Southwest Exotic Plant Information Clearinghouse
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Why Do We Need a Criteria?
Invasive non-native plants collectively constitute one of the gravest threats to biodiversity of natural areas. Humans are responsible, whether intentionally or accidentally, for most introductions and dispersal of non-indigenous plants. Species are introduced to provide food and forage, address a problem such as erosion, or serve as ornamentals. Only a few introduced plants become invasive and cause ecological damage to forests, deserts, wetlands, and riparian areas. By adversely impacting biodiversity, posing health risks, and burdening agriculture, tourism, fisheries, and outdoor recreation, invasive plants inflict serious economic and ecological damage. In Arizona, there are hundreds of non-native plant species yet only a small proportion of introduced species become invasive and cause unwanted impacts to natural communities and biological diversity.
Critical components for protecting native species and natural communities include:
- identifying those non-native species that threaten biodiversity, ecological functions, and values
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prioritizing the most harmful species for early detection and management efforts
Many county, state, and federal agriculture agencies have compiled regulatory noxious weed lists focused on species that affect agricultural production, economic interests, and human health. However, existing regulatory lists most often do not include species that negatively impact native ecosystems.
Likewise, many "weed" or "bad plant" lists exist but often they are:
- site specific
- not based on explicit and uniform factors
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difficult to compare, compile, and defend as objective
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provide little or no explanation to justify their conclusions
The Criteria is a risk assessment that provides a transparent, repeatable, and credible process to identify which non-native plants invade natural areas and threaten biological diversity and ecosystem processes.
Please contact Kathryn Thomas regarding any questions.
