Functional Traits and Adaptation Mechanisms of Eucalyptus Species in the Congo

Abstract

Background: Adaptation is not only effective by considering the survival of plants, but also by taking into account the traits that support adaptation to environmental changing. Local adaptation occurs because different environmental factors impose different selective pressures across habitats. Understanding the ecophysiological mechanisms underlying survival and growth in plants is crucial for establishing the reasons trade-offs are associated with adaptation.Methods: A comparison provenance test of 29 species of Eucalyptus were used to understand the adaptation strategies on the coastal plains of Pointe-Noire, in the Republic of the Congo. Survival, growth traits and leaves functional traits was jointly measured. Climatic traits of the species origin areas were also studied. Cluster analysis was performed to group species according to their growth strategy.Results: The results suggest that species would be able to survive under current environmental change by adjusting their specific leaf area plasticity. The cluster analysis suggests a subdivision of the 29 species into four groups. The first cluster brings together E.pilularis and E.peltata, with the lowest growth and the lowest specific leaf area. This cluster contains two species totally unsuited to the local conditions of Pointe-Noire. The second cluster contains species with a wide variety of responses as to their growth strategy, and are able to adapt to the local conditions. The third cluster includes a species are specialized in acquiring high proportions of resources while investing very little in growth. The fourth cluster groups the species with a very slow strategy of acquiring and using resources. Leaf anatomy is quite responsive to climatic conditions. Conclusion: By evaluating all aspects of strategies, Eucalyptus species have shown great variation in their functionnal traits and this may explains their diverse ecological range.