Punctuated ecological equilibrium in mammal communities over evolutionary time scales

Paleontology for conservation Human activities are leading to broad species and system declines. Prevention of such declines has led us to focus on either protection for species or protection for ecosystem function. Looking at past patterns of species and system change can help to inform our understanding of the long-term impacts of these strategies. Blanco et al. studied mammals from the last 21 million years on the Iberian Peninsula, finding long periods of functional stasis, even in the face of taxonomic variability (see the Perspective by Roopnarine and Banker). Functional ecosystems were more resistant to ecosystem collapse. Science, this issue p. 300; see also p. 237 Functional richness in past mammal communities increased ecosystem resilience. The study of deep-time ecological dynamics has the ability to inform conservation decisions by anticipating the behavior of ecosystems millions of years into the future. Using network analysis and an exceptional fossil dataset spanning the past 21 million years, we show that mammalian ecological assemblages undergo long periods of functional stasis, notwithstanding high taxonomic volatility due to dispersal, speciation, and extinction. Higher functional richness and diversity promoted the persistence of functional faunas despite species extinction risk being indistinguishable among these different faunas. These findings, and the large mismatch between functional and taxonomic successions, indicate that although safeguarding functional diversity may or may not minimize species losses, it would certainly enhance the persistence of ecosystem functioning in the face of future disturbances.