scholarly journals Zróżnicowanie banków nasion w naturalnie i antropogenicznie przekształconych zbiorowiskach leśnych [Diversity of soil seed banks in natural and man-modified forest communities]

2014 ◽  
Vol 88 ◽  
pp. 1-147 ◽  
Author(s):  
Małgorzata Jankowska-Błaszczuk

The objective of the study was to reveal diversity in species composition and size of soil seed banks derived from forest communities undergoing different intensity of human impact as well as to show the seed bank strategy as an adaptation of species to many kinds of disturbances occurring in natural deciduous forests. On the basis of the study of soil seed bank in natural, stabilised deciduous forest communities in Białowieża National Park and taking into account data from literature it was found that: (1) Densities of seed banks of fertile, undisturbed deciduous forest vary from three to eight thousand seeds per one m<sup>2</sup>. The majority of these seeds (60–80%)come from the herb layer. Persistance of such banks do not exceed a few years. Species which arę dominant in seed bank of such forest are characterized by mean light requirements. The impulses which break their secondary dormancy arę slight disturbances in the herb layer. (2) Species structure of seed bank derived from such forest does not reflect floristic composition of the herb layer because this layer is dominated by species whose survival strategy is connected with vegetative propagation. (3) In seed banks of even very stable forest communities there are species which are absent from the herb layer of the forest. The species need light gaps in trees canopy for establishment. They are very light demanding and persistent in soil. Percentage of these species in soil seed banks grows with the intensity of human impact on forest communities. These species dominate also in seed banks of relatively natural forests but small and surrounded by meadows and fields. Seedlings of these species occur spontanously during the first phase of regeneration of forest gaps. After the canopy close-up, the species disappear from cover vegetation but their numerous and very persistant seeds wait in soil seed bank for the next disturbance.

2014 ◽  
Vol 67 (3-4) ◽  
pp. 313-324 ◽  
Author(s):  
Małgorzata Jankowska-Błaszczuk

Using the germination method, the species diversity, density of the soil seed bank and its relation to cover vegetation in a natural deciduous forest with primary and secondary tree stand were compared. It was found that the mean density and species composition of the soil seed bank in the forest with secondary tree stand that has spontaneously been overgrown over the last 90 years after clear-cutting does not differ from the soil seed bank derived from primeval forest (3167M<sup>-2</sup> vs. 3827m<sup>-2</sup>). In both stands there were 46 species altogether and 36 were common and seed banks were dominated by herbs. The most abundant in this group were: <em>Urtica dioica</em>, <em>Chrysosplenium alternifolium</em>, <em>Geranium robertianum</em>, <em>Oxalis acetosella</em>. In both cases it was found that the species structure of the herb layer was similar to that of the seed bank in about 70%. The seed banks of species absent from the herb layer or present there only sporadically were much more abundant. The seedlings of these species constituted more than one third of all seedlings that emerged in the samples from the secondary tree stand and only 5% those from the primary one. The analysis of seed bank in heavily rooted places under primary and secondary tree stands showed that in places with a totally distroyed herb layer the density of the soil seed bank in primeval forest was three times lower than in places with fully developed herb layer structure (102.60±22.61 vs. 307.0±206.5 per sample). This difference under secondary tree stand turned out to be much lower (415.8±137.8 vs. 358.2±126.0 per sample).


2011 ◽  
Vol 79 (2) ◽  
pp. 157-166 ◽  
Author(s):  
Maciej Wódkiewicz ◽  
Anna Justyna Kwiatkowska-Falińska

Forest seed banks mostly studied in managed forests proved to be small, species poor and not reflecting aboveground species composition. Yet studies conducted in undisturbed communities indicate a different seed bank characteristic. Therefore we aimed at describing soil seed bank in an undisturbed forest in a remnant of European lowland temperate forests, the Białowieża Forest. We compared similarity between the herb layer and seed bank, similarity of seed bank between different patches, and dominance structure of species in the herb layer and in the seed bank of two related oak-hornbeam communities. We report relatively high values of Sorensen species similarity index between herb layer and seed bank of both patches. This suggests higher species similarity of the herb layer and soil seed bank in natural, unmanaged forests represented by both plots than in fragmented communities influenced by man. Although there was a set of core seed bank species present at both plots, yielding high Sorensen species similarity index values, considerable differences between plots in seed bank size and dominance structure of species were found, indicating spatial variability of studied seed bank generated by edaphic conditions. Dominance structure of species in the herb layer was not reflected in the underlying seed bank. This stresses, that natural forest regeneration cannot rely only on the seed bank, although some forest species are capable of forming soil seed banks. While forest seed banks may not reflect vegetation composition of past successional stages, they may inform on history and land use of a specific plot.


Author(s):  
Ya-Fei Shi ◽  
Zengru Wang ◽  
Bing-Xin Xu ◽  
Jian-Qiang Huo ◽  
Rui Hu ◽  
...  

Soil seed banks may offer great potential for restoring and maintaining desert ecosystems that have been degraded by climate change and anthropogenic disturbance. However, few studies have explored the annual dynamics in the composition and relative abundance of these soil seed banks. We conducted a long-term observational study to assess the effects of environmental factors (meteorology and microtopography) and aboveground vegetation on the soil seed bank of the Tengger Desert, China. The desert seed bank was dominated by annual herbs. We found that more rainfall in the growing season increased the number of seeds in the soil seed bank, and that quadrats at relatively higher elevations had fewer seeds. The species composition had more similarity in the seed bank than in the aboveground vegetation, though the seed bank and aboveground vegetation did change synchronously due to the rapid propagation of annuals. Together, our findings suggest that the combined effects of environmental factors and plant life forms determine the species composition and size of soil seed banks in deserts. Thus, if degraded desert ecosystems are left to regenerate naturally, the lack of shrub and perennial herb seeds could crucially limit their restoration. Human intervention and management may have to be applied to enhance the seed abundance of longer-lived lifeforms in degraded deserts.


2020 ◽  
Vol 13 (3) ◽  
pp. 256-265 ◽  
Author(s):  
José Djalma de Souza ◽  
Bruno Ayron de Souza Aguiar ◽  
Danielle Melo dos Santos ◽  
Vanessa Kelly Rodrigues de Araujo ◽  
Júlia Arruda Simões ◽  
...  

Abstract Aims In dry tropical forests, herbaceous species may have dormancy mechanisms and form persistent and transient seed banks in the soil. Evolutionarily acquired, these mechanisms are efficient for the establishment and survival of these herbs, especially in forests with unpredictable climates, such as the Caatinga. Thus, our objective was to verify whether the studied herbaceous species adopt the physical dormancy mechanism and how these natural barriers are overcome, to understand the temporal dynamics existing in the soil seed bank from a Brazilian dry tropical forest. Methods Seeds of five native herbaceous species from the Caatinga forests were selected and submitted to pre-germinative treatments for verifying the presence of physical dormancy. We collected soil samples in the rainy and dry seasons for four consecutive years and monitored the emergence of the selected herbaceous in the greenhouse. We verified the differences in germination and seed bank emergence in the soil by generalized linear models. Important Findings The presence and absence of physical dormancy were observed in seeds from Caatinga herbaceous species. We found intraspecific and interspecific differences in the herbaceous emergence from soil seed banks between years and climatic seasons. In perennial herbs, consecutive lack of emergence between seasons and years was frequent, which suggests a direct relationship with the mechanism of physical dormancy and the environmental conditions necessary to overcome integument barriers. In these species, seed dimorphism and dormancy may confer additional advantages to their survival. Moreover, presenting intermediate levels of physical dormancy in an annual species may be an evolutionary adjustment to rainfall unpredictability. In contrast, we found that the annual herb without dormancy is more sensitive to seasonal and interannual climate changes, as evidenced by the increase and significant reduction of its emergence in the soil seed bank. These differences acquired evolutionarily are advantageous for the establishment of herbaceous populations, mainly in semiarid regions with an unpredictable climate.


1990 ◽  
Vol 38 (3) ◽  
pp. 261 ◽  
Author(s):  
AW Graham ◽  
MS Hopkins

The size and floristic composition of soil seed banks under four adjacent, unlogged and structurally different rainforest types were assessed by exposing 17 surface soil samples (to 40mm depth) to germination-house conditions. The mean size of the seed bank in the undisturbed forest types was 240 seeds m-2 (s.d. 139). Seeds of secondary species dominated the soil seed banks in all forest types, although weed seeds constituted only 0.6-4.0%. Some forest types had characteristic component secondary species in the buried seed bank. Agglomerative classification and multidimensional scaling analysis of quantitative sample data indicated that the parent structural-environmental forest type was the dominant influence in determining composition of the soil seed banks. Comparisons of the seed banks of the intact rainforest with those of nearby disturbed forests showed the former to be 35 to 50% smaller in total size, and lacking in some distinctive secondary species. It was concluded that disturbance, both within and adjacent to rainforest, may influence soil seed bank compositions, and hence future patterns of regeneration.


2003 ◽  
Vol 51 (3) ◽  
pp. 227 ◽  
Author(s):  
Y. Tang ◽  
S. L. Boulter ◽  
R. L. Kitching

Physical changes and flows of energy at the interface between two contrasting ecosystems affect the distribution of species across the ecotone. The maintenance and stability of the, often abrupt, transition between Australian rainforest and non-rainforests is often attributed to fire. We use pre-germination treatments of smoke and heat on soil seed bank samples to determine plant distributions across the edge between subtropical rainforest and an adjacent eucalypt-dominated wet sclerophyll forest. Soil seed bank collections at 15 m within the eucalypt forest had both significantly higher density and diversity of seedlings than those at 30 m, at the edge itself or at any site within the rainforest. This response was most apparent when a pre-germination smoke treatment was applied. We suggest that smoke is an important germination trigger for species regenerating at this interface. Our results confirm the importance of fire in determining and maintaining the nature of this ecotone.


2011 ◽  
Vol 39 (1) ◽  
pp. 96 ◽  
Author(s):  
Altıngül ÖZASLAN PARLAK ◽  
Ahmet GÖKKUŞ ◽  
Hasan Can DEMİRAY

The composition and conservation of plant communities is greatly influenced by the soil seed bank. Information on the soil seed banks and the remaining vegetation in these ecosystems is crucial for guiding the restoration efforts. This study examines the size, species richness, diversity, uniformity, and similarity of soil seed banks and aboveground vegetation in 6 different grazing lands including coastal pasture, reseeded pasture, artificial pasture, lowland shrubland, ungrazed pasture, and hillside shrubland. Forty-eight soil samples were taken by cores with a diameter and depth of 10 cm from each of grazing lands in August of 2007. A vegetation survey was conducted using a 0.5 x 0.5-m quadrant in both the spring and fall. Eighty species were observed in soil seed banks and aboveground vegetation. The largest seed bank was observed in reseeded pasture (7,715 seed/m2), while the smallest seed bank was found in coastal pasture (2,755 seed/m2). Coastal pasture also possessed the least amount of aboveground vegetation (131 plants/m2). The most aboveground vegetation was found in ungrazed pasture (155 plants/m2). The most common species in seed banks were annual and perennial grasses in reseeded pasture, annual forbs in artificial pasture and hillside shrubland, and perennial forbs in low shrubland and ungrazed pasture. Species richness, diversity, and uniformity in seed banks were highest in lowland shrubland and lowest in artificial pasture. The seed bank and aboveground vegetation were similar in ungrazed pasture, coastal pasture, reseeded pasture, low shrubland, hillside shrubland and artificial pasture. Shrublands play an important role in species richness and the number of germinated seeds from seed banks of grazing lands in southern Marmara. The results showed that reseeding or a decrease in grazing pressure may improve the condition of grazing lands.


1997 ◽  
Vol 7 (3) ◽  
pp. 281-292 ◽  
Author(s):  
Małgorzata Jankowska-Błaszczuk ◽  
Peter J. Grubb

AbstractGermination over 3 years was followed in 25 soil samples of 31 × 31 × 5 cm each from primary and secondary stands in Białowieża forest, Poland. The number of seedlings emerging and the number of species declined over the 3 years. In year 1 the mean densities of emerging seedlings for the primary and secondary stands were similar (2142 m−2 and 2488 m−2 respectively); in year 3 the difference was greater (248 vs 498 m−2) but not statistically significant. The trend reflected the greater longevity of the seed bank species characteristic of the secondary forest. Two functional groups of herb and shrub species were distinguished in the seed bank based on (a) frequency as adults in the present vegetation, and (b) relative abundance in the seed banks of primary and secondary forest. Group A species need large-scale gaps in the tree canopy; most have very small seeds (<0.15 mg mean dry mass) and are very persistent in the soil. Group B species benefit from single-treefall gaps in the tree canopy, but appear to be suited primarily to gaps in the canopy of the herb layer and in the root layer made mainly by animals; their seeds are not as small (mostly >0.15 mg) and not as persistent in the soil. Group B species made up 86% of the seedlings emerging over 3 years in soil from the primary stand, and 56% of those from the secondary stand. In the laboratory all five Group B species tested showed some inhibition of germination in darkness, but only one showed unequivocal inhibition by far-red-enrichment of low irradiance light.


2011 ◽  
Vol 21 (2) ◽  
pp. 103-116 ◽  
Author(s):  
Ana Salazar ◽  
Guillermo Goldstein ◽  
Augusto C. Franco ◽  
Fernando Miralles-Wilhelm

AbstractA large fraction of tree species forming persistent soil seed-banks and with dormant seeds are expected to be found in strongly seasonal ecosystems such as Neotropical savannas, where seedling recruitment could be highly variable. In the savannas of Central Brazil, we studied seed characteristics (type of dormancy, longevity and moisture content) of 14 representative woody species differing in seed dispersal season. We also studied the dynamics of soil seed-banks and similarity patterns in woody species composition among seed rain, soil seed-bank, seedling bank and standing vegetation along shallow topographic gradients that differ in canopy cover. Woody species composition of the soil seed-bank largely differed from the standing vegetation, the seed rain and the seedling bank species composition, suggesting low recruitment of woody species from the soil seed-bank. Seeds of the 14 woody species remained viable for less than 16 months in laboratory dry-storage conditions. Of those, most seeds dispersed in the dry season were dormant and exhibited low moisture content, while most seeds dispersed in the wet season were non-dormant and exhibited high moisture content. Longevity of these seeds dispersed in the dry and the wet seasons did not differ significantly. This study shows that both timing of seed dispersal and dormancy appear to control timing of seed germination and seedling recruitment of most Neotropical savanna woody species, which did not form persistent soil seed-banks. This study contributes to the understanding of tree/grass coexistence and tree density variations along topographic gradients in tropical savannas.


2014 ◽  
Vol 24 (4) ◽  
pp. 315-320 ◽  
Author(s):  
Ricardo Álvarez-Espino ◽  
Héctor Godínez-Álvarez ◽  
Rodolfo De la Torre-Almaráz

AbstractThe soil seed bank is the reserve of viable seeds found in the soil. This reserve contributes to plant population persistence in unpredictable environments; thus, determining its presence is basic to understanding recruitment patterns and population dynamics. Studies of soil seed banks in the Cactaceae are scarce, although these plants are ecologically dominant in American arid and semi-arid environments. Most studies have inferred the presence of seed banks by analysing morphological seed traits or germination of seeds stored in the laboratory for different periods of time. Few studies have determined their presence through evaluation of distribution, density and longevity of seeds in the field. To fill this information gap, we determined the existence of, and studied, the soil seed bank ofStenocereus stellatus, a columnar cactus endemic to central Mexico. This study reports the evaluation of these characteristics in the field and discusses whether this species forms a soil seed bank. We found a higher number of seeds under shrubs than in areas lacking vegetation. Recently dispersed seeds did not germinate because they have primary dormancy. This dormancy was broken after 6 months of burial in the soil. Seeds buried for 10 months entered secondary dormancy and they were not viable at 24 months, probably because of pathogen attack. Considering dormancy and seed longevity, we suggest thatS. stellatushas the potential to form a short-term persistent seed bank. However, this should be confirmed by conducting studies on otherS. stellatuspopulations throughout their geographical distribution.


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