Rethinking ecology for the Anthropocene
Results/Conclusions: The ongoing environmental changes are already driving changes in species ranges, community composition, and ecosystems, and such changes are expected to continue. What is less appreciated is that these dynamics are likely to involve increasingly strong ecological disequilibria, where biota and ecosystems on one hand and climate on the other becomes mismatched, notably through extinction debts and immigration lags. The consequences can be complex and unexpected ecological outcomes. Current evidence suggests that such lags are likely to be extremely widespread and long lasting. These dynamics together with other human-driven forcings, notably globalization and the resulting human-mediated spread of organisms worldwide, will cause increasing proportions of wild nature around the world to be novel ecosystems. Novel ecosystems are self-perpetuating ecosystems that have resulted from human activities and do not have natural historical precedents. While much debated in recent years, we do not yet have a good understanding how such ecosystems function, notably their capacity to harbor biodiversity, and how they will respond to further Anthropocene changes, notably in climate. Recent years has witnessed an increasing recognition of the role of trophic cascades in shaping ecosystems and maintaining biodiversity, and jointly with this, their strong world-wide attrition due to defaunation. At the same time there is increasing interest in remedying this trophic downgrading, including via usage of non-native species as ecological replacements for extinct species or to promote biodiversity in novel ecosystems. However, only limited empirical work has been done to evaluate how such natural and novel trophic cascades interplay with other Anthropocene dynamics, limiting our ability to guide their usage for biodiversity conservation and ecological restoration.