The Atlas region has a number of introduced species. Some appear to be harmless, localized introductions. Others are invasive and cause considerable damage to the ecosystem. Invasive species rank second (habitat destruction is first) as an ecological threat to biodiversity. They often out-compete native species for habitat and resources, carry disease, and prey on the local species. Some of the most serious threats to native amphibians and reptiles are introduced invasive amphibians and reptiles. For instance, the detrimental effects of the invasive American Bullfrog is one example of an introduced amphibian that negatively impacts native amphibians and reptiles.