Species may survive climate change by migrating to track favorable climates and/or adapting to different climates. Several quantitative genetics models predict that species escaping extinction will change their geographical distribution while keeping the same ecological niche. We introduce pollen dispersal in these models, which affects gene flow but not directly colonization. We show that plant populations may escape extinction because of both spatial range and ecological niche shifts. Exact analytical formulas predict that increasing pollen dispersal distance slows the expected spatial range shift and accelerates the ecological niche shift. There is an optimal distance of pollen dispersal, which maximizes the sustainable rate of climate change. These conclusions hold in simulations relaxing several strong assumptions of our analytical model. Our results imply that, for plants with long distance of pollen dispersal, models assuming niche conservatism may not accurately predict their future distribution under climate change.vidence is accumulating that current climate change has already induced extinctions of species (1, 2), and this phenomenon is predicted to accelerate in the next decades (3). In an environment that is changing both in space and in time, species may escape from extinction by changing their geographical distribution such that they track in space the same climatic conditions, by adapting their phenotype to the new climatic conditions where their currently occur, or by a combination of these strategies (4, 5). Poleward and upward altitudinal spatial range shifts of populations have already been observed in many animals and plants (e.g., refs. 1, 6, and 7). Likewise, there is increasing evidence of phenotypic changes induced by climate change, caused by plastic and/or genetic responses (8). The success or failure of these responses strongly depends on dispersal, which influences both colonization and adaptation (3, 9, 10). For plants, the demographic migration (due to seed dispersal) is partially uncoupled from gene flow (due to both pollen and seed dispersal): pollen and seed dispersal are therefore not expected to have the same consequences on spatial range shifts and on ecological niche shifts (9,(11)(12)(13)(14)(15). In this paper, we investigate how the dispersal distance of pollen specifically affects the evolutionary and demographic responses of populations under climate change.The challenges associated with adaptation to climate change, and how theoretical studies have attempted to model the responses to these challenges, can be concretely illustrated with the example of Picea sitchensis (Sitka spruce). This tree species naturally occurs on a limited geographical range along the Pacific coast of North America. Bud set date, a phenotype linked with adaptation to climate, is genetically differentiated throughout the range, linearly decreasing from south to north, which suggests divergent selection on this trait across the range, associated with temperature (16, 17). Likewise, many theoretica...