Spatio-Temporal Patterns of Land-Use Changes and Conflicts between Cropland and Forest in the Mekong River Basin during 1990–2020

Abstract

The Mekong River Basin (MRB) has experienced drastic and extensive land-use and land-cover changes (LULCCs) since the 1990s, including the conflicts between cropland and forest, yet remain quantitatively uninvestigated. With three decades (1990–2020) of land-use products, here we reveal the characteristics of LULCCs and the conflicts between cropland and forest in the MRB and its three sub-basins, i.e., upstream area (UA), midstream area (MA), and downstream area (DA). The four main results are as follows: (1) Since 1990, the dominated features are forest loss and cropland expansion in the MRB and show obvious sub-basin differences. (2) The LULCC was most active before 2000, with a comprehensive dynamic degree of almost 2%. Among them, construction land has the highest single dynamic degree (5%), especially in the DA, reaching 12%. (3) The key features of land-use transfer are the interconversions of forest and cropland, as well as cropland converted into construction land. About 18% (63,940 km2) of forest was reclaimed as cropland, and 17% (45,967 km2) of cropland was returned to forest in the past 31 years. (4) The conflict between cropland and forest was the most dominant LULCC, accounting for 86% of the MRB area. Overall, cropland expansion and forest loss (CEFL) were more dominant in the DA, while cropland fallow and forest restoration (CFFR) had an advantage in the MA. Indeed, CEFL was mainly seen in the plains below a 200 m elevation level, while CFFR tended to occur in the highlands. Our basin-scale study can enrich the existing pan-regional results of LULCCs, and facilitates the understanding of the dynamics and related mechanisms of CFER and CFFR in the tropics.

Monitoring Agricultural Land Loss by Analyzing Changes in Land Use and Land Cover

“…The study of changes in land use has been widespread and beneficial for understanding the evolution of human behavior, whether it involves alterations in land use or forested areas [27,28]. These studies examined changes in the environmental system of forests and the challenges between forested land and agricultural areas.…”

Agricultural expansion and forest retreat in Mainland Southeast Asia since the late 1980s

“…Regarding the TAFF, it has witnessed various kinds of deforestation pathways and patterns of agrarian transformation (Junquera & Grêt-Regamey, 2019;Morton et al, 2006). There are differences in deforestation ways and land conversion patterns across continents, such as pasture establishment and crop intensification in the Brazilian Amazon (Garrett et al, 2018), small-scale agricultural expansion in the Congo Basin (Tyukavina et al, 2018), cropland and commercialized plantations expansion in Southeast Asia (Xiao et al, 2021;Zeng, Estes, et al, 2018), and woody encroachment in the forest-savanna transitional area of Africa (Brandt et al, 2018;Mitchard et al, 2011); therefore, previous research has greatly enriched our knowledge of FL and agricultural expansion or intensification (Feng et al, 2021;Margono et al, 2014;Stibig et al, 2014;Zhai et al, 2022). Understanding of the advance and retreat of agricultural forests in the TAFF is, however, still poor because the dynamics (including magnitudes and processes) are complex and regionally diverse, let alone the longitudinal and horizontal mechanisms and drivers (Li et al, 2021;Stibig et al, 2014).…”

Spatiotemporal characteristics and the national variations of borderland use change in Laos within the geopolinomical context

“…Recently, analyses of LUC from different perspectives have been conducted, such as an analysis of landscape patterns (Tscharntke et al, 2005), spatiotemporal variations (Zhai et al, 2022), drivers (Tian et al, 2014), mapping dynamics (Hu et al, 2021), and simulation prediction (Veldkamp and Lambin, 2001). LUC studies have mainly focused on areas with significant human activity (Han et al, 2015), fragile ecological environments (Li et al, 2013), or global impact (Deadman et al, 2004).…”

“…To determine how geopolinomical relations impact LUC in border areas, it is necessary to accurately monitor border LUC and understand its spatiotemporal processes, geographical characteristics, and national differences. To date, some studies have focused on regional scales such as provinces, watersheds, or certain cities, such as Bokeo Province in Laos (Boundeth et al, 2012) and the Mekong River Basin (Zhai et al, 2022), lacking systematic and comprehensive LUC studies in border areas (Zhang et al, 2022). Moreover, most studies focused on a single typical land type, such as the recovery of agriculture and fallow vegetation in northern Laos (Liao et al, 2015), the expansion of construction land in the Boten (Laos)-Mohan (China) border port (Li and Xiao, 2022), or the expansion of rubber plantations across national borders in Chinese border (Xiao et al, 2019).…”