Longevity, body dimension and reproductive mode drive differences in aquatic versus terrestrial life‐history strategies

1. Aquatic and terrestrial environments display stark differences in key environmental factors and phylogenetic composition but their consequences for the evolution of species' life‐history strategies remain poorly understood.

2. Here, we examine whether and how life‐history strategies vary between terrestrial and aquatic species. We use demographic information for 685 terrestrial and 122 aquatic animal and plant species to estimate key life‐history traits. We then use phylogenetically corrected least squares regression to explore potential differences in trade‐offs between life‐history traits between both environments. We contrast life‐history strategies of aquatic versus terrestrial species in a principal component analysis while accounting for body dimensions and phylogenetic relationships.

3. Our results show that the same trade‐offs structure terrestrial and aquatic life histories, resulting in two dominant axes of variation that describe species' pace of life and reproductive strategies. Terrestrial plants display a large diversity of strategies, including the longest‐lived species in this study. Aquatic animals exhibit higher reproductive frequency than terrestrial animals. When correcting for body size, mobile and sessile terrestrial organisms show slower paces of life than aquatic ones.

4. Aquatic and terrestrial species are ruled by the same life‐history trade‐offs, but have evolved different strategies, likely due to distinct environmental selective pressures. Such contrasting life‐history strategies have important consequences for the conservation and management of aquatic and terrestrial species.