Survival of rockhopper penguins in times of global climate change

Abstract

1. Anthropogenic changes in the marine environment and global climate change have led to population declines in several seabird species worldwide. Rockhopper penguins (Eudyptes chrysocome and Eudyptes moseleyi) have experienced a dramatic population decline, potentially linked to increasing sea surface temperatures (SST). Among Southern Ocean diving seabirds, rockhopper penguins typically occupy a low trophic level, and might therefore be expected to mirror climate-driven bottom-up changes to the food web sensitively and on a short time scale.2. Using passive integrated transponders, survival rates of adults in a colony of southern rockhopper penguins (E. chrysocome) on the Falkland Islands were monitored over five consecutive years. Mean annual survival rates were in the range 84 to 96%.3. These values are high compared with other crested penguin species and reflect the generally good conditions during the study period, when low SST prevailed. However, survival rates were lower in 2010, corresponding to very cold conditions. Curve fits showed a best-fit quadratic relationship between average SST anomaly and survival rates for the present data, as well as for a data set including two additional years from a different study at Staten Island.4. Results of this study suggest that rockhopper penguins survive best at SSTs that are lower than the average of the last four decades. In accordance with previously observed rockhopper penguin population declines, the present data suggest that rockhopper penguins are highly sensitive to changes in SST and their effects on the food web, a worrying perspective in times of global climate change. It seems likely that these changes could, in the long term, also affect population trends of other seabird species with similar ecological preferences.5. The most promising conservation approach should aim at enhancing ecosystem resilience, mainly by reducing industrial fishing and oil exploitation. This would allow the currently over-exploited fish and squid stocks to recover, offering larger food resources to seabirds and other vertebrate species.

Higher trophic level prey does not represent a higher quality diet in a threatened seabird: implications for relating population dynamics to diet shifts inferred from stable isotopes

“…The potential negative effects of warm pre-laying SST and exceptionally low over-winter SST on subsequent ERP diet quality suggest a quadratic relationship between SST and diet quality. Similarly, Dehnhard et al (2013) found a quadratic relationship between adult survival of SRP in the southwest Atlantic and SST in a 3-month period overlapping moult. Décima et al (2013) found that an inter-annual increase in SST of c.3 °C was associated with an increase of c.2 ‰ in the baseline δ 15 N values of zooplankton in the California Current Ecosystem.…”

Plasticity in the foraging behavior of male Southern Rockhopper Penguins (Eudyptes chrysocome) during incubation in the Falkland/Malvinas Islands

“…The same phenomenon, to a lesser extent, has been observed in SRP during the chick-rearing period (Dehnhard et al 2016). Furthermore, it could be shown that lower SST increased not only the likelihood of SRP individual survival over the winter months (Raya Rey et al 2007;Dehnhard et al 2013) but also individual body mass at the onset of the reproduction period (Dehnhard et al 2015a). In turn, the latter resulted in earlier egg-laying dates with increased clutch masses (Dehnhard et al 2015b) and an overall higher breeding success (Crawford et al 2008).…”

“…Thus, it can be expected that their preferred foraging areas are also influenced by the prevailing oceanographic conditions . Studies have shown a link between SST and overwintering survival of SRP at both, the Falklands/Malvinas archipelago and Staten Island (Raya Rey et al 2007;Dehnhard et al 2013). In particular, extreme shifts in SST had negative effects on the survival of adults at both sites.…”

Significant decline of endangered Antipodes Island penguins: Is extreme weather an additional impact?

“…The decline that was occurring for the rockhopper penguins at the Antipodes Islands appears to have lessened and possibly halted, as is the case with other eastern rockhopper populations (Baylis, Wolfaardt, Crofts, Pistorius, & Ratcliffe, ; Dehnhard et al, ; Kirkwood et al, ; Morrison et al, ; Oehler et al, ). The widespread and largely simultaneous declines of rockhopper penguin populations throughout their range were thought to be the result of a single shared cause.…”

“…Climate change has been predicted and observed to significantly alter the world's environment and impact all aspects of the life cycle of marine species (life history traits, phenology, movement, Solomon et al, ). These changes are known to affect penguin population parameters and size (Ainley et al, ; Ainley & Blight, ; Dehnhard et al, ; Demongin, Poisbleau, Strange, & Quillfeldt, ; Morrison, Battley, Sagar, & Thompson, ; Parmesan, ; Parmesan & Yohe, ; Trathan et al, ; Walther et al, ). Climate change is altering weather patterns around the globe, including increasing the frequency and severity of storms, significantly increasing precipitation in some areas, bringing flooding and landslides (Coumou & Rahmstorf, ).…”