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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

  136-147

  Katalin Tóth

  Dávid Bogyó

  János Tar

  Orsolya Valkó

  Views:

  170

  Several 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.

• Specific variability and ecological meaning of seed weights

  295-330

  Judit Sonkoly

  Attila Molnár V.

  Péter Török

  Views:

  189

  There 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.