Ants accelerate succession from mountain grassland towards spruce forest |
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Authors: | Blanka Vlasáková Jana Raabová Tomá? Kyncl Petr Dostál Marcela Ková?ová Pavel Ková? Tomá? Herben |
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Institution: | 1. Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ‐128 01 Praha 2, Czech Republic;2. Department of Botany, National Museum, Zámek 1, CZ‐252 43 Pr?honice, Czech Republic;3. E‐mail raab@gmail.com;4. Institute of Botany, Academy of Sciences of the Czech Republic, CZ‐252 43 Pr?honice, Czech Republic;5. E‐mails kyncl@dendrochronologie.cz;6. dostal@ibot.cas.cz;7. kovarova@ibot.cas.cz;8. herben@ibot.cas.cz;9. E‐mail kovar@natur.cuni.cz;10. Institute of Botany, Academy of Sciences of the Czech Republic, CZ‐252 43 Pr?honice, Czech Republic |
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Abstract: | Question: What is the role of mound‐building ants (Lasius flavus) in successional changes of a grassland ecosystem towards a spruce forest? Location: Slovenské Rudohorie Mountains, Slovakia; ca. 950 m a.s.l. near the Obrubovanec point (1020 m a.s.l.; 48°41′N, 19°39′E). Methods: Both chronosequence data along a successional gradient and temporal data from long‐term permanent plots were collected on ants, spruce establishment, and vegetation structure, together with additional data on spruce growth. Results: There are more spruce seedlings on ant mounds (4.72 m?2) than in the surrounding vegetation (0.81 m?2). Spruce seedlings grow faster on these mounds compared to surrounding areas. The first colonization wave of seedlings was rapid and probably occurred when grazing prevailed over mowing. Ant colony presence, mound volume, and plant species composition change along the successional gradient. Mounds become bigger when partly shaded but shrink in closed forest, when ant colonies disappear. Shade‐tolerant acidophylic species replace grassland plants both on the mounds and in surrounding areas. Conclusions: The massive occurrence of Lasius flavus anthills contributes to a runaway feedback process that accelerates succession towards forest. The effect of ants as ecosystem engineers is scale‐dependent: although they stabilize the system at the scale of an individual mound, they may destabilize the whole grassland system over a longer time scale if combined with changes in mowing regime. |
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Keywords: | Anthills Chronosequence Disturbance Lasius flavus Mowing Permanent plot |
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