| The study of distribution pattern and environmental response of plant functional traits have long been important in functional ecology.We can better understand the driving mechanism of the environment to the changes of plant distribution pattern,and provide the theoretical basis to predict the future trend of vegetation development through the studies on the relationships between plant functional traits and environmental factors.China is one of the countries which have the most abundant species in the northern hemisphere.As representative groups,distribution pattern and the survival status of endemic species are more worthy of attention.Endemic species has commonly been regarded as an important criterion for biodiversity conservation at the global scale and even at the national scale.However,the comprehensive collection of field data is faced with enormous challenges,in which limited resources make it difficult to study the functional diversity of all species in such a large country.Based on this,we chose Chinese endemic woody seed plants as the research object.We selected two important functional traits(plant height and flowering)from plant vegetative traits and regenerative traits,to analysis their distribution pattern changes,and to explore the key environmental factors combined with climate,space and soil factors,which affect these changes,by using spatial analysis,Pearson correlation analysis,a correlation analysis and model selection analysis and multi-model inference based on AIC,RDA analysis,and variance decomposition.The conclusions were as follows:(1)Height of Chinese endemic woody seed plants were most in 1-15 m,the overall distribution showed an increasing trend from northwest to southeast: height of temperate plants < plant height of subtropical plants < plant height of tropical plants.The plant height was the most widely distributed in the area of 6-10 m,and the plant height of 11-15 m was significantly distributed in the southeast by the embedded ways.The distribution of plant height above 15 m was narrow and scattered,without obvious regularity.(2)The spatial distribution of flowering of Chinese endemic woody seed plants showed obvious horizontal zonality.The first flowering date showed a decreasing trend from northwest to southeast,while the last flowering date and flowering duration increased from northwest to southeast.The flowering showed obvious seasonal changes.Most of plants flowered in spring and summer with single-peak distribution.(3)The flowering pattern of different leaf habits species was consistent with the overall pattern of Chinese endemic woody seed plants,which was also belonged to mass-flowering pattern in spring and summer.The flowering time of the evergreen species was one month earlier than that of the deciduous species,while the deciduous species were more seasonal.(4)There was significant correlation between plant height and flowering in distribution of Chinese endemic woody seed plants,that was,higher trees tended to bloom early as a whole.In 1-10 m,higher trees tended to bloom earlier,while above 10 m,higher trees tended to bloom later.The plant height in 1-5m had the strongest correlation with the first flowering date,and the plant height in 21-50 m had the strongest correlation with the last flowering date and flowering duration.(5)Plant height was positively correlated with temperature,precipitation and longitude,while negatively correlated with latitude,altitude and soil pH.The main factors that affected plant height were the mean temperature of the warmest quarter,annual mean temperature,temperature seasonality and altitude.Climate was the core influencing factor of plant height.Temperature was the key driving factor for the variation of plant height of endemic woody seed plants in China.(6)Climate had the greatest influence on flowering of Chinese endemic woody seed plants,and the temperature(temperature seasonality and min temperature of the coldest month)was the key factor.The combined effects of climate and space also played an important role in flowering.Evergreen plants were more sensitive to environmental changes than deciduous plants.Precipitation was the main factor which affected the flowering of evergreen plants,while the main influencing factor of flowering of deciduous plants is temperature. |
