This dissertation introduces the concept of environmental science identity (ESI) as a way to help better understand and support learners’ engagement with the complex, global problems we face today, which require solutions from multiple perspectives. Because examining a learner’s identity incorporates their values, culture, history, and future, using the lens of ESI in environmental and science education enables educators to honor learners’ knowledge and skills in culturally sustaining and meaningful ways. I additionally argue that we must look expansively at learning activities with a learning ecosystem framework to understand the full picture of how ESI is developed. With these two lenses, ESI and the learning ecosystems framework, I examined the relationship between youth development of ESI and their learning ecosystems, as well as how youth learning ecosystems may be resilient in the face of systemic disturbances like the COVID-19 pandemic in 2020-22. In Chapter 2 I argue that zoos and aquariums need to bring to bear the extensive theory and research on the construct of identity, particularly ESI, and consider the learning ecosystems in which they are embedded, in order to meet their missions of environmental conservation and inclusion. Chapter 3 is an empirical study of how environmental science learning ecosystems support ESI development, as well as the related but distinct construct of environmental identity, in middle and high school youth in urban settings. Through analysis of interviews I found that large ecosystems or deep engagement in activities were more likely to support ESI and environmental identity development. I also found that key material and social resources for identity development were unequally distributed across contexts for learning. Chapter 4 is a mixed-methods investigation of the impact of the COVID-19 pandemic on environmental science learning ecosystems. Through quantitative analysis of a retrospective pre- and during-pandemic survey of the frequency of learning activities, and semi-structured interviews with selected youth, I found that youth increased their engagement in activities overall with significant increases in gardening, hiking or camping, and noticing the plants and animals around them. Despite fewer activities available overall, these youth deepened their engagement in activities that interested them that were still available during the COVID-19-related shutdowns, illustrating the resilience of young people and ways in which the natural world provided science engagement amidst the stresses of the pandemic.