This is first time we are reporting the degradation of PCP by the Kocuria species. This isolate was also able to remove 58.64% of PCP from the sludge within two weeks. This study showed that the removal efficiency of PCP by CL2 was found to be very effective and can be used in degradation of PCP containing pulp paper mill waste in the environment.     

Nitrification, denitrification, and dechlorination in bleached kraft pulp mill wastewater

This study deals with combining the biologi cal removal of organic halogens with the removal of nitrogen from bleached kraft pulp mill wastewater in fluidized-bed reactors under nitrifying and denitrifying conditions. Untreated and biotreated bleached kraft pulp mill wastewaters had no detrimental effect on nitrification or denitrification. The nitrifying biofilm reactor, pregrown on synthetic inorganic feed with ammonia, removed without a lag phase adsorbable organic halogens [7.2 mg Cl (g biomass volatile solids)⁻¹day⁻¹] from bleached kraft pulp mill wastewater and selected chlorophenols from synthetic wastewater. Electron microscopical examination of the biofilm showed that bacteria, morphologically similar to the nitrifying species Nitrosomonas or Nitrobacter, and Nitrosospira were dominant. The denitrifying fluidized-bed reactor, pregrown on nitrate and methanol, denitrified without a lag phase bleached kraft pulp mill wastewater. Under denitrifying conditions, 35% of the total organic carbon content of untreated bleached kraft pulp mill waste water was removed. The reducing power delivered by untreated bleached kraft pulp mill wastewater for denitrification was 2 mmol electrons/mmol carbon mineralized. Dechlorination under denitrifying conditions was negligible. Received: 21 November 1996 / Received revision: 27 January 1997 / Accepted: 1 February 1997     

The impact of effluents of Pitkäranta pulp mill on the water quality of Lake Ladoga: a model study

The aim of this study is to show the effects of the Pitkäranta pulp mill on the water quality of Northern Ladoga by using water quality models. The effluent loading of the pulp mill with its full production capacity is as follows: Water flow 85 000 m³ d^–1 BOD₅ 2.4 t d^–1 Suspended solids 4.1 t d^–1 tot-N 330 kg d^–1 tot-P 68 kg d^–1 COD(Cr) 14.4 t d^–1 Org. C 6 t d^–1 Lignosulphonates 9.4 t d^–1 Loadings of lignosulphonates and organic C are estimations. Lignosulphonate concentrations of 10.5 mg 1^–1 have been reported in the region of Pitkäranta. The study area of northern Ladoga near the pulp mill was divided into three zones (I, II and III). The mean depth of each of them is considered as 10 m, their respective areas 5, 10 and 50 km², and volumes 50, 100 and 500 million m³. The estimated discharges of the zones are 10, 20 and 50 m³ s^–1, respectively. With the aid of simple water quality models the effects of the pulp mill effluents on the concentrations of oxygen, total phosphorus, lignin, COD(Mn) and Secchi disk depths in each of the zones were estimated. Estimations were made during full production capacity and half production capacity of the pulp mill. The modelling results were compared with the preliminary water analysis results of the Finnish-Russian joint research expedition into Lake Ladoga in August 1993. The results show that near the pulp mill (zone I) phosphorus concentrations are high even with half production capacity. Also lignin and COD(Mn) contents have increased, and oxygen concentrations are low both in the summer and during wintertime. Farther away in the open water (zone III) the pollution effects are low. Eutrophication, indicated by high total phosphorus concentrations, is the main effect of the pulp mill effluents.     

Host–parasite interactions and competition between tubificid species in a benthic community

1. Parasites can be important determinants of host community structure while host community structure can influence the success of parasites, although both are often overlooked. In two laboratory experiments, we examined interactions among Myxobolus cerebralis syn Myxosoma cerebralis Höfer, the myxozoan parasite that causes salmonid whirling disease, and two coexisting tubificid species: Tubifex tubifex (Müller), which is the alternate host of the parasite, and Limnodrilus hoffmeisteri Claparède, which is not susceptible. In the first experiment, we examined T. tubifex infection prevalence when exposed to nine doses of spores. In the second experiment, we examined tubificid and parasite success under three spore doses when tubificids were combined in a response surface experimental design used to detect interactions among species. 2. The outcomes of interactions between tubificid species were complex. The number and biomass of offspring of both tubificid species were density dependent when in monoculture or in combination with the other species. Adult growth of T. tubifex was also density dependent in monoculture, but when L. hoffmeisteri replaced one‐half of the T. tubifex in the high‐density treatment, adult growth of T. tubifex was higher than in monoculture. Adult growth of L. hoffmeisteri was always density independent. Whether T. tubifex was exposed to the parasite or not did not change the outcome of these interactions. However, adult growth of T. tubifex, but not L. hoffmeisteri, was highest when M. cerebralis was present. 3. Infection prevalence of T. tubifex increased with increasing spore dose. Infection prevalence was lowest in the high‐density T. tubifex monoculture and highest in the low‐density T. tubifex monoculture and when T. tubifex was in combination with L. hoffmeisteri. 4. Both intraspecific and interspecific competition influenced tubificid success, but T. tubifex gained some competitive advantage through increased adult growth when in combination with L. hoffmeisteri. Whether T. tubifex was exposed to the parasite or not did not change the outcome of the interactions between the tubificid species. 5. The presence of L. hoffmeisteri did not decrease the prevalence of infection in T. tubifex, suggesting that parasite success was unaltered by the presence of this non‐susceptible species.     

Habitat use and movement patterns of bull sharks Carcharhinus leucas determined using pop‐up satellite archival tags

Habitat use, movement and residency of bull sharks Carcharhinus leucas were determined using satellite pop‐up archival transmitting (PAT) tags throughout coastal areas in the U.S., Gulf of Mexico and waters off the south‐east U.S. From 2005 to 2007, 18 fish (mean size = 164 cm fork length, L_F) were tagged over all seasons. Fish retained tags for up to 85 days (median = 30 days). Based on geolocation data from initial tagging location to pop‐off location, C. leucas generally travelled c. 5–6 km day^?1 and travelled an average of 143·6 km. Overall, mean proportions of time at depth revealed C. leucas spent the majority of their time in waters <20 m. They exhibited significant differences among depths but were not found at a particular depth regardless of diurnal period. Most fish occupied temperatures c. 32° C with individuals found mostly between 26 and 33° C. Geolocation data for C. leucas were generally poor and varied considerably but tracks for two individuals revealed long distance movements. One fish travelled from the south‐east coast of the U.S. to coastal Texas near Galveston while another moved up the east coast of the U.S. to South Carolina. Data on C. leucas movements indicated that they are found primarily in shallower waters and tend to remain in the same location over long periods. While some individuals made large‐scale movements over open ocean areas, the results emphasize the importance of the coastal zone for this species as potential essential habitat, particularly in areas of high freshwater inflow.     

互花米草入侵对大型底栖动物群落垂直结构的影响

2012年8月,在浙江省玉环县漩门湾国家湿地公园,利用自制分层采样器,以5 cm为单位对0—25 cm泥层进行分层取样,研究潮间带互花米草滩涂和自然滩涂两种生境中大型底栖动物的垂直分布情况,以及互花米草入侵对大型底栖动物垂直结构的影响。两种生境中共获得大型底栖动物40种,其中软体动物18种,甲壳动物13种,环节动物4种,其他类群5种。在自然滩涂生境中获得的物种数为30种,互花米草生境为31种,两种生境的共有种有21种。互花米草和自然滩涂生境平均栖息密度分别为222.6株/m2和1052.8株/m2。研究结果表明:(1)大型底栖动物主要栖息在0—10 cm泥层深度;(2)大型底栖动物群落沿泥层深度存在分层分布现象;(3)互花米草入侵缩短了底栖动物的垂直分布距离,但对其主要栖息深度影响不大;(4)互花米草入侵改变了原来生境特征,导致大型底栖动物的群落结构发生变化。     

Countering morphological ambiguities: development of a PCR assay to assist the identification of <Emphasis Type="Italic">Tubifex tubifex</Emphasis> oligochaetes

The freshwater oligochaete, Tubifex tubifex, is a common resident of organic-rich sediments worldwide. Although it is a familiar species to fish enthusiasts, toxicologists and parasitologists, T. tubifex often confounds definitive identification due to the similarity that immature specimens bear to several other common oligochaetes, and given the degree of plasticity of key morphological characters due to environmental conditions and/or age of specimen. To solve this identity crisis, we used a polymerase chain reaction based molecular approach and developed a T. tubifex specific assay with primers that amplify a 192 bp fragment of the internal transcribed spacer region 1 ribosomal DNA. We tested these primers on four T. tubifex mitochondrial genotypes, and on other oligochaete species from nine genera. The primers amplified all specimens identified morphologically asT. tubifex. They did not amplify any other species, including morphologically similar worms possessing hair chaetae (Dero digitata, Ilyodrilus templetoni, Tubifex ignotus or Rhyacodrilus spp.) or other oligochaetes often found with T. tubifex (Lumbriculus variegates, Limnodrilus hoffmeisteri, Stylodrilus heringianus or Trichodrilus sp.). This technique should remove the uncertainties all too often associated with identification of T. tubifex.     

Colonization of growing radish plants by clinical and nonclinical isolates ofKlebsiella inoculated onto seeds

Klebsiella was found to multiply and colonize growing radish root bulb surfaces following the inoculation of seeds with 10¹–10⁴ cells. All 29 cultures ofKlebsiella originally isolated from 5 different sources were capable of growth to 10⁶–10⁷ colony-forming units/g of root bulb within 1 week after seed germination. Linear regression analysis illustrated differences inKlebsiella survival rates over 4 weeks of radish plant development. Analysis of covariance showed the survival ability wasKlebsiella from vegetables>mastitis>human, water, and pulp mill isolates. It was also shown thatKlebsiella species 2 had a significantly higher survival rate than the otherKlebsiella species. This finding correlates well with the observation thatKlebsiella species 2 is the most commonKlebsiella species isolated from vegetables. Average densities for allKlebsiella groups at plant harvest (5 weeks) ranged from 10³–10⁵ colony-forming units/g of radish plant. The possible health significance of these densities ofKlebsiella on vegetables consumed raw by humans is discussed.     

Habitat characteristics of juvenile cowcod, <Emphasis Type="Italic">Sebastes levis</Emphasis> (Scorpaenidae), in Southern California

We characterized habitat requirements of juvenile cowcod, Sebastes levis, using information from surveys conducted aboard the manned research submersible Delta. We conducted 303 dive surveys on rocky banks and outcrops in water depths between 28 and 365 m in southern and central California, covering 483 km (963,940 m²) of seafloor. We counted 549,263 fishes from at least 134 species; 216 individuals were juvenile cowcod, S. levis, of 45 cm or less in total length (TL). Juvenile cowcod occupied depths between 52 and 330 m and demonstrated ontogenetic shifts in their habitat associations. Small fish (5–20 cm TL) lived primarily among cobbles or cobbles and small boulders. As fish grew, they moved into high-relief rock habitats, including boulder fields and rock ridges. Small cowcods were found with pygmy, Sebastes wilsoni, and swordspine, Sebastes ensifer, rockfishes. Larger juveniles often associated with juvenile bocaccio, Sebastes paucispinis, juvenile widow rockfish, Sebastes entomelas, and squarespot rockfish, Sebastes hopkinsi. Our study resulted in a characterization of seafloor habitats on a small spatial scale that is relevant to juvenile cowcod nursery areas, which is important when considering effective management strategies for this overfished species.     

Changes in growth of two C4 grasses (Schizachyrium scoparium and Paspalum plicatulum) in monoculture and mixture: influence of soil depth

The growth of Schizachyrium scoparium (Michx.) Nash (little bluestem) and Paspalum plicatulum Michx. (brownseed paspalum), two C₄ grasses, was examined in monoculture and in mixed culture in three soil depths. Effects of soil depth and competition were both significant. Growth of both species increased as soil depth increased from 30 to 180 cm in pot experiments. However, P. plicatulum dry mass increased approximately four times more than S. scoparium as soil depth increased. Schizachyrium scoparium dry mass was always greater in monoculture while P. plicatulum dry mass was always greater in mixture. Significant interspecific competition was not measured in the shallow soil treatment (30 cm) suggesting equal competition. Significant interspecific competition was measured in the deeper soil treatments (90 and 180 cm), and P. plicatulum dry mass was clearly greater in mixtures in the two deeper soils. Paspalum plicatulum does not appear to prevent the growth of S. scoparium roots in the deeper soil, but seems able to exploit deeper soil resources by proliferating roots at depths where S. scoparium roots do not seem capable of growth.     

Meiofauna of the profundal zone of the northern part of Lake Ladoga as an indicator of pollution

Benthic meiofauna was sampled at 19 stations, mainly in the northern part of Lake Ladoga, from depths between 13 and 199 m and from types of environment ranging from sheltered areas near pollution sources to less polluted open areas. About 80 taxa were identified, of these 70 to the species level. The greatest numbers of species were oligochaetes (24 species) and harpacticoids (8 species). Certain quantitative ratios of meiofauna were shown to be correlated with environmental data. The species of the oligochaete families Lumbriculidae and Aeolosomatidae and the harpacticoids as a collective group, excluding Canthocamptus staphylinus, were most clearly confined to the less eutrophied environments. The oligochaete species Amphichaeta leydigii, Dero digitata and Tubifex tubifex, the resting stages of Cyclopinae, and Eucyclops serrulatus among the Eucyclopinae were most clearly concentrated in the eutrophicated or polluted environments. The groups of Naididae, Cladocera and Eucyclopinae did not have much value as indicators. Shannon diversity index correlated positively with the total phosphorus content of the water, and number of species decreased with increasing depth. In general, it seems that the pollution tolerance of the meiofauna in a very large lake such as Lake Ladoga is high, presumably due to the effective mixing of water masses.     

A comparison of two tubificid oligochaete species as candidates for sublethal bioassay tests relevant to subtropical and tropical regions

Two tubificid oligochaetes, Branchiura sowerbyi and Tubifex tubifex, were evaluated as potential test organisms for sediment bioassays. We attempt to reproduce the sediment bioassay proposed by Reynoldson et al. (1991) using his strain of Tubifex tubifex and his reference sediment and to compare this technique using Branchiura sowerbyi. This species was chosen because it is more common and dominant in tropical and subtropical environments than Tubifex tubifex. Data on survival and reproduction were obtained for both species, and growth estimates were obtained for B. sowerbyi. The sublethal bioassay with T. tubifex confirmed earlier estimates of a test duration of 4 weeks at 22.5 °C. B. sowerbyi cultures can produce usable estimates in 21 days at 30 °C.     

Growth of Tubifex tubifex Müller (Oligochaeta,Tubificidae) under Various Trophic Conditions

Growth of Tubifex tubifex on highly caloric activated sludge and poor in organic matter natural silt was experimentally studied. The relationship between oxygen consumption rate, weight, and caloric value of T. tubifex body in culture on activated sludge was determined to calculate the growth efficiency (K₂ = P/P + R). The growth rate has been determined, and models of T. tubifex growth are given under various trophic conditions conforming to results of the experiment. Somatic growth, generative growth and life span of this species were compared on the basis of the experiments and literature. Acceleration of growth and prolongation of life under conditions of caloric food and delay of these processes in silt poor in organic matter have been established and measured. T. tubifex was found to have advantages as compared to other tubificid species in response to increasing amounts of nutrient food in waters polluted by organic matter and, therefore, to produce abundant populations under these conditions.     

Population analysis in mass cultures of Tubifex tubifex

Mass cultures of Tubifex tubifex from Lake Orta were kept in the lab at 20 °C starting with different initial densities (10, 45, 86, 161 ind · jar^–1), with the aim of evaluating the effect of density on population numbers and on population parameters. The results show that density mainly controls fecundity, growth, maturation and ovigeration rates. Growth rates and mean number of eggs laid/ovigerous (R₀) are inversely related to density, but generation time appears to be directly related. Very low or very high initial densities display, at different times of the culture history, efficient density controls. Intermediate N₀ seem to bring about situations of bad control, easily leading to numerical overshoots. A possible implementation of a population dynamics model (Bonomi & Di Cola, 1980), originally used for laboratory observations on T. tubifex cohorts was considered, including some density control functions derived from our observations on cohort and mass cultures in some transfer rates and in fecundity rate.     

Indicative profundal oligochaete assemblages in selected small Swedish lakes

Fifty-seven small- to middle-size lakes of Sweden (size-range from <0.1 to about 200 km²) representing different regions and lake-types were selected for the purpose of demonstrating the indicative value of profundal oligochaete communities also of relatively small lakes. It is well known since previously that profundal oligochaete assemblages of large lakes in Europe may be particularly indicative of the current trophic situation, but little has been known about smaller lakes in this respect. Characterizations based on oligochaete community structure in these lakes could be summarized in eight different groups: Characteristic oligochaete communities in oligotrophic lakes of relatively small size are Spirosperma ferox, Stylodrilus heringianus and Tubifex tubifex. Oligochaete species richness is low (1–3 species) and so is species abundance (<300 specimens m^–2). Very eutrophic lakes of the same size-range are largely dominated by the tubificids Limnodrilus hoffmeisteri and/or Potamothrix hammoniensis. Substitute or complementary species may be T. tubifex. Species richness is usually low (1–3 species), but abundance is high to very high (>5000 specimens m^–2). Mesotrophic to moderately eutrophic lakes of the same size categories contain more species than the above extremes, most of them being fairly tolerant to oxygene deficiency such as Tubifex ignotus, a number of species of the genera Aulodrilus and Limnodrilus and a variety of so-called Ponto-Caspian Potamothrix species, most of them having recently invaded south-eastern Sweden. Species richness is moderate to high (4–8 species), while abundance may vary considerably (range from about 300 to about 5000 specimens m^–2). In this respect, small- to middle-size lakes do not differ much from larger lakes. For the trophic characterization of lake water the mean concentrations of total-phosphorus (in g l^–1) is generally regarded to be the most appropriate measure. The match between characterizations based upon oligochaete community structure and total-phosphorus concentrations is generally very good for large lakes. The present study shows that this applies fairly well also to the majority of the small- to middle-size lakes selected for this study. This has not been shown before. Obvious deviations from this rule could be caused by a scarcity of reliable chemical data, or considerable seasonal shifts in the chemical composition ot the water, which in its turn may be caused by short water residence time. Littoral elements in the fauna, which are generally less indicative, or effects of local inflows may also be more frequent here than in lakes of larger size.     

Coarse root spatial distribution determined using a ground-penetrating radar technique in a subtropical evergreen broad-leaved forest, China

Coarse roots play a critical role in forest ecosystems and both abiotic and biotic factors affect their spatial distribution. To some extent, coarse root density may reflect the quantity of root biomass and biotic competition in forests. However, using traditional methods (e.g., excavation) to study coarse roots is challenging, because those methods are time-consuming and laborious. Furthermore, these destructive methods cannot be repeated in the same forests. Therefore, the discovery of non-destructive methods for root studies will be very significant. In this study, we used a ground-penetrating radar technique to detect the coarse root density of three habitats (ridge, slope and valley) and the dominant tree species (Castanopsis eyrei and Schima superba) in a subtropical forest. We found that (i) the mean of coarse root density for these three habitats was 88.04 roots m^?2, with roots being mainly distributed at depths of 0–40 cm. Coarse root densities were lower in deeper soils and in areas far from the trunk. (ii) Coarse root densities differed significantly among the three habitats studied here with slope habitat having the lowest coarse root density. Compared with S. superba, C. eyrei had more roots distributed in deeper soils. Furthermore, coarse roots with a diameter >3 cm occurred more frequently in the valleys, compared with root densities in ridge and slope habitats, and most coarse roots occurred at soil depths of 20–40 cm. (iii) The coarse root density correlated negatively with tree species richness at soil depths of 40–60 cm. The abundances of the dominant species, such as C. eyrei, Cyclobalanopsis glauca, Pinus massoniana, had significant impacts on coarse root density. (iv) The soil depth of 0–40 cm was the “basic distribution layer” for coarse roots since the majority of coarse roots were found in this soil layer with an average root density of 84.18 roots m^?2, which had no significant linear relationships with topography, tree species richness, rarefied tree species richness and tree density. Significant relationships between coarse root density and these factors were found at the soil depth of 40–60 cm, which was the “potential distribution layer” for coarse root distribution.     

Isolation and characterization of novel Serratia marcescens (AY927692) for pentachlorophenol degradation from pulp and paper mill waste

Seven aerobic bacterial strains were isolated from pulp paper mill waste and screened for pentachlorophenol (PCP) tolerance on PCP containing mineral salt agar medium (MSM). The organism was characterized by 16S rDNA sequencing which showed 99.7% sequence similarity with Serratia marcescens. PCP degradation was routinely monitored with spectrophotometric analysis and further confirmed by HPLC analysis. Among seven strains, ITRC S₇ was found to degrade up to 90.33% of 1.127 mM (300 mg/l) of PCP and simultaneous release of chloride ion (2.435 mM) emphasized the bacterial dechlorination in the medium in presence of glucose as an additional carbon and energy source under optimized condition within 168 h incubation. In absence of glucose bacterium was unable to utilize PCP indicating the phenomenon of co-metabolism. Bacterium was identified as S. marcescens (AY927692), was a novel and potential aerobic bacterial strain capable of degrading PCP in axenic condition. Further, this strain may be used for bioremediation of PCP containing pulp paper mill waste in the environment.     

A morphological reappraisal of Tubifex blanchardi Vejdovský, 1891 (Clitellata: Tubificidae)

Tubifex blanchardi Vejdovský, 1891 is a freshwater tubificid, often living in sympatry with Tubifex tubifex (Müller 1774). Although considered from its discovery as a species on its own, its biological status is debated. During the early seventies T. blanchardi was reduced to a mere form of T. tubifex, as a particular case of polymorphism in chaetal pattern. Using classical histological techniques, microdissections of portions of the male genital apparatus and phalloidin staining of dissected copulatory organs we investigated 163 mixed individuals of T. blanchardi and T. tubifex belonging to sympatric populations from the Lambro River (Milan, Northern Italy). The internal morphology of T. blanchardi is described for the first time. Our results show that T. tubifex and T. blanchardi differ in several characters concerning both their external and internal morphology, and in the fine organization of their copulatory organs. Several independent character sets support the separation of T. blanchardi from T. tubifex, suggesting that it is an independent species. This study also supports the idea that T. blanchardi and T. bergi (Hrabě, 1935), another species closely related to T. tubifex, are not conspecific. The observed morphological differences between allopatric populations of T. tubifex are discussed.     

Implications of Seedling Emergence to Site Restoration following Bauxite Mining in Western Australia

Seedling emergence of 12 selected northern jarrah (Eucalyptus marginata Donn ex Smith) forest species were investigated to assist Alcoa of Australia Ltd. in maximizing the establishment of topsoil species in rehabilitated bauxite mining sites. The species, which encompassed a range of seed weights (0.024 mg to 87 mg), plant families, seed-storage types, life forms, and germination requirements, were placed on the soil surface and at depths of 1, 2, 5, 10, and 15 cm under controlled conditions in a glasshouse. Ability to emerge from deep burial was found to depend on seed size for species that annually release their seed to the topsoil but not for species that store their seed on the plant. All selected species were capable of emerging from 2 cm depth of burial, but eight of the 12 species were either unable to emerge from 5 cm or showed a significant reduction in emergence from 5 cm depth of burial compared to optimally buried seed. This group included two small-seeded species, Stylidium calcaratum and Chamaescilla corymbosa; the major forest dominant, Eucalyptus marginata; the serotinous canopy-borne seed of Hakea amplexicaulis; and the wind-dispersed seed of Xanthorrhoea gracilis. A few seeds of the legume species Kennedia coccinea, Acacia pulchella, and Bossiaea aquifolium established seedlings from depths of 15 cm. Currently, Alcoa removes the upper 15 cm of topsoil separately from the underlying soil prior to the commencement of mining. This topsoil is respread at a similar depth following mining as part of the rehabilitation procedure. It is recommended that Alcoa continue to strip topsoil to a depth of 15 cm but investigate the option of re-spreading topsoil onto rehabilitated pits at a shallower depth to maximize establishment via the soil seed bank.