Climate-change impacts on ecological systems: introduction to a US assessment.

As part of the 2014 US National Climate Assessment, over 60 subject-matter experts from government agen-cies, academia, nongovernmental organizations, and the private sector assessed the current and projected impacts of climate change on ecosystems, biodiversity, and ecosystem services. Here, we introduce and pro-vide context for the papers included in this Special Issue, drawing upon the key findings from separate assess-ments of biodiversity, ecosystem structure and function, ecosystem services, climate-change impacts in the context of other stressors, and societal responses to change (ie climate adaptation). We also explain the assess-ment process and show how the current state of knowledge can be used to identify risks and guide future research and management initiatives. [ABSTRACT FROM AUTHOR]