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Initiatives by topic
The ecology of the state of Iowa has been heavily affected by agricultural production, but remaining natural areas reflect a wide varieties of environmental niches. 
Whiterock Conservancy, (Wikipedia): 501(c)(3) land trust located in west-central Iowa that stewards over 4,000 acres of contiguous land located in the Middle Raccoon River watershed, and an additional 1,000 non-contiguous land located in the Brushy and Middle Raccoon River watersheds. The Whiterock landscape almost exclusively made possible by an extraordinary planned land gift from the Garst family to Whiterock Conservancy. The landscape is a mosaic of agricultural land, wetlands, preserved prairie and oak savanna, riverine woodlands, and upland forest. The land is used for recreation, environmental conservation, and for the production of agricultural products, and is managed as a working landscape where cultural, environmental, agricultural, and recreational land uses are held in equal importance.
Wikipedia: Cycling in Iowa (category)
Resources: Creating change in the food system, The role of regional food networks in Iowa, March 2012 (PDF)
There is a dearth of natural areas in Iowa; less than 1% of the tallgrass prairie that once covered most of Iowa remain intact, only about 5% of the state's prairie pothole wetlands remain, and most of the original forest has been lost. Iowa ranks 49th of U.S. states in public land holdings. 
Sustainable transport activism
Wikipedia: Hiking trails in Iowa (category)
News and comment
Iowa’s Climate-Change Wisdom, November 20 
Citizens data initiative
Energy Data & Statistics for Iowa, from the U.S. Department of Energy