Melting barriers to faunal exchange across ocean basins

Abstract

Accelerated loss of sea ice in the Arctic is opening routes connecting the Atlantic and Pacific Oceans for longer periods each year. These changes may increase the ease and frequency with which marine birds and mammals move between the Pacific and Atlantic Ocean basins. Indeed, recent observations of birds and mammals suggest these movements have intensified in recent decades. Reconnection of the Pacific and Atlantic Ocean basins will present both challenges to marine ecosystem conservation and an unprecedented opportunity to examine the ecological and evolutionary consequences of interoceanic faunal exchange in real time. To understand these changes and implement effective conservation of marine ecosystems, we need to further develop modeling efforts to predict the rate of dispersal and consequences of faunal exchange. These predictions can be tested by closely monitoring wildlife dispersal through the Arctic Ocean and using modern methods to explore the ecological and evolutionary consequences of these movements.

Climate change could overturn bird migration: Transarctic flights and high-latitude residency in a sea ice free Arctic

“…Conversely, migration along sea ice edges at the periphery of the Arctic Basin seems much more widespread 28 . Also, radar studies and direct observations demonstrated that several species of seabirds are capable of crossing the Arctic Basin 30,31 as already observed in fishes 32 and marine mammals 31 .…”

“…On a worldwide scale, we speculate that other migratory pathways may be shifted by global change. Notably, there are strong signals that Pacific seabirds may also migrate into the Atlantic via the North Pole 31 . Transcontinental bird migrations currently occur on eight flyways which all run North-South along the Americas, Africa-Eurasia, and Australasia 94 .…”

Climate Change Will Re-draw the Map for Marine Megafauna and the People Who Depend on Them

“…Some bridges will become available due to changing climactic conditions. Reduced Arctic sea ice is allowing access to novel feeding grounds (e.g., bowhead whales, Balaena mysticetus in the Arctic) (McKeon et al, 2016), while thermal isoclines in the ocean create dynamic pathways of oceanic conditions in which fish can survive and move (Briscoe et al, 2017).…”

“…One species' bridge, may be another's barrier. Melting Arctic sea ice allows whales to move between the Atlantic and Pacific oceans (McKeon et al, 2016), but the bears and pinnipeds that depend on that ice for their habitat will find themselves with a diminishing range area and fractured populations.…”

What's hot in conservation biogeography in a changing climate? Going beyond species range dynamics

“…Climate change is expected to cause significant shifts in biogeographical barriers and movement of species. Beyond elevation shifts in mountain ranges, there is mounting evidence that melting of Arctic sea ice will cause dramatic exchanges in birds and mammals (McKeon et al, ), and fish interchanges (Wisz et al, ). This is likely to shape communities and hence conservation prioritization and conservation planning in a rapidly warming climate.…”