The succession characteristics and its driving mechanism of plant community in karst region, southwest China

Abstract

Vegetation restoration is the key step of desertification prevention and ecological rehabilitation in the karst region in Southwest China. A sound understanding of the vegetation composition, species diversity, and structural variation with succession is of great significance for vegetation protection and rehabilitation. However, until now, a systematic synthesis of information was not available for this region. In this study, we thoroughly collected the relevant data from the literature and unpublished data from Huanjiang Observation and Research Station of Karst Ecosystem, Chinese Academy of Sciences. We then systematically analyzed the data to determine the dynamics and driving mechanisms of plant community succession in the karst region of southwest China. To facilitate the analyses, the whole region was divided into northern subtropical, mid http: / / www.ecologica.cn subtropical, southern subtropical, and northern tropical regions. The height of the plant community and vegetation coverage increase in the mean annual temperature and precipitation or with a decline in altitude in subtropical and northern tropical regions. Along with decreasing altitude, community structure improved, however, the community density, number of families, genera, species, and diversity decreased probably due to the increase in landscape homogeneity. Along the succession from grassland to shrubland, shrub / arbor mixed woodland, and to arborland, the height of the community and the coverage increased, but density decreased for the entire region. The number of families, genera, species, and diversity increased along the succession in the northern subtropical region, but these indices reached maximum in shrub / arbor mixed woodlands in the remaining three regions. The vegetation succession and distribution pattern were the result of multiple ecological processes including species evolution (speciation, migration, and extinction) , geographical differentiation and environmental factors (e.g., geology, topography, climate, soil) , and other processes. Under the impacts of natural factors (soil, climate, topography) , human disturbances, and other ecological factors, long鄄term interactions among plant individuals resulted in spatial and temporal variation of vegetation distribution at different scales and levels. The main driving forces of vegetation succession included biological factors (microbial community, physiological ecology, and growth characteristics of species) and abiotic factors (e.g., landscape heterogeneity, topography, physical and chemical properties of the soil) and their interactions. The constructive species and key specie were variable for different successional stages and regions. With vegetation development, the climax species became richer, and the key species had a tendency to be more advanced, large in size, and long鄄living. The relationship between stability and diversity of plant communities was more complex. In general, along the community succession sequence, the stability was greater for the climax communit...

Water uptake depth is coordinated with leaf water potential, water‐use efficiency and drought vulnerability in karst vegetation

“…Interestingly, most of the species showing smaller size, shallower water uptake, lower leaf δ 13 C/WUEi and extensive canopy defoliation or mortality during drought are typical pioneer, early‐successional species ( V. negundo , A. trewioides , P. fortuneana , M. repandus ) that are dominant in degraded karst areas. Conversely, the majority of the species of larger size using deeper water sources and exhibiting higher leaf δ 13 C/WUEi, moderate drought‐induced defoliation and drought survival ( S. rotundifolium , S. euosma , P. tonkinense) typically become dominant in late‐successional karst vegetation stages (Wen et al ., 2015). It thus appears that the late‐successional species of mature karst forests have undergone high selective pressure for deep rooting and heavy reliance on more temporally stable water sources.…”

“…Eleven woody plant species of contrasting life form and leaf habit were selected for assessing the impacts of experimental rainfall exclusion (Table 1). Among them, V. negundo , A. trewioides , Pyracantha fortuneana , Mallotus repandus , Schefflera octophylla and R. sinica are pioneer species typical of early‐successional vegetation stages, whereas the remaining five species ( C. biondii , Diospyros dumetorum , S. rotundifolium , S. euosma , P. tonkinense ) usually appear during middle‐ or late‐ successional stages during vegetation recovery from disturbance (Wen et al ., 2015). Three to five individuals of each target species were present in the rainfall exclusion plot and all of them were used for the ecophysiological measurements explained below.…”

Naturalization of an alien ancient fruit tree at a fine scale: Community structure and population dynamics of Cydonia oblonga in China

“…Simultaneously, however, coexisting species experience strong interspecific competition because of their similar resource requirements (Castagneri et al, 2008). In subtropical steep rocky mountain habitats (Wen et al, 2015), shrublands are dominated by S. chinensis , which is the closest relative of C. oblonga (Figure 6). In the studied community, however, the S. chinensis population is declining and gradually being replaced by C. oblonga (Figures 3 and 4), supporting the conclusion that “the naturalization of alien species severely harms closely related native species, leading to their local extinction” (Li, Cadotte, et al, 2015).…”

“…Simultaneously, however, coexisting species experience strong interspecific competition because of their similar resource requirements (Castagneri et al, 2008). In subtropical steep rocky mountain habitats (Wen et al, 2015), shrublands are dominated by S. chinensis, which is the closest relative of C. oblonga (Figure 6).…”

Common Species Maintain a Large Root Radial Extent and a Stable Resource Use Status in Soil-Limited Environments: A Case Study in Subtropical China

“…In order to satisfy the greater resource demand, larger aboveground species need to develop a relatively large root system (Westoby and Wright, 2006). Previous studies in karst regions showed that during the early stages of restoration in with infertile soil conditions, plants have not yet developed large root systems, only small shrubs can be supported to survive and thrive (Wen et al, 2015;Zhang et al, 2015), which has also been shown in non-karst studies (A. G. T, 1916;Glenn-Lewin et al, 1993;Jiang et al, 2018). In terms of leaf phenology, compared with the evergreen species, deciduous species require more resources during the rainy season because of their concentrated growth (Hasselquist et al, 2010;Nie et al, 2014b;Wang and Moore, 2014;Delzon, 2015;Salazar-Tortosa et al, 2018).…”