Biodiversity - Global biodiversity scenarios for the year 2100

Scenarios of changes in biodiversity for the year 2100 can now be developed based on scenarios of changes in atmospheric carbon dioxide, climate, vege tation, and Land use and the known sensitivity of biodiversity to these cha nges. This study identified a ranking of the importance of drivers of chang e, a ranking of the biomes with respect to expected changes, and the major sources of uncertainties. For terrestrial ecosystems, land-use change proba bly wilt have the largest effect, followed by climate change, nitrogen depo sition, biotic exchange, and elevated carbon dioxide concentration. For fre shwater ecosystems, biotic exchange is much more important. Mediterranean c limate and grassland ecosystems likely will experience the greatest proport ional change in biodiversity because of the substantial influence of all dr ivers of biodiversity change. Northern temperate ecosystems are estimated t o experience the least biodiversity change because major land-use change ha s already occurred. Plausible changes in biodiversity in other biomes depen d on interactions among the causes of biodiversity change. These interactio ns represent one of the largest uncertainties in projections of future biod iversity change.