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 spec...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 lifespan. 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.展开更多
Caryota obtusa of Arecaceae is a fascinating palm tree native to southwestern China,India,Myanmar,Thailand,Laos and Vietnam.It is an economically important and threatened species and appears as a canopy dominant in so...Caryota obtusa of Arecaceae is a fascinating palm tree native to southwestern China,India,Myanmar,Thailand,Laos and Vietnam.It is an economically important and threatened species and appears as a canopy dominant in some karst areas in Yunnan.We aim to clarify the forest structure,species diversity,population status and regeneration dynamics of C.obtusa in the karst forest ecosystem of Yunnan,China.We established 56 vegetation plots dominated by C.obtusa in 10 counties of southern Yunnan.Based on the plot data,we analyzed the community stratification,floristic composition and C.obtusa’s population structure.We used questionnaires to interview local people and recorded the human activity history in C.obtusa-dominated forests.Caryota obtusa palm forests were distributed on limestone mountain slopes and gullies.There were seven forest community types.The stratification of each community included arborous layer,shrub layer and understory.The communities had rich species composition.For all the plots as a whole of each community type,Shannon–Wiener diversity index of either woody or herbaceous species ranged from 2.1 to 3.8.The diameter at breast height(DBH)-class frequency distribution of C.obtusa was a multimodal type.The regeneration was sporadic and dependent on intermediate natural disturbances.In the current population structure,a number of C.obtusa trees with small DBHs consisted mainly of the forest communities with no or a slight degree of human disturbances.Intensive human activities terribly hindered recruitment of C.obtuse,followed by the medium intensity of human activities.展开更多
基金financially supported by Ministry of Science and Technology,China (Project No.2015FY210200–15)。
文摘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 lifespan. 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.
基金support from Science and Technology Department of Yunnan University,China(2019YNU002).
文摘Caryota obtusa of Arecaceae is a fascinating palm tree native to southwestern China,India,Myanmar,Thailand,Laos and Vietnam.It is an economically important and threatened species and appears as a canopy dominant in some karst areas in Yunnan.We aim to clarify the forest structure,species diversity,population status and regeneration dynamics of C.obtusa in the karst forest ecosystem of Yunnan,China.We established 56 vegetation plots dominated by C.obtusa in 10 counties of southern Yunnan.Based on the plot data,we analyzed the community stratification,floristic composition and C.obtusa’s population structure.We used questionnaires to interview local people and recorded the human activity history in C.obtusa-dominated forests.Caryota obtusa palm forests were distributed on limestone mountain slopes and gullies.There were seven forest community types.The stratification of each community included arborous layer,shrub layer and understory.The communities had rich species composition.For all the plots as a whole of each community type,Shannon–Wiener diversity index of either woody or herbaceous species ranged from 2.1 to 3.8.The diameter at breast height(DBH)-class frequency distribution of C.obtusa was a multimodal type.The regeneration was sporadic and dependent on intermediate natural disturbances.In the current population structure,a number of C.obtusa trees with small DBHs consisted mainly of the forest communities with no or a slight degree of human disturbances.Intensive human activities terribly hindered recruitment of C.obtuse,followed by the medium intensity of human activities.
