Secondary Succession in the Tropical Lowland Rainforest Reduced the Stochasticity of Soil Bacterial Communities through the Stability of Plant Communities

Abstract

The effects of natural succession on plant and soil bacterial communities were previously established, but changes in plant and soil bacterial communities and their response to soil properties are not well characterized in different stages of secondary forest succession, especially in tropical regions with endemic plant species. We investigated the dynamics of plant communities, soil properties and the structure of soil bacterial communities at sites representing 33 (early successional stage), 60 (early-mid successional stage) and 73 (mid successional stage) years of secondary succession in the tropical lowland rainforest of Hainan, China, by using16S rRNA high-throughput sequencing. From the perspective of plant composition, the number of families, genera and species were increasing along with the progress of succession. Additionally, the changes in the ranking of important values along with the progress of the forest succession were consistent with the niche width calculated by the previous stage of the plant community. The results of niche overlap, Pearson’s correlation and Spearman’s rank correlation coefficients and significance indicated that in the early stage of succession, tree species did not fully utilize environmental resources. Then, as time went by, the number of negative correlations of plants in the early-mid stage was more than that in the mid stage of succession. Significant differences were found in the species richness of soil microorganisms among the three successional stages. Nutrient contents in early successional stage rainforests were less abundant than in early-mid and mid forest soils. The influence of soil nutrient concentration, particularly N and P content, on soil bacterial composition at the phylum level was larger in the early-mid stage than in the mid stage. The stochasticity of the soil bacterial community at the early successional stage of the rainforest was significantly higher than that at mid stage. Overall, as the diversity of plant communities increased, the competition decreased, the soil nutrient content changed and the stochasticity of soil bacterial communities decreased as a result of forest succession.

Secondary Succession Altered the Diversity and Co-Occurrence Networks of the Soil Bacterial Communities in Tropical Lowland Rainforests

“…Tropical lowland rainforest is the type of vegetation found here. Hainan Island is located on the tropics’ northern edge, is an area of tropical marine monsoon climate, with an average annual rainfall of 1800 mm and a mean annual temperature of 24.5 °C [ 18 ]. The field soil is Oxisol in the USDA Soil Taxonomy.…”

“…16S rRNA genes of distinct regions V4-V5 were amplified used specific primer 515F and 907R synthesized by Invitrogen (Invitrogen, Carlsbad, CA, USA) with 12bp barcode. PCR amplification, gel extraction, and sequence processing were operated as described previously by Hu et al [ 18 ].…”

“…At the same time, the forest soil in the later succession has a higher water retention capacity because of the continuous development of the plants’ root system [ 17 ], which may affect the growths of soil bacterial communities composition, structure, and diversity. With the succession of the forest, the stand canopy density continued to rise, and this had a significant impact on the light-sensitive bacterial abundance and community composition [ 18 ].…”

Tropical invertebrate community assembly processes are robust to a gradient of land use intensity

“…There is broader conceptual and empirical support for determinism having higher relative importance in logged forests, which tend to have harsher environmental conditions compared to primary forests. Harsher environmental conditions can inflict a deterministic filter on community assembly, thus increasing the importance of deterministic processes, which has been demonstrated across a variety of taxa and regions (Chase 2007, Lepori & Malmqvist 2009, Chase & Myers 2011, Ding et al 2012, Wearn et al 2019, Li et al 2021, Hu et al 2022).…”

Resilience of tropical invertebrate community assembly processes to a gradient of land use intensity

“…Döbert et al (2017) showed that understorey plant communities in tropical Bornean forests tend to be more stochastically assembled at higher logging intensities, whereas Wearn et al (2019) showed that deterministic environmental control on mammal community assembly is higher in logged forest compared to old‐growth forest. There is broad conceptual and empirical support for deterministic environmental filtering on community assembly becoming more important in harsher environmental conditions (Chase 2007, Lepori and Malmqvist 2009, Chase and Myers 2011, Ding et al 2012, Wearn et al 2019, Li et al 2021, Hu et al 2022). We therefore hypothesise that stochasticity will become less important with increasing logging intensity.…”