Search

Relict subtropical coniferous forests in China face severe fragmentation, resulting in declining populations, and some are under significant threat from invasive alien species. Despite the crucial importance of understanding forest dynamics, knowledge gaps persist, particularly regarding the impact of invasive plants on vulnerable natives like Keteleeria evelyniana. In this study, we investigated the impact of invasive plants on the regeneration of forests dominated by K. evelyniana, a subtropical relict species in southwestern China. For this purpose, we characterized forest dynamics of 160 forest plots featuring K. evelyniana as the primary dominant species and determined whether the presence of invasive plants was correlated with regeneration of K. evelyniana. We identified four distinct forest types in which K. evelyniana was dominant. We found that radial growth of K. evelyniana trees is faster in younger age-classes today than it was for older trees at the same age. The population structure of K. evelyniana in each forest type exhibited a multimodal age-class distribution. However, three forest types lacked established saplings younger than 10 years old, a situation attributed to the dense coverage of the invasive alien Ageratina adenophora. This invasive species resulted in a reduction of understory species diversity. Additionally, our analysis uncovered a significant negative correlation in phylogenetic relatedness (net relatedness index) between native and invasive alien plant species in eastern Yunnan. This suggests closely related invasive species face heightened competition, hindering successful invasion. Taken together, our findings indicate that successful establishment and habitat restoration of K. evelyniana seedling/saplings require effective measures to control invasive plants.

The survival of relict Taxus wallichiana var. wallichiana (Yunnan yew) is threatened by overexploitation for its quality wood and medicinal properties, particularly for taxol extraction. Understanding the current status of its communities and populations is crucial for protecting existing natural forest resources. We established 53 vegetation plots in Yunnan, southwestern China, where T. wallichiana var. wallichiana is the primary dominant species. These plots were classified into four forest types. The forests were multi-stratified, with T. wallichiana var. wallichiana frequently dominating the subcanopy and shrub layer. Species diversity indices did not significantly differ among the four forest types. The age structure of T. wallichiana var. wallichiana exhibited a multi-modal pattern, with a maximum age of 1165 years. Growth was slow, with an average radial growth rate of 0.78 mm/year. Despite its strong sprouting ability, the species had a poor seedling/sapling bank and suffered from inadequate regeneration. Its seedlings/saplings are shade-intolerant. This study provides a scientific basis for effective conservation strategies, emphasizing the need for in situ regeneration to ensure the survival of T. wallichiana var. wallichiana and its contributions to biodiversity and ecosystem services.

University campuses, as small and isolated areas of rapidly growing urban areas, can provide a unique opportunity for urban biodiversity research, conservation, education, and citizen science by monitoring assemblages of butterflies within their areas. We surveyed butterfly biodiversity in a rapidly developing urban area represented by the Chenggong Campus of Yunnan University in southwestern China using the Pollard walk method. In total, 3625 butterfly individuals belonging to 50 species, 35 genera, and six families were recorded in this survey. The results showed that the families Pieridae and Nymphalidae are the families with the highest species richness on the campus, and that the family Riodinidae contained the fewest species. Pieris rapae was the most common species, and seven species assessed by the IUCN Red List were recorded. Butterfly community structure varied across habitats and seasons on campus, and butterfly diversity was higher in spring and autumn than it was in summer and winter, as well as being higher in road habitats than in scenic habitats. Unavoidable urbanisation activities (construction, green space planning, etc.) may have influenced the composition and diversity of butterflies, and conserving urban butterfly diversity requires a balance between urban planning and habitat diversity. Finally, we encourage universities and research institutions to develop butterfly monitoring platforms for citizen scientists to participate in.

Abstract Background Schima genus of Theaceae is confined to subtropics and tropics of South, East and Southeast Asia. Thirteen species of Schima are distributed in subtropical China. Many of them appear as dominant canopy species in the subtropical forests. To date, Schima species richness distribution patterns of China have remained unknown. Meanwhile, there has been a longtime debate as to whether forests dominated by Schima species are early or late successional forests. We aim to clarify Schima species richness patterns and these species’ roles in the forest succession and regeneration dynamics of the subtropical ecosystem in Yunnan Province, China. Method We mapped Schima species richness distribution patterns in China. Based on 71 vegetation plots, we analyzed forest characteristics, population structure, and regeneration dynamics of Schima species in Yunnan. Results Yunnan was found to harbor the greatest richness and the highest rarity-weighted richness of Schima species in the subtropical regions of China. We classified five primary and six secondary forest types containing Schima species as one of dominants. Yunnan had the high floristic diversity and varying stand structure of forests containing Schima species. The Schima species studied generally had a sporadic regeneration type and a long life-span. Four species (Schima argentea, Schima villosa, Schima sinensis, Schima sericans) were shade-intolerant. But three species (Schima noronhae, Schima khasiana and Schima wallichii) were considered as bi-modal type species having shade-intolerant and shade-tolerant traits. Schima noronhae was seen to be a top dominant in late successional forests, while S. wallichii was found as a top-dominant in early or middle or late successional forests. S. khasiana, Schima villosa, Schima sinensis usually appeared as a top dominant in early or middle successional secondary forests, though they also presented as a second dominant in late-successional forests. Schima argentea and Schima sericans dominated only in the early or middle/seral successional forests. Schima species’ regeneration establishment depended mainly on forest canopy gap formation through moderate human and natural disturbances. Conclusions Yunnan has high species richness and rarity-weighted richness of Schima. Both moderate human and natural disturbances have provided regeneration niches for Schima species. Some of the Schima species studied as a second dominant (rare as the top-dominant) present in the late-successional forests. Some of them are more often as the top-dominant in early or middle successional forests, where as time goes by the dominance of Schima species would be replaced by their associated dominant taxa such as Castanopsis species.

The Chinese water pine Glyptostrobus pensilis is the sole surviving species of the genus Glyptostrobus. It is endemic to southern China, central Vietnam, and eastern Laos, and today it is nearly extinct in the wild. Forest community characteristics and population structure of G. pensilis in China have remained unknown up to now. We investigated six swamp forest stands and analyzed their forest community characteristics (i.e. vertical stratification, species composition, and diversity) and population structure, including the frequency distribution of DBH (diameter at breast height) and age-classes as found in Fujian Province, southeastern China.The vertical stratifications of all the forest stands were rather simple. The remaining wild specimens ranged from roughly 15 to some 357 years for an average of ca. 85 years, with only a few individuals less than 20 years old. Compared with the stands and populations of G. pensilis in Vietnam, the taxonomic compositions of the stands in the two regions were different, except for the dominant species-G. pensilis. The Shannon–Wiener index showed the overstory of each stand had much lower diversity (0.26 on average) in Fujian Province than that (1.97 on average) in Vietnam, whereas the diversity indices were about the same (around 2.41) for the understories in the two regions. Furthermore, we discovered 18 G. pensilis seedlings at the study sites in Fujian Province. This discovery demonstrates that G. pensilis regeneration is extremely poor and its populations are declining, although these populations are relatively healthier than those in Vietnam. Keywords: Age-class, Fujian Province, Glyptostrobus, Regeneration, Relict plant, Vietnam

East Asia contains “relict” plant species that persist under narrow climatic conditions after once having wider distributions. Here, using distribution records coupled with ecological niche models, the authors identify long-term stable refugia possessing past, current and future climatic suitability favoring ancient plant lineages.

In the original version of this Article, an incorrect sample size was provided for the number of relict species (443 instead of 442) and the number of relict forests (423 instead of 422). These errors have been corrected in both the PDF and HTML versions of the Article.

Pseudotsuga sinensis, a vulnerable relict coniferous tree species, faces threats from overexploitation and habitat loss. Despite its status, the forest types, community structure, and population characteristics of this species in China have remained largely unknown. In our study, we conducted analyses of 69 vegetation plots where P. sinensis was the dominant species in southwestern China. We identified five forest types, i.e., Type 1: Pseudotsuga sinensis evergreen coniferous forest; Type 2: Pseudotsuga sinensis - Pinus yunnanensis evergreen coniferous forest; Type 3: Pseudotsuga sinensis - Cyclobalanopsis glaucoides evergreen coniferous and broad-leaved mixed forest; Type 4: Pseudotsuga sinensis - Platycarya strobilacea evergreen coniferous and deciduous broad-leaved mixed forest; Type 5: Pseudotsuga sinensis - Calocedrus macrolepis evergreen coniferous forest. These forests exhibited a multilayered vertical structure. The Simpson diversity index ranged between 0.58-0.86, while the Shannon-Wiener diversity index ranged from 1.24 to 2.3. P. sinensis trees' average growth rate of ring width decreased from 5.86 to 0.33 mm/year as increasing ages. Observed maximum age of P. sinensis was 115 years with 78 cm diameter at the breast height. Age frequency distribution of P. sinensis was multimodal. There was a great lack of individuals at 0-20 years old. Forests with moderate disturbance showed a significantly higher number of P. sinensis individuals younger than 30 years compared to areas with no, slight, or severe disturbance. P. sinensis' regeneration depends on moderate disturbance. We recommended delineating buffer zones in the protected areas at certain sites and in such zones can be allowed to sustainable firewood cutting by selectively marked species other than P. sinensis. [ABSTRACT FROM AUTHOR]