A new program, Teaching Ecological Complexity, is working to develop a heightened capacity for ecological thinking among high school biology teachers. Funded by an NSF grant (ESIE # 0554379), the training program uses immersion in challenging ecology research projects and tools and procedures related to qualitative modeling and simulation. Science teachers work in partnership with ecologists, conducting field research projects and using conceptual qualitative modeling in each of five simultaneous training workshops at HJ Andrews LTER (temperate forest), Luquillo LTER (tropical forest), Jornada LTER (Chihuahuan Desert), Central Arizona Urban Desert LTER, and Shortgrass Steppe LTER (dry grasslands). The differences and similarities between these ecosystems are emphasized through intersite comparisons of three datasets: terrestrial arthropod diversity, litter decomposition, and vegetation cover. A series of qualitative conceptual models are drawn by teachers as they proceed through the steps of inquiry. The reflective use of these models helps teachers to restructure their understanding about ecosystem processes. This project also provides training for professional development providers from nature centers, with an opportunity to extend their ecological knowledge and teacher workshop leadership skills at training of trainers sessions. This collaboration has lead to meaningful real-world opportunities that participating teachers incorporate into their students’ work; this authenticity is the “hook” many teachers find so successful in generating student interest. Teachers' ecological content knowledge, knowledge about ecological complexity, and classroom practices are measured before and after their participation in these training sessions. Results of the impact on teacher learning from each site's training programs, the value of the inter-site comparisons of data, descriptions of two participating teachers' work with their classrooms, and results from our training sessions that help nature centers to develop their own teacher training sessions will be discussed. Overall impacts of these approaches in developing ecological literacy will also be discussed.