Human alterations to the environment such as land-use changes, eutrophication and climate change have elevated the rate of species’ extinction to a level on par with historical mass extinction events. In temperate forests, biodiversity is mainly a function of the herbaceous understorey community. Many forest understorey plants, however, are not able to track land-use and climate change due to their limited colonisation capacities. In addition, probably due to the greater structural complexity and pivotal role of light availability in forests, evidence is now increasing that the effects of human alterations to both nutrient cycles and the climate system are often buffered due to shading in forests. I will present our research on the (interactive) effects of climate change, enhanced nitrogen inputs, and light availability on (i) the growth and reproduction of a selection of forest plants, and (ii) the composition and diversity of understorey plant communities in European and eastern North American temperate forests