ALBERT

Description: Although the effects of gap formation resulting from thinning on microclimate, plant generation and understory plant community have been well documented, the impact of thinning on soil microbial community and related ecological functions of forests particularly in subalpine coniferous region is largely unknown. Here, the effects of thinning on soil microbial abundance and community structure using phospholipid fatty acid (PLFA) in pine plantations were investigated 6 years after thinning. The experimental treatments consisted of two distinct-sized gaps (30 m 2 or 80 m 2 in size) resulting from thinning, with closed canopy (free of thinning) as control. Soil temperature as well as the biomass of actinomycete and unspecific bacteria was sensitive to gap formation, but all these variables were only responsive to medium gap. Nonmetric multidimensional scaling confirmed that soil microbial community was responsive to gap size. In addition, gap size exerted contrasting effect on bacteria-feeding nematode and fungi-feeding nematodes. In conclusion, thinning-induced gap size would affect soil microbial community through changing soil temperature or the abundance of fungi-feeding nematodes. Soil temperature as well as the biomass of actinomycete and unspecific bacteria was sensitive to gap formation, but all these variables were only responsive to medium gap. Nonmetric multidimensional scaling confirmed that soil microbial community was responsive to gap size. In addition, gap size exerted contrasting effect on bacteria-feeding nematode and fungi-feeding nematodes. In conclusion, thinning-induced gap size would affect soil microbial community through changing soil temperature or the abundance of fungi-feeding nematodes.

Description: As it is widely accepted, cycling tends to produce health benefits and reduce air pollution. Policymakers encourage people to use bikes by improving cycling facilities as well as developing bicycle-sharing systems (BSS). It is increasingly interesting to investigate how environmental factors influence the cycling behavior of users of bicycle-sharing systems, as users of bicycle-sharing systems tend to be different from regular cyclists. Although earlier studies have examined effects of safety and convenience on the cycling behavior of regular riders, they rarely explored effects of safety and convenience on the cycling behavior of BSS riders. Therefore, in this study, we aimed to investigate how road safety, convenience, and public safety affect the cycling behavior of BSS riders by controlling for other environmental factors. Specifically, in this study, we investigated the impacts of environmental characteristics, including population density, employment density, land use mix, accessibility to point-of-interests (schools, shops, parks and gyms), road infrastructure, public transit accessibility, road safety, convenience, and public safety on the usage of BSS. Additionally, for a more accurate measure of public transit accessibility, road safety, convenience, and public safety, we used spatiotemporally varying measurements instead of spatially varying measurements, which have been widely used in earlier studies. We conducted an empirical investigation in Chicago with cycling data from a BSS called Divvy. In this study, we particularly attempted to answer the following questions: (1) how traffic accidents and congestion influence the usage of BSS; (2) how violent crime influences the usage of BSS; and (3) how public transit accessibility influences the usage of BSS. Moreover, we tried to offer implications for policies aiming to increase the usage of BSS or for the site selection of new docking stations. Empirical results demonstrate that density of bicycle lanes, public transit accessibility, and public safety influence the usage of BSS, which provides answers for our research questions. Empirical results also suggest policy implications that improving bicycle facilities and reducing the rate of violent crime rates tend to increase the usage of BSS. Moreover, some environmental factors could be considered in selecting a site for a new docking station.