The article "Challenges in the Quest for Keystones" by M. E. Power, D. Tilman, J. A. Estes, B. A. Menge, W. J. Bond, and others, discusses the identification and significance of keystone species in ecosystems. Keystone species are defined as those whose impact on their community or ecosystem is disproportionately large relative to their abundance. The authors clarify the concept of keystone, discuss its relevance to management processes, and suggest additional research needed. They propose a measure called community importance (CI) to quantify the effect of a species on a community or ecosystem trait. The article also explores the distribution of community importance values among species, the context dependency of keystone species, and the challenges in identifying and managing them. The authors emphasize the importance of understanding the role of keystone species in biodiversity conservation and ecosystem management, highlighting the need for more empirical data and theoretical development.The article "Challenges in the Quest for Keystones" by M. E. Power, D. Tilman, J. A. Estes, B. A. Menge, W. J. Bond, and others, discusses the identification and significance of keystone species in ecosystems. Keystone species are defined as those whose impact on their community or ecosystem is disproportionately large relative to their abundance. The authors clarify the concept of keystone, discuss its relevance to management processes, and suggest additional research needed. They propose a measure called community importance (CI) to quantify the effect of a species on a community or ecosystem trait. The article also explores the distribution of community importance values among species, the context dependency of keystone species, and the challenges in identifying and managing them. The authors emphasize the importance of understanding the role of keystone species in biodiversity conservation and ecosystem management, highlighting the need for more empirical data and theoretical development.