In this report we evaluate adaptation issues for natural ecosystems. We will specifically focus on the interactions with the abiotic environment of plants and animals, along with other organisms with which they interact (e.g., disease-causing bacteria and viruses). We further limit ourselves to natural ecosystems in which the predominant vegetation has developed without having been planted, irrigated, or fertilized. Most of the natural lands in the United States are managed by federal or state governments. Agricultural lands— including range grazing lands — are dealt with in a related adaptation report. This will evaluate the potential magnitudes and challenges facing terrestrial ecosystems in the United States in adapting to changing climate over the next 30-50 years. Our report will not address attribution or mitigation of climate change, as these topics have been dealt with in many other forums. We will begin with a brief summary of the current trajectory of the changing climate in the United States, including both temporal and spatial patterns. We will then relate these trends to ecosystem impacts and vulnerabilities
