sentence: Invasive species are a big problem with prairies.
sentences_after: Since fires cannot burn freely, many new species are taking over, and preventing sunlight from reaching shorter plants. In the United States, European buckthorn is a common problem. Garlic mustard is another. Often areas that once held a hundred different species of plants now only has three or four species.
concept_name: invasive specie
headings: Prairie restoration Invasive plants and trees