Generalised seed mortality driven by heat shock in woody plants from Mediterranean Chile

Background Wildfires have shaped plant traits and ecosystems worldwide. Most research on the relevance of fire on plant evolution comes from Mediterranean-type ecosystems (MTEs), where a great proportion of the studied species have fire-stimulated germination. However, seed fire ecology is widely unknown for the woody flora of the Chilean matorral, the only MTE where natural fires are infrequent owing to the scarcity of non-anthropogenic ignition sources. Aim The study aimed to evaluate whether seed sensitivity to heat is generalised among the woody species of the matorral. Methods We performed heat shock experiments on the seeds of 21 woody plant species not previously assessed. These species and those from previous studies were classified according to their response as stimulated, tolerant and inhibited. The preponderance of any of these categories was statistically evaluated. Key results Exposure to 100°C for 5 min significantly decreased seed survival in all studied species. Conclusions Seed persistence to fire is less common than previously reported among woody plants from the Chilean MTE. Implications Increased wildfire events in the future may erode the genetic diversity of the Chilean flora. Germplasm banks may become crucial in post-fire restoration programs in this ecoregion, where the landscape has become increasingly flammable.