【Objective】This study aims to investigate the carbon dynamics of subtropical mixed coniferous and broadleaved forests in Fengyang Mountain, Zhejiang Province and their response to climate change. 【Method】The Biome-BGC model was used to simulate the net primary productivity (NPP), gross primary productivity (GPP), and net ecosystem productivity (NEP) in Fengyang Mountain from 1979 to 2018, to investigate the relationships between climate factors and NPP at different time scales. Pearson correlation analysis and quadratic function fitting were performed between climate factors and NPP at different temporal scales to explore the relationship and response patterns between NPP and major climate factors, and finally, different climate scenarios were applied to predict the carbon cycling trends in Fengyang Mountain in the next 100 years. 【Result】The average values of GPP, NPP and NEP of mixed coniferous and broadleaved forests in Fengyang Mountain for 40 years were 1 392.94, 451.25 and 16.21 g/(m2·a), respectively. Except for 1984, 2002, 2005, 2008 and 2010, which were carbon sinks and showed that the sensitivity of NPP to temperature change was the highest, and the increase of temperature in summer had a positive effect on the increase of NPP, while the increase of temperature in winter had a negative effect on NPP. To a certain extent, winter rainfall showed a positive effect on NPP, while summer precipitation showed a negative effect on NPP. The gross primary productivity of Fengyang Mountain forests in RCP2.6, RCP4.5 and RCP6.0 scenarios will keep increasing in the 21st century, and by 2100, the GPP of the studied forests in Fengyang Mountain under RCP2.6, RCP4.5 and RCP6.0 scenarios will reach 1 552.73, 1 660.30 and 1 960.41 g/(m2·a), respectively, and get increased 1.38%, 8.41% and 28.00% relative to the GPP in 2018. 【Conclusion】Overall, the forest ecosystem of Fengyang Mountain exhibited carbon sinks under normal conditions, but the cloudy and rainy summer weather in the mountainous area inhibited the increasing effect of temperature on carbon sinks to some extent. The future warming, increased rainfall and higher CO2 concentration simultaneously will favor the vegetation growth of mixed coniferous forests in Fengyang Mountain.
【Objective】The study aims to establish a sound ecological compensation standard, which will provide a sustainable and stable financial guarantee for the construction of national parks. 【Method】 Taking the Qianjiangyuan-Baishanzu National Park as an example, this study calculated the upper and lower range of the national park compensation standard by comparing the difference values of provincial public welfare forests inside and outside the national park with regulating services and opportunity cost losses. 【Result】 Considering the value of forest ecosystem regulation services and opportunity cost losses comprehensively, the value of provincial public welfare forests within the national park reached 47 237.01 yuan/(hm2·a).Among them, the value of provincial public welfare forests regulating service function was 45 672.53 yuan/(hm2·a), which was 13 306.25 yuan/(hm2·a) higher than outside the scope, and the value of each regulating service was higher than that outside the implementation area. The opportunity cost loss of public welfare forests within the national park was 1 564.48 yuan/(hm2·a), which still showed a gap of 841.48 yuan/(hm2·a) compared with the current highest compensation standard of 723 yuan/(hm2·a) of the provincial public welfare forests. 【Conclusion】 At present, there was still a large gap between the ecological compensation standard implemented in Qianjiangyuan-Baisanzu National Park and that calculated based on the regulating service unit area and opportunity cost. In the future, we suggest that the compensation standard be gradually increased year by year, taking into account the actual development needs of the National Park.
【Objective】 Functional diversity is crucial for forest biodiversity protection and maintenance of ecosystem stability. Exploring the characteristics and causes of functional diversity variation at different stratum levels will assist in understanding the maintenance mechanisms of biodiversity and plant community assembly processes. 【Method】 Leaf traits and environmental factors were collected from forest plot data from an 1.6 hm2 evergreen broadleaved forest in Guangxi Yachang Orchidaceae National Natural Reserve. K-means partitioning and Gaussian kernel density estimation were used for stratification. The direct and indirect effects of species diversity and environmental factors (light, topography, and soil) on functional diversity were explored in different forest strata using structural equation models. 【Result】 The diversity indices of the understory were greater than those of the canopy (P<0.05). Species diversity had a significant direct impact on all four functional diversity indices in the understory layer, whereas only the functional richness index (FRic) and quadratic entropy (RAOQ) indices were affected directly by species diversity in the canopy layer (P<0.05). A significant indirect effect (β = 0.278, P<0.01) of canopy openness on FRic index and a direct effect (β = -0.593, P<0.01) of canopy openness on functional evenness index (FEve) were found for understory trees. Topographic factors affected canopy functional diversity. Specifically, there was a relatively significant direct effect of aspect on FEve (β = -0.420, P<0.01) and RAOQ (β = -0.300, P<0.05) indices for canopy trees. Soil factors mainly affected the functional diversity of different forest layers through species diversity. Soil total phosphorus, available phosphorus, alkaline hydrolysis nitrogen, and available potassium content had a greater effect on the functional diversity of the understory, whereas soil total potassium content affected the FRic and RAOQ indices of the canopy. 【Conclusion】 There were marked differences in the characteristics of functional diversity at different forest stratum in the study area. Functional diversity was mainly affected by species diversity, canopy openness, and soil nutrients of understory plants, whereas topographic factors determined the functional diversity of the canopy layer. This study reveals the effects of biological and abiotic environmental factors on functional diversity across different forest layers and expands the understanding of the diversity of vertical stratification. The findings provide a further reference for biodiversity protection in natural forests.
【Objective】This research aims to determine the actual threat level and prioritize the conservation of rare and endangered plants in the Wuyishan National Nature Reserve in Jiangxi Province, provide a reference for the conservation of these plants in the nature reserve.【Method】Using the line transect method combined with historical literature, the endangered coefficient, genetic value coefficient, and species value coefficient were used to quantitatively analyze the conservation priorities of 113 rare and endangered wild plants in the Wuyishan National Nature Reserve in Jiangxi Province. The relationship between the rare and endangered plants of Wuyishan in Jiangxi Province and five adjacent areas, namely Wuyishan in Fujian Province, Tianmushan in Zhejiang Province, Lushan in Jiangxi Province, Wanchaoshan in Hubei Province, and Jinfoshan in Chongqing City, were compared using the Sorensen similarity coefficient.【Result】(1) There were 113 species of rare and endangered plants in the reserve, belonging to 47 families and 85 genera. Among these, there were 6 species classified as National Class Ⅰ, 15 species as National Class Ⅱ. 20 species were classified as Jiangxi Province Class Ⅰ, 11 species as Jiangxi Province Class Ⅱ, 55 species as Jiangxi Province Class Ⅲ, and 12 species endemic to Jiangxi. (2) According to the quantitative analysis of conservation priority, 17 species (15.04%) were assessed as first class, 41 species (36.28%) as second class, 54 species (47.79%) as third class, and 1 species (0.89%) as fourth class. (3) The similarity coefficient between Wuyishan in Jiangxi Province and the five adjacent areas were about 30%. However, Wuyishan in Jiangxi Province owned more rare and endangered plants (38 species) and a higher proportion of species per unit area (0.24), indicated a higher conservation value.【Conclusion】 The excellent habitats and abundant rare and endangered plants in Wuyishan in Jiangxi Province indicate a high conservation value. The assessment and classification of the 113 rare and endangered plants more accurately reflect their current situation in the Nature Reserve, providing a reference for effective conservation plans for threatened species.
