At a more local scale, pollen grain also shows evidence of climate change since the last ice age. Since the distribution of vegetation is largely controlled by climate, changes in plant communities, exhibited by pollen grains left behind, can be used to infer how climate has changed at a local scale. Pollen grains are preserved in lakes and river sediments, showing the changes in distribution. For example in Illinois, USA, it is found that there is a high concentration of spruce pollen grains closer to the last ice age which is indicative of a cooler climate. Today, spruce pollen does not exist in the area today, where now it is dominated by oak. This indicates that climate has changed since the last ice age as vegetation distribution adapts to climate changes.