Is fluctuating asymmetry a reliable indicator of a population's state of adaptation? Does it respond in a predictable way to stress? How is it best employed by evolutionary biologists? To answer these questions, we studied leaf asymmetry of twelve species of vascular plants growing under contrasting microclimates on the opposing slopes of 'Evolution Canyon,' Nahal Oren, Mount Carmel, Israel. We applied similar sampling and measurement techniques to all 12 species, and used power transformations to correct for size scaling. Leaves of the trees Quercus calliprinos and Pistacia palaestina were significantly more asymmetrical on the microclimatically more fluctuating, drier, and savannah-like south-facing 'African' slope. Leaves of the shrub Calicotome villosa were significantly more asymmetrical on the microclimatically less variable, shadier, and maquis-like north-facing 'European' slope. Differences in fluctuating asymmetry were negatively correlated with differences in local abundance; species displayed higher fluctuating asymmetry on the slope where they were less abundant. The results obtained in the present study additionally suggest that the 'African' slope of 'Evolution Canyon' is only severely stressful for species on the margins of their adaptive zone. Similarly, the 'European' slope is only severely stressful for species on the margins of their, different, adaptive zone. Many plant species can adapt to both slopes.
- Fluctuating asymmetry
- Power transformation
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics