Effects Of Topography On Plant Diversity Patterns In Alpine Meadow Using Multi-scaleAnalysis

Studying the impact of topography on plant diversity is one of the hot spots of ecology and geography research.However,most studies are carried out on a scale or level,which limits the overall and systematic understanding of the effects of topography on plant diversity.Alpine meadows are widely distributed in the eastern and celtral parts of the Qinghai-Tibet Plateau.They are not only the material basis for animal husbandry production and living,but also have various ecological functions such as water conservation,biodiversity conservation,soil and water conservation,and species gene banks,et al.Taking Hezuo,a plateau city in the eastern part of the Qinghai-Tibet Plateau,as an example,using remote sensing images,digital elevation models,land use planning maps,field survey data and yearbooks,etc.,with the support of remote sensing and GIS technology.Complemented by software such as landscape analysis,ecological data processing and statistical analysis.On the three levels of landscape,ecosystem and species,we analyzed the impacts of topography on the diversity pattern of alpine meadows.The main conclusions are as follows:1.We found that the characteristic scale of the landscape and ecosystem is 1400 m and 1000 m,respectively.Our findings are different from those of GAO Yan-fang,XUE Dong-dong,and JIANG Chong-ya,reflecting the regional characteristics of the alpine meadows in the study area.2.Topographic factors have significant impacts on plant diversity at three scales.However,the effects of topographical factors on plant diversity differ in three scales.Among them,species diversity is most affected by topographic factors,landscape diversity is less affected,and ecosystem diversity is the least.The importance of topographic factors on plant diversity at three scales is mainly as follows:at the landscape scale,slope and altitude is the most important factor,followed by slope;At the ecosystem scale,altitude is the dominant topographic factor of diversity change;at the species scale,slope is the most important factor affecting species diversity.In general,altitude and slope are the main topographic factors affecting plant diversity in alpine meadow,while slope has a weak impact on plant diversity at all levels in alpine meadow.3.The correlation between topographic factors and plant diversity showed a certain regularity on three levels of scale.The elevation factor and plant diversity index showed a significant negative correlation on the landscape scale and species scale,respectively,but showed a significant positive correlation on the ecosystem scale.The relationship between slope factor and plant diversity showed a significant positive correlation on the landscape scale but showed a significant negative correlation at the species scale.On the ecosystem scale,the slope factor is only significantly negatively correlated with the richness index.The relationship between the slope aspect and plant diversity showed a weak correlation both on the landscape scale and the ecosystem scale,while showed a significant negative correlation on the species scale.The relationship between topographical humidity index factor and plant diversity showed a significant negative correlation at the landscape scale,but a significant positive correlation on the species scale.On the ecosystem scale,the topographical moisture index is only significantly positively correlated with the richness index.Our findings not only provide a typical case for multi-scale research on the effects of topography on plant diversity,but also provide a scientific basis for the sustainable development of alpine meadows.