Data from: Warming had contrasting effects on the importance of facilitative interactions with a cushion nurse species on native and non-native species in the high-Andes of central Chile

Alpine habitats are regarded as particularly vulnerable to the effects of
climate change. On one hand, global warming is supposed to contributes to
alpine environments becoming less stressful. On the other hand, altered
snowpack due to warmer temperatures can intensify the stress in these
habitats. The presence of non-native plants on some of these habitats is
due to the facilitative effects exerted by native nurse plants, becoming
an additional threat. According to the stress gradient hypothesis the
importance of facilitative interactions with nurse species is expected to
diminish as environmental harshness decreases due to climate change, yet
remains important if climate change heightens the stress in alpine
habitats. However, the responses also depend on climate change's
impact on the nurse species. We conducted an experimental warming
experiment in the Andes of the central Chile to assess the effects of
warmer temperatures on the growth, reproduction and photochemical
efficiency of the cushion nurse plant Azorella madreporica. Further we
performed a cushion removal experiment involving three native species
(Gamocarpha ventosa, Nocaccea magellanica and Rytidosperma pictum) and two
non-native species (Cerastium arvense and Taraxacum officinale) to assess
whether facilitative interactions changed with warming. We expected that
under warmer conditions facilitation continued be important for the native
species but decreased for the non-natives as the latter are abundant at
warmer low elevations. We found that warmer conditions increased the
photochemical efficiency and growth of the nurse cushions. Removal of
cushions resulted in high mortality rates for all species. However, under
warmer conditions, native species exhibited lower survival rates, whereas
non-natives showed no significant changes compared to control groups. In
summary, warmer temperatures were beneficial for the nurses maintaining
the importance of facilitative interactions for native species, but not
for the non-natives.