Green and senescent leaf phenolics showed spatial autocorrelation in a Quercus robur population in northwestern Spain

Intraspecific variation in polyphenols may be important both for the resistance of plants to herbivory and for nutrient cycling in terrestrial ecosystems. The spatial pattern and scale of polyphenol concentration in natural populations are practically unknown, despite multiple evidence that resources influencing leaf phenolics (such as light or nutrient availability) show spatial dependence at the scale of meters to tens of meters. By using geostatistical methods, we evaluated the spatial variability in polyphenol concentration in green and senescent leaves in a pedunculate oak (Quercus robur L.) population of 125 individuals. The spatial pattern of light and nutrient availability for plants was also evaluated. Leaf polyphenols were more variable than other leaf properties, and green polyphenols were significantly correlated with radiation, leaf mass per unit area and leaf N concentration. Both green and senescent leaf polyphenol concentration showed spatial dependence at distances below 6 to 10 m, with structural (spatial) variance explaining between 50 and 80% of the total variance. The variance not explained by space was assumed to be due to individual genotypic variability. Stochastic maps of leaf phenolics in the area showed that the probability of finding high phenolics level was not random. These findings may be important to understand the spatial heterogeneity of plant-herbivore interactions, leaf litter decomposition and mineralization rate.