晋西北黄土丘陵区土壤和地形因子对草地植被优势种功能性状的影响

Effects of soil and topographic factors on functional traits of dominant plant species in a grassland of loess hilly region,Northwest Shanxi

预测未来气候变化对生态系统功能的影响至关重要。黄土高原气候暖干化的加剧使得与此相关的环境因子对优势种功能性状的影响愈发明显。本文通过冗余分析研究了晋西北黄土丘陵区草地土壤、地形因子对9个优势种及非优势种功能性状的影响。结果显示:土壤、地形因子对优势种功能性状产生关键作用,但对非优势种功能性状影响小。土壤含水量和速效磷含量是影响优势种功能性状的关键因子,土壤含水量与优势种株高呈正相关,与相对分枝数呈负相关;土壤速效磷含量与优势种叶片氮含量、单株干重和比叶面积呈正相关,与叶片碳氮比和叶干物质含量呈负相关。海拔是影响优势种功能性状的主要地形因子,海拔与优势种叶干物质含量、相对分枝数呈正相关,与株高、叶片碳含量、叶面积呈负相关。以上结果表明,未来气候暖干化使得黄土丘陵区植物多采取资源维持型策略来适应土壤水分及养分减少的环境。

It is essential to predict the impacts of climate change on ecosystem functioning.The effects of environmental factors on the functional traits of the dominant plant species are becoming more obvious with the increasing warming and drying in the Loess Plateau.In this study,using the redundancy analysis,we examined the effects of soil and topographic factors on the functional traits of nine plant species in a grassland in the loess hilly region of Northwest Shanxi.Our results showed that soil and topographic factors played a key role in affecting the functional traits of dominant species,but did not affect that of non-dominant species.Soil water content and available phosphorus content were the key soil factors affecting the functional traits of the dominant species.Soil water content was positively correlated with the height of the dominant species but negatively correlated with the relative branch number.Soil available phosphorus content was positively correlated with leaf nitrogen content,dry weight per plant and specific leaf area of dominant species,but negatively correlated with leaf carbon/nitrogen ratio and leaf dry matter content.Altitude is the main topographical factor affecting the functional traits of dominant species.It was positively correlated with leaf dry matter content and relative branch number of dominant species,and negatively correlated with plant height,leaf carbon content,and leaf area.Our results suggest that plant species in loess hilly areas would change resource use strategies to adapt to the environment of reduced soil moisture and nutrients under future warming and drying climate.