Recovery of silver fir ( Abies alba Mill.) seedlings from ungulate browsing mirrors soil nitrogen availability - INRAE - Institut national de recherche pour l’agriculture, l’alimentation et l’environnement Accéder directement au contenu
Article Dans Une Revue Tree Physiology Année : 2021

Recovery of silver fir ( Abies alba Mill.) seedlings from ungulate browsing mirrors soil nitrogen availability

Résumé

Abstract Abies alba (Mill.) has a high potential for mitigating climate change in European mountain forests; yet, its natural regeneration is severely limited by ungulate browsing. Here, we simulated browsing in a common garden experiment to study growth and physiological traits, measured from bulk needles, using a randomized block design with two levels of browsing severity and seedlings originating from 19 populations across Switzerland. Genetic factors explained most variation in growth (on average, 51.5%) and physiological traits (10.2%) under control conditions, while heavy browsing considerably reduced the genetic effects on growth (to 30%), but doubled those on physiological traits related to carbon storage. While browsing reduced seedling height, it also lowered seedling water-use efficiency (decreased $\delta ^{13}$C) and increased their $\delta ^{15}$N. Different populations reacted differently to browsing stress, and for seedling height, starch concentration and $\delta ^{15}$N, population differences appeared to be the result of natural selection. First, we found that populations originating from the warmest regions recovered the fastest from browsing stress, and they did so by mobilizing starch from their needles, which suggests a genetic underpinning for a growth-storage trade-off across populations. Second, we found that seedlings originating from mountain populations growing on steep slopes had a higher $\delta ^{15}$N in the common garden than those originating from flat areas, indicating that they have been selected to grow on N-poor, potentially drained, soils. This finding was corroborated by the fact that nitrogen concentration in adult needles was lower on steep slopes than on flat ground, strongly indicating that steep slopes are the most N-poor environments. These results suggest that adaptation to climate and soil nitrogen availability, as well as ungulate browsing pressure, co-determine the regeneration and range limit of silver fir.

Dates et versions

hal-03411437 , version 1 (02-11-2021)

Identifiants

Citer

Katalin Csilléry, Nina Buchmann, Oliver Brendel, Arthur Gessler, Alexandra Glauser, et al.. Recovery of silver fir ( Abies alba Mill.) seedlings from ungulate browsing mirrors soil nitrogen availability. Tree Physiology, 2021, ⟨10.1093/treephys/tpab105⟩. ⟨hal-03411437⟩
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