Effect of disturbance intensity on regeneration mechanisms in a tropical dry forest

Abstract

We examined the effect of disturbances of varying intensity on the dominant modes of regeneration among woody plants in tropical dry forest in lowland Bolivia. Seed survival and density, mortality, height, crown area, and basal diameters of seedlings and sprouts were compared among four treatments of varying disturbance intensity (high-intensity burn, lowintensity burn, plant removal, and harvesting gap) over a period of 18 months following treatments. High-and low-intensity burns reduced densities of viable seed by an average of 94 and 50%, respectively. Tree seedlings were more abundant than tree sprouts in all treatments. There were few differences in seedling density among treatments. Sprouts were most common in the plant removal and low-intensity burn treatments than in harvesting gap and high-intensity burn treatments. Seedling mortality was higher than sprout mortality during the first year following treatments. Sprouts were taller, had more stems per individual, larger crown areas, and larger basal diameters than seedlings. Origin of sprout differed among treatments. Eighteen months following treatments, 85% of individuals >2.5 m tall were sprouts. Most seedlings >2.5 m tall after 18 months had established in high-intensity burn treatments. Sprouting individuals dominated regeneration after all treatments, however, in high-intensity burn treatments, sprouts were relatively less dominant due to smaller sprouts and larger seedlings after high-intensity burns. #

The role of root buds in the regeneration of Casearia sylvestris Swartz (Salicaceae) in the cerrado, São Carlos, São Paulo state, Brazil

“…Based on the population under study, the prevailing reproductive strategy was vegetative, 85% of the plants analyzed arising from root buds. Sprouting from roots is an important natural mechanism for regeneration just after a natural disturbance, because it quickly provides new plant cover in affected areas (Paciorek et al 2000, Kennard et al 2002. Cerrado species have become adapted to fi re events during evolution.…”

Dinâmica da comunidade arbórea em uma floresta estacional semidecidual sob queimadas recorrentes

“…A recuperação da vegetação após o fogo pode variar dependendo da intensidade e duração do incêndio (Keeley et al 2003). Em alguns casos, os incêndios podem inibir o ciclo de regeneração da floresta (Kennard et al 2002;Laurance 2003;Otterstrom & Schwartz 2006), enquanto em outros esses distúrbios, quando em intensidade intermediária, podem ser importantes para a manutenção de um grande número de espécies (Hubbell et al 1999), uma vez que provoca a reversão das comunidades a estados sucessionais iniciais, nos quais espécies previamente excluídas por competição, voltam a se estabelecer (Sheil & Burslem 2003).…”

Relative importance of various regeneration mechanisms in different restoration stages of Quercus variabilis forest after selective logging

“…In our study, stump sprouts of Chinese cork oak were taller and bigger than true seedlings in both the logged and unlogged stands; this result was consistent with those of previous studies. The greater height and basal diameter of stump sprouts caused by rapid development could be attributed to the established root system, which could offer more surface area for water and nutrient uptake (Cruz et al, 2002;Kennard et al, 2002), thereby providing sprouts a competitive advantage for occupancy, survival, and dominant regeneration position in forest recovery (Lockhart and Chambers, 2007). The lower height development of true seedlings may be explained by the fact that seedlings invest great nutrition and energy to develop a completed root system first, whereas repeated shoot dieback caused by herbivores can result in lower heights (Ky-Dembele et al, 2007).…”

“…The relative importance of these two regeneration mechanisms during forest recovery was determined by species composition and biology of disturbed forest, and the origin and intensity of disturbance (Kennard et al, 2002;Ky-Dembele et al, 2007). The regeneration of some forests after disturbance, such as burning, is dominated by asexual recruits (e.g., sprouts) rather than shoots established from seeds Yaoqin- Xue et al / Forest Systems (2014) 23(2): 199-208 (Hoffmann, 1998;Kennard et al, 2002).…”

“…The regeneration of some forests after disturbance, such as burning, is dominated by asexual recruits (e.g., sprouts) rather than shoots established from seeds Yaoqin- Xue et al / Forest Systems (2014) 23(2): 199-208 (Hoffmann, 1998;Kennard et al, 2002). In other forests, such as the Nazinon forest, sexual reproduction is the predominant mechanism after selective cutting (Ky-Dembele et al, 2007).…”