Aims It is important to explore the underlying mechanisms that cause triphasic species–area relationship(triphasic SAR)across different scales in order to understand the spatial patterns of biodiversity.Methods Inste...Aims It is important to explore the underlying mechanisms that cause triphasic species–area relationship(triphasic SAR)across different scales in order to understand the spatial patterns of biodiversity.Methods Instead of theory establishment or field data derivation,I adopted a data simulation method that used the power function of SAR to fit log-normal distribution of species abundance.Important Findings The results showed that one-step sampling caused biphasic SAR and n-step sampling could cause 2n-phasic SAR.Practical two-step sampling produced triphasic SAR due to the Preston and Pan effects in large areas.Furthermore,before exploring biological or ecological mechanisms for the nature phenomenon,we should identify or exclude potential mathematical,statistical or sampling reasons.展开更多
We studied the mathematical relations between species abundance distributions （SADs） and species-area relationships （SARs） and found that a power-law SAR can be generally derived from a power-law SAD without a spe...We studied the mathematical relations between species abundance distributions （SADs） and species-area relationships （SARs） and found that a power-law SAR can be generally derived from a power-law SAD without a special assumption such as the ＂canonical hypothesis＂. In the present analysis, an SAR-exponent is obtained as a function of an SAD-exponent for a finite number of species. We also studied the inverse problem, from SARs to SADs, and found that a power-SAD can be derived from a power-SAR under the condition that the functional form of the corresponding SAD is invariant for changes in the number of species. We also discuss general relationships among lognormal SADs, the broken-stick model （exponential SADs）, linear SARs and logarithmic SARs. These results suggest the existence of a common mechanism for SADs and SARs, which could prove a useful tool for theoretical and experimental studies on biodiversity and species coexistence.展开更多
Natural karst forests can support very high level of biodiversity, but difference of species diversity between the natural karst forests and non-karst forests is still less concerned. To analyze the difference of spec...Natural karst forests can support very high level of biodiversity, but difference of species diversity between the natural karst forests and non-karst forests is still less concerned. To analyze the difference of species diversity of the natural karst forests and non-karst forests in subtropics, we made a census of all woody species with diameter at breast height （dbh） 〉 1 cm in a 1-ha plot in Mulun subtropical karst forests and a 1-ha plot in Maoershan subtropical non-karst forests, Guangxi of south-western China. Species richness in Mulun plot （120 species） was higher than that in Maoershan plot （116 species）. Mulun plot contained more families and genera, more stems and a larger proportion of rare species （species of individuals less than or equal to 1 ha^-1）. At smaller scale （〈4000 m^2）, species accumulation rate in Mulun plot was lower than that in Maoershan plot, and it was reversed at larger scale （〉5000 m^2）. Total basal area in Mulun plot （18.47 m2） was smaller than that in Maoershan plot （30.74 m^2）. Size structure distribution of all woody species in the two plots showed insignificant difference. The ten most dominant species, families and genera were quite different in the two plots. In Muiun plot, the most important species and family were Sinosideroxylon wightianum and Sapindaceae, while in Maoershan plot, Castanopsis carlesii and Fagaceae were the most important species and family. All these results suggest that middle subtropical natural karst forest in Mulun supports diverse species with high spatial variability, and their species composition are quite different with non-karst forests. This study implies that special attention is needed on selecting suitable species in karst forest restoration and vegetation management strategies.展开更多
基金The work was supported by the National Key R&D Program of China(2018YFF0214905 and 2016YFC1200802).
文摘Aims It is important to explore the underlying mechanisms that cause triphasic species–area relationship(triphasic SAR)across different scales in order to understand the spatial patterns of biodiversity.Methods Instead of theory establishment or field data derivation,I adopted a data simulation method that used the power function of SAR to fit log-normal distribution of species abundance.Important Findings The results showed that one-step sampling caused biphasic SAR and n-step sampling could cause 2n-phasic SAR.Practical two-step sampling produced triphasic SAR due to the Preston and Pan effects in large areas.Furthermore,before exploring biological or ecological mechanisms for the nature phenomenon,we should identify or exclude potential mathematical,statistical or sampling reasons.
文摘We studied the mathematical relations between species abundance distributions （SADs） and species-area relationships （SARs） and found that a power-law SAR can be generally derived from a power-law SAD without a special assumption such as the ＂canonical hypothesis＂. In the present analysis, an SAR-exponent is obtained as a function of an SAD-exponent for a finite number of species. We also studied the inverse problem, from SARs to SADs, and found that a power-SAD can be derived from a power-SAR under the condition that the functional form of the corresponding SAD is invariant for changes in the number of species. We also discuss general relationships among lognormal SADs, the broken-stick model （exponential SADs）, linear SARs and logarithmic SARs. These results suggest the existence of a common mechanism for SADs and SARs, which could prove a useful tool for theoretical and experimental studies on biodiversity and species coexistence.
基金the National Key Technologies R&D Program of China(2011BAC09B02,2012BAC16B01)National Natural Science Foundation of China(No.31300359)Guangxi Science and Technology Project(1355007-3)
文摘Natural karst forests can support very high level of biodiversity, but difference of species diversity between the natural karst forests and non-karst forests is still less concerned. To analyze the difference of species diversity of the natural karst forests and non-karst forests in subtropics, we made a census of all woody species with diameter at breast height （dbh） 〉 1 cm in a 1-ha plot in Mulun subtropical karst forests and a 1-ha plot in Maoershan subtropical non-karst forests, Guangxi of south-western China. Species richness in Mulun plot （120 species） was higher than that in Maoershan plot （116 species）. Mulun plot contained more families and genera, more stems and a larger proportion of rare species （species of individuals less than or equal to 1 ha^-1）. At smaller scale （〈4000 m^2）, species accumulation rate in Mulun plot was lower than that in Maoershan plot, and it was reversed at larger scale （〉5000 m^2）. Total basal area in Mulun plot （18.47 m2） was smaller than that in Maoershan plot （30.74 m^2）. Size structure distribution of all woody species in the two plots showed insignificant difference. The ten most dominant species, families and genera were quite different in the two plots. In Muiun plot, the most important species and family were Sinosideroxylon wightianum and Sapindaceae, while in Maoershan plot, Castanopsis carlesii and Fagaceae were the most important species and family. All these results suggest that middle subtropical natural karst forest in Mulun supports diverse species with high spatial variability, and their species composition are quite different with non-karst forests. This study implies that special attention is needed on selecting suitable species in karst forest restoration and vegetation management strategies.
