Behavioural plasticity and population connectivity: Contributors to the establishment of new pinniped breeding colonies

Abstract

1. Understanding the ecological and evolutionary processes that occur during range shift or (re-)colonization is of critical importance for species whose ranges are changing due to human-induced climate change or species such as New Zealand sea lions where their established colonies are significantly declining due to human impacts.2. The mechanisms underlying colonization are poorly understood. Observations are required to determine the processes that change individual's behaviour associated with colonization, but such observations are rare.3. Here, the establishment of a new breeding colony of New Zealand sea lions, Phocarctos hookeri, as they recolonized mainland New Zealand, an area from which they had been absent for 200 years was investigated.4. There are differences in breeding location behaviour and population connectivity between established and establishing colonies of New Zealand sea lions. The recolonizing population is more dispersed with breeding locations that change annually and have more connections with other populations compared with established colonies and populations.5. The establishment of a new colony and the greater numbers of resightings between colonies means that for species' management, considerably more public education, habitat management, and protection is needed to ensure the safe return of New Zealand sea lions back on to mainland New Zealand.

Quantifying dispersal between two colonies of northern elephant seals across 17 birth cohorts

“…We demonstrate here that dispersal continues now, even after the range has filled, and elephant seals are thus poised to expand their range further, as they recently have at King Range in northern California [ 35 ]. In other pinnipeds, poor dispersal may be a primary reason for slow recovery [ 11 ]. The fact that elephant seals disperse well appears to be a fortuitous trait in the face of the 19 th century decimation by hunters.…”

“…During 50 years of research in California, we observed dispersal and documented new colonies formed by immigrants [ 7 ], but quantifying dispersal has been difficult, as is often the case in large animals that move long distances [ 8 , 9 ]. Without precise estimates of rates of movement, we do not know whether dispersal continues now that the range is reestablished, and we cannot compare the importance of dispersal in elephant seals to other species [ 10 , 11 ]. Here we fill the gap by quantifying dispersal rate in two directions in 17 consecutive birth cohorts.…”

Quantifying dispersal between two colonies of northern elephant seals across 17 birth cohorts

“…We demonstrated here that dispersal continues now, even after the range has filled, and elephant seals are thus poised to expand their range further, as they recently have at King Range in northern California (Goley & Levy, 2021). In other pinnipeds, poor dispersal may be a primary reason for slow recovery (Chilvers & Dobbins, 2021). The fact that elephant seals disperse well appears to be a fortuitous trait in the face of the 19 th century decimation by hunters.…”

“…During 50 years of research in California, we observed dispersal and documented new colonies formed by immigrants (Le Boeuf et al ., 2011), but quantifying dispersal has been difficult, as is often the case in large animals that move long distances (McCaslin et al ., 2020; Tittler et al ., 2009). Without precise estimates of rates of movement, we do not know whether dispersal continues now that the range is reestablished, and we cannot compare the importance of dispersal in elephant seals to other species (Bowne & Bowers, 2004; Chilvers & Dobbins, 2021). Here we fill the gap by quantifying dispersal rate in two directions in 17 consecutive birth cohorts.…”