Plant population differentiation and climate change: responses of grassland species along an elevational gradient

Abstract

Mountain ecosystems are particularly susceptible to climate change. Characterizing intraspecific variation of alpine plants along elevational gradients is crucial for estimating their vulnerability to predicted changes. Environmental conditions vary with elevation, which might influence plastic responses and affect selection pressures that lead to local adaptation. Thus, local adaptation and phenotypic plasticity among low and high elevation plant populations in response to climate, soil and other factors associated with elevational gradients might underlie different responses of these populations to climate warming. Using a transplant experiment along an elevational gradient, we investigated reproductive phenology, growth and reproduction of the nutrient-poor grassland species Ranunculus bulbosus, Trifolium montanum and Briza media. Seeds were collected from low and high elevation source populations across the Swiss Alps and grown in nine common gardens at three different elevations with two different soil depths. Despite genetic differentiation in some traits, the results revealed no indication of local adaptation to the elevation of population origin. Reproductive phenology was advanced at lower elevation in low and high elevation populations of all three species. Growth and reproduction of T. montanum and B. media were hardly affected by garden elevation and soil depth. In R. bulbosus, however, growth decreased and reproductive investment increased at higher elevation. Furthermore, soil depth influenced growth and reproduction of low elevation R. bulbosus populations. We found no evidence for local adaptation to elevation of origin and hardly any differences in the responses of low and high elevation populations. However, the consistent advanced reproductive phenology observed in all three species shows that they have the potential to plastically respond to environmental variation. We conclude that populations might not be forced to migrate to higher elevations as a consequence of climate warming, as plasticity will buffer the detrimental effects of climate change in the three investigated nutrient-poor grassland species.

Constraints to and conservation implications for climate change adaptation in plants

“…This suggests that plasticity may mask local adaptation in the short term, but is not sufficient for long term persistence. Conversely, reciprocal transplant experiments of grassland species along an elevational gradient showed no indication of local adaptation, with consistent advanced reproductive phenology due to plasticity observed in all three species studied (Frei et al 2014). Plasticity has also been demonstrated to assist Pinus species growth and survival under a warmer, drier climate (Richter et al 2012).…”

Ecotypic differentiation in photosynthesis and growth of Eriophorum vaginatum along a latitudinal gradient in the Arctic tundra

“…A population by environment interaction, where local populations demonstrate greater fitness relative to nonlocal populations (i.e., "homesite advantage"), indicates local adaptation (i.e., ecotypic differentiation) (Etterson 2004;Kawecki and Ebert 2004;Macel et al 2007). In Arctic and alpine ecosystems, reciprocal transplants conducted along climatic gradients have demonstrated ecotypic differentiation with respect to climate for numerous species (Bauert 1996;Bennington et al 2012;Chapin and Oechel 1983;Chapin and Chapin 1981;Gonzalo-Turpin and Hazard 2009;McGraw 1987;McGraw and Antonovics 1983;Mooney and Billings 1961;Scheepens et al 2010; but see Fetcher et al (2000) and Frei et al (2014)). Over the last 30 years, the Arctic climate has rapidly changed (IPCC 2007).…”

Variation of vegetative and floral traits in the alpine plant Solidago minuta: evidence for local optimum along an elevational gradient

“…However, knowledge on variations in morphological traits and plant performance in natural populations along elevational gradients is also important to understand the role of natural selection in plant adaptation to alpine environments and plant phenotypic responses to such conditions (Clausen et al 1948;Gonzalo-Turpin and Hazard 2009;Bastida et al 2015). Moreover, it has been emphasized that, in the context of present and predicted future climate changes, knowledge of plant performance along elevational gradients may contribute to an enhanced prediction of plant responses under an altered climate (Theurillat and Guisan 2001;Felde et al 2012;Frei et al 2014b).…”