Residential Greenness and Long-term Mortality Among Patients Who Underwent Coronary Artery Bypass Graft Surgery

BACKGROUND

Studies have reported inverse associations between exposure to residential greenness and mortality. Greenness has also been associated with better surgical recovery. However, studies have had small sample sizes and have been restricted to clinical settings. We investigated the association between exposure to residential greenness and all-cause mortality among a cohort of cardiac patients who underwent coronary artery bypass graft (CABG) surgery.

METHODS

We studied this cohort of 3,128 CABG patients between 2004 and 2009 at seven cardiothoracic departments in Israel and followed patients until death or 1st May 2021. We collected covariate information at the time of surgery and calculated the patient-level average normalized difference vegetation index (NDVI) over the entire follow-up in a 300 m buffer from the home address. We used Cox proportional hazards regression models to estimate associations between greenness and death, adjusting for age, sex, origin, socioeconomic status, type of hospital admission, peripherality, air pollution, and distance from the sea.

RESULTS

Mean age at surgery was 63.8 ± 10.6 for men and 69.5 ± 10.0 for women. During an average of 12.1 years of follow-up (37,912 person-years), 1,442 (46%) patients died. A fully adjusted Cox proportional hazards model estimated a 7% lower risk of mortality (HR: 0.93, 95% CI = [0.85, 1.00]) per 1 interquartile range width increase (0.04) in NDVI. Results were robust to the use of different buffer sizes (100 m-1,250 m from the home) and to the use of average NDVI exposure during the first versus the last 2 years of follow-up.

CONCLUSIONS

Residential greenness was associated with lower risk of mortality in CABG patients.

An integration method to predict the impact of urban land use change on green space connectivity under different development scenarios using a case study of Nanjing, China

Urbanization leads to land use change and fragmentation of green patches, affecting natural habitats and their connectivity. Scientific prediction and analysis of the impact of future land use change on green space connectivity are an effective tool for planning and evaluating urban sustainable development, especially for ecological protection in rapidly developing areas. In this study, an integrated method is proposed that uses the CA-Markov method and combines a morphological spatial pattern analysis (MSPA) with a graph theory analysis to jointly evaluate the impact of land use change on the habitat connectivity index under different urban development scenarios from two aspects of structural and functional connectivity. Using China's rapidly developing Nanjing as the study area, the land use changes under four scenarios in 2030 are forecast, and the connectivity index is analyzed. The results showed that only under the ecological land protection scenario will forest and grassland increase, but the strong barrier effect is still brought about by urban expansion from the analysis of the structural connectivity. At the level of functional connectivity, we identified the important connecting patches and future change trends of species with different diffusion distances. In addition, we identified the key connecting patches (i.e., stepping stones) and changes and suggested giving priority to the protection of these patches. This method can be applied to other rapidly developing cities, and the conclusions can be used as a spatial explicit tool for urban green space and land use planning.

Post-fire management treatment effects on soil properties and burned area restoration in a wildland-urban interface, Haifa Fire case study

In November 2016, the urban dry streams (wadis) of the city of Haifa in Northern Israel were on fire. However, it was not just the fire that was threatening urban areas. Post-fire precipitation could turn into urban floods, further aggravating the fire damages. Several months after the fire a considerable restoration effort was initiated to restore the burned areas and mitigate future events. For urban forests the rehabilitation strategy was planned and implemented according to the topographic structure of the burned site and anticipated soil erosion. Accordingly, various post-fire management techniques were used: salvage-logging, afforestation, log erosion barriers and coconut fibre-webs. This study aimed to look at the effects of these methods on soil properties, namely, gravimetrical soil moisture, soil organic matter content, pH, electrical conductivity, hydraulic conductivity and soil water repellency. Results indicate that the control (burned, non-managed) site was the highest in soil moisture, organic matter and electrical conductivity compared to all other sites, however, the existence of ash cover made the response to precipitation unpredictable. The hydraulic conductivity (K) of the black ash (24.1 ± 8.6 mm/h), the white ash (19.0 ± 10.7 mm/h) and the disturbed (mixed) ash (11.7 ± 3.7 mm/h) were significantly higher than the underlying soil (3.3 ± 0.7 mm/h). As a result of these differences in K value, precipitation only infiltrates through the ash layers and then flows along the interface of the ash and the soil, triggering soil erosion. Most of the sites that were salvage logged showed signs of erosion. The log barriers were only effective for downstream areas. The afforestation could help to homogenise the soil, but the vegetation cover would be less dense and stable than after natural reforestation. Furthermore, the coconut fibre webs helped to improve the soil water retention and decreased the direct impact of rainfall.

Simulating urban expansion and its impact on functional connectivity in the Three Gorges Reservoir Area

Understanding the impact of urban expansion on functional connectivity is significant to biodiversity conservation. Particularly, in the Three Gorges Reservoir Area (TGRA, Southwest China), the urban land has rapidly expanded to provide settlements for an enormous population of TGRA migrants. However, the consequence of future land-use changes to the functional connectivity of the local habitat network has rarely been studied. To extend this knowledge, this paper proposes a framework that integrates a novel cellular automata (CA) simulation model and ecological network analysis, taking the TGRA as the study area, to predict how different urban expansion scenarios might affect functional connectivity for a nationally protected species, the leopard. The least-cost path modeling is used, and a set of connectivity indicators are adopted to evaluate functional connectivity. The results show that, the population-growth-based urban expansion maintains a higher connectivity than the business-as-usual and fast-urban-growth scenarios. In addition, the connectivity loss due to urban expansion can be offset by the reforestation efforts of the Green-for-Grain Project. Finally, we identify habitat patches that act as key connectivity providers, and suggest that those patches be prioritized for protection to avoid significant connectivity loss.

An ex-post evaluation approach to assess the impacts of accomplished urban structure shift on landscape connectivity

Many studies have been conducted to evaluate the effects of different urban structures on landscape connectivity, and most of them rely on the comparison approach or ex-ante scenario analysis. However, we still lack an ex-post method to capture the consequences of accomplished urban structure shift (from monocentric to polycentric), which is guided by the land use planning. To fill this gap, we develop an ex-post evaluation approach which integrates counterfactual analysis and landscape graphs. Counterfactual analysis is combined with cellular automata simulation model, to uncover what the city might look like, if it had continued to expand in a monocentric structure; and the landscape graphs enable us to reveal the possible landscape connectivity in actual and counterfactual scenarios. We select Nanjing city as the study area and 4 target species, to delve into the varying impacts of the urban structure shift on different taxonomic groups. Our case study demonstrates that: (1) the impact of urban structure shift is more relevant to the long disperser; (2) the actual landscape (polycentric) would facilitate the bird's dispersal, while (3) forest mammals have higher connectivity in the counterfactual scenario (monocentric), and the possible reasons are discussed. Finally, we demonstrate that the urban structure shift might not necessarily cause the connectivity decline, on condition that the key connectivity providers are identified by integrating ecological network analysis into the land use planning, and well preserved in the shift.