Seeds at risk: How will a changing alpine climate affect regeneration from seeds in alpine areas?

Abstract

Alpine areas are both regional water reservoirs and zones of high species endemism. Increasing temperatures and earlier snowmelt have already caused upward migration of species, changes in flowering phenology and increasing frost damage in plants. Thus, significant loss of diversity in alpine areas is imminent. Plant migration and distribution shifts occur mainly via seeds, which also provide the genetic diversity required for adaptation. The ability of plants to shift their distribution in response to climate change will depend on seed dispersal, germination and seedling success under new environmental conditions. Despite the critical importance of seeds and seedlings for species adaptation, migration and persistence, the majority of studies concerning climate change in alpine areas have mostly focused on the response of adult plants to warming. Temperature during seed development, as well as the temperature to which seeds are exposed post-dispersal, has been found to have strong effects on seed longevity, germination and seedling survival. Therefore, global change (particularly, warming) is expected to greatly impact regeneration of seeds in alpine areas. Despite evidence that climate change is advancing flowering phenology in several mountain ranges around the world, under natural and artificial warming, the cascade effects that early flowering can have on seeds and seedlings have been poorly studied. Indeed, while a literature search on Web of Science using the search terms “germination”, “alpine plants” and “climate change” revealed 50 studies, of which only 7 directly examined the effect of warming on germination and establishment of seeds of alpine plant species. Here, we discuss the findings of these studies. We identify critical questions regarding seeds and seedlings of alpine species that require urgent research and recommend experimental approaches. Answering these questions will assist in predicting the impacts of global warming and in conservation and management of plants in alpine areas.