How do introduced species cause problems for biodiversity? What makes a species invasive? When humans introduce non-native species to a new environment, it can have disastrous impacts on native species and the entire ecosystem. Invasive species may also be able to exploit a resource that native species cannot use, which allows them to take hold in the new environment. Introduced into the Western United States, barbed goatgrass thrives in serpentine soils, whereas native plants do not normally grow in them.4 This has given them a solid stronghold in the area. Combined with the fact that grazing animals do not like the taste of them, the grass has spread rapidly throughout California.