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Dryad

Avoiding growing pains in reproductive trait databases: the curse of dimensionality

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Sep 07, 2022 version files 9.76 MB

Abstract

Aim: Reproductive output features prominently in many trait databases, but the metrics describing it vary and are often untethered to temporal- and volumetric-dimensions (e.g., fecundity-per-bout). Using such ambiguous reproductive measures to make broadscale comparisons across taxonomic groups will only be meaningful if they show a 1:1 relationship with a reproductive measure that explicitly includes both a volumetric and temporal component (i.e., reproductive mass-per-year). We sought to map the prevalence of ambiguous and explicit reproductive measures across taxa, and explore their relationships with one another to determine the cross-compatibility and utility of reproductive metrics in trait databases.

Location: Global.

Time period: 1990-2021.

Major taxa studied: We searched for reproductive measures across all Metazoa, and identified 19,785 Chordata species, along with 440 species of Arthropoda, Cnidaria, or Mollusca.

Methods: We included 37 databases from which we summarised the commonality of reproductive metrics across taxonomic groups. We also quantified scaling relationships between ambiguous reproductive traits (fecundity-per-bout, fecundity-per-year and reproductive mass-per-bout) and an explicit measure (reproductive mass per-year) to assess their cross-compatibility.

Results: Most species were missing at least one temporal or volumetric dimension of reproductive output, such that reproductive mass-per-year could be reconstructed for only 4,786 vertebrate species. Ambiguous reproductive measures were poor predictors of reproductive mass-per-year – in no instance did these measures scale at 1:1.

Main Conclusions: Ambiguous measures systematically misestimate reproductive mass-per-year. Until more data are collected, we suggest authors use the clade-specific scaling relationships provided here to convert ambiguous reproductive measures to reproductive mass-per-year.