Warming impacts potential germination of non-native plants on the Antarctic Peninsula

Stef Bokhorst,Rien Aerts,Peter Convey,Angélica Casanova-Katny

doi:10.1038/s42003-021-01951-3

Abstract

The Antarctic Peninsula is under pressure from non-native plants and this risk is expected to increase under climate warming. Establishment and subsequent range expansion of non-native plants depend in part on germination ability under Antarctic conditions, but quantifying these processes has yet to receive detailed study. Viability testing and plant growth responses under simulated Antarctic soil surface conditions over an annual cycle show that 16 non-native species, including grasses, herbs, rushes and a succulent, germinated and continued development under a warming scenario. Thermal germination requirement (degree day sum) was calculated for each species and field soil-temperature recordings indicate that this is satisfied as far south as 72° S. Here, we show that the establishment potential of non-native species, in number and geographical range, is considerably greater than currently suggested by species distribution modelling approaches, with important implications for risk assessments of non-native species along the Antarctic Peninsula.

Highlights

The Antarctic Peninsula is under pressure from non-native plants and this risk is expected to increase under climate warming
Antarctic temperature conditions were experimentally simulated in climate chambers in the Netherlands based on (a) high spatial and temporal resolution seasonal soil surface temperature records from the Antarctic Peninsula[32], and (b) a climate warming scenario where summer temperatures are raised by 5 °C, to assess the influence of warming on germination and subsequent growth (Supplementary Fig. 1)
We find that under current climate conditions the soil surface temperature regimes along the Antarctic Peninsula are suitable for 16 non-native species from 7 different plant families

Summary

Introduction

The Antarctic Peninsula is under pressure from non-native plants and this risk is expected to increase under climate warming. Testing directly whether different non-native plant species/types can germinate and survive in Antarctic soils under realistic multiseason edaphic temperature regimes will provide important new information to enhance and improve modelling approaches applied in attempts to predict establishment risk in Antarctica[12,16,29]. We use our results to quantify species-specific degree day sum requirements for seed germination in Antarctic soil to map their potential distribution under contemporary conditions based on available soil surface temperature recordings from the field. We find that under current climate conditions the soil surface temperature regimes along the Antarctic Peninsula are suitable for 16 non-native species from 7 different plant families These findings have important implications for risk assessments of non-native species along the Antarctic Peninsula

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