Floristic and structure of an Amazonian primary forest and a chronosequence of secondary succession

Abstract

The analysis of changes in species composition and vegetation structure in chronosequences improves knowledge on the regeneration patterns following land abandonment in the Amazon. Here, the objective was to perform floristic-structural analysis in mature forests (with/without timber exploitation) and secondary successions (initial, intermediate and advanced vegetation regrowth) in the Tapajós region. The regrowth age and plot locations were determined using Landsat-5/Thematic Mapper images . For floristic analysis, we determined the sample sufficiency and the Shannon-Weaver (H'), Pielou evenness (J), Value of Importance (VI) and Fisher's alpha (α) indices. We applied the Non-metric Multidimensional Scaling (NMDS) for similarity ordination. For structural analysis, the diameter at the breast height (DBH), total tree height (Ht), basal area (BA) and the aboveground biomass (AGB) were obtained. We inspected the differences in floristic-structural attributes using Tukey and Kolmogorov-Smirnov tests. The results showed an increase in the H', J and α indices from initial regrowth to mature forests of the order of 47%, 33% and 91%, respectively. The advanced regrowth had more species in common with the intermediate stage than with the mature forest. Statistically significant differences between initial and intermediate stages (p<0.05) were observed for DBH, BA and Ht. The recovery of carbon stocks showed an AGB variation from 14.97 t ha -1 (initial regrowth) to 321.47 t ha -1 (mature forests). In addition to AGB, Ht was also important to discriminate the typologies. KEYWORDS: Forest recovery; vegetation dynamics; forest structure; floristic patterns, biomass.Florística e estrutura de uma floresta primária e uma cronossequência de sucessão secundária na Amazônia RESUMO A análise de mudanças na composição de espécies e estrutura da vegetação em cronosseqüências aprimora o conhecimento sobre os padrões de regeneração após o abandono das terras na Amazônia. Nosso objetivo foi realizar análise florístico-estrutural em florestas maduras (com / sem exploração madeireira) e em sucessões secundárias (inicial, intermediária e avançada) na região do Tapajós. A idade da regeneração e os locais das parcelas foram determinados usando imagens Landsat-5 TM (1984-2012. Na análise florística, foi determinada a suficiência amostral e os índices de Shannon-Weaver (H'), uniformidade de Pielou (J), Valor de Importância (VI) e alfa de Fisher (α). Foi aplicada análise de escalonamento multidimensional não-métrico (NMDS) para ordenação de similaridade. Na análise estrutural, o diâmetro à altura do peito (DAP), altura total da árvore (Ht), área basal (BA) e biomassa acima do solo (AGB) foram obtidos. As diferenças entre tipologias dos atributos florísticos-estruturais foram verificadas utilizando os testes de Tukey e Kolmogorov-Smirnov. Os resultados mostraram aumento dos índices H', J e alfa a partir da sucessão inicial até as florestas maduras da ordem de 47%, 33% e 91%, respectivamente. O estágio avançado apresentou mais espécies em...

Natural recovery of plant species diversity in secondary forests in Eastern Amazonia: contributions to passive forest restoration

“…Previous studies have found a positive relationship between biomass recovery (which is related to basal area) and biodiversity (e.g. Marín-Spiotta et al 2007;Letcher and Chazdon 2009;Silva et al 2016, Lennox et al 2018. Overall, basal area (or related measures, such as biomass) is a good indicator of structural changes in the regenerating forests (Lennox et al 2018), such as increasing canopy cover and soil organic matter, which favour the establishment of more species.…”

“…Recovery rate of the structure and diversity of plant species in secondary forests are determined by a complex interaction between local, historical and landscape factors, as well as the regional species pool and their life history traits (Chazdon et al 2007). Forest recovery is related to several intrinsic factors, such as time since abandonment (Prata et al 2010;Silva et al 2016), land-use history (Jakovac et al 2015;Villa et al 2018), soil characteristics and landscape structure (Jakovac et al 2015;Pinho et al 2018;Do vale et al 2018).…”

Retrieving Secondary Forest Aboveground Biomass from Polarimetric ALOS-2 PALSAR-2 Data in the Brazilian Amazon

“…Field plot data were composed by two databases: 16 plots measured in this study and 26 plots measured by Silva [64] (Table 1). The sample plots were placed close to the FLONA of Tapajós on either side of the BR-163 highway, 100 km to the south of the city of Santarém (Figure 1).…”

“…Trees with a DBH ≥ 10 cm were measured in a 20 m × 100 m plot size, and trees with a DBH ≥ 20 cm were measured in a 60 m × 100 m plot size. Silva [64] carried out a field campaign between 2012 and 2013 at the same site ( Table 1). The method consisted of the collection of 23 plots (20 m × 50 m) for the SF with initial secondary succession (ISS) and intermediate secondary succession (IntSS), and three plots for the advanced SF (25 m × 100 m).…”

“…So, the classification of the SF in the ISS, IntSS, and AdvSS should not be only based on structural parameters or species richness and composition [12]. Pioneer species comprise 33% of the S and almost 40% of the N in the Santarém study site [63,64]. The most common species were Guatteria poeppigiana Mart.…”