Questions: Ecologists are increasingly interested in community-level consequences of biotic interactions. However, community-level studies have not considered that biotic interactions might have contrasting directions within communities, and indirect interactions are rarely quantified although they may influence community-level outcomes. We tested the hypotheses that in speciesrich plant communities from intermediate severe environmental conditions: (1) direct facilitation by dominant functional groups is balanced by negative indirect interactions among beneficiary species with no net effect at the community level on diversity and biomass, and (2) both direct and indirect interactions contribute to community composition.Location: A species-rich subalpine community of the eastern Tibet Plateau (China).
Methods:We removed dominant shrubs and graminoids and quantified, at the community and species levels, their direct and indirect effects on 43 forb species. We used multivariate analyses to assess the contribution of direct and indirect effects on community composition.Results: There were no community-level effects of either dominant life form on forb diversity and biomass. There were multiple species-level interactions that we grouped into six types based on the direction and intensity of indirect effects. We found significant relationships between species-level interactions and community composition.
Conclusions:Our study highlights that communities are sets of hidden interactions that contribute to community composition, although no interaction might be detected at the community level because hidden interactions balance each other. Future studies should assess the ecological and functional drivers of these hidden interactions.
Interacting with urban spaces that are green and blue is believed to promote mental well-being and positive emotions. Therefore, there is an incentive to strategically design urban forest landscapes in a given space to evoke more positive emotion. In this study, we conducted a pilot study in Northeast China with 24 parks from 11 cities across 3 provinces. The subjects of the study are the visitors and a total of 1145 photos and selfies were collected from open micro-twitters in Sino Weibo (~50 individuals per park). Facial expressions of happy and sad emotions were recognized and rated as percent scores by FireFACE v1.0. Demographically, male adolescents smiled more than male visitors in other age groups and female teens. Females expressed more positive emotions than males according to their positive response index (PRI; happy-sad). Multivariate linear regression indicated positive contribution of green space to happy scores (estimate of 0.0040) and a stronger negative contribution of blue area to sad scores (estimate of −0.1392). Therefore, an urban forest landscape can be optimized by mapping green- and blue-spaces to predict spatial distributions of positive emotions. Male teens are recommended more as frequent visitors than people in other age ranges.
Victory onion (Allium victorialis) is an edible vegetation that has significant value as a non-structural carbohydrate and secondary metabolite supplier. Easily measured leaf variables will be useful to predict for the flexible adjustment of physiochemical parameters in a cultural regime in plant factory conditions. Red, green, and blue light-emitting diode (LED) spectra were used to culture victory onion sprouts. Compared to the green-light spectrum, the red-light spectrum promoted leaf width and area, specific leaf area, and dry mass, water content, fine root growth, and starch accumulation in shoots, but lowered concentrations of total flavonoids and saponins. Sprouts had their shoots cut, but there were limited interactive effects with light spectra on most variables. In general, shoot-cutting depressed growth of leaf morphology, shoot weight, water content, and soluble sugar content, but enhanced accumulation of secondary metabolites. We did not find any relationship between leaf variables and secondary metabolites. Instead, wider leaves with a larger area generally had greater dry mass, water content, and soluble sugar accumulation. Leaves with deeper green colours generally had the opposite effects.
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