Yuling Qiu

The degradation of urban ecology, particularly in metropolitan areas distinguished by dense populations and impervious surfaces, presents a worldwide challenge linked to swift urban expansion. Despite extensive documentation of urbanization’s impact on broad regions or specific urban ecosystems over defined time periods, there remains a scarcity of studies investigating the spatiotemporal dynamics of landscape pattern (LP) changes in specific ecosystems at small-to-medium scales within inland megacities as a response to urbanization. Therefore, this work focused on the Bailuwan Wetland Park (BWP) in Chengdu, an inland megacity in southwestern China. Employing satellite imagery data from selected years spanning the previous decade (2010–2021, encompassing 2010, 2012, 2015, 2018, and 2021), this investigation delved into the influences of urbanization on the LP over various time-frames and across different land use/land cover (LULC) types. Our study revealed that urbanization has a significant impact on the patch-/landscape-level characteristics, including the class area (CA), number of patches (NP), patch density (PD), percentage of landscape (PLAND), aggregation index (AI), contagion index (CONTAG), largest patch index (LPI), landscape shape index (LSI), fractal dimension index (FRAC_MN), Shannon’s diversity (SHDI), and evenness index (SHEI). Over the period from 2010 to 2021, NP and PD experienced notable increases, while landscape shape (LSI/FRAC_MN) exhibited greater complexity and fragmentation (PLAND) intensified. Further, landscape heterogeneity (AI/CONTAG) and diversity (SHDI/SHEI) decreased. Particularly significant was the conversion of 52 ha of agricultural land to vegetation, resulting in heightened complexity and fragmentation in vegetation patterns. Additionally, the CA of lakes and rivers decreased following the establishment of the park, while the CA and NP of bare land presented significant increases. These findings suggest that rapid urbanization significantly influences the spatial–temporal dynamics of wetland landscape patterns. Consequently, it is imperative for society to prioritize the restoration and protection of urban constructed wetlands.

Inland lake water–air interfaces, particularly the partial pressure of CO₂ (pCO₂), have become key parameters in the study of global carbon cycle changes. However, there are few studies on short-term daily variations in pCO₂ in urbanizing lakes. The fluctuations in pCO₂ and CO₂ fluxes (fCO₂) were monitored biweekly on-site for pCO₂ assessments during daytime hours (7:00–17:00 CST) from January to September 2020 in an urbanizing lake located in Southwest China. We found a pronounced and uninterrupted decline in the average levels of pCO₂ and fCO₂ from 7:00 to 17:00 CST. Notably, the mornings (7:00–12:00 CST) exhibited substantially elevated pCO₂ and fCO₂ values compared to the afternoons. Specifically, compared to 7:00, the mean pCO₂ and fCO₂ at 17:00 CST decreased by ca. 74% and 112%, respectively. The average daytime pCO₂ was 707 ± 642 μatm, significantly higher than the typical atmospheric CO₂ levels of 380–420 μatm, while the average pCO₂ on 9 January, 1 April, and 27 July was lower than typical atmospheric CO₂. Each month, all water environmental parameters showed significant differences. pCO₂ and fCO₂ reached maximums in September; water temperature and turbidity significantly increased; and pH, dissolved oxygen and transparency markedly decreased. Additionally, the correlation between pCO₂ and environmental factors demonstrated that the nutrient levels, dissolved oxygen, pH, and transparency/turbidity had significant roles in CO₂ dynamics in this lake. Therefore, this urbanizing lake could serve as a CO₂ source and sink during the daytime.

Wetlands are often referred to as the Earth’s kidneys. However, wetlands worldwide are still negatively affected due to a lack of comprehensive understanding of wetland landscape ecological health (WLEH). Based on this background, we analyzed and compared the conceptual definitions, research progress, contents (in terms of structural, functional, and process health), and methods (indicator species approach, ecological integrity assessment, conceptual model evaluation including the vigor–organization–resilience (VOR), pressure–state–response (PSR), and ecological feature–function–socioeconomic (EFFS) models, and water–gas CO₂ calculation) over the past 20 years (2000–2022). Moreover, the concept definition and research progress of ecosystem health (EH) and landscape ecological health (LEH) and WLEH research outlook were analyzed. In this study, it was shown that WLEH could be considered a LEH subset, while the LEH is a specific EH perspective. These three concepts share a common focus on ecosystem conditions, functions, and services while considering ecological processes and habitat characteristics. However, they differ in the scope and specific types of ecosystems considered. This review may provide references for ecological conservation and restoration of artificial and restored wetland landscapes.