The phytosanitary risks posed by seeds for sowing trade networks

Area of Science:

• Agricultural Science
• Biosecurity
• Ecology

Background:

• Global seed systems are crucial for food security and rural livelihoods.
• Seed contaminants, including weeds, pests, and diseases, pose significant risks to agriculture and ecosystems.
• Existing regulatory controls have been in place since the 1800s, but seed contaminants are still implicated in invasive species and agricultural diseases.

Purpose of the Study:

• To assess biosecurity risks in international forage crop seed trade networks.
• To model the spread of hypothetical contaminants through global seed trade networks.
• To compare risk assessments based on network connectivity versus trade volume.

Main Methods:

• Utilized network analysis to model contaminant spread in international seed trade.
• Estimated dispersal probabilities from New Zealand's border security interception data.
• Focused on ryegrass and clover seed trade as a case study.

Main Results:

• Complex global seed trade networks were identified, spanning over 134 countries for ryegrass and 110 for clover.
• Simulations indicated potential contaminant dispersal to numerous countries within 10 time-steps.
• Biosecurity risk assessment varied significantly when considering network position compared to trade volume alone.

Conclusions:

• Biosecurity risk in seed trade is influenced by network position, number of trading connections, and trade volume.
• Current regulatory measures may not fully capture the risks associated with unregulated contaminants.
• Enhanced risk mitigation strategies, including comprehensive species lists, inspection protocols, and field surveillance, are recommended.