Habitat change, invasive species, over-exploitation, pollution and climate change drive biodiversity loss. Together, these anthropogenic effects may have initiated the sixth mass extinction. Between 15-37% of terrestrial species may be lost by 2050, and the remaining species likely will shift polewards and upwards to create novel assemblages of species. Reliable prediction of which species will go extinct, where they will relocate, and with whom they will associate, can only be achieved through

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... substantial advances in our understanding of the physical and biological world. Indeed, many models associating species with climate change use oversimplified assumptions about the factors that regulate species survival, abundance and distribution. In reality, there are many biotic (e.g. competitors, predators, mutualists) and abiotic (e.g. temperature, moisture) factors that determine a species survival at micro-and macro-habitat scales. Current work typically focuses on a few abiotic factors at macro-habitat scales, leaving high uncertainty in how species will respond to climate change. The best management strategy for preserving biodiversity will, therefore, be a redress of the human footprint on the biosphere. Local initiatives alone may be ineffective. For example, wildlife reserves will be unsuccessful if climate change shifts temperature and rainfall outside the targeted species optimal requirements. If so, management must address whether the target species can migrate from the wildlife reserve toward suitable habitat. As such, conservation strategies must facilitate species movement that tracks favorable climate, via corridor maintenance and/or careful translocation of species to new habitat. The latter option is contentious given that movement of species might prevent extinction but threaten native species in the introduced range. 2 Definition Extinction rates, and changes in the abundances and distributions of species, are accelerating under climate change. To predict and manage the consequences for biodiversity requires substantial advances in our fundamental understanding of the processes and factors that structure ecological communities. Key Information Nobel-prize winning physicist Richard Feynman, defined science as, "...the belief in the ignorance of experts." He meant that science, the body of knowledge about how the world works, must be re-evaluated before being accepted or rejected. It is through such judgment (observation and testing) that scientists hone scientific knowledge. No matter how advanced, this knowledge is always abounded at the edges by uncertainty. The uncertainty grows with the complexity of a problem, and complexity increases with the number of factors that might explain the problem. Our problem is explaining the distribution and abundance of a species, and those of the other species with which it is found (i.e. a community). Our confidence in the answers to this problem are low because many factors affect the distribution and abundance of species, and these factors likely change for each species in a community. Given uncertainty in which species will go extinct, where remaining species will occur, and what assortment of species future communities will contain, this chapter explores: (1) how climate change is affecting biodiversity; and (2) how we predict and might manage biodiversity change.