The high-resolution regional division of mountainous area types has important scientific significance for promoting precise management of land space and regional sustainable development. At present, the classification method of mountainous area types is mainly at the county level and above, while classifications for towns and villages are nearly nonexistent, which poses a technical challenge for rural revitalization and the construction of ecological civilization in mountainous areas. We used Yuxi city, Yunnan Province, as the target area of this research, which was based on GIS technology and Digital Elevation Model (DEM) data and socioeconomic environmental monitoring data. The most appropriate statistical unit (e.g., 2.8224 km2) for topographic relief was defined, and the study area was divided into six mountain types: flatlands, hills, low mountains, medium-low mountains, midmountains, and subhigh mountains. Based on the township scale, an index system and classification method dominated by the plain comprehensive index were established to carry out mountain area classifications at township scales. The 75 towns of Yuxi city can be classified into 27 plain towns, 23 mountain-plain towns, and 25 mountain towns from an empirical application perspective, which can provide strong data support and a reference basis for studying the evolution characteristics of land use in different geographical spaces and their interrelationships as well as differentiated land space planning and governance.

The purpose of this study was to explore the correlations between land use/cover change and cultivated land ecological security in flatland and mountainous areas. Firstly, the spatiotemporal variation characteristics of land use/cover change are described in conjunction with ArcGIS10.5 software based on remote sensing images of 2005 and 2015. Then, by establishing a pressure-support framework as an assessment indicator system and developing an improved BP neural network model via a genetic algorithm with the help of MATLAB2016a, the spatiotemporal dynamic changes of cultivated land ecological security in Yuxi City from 2005 to 2015 are evaluated. The results showed that the transformation of farmland area accounted for a large proportion of increased constructive land and land use/cover spatial variations were significantly different among counties, which manifested the changes in farmland and the construction land in flatland areas but also facilitated a mutual transformation of forest and grass in mountainous areas. Moreover, ecological security status presented a clear difference among counties due to their different land use/cover changes. The ecological security state of the flatland expressed a higher ecological pressure and lower ecological support, so the security grade was IV. Otherwise, the ecological security was superior and the security grade was level II or I in the mountainous areas. Thus, protection strategies for ecological security should be differentiated in the flatland areas and mountainous areas due to their different ecological security status brought by land use/cover change.

In this paper, a fractional-order land model with Holling-II type transformation rate and time delay is investigated. First of all, the variable-order fractional derivative is defined in the Caputo type. Second, by applying time delay as the bifurcation parameter, some criteria to determine the stability and Hopf bifurcation of the model are presented. It turns out that the time delay can drive the model to be oscillatory, even when its steady state is stable. Finally, one numerical example is proposed to justify the validity of theoretical analysis. These results may provide insights to the development of a reasonable strategy to control land-use change.

This study examined topographic influence on spatial and temporal variability in the normalized difference vegetation index (NDVI) derived from the Satellite Pour l'Observation de la Terre-Vegetation at the regional and landscape scales in the Jiaodong Peninsula. The generalized additive models were used to quantify the spatial variation of NDVI attributable to local terrain and topographically related variables including altitude, exposure to incoming solar radiation, topographic wetness index, distance to the nearest stream and distance from the coast. NDVI distribution shows significant dependence on topography. The variables explained 38.3 % of variance in NDVI at the peninsula, and 30-45.3 % of variance in NDVI at the woodland, cropland, and grassland landscapes. At the Jiaodong Peninsula scale, NDVI is influenced primarily by distance from the coast. However, topographic wetness index has the most explanatory power for NDVI at the woodland, cropland, and grassland landscapes. Through a statistical nonparametric correlation analysis (Spearman's r), the study indicates that spatial distribution of NDVI changes during the period 1998-2009 and future change trend of persistence determined by Hurst exponent is closely associated with topography and topography-based attribution. These results highlight the importance of topographic changes at landscape and regional scales as an important control factor on NDVI patterns.

Markov chain is one of the most widely used methods for land use change forecasting, however, it's a nonspatial model and few papers have discussed the effects of timeduration on its performance. In this paper, we first present the primary methodologies of the Spatial-Markov model, which endows the ordinary Markov chain with spatial dimension using spatial analysis techniques, and then explore the effects of forecasting time-duration on the model's performance. By taking Shandong province, China as a case study area, land use maps in 1990, 1995, 2000, 2005 and 2010 were created using on Landsat images and then the Spatial-Markov model was developed at 1 km spatial scale. In detail, we repeatedly run the model by choosing different initial time points and the same time step (five year interval) to simulate the spatial-temporal dynamics of land use change from 1990 to 2010. The forecasting results of a single run included a stack of ratio scale images and a derived nominal scale image, χ 2 test and Kappa coefficient were adopted to evaluate their accuracy respectively. It turned out that the Spatial-Markov model could achieve very good performance for short period forecasting. For the case study, it was quite qualified for the prediction of three time steps (up to 15 years) or more within which the results had much high reliability, however, time-duration of forecasting had much significant impact on the model's performance, the longer the forecasting duration, the lower the model's accuracy.

Taking Yuxi City, a typical mountain-flatland in the southwestern karst mountainous area, as an example, we used six remote sensing images from 1995 to 2018 as the main data sources, and the grid scale was used to calculate the landscape pattern index in order to analyze the temporal-spatial evolution characteristics of the landscape pattern. The results are shown as follows: (1) At the class level, most landscape indices and fragmentation degrees of landscape units in the flatland area are significantly higher than those in the mountainous area. The layout of construction land and cultivated land is also more concentrated than that in the mountainous area, but the central tendency of forest and grass in the mountainous area is more eye-catching. (2) At the landscape level, although the landscape diversity index and landscape shape index of both the mountainous areas and the flatland areas decrease in the low-value area and increase in the high-value area, the proportion of high-value areas in the flatland area is noticeably greater. The proportion of the high-value areas of the largest patch index in the mountainous area is significantly greater, and in the flatland area, the low-value area continues to expand while the middle and high value areas continue to shrink. (3) The landscape shape of the flatland area is becoming more complex, and the landscape units in the mountainous area tend to be single. The natural landscape of forest and grass in the mountainous area continues to expand and tends to be contiguous, while the man-made landscape in the flatland area continually increases and shows fragmentation, reflecting the pattern characteristics formed by the coupling evolution of land use between two regions. The urban expansion and the increase in the construction land in the flatland area are mutually causal with the decrease in cultivated land and the increase in forest and grass in the mountainous area.

Land use/land cover change is an important carrier for the study of human-land relationship. Yuxi City is a typical area of with alternating mountain and basin landforms, forming a special human-land system with “mountains” and “basins” as the core elements. Taking 75 towns in Yuxi City, Yunnan Province as a case study, this paper uses a comprehensive evaluation model of land use/land cover change and related analysis methods to analyze the changes of land use pattern in mountainous areas and basin areas respectively from 1995 to 2018, and to reveal their spatial differences and its influencing factors. The results show that: 1) The dynamic evolution of land use in the mountainous area and the basin area presented obvious stage characteristics. From 1995 to 2005, the average comprehensive dynamic degree of land use in the mountainous area was 1.7861, which was significantly higher than the 1.7033 in the basin area. The average comprehensive dynamic degree of land use in mountainous areas from 2005 to 2018 was 1.1284, which was significantly lower than 1.9427 in the basin area. 2) From 1995 to 2018, the land use degree and the comprehensive dynamic degree of land use continued to rise in the basin area, while the mountainous area showed a trend of rising first and then falling. The overall change trend of land use depletion in the mountainous area was consistent with that in the basin area, but the mountainous area was always higher than that in the basin area. 3) The land use change in mountainous areas and basin areas was mainly reflected in the difference of natural factors and socio-economic fators. The radiation and agglomeration functions of the basin area have always attracted people to migrate from the mountains to the basin, which was beneficial to the ecological restoration of the vegetation in the mountains. Since the mountainous area and the basin area are geographically adjacent, the coupling and coordination of the two is the premise and foundation for the sustainable development of the region. This causal relationship of land use changes provides a reliable basis for the regulation of mountain-basin human-land coupling relationship.

As an important part of urban public infrastructure, urban green space plays an indispensable role in urban development and public physical, mental, and emotional health. By collecting open data such as POI, OSM, and ASTER GDEM and using spatial analysis software such as ARCGIS, QGIS, and Global Mapper, this study conducted thermal analysis of crowd activities, service pressure analysis, and demand evaluation for the layout of park green space in the central urban area of Yuxi City. The results show that there are great differences in the area and spatial layout of the thermal classes of crowd activity. Class II occupies the largest area, accounting for 60.73%, while class V occupies the least area, accounting for 2.04%. The thermal classes of crowd activity decrease from the center of the city to the periphery, and their area increases with the decrease of the thermal classes. With the increase in the level of green space service pressure, the proportion of the area decreased, among which the proportion of grade I was as high as 53.20%, while that of grade V was only 1.89%, which was mainly affected by the spatial location. The demand level and the area of park green space are obviously different, mainly concentrated in the first level, accounting for 69.68% of the total demand, and the large area is scattered in the periphery of the central urban area, followed by the fourth level, accounting for 10.46%. The area of other levels, especially the high level of demand, is less. Comprehensive analysis shows that the service level, type of green space, service pressure, and demand of green space have a strong correlation with the geographical location. In future planning, Yuxi City should combine the population distribution density and land development intensity and carry out reasonable layout and planning of park green space by reducing the low-demand area, increasing the green space area of high-demand area, improving public transportation, and improving accessibility.