Do novel ecosystems provide habitat value for wildlife? Revisiting the physiognomy vs. floristics debate

Although novel ecosystems are increasing globally, their utility for biodiversity conservation is poorly understood. Native fauna are predicted to use novel ecosystems when those ecosystems provide structure and resources similar to the native habitat. We modified existing terminology on wildlife functional groups to develop a conceptual model that illustrates fundamental differences in how native wildlife respond to novel ecosystems: novel ecosystem avoiders, novel ecosystem utilizers, and novel ecosystem flourishers. We postulate that species membership in these functional groups is related to the relative importance habitat physiognomy and floristics play in habitat selection cues. An excellent opportunity to test this conceptual model exists with birds in historic and novel ecosystems. A long‐standing, equivocal literature investigating relative contribution of physiognomy vs. floristics to avian abundance and community diversity in native ecosystems exists. Using data from grassland and woodland biomes in western North America (Oregon, USA) and Western Australia, respectively, we evaluated use of habitats by indigenous bird species in relation to physiognomy and floristics. Our two case studies represent two extremes on the novelty spectrum: (1) urban gardens in the metropolitan region of Perth, Western Australia, which are designed ecosystems that vary in the percentage of native plantings; and (2) the Zumwalt Prairie in northeastern Oregon where native grassland plants still dominate the ecosystem but non‐native plants are present and available for use as breeding sites. Using an information‐theoretic perspective, we asked whether habitat use based on occurrence (Perth gardens) or breeding success (Oregon grassland) was best explained by physiognomy, floristics, or both. Using these two case studies, our evidence shows that species or guilds within a community will not respond equally to novelty as predicted. We found strong evidence for only one taxon showing sensitivity to floristics and two to physiognomy. All taxa considered were either grouped as novel ecosystem avoiders or utilizers; no flourishers were identified. These results suggest novel ecosystems providing appropriate physiognomy can provision suitable habitat for some taxa.