Extinction and recolonization of coastal megafauna following human arrival in New Zealand

Abstract

Extinctions can dramatically reshape biological communities. As a case in point, ancient mass extinction events apparently facilitated dramatic new evolutionary radiations of surviving lineages. However, scientists have yet to fully understand the consequences of more recent biological upheaval, such as the megafaunal extinctions that occurred globally over the past 50 kyr. New Zealand was the world's last large landmass to be colonized by humans, and its exceptional archaeological record documents a vast number of vertebrate extinctions in the immediate aftermath of Polynesian arrival approximately AD 1280. This recently colonized archipelago thus presents an outstanding opportunity to test for rapid biological responses to extinction. Here, we use ancient DNA (aDNA) analysis to show that extinction of an endemic sea lion lineage (Phocarctos spp.) apparently facilitated a subsequent northward range expansion of a previously subantarctic-limited lineage. This finding parallels a similar extinction-replacement event in penguins (Megadyptes spp.). In both cases, an endemic mainland clade was completely eliminated soon after human arrival, and then replaced by a genetically divergent clade from the remote subantarctic region, all within the space of a few centuries. These data suggest that ecological and demographic processes can play a role in constraining lineage distributions, even for highly dispersive species, and highlight the potential for dynamic biological responses to extinction.

Ecological consequences of human niche construction: Examining long-term anthropogenic shaping of global species distributions

“…80 and 92), including the elimination of various species of moa (Dinornis) within two centuries of human colonization (97). Recent studies of sea lion and penguin aDNA show that several New Zealand species once thought to have survived early human impacts were extirpated soon after human arrival and replaced within a few centuries by nonindigenous lineages from the subantarctic region (98).…”

Preliminary assessment of the foraging behaviour and population dynamics of a cryptic population of the endangered New Zealand sea lion

“…However, during the 1800s they were extirpated from the mainland initially by Polynesian hunting and finally due to European sealing until only the subantarctic island populations remained (Collins et al 2014). It is now the subantarctic populations that are significantly declining, with the new threat status being driven by the decline of the species at its main breeding area, Auckland Islands (Fig.…”

Invader or resident? Ancient-DNA reveals rapid species turnover in New Zealand little penguins

“…Bayesian modelling suggests that colonization of E. novaehollandiae occurred within only a few centuries of human arrival in New Zealand and broadly coincided with population declines of the New Zealand endemic penguin E. minor. This newly identified turnover event also highlights that extinction events can potentially facilitate major biogeographic shifts [54], and adds to an emerging body of evidence for dramatic turnover events in response to anthropogenic impacts [15,21,22].…”

“…To avoid sampling an individual multiple times we used only common elements of the same orientation from a single deposit, or sampled bones from different stratigraphic units within a site. Specimens were sampled from sites that have previously yielded aDNA [15,21,22].…”

“…silvereyes, stilts, spoonbills, pukeko) [20]. Additionally, aDNA studies of coastal vertebrates have revealed dramatic biological turnover events, involving wholesale extinction and recolonization [21,22]. In particular, extant mainland yellow-eyed penguin (Megadyptes antipodes) and New Zealand sea lion (Phocarctos hookeri) lineages represent recent arrivals from the Subantartic, following the rapid anthropogenic extinctions of their endemic mainland sister lineages.…”