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

journal contribution
posted on 2023-05-19, 00:32 authored by Pertierra, LR, Baker, M, Howard, C, Vega, GC, Olalla-Tarraga, MA, Jennifer Scott
Two small swards of two grass species (Agrostis stolonifera and Agrostis capillaris) previously unrecorded on Macquarie Island (54°30′S, 158°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 m2 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.

History

Publication title

Polar Biology

Volume

39

Issue

12

Pagination

2361-2371

ISSN

0722-4060

Department/School

School of Geography, Planning and Spatial Sciences

Publisher

Springer-Verlag

Place of publication

175 Fifth Ave, New York, USA, Ny, 10010

Rights statement

Copyright 2016 Springer-Verlag Berlin Heidelberg

Repository Status

  • Restricted

Socio-economic Objectives

Control of pests, diseases and exotic species in coastal and estuarine environments

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