Demographic compensation and tipping points in climate-induced range shifts of tundra plants
Professor William Morris, Department of Ecology and Genetics, Uppsala University, SwedenOne potential consequence of climate warming is a shift in the geographical ranges of species. For immobile organisms such as plants, range contraction at the low-latitude or low-elevation range limit would likely be caused by local population decline and eventual extinction. I will report on a long-term study quantifying the demography of two tundra plant species across their latitudinal ranges in North America. While we see some demographic processes deteriorating as the southern range limit is approached, others improve, and this “demographic compensation” may be buffering the geographical ranges against effects of climate warming. However, we also see the possibility for rapid population collapse once a “tipping point” in warming has been exceeded. I will also report on on-going work in North America, and a new collaborative project across the range of one study species (Silene acaulis) in across its Europe range (from Spain to Switzerland to Sweden).