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Specific variability and ecological meaning of seed weights
295-330Views:125There is an almost twelve order of magnitude difference in the seed weight of recent plant species. Studying the causes, patterns and consequences of this high variability is a crucial issue in plant ecology. In this paper we summarise the main conclusions of the studies in this topic to get a broad and general view of the possible explanations of high variability in seed weights and its consequences on dispersal, seed predation, seed bank formation, germination, establishment and plant growth, and on the structure and function of plant communities. Because of the extremely high number of papers published in this topic, we aimed at to concentrate on papers published in highranked international journals in the last few decades, having a special focus on publications from the Carpathian Basin. It was found that growth form, body size, genom size, latitude and light availability are responsible for the detected high variability in the seed weights of species. Infra-individual variability is mostly caused by the effects of the position on the maternal plant and the seed size – seed number trade-off. The effect of dispersal by wind or by seed predators on the variability of seed weights and its ecological consequences are the most studied. Predicting persistence on the basis of seed size and seed shape also has been a popular research topic lately. Studying the effects of seed weight variability on the structure of plant communities is also becoming more and more important, but no general conclusions could be drawn yet.
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Seed dispersal and habitat preference of the endangered Lesser White-fronted Goose (Anser erythropus L.) and larger goose species in the Hortobágy National Park
136-147Views:149Several studies found that waterfowl are important endozoochorous dispersal vectors for plant species. Germination of the seed content of their droppings provides valuable information on their diet and also on their role in seed dispersal. Our aim was to analyse the seed dispersal potential of the critically endangered habitat-specialist Lesser White-fronted Goose (Anser erythropus) in their autumn and spring staging areas in Hortobágy National Park. The study was supported by the LIFE10-NAT/GR/000638 project. We also studied the seed dispersal potential of larger generalist goose species foraging in the same areas, such as Greater White-Fronted Goose (Anser albifrons Scopoli) and Greylag Goose (Anser anser L.). We asked the following questions: (i) Which habitat types are the most frequently used by Lesser White-fronted Goose and larger goose species? (ii) Is the different habitat preference of Lesser White-fronted Goose and larger goose species reflected in the seed content of their droppings? (iii) Are there seasonal differences between the seed content of spring and autumn droppings? We identified the most frequently used feeding habitats. We collected 40 droppings of Lesser White-fronted Goose and larger goose species per site in April and October 2012, in total we collected 720 droppings per species. Droppings were concentrated and spread on trays filled with sterilised potting soil. Samples were germinated in a greenhouse from April to November 2013. In total we germinated 21 plant species from the goose droppings, which suggests that goose species play an important role in seed dispersal. We found that Lesser White-fronted Goose dispersed more species typical to alkali habitats, and fewer weeds compared to larger goose species. Lesser White-fronted Goose and larger goose species used a wide range of feeding habitats, thus, they play an important role in dispersing seeds between habitats along a moisture gradient. Total species number and species number of plant functional groups were higher in autumn droppings. Seed content of the droppings suggests that Lesser White-fronted Goose is confined to natural habitats, thus for the effective protection of this critically endangered species it is crucial to preserve its natural feeding habitats.
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The role of clothing in antropochorous seed dispersal
77-86Views:148Humans play an increasing role in seed dispersal. Through human help, seeds can bridge distances which otherwise would not be possible. The most important human-mediated dispersal types are: the spread on clothing, shoes and vehicles. The effect of these dispersal types can be combined in many cases. During dispersal with clothing, the seeds attach to cloths, but its probability depends on whether the seeds or other parts of the plant have morphological characteristics which make the attachment possible (e.g. hooks, hairs, spikes) and on the adhesion characteristics of the clothing (cotton/nylon, drill/cotton). This way, cloth-dispersal can be considered analogous to epizoochory. In our review, we evaluated the publications about human-mediated seed dispersal on cloths. In total we have found twelve experimental and field studies on the topic. So far, seeds of 449 species have been documented to be able to spread on clothing worldwide, out of the 449 species, 262 occur in Hungary. With future studies, these numbers will be increasing considerably. The average dispersal distance of the seeds was estimated between 150 and 5000 m, but the distance could be significantly increased, if means of transport are used during the dispersion. According to the results, the seeds of weed and invasive plants are dispersed most frequently on clothing (87% of all species, 26% of species occurring in Hungary). These cause serious damage worldwide. We emphasise that people should pay attention to the type of clothing, when they are visiting remote and unique nature reserves. For instance, waterrepellent foot wears could significantly reduce the adhesion of the seeds therefore it can prevent unintended seed dispersal. Further investigations are needed to find solutions to these problems, especially in regions with lack of these studies, such as in Europe, South America, Asia and Africa.
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New occurrence of Myricaria germanica in a Hungarian gravel pit
60–63Views:186This paper reports the second Hungarian synanthropic occurrence of the rare Myricaria germanica. One flowering individual was found in a gravel pit near Hejőpapi (NE Hungary). The closest known population of the species is 60 km far from newly found locality. This occurrence indicates effectivness of anemochory. It seems, that abandoned gravel pits may be potential habitats of this threataned shub species.
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Contributions to the flora of the Heves–Borsod and Uppony Hills and adjacent territories
173–226Views:147Results of nearly two decades of floristic research in the territory of Heves–Borsod Hills (Tarna-vidék) and the northern foreground of the Bükk Mts are presented in this paper (altogether 4421 records; BÁ: 1665, SJ: 2752). Several old literature records – partly supported by vouchers – are confirmed, e.g. Hypericum elegans and Lappula heteracantha from the Uppony Gorge, as well as Cephalaria transsylvanica, Cypripedium calceolus, Diplotaxis erucoides and Plantago indica from the Heves–Borsod Hills and the northern foreground of the Bükk Mts. Other former literature records (partly from the authors) are revised. These revisions are mainly due to changes in taxonomic concepts of some genera in new keys (Carex, Chamaecytisus, Epipactis, Molinia, Sorbus). Old literature and herbarium records of other significant taxa (Onosma visanii, Scutellaria columnae, Sorbus sp., Utricularia bremii/minor) are revised too. The new occurrence of Ferula sadleriana in the Uppony Gorge is probably the result of intentional seed dispersal. Of the many rare plants listed in our paper some are new for the flora of the region under study: Agrimonia procera, Alchemilla micans, Asplenium adiantum-nigrum, Astragalus austriacus, A. exscapus, Blysmus compressus, Carex appropinquata, C. cespitosa, Catabrosa aquatica, Centarea indurata, Dactylorhiza × aschersoniana, Epipactis voethii, Epipogium aphyllum, Equisetum hyemale, Festuca drymeja, Gagea bohemica, Glyceria nemoralis, Hesperis sylvestris, Myosotis caespitosa, Phegopteris connectilis, Platanthera chlorantha, P. × hybrida, Rosa gizellae, Scilla kladnii, Senecio doria, Solanum villosum, Taraxacum palustre, Triglochin palustre. Two phytocoenological relevés representing the habitats of Myosotis caespitosa and Spiraea media are presented. Currently known local distribution of some montane and forest-steppe elements are shown on maps.