Wyniki wyszukiwania - Biblioteka Nauki

1

A non-soil seed bank dependent on the size of clonal plants: the case of Carex cespitosa, a guerrilla species in an unknown meadow

100%

Borkowska L. , Lembicz M. , Kasprzykowski Z.

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2017

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tom 65

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nr 2

EN

Long-lived clonal plants provide an optimal place for the natural storage of seeds as a ‘non-soil seed bank’. We tested the hypothesis that the size and species diversity of a non-soil seed bank deposited within the clonal plant Carex cespitosa depends mainly on the plant's size. To verify this hypothesis, an experiment was conducted on an unmown meadow in the Białowieża National Park. The emerging seedlings of different species originating from C. cespitosa tussocks of different size (large and small) were observed under greenhouse conditions for four years. The size of a non-soil seed bank was evaluated based on the number of seedlings. Significant differences in the seedling number were found between large and small sedge tussocks (Mann-Whitney test Z = 3.96, P < 0.001). However, the number of recorded species was independent of tussock size. Both types of tussocks were dominated by meadow, forest and swamp species (in decreasing order). Some of these species are no longer present in the studied area, or their occurrence is limited to small groups at the meadow's edges. A non-soil seed bank within the tussock cores of C. cespitosamay be, similar to a soil seed bank, a tool for studying the changes occurring in plant communities.

2

Seed banks and forest recruitment after disturbance: the composition and abundance of seed after clear-cut of stone pine (Pinus pinea L.) plantations

84%

Arduini I. , Orlandi C. , Mariotti M. , Masoni A.

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2013

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tom Vol. 61, nr 3

457--470

EN

Seed banks play a key role in the recruitment of forest vegetation after severe disturbance, but can originate an undesired plant community. Thus, investigations on seed bank structure, and early changes occurring after clear cut, are of primary interest for sustainable forest management. Researches were carried out in two mature stone pine (Pinus pinea L.) plantations located in Tuscany (Italy), along the Mediterranean coast. Soil samples were collected in March, July and October of the 2nd and 3rd year after clear-cut, in cut strips and adjacent intact stands. Seed bank size and composition were evaluated through the number of seedlings and species emerged from soil samples. Intact plantations differed in seed bank richness and composition, but not in abundance that was approximately 1,200 seeds m-2. Clear-cut doubled seed density in soil, did not change seed bank richness, and affected markedly composition. Seed banks of cut strips were richer in annual and open space species, and poorer in perennial, forest and disturbed sites species. Seeds of Erica scoparia dominated the seed bank, with a relative abundance of 60% in intact stands and 43% in cut strips. Proportion of annual seeds was slightly less than 20% in intact stands, but increased up to 50% after clear-cut. Between the 2nd and 3rd year from clear-cut, the proportion of seeds from species typical of stone pine forests decreased, while that of non-forest species and aliens increased. The scarcity of seeds from most forest species and the lack of tree seeds make the recruitment of understorey vegetation from seed banks critical. In addition, the increased seed density of alien and disturbed site species in intact seed banks with time from clear-cut, suggests that disturbance caused by cutting in narrow strips threatens the integrity of intact plantations.

3

The pattern of seed banks during secondary succession on poor soils

84%

Kwiatkowska-Falinska A. , Jankowska-Blaszczak M. , Wodkiewicz M.

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2011

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tom 80

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nr 4

EN

Studies on the soil seed banks of fallow lands of different ages were carried out on poor soil abandoned fields and in a fresh coniferous forest in north-eastern Poland. The size and diversity of seed banks was studied with the seedling emergence method. Species abundance (i), density (ii), number of species from different biological groups (iii) and distribution and mean LI value (iv) were analysed as the function of fallow land age. It was found that: (i) species diversity, number of species and ln of density are linear declining function of the fallow land age; (ii) for approx. 25 years the share of diaspores of identified species groups has been relatively similar. Seed banks of 40-50-year-old fallow lands are dominated by Calluna vulgaris, while the seed bank of the old fresh coniferous forest is dominated by dicotyledonous perennials and grasses; (iii) within the first 50 years of succession the persistence of seed banks measured by the Longevity Index increases gradually.

4

The potential role of nests of Black-billed Magpie Pica pica L. in accumulation and dispersal of seeds in agricultural landscape

84%

Czarnecka J. , Kitowski I.

Polish Journal of Ecology

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2008

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tom 56

|

nr 4

673-682

EN

The study aimed to describe the seed pool accumulated in the nest material of Magpie Pica pica, and to determine the importance of this mechanism of seed dispersal for such ecological processes as colonization of new habitats and expansion of alien plants. The seedling germination and seed extraction methods were used to determine seed abundance in the soil layer, the inner layer, and in the lining of 9 nests collected in three types of agricultural landscape: the first with domination of arable fields; the second with similar shares of arable fields and other landscape elements such as meadows of different types, shrubs, tree clumps and rushes; and the third with domination of lowland hay meadows. In all the nests, considerable numbers of diaspores were found (from 26 to 371 seeds per nest, belonging to more than 80 taxa). The main plant groups found in the nests are species connected with field roads, weeds and ruderal species, but also meadow and brushwood species were found there. The soil was gathered by birds from habitats with low vegetation cover and large areas of bare soil. Although the structure of seed pool of nests suggests that soil was mainly collected in the close vicinity of the nests’ future location, this mechanism of seed dispersal can probably be involved in long distance dispersal. Seeds of two rare kenophytes: Erucastrum gallicum (Willd.) O. E. Schulz and Diplotaxis tenuifolia (L.) DC were found in the material of nests localized more than 100 m away from their closest populations. It can be assumed that this mechanism of seed dispersal can play a potential role in the expansion of alien plants and colonisation of new habitats.

5

Seed banks and forest recruitment after disturbance: the composition and abundance of seed after clear-cut of stone pine (Pinus pinea L.) plantations

84%

Arduini I. , Orlandi C. , Mariotti M. , Masoni A.

|

tom 61

|

nr 3

EN

Seed banks play a key role in the recruitment of forest vegetation after severe disturbance, but can originate an undesired plant community. Thus, investigations on seed bank structure, and early changes occurring after clearcut, are of primary interest for sustainable forest management. Researches were carried out in two mature stone pine (Pinus pinea L.) plantations located in Tuscany (Italy), along the Mediterranean coast. Soil samples were collected in March, July and October of the 2nd and 3rd year after clear-cut, in cut strips and adjacent intact stands. Seed bank size and composition were evaluated through the number of seedlings and species emerged from soil samples. Intact plantations differed in seed bank richness and composition, but not in abundance that was approximately 1,200 seeds m–2. Clear-cut doubled seed density in soil, did not change seed bank richness, and affected markedly composition. Seed banks of cut strips were richer in annual and open space species, and poorer in perennial, forest and disturbed sites species. Seeds of Erica scoparia dominated the seed bank, with a relative abundance of 60% in intact stands and 43% in cut strips. Proportion of annual seeds was slightly less than 20% in intact stands, but increased up to 50% after clear-cut. Between the 2nd and 3rd year from clear-cut, the proportion of seeds from species typical of stone pine forests decreased, while that of non-forest species and aliens increased. The scarcity of seeds from most forest species and the lack of tree seeds make the recruitment of understorey vegetation from seed banks critical. In addition, the increased seed density of alien and disturbed site species in intact seed banks with time from clear-cut, suggests that disturbance caused by cutting in narrow strips threatens the integrity of intact plantations.

6

Ancient forest species and the diversity of vegetation and seed bank indicate the aptitude of transformed thermophilous oak wood patches for restoration

84%

Kwiatkowska-Falinska A. J. , Panufnik-Medrzycka D. , Wodkiewicz M. , Sondej I. , Jaroszewicz B.

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nr 1

EN

Thermophilous oak wood is the most species-rich forest habitat in the zone of mixed deciduous forests. A very limited amount of it has been saved in good condition. We investigated the principal hypothesis that the vegetation and seed banks, especially of the ancient forest species, are good indicators of habitat naturalness and its aptitude for restoration. Vegetation and seed bank sampling were carried out in fragments of forest with a known management and disturbance history over the past 80 years. We predicted that natural and anthropogenic transformations of tree stands would be significant factors shaping species composition and similarity of vegetation and seed banks. The closest similarity was observed between the seed banks of plots which were never logged. The least related to others was the seed bank of the logged site, whose soil was ploughed prior to tree replantation. The highest number of ancient forest species was recorded in the vegetation (33 species) and in the soil seed bank (21 species) of the least transformed patch of thermophilous oak forest. It was decreasing gradually with increase of the tree canopy cover on the research plots. Our results indicate also that the higher the coefficient of similarity between seed bank and vegetation, especially of the ancient forest species, the higher the forest’s naturalness. We conclude that restoration of thermophilous oak wood has the highest chances for success in patches with well preserved seed banks and vegetation.

7

Plasticity in dynamics and hygrochastic persistence in Anastatica hierochuntica (Brassicaceae) populations under simulated rainfall treatments

84%

Hegazy A. K. , Kabiel H. F. , Alatar A. A. , Lovett-Doust J.

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tom 61

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nr 3

EN

Anastatica hierochuntica is a monocarpic desert annual whose dry skeletons, enclosing mature fruits, often persist for a number of years. The aerial seed bank in these hygrochastic ‘resurrection plants’ therefore persists too. Life tables and fecundity schedules were constructed for A. hierochuntica populations raised under four water treatments, equivalent to 100, 200, 500 and 1000 mm rainfall. Seedling survivorship showed a Deevey type III curve for 100 mm, and a type II curve for 200 mm, while 500 and 1000 mm treatments produced Deevey type I curves. Fewer seeds germinated and seedling survivorship was lower in the low water treatments. The stage-specific mortality rate reached 0.75 under the 100 mm treatment in the seed germination stage, compared to 0.08 under the 1000 mm treatment. Increased water availability resulted in greater plant growth and reproductive output, in terms of both number of seeds per individual and reproductive value. In field studies, aerial seed banks of small plant sizeclasses (from 1 to 32 cm³) were depleted within 3-to-7 years. For the large size-classes, > 32 cm³, only a portion (79.7-44.4%) of the seeds produced were dispersed during the observational experiment (the rest remaining within the tumbleweed ball, available for subsequent germination). The projected seed bank life-time for populations raised under different water treatments increased more than fivefold (from 3 to 17 years) for the 100 mm compared to the 1000 mm rainfall treatments. Local persistence of populations was thus likely to be reduced by water stress. Populations of A. hierochuntica characterized by weak plant growth and a preponderance of small size-classes will be more vulnerable to extinction due to their low reproductive output and reduced aerial seed bank reserve.

8

Ancient forest species and the diversity of vegetation and seed bank indicate the aptitude of transformed thermophilous oak wood patches for restoration

84%

Kwiatkowska-Falińska A. , Panufnik-Mędrzycka D. , Wódkiewicz M. , Sondej I. , Jaroszewicz B.

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2013

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tom Vol. 61, nr 1

65--78

EN

Thermophilous oak wood is the most species-rich forest habitat in the zone of mixed deciduous forests. A very limited amount of it has been saved in good condition. We investigated the principal hypothesis that the vegetation and seed banks, especially of the ancient forest species, are good indicators of habitat naturalness and its aptitude for restoration. Vegetation and seed bank sampling were carried out in fragments of forest with a known management and disturbance history over the past 80 years. We predicted that natural and anthropogenic transformations of tree stands would be significant factors shaping species composition and similarity of vegetation and seed banks. The closest similarity was observed between the seed banks of plots which were never logged. The least related to others was the seed bank of the logged site, whose soil was ploughed prior to tree replantation. The highest number of ancient forest species was recorded in the vegetation (33 species) and in the soil seed bank (21 species) of the least transformed patch of thermophilous oak forest. It was decreasing gradually with increase of the tree canopy cover on the research plots. Our results indicate also that the higher the coefficient of similarity between seed bank and vegetation, especially of the ancient forest species, the higher the forest’s naturalness. We conclude that restoration of thermophilous oak wood has the highest chances for success in patches with well preserved seed banks and vegetation.

9

Generative reproduction in Rumex confertus Willd. populations

84%

Stosik T.

Electronic Journal of Polish Agricultural Universities. Series Biology

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2007

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tom 10

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nr 4

10

Podobieństwo glebowego banku nasion i aktualnego stanu zachwaszczenia w uprawie pszenicy ozimej

84%

Sekutowski T. , Smagacz J.

Journal of Research and Applications in Agricultural Engineering

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2011

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tom Vol. 56, nr 4

93-98

PL

W badaniach własnych porównywano zasobność glebowego banku nasion z zachwaszczeniem łanu pszenicy ozimej w zależności od systemy uprawy i produkcji. Badania obejmowały ocenę składu gatunkowego i liczebność chwastów w łanie pszenicy ozimej oraz zapasu nasion chwastów w warstwie 0-20 cm. Analizy porównawczej dokonano przy użyciu wskaźników ekologicznych: ogólnej różnorodności Shannona i dominacji Simpsona. We wszystkich systemach produkcji liczba gatunków nasion chwastów w glebie była mniejsza niż liczba gatunków chwastów w łanie pszenicy ozimej. Największą bioróżnorodnością zarówno w glebowym banku nasion, jak i w łanie pszenicy ozimej charakteryzowała się uprawa ekologiczna. Największe podobieństwo glebowego banku nasion z zachwaszczeniem łanu stwierdzono w systemie ekologicznym oraz w monokulturze w uprawie uproszczonej. Najwyższe wskaźniki różnorodności Shannona oraz najniższe wskaźniki dominacji Simpsona zarówno dla gleby, jak i dla łanu stwierdzono dla uprawy ekologicznej. Najwyższe wskaźniki dominacji Simpsona i zarazem najniższe wskaźniki różnorodności Shannona dla gleby oraz łanu stwierdzono dla monokultury (uprawa uproszczona i tradycyjna).

EN

In the experiments the soil seed bank with weeds infestation of winter wheat depending on tillage and crop production systems were compared. The experiments included assessment of weed species composition and the numbers of weeds in winter wheat and the weed seeds stock in the 0-20 cm soil layer. The analysis was conducted using ecological index: Shannon's total diversity and Simpson's domination. In all compared production systems the number of species of weed seeds was lower than in the canopy of winter wheat. The greatest biodiversity in the soil seed bank and in the canopy of winter was observed in organic farming. The greatest similarity between the soil seed bank and wheat infestation was found out organic farming and in monoculture in reduced tillage. The greatest index of Shannon diversity and bottom index of Simpson domination both for the soil and the canopy were found out in organic farming. But the greatest index of Simpson domination and bottom index of Shannon diversity for the soil and the canopy were found out in monoculture (conventional and reduced tillage).

11

Seed banking of Polish endangered plants - the FlorNatur Project

67%

Puchalski J. , Niemczyk M. , Walerowski P. , Podyma W. , Kapler A.

Biodiversity: Research and Conservation

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2014

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tom 34

12

67%

Wodkiewicz M. , Kwiatkowska-Falinska A. J.

Acta Societatis Botanicorum Poloniae

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2010

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tom 79

|

nr 2

157-166

EN

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.

13

Plasticity in dynamics and hygrochastic persistence in Anastatica hierochuntica (Brassicaceae) populations under simulated rainfall treatments

67%

Hegazy A. K. , Kabiel H. F. , Alatar A. A. , Lovett-Doust J.

|

2013

|

tom Vol. 61, nr 3

493--504

EN

Anastatica hierochuntica is a monocarpic desert annual whose dry skeletons, enclosing mature fruits, often persist for a number of years. The aerial seed bank in these hygrochastic ‘resurrection plants’ therefore persists too. Life tables and fecundity schedules were constructed for A. hierochuntica populations raised under four water treatments, equivalent to 100, 200, 500 and 1000 mm rainfall. Seedling survivorship showed a Deevey type III curve for 100 mm, and a type II curve for 200 mm, while 500 and 1000 mm treatments produced Deevey type I curves. Fewer seeds germinated and seedling survivorship was lower in the low water treatments. The stage-specific mortality rate reached 0.75 under the 100 mm treatment in the seed germination stage, compared to 0.08 under the 1000 mm treatment. Increased water availability resulted in greater plant growth and reproductive output, in terms of both number of seeds per individual and reproductive value. In field studies, aerial seed banks of small plant size-classes (from 1 to 32 cm3) were depleted within 3-to-7 years. For the large size-classes, > 32 cm3, only a portion (79.7-44.4%) of the seeds produced were dispersed during the observational experiment (the rest remaining within the tumbleweed ball, available for subsequent germination). The projected seed bank life-time for populations raised under different water treatments increased more than fivefold (from 3 to 17 years) for the 100 mm compared to the 1000 mm rainfall treatments. Local persistence of populations was thus likely to be reduced by water stress. Populations of A. hierochuntica characterized by weak plant growth and a preponderance of small size-classes will be more vulnerable to extinction due to their low reproductive output and reduced aerial seed bank reserve.

14

Effect of two management techniques applied to the reduction of Juncus maritimus (Lam.) abundance in a selected temporary wetland

67%

Sahib N.

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tom no. 41

120--132

EN

Moderate management of temporary wetlands is one of the most proper methods for their restoration and conservation. The cessation of use may lead to high biomass domination by macrophytes as Juncus maritimus (Lam.) that changes plant community structure, threatens species biodiversity, and becomes a danger for their conservation. The experiment was carried out in Sidi Boughaba coastal reserve in Morocco. Two management techniques of wetlands were tested, cutting and uprooting of the rush. Four experimental plots (4.2 × 2.9 m) within the rush belt were set up, with intact plots as a control. Vegetation structure and water levels were monitored on 96 quadrats over two years. The six visits dates, three visits per year (February, April, June), were monitored over two years. The abundance and richness of species were studied, simultaneously with the density of the seed stock in each plot. Results showed that both techniques allowed the opening of the habitat with a significant increase of richness and abundance of species, particularly the restoration of characteristic species of the temporary wetland from the seed bank. The cut technique seems to have less of an effect on the seed stock, total seeds median value was 6.5 in cut plots versus 5 in uprooting plots, being regularly applied given the rapid encroachment of the rush.

PL

Umiarkowane zarządzanie okresowymi środowiskami podmokłymi jest jedną z najbardziej właściwych metod ich odtwarzania i ochrony. Zaniechanie użytkowania może prowadzić do znaczącej dominacji biomasy makrofitów, takich jak Juncus maritimus, która zmienia strukturę zespołu roślinnego, ogranicza różnorodność gatunkową i stanowi zagrożenie dla ochrony siedlisk. Eksperyment prowadzono w przybrzeżnym rezerwacie Sidi Boughaba w Maroku. Testowano dwie techniki gospodarowania – cięcie i wykorzenianie sitowia. Założono cztery poletka doświadczalne (4.2 × 2.9 m) w pasie sitowia, stosując poletka bez jakichkolwiek zabiegów jako kontrolę. Strukturę roślinności i poziom wody monitorowano sześciokrotnie na 96 kwadratach w ciągu dwóch lat, trzykrotnie w ciągu roku (w lutym, kwietniu i czerwcu). Badano obfiobfitość i bogactwo gatunkowe oraz zagęszczenie banku nasion w każdym poletku. Wyniki dowodzą, że obie techniki umożliwiają otwarcie siedlisk ze znaczącym wzrostem bogactwa i obfitości gatunków, szczególnie przywracanie z banku nasion gatunków charakterystycznych dla siedlisk podmokłych. Technika wycinania skutkuje, jak się wydaje, słabszym wpływem na bank nasion, stosowana regularnie ułatwia gwałtowny rozrost sitowia.

15

The potential role of nests of Black-billed Magpie Pica pica L. in accumulation and dispersal of seeds in agricultural landscape

67%

Czarnecka J. , Kitowski I.

Polish Journal of Ecology

|

2008

|

tom Vol. 56, nr 4

673-682

EN

The study aimed to describe the seed pool accumulated in the nest material of Magpie Pica pica, and to determine the importance of this mechanism of seed dispersal for such ecological processes as colonization of new habitats and expansion of alien plants. The seedling germination and seed extraction methods were used to determine seed abundance in the soil layer, the inner layer, and in the lining of 9 nests collected in three types of agricultural landscape: the first with domination of arable fields; the second with similar shares of arable fields and other landscape elements such as meadows of different types, shrubs, tree clumps and rushes; and the third with domination of lowland hay meadows. In all the nests, considerable numbers of diaspores were found (from 26 to 371 seeds per nest, belonging to more than 80 taxa). The main plant groups found in the nests are species connected with field roads, weeds and ruderal species, but also meadow and brushwood species were found there. The soil was gathered by birds from habitats with low vegetation cover and large areas of bare soil. Although the structure of seed pool of nests suggests that soil was mainly collected in the close vicinity of the nests. future location, this mechanism of seed dispersal can probably be involved in long distance dispersal. Seeds of two rare kenophytes: Erucastrum gallicum (Willd.) O. E. Schulz and Diplotaxis tenuifolia (L.) DC were found in the material of nests localized more than 100 m away from their closest populations. It can be assumed that this mechanism of seed dispersal can play a potential role in the expansion of alien plants and colonisation of new habitats.

16

The effects of different types of woodstand disturbance on the persistence of soil seed banks

67%

Kwiatkowska-Falinska A. , Panufnik-Medrzycka D. , Wodkiewicz M. , Sondej I. , Jaroszewicz B.

|

nr 2

EN

The research was conducted on four patches of thermophilous oak wood in Białowieża Primeval Forest: A – with a woodstand: oak + approx. 30-year-old hornbeam + hornbeam brushwood; B – with a hornbeam stand formed by natural seed fall after logging (ca. 1920) oaks; C – after logging oaks and replanted (ca. 1965) with pine and oak; D – with a natural low-density oak stand. Species composition and seed bank density were estimated using the seedling emergence method. Seedling emergence was observed over two vegetation seasons. Research demonstrated that: 1) the species abundance of the seed banks depends on canopy cover (A, B approx. 50 species; C, D approx. 70 species); 2) the floristical similarity (Sørensen’s index) of the seed bank and ground vegetation is higher in the undisturbed patch D (0.50) than in disturbed patches (0.30-0.35); 3) species diversity in plots A, B, C, D (H’=12.5; 13.4; 15.5; 16.9) and seed bank density per m2 (432.5; 958.0; 1486.5; 2268.0) are negatively correlated with the degree of patch shading; 4) the average weight of diaspores in the seed banks of shady plots is lower (A, B approx. 0.003 g) than that of sunny plots (C, D approx. 0.08 g); 5) the share of long-lived diaspores increases in patches after logging.

17

Gene pool conservation programme of Norway spruce Picea abies (L.) Karst. in the Beskid Mts

67%

Jurasek M.

Dendrobiology

|

2004

|

tom 51 Supplement

EN

The paper describes the measures adopted by the Czech State Forests for the conservation and reproduction of the Norway spruce gene pool in the Moravian-Silesian Beskid Mts. In addition to the assurance of natural regeneration in genetically valuable stands and the use of high-quality autochthonous stands as seed sources for artificial regeneration, the measures include selection of plus-trees, establishment of seed orchards, seed stands and clone archives, and identification of gene pools. Seeds of the most valuable regional populations are deposited in a seed bank.

18

Soil seed banks in lakeshore wetlands: relation to the extant vegetation

67%

Peng Y.-L. , Wu N. , Gao X.-F. , Fang Z.-Q. , Xiao W.-Y.

Polish Journal of Ecology

|

2010

|

tom 58

|

nr 3

EN

Seed bank composition and germination characteristics are necessary for modeling wetland vegetation composition. Yet there are few studies about the seed bank difference between plant communities in lakeshore wetlands. Seed banks are also known to play important roles in the vegetation restoration process. Environmental factors such as water level, temperature, or nutrient levels can affect vegetation composition and seed bank composition. The relationships between environmental factors and seed banks of wetlands in the field are still unknown. The Jiuzhaigou Nature Reserve is located at the eastern edge of Qinghai-Xizang Plateau. The lakeshore wetland vegetation is dominated by Phragmites australis (Cav.)Trin. ex Steud., Typha latifolia L., Carex pamirensis C. B. Clarke, Equisetum fluviatile L. The wetlands in Jiuzhaigou (118 lakes) are under strong pressure such as trampling and enhanced construction for travel. Plant restoration is necessary for protection of these areas. We investigated the soil seed bank in six lakeshore wetlands in this area using the seedling emergence method. Sediment samples (0–2 cm, 2–5 cm, 5–10 cm intervals from surface to bottom) were taken with core (diameter 5 cm) in April and from each replicate samples were spread on two plastic trays. Trays were randomly arranged in the greenhouse and watered daily. Seedlings were counted weekly after emergence, and removed as soon as they could be identified. Our study showed that seed density in all soil layers samples was negatively correlated to water depth. Water depth can explain 45% variance of species richness in surface layer in sediment. Species richness in extant vegetation can explain 45, 48, 25% variance of species richness in total 10 cm and in 2–5 cm and 5–10 cm layer sediment respectively. Dominant species cover in extant vegetation, site altitude, total nitrogen, total phosphorus and total organic carbon in soil showed no correlation with species richness in seed bank. Mean seed densities in wetlands ranged from 0 to 15945 m⁻². A total of 23 species germinated in seed bank, while 85 species were found in extant vegetation. The dominant species in seed bank and extant vegetation showed great difference. The total number of species and seedlings that germinated in different layers was not significantly different. But the second layer had the greatest seed density. The relationship between seed bank and extant vegetation differed from one species to another. We should use different restoration strategies for different plant communities.

19

Small scale spatial pattern of a soil seed bank in old-growth decidous forest

67%

Wodkiewicz M. , Kwiatkowska-Falinska A.

Polish Journal of Ecology

|

2010

|

tom 58

|

nr 3

EN

We studied an old growth deciduous forest seed bank to examine how its potential role in regeneration is shaped by natural forest environment. Our research questions were: is the spatial pattern of seed bank influenced by local variation in elevation, soil moisture and light intensity, and what is the impact of herb layer characteristics on seed bank pattern. We recorded species composition of the herb layer and seed bank on a 2 × 40 m study plot divided into 20 quadrates, situated in a natural oak-hornbeam forest, in the Białowieża Primeval Forest, (NE Poland). Soil cores were sampled from two soil layers (0–5 cm and 5–10 cm) yielding altogether 40 samples of a total 15.9 dm3 and 0.159 m². Seeds were extracted from soil samples under a microscope. Ellenberg indicator values were used to characterize light (L) and moisture (F) conditions. Relative quadrate elevation was averaged for nine points. There were 6.65 × 10³ seeds m⁻² in upper soil layer and 3.00 × 10³ seeds m⁻² in lower soil layer. Seed bank structure constituted of patches 6 m diameter in the upper soil layer and 4 m in the lower soil layer. Aggregated pattern of the seed bank was influenced by clumped distribution of plants in the herb layer. Seed bank species richness in the upper soil layer was correlated with moisture (r = 0.485, P =0.03) and light (r = 0.526, P = 0.0172) values. Seed densities were correlated with moisture (r = 0.848 P <0.0001 upper and r = 0.491 P = 0.0278 lower soil layer) and light (r = 0.803 P <0.0001 upper and r = 0.751 P = 0.0001 lower soil layer). Seed density in upper soil layer was negatively correlated with elevation (r =–0.485 P = 0.0422). Higher seed density and species richness of the seed bank associated with better light conditions and higher moisture is probably caused by higher seed production in favourable conditions, and factors promoting seed persistence in soil. Our results indicate, that even subtle changes in light, moisture and mean relative elevation can shape seed bank spatial pattern on a fine local scale, differentiating the response of this community to small scale disturbances present in natural forests.

20

Reproductive potential of the alien species Asclepias syriaca [Asclepiadaceae] in the rural landscape

67%

Csontos P. , Bozsing E. , Cseresnyes I. , Penksza K.

|

nr 2

383-388

EN

In the beginning of its introduction Common milkweed, Asclepias syriaca L. was used in Hungary as ornamental plant. After escaping from cultivation it has become wide spread during last decades of the 20th century. Nowadays, it covers large areas especially on sandy soils, and its further appearance is expected on dry, deforested and degraded areas. Two neglected fields and one abandoned vineyard were selected. For sampling two quadrates of size 4 m² were used at each stand. The stands were characterized by the following variables: density of stems, percentage of reproductive stems, average number of inflorescences, average number of fruits, fruits per all inflorescences on a stem, pods per fruited inflorescences on a stem, average number of seeds per fruit. In the same quadrates the soil seed bank was studied at two depths (0–5 cm and 5–10 cm). The results showed that the density of stand, percentage of reproductive specimens and average number of fruits were significantly higher on the neglected fields than on the abandoned vineyard. In the neglected fields large number of seeds were detected in the upper soil-layer (2.7– 18.6 × 10³ seeds m⁻²), but in the lower soil-layer much fewer seeds were found and only in one of the fields. Common milkweed seeds were almost completely missing from both soil layers of the abandoned vineyard. However, the seeds recovered from the soils practically did not germinated, indicating that seeds of earlier years sets have lost viability, i.e. the studied stands of A. syriaca did not form a persistent soil seed bank. Nevertheless, the fresh seed production of the neglected field populations, that can reach 7–10 thousands seeds m⁻², may cause a very strong propagulum load not only in the site but also on the surrounding areas.