Abstract
Identifying the species abundance distributions (SADs) in Tiankeng forests is crucial for restoring and managing degraded karst ecosystem, whereas previous studies rarely explored the differences and response of vegetation dynamics to environmental variations. The species composition and SADs of the inner and outer fringe areas of Tiankeng forest and nearby non-Tiankeng forest were compared in Southwest China. Six models were adopted to compare SADs of three habitats. Kolmogrov–Smirnov (K–S) test was selected to compare the discrepancy between the simulated and observed SAD patterns. The Akaike Information Criterion (AIC) test was adopted to compare the models, and the best model was indicated by the lowest AIC value. The results showed that (1) the species dispersal from the inside of Tiankeng forests to the nearby non-Tiankeng forests is limited, while species have unlimited dispersal from nearby non-Tiankeng forests to the inside of Tiankeng forests via the fringe of Tiankeng forests. (2) Species abundance, species rarity, richness, and species accumulation rate in the Tiankeng forests were significant in non-Tiankeng forests (p < 0.05), and most species in inner Tiankeng forests originated from nearby non-Tiankeng forests. (3) Based on the criterion of K-S values, all models have passed the K–S test (p > 0.05), which indicated that niche processes and neutral process worked together in the maintenance of community species diversity, the community in study area is a niche-neutral continuum. (4) Considered the lowest AIC value, the neutral (△mean AIC = 1.3) models performed better than the niche (△mean AIC = 22.7) models and statistical (△mean AIC = 2.7) in the Tiankeng forest, while the statistical models performed better than the niche and neutral models in the non-Tiankeng forests. The results suggested that the main driving force of Tiankeng forests is the neutral process. The negative terrain in Tiankeng restricted the species dispersal due to topographic constraints. However, the species dispersal from the nearby non-Tiankeng forests could promote the species succession in the inner Tiankeng. Therefore, we propose that nearby non-Tiankeng forests should be emphasized for protecting the biodiversity of Tiankeng forests.
Highlights
Understanding the mechanism for the maintenance of species diversity in communities has become an issue of ecological concern [1]
If we compare the importance value of dominant species at different sites, the dominant species in the inner area of Tiankeng forests is rarely distributed in the nearby non-Tiankeng forests, while the dominant species nearby non-Tiankeng forests is frequently distributed in the inner and the fringe of Tiankeng forest (Table 1)
Species have unlimited dispersal from nearby non-Tiankeng forests to the inside of Tiankeng forests
Summary
Understanding the mechanism for the maintenance of species diversity in communities has become an issue of ecological concern [1]. Since the 1940s, all kinds of models have been used to verify mechanistic rules to explain the structure of ecological communities, and reveal the effects of various ecological processes in SADs patterns [10,11]. There are three types of models, namely statistical, niche, and neutral Statistical models, such as Fisher’s log-series and Preston log-normal, describe the complexity of community composition using mathematics [12,13]. Niche models, such as the Broken stick and Niche preemption, focus on the connection of niche theory and SAD to infer species competition or repulsion [14,15,16]. The current research on forest communities of SAD models in negative terrain habitats is still unclear
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
