Forest Dynamics Monitoring
Soil microbes play an essential role in forest ecosystems. The development of the high-throughput sequencing method provides an invaluable opportunity to further understand soil microbial communities. In this study, we investigated soil bacterial diversity in the Baotianman forest using the Illumina Miseq platform. Results showed that in the 31 soil sampling points, the number of bacterial taxa detected at different classification levels increased with increasing number of sampling points. When all 31 samples were considered, the number of relative bacterial groups included 45 phyla, 163 classes, 319 orders, 495 families, 785 genera and 42,632 OTUs. The mean values of relative bacterial taxa in the 31 samples were 34.2 phyla, 114.7 classes, 215.2 orders, 323.7 families, 446.6 genera, and 5,924.7 OTUs. At the classification level of phylum, class and order, the dominant groups were Proteobacteria (38.30%), α-Proteobacteria (18.08%), and Rhizobiales (10.62%), respectively. These preliminary findings suggest that Baotianman forest soils have high levels of bacterial diversity to some degree and provide basic information and knowledge to further understand the relationship between soil bacterial diversity and plant diversity and other related scientific questions.
The individual species-area relationship (ISAR) can be used to estimate the effects of individual species (accumulator, repeller, or neutral) on neighboring biodiversity at different spatial scales. The effects of individual species with different sizes (diameter at breast height classes, DBH classes) on neighboring species diversity are still an unresolved question although several papers have addressed this question by using the ISAR. In this study, we compared ISARs of nine types (all to all, all to adult, all to young, adult to all, adult to adult, adult to young, young to all, young to adult and young to young); “young to adult” represents that ISAR of young individuals of target species to adult individuals of neighboring species in a 1 ha deciduous broad-leaved forest in Baotianman National Nature Reserve, Henan Province. We tested the following hypotheses: (1) the adult individuals (DBH ≥ 10 cm) of target species have greater influence on the biodiversity of their neighbors than the young (DBH < 10 cm); (2) the individuals of the same species or the same size class have greater influence on neighboring young tree diversity than adult tree diversity; (3) most species are neutral in the Baotianman deciduous broad-leaved forest. The results showed that the effects of tree species with different sizes on neighboring tree diversity are scale-based and also affected by the size of the neighbor tree. The results supported the hypothesis that individuals of the same species or the same size have greater influence on neighboring young tree diversity than on neighboring adult tree diversity; but did not support that the adult individuals of focal species have greater influence on neighboring tree diversity than young individuals. The results also indicated that most species are neutral at spatial scales of 1-10 m in the Baotianman forest; multiple accumulator or repeller species were detected at some scales. The results will contribute to our understanding of the role of specific species on biodiversity and community maintenance mechanism.
Subtropical evergreen broad-leaved forest (EBLF) is the zonal vegetation of the Chinese subtropical region, among which the most typical and widely distributed type is mid-subtropical EBLF. To explore how the 2008 ice-storm affected the short-term dynamics of mid-subtropical EBLF, we examined the community structure and species composition pre and post the ice storm of the 24 ha forest dynamics plot in Gutianshan. We found that although the DBH size class structure was highly consistent pre and post the ice storm, community level recruitment was low and mortality was high. Results of community dynamics analyses conducted at various grain size scales implied general depressions, despite the different rates of change between habitats. Species abundance and ABH (area at breast height) both decreased but species frequency and IV (importance value) did not change. Species in abundance, ABH, frequency and IV were highly consistent pre and post the ice storm. The results imply that the 2008 ice storm negatively impacted the short-term dynamics of the EBLF community in Gutianshan. The severity of impact was associated with stem DBH and topography. However, the community structure of this old-growth forest showed its considerable resistance to ice storm disturbance.
The flowering phenology of plants is influenced by climatic, phylogenetic and functional constraints. To our knowledge, this is the first study to examine the influence of these three factors on flowering phenology simultaneously. In order to investigate the relative impact of each of the three factors, we tested their importance in describing five-year of flowering data using 130 seed traps in a 24 ha plot in the Gutianshan forest in eastern China. Flowering of the subtropical evergreen forest peaked in May. The community flowering pattern was significantly correlated with climatic variables including temperature and rainfall. According to DNA barcoding data, closely related species had similar flowering dates. The mean flowering dates were also associated with maximum tree height, but not with pollinator mode, flower color, seed mass and dispersal mode. DNA barcoding data for testing phylogenetic constraint is strongly recommended in future studies. Our findings also suggest that climatic variables, phylogeny, and functional traits were associated with the community flowering pattern. Simultaneously considering these three factors will enhance our understanding of plant phenological patterns.
The zonal vegetation type of subtropical China is evergreen broad-leaved forest (EBLF). However, due to long term anthropogenic disturbance, primary EBLF is now scarce in this region; most of the EBLFs exist as secondary forests. Therefore, to preserve the regional forest biodiversity, it is important to understand the mechanisms underlying biodiversity maintenance of the regional secondary EBLF. One method for examining the mechanisms of forest biodiversity maintenance is to investigate the species composition and community structure on the basis of a large forest dynamics plot (FDP). According to protocols of Center for Tropical Forest Science (CTFS), we established a 9 ha FDP in the secondary EBLF of Wuyanling National Nature Reserve in Zhejiang Province, China, during 2011-2012. Here, we carried out analysis on species composition (e.g., importance value), community structure (e.g., floristic composition, size-class structure), and spatial distribution of woody plants with diameter at breast height (DBH) ≥1 cm. Results indicated that there were 71,396 woody plant individuals belonging to 200 species, 92 genera and 47 families within the FDP. The dominant families were Fagaceae, Lauraceae, Theaceae, Aquifoliaceae, Ericaceae and Symplocaceae. There were slightly more tropical elements than temperate elements found both at family and genus level. DBH size-classed community structure was reverse ‘J’ shaped, indicating abundant regeneration. Dominant species showed various shapes, such as reverse ‘J’, skewed or waved shapes, but no signs of population decline. Dominant species showed habitat priority and aggregated distribution patterns possibly related to habitat conditions, suggesting that habitat heterogeneity might be responsible to the spatial distribution of the dominant species in this FDP.
The herbaceous layer is an important component of forest ecosystems and plays an important role in maintaining forest biodiversity. To understand the mechanisms shaping the forest herb community patterns over multiple growing seasons, we used herbaceous data collected in a 25 ha broad-leaved Korean pine (Pinus koraiensis) mixed forest plot in Changbai Mountain, Northeast China and fitted species abundance distributions (SADs) using different models. We used both pure statistical models including log-normal, log-series, and mechanistic models, including two niche models (broken-stick and niche preemption) and two neutral models (metacommunity zero-sum multinomial distribution and Volkov model). Further, we applied the AIC and Kolmogorov-Smirnov tests to compare the goodness-of-fit of these models. Our results showed: (1) The observed SADs of the herb layer varied by season. While there were similar proportions of rare and common species in spring, there were more species with moderate abundances in summer and more rare species in autumn. (2) The best-fitting models of SADs were similar in different seasons. In our analyses, the log-series model was the best pure statistical model across the three seasons. For the mechanistic models, neutral models performed better at explaining patterns of SADs than niche models. The metacommunity zero-sum multinomial distribution model was the best model in spring and summer and the Volkov model was the best one in autumn. This indicates that stochastic processes may play a dominant role in maintaining the herb species abundance distributions. Our study showed that although the SAD patterns varied over growing seasons for the herb layer in the broad-leaved Korean pine mixed forest, the underlying mechanisms governing these patterns are similar and neutral models always perform better than niche models in fitting the SADs.
Biodiversity Committee, CAS
Botanical Society of China
Institute of Botany, CAS
Institute of Zoology, CAS
Institute of Microbiology, CAS
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