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Summary Phenotypic and genomic diversity inArabidopsis thalianamay be associated with adaptation along its wide elevational range, but it is unclear whether elevational clines are consistent among different mountain ranges.We took a multi‐regional view of selection associated with elevation. In a diverse panel of ecotypes, we measured plant traits under alpine stressors (low CO2partial pressure, high light, and night freezing) and conducted genome‐wide association studies.We found evidence of contrasting locally adaptive regional clines. Western Mediterranean ecotypes showed low water use efficiency (WUE)/early flowering at low elevations to high WUE/late flowering at high elevations. Central Asian ecotypes showed the opposite pattern. We mapped different candidate genes for each region, and some quantitative trait loci (QTL) showed elevational and climatic clines likely maintained by selection. Consistent with regional heterogeneity, trait and QTL clines were evident at regional scales (c. 2000 km) but disappeared globally. Antioxidants and pigmentation rarely showed elevational clines. High elevation east African ecotypes might have higher antioxidant activity under night freezing.Physiological and genomic elevational clines in different regions can be unique, underlining the complexity of local adaptation in widely distributed species, while hindering global trait–environment or genome–environment associations. To tackle the mechanisms of range‐wide local adaptation, regional approaches are thus warranted.
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Human trampling disturbance exerts different ecological effects at contrasting elevational range limits
Abstract Shifts in species geographic distributions in response to climate change have spurred numerous studies to determine which abiotic (e.g. climatic) and, less commonly, biotic (e.g. competitive) processes determine range limits. However, the impact of disturbances on range limits and their interactions with climatic and biotic effects is not well understood, despite their potential to alter competitive relationships between species or override climatic effects. Disturbance might have differential effects at contrasting range limits, based on Darwin's theory that biotic interactions set abiotically benign range limits and abiotic factors set abiotically stressful range limits.We predicted that plants at lower elevation (abiotically benign) range limits experience a net positive effect of disturbance, whereas those at higher elevation (abiotically stressful) range limits experience a net neutral effect. We examined plant populations along elevational gradients in the Colorado Rocky Mountains, in order to quantify the effects of human trampling disturbance at lower and upper elevational range limits of the common alpine cushion plantsSilene acaulisandMinuartia obtusiloba.Our results are consistent with Darwin's theory. A disturbance‐mediated reduction of competitive effects increases the performance of cushion plants at lower elevations, suggesting a range limit set by biotic factors. At higher elevations, where biotic interactions are minimal, disturbance has neutral or negative effects on cushion plants.Synthesis and applications. Human trampling disturbance exerts differential effects on alpine cushion plant populations at contrasting range limits, emphasizing the need to account for the effects of climate change into the management and conservation of disturbed areas. Disturbance can diminish plant–plant competitive interactions at lower elevational range limits, and thus possibly stabilize alpine species populations susceptible to climate change‐mediated encroachment by lower elevation species. Conservation and management approaches should therefore particularly account for the differential effects of disturbance across climatic gradients.
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- Award ID(s):
- 1753954
- PAR ID:
- 10461193
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Journal of Applied Ecology
- Volume:
- 56
- Issue:
- 6
- ISSN:
- 0021-8901
- Page Range / eLocation ID:
- p. 1389-1399
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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