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Refugia are key environments in biogeography and conservation. Because of their unique eco‐evolutionary formation and functioning, they should display distinct functional trait signatures. However, comparative trait‐based studies of plants in refugia and non‐refugia are lacking. Here, we provide a comparison between resource‐rich (putative microrefugia for species preferring mesic habitats under increasing aridity) and resource‐impoverished woodlands (non‐refugia) around two granite outcrops in south‐western Australia. We measured and compared six functional traits (bark thickness, foliar δ13C, foliar C:N, leaf dry matter content, plant height, specific leaf area) in four woody species. We performed multiple‐trait, multiple‐species and single‐trait, within‐species analyses to test whether plants in resource‐rich habitats were functionally distinct and more diverse than those in the surrounding resource‐impoverished woodlands. We found that species in resource‐rich woodlands occupied larger and distinct multiple‐trait functional spaces and showed distinct single‐trait values (for specific leaf area and bark thickness). This suggests that plants in resource‐rich woodlands can deploy unique and more diverse ecological strategies, potentially making these putative microrefugia more resilient to environmental changes. These findings suggest that species in microrefugia may be characterised by unique functional signatures, illustrating the utility of comparative trait‐based approaches to improve understanding of the functioning of refugia. [ABSTRACT FROM AUTHOR]

Abstract: Plants respond to changing environmental conditions, and their ability to adjust intra‐specifically to such shifts represents an ecological and evolutionary advantage. We studied seven plant traits for two common, rhizomatous granite outcrop species (the fern Cheilanthes austrotenuifolia, and the herb Stypandra glauca) with seasonal foliage during the cooler, wetter winter months at seven sites across an aridity gradient in southwestern Australia. We investigated trait patterns at regional and habitat scale, by investigating changes in trait values along the aridity gradient, and by comparing two different habitats types (sun‐exposed and sheltered). We expected plants occurring in more arid sites and highly irradiated, shallow‐soil (sun‐exposed) habitats, to exhibit traits indicative of more conservative resource acquisition, retention and use strategies. At the habitat scale, we found support for our prediction, with plants in more stressful, sun‐exposed habitats showing traits’ values associated with more conservative strategies (especially for water), such as smaller plants, denser leaves, higher foliar δ13C and C/N. However, at the regional scale many traits displayed the opposite pattern, suggesting less conservative resource acquisition in more arid sites. This evidence was particularly pronounced for specific leaf area (SLA), which exhibited a significant, positive relationship with increasing aridity. We suggest that the unexpected regional trends in foliar traits relate to shorter lived, faster growing leaves linked to highly efficient resource acquisition and use strategies during the shorter growing season in the more arid regions. These highly exploitative strategies may enable plants to avoid climate extremes, that is, hot and dry periods in the more arid sites. Our findings of contrasting foliar traits responses at different scales support the importance of multi‐scale approaches to quantify the role of intraspecific trait variability. [ABSTRACT FROM AUTHOR]