Text by Lauri Laanisto
Our lab´s current PhD student Alisa Krasnova and former postdoc Lea Hallik have provided some methodological help to Ülo´s old collaborator, Fernando Valladares. Together, with Ana Lázaro‑Nogal as the leading author, they have published a paper in Oecologia titled: “Population differentiation in a Mediterranean relict shrub: the potential role of local adaptation for coping with climate change”.
Author Contribution Statement expresses their contribution laconically: “LH and AK performed soluble carbohydrates analyses”.
But the conception of the paper of course is much wider than mere dissolving of carbohydrates. This study more or less tackles the question of how much physiological variability in drought tolerance in can be found within species range. As the species in focus, spurge olive (Cneorum tricoccon) is narrowly distributed only in the Mediterranean region, soon-to-be climate there will be much drier than at the moment. Thus the functional capability of this rare species´ to tolerate drought stress is more or less as straightforward and self-explanatory approach as it gets.
Plus, it´s high time that the climate change distribution models would become more sophisticated in the sense that they would also include hard core functional data, not just GBIF sample dots. And it´s nice to see such relatively clear patterns from an intraspecific variability study – such studies usually lack elegant patterns, although they almost always find that intraspecific variability is significant (even on global scale – Siefert et al. 2015).
My personal opinion is that the lack of clear patterns is the consequence of insufficient field work – instead of conducting such studies in one place/area and including as many species as possible, the focus should be on grasping the whole distribution range of one or several species. So that you wouldn´t get mixed up in all the potential combinations of intra- and interspecific patterns, which at least at the moment seems to be impenetrable black box. Or if not the whole range, at least the main abiotic/biotic strass factor gradient of that species. Just like Lázaro‑Nogal and others did in this paper!
Full citation: Lázaro-Nogal, A., Matesanz, S., Hallik, L., Krasnova, A., Traveset, A., & Valladares, F. (2015). Population differentiation in a Mediterranean relict shrub: the potential role of local adaptation for coping with climate change. Oecologia, 10.1007/s00442-015-3514-0 (link to full text)
Plants can respond to climate change by either migrating, adapting to the new conditions or going extinct. Relict plant species of limited distribution can be especially vulnerable as they are usually composed of small and isolated populations, which may reduce their ability to cope with rapidly changing environmental conditions. The aim of this study was to assess the vulnerability of Cneorum tricoccon L. (Cneoraceae), a Mediterranean relict shrub of limited distribution, to a future drier climate. We evaluated population differentiation in functional traits related to drought tolerance across seven representative populations of the species’ range. We measured morphological and physiological traits in both the field and the greenhouse under three water availability levels. Large phenotypic differences among populations were found under field conditions. All populations responded plastically to simulated drought, but they differed in mean trait values as well as in the slope of the phenotypic response. Particularly, dry-edge populations exhibited multiple functional traits that favored drought tolerance, such as more sclerophyllous leaves, strong stomatal control but high photosynthetic rates, which increases water use efficiency (iWUE), and an enhanced ability to accumulate sugars as osmolytes. Although drought decreased RGR in all populations, this reduction was smaller for populations from the dry edge. Our results suggest that dry-edge populations of this relict species are well adapted to drought, which could potentially mitigate the species’ extinction risk under drier scenarios. Dry-edge populations not only have a great conservation value but can also change expectations from current species’ distribution models.
Lázaro-Nogal, A., Matesanz, S., Hallik, L., Krasnova, A., Traveset, A., & Valladares, F. (2015). Population differentiation in a Mediterranean relict shrub: the potential role of local adaptation for coping with climate change Oecologia DOI: 10.1007/s00442-015-3514-0