The added complications of climate change: understanding and managing biodiversity and ecosystems

www.frontiersinecology.org © The Ecological Society of America E and biodiversity have long been threatened by natural and anthropogenic stressors (MA 2005; Mooney et al. 2009). A stressor is an activity or phenomenon that induces an adverse effect and therefore degrades the condition and viability of a natural system (EPA 2008). The stressors that have most damaged natural systems fall into four general categories: (1) land-use and land-cover change ([LULCC], including habitat fragmentation and degradation, urbanization, and infrastructure development), (2) biological disruptions (introduction of non-native invasive species, diseases, and pests), (3) extractive activities (such as fishing, forestry, and water withdrawals), and (4) pollution (including chemicals, heavy metals, and nutrients). The combined impacts of these stressors are estimated to have altered more than 75% of Earth’s ice-free land (Ellis and Ramankutty 2008) and virtually all reaches of the world’s oceans (Halpern et al. 2008). Climate change has emerged as a new and increasingly important threat to natural systems (Mooney et al. 2009). Climate change is a stressor in its own right, and it interacts with these other stressors in complex ways. Here we present a conceptual framework of climate interactions with other stressors, survey and categorize current knowledge about the intersection of climate change and these stressors, highlight potential interactions under future climate scenarios, and discuss the implications for developing effective response strategies.