Assessing the invasive risk of two non-native Agrostis species on sub-Antarctic Macquarie Island

作者：Pertierra Luis R^*; Baker Matthew; Howard Chris; Vega Greta C; Olalla Tarraga Miguel A; Scott Jenny

来源：Polar Biology, 2016, 39(12): 2361-2371.

DOI：10.1007/s00300-016-1912-3

• Agrostis stolonifera
• Agrostis capillaris
• Biological invasions
• Ecological modeling
• Biogeographic distributions
• Phenological constraints

Two small swards of two grass species (Agrostis stolonifera and Agrostis capillaris) previously unrecorded on Macquarie Island (54A degrees 30'S, 158A degrees 56'E) were found during the 2013-2014 austral summer. Their discovery leads to an assessment of their introduction status and invasive risk. Several evaluations were conducted on the plants regarding their extent, taxonomy, reproductive status and invasive potential. It is possible that the two species were accidentally introduced by human activities due to their proximity to human-frequented sites. No further occurrences were found, indicating that although the species were established, they were, respectively, restricted to two small swards of less than 1 m(2) each. Observations of floral development in the field at the end of summer suggested that no sexually reproductive material was produced. Indoor cultivation of sampled specimens at the island station showed a faster development with mature flowers at the end of the summer but still no seeds. The bioclimatic niches of the two species were modeled with MaxEnt software. Biomodeling results indicate that reasonably favorable habitat is available on Macquarie Island for the successful colonization of both species. Agrostis stolonifera showed a higher invasion risk than A. capillaris. Our observations indicate that the two species are strong candidates for invading the island despite having phenological constraints. As a result, the two swards were removed by the island's management authority. Further introductions and establishment of non-native plant species are expected to occur on sub-Antarctic islands under current global change scenarios.

• 出版日期2016-12