Costs of female reproduction in a conifer tree: a whole‐tree level assessment

Abstract

Summary1. Costs of reproduction lie at the core of basic ecological and evolutionary theories, and their existence is commonly invoked to explain adaptive processes. Despite their sheer importance, empirical evidence for the existence and quantification of costs of reproduction in tree species comes mostly from correlational studies, while more comprehensive approaches remain missing. Manipulative experiments are a preferred approach to study cost of reproduction, as they allow controlling for otherwise inherent confounding factors like size or genetic background. 2. Here, we conducted a manipulative experiment in a Pinus halepensis common garden, removing developing cones from a group of trees and comparing growth and reproduction after treatment with a control group. We also estimated phenotypic and genetic correlations between reproductive and vegetative traits. 3. Manipulated trees grew slightly more than control trees just after treatment, with just a transient, marginally non-significant difference. By contrast, larger differences were observed for the number of female cones initiated 1 year after treatment, with an increase of 70% more cones in the manipulated group. Phenotypic and genetic correlations showed that smaller trees invested a higher proportion of their resources in reproduction, compared with larger trees, which could be interpreted as an indirect evidence for costs of reproduction. 4. Synthesis. This research showed a high impact of current reproduction on reproductive potential, even when not significant on vegetative growth. This has strong implications for how we understand adaptive strategies in forest trees and should encourage further interest on their still poorly known reproductive life-history traits.

Effects of climate on reproductive investment in a masting species: assessment of climatic predictors and underlying mechanisms

“…larger trees have more available resources and are less likely to exhibit allocation constraints), we included basal tree diameter as a covariate in this statistical model (Almqvist, Jansson & Sonesson ; Smaill et al . ; Santos‐del‐Blanco & Climent ).…”

“…To account for effects of tree size which have previously been shown to influence the magnitude of reproductive trade-offs (i.e. larger trees have more available resources and are less likely to exhibit allocation constraints), we included basal tree diameter as a covariate in this statistical model (Almqvist, Jansson & Sonesson 2001;Smaill et al 2011;Santos-del-Blanco & Climent 2014).…”

Fire‐induced deforestation in drought‐prone Mediterranean forests: drivers and unknowns from leaves to communities

“…]) but invest significant resources into serotinous cones (Santos‐del‐Blanco et al. ). Deeper bark can enhance protection and ensure that sprouters do not suffer top‐kill after crown fires.…”

Evolutionary ecology of fire-adaptive traits in a Mediterranean pine species

“…Male pollen cone clusters per tree ( Figure 16E) when trees were 16 years old were approximated from counts during 15 seconds. This method has been previously used for assessing reproductive traits in different species (Knops and Koenig, 2012;Santos-del-Blanco et al, 2014;Rodriguez-Quilón, 2017). It was chosen after tentative counts by different observers, aiming at combining a reasonable correlation with full male pollen cone clusters and a reasonable speed needed for measuring hundreds of trees with affordable field work schedules.…”

“…Compared with pines typically seen as masting species, P. halepensis interannual variability in reproduction is scarce (the interval between large crops has been shown to be just one year; Tapias et al, 2004), but actually, whether it is a masting species or not has not been studied in depth. Possible mast seeding of this species is highly relevant considering the previously detected costs of reproduction (Santos-del-Blanco et al, 2014).…”