Previous cultural evolutionary analyses have used neutral models as null models to distinguish between the unbiased copying and the biased transmission of cultural traits. Here, we define economic and ecological concepts as cultural traits that constitute a complex system representing sustainability ideas. We analyse the frequency distribution, turnover and innovation rates of 3,713 concepts appearing in China’s mainstream newspaper, People’s Daily, from 1946 to 2015. Results reveal that (1) economic concepts show a stronger tendency towards random copying than ecological concepts; (2) popular economic ideas experience anti-conformist bias, while ecological ideas experience conformist bias; (3) the differences in popular concept variability indicate that cultural drifts are stronger in disciplinary domains than in cross-disciplinary domains; and (4) the frequency change in popular sustainability ideas also suggests positive selection due to political strategy and governmental behaviour. The study can promote vibrant and resilient ecological knowledge to foster sustainability activities and behaviours.