Netherlands Polar Data Center

Polar ecosystems are threatened by non-native plants and this risk will increase with climate warming. Non-native plant growth depends on Antarctic environmental conditions and substrates, but these influences are poorly quantified. Under laboratory conditions we quantified growth of Holcus lanatus, Trifolium repens and Taraxacum officinale, across nine sub-and maritime Antarctic substrates with varying characteristics. This included, among others, variation in carbon (0.2-27.0%), nitrogen (0.03-2.1%) and phosphorus (0.04-0.54%) contents, under simulated Antarctic conditions (2 °C) and a warming scenario. Legacy-effects from an established non-native chironomid midge (Eretmoptera murphyi) and non-native grasses were included. Holcus lanatus and T. repens grew best in organic and nutrient-rich substrates, while T. officinale growth was poorly correlated with substrate characteristics. Warming increased plant size 1-3 times, but inconsistently across species and substrates, suggesting that climate change impacts on plant growth will vary across the maritime Antarctic. A variable response was also observed with legacy-effects of E. murphyi, while non-native grasses increased H. lanatus and T. repens plant size, but not that of T. officinale. Plant growth was positively correlated with substrate organic- and phosphorus-content, and this information was used to trial a novel approach to identifying sites at ‘risk’ from plant invasions in the maritime Antarctic.

Experimental study in the lab