After the mammoths: The ecological legacy of late Pleistocene megafauna extinctions

Abstract

Our review discusses the ecological consequences of the late Pleistocene extinctions on major aspects of earth systems as well as on the diet, distribution and behavior of surviving mammals. We demonstrate that the late Pleistocene loss of megafauna was pervasive and left legacies detectable within the modern atmosphere, geosphere, hydrosphere and biosphere. Moreover, the ecological roles that extinct and modern megafauna play in the earth system are not replicated by smaller-bodied animals. Our review highlights the importance of integrating a paleontological perspective into modern conservation efforts to develop a more synoptic understanding of ecosystems.

Robust fossil evidence for Proboscidean frugivory and its lasting impact on South American ecosystems

“…A 0.16 mm 2 ocular reticle was employed to quantify microwear features, such as the number of pits (round scars), scratches (elongated scars with parallel sides), gouges (irregular edges and much larger and deeper than large pits), puncture pits (large and very deep pits with crater-like features with regular margins and they appear dark due to low refractivity), cross scratches (oriented perpendicularly to the majority of scratches), and scratch width score (SWS; a score of '0' was given when only fine scratches were present, '1' when there was a mixture of fine and coarse scratches, '2' when coarse scratches were predominantly present, '3' when there was a mixture of coarse and hyper-coarse scratches, and four '4' when the surface also had hyper-coarse scratches). The mean numbers of scratches and pits allow us to categorize dietary habits as browsers (i.e., eating woody and non-woody dicotyledonous plants), grazers (i.e., eating grass), or mixed feeders by comparing the data to known dietary habits of extant ungulates, including the three extant species of elephants 39,40 .…”

“…Fruit rinds in some dicotyledonous plants produce large phytoliths or a high number of phytoliths that are related to the presence of puncture pits in large, fruit browsing mammals 37,38 . Thus, the dental evidence distinguishes these gomphotheres from other leaf-browsing herbivores, linking their diet more closely to fruit and seed ingestion 39,40 .…”

The late-Quaternary megafauna extinctions: Patterns, causes, ecological consequences and implications for ecosystem management in the Anthropocene

“…Current megafauna-poor ecosystems are ecologically novel relative to evolutionary baselines since the majority of modern taxa (e.g., plants, invertebrates) originated and evolved with diverse, abundant large-mammal assemblages (e.g., Martin, 1967;Donlan et al, 2006;Fløjgaard et al, 2022;Figure 4). Since large mammals often have disproportionate impacts on ecosystem structure and processes Enquist et al, 2020;Pringle et al, 2023), the loss of megafauna likely has had strong consequences for many ecosystems (Johnson, 2009;Malhi et al, 2022) and has led to major shifts in biotic community assembly (Carotenuto et al, 2016;Lyons et al, 2016;Tóth et al, 2019;Smith et al, 2023). Importantly, the effects of large mammals cannot be fully compensated for by smaller species (e.g., Lundgren et al, 2024;Trepel et al, 2024) and as such, the changes in impact are expected to have been amplified by the bias in extinctions toward the largest megafauna species (Smith et al, 2018; Figure 1).…”

“…In this section, we evaluate how megafauna affected and continue to affect ecosystem and community processes, drawing on direct evidence from both the past and from contemporary ecosystems. In doing so, we discuss the known and likely ecological consequences of the late-Quaternary megafauna extinctions, with the evidence together indicating that strong losses of large-bodied animals constitute a fundamental re-shaping of terrestrial ecosystem structure and functioning worldwide (Figure 5; see also Smith et al, 2023). The processes by which megafauna affect ecosystems can be grouped within three broad categories: (1) trophic processes that enforce a top-down control on lower trophic levels and ecosystem processes, (2) physical engineering of the abiotic and biotic environment and processes, and (3) the transportation of energy and matter, including nutrients, plant seeds, and smaller organisms.…”

“…Carcasses can therefore generate distinct local nutrient hotspots, with impacts on ecological processes such as plant productivity (Towne, 2000) and carrionassociated species (van Klink et al, 2020). These smaller-scale patterns and processes have the potential to translate to larger scales and affect, for example, the climate system, but this remains poorly understood (Malhi et al, 2016;Pringle et al, 2023;Smith et al, 2023).…”