OOS 5-1 - A framework for understanding the ecological role of structural diversity

Background/Question/Methods
One of the fundamental goals in ecology is to understand the identity, abundance, and arrangement of life forms on Earth, because such variation underpins the emergence of ecological patterns and processes. Structural diversity—the three-dimensional (3D) volumetric capacity, physical arrangement, and identity/traits of biotic components of an ecosystem—is intrinsically linked to ecological processes. Despite being recognized in earlier ecological studies and with deep historical roots in forestry, remote sensing, and community and landscape ecology, structural diversity has been largely overlooked due to a lack of a theoretical foundation and tools to effectively measure it. There is still a relatively limited understanding of the linkages of structural diversity to broader ecological patterns and processes. Here, we provide a framework for structural diversity that can facilitate its characterization across space and time and promote theory focused on understanding its role in ecology.

Results/Conclusions
The main tenet of our structural diversity framework is that (1) structural diversity is a key ecosystem characteristic that describes the 3D volumetric capacity, physical arrangement, and identity/traits of biotic components in an ecosystem, and (2) is an integral part of ecological patterns and processes through its influence on the distribution and interactions of energy and matter. We first give a broad overview of what structural diversity is and explore its role in driving ecological patterns and processes. We then discuss how the interplay of genetic and environmental factors underpin structural diversity, allowing for a potentially unique synthetic approach to explain ecosystem function. We propose a practical approach with which scientists can test the ecological role of structural diversity at biotic-environmental interfaces, along with examples of structural diversity research. Finally, we discuss future directions for integrating structural diversity into ecological theory and management across scales.