**1. Introduction**

In the context of rapid global industrialization and urbanization, 45% of the world's population still lives in rural areas and is affected by globalization [1–3]. Meanwhile, the disparity and decline of rural development have become global issues in globalization [4,5]. Since the end of World War II, differential rural problems have gradually emerged in both developed and developing countries, with rural areas in the United States, the United Kingdom, and Canada, as well as developed countries in Europe and the United States, facing urban–rural disparities, concentrated poverty, cultural conflicts, and

**Citation:** Zhang, Y.; Li, Y.; Luo, G.; Bai, X.; Huang, J.; Tang, F.; Yu, M. Analysis of the Land Use Dynamics of Different Rural Settlement Types in the Karst Trough Valleys of Southwest China. *Land* **2022**, *11*, 1572. https://doi.org/10.3390/land11091572

Academic Editor: Xuesong Kong

Received: 11 August 2022 Accepted: 9 September 2022 Published: 14 September 2022

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irrational land use [6–8]. Developing countries, such as Africa and India, face severe land degradation, widespread poverty, food insecurity, and other problems in rural areas [9,10]. With the prominence of global rural problems, it is easy to see that rural land development and land use are among the critical issues of rural development, so it has become a human consensus to solve rural problems and explore the long-term evolution trend and sustainable development of rural areas and their land use [11].

China has always been a major agricultural country, and its villages play a vital role in ensuring its agricultural and food security and sustainable development [12]. In recent years, along with the continuous promotion of urban–rural integration and rural revitalization strategy, rural-related research topics have gradually become a major socioeconomic issue of concern to researchers and the Chinese government [13]. As one of the carriers of rural society, village settlements are widely used in rural studies [14]. A rural settlement is a production and living place formed by the interaction of rural residents with the surrounding natural environment, socio-economic environment, and cultural environment [15]. The integrated development and optimal spatial reorganization of all elements of rural settlements have become an academic hotspot driven by the urgent need and strategy for the sustainable development of national rural society [16].

Rural settlements are the basic spatial units of rural geography and an important part of the study of human–land relations [17]. Academics have conducted many studies on rural settlements, rural settlement land use, and rural settlement development and have achieved remarkable results. In studying the evolution of rural settlements, scholars initially focused on the formation and orientation of rural settlements [18,19]. With the development of geographic information technology, scholars have paid more attention to the types of rural settlements [20], spatial distribution, scale [21–24], density [25,26], driving mechanisms [27], transformational development, spatial reconfiguration, etc. [28,29]. In the studies related to land use change in rural settlements, scholars have focused on national [30,31], provincial [32], regional [25,33,34], and basin [35,36] scales of study, and used research methods such as the landscape pattern index method [37], neighborhood buffer analysis [38], spatial autocorrelation analysis [39], and sample zone analysis [40] to explore the core issues [41,42] of the spatial layout of rural settlement land use, driving mechanisms of land use evolution, and spatial optimization and reorganization. In the study of rural settlement development, scholars have devoted themselves to the study of rural settlement development types and patterns [12,17,43], development potential [44], multifunctionality [13,45,46], and sustainable development [47,48]. Several studies have analyzed rural settlements, land use, and rural settlement development separately. However, previous studies have only observed single-factor dynamic changes in rural settlements. There is a lack of in-depth research on the comprehensive development types of different rural settlements, the evolution of settlement development, and surrounding land use elements and there is still a lack of research on the dynamic changes in land use at the microscopic scale of rural settlements in long time series. Few studies have examined the integrated perspective of human–land interaction and rural development. The inadequacy of these studies make it difficult for us to accurately judge and grasp the regularity and stages of the evolution process of rural settlements and to scientifically optimize the planning related to rural settlements in rural revitalization. Therefore, it is necessary to study the dynamic changes in land use in rural settlements on a microscopic scale.

The karst trough valley is one of the typical karst landform types in China, as it is a large area with a flat topography at the bottom of the trough. The region is characterized by high population pressure, low land carrying capacity, relatively lagging socio-economics, considerable topographic relief, and significant differences in spatial patterns of land use. Based on this, clarification of the "people (settlement)—land (land use) relationship and its evolution" in the trough valley is vital for the territory. In the context of the current dualistic development of urban–rural territorial systems, the number, scale, and pattern of land use in and around different rural settlement types in the trough valley varies, and the differences in land use evolution of different rural settlement types reflect the differences

in regional rural socio-economic development. Because of this, to explore the land use evolution pattern at the settlement scale in the karst trough valley, this study grasps the "type" of settlement with the help of "typical" settlements. The study uses "micro-scale long time series" to map "large scale short time series." The study selects different types of settlements in karst troughs and valleys as research objects and explores the spatial and temporal evolution characteristics of land use around different types of settlements on the settlement scale. At the same time, we analyze the land use transfer trajectories of different types of settlements; explore the land use rise and shrinkage patterns; and reveal the interactive feedback mechanisms of land use change (LUCC), land use transformation (LUT), and rural settlement transformation (RST) processes. We aim to explore the driving factors of the spatial differentiation of rural areas to provide a more scientific and reasonable reference basis for the land use of rural settlements under different geomorphological conditions in other karst trough and valley areas, to achieve a balance between the supply and demand of land use in rural settlements in karst troughs and valleys, to promote sustainable rural socio-economic development and ecological–environmental protection, and to provide a reference for enriching the research framework and typical cases of rural land use evolution and land use transformation in China.

Accordingly, we proposed the following research question: What is the development type of rural settlements in the karst trough valley of Southwest China? How does land use change across rural settlement types on the buffer scale? What natural or socioeconomic factors influence land use change in rural settlements? Specifically, we tested two main hypotheses: (1) Land use change in rural settlements is driven by natural and socio-economic factors. (2) In the karst trough valley area of Southwest China, there is an interactive feedback mechanism of land use change–land use transformation–rural transformation development. To test these hypotheses, we selected the karst trough valley area in Southwest China as the study area. In Section 1, we briefly describe the study area and data sources. In Section 2, we list the appropriate research methods and the selection of typical clusters. Section 3 analyzes the results of different rural settlement types, land use buffer changes, land use transfer trajectories, and land use coupling states in karst trough valleys. In Section 4, we analyze the drivers of land use change and feedback mechanisms for different settlement types and highlight our research uncertainties and future research directions. Finally, the conclusions of our study are presented in Section 5.

#### **2. Study Area and Data Sources**
