Subjects: Biology >> Botany >> Applied botany submitted time 2022-05-21 Cooperative journals: 《广西植物》
Abstract： Altitude is the key factor affecting species diversity pattern. In order to explore the altitude distribution pattern of species diversity in tropical natural forest in Diaoluo Mountain, vegetation survey was conducted in 6 tropical natural forest plots from 245 to 1 130 m. The species diversity and community characteristics of tropical natural forest along the altitude of Diaoluo Mountain were analyzed from the aspects of species composition, species diversity, flora composition and leaf characteristics. The results were as follows: (1)With the increase of altitude, the temperature decreased, the humidity increased and the human disturbance decreased. The species composition of tropical natural forest in Diaoluo Mountain and the diversity indexes of Margalef, Shannon-Wiener, Simpson, and Pielou all showed a pattern of first increase and then decrease. The middle-altitude community had the most suitable hydrothermal conditions and moderate human disturbance, so the α species diversity was the highest. (2)With the increase of altitude, the proportion of important value (IV) of dominant species decreased first and then increased, and the dominant species had obvious replacement phenomenon. The middle altitude community showed the transition nature of lowland rain forest and mountain rain forest. (3) The Sørensen community similarity coefficient between communities was significantly negatively correlated with altitude difference (P＜0.05). (4)The floristic composition was dominated by tropical elements and mainly distributed in tropical Asia (India-Malaysia). The proportion of tropical distribution was negatively correlated with altitude (P＜0.01), and the proportion of temperate distribution was positively correlated with altitude (P＜0.01). (5)The leaf characteristics showed the obvious indigenous characteristics in tropical regions mainly with mesophyll leaves, single leaves, leathery leaves and entire leaves. The proportion of microphyll leaves and single leaves was significantly positively correlated with altitude (P＜0.01), while the proportion of leathery leaves and non-entire leaves was not significantly correlated with altitude (P＞0.05). To sum up, the hydrothermal conditions and human disturbance degree of low altitude community in Diaoluo Mountain are quite different from those of high altitude community, which leads to the difference of species distribution and community characteristics, and reflects the characteristics of tropical plants adapting to their habitat conditions.
Subjects: Biology >> Botany >> Applied botany submitted time 2022-05-21 Cooperative journals: 《广西植物》
Abstract： The terrain of Hainan is high in the middle and surrounded by low terrain on all sides. From the central mountains to the eastern coastal plains, due to the difference of natural conditions and historical human interference, the composition of flora has changed. In this study, quadrant sampling and line transect survey was carried out in Huishan Nature Reserve (in the middle and north of Hainan Island) to discover its composition. Then combined with the data of Wuzhishan Nature Reserve in the middle of Hainan Island (now part of the Tropical Rainforest National Park), Baishiling Nature Reserve in the eastern noncoastal area and Tongguling Nature Reserve in the northeastern coast, which investigated by our the team, compared and analyzed their flora composition characteristics. Try to explore the relationship between the change of flora composition and the secondary, area and altitude of Nature Reserve. The results were as follows: (1) There were 1 893 species, 1415 species, 634 species, and 913 wild seed plants in Wuzhishan, Huishan, Baishiling, and Tongguling Nature Reserves, the number of species in the central protected areas was significantly higher than that in the other 2 protected areas. (2)Species similarities between protected areas were significantly correlated with differences in altitude and area (P<0.05). (3) Four protected areas were dominated by tropical elements, but at the level of genera, Wuzhishan was dominated by tropical Asia, while others were dominated pan-tropical distribution; At the level of species, distribution of tropical Asia were the most in four reserves. In conclusion, from the central mountains to the eastern coastal plains, the more secondary, the lower the altitude, the less habitat types, and the number of plant species is poorer; At the same time, at the level of genera and species, the tropical composition were increased, while temperate, endemic and relict elements were decreased.
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