| dc.description.abstract | Extinction risk is inversely associated with maximum per capita population growth rate (r(max)).
However, this parameter is not known for most threatened species, underscoring the value in
identifying correlates of r(max) that, in the absence of demographic data, would indirectly allow
one to identify species and populations at elevated risk of extinction and their associated recovery
potential. We undertook a comparative life-history analysis of 199 species from three taxonomic
classes: Chondrichthyes (e. g., sharks; n = 82), Actinopterygii (teleost or bony fishes; n 47), and
Mammalia (n 70, including 16 marine species). Median r(max) was highest for (and similar between)
terrestrial mammals (0.71) and teleosts (0.43), significantly lower among chondrichthyans (0.26),
and lower still in marine mammals (0.07). Age at maturity was the primary (and negative) correlate
of r(max). In contrast, although body size was negatively correlated with r(max) in chondrichthyans
and mammals, evidence of an association in teleosts was equivocal, and fecundity was not related to
r(max) in fishes, despite recurring assertions to the contrary. Our analyses suggest that age at
maturity can serve as a universal predictor of extinction risk in fishes and mammals when r(max)
itself is unknown. Moreover, in contrast to what is generally expected, the recovery potential of
teleost fishes does not differ from that of terrestrial mammals. Our findings are supportive of the
application of extinction-risk criteria that are based on generation time and that are independent
of taxonomic affinity. | en_US |
