The life history of franciscana dolphins

Abstract

Life history concerns how organisms grow, reproduce and survive (Stearns,1992). From the classical optimization approach, a species´ life history isshaped by the interaction of extrinsic and intrinsic factors (Roff, 1992;Stearns, 2000). Extrinsic factors can be exemplified by the ecologicalimpacts on growth, reproduction, and survival (for example, how environmentshapes reproductive seasonality), while intrinsic factors are thetradeoffs among life-history traits and lineage-specific constraints (whyoffspring size is fixed at 1 in cetaceans). When describing the life historytraits of a species, its constraints, flexibilities, and variation, the outcome ofseveral evolutionary and ecological processes can be uncovered.Understanding life traits that shape the population dynamics and variationin the demography of threatened species is critical for their conservation.In a broader spectrum, it is the framework to assess how a speciescan respond to stressors, to predict the consequences of human-relatedimpacts, and to guide decision-making processes (e.g., Frederiksen et al.,2014; Wade, 1998). The long-term monitoring of certain reproductiveparameters that are subject to density-dependent effects (e.g., age at sexualmaturity (ASM)) may also provide indirect clues about population trajectoryrelative to resources availability (Perrin and Reilly, 1984). Moreover,it has been demonstrated that life-history traits also have the potential forpredicting species vulnerability to climate change in mammals (Jacksonet al., 2021).