Diferencias en la flora herbácea y arbustiva entre claros y áreas bajo dosel en un bosque de Nothofagus pumilio en Argentina

Abstract

The distribution of herbs and shrubs under closed canopies and in two canopy gaps of different size was compared in a Nothofagus pumilio deciduous forest of Argentina. The total and the average species richness per plot were similar between the areas under the canopy and in small (maximum diameter <5 m) and medium size gaps (maximum diameter 5-10 m). Generalist species were the most numerous (46%), while obligate and facultatively shade-tolerant (heliophobous) and intolerant (heliophilous) species accounted for 19 and 15% of the species, respectively. The absence of differences in species richness may be attributed to: (1) high frequency of generalist species (2) low effect of gap formation on shade-tolerant species distribution, (3) persistence of facultatively shade-tolerant species in small gaps, (4) gap invasion by obligate shade-intolerant species. The heterogeneity of light environment beneath the canopy and the effects on gap microclimate of edge trees and gap shrubs are possible causes of these patterns. Although with variations between the different biological groups, forest species are probably tolerant to the low level of disturbance generated by the natural forest dynamics.