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Comparison of Seed Longevity for Thirty Forest, Grassland and Weed Species of the Central European Flora : Results of a Seed Burial Experiment

Csontos P., Kalapos T., Tamás J.

Polish Journal of Ecology

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2016

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Vol. 64, nr 3

313--326

EN

We compared seed longevity of herbaceous species in three habitat types differing in stability. We hypothesized that seed longevity is the lowest for forest species (living in stable habitat), the highest for weeds, while species of xerothermic grasslands take an intermediate value. Ten species were selected from each of the three habitats with balanced representation of plant families among habitats. Seeds of the 30 species were deep buried at 65 cm depth, then replicates recovered after 1, 2, 3, 4 and 6 years, and germinated in an unheated greenhouse. Weeds expressed the highest germination rate (36.1% in average) exceeding forest (14.4%) and grassland species (10.2%) which did not differ significantly. The number of species with transient, short-term persistent and long-term persistent seed bank, respectively, was 1, 7 and 2 for grasslands; 1, 3 and 6 for forests; and 0, 1 and 9 for weeds. As expected, weeds possessed the highest seed longevity. Contrary to our assumption, low seed longevity was not the norm among forest understorey species, and seed longevity of xerothermic grassland species was not intermediate but the shortest one. Ecological background of differences between hypotheses and experimental results are discussed. First record on seed bank type is reported here for 12 species: Dianthus pontederae, Digitalis grandiflora, Ferula sadleriana, Hieracium sylvaticum, Inula ensifolia, Jurinea mollis, Lychnis coronaria, Saponaria officinalis, Scorzonera austriaca, Secale sylvestre, Stipa borysthenica, Verbascum lychnitis.

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New Stand of Invasive Neophyte Ambrosia artemisiifolia L. and Its Potential Reproduction

Csontos P., Angyal Z., Chmura D., Nagy J., Halbritter A., Tamás J.

Polish Journal of Ecology

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2015

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Vol. 63, nr 3

453--459

EN

A new stand, formed by some fifty individuals of Ambrosia artemisiifolia L., an invasive plant of alien origin, was discovered at the Katowice railway station (southern Poland), in 2011. Two years later, the stand (increased to more than 160 individuals in the meantime) was re-visited, phytosociological survey was made, and four soil cores (5 cm deep and 80 cm2 surface area, each) were taken for seed bank studies. The phytosociological sampling revealed 28 co-occurring vascular species, most of them representing hemicryptophyte and geophyte life forms. According to Ellenberg's values, the species pool indicated sunny (L7 and L8 species dominating) and semi-dry (mainly F4 species) habitat for the common ragweed population, whereas Zarzycki's soil granulometric data reflected coarse-grained soil. Albedo of the soil was lower than that of the vegetation thus sparsely vegetated sites were considered as heat accumulating microhabitats that might support establishment of the thermophilic A. artemisiifolia. During soil seed bank analysis a high number of naturally opened fruits (dehiscent achenes) were found (718.75 per m2) most probably indicating frequent germination in previous years. Greenhouse germination tests proved successful germination of 125 individuals per m2, which was considered enough to maintain the A. artemisiifolia stand at the station. The results call attention to a newly discovered, established population with increasing demography of A. artemisiifolia, a highly allergenic introduced weed of Poland.

3

Seed mass variation in central European populations of invasive Impatiens glandulifera Royle

Chmura D., Csontos P., Sendek A.

Polish Journal of Ecology

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2013

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Vol. 61, nr 4

805--809

EN

Positive correlation between seed weight and germination capacity is common for the vast majority of species. It is also known that seed weight can vary along a latitudinal gradient. The seed mass of the invasive Himalayan balsam (Impatiens glandulifera), which is native to East Asia, was examined in relation to distinct geographical regions in Poland (Bielsko-Biala: N49°52′32″, E18°57′43″; Katowice: N50°12′8.3″, E18°57′26″; Tworków: N50°01′22″, E18°15′28”); Hungary (Rum: N47°06′41″, E16°50′45″; Rábahídvég: N47°03′54″, E16°44′59″) and Germany (Halle: N51°28′47″, E11°57′12″; Marburg: N50°48′32″, E8°46′31″). The study revealed that seed mass varied both among the countries and among specific populations within Poland and Germany. In Hungary, the 50 seed lots were the lightest 0.29 g and 0.31 g in respective localities and the heaviest in single populations in Poland – 0.61 g and in Germany – 0.57 g. In the present study, populations located more southwards had the lightest seeds in contrast to the commonly encountered pattern. Higher temperature, lower precipitation and as a consequence, a shortage of water can be crucial factors that affect the seed mass of I. glandulifera. Taking into account the lower frequency and abundance of the species in Hungary, the lower seed mass may probably contribute to the limited distribution range in this region.

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Reproductive potential of the alien species Asclepias syriaca (Asclepiadaceae) in the rural landscape

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

Polish Journal of Ecology

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2009

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Vol. 57, 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 m[^2] 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 x 10[^3] 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.