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The Influence of Vegetation Structure on the Composition of the Seed Rain and Seedling Pool in Abandoned Molinion caeruleae Meadows

Kostrakiewicz-Gierałt K.

Polish Journal of Ecology

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2017

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Vol. 65, nr 2

269--284

EN

The investigations of the effect of different habitat conditions on the composition of the seed rain and seedling pool were conducted in the years 2014 and 2015 in abandoned patches of Molinion caeruleae dominated by small-stature meadow taxa (patch I), tall-growing grasses (patch II), as well as shrubs and trees (patch III). Observations showed that along the successional gradient the seed rain and seedling pool diminishes. The prevalence of perennials and native taxa in the seed rain and seedling pool occurred in all the study sites. Moreover, in the propagule and seedling pools of all the patches hemicryptophytes and meadow taxa prevailed but their number decreased in successional sites. Also, the abundance of ruderal and grassland taxa decreased gradually, at expense of number of forest species. Zoochorous species prevailed in the seed rain and seedling pool of all patches. Number of hydrohorous species decreased in successional patches, while the abundance of species with other dispersal modes were similar. Irrespective of patch character, the species producing propagules with medium size dominated in the seed rain and seedling pools, whereas a significant decrease of number of small-seeded species was noticed only in the seedling pool. Despite the diminishing of the seed rain and seedling pool along the successional gradient, the gap creation might be a very effective way of active protection of Molinion caeruleae meadows. However, the gap colonisation requires permanent monitoring to avoid further spreading of undesired taxa.

2

Wintering Farmland Bird Assemblages in West Hungary

Báldi A., Somay L., Kovács-Hostyánszki A.

Polish Journal of Ecology

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2015

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Vol. 63, nr 4

608--615

EN

Farmland bird populations declining rapidly all over Europe. Most of the knowledge is, however, from the breeding season, and much less is known about the winter period, especially from Central and Eastern Europe. We censused wintering farmland bird assemblages in West Hungary, in 2011/2012. The censuses covered semi-natural and seeded grasslands, plough fields and wheat fields. The available winter seed food was estimated for each field from the top soil and from the vegetation. We recorded 25 species with 844 individuals on the fields. Semi-natural grasslands were the most important habitats for species richness of all, granivorous, and resident species, with seeded grasslands as the second best habitat. Abundance showed similar pattern, although with no significant effect for granivorous species and for short-range migrants. Seed mass was significantly different among the habitat types, higher on seeded grasslands and seminatural grasslands than on ploughed sites and winter wheat fields. Date had a significant effect on species richness and abundance with highest values in December. There was a positive significant correlation between bird species richness and seed mass only in December. Our results strengthen former findings that changes and drivers of wintering farmland bird populations may differ between Central and West Europe, and highlight the need for further, large scale studies to provide evidence base to guide agrienvironmental programs.

3

The effect of gaps size on colonization process in Molinietum caeruleae meadows with different habitat conditions

Kostrakiewicz K.

Polish Journal of Ecology

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2011

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Vol. 59, nr 4

677-686

EN

The disturbances defined as an external factor causing biomass removal are a key component of all ecosystems. In phytocenoses with a continuous vegetation cover and a large proportion of perennial plants the fine-scale disturbances create gaps, which are the temporary competitor-free microsites suitable for plant recruitment. The investigations of natural colonization of different size gaps in Molinietum caeruleae meadows were carried out in patches dominated by small species creating delicate, erect or procumbent stems (MC), prevailed by large-tussock grasses (GR), and overgrown by willows (SA). Each patch was represented by ten plots, divided into four square subplots of 0.16 m2, 0.09 m2, 0.04 m2 and 0.01 m2. In each of them the aboveground parts of plants were clipped and removed with the litter. the seedlings recruitment was observed in 2007.2009. The highest species richness in gaps was observed in the MC patch and might be caused by week competition for light from neighbouring plants with delicate, procumbent stems and narrow leaves. The smaller rate of recruitment in SA and GR patches could be caused by overshading willows as well as by the competition from large and dense tussocks of Deschampsia caespitosa and Molinia caerulea. At all patches species richness declined with the decreasing gap size. The developed seedling pool represented both species occurring in the surrounding canopy and such which were not found there. However, their contribution varied between particular patches. Regardless gap size, the MC seedling pool was dominated by species which did not occur in the established vegetation, whereas in GR gaps both groups were represented by similar numbers of taxa and the SA gaps become dominated by species present in the surrounding canopy. Irrespective of patch character, in each subplot the medium-seeded species were represented most abundantly. The recruitment of genets of large-seeded species decreased, while the abundance of individuals ofsmall-seeded taxa increased with the increasing gap size. In the light of the performed study, one might suggest that extent-controlled disturbances can be used as an effective way of the conservation of Molinietum caeruleae patches dominated by small meadow species being outcompeted by large-tussock grasses and over-shaded by willows.

4

Seed mass increase along altitude within four Saussurea (Asteraceae) species in Tibetian Plateau

Wu G., Tian F., Ren G., Liu Z.

Polish Journal of Ecology

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2011

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Vol. 59, nr 3

617-622

EN

Seed mass is a critical life-history character in seed evolutionary ecology. Plant species can present responses in seed mass to environment stresses. We tested the hypotheses that seed mass was positively correlated with altitude within species. We selected four congeneric Saussurea species as study objects, and collected their seeds along altitudinal gradients (2100.4200 m a.s.l.) in the alpine area of the Qinghai-Tibetan Plateau, China. Results showed that mean seed mass of the four species were significantly affected by altitude (P <0.001). There was a general trend of an increase in seed weight with altitude among the populations of the four species. In addition, mean seed mass of four species were not significantly different, but all presented a bigger coefficients of variation within species along altitude gradients. Our results indicate selection pressure within species, with larger seeds occurring at higher altitudes.

5

Effects of seed mass and light on seedling success in Artemisia sieversiana Willd in the Tibetan Plateau

Wu G., Li W., Du G.

Polish Journal of Ecology

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2010

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Vol. 58, nr 3

469-474

EN

Seed mass and light availability are important factors which affect seedling recruitment in plant populations. Effects of seed mass and light availability on seed germination and seedling recruitment in Artemisia sieversiana Willd, which is a widely distributed herbs and a common component species in alpine meadows of the Tibetan Plateau, were tested in a manipulative field experiment. Our research indicated that seed mass and light significantly affected seed germination and seedling emergence and survival and there was a significant interaction effect between seed mass and light availability on these life traits within species. Our study showed that larger seeds presented significant advantages in germination, seedling emergence and survival than smaller seeds under different light availability, especially under deep shade. Our results suggested that seedling success of Artemisia sieversiana appears to be regulated by an interactive effect of seed mass and light availability in alpine meadow of the Qinghai-Tibetan Plateau. In addition, seedlings from larger seeds have more and more stronger advantages from germination, emergence to survival stage than seedlings from smaller seed within species.