Recolonization of regenerating open forest by terrestrial lizards following sand mining

The terrestrial lizard fauna of a regenerating mining path situated in open forest on coastal sand dunes was surveyed by pitfall trapping. The regeneration age of the series of chronosequence plots used ranged from 3.9 to 15.9 years. No lizards were recorded on plots less than 5.9 years old. Only four species of lizard were regularly found on the mining path. The skink Ctenotus robustus was the first colonizer and attained peak abundance and biomass after 9 years’ regeneration. Amphibolurus muricatus and Ctenotus taeniolatus were less abundant than C. robustus and did not appear on the mining path until 9 to 11 years’ regeneration. The abundance of C. taeniolatus continued to increase up to the oldest age class (16 years). Linear multiple regression analysis showed that sparse patchy vegetation in the 0–1 m layer and the amount of live shrub cover jointly accounted for 72% of the variance in abundance and 68% of variance in biomass for C. robustus. Fifty percent of the variance in C. taeniolatus abundance was explained by the proportion of plant species endemic to forest, regeneration age and the patchiness in understorey vegetation height. However, 67% of C. taeniolatus biomass was accounted for by plant species richness, plant species diversity, and the proportion of endemic forest and heath plant species. Some lizard species recorded from the surrounding forest were not found on the mining path. Lizards appear to recolonize revegetated areas more slowly than some other animal groups; this ‘sensitivity’ implies that they can act as important ‘indicator species’ of successful regeneration in disturbed areas. The non-linear response with time of some habitat variables makes it difficult to predict the time required for the complete rehabilitation of the mining path; however, it seems likely that a period well in excess of 20 years may be necessary before the lizard fauna on the mining path reaches premined levels.     

Vegetation development in dune slacks: the role of persistent seed banks

Abstract. The soil seed bank composition was determined at four sites in the dune slack ‘Koegelwieck’ on the Dutch Wadden Sea island of Terschelling. At three different sites in the slack, where sod-cutting experiments down to the mineral sand had been carried out, the established vegetation and seed bank were assessed after 5, 9 and 39 yr of undisturbed development, respectively. In addition, a fourth site in the slack was investigated, where vegetation development had proceeded for 80 yr since plant colonization of bare soil and where nowadays a vegetation dominated by Calamagrostis epigejos and Salix repens occurs. Together these four sites can be regarded as a chronosequence of dune slack formation. Clear time sequences were detected in the seed bank data. Many late successional species showed a significant increase in the number of seeds during the succession. Some of the early successional basiphilous pioneer species such as Anagallis minima, Centaurium littorale, Littorella uniflora, Radiola linoides and Samolus valerandi, showed either a decrease during the time of succession or an optimum in the vegetation while remaining present in the seed bank in low but detectable numbers. They could, therefore, play a role in re-establishment of the vegetation after sod-cutting. One of the target species, Schoenus nigricans, established within a few years after removal of the sod. However, no seeds of this species have been detected in the soil below either of the successional stages. Based on the species disappearance from the established vegetation and based on the independent data of Thompson et al. (1997) an estimation of seed longevity could be made for several Red List species of wet dune slacks.     

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.     

Recolonization of coastal heath by Pseudomys novaehollandiae (Muridae) following sand mining

The regeneration of coastal heath after disturbance by mineral sand mining was studied on mid-seral stages from 4 to 11 years old at Hawks Nest, N.S.W. The main purpose was to gain some understanding of factors influencing recolonization by pioneer species of small mammals such as Pseudomys novaehollandiae. Changes in floristics and vegetation structure with time were studied as possible contributing factors together with environmental variables. An apparently linear relationship was found between plant species diversity (X₁) and P. novaehollandiae biomass which was also correlated with an index representing the proportion of heath species present (X₂). Both plant species diversity and P. novaehollandiae biomass showed a linear increase with regeneration age. A multiple regression analysis revealed a predictive equation explaining 96% of the variation in P. novaehollandiae biomass (Y): Y=-7.92 + 1.21X₁+3.92X₂ - 3.09X₃ The third variable (X₃) is a measure of soil hardness. A path diagram using contribution coefficients based on a partial correlation analysis included the effects of vegetation structure below 50 cm and regeneration age. On mid-seral stages after sand mining P. novaehollandiae is associated with areas having a variety of heath plants, with vegetation cover below 50 cm and softer substrates; its abundance increases with increasing regeneration age and with the total amount of vegetation present. A minimum of 20 years is seen to be necessary for both total amount of vegetation and P. novaehollandiae biomass to reach values encountered on control plots of undisturbed heath.     

Secondary successional patterns in a sagebrush (Artemisia tridentata) community as they relate to soil disturbance and soil biological activity

The relationship between secondary succession, soil disturbance, and soil biological activity were studied on a sagebrush community (Artemisia tridentata) in the Piceance Basin of northwestern Colorado, U.S.A. Four levels of disturbance were imposed. I: the vegetation was mechanically removed and as much topsoil as possible was left; 2: the vegetation was mechanically removed and the topsoil scarified to a depth of 30 cm; 3: topsoil and subsoil were removed to a depth of 1 m, mixed and replaced; 4: topsoil and subsoil were removed to a depth of 2 m and replaced in a reverse order. Plant species composition, dehydrogenase and phosphatase enzymatic activity, mycorrhizae infection potentials, and percent organic matter were the variables measured.Treatment 4 drastically altered the pattern of vegetation succession. Treatments 2, 3, and 4 started with Salsola iberica as the dominant species but six years later, 3 and to lesser extent 2 changed in the direction of the species composition of 1, dominated by perennial grasses and perennial forbs. Treatment 4 developed a shrub dominated community. The rate of succession was not decreased by the increased levels of disturbance. Both dehydrogenase enzyme activity and mycorrhizae infection potential (MIP) increased with the change from Salsola iberica to a vegetation dominated by either perennial grasses and forbs or shrubs. The intensity of disturbance in 2, 3, and 4 reduced drastically dehydrogenase activity and MIP, but in six years they recovered to levels comparable to 1. Phosphatase enzyme activity and organic matter were unrelated to species composition but related to treatment and time elapsed. In both cases a significant decrease was observed throughout the six-year period.Nomenclature followsThis study was funded by the United States Department of Energy under Contract No. DE-AS02-76EV04018.     

Habitat correlates of the distribution and biomass of Seychelles' reef fishes

Synopsis Relationships between quantitative measures of habitat type and the biomass of Chaetodon, Scarus and Parupeneus species were investigated across 35 reef sites in the Inner Seychelles Group. Multiple regression was used to determine the proportion of variance in biomass between sites which could be explained by depth, exposure, vertical relief, topographic complexity, live coral cover, coral rubble cover, rock cover, sand cover, underlying carbonate substrate, underlying sand substrate, underlying rock substrate and an index of fishing intensity. A significant proportion of the variance in biomass was explained by habitat variables and the index of fishing intensity for 7 of 12 Chaetodon species (23–52% of variance explained), 3 of 6 Parupeneus species (33–40%), and 10 of 13 Scarus species (14–46%). Within genera, different groups of habitat variables explained the variance in biomass for different species and, of the variables studied, only the proportion of underlying sand substrate failed to explain a significant proportion of the variance in biomass for any species. Quantitative relationships between the biomass of Chaetodon and habitat were often in accordance with those suggested by previous studies of their ecology, life-history and distribution at other Indo-Pacific locations. However, the habitat associations of the Parupeneus and some Scarus species have not been studied at other locations and clearly warrant further investigation. It was concluded that habitat was an important determinant of the distribution of many Seychelles reef fishes, but that the habitat variables examined were rarely the most important determinant of biomass. However, the inclusion of a procedure to collect habitat data provided a useful means by which to reduce the unexplained variance associated with visual census biomass estimates and therefore improves the possibility of elucidating the effects of other factors on the biomass of Seychelles reef fishes.     

山西平朔露天矿区不同年限复垦地植被重建特征对比分析

平朔矿区是中国首个露井联采的亿t级矿区,剧烈的采煤活动导致矿区局部植被彻底损毁,植被重建是矿区生态系统恢复重建的保障,目前针对长期复垦序列下矿区复垦地植被重建特征与演替规律的研究较少。以复垦年限分别为6 a、7 a、25 a和27 a的复垦排土场和原地貌样地为研究对象,采用时空替代法和描述性统计分析法分析了不同复垦年限下复垦地的植被重建特征,并与原地貌进行了对比分析。研究结果表明：(1)植被重建工作显著提高了复垦地的物种丰富度,各复垦地乔灌植株的物种丰富度明显高于原地貌。但在重建植被演替过程中,并非随复垦年限增加,物种丰富度越来越高;复垦地Shannon-Wiener指数随复垦年限增加呈先增后减的变化趋势,该值在R-25a样地达到峰值(0.62),其与复垦地的植物物种组成及其自身生长习性、土壤条件、降水等自然条件和人为干扰等息息相关。(2)从乔木植株的生长状况来看,刺槐作为先锋树种,是植被重建时可优先选择的乔木树种。从复垦地草本植株组成来看,草本植物以多年生为主,占比77.78%;从草本植株的重要值来看,草本优势种以禾本科(Gramineae)、菊科(Compositae)和豆科(Le...     

Climate and pH as determinants of vegetation succession in Central European man‐made habitats

Questions: (1) What are the most important abiotic environmental variables influencing succession in central European man‐made habitats? (2) How do these variables interact with one another and with variation in community properties? Location: Central, western and southern parts of the Czech Republic. Habitats included old fields, urban sites, spoil heaps after coal mining, sites at water reservoirs, extracted sand pit and peatland and reclaimed sites in areas deforested by air pollution. Methods: We investigated vegetation patterns on 15 succes‐sional seres, sampled by the same methods. Time of succession over which the data were available ranged from 12 to 76 years. The cover of vascular plant species (in %) was estimated in 5 m × 5 m plots. The relationships between vegetation characteristics (species composition, total cover, cover of woody species, species number and rate of dominant species turnover) and 13 abiotic site factors, including climatic and soil variables, were tested using CCA ordination and regression models. Results: Substratum pH, the only substratum characteristic, and climate were the environmental variables significantly affecting the vegetation patterns in the course of succession. The rate of succession, measured as the turnover of dominant species, was significantly more rapid in lowland than in mountain climates. On alkaline soils, species numbers in succession increased towards warmer climates. However, acid soils prevented any increase in species numbers, regardless of the climate. Surprisingly, forms of nitrogen and contents of C, P and cations did not exhibit any significant effect on the vegetation characteristics studied. Conclusions: Our approach, to compare a number of seres, can contribute not only to our understanding of succession, but also to help restoration projects to predict vegetation change because the crucial environmental variables, as identified by this study, are easy to measure.     

Changes in soil and vegetation during dune slack succession

Many rare plant species occur in Dutch wet dune slacks, particularly in the Junco baltici‐Schoenetum nigricantis. For nature management it is important to understand the processes controlling the presence of these basiphilous early successional communities, which is why we investigated vegetation and soil development during succession in coastal dune slacks. We compared 12 chronosequential stages of 0, 2, 4, 9, 10, 13, 25, 30, 43, 60, 70 and 85 yr in five different dune slack systems. In four of these locations turf had earlier been removed in order to restore the basiphilous pioneer stage. The main variation in the vegetation is related to the acidification/soil enrichment gradient and the salinity/maritime gradient. During succession, organic matter accumulates and acidification takes place. Maritime influence can buffer the soil and postpone the succession of basiphilous pioneer communities for many years. A significant correlation with age was found for 18 variables. Multiple regressions predicted changes in the vegetation (dependent variables: biomass, cover of Salix repens, Calamagrostis epigejos and Schoenus nigricans) as a function of acidification, organic matter accumulation, increase in available P and presence of Na in the soil. We conclude that natural ageing of the vegetation and the associated process of accumulation of biomass drive succession in this hydrosere. The underlying soil processes are acidification and organic matter accumulation. During succession dominance shifts from S. nigricans to S. repens or C. epigejos. Maintenance of the pioneer character of the habitat is only possible by local intervention or by natural or man‐induced dune forming. The effect of sod‐stripping depends on the environmental conditions and, in case of acidification, success is limited. Succession can be postponed by mowing.     

Local variation in rodent communities of Sitka spruce plantations: the interplay of successional stage and site-specific habitat parameters

Habitat associations of wood mouse Apodemus svlvaticus, bank vole Clethrionomvs glareolus and field vole Microtus agrestis were analysed during a chronosequence study of succession in Sitka spruce Picea stichensis plantations in Hamsterley Forest, northeast England In mature plantations (ca 40 yr after planting), A svlvaticus and C glareolus were both abundant, in clear-felled areas the former was usually dominant, in young plantations (5-8 yr after planting) either of the three species was dominant at different sites Pooling all sites, in young plantations rodent communities were most diverse, because of an inter-site component (β-diversity), although within sites, young plantations and mature plantations had similar diversities Clear-felled areas showed least rodent diversity Detrended Correspondence Analysis was used to describe the taxonomic and structural changes in vegetation during succession Canonical Correspondence Analysis showed that in young plantations C glareolus was associated with dense ground cover, provided mostly by heather Microtus agrestis was most commonly associated with Deschampsia flexuosa, whereas A svlvaticus was not strongly associated with any plant species Spatial heterogeneity in soils explained much of the inter-site variation in vegetation winch in turn explained much of the β-diversity of rodent communities in young plantations     

Predictability of early stages of primary succession in post‐mining landscapes of Lower Lusatia,Germany

Abstract. The predictability of early primary succession in post‐mining landscapes of eastern Germany was studied at sites 5–70 yr following dumping. This chronosequence was investigated using indirect ordination methods. The position of the vegetation types in the ordination diagram was found not to infer any temporal sequence. Independent observations show that the change of vegetation type is slow and does not necessarily occur among types adjacent in the ordination diagram. Furthermore, direct ordination revealed that environmental parameters such as pH, the levels of available phosphate and organic carbon as well as the age of the study sites do not significantly account for the variance. Instead, attention needs to be paid to the influence of spatial aspects and also what recultivation measures have been carried out. A detailed account of the vegetation dynamics of individual sample plots showed ‐ depending on the respective vegetation type ‐ divergence, convergence, and fluctuation at the smallest spatial scale. While the species richness of the sample plots remained more or less constant after initial colonization, mean vegetation cover continuously increases with age, although some sites still remain free of vegetation after as long as 70 yr. No general trend in dominant life forms was indicated. A conceptual model of early succession mechanisms is outlined and five basic mechanisms are identified (i.e. site availability, site suitability, availability of diaspores, strategies of colonizing species and biotic interactions). Their respective importance in three different stages of early succession is estimated and compared. The predictability of vegetation dynamics at each stage is rated differently.     

An experimental study of old-field succession in relation to different environmental factors

From 1984 to 1986, old-field succession on sterilized sand and loam was studied under different water- and nutrient regimes. Within one month, moss and phanerogam species appeared on all experimental plots but further succession was rather varied. Salix species established quickly on loam and formed within 3 years a shrub layer up to 3 m in height. On sand, woody plant species were observed only at a high ground-water level. On loam, the well-known old-field succession from short-living therophytes to long-living phanerophytes of clearings and woodlands proceeded very quickly. In contrast, on sand, therophytes, hemicryptophytes and herbaceous chamaephytes of ruderal- and grassland communities were still dominant after three years. A high ground-water level as well as mineral fertilization had sometimes positive, sometimes negative effects on this succession. Periodic estimates of cover, made during the succession were supplemented at the end of the experiment by the measurements of phytomass and bioelement storage. The highest amount of biomass was measured on the three loamy soils where shrub layers were well developed. In comparison with data published elsewhere, the above-ground biomass of 2.2–2.8 kg dry matter m^-2 and the below-ground biomass up to 7.2 kg dry matter m^-2 were both extraordinarily high. Over the three years, the vegetation on sandy soils accumulated between 1.2 and 5.1 g N m^-2 yr^-1 and on loamy soils between 17.1 and 24.7 g N m^-2 yr^-1.     

Colonization and early succession on anthropogenic soils

Abstract. This paper reports on vegetation development on permanent experimental plots during five years of succession. Nine (1 m²) plots were filled with three typical substrates from man-made habitats of urban and industrial areas in the region of Berlin. The three substrates (a commercial ‘topsoil’, a ruderal ‘landfill’ soil and a sandy soil), differ in organic matter and nutrient contents. Relevés of species composition and percent cover of each species present were made monthly during the growing season from the start of vegetation development. This paper describes the different successional pathways on topsoil and ruderal soil and the colonization process on sandy soil. On topsoil, ruderal annuals are dominant in the first year and are replaced by short-lived perennials from the second year. Those species were replaced by long-lived perennial herbs (Ballota nigra or Urtica dioica) from the third year of succession onwards. On the ruderal land-fill soil the early successional stages are less sharp and the perennial Solidago canadensis is able to dominate within one year after the succession was initiated. On sandy soil there is still an ongoing colonization process, where pioneer tree species like Betula pendula and Populus nigra play a main role. The importance of ‘initial floristic composition’, the role of substrate for community structure and the peculiarities of successional sequences on anthropogenic soils in the context of primary and secondary successions are discussed.     

Natural Establishment of Specialist Plant Species after Topsoil Removal and Soil Perturbation in Degraded Calcareous Sandy Grassland

Specialist plant species in calcareous sandy grasslands are threatened by acidification and high nutrient levels in the topsoil. We investigated whether topsoil removal and soil perturbation in degraded sandy grasslands could lead to establishment of specialist species belonging to the threatened xeric sand calcareous grassland habitat. Restoration actions performed in 2006 resulted in increased soil pH and reduced nitrogen availability. We found early colonisztion of the perennial key species Koeleria glauca after both deep perturbation and topsoil removal, and high seedling establishment in topsoil removal plots 5 and 6 years following the restoration treatment (2011–2012). After topsoil removal, overall vegetation composition in 2012 had developed toward the undegraded community, with target species accounting for 20% of the community after topsoil removal, compared to 30% in the undegraded vegetation, and less than 1% in untreated controls. Deep perturbation led to 7% target species, while there were almost no effects of shallow perturbation 6 years following treatment. These results demonstrate that topsoil removal can promote colonization of target species of calcareous sandy grassland and highlights the importance of considering the regeneration niche for target species when implementing restoration measures .     

Vegetation succession on reclaimed coal wastes in Spain: the influence of soil and environmental factors

Question: How is vegetation succession on coal mine wastes under a Mediterranean climate affected by the restoration method used (topsoil addition or not)? How are plant successional processes influenced by local landscape and soil factors? Location: Reclaimed coal mines in the north of Palencia province, northern Spain (42°47′‐42°50′ N, 4°32′‐4°53′ W). Methods: In Jun–Jul 2008, vascular plant species cover was monitored in 31 coal mines. The mines, which had been restored using two restoration methods (topsoil addition or not), comprised a chronosequence of different ages from 1 to 40 yr since restoration started. Soil and environmental factors at each mine were monitored and related to species cover using a combination of ordination methods and Huisman–Olff–Fresco modeling. Results: Plant succession was affected by restoration method . Where topsoil was added, succession was influenced by age since restoration and soil pH. Where no topsoil was added, soil factors seem to arrest succession. Vegetation composition on topsoiled sites showed a gradient with age, from the youngest, with early colonizing species, to oldest, with an increase in woody species. Vegetation on non‐topsoiled sites comprised mainly early‐successional species. Response to age and pH of 37 species found on topsoiled mines is described. Conclusions: Restoration of coal mines under this Mediterranean climate can be relatively fast if topsoil is added, with a native shrub community developing after 15 yr. However, if topsoil is not used, it takes more than 40 yr. For topsoiled mines, the species found in the different successional stages were identified, and their tolerance to soil pH was derived. This information will assist future restoration projects in the area.     

Topsoil Seed Bank of an Oak–Hickory Forest in Eastern Kentucky as a Restoration Tool on Surface Mines

Typical reclamation practices in the central Appalachian coal region often use compacted spoils as a topsoil replacement, and these soils are revegetated with aggressive grasses and legumes. This restoration approach results in an herbaceous‐dominated landscape with limited natural succession by native flora. An alternative restoration method is to save topsoil prior to mining, stockpile it during mining, and then replace it on uncompacted spoils to “inoculate” the site with native plant species. In an effort to test this approach, vegetation assessments were performed at a relatively undisturbed forested site in Clay County, Kentucky, U.S.A. Eight 15 × 15–m plots were established, and soils from individual plots were used in seed bank studies both in the greenhouse and on loose‐dumped mine spoils. Bulk soil samples were removed from the plots and subjected to cold stratification for 13 weeks, after which seeds were allowed to germinate under greenhouse conditions for 1 year. Additional topsoil (approximately 1.5 m³ from the upper 0–20 cm) was removed from the plots and replaced on fresh spoil in eight 2 × 5–m plots. Controls consisted of uncompacted spoil material substrate only. A total of 105 species emerged in the greenhouse from the seed bank. On the relocated topsoil, 69 species were recorded of which 39 were also observed in pre‐mine vegetation surveys. Ten of the 17 most important pre‐mine forested site species emerged from the relocated topsoil treatments on the mine site. Our results indicate that application of topsoil could enhance plant diversity and native species reestablishment on surface‐mined lands.     

Nitrogen accumulation in kaolin mining wastes in cornwall I. Natural communities

Summary Plant succession was investigated on sand waste heaps produced by kaolin mining in central Cornwall. It was found that relatively even aged, monospecific stands of vegetation were frequently present. The principal colonists were woody leguminous plants which, in some situations, were superceded by a massive growth of rhododendrons (Rhododendron ponticum) or native woodland species. Where legumes were absent, the waste was slowly colonised by Calluna vulgaris and other heathland species.The age structure of the vegetation was negatively and significantly correlated (r=–0.71) with the moisture deficit (evapotranspiration minus rainfall) during the spring and early summer. Drought, limited seed availability, and low nitrogen levels in the waste material are factors which contribute to the development of monospecific, even-aged legume communities of Ulex europaeus, Sarothamnus scoparius and Lupinus arboreus.Measurements were made of biomass and litter in five plant communities and nitrogen levels were determined in the soil/plant system within these communities and also in the soil of a woodland which had developed on sand waste. The low productivity and low rate of nitrogen accumulation in a stand of Calluna vulgaris contrasted with stands of the three woody legumes. Gorse (Ulex europaeus) accumulated nitrogen most rapidly and appeared to have preceded invasion by Rhododendron ponticum and transition to native woodland. Within the woodland and rhododendron thicket the soil nitrogen levels approached those characteristic of temperate climax woodland.The data indicate that the course of plant succession and the rate of soil development are strongly influenced by the biological properties of the colonising species. These processes are accelerated considerably following the invasion of woody legumes. re]19760512Department of Botany Liverpool University     

Changes in the structure and heterogeneity of vegetation and microsite environments with the chronosequence of primary succession on a glacier foreland in Ellesmere Island, high arctic Canada

Primary plant succession was investigated on a well-vegetated glacier foreland on Ellesmere Island in high arctic Canada. A field survey was carried out on four glacier moraines differing in time after deglaciation to assess vegetation development and microsite modification in the chronosequence of succession. The results showed evidence of directional succession without species replacement, which is atypical in the high arctic, reflecting the exceptionally long time vegetation development. During this successional process, Salix arctica dominated throughout all moraines. The population structures of S. arctica on these moraines implied the population growth of this species with progressing succession. The population density of S. arctica reflected the abundance of vascular plants, suggesting that development of the plant community might be related to structural changes and the growth of constituting populations. Through such growths of the population and the whole community with progressing succession, the spatial heterogeneity of vegetation gradually declines. Moreover, this vegetation homogenization is accompanied by changes in the spatial heterogeneity of microsite environments, suggesting significant plant effects on the modification of microsite environments. Accordingly, it was concluded that the directional primary succession observed on this glacier foreland is characterized by the initial sporadic colonization of plants, subsequent population growths, and the community assembly of vascular plants, accompanied by microsite modification.     

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.