Study On The Relationship Between Erosion Ditch Morphology And Vegetation In Dry And Wet Seasons Of Yuanmou Dry-Hot Valley

The topography has an important influence on the growth and development of vegetation,and vegetation has an important role in ecological restoration and soil and water conservation.In the dry and hot valley region with obvious dry and wet seasons and typical erosion ditch development,the erosion ditch form has a certain relationship between topography and vegetation,which has a significant impact on the growth and development of vegetation.Therefore,the study of the relationship between the shape and vegetation of the eroded ditch in the dry and wet seasons in this area is helpful to grasp the habitat conditions and development status of the vegetation in the eroded ditch in the dry and wet seasons,so that the local ecology can be restored according to local conditions and time.The environment promotes the sustainable development of local ecology.From July 2017 to January 2019,the research team measured the shape of the eroded ditch in the study area four times in dry and wet seasons,and used the sample method to investigate the vegetation in the eroded ditch,and processed and analyzed the data to reveal correlation between erosion ditch morphology and vegetation in dry and wet seasons.The main findings are as follows:(1)After sorting and analyzing the morphological characteristics of a total of180 eroded ditches in the dry and wet seasons in the study area,it is found that:in terms of basic morphological characteristics,the elevation of the eroded ditches in the dry and wet season study areas is between 965m-1165m.The bottom slope is about 5 to 80°,the trench length is about 5 to 314m,the trench width is about 3.5to 117.5m,and the trench depth is about 2 to 47m.In general,the erosion ditch surveyed in the dry and wet seasons of the sample area is within the range of human production and life activities,so the development and morphology of the erosion ditch will have a great impact on human production and life.In addition,in the dry and wet seasons,the basic morphological differences of the eroded ditches in the study area are quite large,and the morphological forms are different and contain various morphological values that are extensive and complex,which has certain research value and difficulty.In terms of shape ratio characteristics,the maximum perimeter of the erosion ditch in the dry and wet seasons in the study area is about698m,the maximum area is about 10990m~2,the shape index values are all greater than 1,and the average value is about 1.122,indicating that the erosion range of the sample area is relatively The shape of the erosion ditch is relatively complex,and it is necessary for research and treatment.In terms of morphological ratio characteristics,the ratios of ditch length to ditch width,ditch length to ditch depth,and ditch width to ditch depth in the dry and wet seasons are all greater than 1,indicating that the eroded ditch in the sample area may be The erosion intensity in the longitudinal direction>side erosion intensity>erosion in the vertical direction,so the treatment of erosion ditch head in the sample area,slowing down the erosion ditch longitudinal erosion and undercutting erosion should be considered as a priority.(2)The research and analysis of the plant sample data collected in the sample area by the dry and wet seasons found that:in terms of the number of plant species,the plant species of the wet season of 2017 and the wet season of 2018 are better than the dry season of 2017 and 2018.The respectively annual dry season indicates that the wet season with better precipitation is more beneficial to the growth and distribution of plant species.In terms of plant numbers,the number of plants in the wet season of 2017 and the wet season of 2018 was slightly more than that of the dry season of 2017 and 2018,respectively.It also shows that the seasons with more precipitation are better for plant growth and development.In terms of plant coverage,the coverage of the 2017 wet season is slightly higher than that of the2017 dry season,but the coverage of the 2018 wet season is slightly lower than that of the 2018 dry season;the reason is that there are also sufficient,during precipitation,although the number of species in the plant has decreased through internal competition and succession.Shrubs such as the Leucaena,having good growth and development,and the plant height is high,so that the plant coverage is slightly better than the wet season of 2018.Indicating sufficient growth,the period also has a certain impact on vegetation growth and development.In terms of plant diversity,the plant richness index,Shannon Wiener index,Simpson index,and Pielou index of the wet season in 2017 are all slightly smaller than that of the dry season in 2017,but the Gleason index of plants in the wet season is much larger than that of the dry season,while 2018 The plant diversity index of the annual wet season is better than that of the dry season of 2018;the reason is that the rainfall in the wet season of 2017 is concentrated.Although the total number of plant species is large,the erosion ditch erosion may be stronger,and the plant species are more dispersed.Within a single erosion ditch,the number of the plant species and diversity is low.Because the monthly distribution of rain in the wet season in 2018is more balanced,and there is significant rainfall from May to June.The growth of vegetation is better in the wet season,but the plant diversity is better than the dry season.In general,the growth and development of vegetation in the wet season is better than that in the dry season.Rainfall and erosion of eroded ditches in the sample area have an important impact on the growth and development of vegetation.(3)Through the correlation analysis and linear regression analysis of the erosion ditch morphological features and vegetation characteristics in the dry and wet season sample area,the following conclusions are obtained:in the dry and wet season,the correlation between the erosion ditch elevation and vegetation characteristics in the sample area is the most significant.Mainly based on a significant positive correlation,indicating that the higher the elevation of the eroded ditch in the sample area,the more favorable it is to the growth of vegetation and the better habitat environment.In the dry and wet seasons,there is also a certain correlation between the slope of the eroded ditch and vegetation characteristics in the sample area,but all are mainly negatively correlated.Indicating that the greater topography of the eroded ditch,the vegetation growth and development will be more unfavorable.In the dry and wet seasons,the correlation between the length of the eroded ditch and the ratio of the ditch length to the ditch width,the ditch length to the ditch depth and the vegetation characteristics is mainly negatively correlated,indicating that the longer of the eroded ditch length or the stronger of the erosion and undercutting erosion,the more likely it is not conducive to the growth and development of vegetation.We should strengthen the management of the erosion ditch head.In the dry and wet seasons,there is also a certain correlation between the ditch width,the ratio of mouth width to mid-width,and the ratio of mouth depth to mid-depth in the sample area and vegetation characteristics.As the width of the trench increases,the topography of the eroded trench may be relatively gentle,and the plant habitat space may be larger,which is conducive to the growth and development of vegetation.The correlation between the depth of the trench,the ratio of the depth of the trench to the width of the trench and the characteristics of the vegetation differs depending on the rainfall.But in general,there is a certain correlation between the basic morphological characteristics.Shape characteristics and morphological ratio characteristics of the eroded ditch in the dry and wet season sample areas and the vegetation characteristics,and the correlation in the wet season is more significant than that in the dry season,indicating The shape of the eroded ditch in the seasonal sample area may have a greater impact on the vegetation,so the treatment and protection of the eroded ditch in the wet season should be particularly strengthened.