Humus profiles and successional development in a rock savanna : a 1 micromorphological approach pointing to fire as a disturbance event 2 ( Nouragues inselberg , French Guiana
نویسندگان
چکیده
1 2 The common development of vegetation and soil is a central question of plant succession. We 3 asked whether places where aerial parts of woody vegetation die and accumulate on the 4 ground (zones of destruction or 'micro-chablis') played a role in the successional 5 development of vegetation patches on tropical inselbergs and whether causes could be 6 inferred from the analysis of the organic matter accumulated along a successional gradient. 7 The study was conducted in French Guiana (South America). Nine humus profiles (each 8 comprised of a varying number of layers) were selected in shrub thickets (~1a each) 9 representative of three vegetation types of the rock savanna: canopies of pure Clusia minor 10 (Clusiaceae), C. minor in mixture with Myrcia saxatilis (Myrtaceae) and zones of destruction. 11 A count point optical method for small soil volumes was used to measure under a dissecting 12 microscope the volume ratio of each kind of humus component (107 categories) in the 62 13 layers thus sampled. Micromorphological data were analysed by correspondence analysis 14 (CA). Humus profiles varied according to canopy trees and revealed traits of the past and 15 trends for the future of the plant succession. Zones of destruction differed from other humus 16 profiles by lack of OL and OF horizons and by the presence of charred material, which 17 establishes the role of spatially limited fires or lightning impacts in the cyclic development of 18 vegetation patches.
منابع مشابه
Humus profiles and successional development in a rock savanna (Nouragues inselberg, French Guiana): a micro-morphological approach infers fire as a disturbance event
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24 25 The combined effects of isolation within an unfavourable matrix and vegetation 26 development were studied in patches of scrub vegetation on a tropical inselberg (Nouragues, 27 French Guiana). Three thickets ~10 m 2 area were sampled, located at ~30 m distance from 28 each other, in which the same vegetation types were present at less than 3 m distance: 29 canopies of Clusia minor (Clusia...
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