Developmental instability as an index of adaptation to drought stress in a Mediterranean oak

• Published in: Ecological indicators Vol. 40; pp. 68 - 75
• Main Authors: Nuche, P., Komac, B., Camarero, J.J., Alados, C.L.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.05.2014; Elsevier
• Subjects: Adaptation; Animal and plant ecology; Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Conservation, protection and management of environment and wildlife; Developmental instability; Drought stress; Fractal dimension; Fundamental and applied biological sciences. Psychology; General aspects; Mediterranean oak; Parks, reserves, wildlife conservation. Endangered species: population survey and restocking; Phenotypic plasticity; Synecology; Drought stress; Phenotypic plasticity; Developmental instability; Mediterranean oak; Fractal dimension; Adaptation; Ecological indicator; Development; Mediterranean region; Environmental monitoring; Water stress; Environmental protection
• ISSN: 1470-160X; 1872-7034
• DOI: 10.1016/j.ecolind.2013.12.023

•We studied levels of stress in a Mediterranean oak in cold, mesic and xeric sites.•We assessed oak response to drought with developmental instability (DI) stress index.•The xeric site showed less DI due to its capacity of adaptation to water-shortage.•There is a trade-off between DI and biomass production when resources are scarce.•DI can serve to assess adaptation of organisms to stressful conditions. An increase in temperature and water deficits caused by the ongoing climate change might lead to a decline growth rates and threaten the persistence of tree species in drought-prone areas within the Mediterranean Basin. Developmental instability (the error in development caused by stress) may provide an index of the adaptability of woody plants to withstand climatic stressors such as water shortage. This study evaluated the effects of drought stress on growth variables in three stands of a Mediterranean oak (Quercus faginea) exposed to differing climatic conditions (xeric, mesic and cooler) along an altitudinal gradient in northeastern Spain, in two climatically contrasting years (wet and dry years). Two indices of developmental instability, fluctuating and translational asymmetries, which reflect environmental stress, were measured in leaves and current-year shoots, respectively. We also measured branch biomass and fractal complexity of branches as indicators of the species’ performance. After a period of drought the individuals’ at the most xeric site presented lower developmental instability and less branch biomass than did the individuals from the mesic and cooler sites. We interpret that difference as an adaptive response to drought which reflects a trade-off between maintenance of homeostasis and growth when water is scarce. The study demonstrated that developmental instability constitutes a useful index to assess the degree of adaptation to stressful environmental conditions. The assessment of developmental instability in sites and years with contrasting climatic conditions provides a means of quantifying the capacity of plants to develop plastic adaptive responses to climatic stress.