Land use intensity determines soil properties and biomass recovery after abandonment of agricultural land in an Amazonian biodiversity hotspot

Effects of agricultural land use on soil nutrients and its variation along altitude gradients in the downstream of the Yarlung Zangbo River Basin, Tibetan Plateau

Agricultural development in alpine ecosystems can cause significant changes in soil nutrients. With large altitude spans, the combined effect of the two is still unclear in existing research. To answer this problem, this study took the downstream of the Yarlung Zangbo River Basin (YZRB) as the study area, and designed a comparative soil sampling scheme along the altitude gradient. We compared soil nutrient characteristics facility agricultural land (FA) and field cultivated land (FC), using grassland (GL), the main source of agriculture expansion, as a reference. A total of 44 sampling areas were designed within an altitude range of 800-3500 m to reveal the effects of agricultural land development along the altitude gradient on soil nutrients. Research found that the FA significantly improved soil nutrient levels, with most nutrient indicators higher than those of FC and GL (P < 0.05), while the above indicators of FC were only slightly higher than GL. Moreover, the effects of agricultural development decreased with soil depth, and mainly occurred within the 0-30 cm soil layer (P < 0.05). With increasing altitude, most of soil nutrients first decreased and then increased and differences in soil nutrients among different land use modes first expanded and then shrank. This may be related to differences in farmland management methods, vegetation coverage, and temperature under different altitude gradient constraints. Especially in middle-altitude areas, the FA not only breaks through the low-temperature limitations of the plateau, but also has the advantage of large-scale development, which is suggested for future agricultural intensification in the plateau.

Analysis of the relationship between supply-demand matching of selected ecosystem services and urban spatial governance: a case study of Suzhou, China

The mismatch between the supply and demand of ecosystem services has become a critical cause of the decline of urban ecological security. Studying the supply-demand matching of ecosystem services and exploring its association with urban spatial governance are imperative for ensuring sustainable urbanization. Taking Suzhou City as a case, the supply and demand values and matching degrees of five selected ecosystem services were assessed. Additionally, we explored the relationship between ecosystem services and urban spatial governance, with a focus on urban functional zoning. The findings indicate that first, the supply value of water production, food production, carbon sequestration, and tourism and leisure fall short of the demand value, while the supply value of air purification exceeds the demand value. The spatial matching of supply and demand shows a typical circular structure, with areas in short supply predominantly located in the downtown area and its vicinity. Second, the degree of coupling coordination between the supply-demand ratio of selected ecosystem services and the intensity of ecological control is low. Urban functional zoning can affect the supply-demand relationship of selected ecosystem services, and intensified development efforts can exacerbate the mismatch between supply and demand. Third, research on the supply-demand matching of selected ecosystem services can facilitate the assessment and regulation of urban functional zoning. Urban spatial governance can be regulated based on land use, industry, and population, with a focus on achieving a better supply-demand matching of ecosystem services. Through the analysis, this paper is aimed to provide reference for mitigating urban environmental problems and formulating sustainable urban development strategies.