I’ve always been interested in how ecosystems are connected at large spatial scales. This concept was developed as “ecological subsidy” in the 1990’s by the late Drs. Polis and Nakano. I took Dr. Mary Power’s application of ecological subsidy called the “resource shed” and sought to spatially delineate them for aquatic resources. A resource shed is an area supplying materials to a receptor, like a point in space or an organism. I initiated, recruited researchers for, and led an inter-agency project to create and apply new methods of spatial source-area identification in watersheds and open waters. In watersheds, we can now specify where water exiting a river mouth originated in the watershed, using a spatially-explicit hydrologic runoff model, model. Output from these models cab be visualized in order to delineate spatial source areas supplying contaminated water within watersheds. The figure shows the Fox River watershed in Wisconsin displaying resource sheds for two different dates, or where water originated in the watershed that exited the river mouth on two different days. Products include: Croley et al. 2008, Raikow et al. 2010, and Raikow and D’Amico 2011.