Alternative successional pathways in the Amazon Basin

Citation
Rcg. Mesquita et al., Alternative successional pathways in the Amazon Basin, J ECOLOGY, 89(4), 2001, pp. 528-537
Citations number
43
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Environment/Ecology
Journal title
JOURNAL OF ECOLOGY
ISSN journal
0022-0477 → ACNP
Volume
89
Issue
4
Year of publication
2001
Pages
528 - 537
Database
ISI
SICI code
0022-0477(200108)89:4<528:ASPITA>2.0.ZU;2-4
Abstract
1 Successional pathways were evaluated in two Amazonian secondary forest co mmunities with different land-use histories. Sites which had been clearcut without subsequent use were dominated after 6-10 years by the pioneer genus Cecropia (Moraceae), whereas those used for pasture before abandonment wer e dominated by the pioneer genus Vismia (Clusiaceae). 2 There were 58 plant families and 300 species identified in Cecropia stand s but only 43 families and 147 species were identified in Vismia stands. Th ere were 77 species in common (Sorensen similarity = 0.34). 3 Differences in species number and composition of recruiting individuals b etween stand types were significant and were a function of the dominant pio neer genus, stem density, distance from primary forest, and land-use histor y. Regeneration under Vismia canopy was dominated by small Vismia individua ls (25% of plants < 2 cm basal diameter), whereas regeneration under Cecrop ia canopy was more diverse and did not include a single young Cecropia. 4 The number of regenerating plants in both secondary stand types dropped o ff sharply with distance (5, 25, 50, and 100 m) from primary forest, sugges ting that seed dispersal was limiting plant recruitment. Species richness a lso declined with distance and could be explained by the decline in plant d ensity. Species richness in Cecropia stands increased linearly with plant d ensity, but in Vismia stands the richness increase with density was a decel erating function. 5 For the central Amazon, secondary succession involves a more rapid return of primary forest species if deforestation is not followed by use as pastu re before abandonment.