Species Composition Of Soil Seed Bank Research Articles

Soil seed bank composition and aboveground vegetation in dry Afromontane forest patches of Northwestern Ethiopia

The species composition in the aboveground vegetation and soil seed bank (SSB) were described for the dry Afromontane forest patches of Northwestern Ethiopia. Plots (30 × 30 m) were established to collect the vegetation and environmental data. Soil samples were collected for the soil bank study from the small plots measuring 10 cm × 10 cm from four soil layers. Shannon Weiner index and evenness were used to assess the species diversity and richness of the forest. Density, DBH, basal area, frequency, and importance value indices (IVI) of woody species were computed to characterize the vegetation structure of the forest. Results indicate the presence of 176 plant species belonging to 80 families. The Shannon diversity index and evenness values of the study area were 2.79 and 0.95, respectively were medium, compared to other dry Afromontane forests of Ethiopia. The total basal area and density of woody species were 51.42 m2 ha−1 and 2679.33 individual ha−1, respectively. The most dominant species as and indicated by their important value index (lVI) was Prunus africana (17.97). A total of 2133 seedlings belonging to 44 species and 27 families were identified from the soil seed bank, with a viable seed density of 4636.95seeds/m2. The species composition of the seed bank was dominated by 29 herb species (65.9%) compared to 2 tree species, which accounted for only 4.54% of the total number of species. The highest number of species density was recorded in the litter and the upper 3 cm layer of the soil and gradually decreased with increasing depth. The Similarity between soil seed bank species composition and aboveground vegetation was low and conclude that the regeneration potential of the forest from seed bank is limited. Redundancy analysis (RDA) showed that emerged seedlings from the soil seed bank were significantly influenced by elevation and soil cation exchange capacity. The natural regeneration process of soil seed bank should be assisted through transplanting indigenous tree species in to the forests to accelerate the restoration of the vegetation and conservation and sustainable utilization of the reaming of forest patches is a necessity.

Soil seedbank: Importance for revegetation in the water level fluctuation zone of the reservoir area

Vegetation succession in the water level fluctuation zone (WLFZ) is driven by periodical water fluctuations, the mechanisms of response and synergistic evolution between aboveground vegetation (AGV) and soil seed bank (SSB) in the WLFZ remain unclear. To illustrate the response between AGV and SSB and the importance of SSB for revegetation in the WLFZ, the Three Gorges Reservoir (TGR) was taken as the target in the current study, and five sampling sites that lie in the center of reservoir and major tributaries of the TGR were selected. Plant community survey along the three water level gradients (i.e., 165–170 m, 170–175 m and 175–180 m) was conducted. Simultaneously, SSB samples on the topsoil (0–5 cm) were collected for germination experiments. A total of forty-nine species were observed from the SSB, belonging to 24 families and 47 genera, of which Asteraceae (8 species) and Poaceae (6 species) dominated. The number of total germinated seedlings species from soil samples from the sampling sites differed, i.e., was lower in Fengjie and Wushan compared to Yunyang, Gaoyang and Fengdu. The seed density in 165–170 m was significantly lower than that of 170–175 m and 175–180 m (p < 0.05). The Sørensen similarity coefficients between AGV and SSB tended to decrease with the increase of water level gradient, ranging from 0.04 to 0.42. SSB species composition was significantly associated with total carbon and total nitrogen contents of the soil (both p < 0.05). The SSB density was significantly negatively correlated with concentration of soil total nitrogen (p < 0.05), the species richness of SSB was significantly negatively correlated with soil pH value (p < 0.05). Hence, the relationship between the SSB and the soil habitat might be an important factor driving the construction of vegetation in the WLFZ. The correlation between dynamic of SSB and TGR hydrological regimes should be considered for revegetation in the WLFZ.

Effects of exotic plantation expansion and management intervention on woody plant species diversity, regeneration and soil seed bank in Tarmaber district, Ethiopia

This study was carried out to determine the effect of plantation forest with management intervention on woody plant species diversity in Tarmaber district north shewa zone Ethiopia, regeneration and soil seed bank species composition in five different forest types. A total of 75 circular sample plots of 314 m2 were established along a transect lines. Soil seed bank analysis was done from soil samples collected in each of the plots (225 samples). Different diversity index and ANOVA was used in SPSS software for analysis. The result showed that a total of 51 woody plant species was recorded in adjacent natural forest (41), managed C. lusitanica (27), not managed C. lusitanica (9), managed E. globules (22) and not managed E. globules (13) species. Regeneration of seedlings were 3538, 5567, 707, 1462 and 2524 mean stems ha-1 for natural forest, managed C. lusitanica, not managed C. lusitanica, managed E. globules and not managed E. globules respectively. Unmanaged C. lusitanica plantations had significantly lower densities of mature tree stems ha-1 as compared to managed C. lusitanica, managed E. globules and adjacent natural forest (F=14.03, p&lt;0.05). Similarly in terms of sapling density ha-1 unmanaged C. lusitanica was significantly lower from other forest types (F=7.37, p &lt;0.05). However managed C. lusitanica had significantly higher seedling regeneration (stem density ha-1) than other plantation and adjacent natural forests (F = 16.11, p &lt; 0.05). Generally mean stem densities including tree, sapling and seedling of woody species among different forest types managed C. lusitanica was significantly higher among different forest types (F= 13.01, p&lt;0.05). From the soil seed bank a total of 22 plant species (20 native and 2 exotic) species were recovered. In different forest types the number of species recorded was in adjacent natural forest (19), managed C. lusitanica (11), unmanaged C. lusitanica (4), managed E. globules (7) and unmanaged E. globules (5). Generally, with appropriate management intervention, undergrowth vegetation and soil seed bank status in plantation forest had good species composition and diversity.

Effects of Exotic Plantation and Management Intervention on Woody Plant Species Diversity, Regeneration and Soil Seed Bank in Tarmaber District, Ethiopia

Plantations have many economic and environmental benefits, but exotic plantations are widely viewed negatively mainly in relation to biological diversity conservation, and regenerations to prove this dilemma this study is necessary. This study was carried out in Tarmaber district north shewa zone Ethiopia to determine the effect of plantation forest with management intervention on woody plant species diversity, regeneration and soil seed bank species composition in five different forest types. A total of 75 circular sample plots of 314 m² were established along a transect lines. Soil seed bank analysis was done from soil samples collected in each of the plots (225 samples) to examine the similarity between the soil seed bank and aboveground flora. Different diversity index and ANOVA was used in SPSS software for analysis. The result showed that a total of 51 woody plant species was recorded in adjacent natural forest (41), managed <i>C. lusitanica</i> (27), not managed <i>C. lusitanica</i> (9), managed <i>E. globules</i> (22) and not managed <i>E. globules</i> (13) species. Regeneration of seedlings were 3538, 5567, 707, 1462 and 2524 mean stems ha^-1 for natural forest, managed <i>C. lusitanica</i>, not managed <i>C. lusitanica</i>, managed <i>E. globules</i>and not managed <i>E. globules</i>respectively. Unmanaged <i>C. lusitanica</i>plantations had significantly lower densities of mature tree stems ha^-1 as compared to managed <i>C. lusitanica</i>, managed <i>E. globules</i>and adjacent natural forest (F=14.03, p<0.05). Similarly in terms of sapling density ha^-1 unmanaged <i>C. lusitanica</i> was significantly lower from other forest types (F=7.37, p <0.05). However managed <i>C. lusitanica</i>had significantly higher seedling regeneration (stem density ha^-1) than other plantation and adjacent natural forests (F = 16.11, p < 0.05). Generally meanstem densities including tree, sapling and seedling of woody species among different forest types managed <i>C. lusitanica</i> was significantly higher among different forest types (F= 13.01, p<0.05). From the soil seed bank a total of 22 plant species (20 native and 2 exotic) species were recovered. In different forest types the number of species recorded was in adjacent natural forest (19), managed <i>C. lusitanica</i> (11), unmanaged <i>C. lusitanica</i> (4), managed E. globules (7) and unmanaged <i>E. globules</i> (5). The similarity of the soil seed bank was more or less similar to the above ground flora with maximum Sorenson’s similarity values of 0.633. Generally with appropriate management intervention undergrowth vegetation and soil seed bank status in plantation forest had good species composition and diversity.

Strategies to persist in the community: Soil seed bank and above‐ground vegetation in Patagonian pine plantations

AbstractQuestionsIn terms of biodiversity conservation, forest plantations are often considered problematic because they usually have negative effects on natural ecosystems. Soil seed banks could play an important role in restoring vegetation that was originally present, by recruiting species that have disappeared above‐ground. We addressed this topic in plantations located in the Patagonian steppe by asking the following questions: Are richness, abundance and composition of steppe above‐ground vegetation and soil seed bank affected by plantations? Is species composition of the above‐ground vegetation and soil seed bank similar in plantations and in the steppe?LocationNW of Chubut Province, Patagonia, Argentina.MethodsWe selected three plantations located in the steppe, and delimited three sectors: steppe, plantation edge and plantation interior. We compared richness and abundance by species origin and growth form among sectors for the above‐ground vegetation and soil seed bank compartments, using generalized linear mixed models. We compared species composition for each compartment and between them using permutational multivariate analysis of variance and non‐metric multidimensional scaling.ResultsIn above‐ground vegetation, we found a decrease in richness and abundance, and changes in composition from the steppe to the plantation interior. Richness and abundance of the soil seed bank did not show differences among steppe and the plantation sectors, although composition was different among them. Above‐ground vegetation and soil seed bank species composition were always different; native perennial herbs and shrubs were predominant in the above‐ground vegetation while exotic annual herbs dominated the soil seed bank.ConclusionsOur findings suggest that plant recruitment from the soil seed bank would not be sufficient for restoring depleted species pools in the above‐ground vegetation of plantations. Therefore, actions promoting native species reestablishment and control of exotics should be considered to reach the aim of restoring biodiversity in former plantations.

Relationship between the standing vegetation, soil properties and soil seed bank of an industrially degraded vegetation of Iron Smelting Factory

This study assessed the floristic composition, soil properties and the soil seedbank of the vegetation around the Iron smelting factory. This was with a view to determining the functional role played by soil chemical composition and the seed bank in the modifications of vegetation patterns. Five 100 m × 5 m plots were selected from the study site; vegetation, soil seed bank and some soil chemical parameters were assessed. One-way Analysis of Variance and Duncan multiple range tests were employed for data analysis. The results showed that the soil samples collected were slightly basic (or neutral) with the total Nitrogen in all the five plots ranged from 0.22 to 0.33%. There was a little contribution by woody species to the floristic composition of both the standing vegetation and soil seed bank. There was very low similarity (10.6% - 28.57%) between the standing vegetation and the soil seed bank species composition in the study site. The results of seedling emergence showed that herbaceous species dominated the soil seed bank compared to other life forms. Our result revealed a shift between seed-bank and vegetation composition which could be a consequence of the soil chemical properties and also as a result of different level of disturbance occurring due to the citing of industry in the area. Keywords : Emergence, nutrient cycling, regeneration, soil properties, soil seed bank, standing vegetation.

The influence of Pechuel-Loeschea leubnitziae (wild sage) on grass sward and soil seed bank composition

Soil seed banks provide not only a historical record of vegetation composition but also the potential for post-disturbance revegetation. Pechuel-Loeschea leubnitziae (wild sage) is a multistemmed, aromatic shrub, occurring in Namibia, Botswana, Swaziland, Zimbabwe and the northern regions of South Africa, that colonises disturbed regions on sandy, alkaline soils. The influence of differing levels of P. leubnitziae cover on soil seed-bank characteristics and aboveground herbaceous species composition was determined by examining aboveground species composition, recorded in the field, and soil seed-bank species composition, determined by recording germinations from topsoil samples collected at each of 104 sites in the southern Okavango Delta. No correlation was observed between aboveground and soil seed-bank composition (p = 0.209). Cover of P. leubnitziae did not affect soil seed-bank species composition (p = 0.31) or the grass:non-grass ratio within the seed bank (p = 0.308). It did, however, affect aboveground grass composition (p = 0.018), with increasing P. leubnitziae cover associated with increasing abundance of poor-quality, shade-tolerant grass species. This confirms the observations that encroachment of P. leubnitziae may be associated with a decrease in veld quality and carrying capacity, and highlights the necessity for further study to facilitate a better understanding of the species for management purposes.

Seasonal variation in seed bank composition and its interaction with nutrient enrichment in the Everglades wetlands

In the Florida Everglades, nutrient enrichment from agricultural outflow and the change in hydrology have collectively contributed to the expansion of cattails ( Typha spp.). To assess the effectiveness of prescribed fire in controlling cattails and to predict vegetation dynamics after the fire, it is important to understand the seasonal variation of the soil seed bank and how the seed bank is affected by nutrient enrichment and fire. This paper investigates the effects of season, nutrient enrichment, and fire on soil seed bank species composition, richness, and density along a nutrient gradient in Water Conservation Area 2A (WCA 2A) of the Florida Everglades. Species richness was significantly affected by nutrient enrichment and season but not their interaction. Total seed density, however, was significantly affected by the interaction between nutrient enrichment and season. Yet, at species level, the relationship between seed density, nutrient enrichment and season varied. The highest seed density of cattail occurred in summer at highly enriched sites, but that of sawgrass occurred in fall regardless of enrichment; the seed density of water lily was very low regardless of season and nutrient enrichment, and the highest Amarathus seed density occurred at highly enriched sites year round. Moreover, germination timing differed greatly among species. While cattail seeds had a short incubation period and started to germinate 2–3 days after initiation of the germination assay, sawgrass seeds generally started to germinate 4 weeks later. Further, both the prescribed summer fire at the highly enriched site and the natural winter fire at the moderately enriched site reduced the seed density of cattail but not of sawgrass. Our results suggest that fire application for vegetation recovery in WCA 2A would benefit from explicitly considering seasonal dynamics of the seed bank.

Variation in soil seed bank species composition of a dry coniferous forest: spatial scale and sampling considerations

In order to assess the effects of disturbance on soil seed bank spatial structure, variation in seed bank species composition was analyzed at two spatial scales in mature (undisturbed) and recently disturbed stands of Interior Douglas-fir forest in south-central British Columbia. Coarse-scale analysis among stands 10–100 km apart using Multi-Response Permutation Procedures showed that individual mature stands were mainly characterized by unique seed bank species compositions. Disturbance had an homogenizing effect on seed bank species composition at the coarse scale––there was less variability among stands following disturbance by both low and high severity fires, and by non-salvage logging. In contrast, finer scale analysis among sampling units c. 10 m apart showed that heterogeneity in seed bank species composition was greater on severely burned and logged sites, commensurate with greater levels of soil disturbance, than on lightly burned and undisturbed sites. Despite the high intensity of seed bank sampling (sixty 25 cm2 soil samples from each of 16 sites), species-area curves leveled off only when infrequent species were removed from the dataset. The number of seed bank samples required to account for the common species ranged from 84 on severely burned sites, to 196 on undisturbed sites; more than the 240 samples collected per disturbance class in this study would have been required to account for the remaining infrequent species. Overall, this study highlights the importance of sampling intensively within multiple stands to capture the variation in species composition inherent to these dry coniferous forest soil seed banks.

Soil seed banks in Pinus ponderosa forests in Arizona: Clues to site history and restoration potential

AbstractQuestion: How does the relationship between the viable soil seed bank species composition and the above‐ground vegetation in northern Arizona Pinus ponderosa forests differ under varying historical land use disturbances (low, intermediate, high)? Is above‐ground vegetation correlated to the viable soil seed bank immediately following soil disturbance from restoration thinning treatments?Location: Northern Arizona, USA.Methods: Soil seed bank samples were taken along replicated transects and collected with a 5‐cm diameter bulk density hammer. Samples included a 5 ‐cm diameter O‐horizon sample (at varying depths) plus the underlying mineral soil to a depth of 5 cm. The seedling emergent method was used to quantify seed bank species composition and density. The herbaceous and shrub plant community was quantified along the same transects using the point intercept method.Results: Early‐successional or ruderal species were common in the soil seed bank at all three disturbance sites. Non‐native species, notably Verbascum thapsus, were more numerous (up to 940 seeds/m2) under high disturbance with overgrazing and logging, and less common or absent under low disturbance. Most viable seeds were found in the O‐horizon and the upper 5 cm of mineral soil; there was little correlation between species in the soil seed bank and the above‐ground vegetation.Conclusions: We recommend that restoration plans be geared toward minimizing activities, such as severe soil disturbance, that may promote the spread of non‐native invasive species, and that manual seeding be explored as an option to restore plant species diversity and abundance.

The germinable soil seedbank of Eucalyptus victrix grassy woodlands at Roy Hill station, Pilbara district, Western Australia

The paper reports soil seedbank species composition, of Eucalyptus victrix grassy woodlands, of the upper Fortescue River in the Pilbara District, Western Australia. In this study, our objectives were to investigate germinable soil seedbanks and species composition in response to three simulated seasons, using emergence. Variation in seed density from three depths was tested. Four field sites were sampled. Thirty samples were collected in late spring, after seed rain and before summer rainfall. From each sample spot, three soil depths (surface, 1–5, and 6–10 cm) were segregated from beneath surface areas of 100 cm2. Samples were later incubated in a glasshouse to simulate three different seasonal conditions (autumn, winter and spring). Germinating seedlings were recorded on emergence and grown until identified. Forty-one species germinated, comprising 11 grasses (7 annuals and 4 perennials), 25 annual herbs and 5 perennial herbs. Distribution patterns of germinable seed in both the important annual grass Eragrostis japonica and the perennial Eragrostis setifolia (a preferred cattle fodder species), suggest that seedbank accumulation differs among species and between sites. In part, this may be associated with the absence of grazing. Species with most total germinable seed were E. japonica (Poaceae; 603/m2), and the annual herbs Calotis multicaulis (Asteraceae; 346/m2), and Mimulus gracilis (Scrophulariaceae; 168/m2). Perennial grass seed was sparse. Spring simulation gave most germination (1059), followed by autumn (892) and winter (376) sets. Greatest species diversity was produced from the spring simulation (33 species), followed by autumn (26), and winter (22). Of the total germination, 92% came from 17 species that were represented in all three simulations. Of the 1227 grass seedlings counted, most were recruited from the surface soil (735), followed by the 5 (310) and 10 (182) cm depths. Marginally more grass seedlings germinated from the spring simulation (558) than the autumn set (523). Only 11.9% of grass germinants came from the winter simulation. All grass species recruited from the soil seedbanks had a C4 photosynthetic pathway. Except for Cenchrus ciliaris all grass species are native to Australia. Of the four sites sampled, one fenced to exclude cattle five years earlier had significantly more germination than the three unfenced sites. Seedbank sampling produced several new records for plants in the areas sampled.

Effects of a copper smelter on a grassland community in the Puchuncavı́ Valley, Chile

A grassland formation has been subjected to pollution generated by the Ventanas copper smelter since 1964 (Puchuncavı́ Valley, central zone of Chile) with extensive damage to local vegetation and important changes in soil characteristics. The aims of the study were (1) to detect soil parameters that best explain changes observed in plant species richness and abundance and (2) to determine if pollution-derived stresses have also affected regeneration capabilities of plant communities from the soil seed bank. The grassland was quantitatively analysed in terms of physico-chemical soil characteristics, plant species diversity and abundance, and soil seed bank species composition and abundance. Results showed that a decrease in total soil nitrogen explained 13% of the changes detected in plant abundance while soil pH and 0.05 M EDTA extractable copper explained 10% and 7%, respectively, of the vegetation change. It was also found that the pollution has already affected plant species regeneration capabilities from the soil seed bank and the microsite distribution of the seeds in soils.