Street trees assemblage is a widespread natural component in the cities and provides a wide range of ecosystem services to the cities. However, the distribution of street trees assemblage within a city is inequal. In this paper, we took air purification benefit provided by street trees for example to examine how urban form, urban geography and drivers of vegetation management affect the variation of ecosystem services provided by street trees in metropolitan Shenyang, Northeastern China. The i-Tree Street (2018) was utilizing to evaluate air purification benefit provided by street trees. We analyze the results using 2 indices: per kilometer benefit (PKB) and average tree benefit (ATB). The results showed us that (1) both indices didn’t vary along the population gradient. (2) The PKB had a decreasing trend along the urban-suburban gradient. (3) The districts which had the highest PKB and ATB are neither the old ones nor the newest one, but the districts start to develop from around 2002 and 2003. Therefore, we infer that the public policy is a main driver of vegetation management, especially for street trees, because street tree is closely related to road/street development which is closely related to economic development of a region. Besides, there could be a time lag effect for ecosystem services provided by trees.

Elucidating mechanisms underlying community assembly and biodiversity patterns is central to ecology and evolution. Genome size (GS, i.e. nuclear DNA content) determines species’ capacity to tolerate environmental stress and therefore potentially drives community assembly. However, its role in driving β-diversity (i.e., spatial variability in species composition) remains unclear. We measured GS for 161 plant species and investigated their occurrences within plant communities across 52 sites spanning a 3200-km transect in the temperate grasslands of China. Using species distribution modelling, we found that environmental factors showed larger effects on β-diversity of large-GS than that of small-GS species and that communities with abundant resources had a greater representation of large-GS species. The latter finding was confirmed following analysis of data from a 10-yr resource (water, nitrogen, and phosphorus) manipulation experiment in which resource addition resulted in increased community weighted GS based on plant biomass estimates, suggesting that large-GS species are more sensitive to environmental resource limitation and explaining the greater environmental selection on β-diversity of large-GS species. These findings highlight the roles of GS in driving community assembly and predicting species responses to global change.

Elucidating mechanisms underlying community assembly and biodiversity patterns is central to ecology and evolution. Genome size (GS, i.e. nuclear DNA content) determines species’ capacity to tolerate environmental stress or to exploit new environments and therefore potentially drive community assembly. However, its role in driving β-diversity (i.e., the site-to-site variability in species composition) remains unclear. We measured GS for 169 plant species and investigated their occurrences within plant communities across 52 sites spanning a 3200-km transect in the temperate grasslands of China. We found environmental factors showed larger effects on β-diversity of large-GS than that of small-GS species. Community weighted mean GS increased with mean annual precipitation, soil total nitrogen and phosphorus concentrations, but decreased with mean annual temperature, suggesting a negative selection against species with large GS in resources-limited or warmer climates. These findings highlight the roles for GS in driving community assembly and predicting species responses to climate change.