| In the process of urbanization,a large number of natural mountains in the karst muti-mountainous city are surrounded by artificial matrix to form the urban remain mountains(URMs),which was the precious residual habitat resource in the built area of the muti-mountainous city areas.Under the background of urbanization,does the species diversity of URMs plants tend to be homogenized? It is not clear whether the diversity of URMs and different life types(tree,shrub,herb)plant species response relationship to the urban spatial characteristics.Based on this,the response relationship of plant species diversity of muti-mountainous URMs was explored to urban multidimensional spatial characteristics.This study takes the built-up area of a typical muti-mountainous city of Guiyang as the research area,and takes the URMs.Based on sample-plot survey,one-way analysis of variance,and least significant difference method,the diversity indices of whole and different growth types plant species of URMs composite community,and sample communities of different slope positions and slope locations were compared at two levels.Finally,by constructing the urban multidimensional spatial characteristic indicator systems,the Pearson correlation was used to reveal the response relationship of the URMs plant species diversity to the urban multidimensional spatial characteristics.The main results are as follows:(1)The rate of land use change in the study area was higher during 2010 to 2015,and the urban construction was faster.From 2015 to 2020,the rate of land use change was relatively low,and the city will move towards refined development.The land use changes in the study area 2010-2020 are mainly based on the transfer of cultivated land,URMs and the increase of construction land,urban green space and transportation land.In general,from2010 to 2020,the number and complexity of all kinds of landscape patches in the study area increased and the phenomenon of serious homogenization,the urban construction gradually developed to the internal density,the landscape structure tended to be more complex,and the landscape connectivity and spatial aggregation degree gradually decreased.(2)The quantified values of 2D patch characteristic indicators including Patch density(PD),Edge density(ED),Landscape shape index(LSI),Contagion Index(CONTAG)and Shannon diversity index(SHDI)were significantly different among different mountains.The quantitative values of PD,ED,LSI and Mean patch fractal dimension(FRAC＿MN)were consistent with the nuclear density level of construction land.There were significant differences in the Relative height(RH),Average slope(AS),Mountain size coefficient(MSC)and Mountain plane curvature(PC)of the 3D patch characteristics among mountains.2D spatial characteristic indicators PD,ED,LSI and CONTAG differ greatly in different cities surrounding mountains,while FRAC＿MN and SHDI differ less.In the urban construction area with high nuclear density,the urban 3D spatial characteristics indicators of the mountain surrounding are higher,such as Building shape coefficient(BSC),Sky open factor(SVF)and Building volume variation coefficient(CV),while the Average height(AH),Building shannon diversity index(SHDI＿B),and Floor area ratio(FAR)are lower.All the urban 3D spatial characteristics indicators of the cities around the middle nuclear density area are relatively high,while the low nuclear density area is relatively low.(3)A total of 1108 plant species were recorded in this survey,belonging to 849 genera of 308 families,among which the native plant species accounted for 63.86%,and the plant communities were obviously different in the vertical structure.The proportion of alien species in different slope directions of the mountain was the south,north,east and west,the number of alien species on different slope was mountainside,piedmont and mountain top,and the proportion of plant species and alien species of different life types were herbs,shrubs and trees.The overall plant species difference between different mountains of the mountains composite community was large,and the overall plant species diversity indices showed a significant difference between small-sized and medium-sized mountains,and no significant difference between large and small-sized and medium-sized mountains.There was no significant difference between the small-sized and medium-sized mountains herbs species diversity indices,and there were significant differences between the large-sized and small-sized,large-sized and medium-sized mountains.There was no significant difference in the diversity indices of whole,trees,shrubs and herbs between different slope directions in sample communities.There was no significant difference between the piedmont and mountainside of the mountain whole,trees,shrubs and herbs species diversity indices in different slope directions sample communities,and there are significant differences between piedmont and mountain top,mountainside and mountain top.(4)The overall plant species diversity indices of the mountain composite community has a strong response relationship to the 2D patch characteristic indicators CONTAG and SHDI,tree to PD,ED,LSI,CONTAG,SHDI,and shrub to FRAC＿MN,CONTAG,and herb to CONTAG and SHDI.The response degree of the overall plant species diversity indices in different slope direction sample communicities to the 2D patch characteristics was the south,west,north,east.The species diversity of east slope direction sample communicities tree,west and south slope direction herb has a strong response relationship to their 2D patch characteristics.The response intensity of the overall plant species diversity indices to the 2D patch characteristics of different slope direction sample communicities was mountaintop,mountainside,piedmont.The overall plant species diversity of mountain composite communities showed a significant response relationship with its 3D patch characteristics.The mountain herb species diversity indices showed a significant correlation with the 3D patch characteristic indicators DIR,LSR,RH,AS,and PC.The response strength of the mountain plant species diversity indices of different slope sample communities to its 3D patch characteristics was north,east,west,south.The response relationship of the overall plant species diversity of the mountain at different slope location sample communities to the 3D patch characteristics was mountaintop,piedmont,mountainside.(5)There was a significant response relationship between the mountain composite community overall plant diversity indices and the urban 2D spatial characteristics indicators FRAC＿MN,trees to ED,LSI,CONTAG,shrubs to PD,LSI,and herbs to FRAC＿MN.The response degree of the different slope direction sample communities of the mountain overall plant species diversity of the urban 3D spatial characteristics was the south,west,north,east.The overall plant species diversity indices on the west and south slope directions showed a significant positive correlation with FRAC＿MN and SHDI and a significant negative correlation with SHDI.The west slope direction tree and shrub,and the south slope direction shrub and herb species diversity indices are more responsive to urban 2D spatial characteristics.The overall plant species diversity indices of mountainside had a strong response relationship with PD,SHDI and FRAC＿MN,while the response relationship of tree and herb species diversity to urban 2D spatial characteristics was weak.The response intensity of the overall plant species diversity at different slope location sample communities to the urban 2D spatial characteristics was mountainside,piedmont,mountaintop.The overall plant species diversity indices of the mountain composite community showed a strong response relationship to BSC and SVF in the urban 3D spatial characteristics,while tree responded to AH,BSC,FAR,SVF,shrub to SHDI＿B,and herb to BSC and SVF.The response degree of the overall plant species diversity of the different slope direction sample communities to the urban 3D spatial characteristics was the west,south,north,east,while the different slope locations were the mountain top,mountainside,piedmont.Overall plant species diversity and AH and BSC at the piedmont,and mountainside overall plant species diversity and BSC response were strongly. |
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