Although novel ecosystems are increasing globally, their utility for biodiversity conservation is poorly understood. Native fauna are predicted to use novel ecosystems when they 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 structure and composition play in habitat selection cues. An excellent opportunity to test this conceptual model exists with birds in historic and novel ecosystems. Birds are excellent model organisms to test predictions about the role of novelty in providing suitable wildlife habitate because there exists a long-standing, equivocal literature investigating relative contribution of physiognomy versus floristics to avian abundance and community diversity in native ecosystems which can be used as the theoretical basis for investigations. 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 breeding sites. Using an information-theoretic perspective, we asked whether bird use (Perth gardens) or breeding success (Oregon grassland) was best explained by composition, structure, or both.
Results/Conclusions
Across the broad gradient of novelty considered in this study, we found strong evidence for only one taxon showing sensitivity to composition and two to structural shifts. All taxa considered were either grouped as novel ecosystem avoiders or utilizers; no flourishers were identified. These results suggest novel ecosystems provision meaningful habitat for some taxa. Given that habitat use of only one taxon showed sensitivity to floristics we suggest that assemblages in these two study areas are largely agnostic to species composition and respond more strongly to structure under current conditions. Thus, our data support the predictions that novelty provisioning structure can provide suitable habitat for some native vertebrates.