Mortality and recruitment of trees in a secondary montane rain forest in Southeastern Brazil

Abstract

Mortality and recruitment rates were obtained for tree species over a 5.6 year period in a 1-ha fragment of secondary montane rain forest in Southeastern Brazil. All plants with a diameter at breast height (dbh) > or = 8 cm were sampled in 1989-1990 and 1995. There was an increase from 90 to 96 species, and 669 ind./ha to 749 ind./ha over the period. The mortality rate of 1.67%/yr was similar to findings for other forests, while recruitment of 3.46%/yr was the highest rate reported. Both mortality and recruitment were significantly higher in the smaller dbh classes. Recruitment was higher among rare species, and the relatively slow-growing species had significantly higher mortality rates. Differences between species dynamics were marked. Species with high values of lambda were mainly early successional and understorey trees but some understorey species also suffered a marked population decline. The classification system of species in response to light which divides understorey species into "partial shade-bearers" and "shade-bearers" groups showed to be the most suitable to the obtained results. The results suggest that this forest is undergoing a process of recovery from past disturbance.

Tree population and community dynamics in a Brazilian tropical semideciduous forest

“…This oscillation is obvious on a scale of small forest patches because of local sylvigenetic cycles, but when it occurs over wider areas, climatic fluctuations may also be important (Phillips & Gentry 1994). Disturbance of various kinds is commonly the chief cause of forest instability and this may involve floods, windstorms, fire, landslides, drought, and human intervention (Condit et al 1995, Laurance et al 1998, Whitmore & Burslem 1998, Gomes et al 2003, Damasceno Junior et al 2004, Werneck & Franceschinelli 2004. This poses the question of whether the imbalance found for the studied forest resulted either from climatic fluctuation or disturbance by the great flood of 1992.…”

“…This is coherent with the building up phase of forest regeneration already indicated by the overall thinning out process discussed above. The retreat or slower expansion of light-demanding relative to that of shade-tolerant species has already been associated to post-disturbance regeneration phases (Oliveira Filho et al 1997, Gomes et al 2003, Werneck & Franceschinelli 2004.…”

“…Based on Sheil et al (1995), Sheil & May (1996) and Gomes et al (2003), we assumed that changes in population size per time interval are a constant proportion of the initial population and calculated mean annual rates of mortality (M) and recruitment (R) using the exponential expressions: M = {1 -[(N 0 -m)/N 0 ] 1/ t } × 100, and R = {[(N 0 + r)/N 0 ] 1/ t -1} × 100, where N 0 is the initial population count, m is the number of deaths, r is the number of recruits and t is the time elapsed between surveys. As in Oliveira Filho et al (1997) and Werneck and Franceschinelli (2004), we also obtained the rates of loss (L) and gain (G) of tree basal area using the equations L = {1 -[(AB 0 -AB m -AB d )/ AB 0 ] 1/ t } × 100, and G = {[(AB 0 + AB r -AB g )/N 0 ] 1/ t -1} × 100, where AB 0 is the initial population basal area, AB m is basal area of dead trees, AB d is the basal area decremented by surviving trees (through breaking and stem decay), AB r is the basal area of recruits, and AB g is the basal area incremented by surviving trees.…”

Estrutura e composição de um trecho de Mata Atlântica no Parque Estadual das Fontes do Ipiranga, São Paulo, SP, Brasil

“…A. sidifolia é espécie tipicamente pioneira e heliófi la (Gomes et al 2003), sendo quase inexistente em ambientes climácicos; como espécie pioneira, possui característica de crescimento rápido, tanto em altura como em espessura (Reitz et al 1978), o que pode ter infl uenciado no cômputo do diâmetro, densidade e consequentemente na área basal. Já Syagrus romanzoffi ana (Cham.)…”

Composição florística da Reserva Municipal de Santa Genebra, Campinas, SP

“…As espécies arbóreas e arbustivas foram enquadradas em classes sucessionais (Budowski 1965) de acordo com as características ecológicas observadas em campo e segundo dados disponíveis de outros autores (Carvalho 1994, Bernacci & Leitão Filho 1996, Gandolfi et al 1995, Toniato & Oliveira-Filho 2004. Neste trabalho, as espécies de estádios finais de sucessão foram denominadas como secundárias tardias e não como climácicas, pois em função da deciduidade, praticamente nenhuma espécie arbórea de florestas semideciduais paulistas apresenta as características descritas para as espécies climácicas encontradas nas florestas pluviais tropicais (Gomes et al 2003). Arvoretas e arbustos de estádios finais de sucessão, com ocorrência característica sob o dossel da floresta, foram classificados como tolerantes à sombra de sub-bosque.…”