Explore the vast range of titles available.

1 We evaluated the responses of native grassland sods to a variety of types of disturbance in order to assess hypotheses about the competitive effects of established vegetation on seed germination and seedling establishment. In particular, we consider whether germination is more responsive to the magnitude and duration of vegetation removal (competitive release) or to individual disturbance types (specific effects). 2 Field-collected sods of coastal tallgrass prairie were subjected to no manipulation, cutting with clippings left, cutting with clippings removed (hayed), burning, and complete destruction of established vegetation under greenhouse conditions. The emergence and fate of seedlings, as well as light penetration through the canopy, were followed for a period of 4.5 months. 3 Total seedling emergence increased from cut to control, hayed, burned and plants-removed treatments. Several periods of increased seedling emergence suggested responses to both light penetration and seasonal change. 4 Species richness was lowest in cut sods and highest in sods that had plants removed or were burned. Rarefaction analysis showed that these differences were largely those expected from differences in seedling number, except for the cut treatment, which produced fewer species per seedling than other treatments. 5 Indicator species analysis and ordination methods revealed that seedling community composition overlapped strongly across all treatments, although the area of ordination space did increase with increasing numbers of seedlings. 6 Overall, most of the effects of disturbance could be explained by cumulative light penetration to the soil surface, an indicator of total competitive release, although a few specific effects could be found (particularly for the cutting treatment). Thus, these results generally support the competitive release hypothesis.

The abundance and variety of seedlings in Baltic coastal grasslands was studied in cattle grazed and ungrazed areas in seashore and delta on the western coast of Finland. The vegetation, seed bank and environmental conditions of the same sites were also studied. Altogether 4609 seedlings were observed in 79 field plots (20 cm x 20 cm) making an average of 1458.54 seedlings/m2. The majority of the seedlings were dicots (67.5%) and perennials (96.8%). Altogether 44 species and an average of 4.14 species per plot were identified as seedlings. The most abundant taxon, Carex formed 23.2% of all the seedlings observed in the field. In the delta the seedling density was two times that found at the seashore. Also, the numbers of species of seedlings per plot were significantly higher in the delta than in the seashore, but in total, more species germinated from the seashore than from the delta even though the number of plots was higher in the delta (n = 51) than in the seashore (n = 28). The numbers of species and seedlings per plot were smaller in grazed sites than in ungrazed ones similar to the pattern earlier reported concerning the mature vegetation and seed bank. The mean numbers of seedlings were the highest at lower geolittoral plots (about 20 cm elevation), where the seed bank was also densest. About 60.0% of the mature species in the plots were also detected as seedlings and 91.4% of the seedling species were found in the mature vegetation of the plots. The number of seedlings was positively correlated with the cover of mature vegetation giving support to the nurse effect theory. Seedling numbers were negatively correlated with the abundance of litter indicating that litter restricts germination because it is a mechanical barrier but also decreases the amount of light. The number of seedlings and species, both in total and per unit area, were greater in the seed bank than in the field seedling population. The seedling population was more similar to the mature vegetation than to the seed bank.

Coastal marshes are key habitats contributing to organic carbon (OC) storage but remain understudied in Nordic regions regarding Blue Carbon processes. This study quantified OC stocks in above- and below-ground plant biomass and in the top 50 cm-soil across 12 grazed and ungrazed marshes, spanning a major environmental gradient, and assessed how biotic (plant communities, livestock grazing) and abiotic (soil properties, environmental conditions) drivers shape OC storage. Soil OC stocks accounted for ∼ 73 % of total OC in grazed sites and ∼ 63 % in ungrazed ones and was higher in grazed sites (99.7 ± 57.9 Mg ha−1) than in ungrazed sites (78.2 ± 44.2 Mg ha−1). Grazing and the large-scale environmental gradient strongly structured plant communities, partly by regulating reed (Phragmites australis), prevalent in ungrazed sites. Abiotic soil properties were major large-scale drivers of soil OC storage, while grazing affected soil OC storage indirectly through plant composition. Soil OC increased with finer textures, whereas vegetation and grazing effects were variable and locally expressed. Aboveground OC stocks were reduced by grazing, both directly through biomass removal and indirectly by reducing reed dominance. Belowground OC stocks were driven by plant community composition and indirectly by grazing effects on vegetation. Root biomass was concentrated in the top 15 cm in grazed sites and deeper (15–50 cm) in ungrazed sites, reflecting contrasting plant strategies. Overall, soil OC stocks in Nordic coastal marshes fall within the lower range of global estimates. These findings highlight the need to consider soil processes, grazing and environmental gradients in the sustainable management of Nordic coastal marshes and their carbon storage potential.

The objective of this study was to investigate the effects of flooding and draw‐down on the germination from the coastal grassland seed banks and to determine whether the effect of flooding varies between the delta and the seashore. Seed bank samples were collected from three shore transects in SW Finland, two on the shore of the Baltic Sea and one on the delta of River Kokemäenjoki. Samples were germinated in non‐flooded and flooded conditions for over a month, after which both treatments were maintained in non‐flooded conditions. A total of 9267 seedlings of 47 species germinated and mean density of seeds in the soil was ca. 84 000/m². Most of the seedlings were monocots (98%) and perennials (98%). Ca. 30–40% of the species found in the above‐ground vegetation had a seed bank including the majority of the most abundant species. The number of seeds and species richness increased as the organic layer became thicker. The organic layer was thicker in the seashore samples and the seed bank was significantly larger than in the delta. The flooding and draw‐down treatment significantly increased the number of germinating seedlings in the seashore and also increased species richness in two transects, one in the delta and the other in the seashore. Two species, Schoenoplectus tabernaemontani and Typha latifolia, had significantly higher germination in the flooded treatment than in the non‐flooded. Apparently, many species in these coastal grasslands have adapted to flood disturbance and for seeds of some species flooding may work as a positive signal, possibly breaking dormancy.

The objective of this study was to evaluate the effects of grazing on shoreline meadows. To accomplish this, five ungrazed and four grazed meadow transects (a total of 411 1 m⁲ plots) were studied on the west coast of Finland (61°30′-61°33′ N/21°28′-21°41′ E). The summed cover of all species was decreased by grazing. The abundances of annuals+biennials, perennials, dicots and pteridophytes were decreased while the cover of monocots was increased by grazing. This trend was similar in all elevation classes and mainly both in the seashore and the delta. In the seashore grazing decreased the cover of chamaephytes and therophytes and in delta it seemed to increase the cover of geophytes and hemicryptophytes, but these results were influenced by differences in elevation. The height of vegetation and the dry biomass were smaller in the grazed than in the ungrazed plots. Agrostis stolonifera, Carex nigra, Festuca rubra, Juncus gerardii, Leontodon autumnalis, Poa subcaerulea and Potentilla anserina were more abundant in grazed, while the abundances of Filipendula ulmaria, Galium palustre, Lathyrus palustris and Phragmites australis were greater in ungrazed plots. Shores are multi-stress environments in which the water level fluctuation narrows the species pool. Grazing cattle is a disturbance, which has varied effects on different vegetation zones and on different kinds of species. Overall, it appears that stress-tolerant perennial monocots and halophytes are favored by grazing in those shoreline communities.

Previous studies have indicated that the relationship between community biomass and species density can be represented by a multivariate model in which abiotic variables influence species density both through effects on biomass and through effects on the species pool. In this paper, we use data from grazed and ungrazed coastal meadows in Finland to evaluate and extend this general conceptual model of the factors controlling species density. Structural equation analysis was used to evaluate a model for all meadows and then to perform a multigroup analysis to determine how grazed and ungrazed meadows differ. By itself, biomass could explain only 12% of the variation in species density while the multivariate model was able to explain 47% using five types of predictor variables: site, soil, flooding, grazing, and biomass. Analyses found that flooding explained the greatest amount of variability in species density, primarily through negative effects on the species pool. Grazing was also found to have a strong effect on species density and results suggest that its negative influence may be largely through reductions in the species pool in grazed meadows. The most important difference found between grazed and ungrazed meadows was that species density had a strong negative relationship to biomass in the ungrazed meadows but no significant relationship in the grazed ones. Thus, it appears that the influence of competition on species density was much greater in ungrazed meadows compared to grazed ones.

The vegetation of four grazed and five ungrazed shore grasslands was studied in seashore and in delta on the southwestern coast of Finland. Ordinations and classifications separated delta plots from seashore plots, which were further divided into reed stand plots, epilittoral plots and geo- and hydrolittoral plots. The partitions reflected flooding stress, moisture conditions, grazing and properties of parent material. Elevation explained the data best. The primary factor in producing the vegetation zonation pattern in these Baltic coastal grasslands is the short-term fluctuation in sea-level. Although grazing was not the most important factor for explaining the variability in the data, its impact on the vegetation was considerable. Phragmites australis was much more common in ungrazed than in grazed plots. It dominated the hydrolittoral, was abundant in geolittoral and existed even in transition zone of the ungrazed transects. In grazed transects Agrostis stolonifera and Eleocharis uniglumis dominated the hydrolittoral. The lower geolittoral was dominated by perennial graminoids. In the middle and upper geolittoral, forbs were more frequent and abundant. In the grazed seashore transects, the lower geolittoral was dominated by Juncus gerardii, while in the ungrazed transects Calamagrostis stricta, Agrostis stolonifera and Juncus gerardii formed the zone together with Phragmites australis. The transition zone in the grazed transects was a narrow drift wall, in the ungrazed transects, however, it was much broader and dominated by tall growing plants. On fine-grained substrate, the epilittoral was dominated by Agrostis capillaris, Carex nigra and Deschampsia cespitosa and on till by Deschampsia flexuosa and Galium verum.

The seed banks of three grazed and three ungrazed seashore meadows were studied on the west coast of Finland. 8486 seedlings (mean 13 669 seedlings/m2) germinated from cold-treated samples (n = 343; depth = 10 cm). Most seedlings and species were monocots and perennials. The seed bank flora included 54 dicots vs. 28 monocots and 66 perennials vs. 16 annuals. The most abundant species were Juncus gerardii, Schoenoplectus tabernaemontani, Eleocharis uniglumis, Agrostis stolonifera, Juncus bufonius and Carex nigra, which made up 73 % of the seed bank. Numbers of species and seedlings differed between elevation classes. Species richness was highest in elevation class 50 - 70 cm. The highest seed density occurred in class 20 - 50 cm. A model for size and species composition of the seed bank in relation to elevation is presented. The seed bank was larger and richer in species in the ungrazed than in the grazed sites, but not so in the upper elevations and closest to the open sea. Grazing reduced the size of the seed bank of Agrostis stolonifera, A. capillaris, Calamagrostis stricta, Elymus repens, Juncus bufonius, Limosella aquatica and Schoenoplectus tabernaemontani, but increased that of J. gerardii. 32 species germinated only from ungrazed samples and 11 species only from grazed ones. Multivariate classification resulted in nine sample groups. The ordination scatter was best explained by the flooding stress variables, elevation, the distance from the water line and the number of helophyte species in samples. 75 species were found both in the seed bank and in the vegetation, but there was a significant lack of resemblance (in the Mantel test) due to over-representation of some species. Eight species occurring only in the seed bank were mainly annuals or biennials (63 %); those occurring only in the established vegetation (86 species) were mainly perennials (86 %).

The seed banks of two delta meadows were studied on the west coast of Finland (61°33′N, 21°39′—21°41′E) to evaluate the possibilities of using seed bank in the restoration of coastal wetland meadows. The objective of the study was to determine the size, composition and species richness of germinable seed bank, estimate the effect of flooding on the seed bank, and describe the similarities and differences between seed bank and the aboveground vegetation. The study areas are conservationally important. A total of 125 samples were taken with a corer of 4.8 cm in diameter to the depth of 10 cm. Altogether 4977 seedlings were observed, yielding an average of 22 005 ± 1880 seedlings/m2. Most seedlings and species in the seed bank were monocotyledons, perennials and hemicryptophytes, similar to the aboveground vegetation. Although 36 species were found in both the seed bank and vegetation, there was a significant lack of similarity overall (Mantel test). The seed bank flora included 24 dicot vs. 25 monocot species and 41 perennial vs. 8 annual species. Many of the species found only in the seed bank were annuals or biennials (13 species, 46% of total) and those growing only in the aboveground vegetation were mainly perennials (52 species, 92% of total). The most abundant species found in the seed bank were Carex nigra, C. aquatilis, Juncus gerardii, Calla palustris, and Potentilla palustris, which together made up 74% of the seed bank. The numbers of species differed significantly between different elevation classes and were highest at middle elevations. Seed bank is an important part of these delta grassland communities and can be utilised in restoration.

The richness of vascular plant species in four grazed and five ungrazed shore meadow communities was studied on the west coast of Finland, near the town of Pori (61°30′— 61°33′N, 21°28′—21°41′E). In the transects established, plant species were studied in 412 1-m2 plots and in the adjacent areas. The flora included a total of 183 vascular plant species representing 108 genera. The shore plant communities were dominated by perennial monocot species, although the number of dicot species was higher. The vascular plant species richness (11.5±4.7) in 1-m2 sample plots was significantly higher at the seashore than in the delta of the river Kokemäenjoki. A model is constructed of the factors that affect species richness in seashore meadows. Species richness increased significantly with increasing distance from the waterline, and more importantly (R2 = 0.26) with elevation above the mean sea level. The linear increase in species richness continues up to a certain elevation, the latter being dependent on the amplitude of water level fluctuation. Species richness decreased significantly with an increase in biomass or height of vegetation. These variables are negatively correlated with elevation and have only secondary importance for species richness. In the delta area no significant results were obtained for species richness in general. The vascular plant species richness was higher in grazed plots than in ungrazed ones in the delta, but in the transects most exposed by the sea the opposite was true. The influence of grazing on the species richness seemed to be scale-dependent.