The same warming chambers pushed Antarctica's two flowering plants in opposite directions

The opposite signs are the problem. Fit a warming response function to either of these species and it predicts the wrong direction for the other. Both sets of traits came off plants in the same treatment at the same site ^[17]. Antarctica's entire native vascular flora is these two species ^[2].

The chambers warm passively, without heaters or power ^[2], and the authors say that design let them capture ecologically relevant aspects of climate change such as increases in freeze-thaw events, not only a rising mean temperature ^[8]. Leaf hydraulic traits, xylem anatomy and photosynthetic performance were assessed together, in both species, which the authors say had not been done in the field before ^[7].

The account of the Physiologia Plantarum paper ^[13] reports the direction of each change. It does not give the warming increment inside the chambers, the number of plots, or the size of the changes in conductivity and photosynthesis ^[16]. That limits extrapolation. Whether the warmed plots gain or lose carbon overall depends on the relative size of the hairgrass reduction and the pearlwort increase.

Patricia Sáez of Universidad de La Frontera is one of the study's authors. "These results show that coordination between hydraulic function and photosynthesis is key to the survival of Antarctic plants, but that each species has addressed this challenge differently: one prioritizing stability and hydraulic safety, the other plasticity and rapid acclimation," she said ^[9][12].

Lohengrin Cavieres of Universidad de Concepción took the contrast further, to why the two plants share the ground at all. "These two plants have coexisted in Antarctica for a long time," he said, "and this study shows us one possible reason why: they do not compete for resources in the same way because they respond to warming differently" ^[10][12]. The measurements described are plant traits, not interactions between species ^[7]. So the resource-partitioning account interprets the trait contrast; it does not test it.

Pearlwort's response also came with structure behind it: shifts in vascular anatomy, and a cushion growth form that helps conserve heat ^[5]. That is the kind of change a seven-year experiment can show and a single summer cannot.

The plots were established in 2012 and the warming ran seven years, which puts the exposure at roughly 2012 to 2019 ^[15]. Over recent decades, according to Cavieres, both species have managed to coexist and expand in Antarctica despite regional warming ^[14].