Forest herbs in the face of global change: a single-species-multiple-threats approach for Anemone nemorosa

Background - Global environmental changes have become important drivers of plant community shifts and are considered to be threats to biodiversity. Because multiple environmental changes are acting simultaneously, they might antagonistically, analogously or synergistically affect plant populations and communities. Approach - In this review paper, we attempt to take a single-species-multiple-threats approach to gain insights into the complex impacts of global changes. We selected a well-studied forest herb (Anemone nemorosa) as a case and discuss its response to several prevailing environmental threats. Results - Changes in forest management, land use change, acidifying and eutrophying deposition and climate change are the main topics that have been studied for Anemone. Their impacts have basically been studied at three levels of biological organisation: populations, individual ramets and traits. An important finding that emerged in this review is that the human alterations of the environment have ambiguous effects on the performance of Anemone. While some environmental changes were detrimental, others were rather neutral or even beneficial. The cover of Anemone, for instance, increased following the conversion of coppice towards high forest management, but decreased because of soil acidification and reduced soil moisture. Conclusion - Because the multiple threats may have ambiguous effects on plant performance, the ultimate response of an Anemone population turns out to be very complex. To conclude, we emphasise the need for more integrative studies that assess the impacts of multiple global changes on the different levels of biological organisation of a species.