Dynamics and Prediction of Diametric Structure in Two Atlantic Forest Fragments in Northeastern Brazil

Abstract

-Monitoring analyses aim to understand the processes that drive changes in forest structure and, along with prediction studies, may assist in the management planning and conservation of forest remnants. The objective of this study was to analyze the forest dynamics in two Atlantic rainforest fragments in Pernambuco, Brazil, and to predict their future forest diameter structure using the Markov chain model. We used continuous forest inventory data from three surveys in two forest fragments of 87 ha (F1) and 388 ha (F2). We calculated the annual rates of mortality and recruitment, the mean annual increment, and the basal area for each of the 3-year periods. Data from the first and second surveys were used to project the third inventory measurements, which were compared to the observed values in the permanent plots using chi-squared tests ( = 0.05). In F1, a decrease in the number of individuals was observed due to mortality rates being higher than recruitment rates; however, there was an increase in the basal area. In this fragment, the fit to the Markov model was adequate. In F2, there was an increase in both the basal area and the number of individuals during the 6-year period due to the recruitment rate exceeding the mortality rate. For this fragment, the fit of the model was unacceptable. Hence, for the studied fragments, the demographic rates influenced the stem density more than the floristic composition. Yet, even with these intense dynamics, both fragments showed active growth.Keywords: Environmental monitoring; Markov; Plant biometrics.DINÂMICA E PREDIÇÃO DA ESTRUTURA DIAMÉTRICA DE DOIS FRAGMENTOS DE FLORESTA ATLÂNTICA NO NORDESTE DO BRASIL RESUMO -Análises de monitoramento possibilitam o entendimento dos processos que levam a mudanças na estrutura da floresta e, juntamente com estudos de predição, podem auxiliar no planejamento do manejo e conservação de remanescentes florestais. O objetivo deste trabalho foi analisar a dinâmica de dois fragmentos de Floresta Atlântica no estado de Pernambuco, Brasil e predizer a estrutura diamétrica, empregando o modelo de cadeia de Markov. Foram utilizados dados do inventário florestal contínuo com três ocasiões, para dois fragmentos florestais, com 87 ha (F1) e 388 ha (F2). Foram calculadas taxas anuais de mortalidade e recrutamento, incremento médio anual e área basal para todos os períodos analisados. Os dados obtidos na 1ª e 2ª ocasiões foram utilizados para realizar a projeção para 3ª ocasião, que foi comparada aos dados observados nas parcelas permanentes empregando o teste Qui-quadrado ( = 0.05). Em F1, houve redução 308Revista Árvore, Viçosa-MG, v.40, n.2, p.307-317, 2016 BATISTA, A.P.B. et al.no número de indivíduos, devido às taxas de mortalidade que foram superiores ao recrutamento; porém, houve um ganho de área basal. Nesse fragmento, o ajuste do modelo de Markov foi satisfatório. Em F2, houve aumento na área basal e no número de indivíduos no período de seis anos em função da taxa de recrutamento superior à mortalidade. O modelo não foi efica...

Natural Regeneration Dynamics of Mora paraensis (Ducke) Ducke in Estuarine Floodplain Forests of the Amazon River

“…A transition matrix was used to evaluate the dynamics of regenerating individuals of M. paraensis between height classes [39,40]. Data collected in 2012, 2013 and 2015 were used to estimate the probability of movement of seedlings between eight height classes: class one was recruitment or entry (R), classes two to seven represent subsequent increments of 1 m, and class eight was mortality (M).…”

“…Data collected in 2012, 2013 and 2015 were used to estimate the probability of movement of seedlings between eight height classes: class one was recruitment or entry (R), classes two to seven represent subsequent increments of 1 m, and class eight was mortality (M). Each transition matrix was calculated based on the absolute frequency of individuals in the height classes, in the years for which data were collected, analysed in pairs: 2012-2013 and 2013-2015 [39,40].…”

“…However, this apparent population stability may, in fact, reflect the shorter interval between samples (one rather than two years). In previous studies that have used transition matrices to evaluate the dynamics of individual trees between diametric size classes in natural forests, some authors have observed that the probability of remaining in the same class is higher in shorter time periods: two years [42], three years [40] and four years [54]. As such, when the observation period is shorter, the probability of remaining in the same class is higher, and when the period is longer, the probability of transitioning between classes increases.…”

Prognosis of the Diameter Distribution and Carbon Stock in a Secondary Atlantic Forest by Markov Chain

“…Tabela 3 -Volume (m 3 ha -1 ), biomassa (Mg ha -1 ) e estoque de carbono (MgC ha -1 ) para os grupos ecológicos (pioneiras e não pioneiras) e para o fragmento florestal, por classe diamétrica. in terms of tropical forest (Batista et al, 2016). Another point that contributed to the efficacy of the projection was the absence of disturbances in the fragment, given that this can affect the prognosis and generate imprecise and tendentious estimations (Xie et al, 2013).…”

“…Given this scenario, studies focusing on growth and yield modeling are extremely important for the biodiversity and ecosystem service maintenance of these forest fragments (Lima and Leão, 2013). Independent of its structural complexity, the aim of modelling is to allow the projection of production into the future based on current conditions (Chassot et al, 2011), with diameter distribution models, in particular the transition matrix, being the most common for tropical forests (Teixeira et al, 2007;Vasconcelos et al, 2009;Batista et al, 2016).…”