Pest defences under weak selection exert a limited influence on the evolution of height growth and drought avoidance in marginal pine populations.


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Authors
Ratcliffe, Blaise 
Klutsch, Jennifer G 
Wei, Xiaojing 
Abstract

While droughts, intensified by climate change, have been affecting forests worldwide, pest epidemics are a major source of uncertainty for assessing drought impacts on forest trees. Thus far, little information has documented the adaptability and evolvability of traits related to drought and pests simultaneously. We conducted common-garden experiments to investigate how several phenotypic traits (i.e. height growth, drought avoidance based on water-use efficiency inferred from δ13C and pest resistance based on defence traits) interact in five mature lodgepole pine populations established in four progeny trials in western Canada. The relevance of interpopulation variation in climate sensitivity highlighted that seed-source warm populations had greater adaptive capability than cold populations. In test sites, warming generated taller trees with higher δ13C and increased the evolutionary potential of height growth and δ13C across populations. We found, however, no pronounced gradient in defences and their evolutionary potential along populations or test sites. Response to selection was weak in defences across test sites, but high for height growth particularly at warm test sites. Response to the selection of δ13C varied depending on its selective strength relative to height growth. We conclude that warming could promote the adaptability and evolvability of growth response and drought avoidance with a limited evolutionary influence from pest (biotic) pressures.

Description

Peer reviewed: True


Funder: University of Cambridge; Id: http://dx.doi.org/10.13039/501100000735

Keywords
Pinus contorta, climate change, common-garden approach, drought, forest pests, trait interactions, Climate Change, Droughts, Forests, Pinus, Trees
Journal Title
Proc Biol Sci
Conference Name
Journal ISSN
0962-8452
1471-2954
Volume Title
Publisher
The Royal Society