Primary succession on lava domes on Terceira (Azores)
Clima, Ambiente e Paisagem
Elias R. B. & Dias E. 2004. Primary succession on lava domes on Terceira (Azores). Journal of Vegetation Science, 15: 331-338.
: Hansen & Sunding (1993); Schäfer (2002).: Bio-area; Direct succession; Oceanic island; Soil nutrient; Succession rate; Vegetation structure; Zoom effect.This is a special type of direct succession that takes place mainly through an increase in biomass and structural complexity. We observed small wooded areas in the fissures of very young domes that are samples of later successional forests – a phenomenon that we call ‘zoom effect’.Vegetation attributes were consistent with the successional stage of each dome in the primary sere; however, the geomorphologic units did not follow the same pattern. The influence of the rates of plant colonization and soil formation are responsible for the decrease of the successional rates from footslopes, to summits, to slopes. The vegetation successionally changes from Juniperus scrub, to Juniperus wood and forest, and there is little species replacement since the similarity in species composition is high between the 3 domes.Three comparable domes of 240, 370 and 2080 yr old were selected. Data on floristic composition, vegetation bioarea (area occupied by plant species in transects), structure, demography and soil nutrients were collected. Quantitative and qualitative changes along the succession gradient were also analyzed.Terceira Island, Azores (Portugal).Are the vegetation attributes significantly different among lava domes and among geomorphologic units as a result of age and soil features? Are the successional rates equal in all the geomorphologic units of the domes? Are the colonizer species of lava domes totally replaced by other species in the late successional stages?
Sexta, 31 Dezembro, 2004
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