Seed as a pathway for non-native plant species in Sardinia (IT)
The accidental introduction of non-native plant species via commercial seed contamination is a known pathway for the movement of invasive plant seed. There are numerous examples of invasive plants arriving via this pathway throughout the world. A study on the non-native flora in Sardinia showed that the majority (791 species) were introduced voluntarily, while 140 species were introduced accidentally. In Sardinia, imports of agricultural seed are essential for the industry. Seed is imported from different Italian regions, from other European countries and from Australia. To evaluate the potential of invasive alien plant seed as contaminants of seed (for planting), 39 seed packages were collected and assessed. These comprised 20 packages of novel forage crop cultigens under experimental testing, 10 packages of pet feed (for birds and rodents), 6 packages of lawn mixtures (including one package of grass to be planted for cats) and 3 wildflower mixtures. For each seed package, a subsample of 350 g was screened for the presence of contaminants. If the weight of the seed package was less than 350 g all seeds were sampled. All seeds (commodities and contaminants) were identified to either the family, genus or species level. Ninety-five percent of the seed packages contained seed contaminants. No contaminants were found in the lawn mixture of grass to be planted for cats. A total of 231 contaminant species were found belonging to 88 genera and 34 families. The most common families of seed contaminant were Amaranthaceae, Brassicaceae, Caryophyllaceae, Cyperaceae, Fabaceae, Lamiaceae, Poaceae and Polygonaceae. Of particular interest were the presence of the agricultural weeds Amaranthus sp. and Echinochloa sp. The results show that seed imported into Sardinia presents a risk for the entry of non-native invasive plant species.
Cossu TA, Lozano V, Stuppy W, Brundu G (2019) Seed contaminants: an overlooked pathway for the introduction of non-native plants in Sardinia (Italy). Plant Biosystems doi.org/10.1080/11263504.2019.1701123