The purpose of this study is to explore the relationship between appearance anxiety and social media use among Chinese adolescents. Using a grounded theory approach, the study conducted two-round online interviews with ten Chinese university students and subsequently constructed a theoretical model of social media appearance anxiety among Chinese young people. The results of the study indicate that social media has a dual impact on appearance anxiety. On one hand, increased social media engagement amplifies appearance anxiety by shaping aesthetic standards and fostering comparative environments. On the other hand, diverse aesthetic perspectives and authentic presentations on social media partially alleviate appearance anxiety by promoting acceptance of unique appearances and boosting self-confidence. It is emphasized in this study that there should be an in-depth understanding of the dual impact and complicated relationship of social media on the daily lives of Chinese adolescents to further develop relevant strategies that promote healthy social media behavior among youth. Furthermore, this study calls for efforts to actively promote the healthy image and psychological well-being of adolescents while alleviating the negative impact of appearance anxiety and overall mental health. Such efforts are needed to ensure a positive and healthy development for the younger generation.

Keystone species play critical roles in ecological communities and ecosystem functions by interacting directly or indirectly with other species. Studies on keystone species will contribute to the understanding of community stability and mechanisms underlying ecosystem degradation. Based on a survey in Haizhou Bay and adjacent waters in 2011, the food web was constructed according to the predator–prey relationships of species. The binary network was analysed to calculate 11 network indices to identify keystone species, and removal analysis was conducted to examine the effects of the extinction of keystone species on the food web. Kendall rank correlation analysis showed that there were significant correlations between most pairs of the 11 network indices (P < 0.05). According to the results of principal component analysis of all these indices, several species, namely Leptochela gracilis, Loligo sp., Larimichthys polyactis, Alpheus japonicus and Oratosquilla oratoria, were identified as keystone species in the Haizhou Bay food web. Removal analysis suggested that the absence of keystone species may have considerable effects on the complexity and stability of the food web in Haizhou Bay. It is suggested that priority is given to the protection of keystone species in the marine ecosystem.

The predictive skill of species distribution models depends on the quality and quantity of input information. In addition to the physical environmental variables, prey availability is also one of the main drivers regulating spatial distribution of marine species. However, prey distribution data have rarely been considered in habitat models due to the lack of information on non-commercial prey species. This may lead to an incomplete view of species distributions and biased model predictions. In this study, we developed a new framework of two-phase generalized additive models (GAMs) based on the Tweedie distribution to incorporate the predicted prey abundance as covariates in habitat models, and applied this framework to juvenile slender lizardfish Saurida elongata in Haizhou Bay, China. This study demonstrated that the predictive skill of habitat models could be greatly improved through incorporating prey abundance as explanatory variables. The importance of prey distribution data in the habitat model confirms the essentiality of including prey data while modelling species distribution. Spatial overlap and GAM analysis demonstrated that not all dominant prey can be selected as potential explanatory variables and only those prey species showing high spatiotemporal occurrences with predators should be incorporated. The framework derived in this study could be extended to other marine organisms to improve the predictive skill of habitat models and enhance our understanding of the ecological mechanisms underlying the distribution of marine species.