Assessing the population trend and threats to New Zealand’s Fiordland crested penguin using counting and demographic modelling approaches

Abstract

The Fiordland crested penguin Eudyptes pachyrhynchus is one of the least studied crested penguin species, with indications the species has a declining population, which would be in line with the historic and contemporary trends for most crested penguins. To determine the current population trend of the Fiordland crested penguin, a number of monitoring programmes using both abundance counts and demographic modelling approaches were carried out between 1990 and 2010 in the northern half of the species' range. A 2.6% ± 0.8% annual decline rate of active nests was detected at 14 monitoring plots, and the number of nests along two coastlines declined annually by 1.2% and 2.6%. Population matrix models using site-specific demographic rates for the species at two South Westland sites indicated contrasting population trends, with one site increasing by 1.6% annually and a second site decreasing at 0.3% annually. Due to concerns about the reproductive parameters used in the model, the trajectory indicated by the nest-chick data was deemed more robust and should be used to inform management. Six potential threats to Fiordland crested penguin were reviewed against the detected population trend and specifically adult survival, but it was determined that there is insufficient understanding about the species, particularly its foraging ecology and effects of fishing and terrestrial predation, to confidently identify the key threats. Therefore, the recommended management action is to address these knowledge gaps.

Happy Feet in a Hostile World? The Future of Penguins Depends on Proactive Management of Current and Expected Threats

“…For example, climate change is a global issue, not influenced by political boundaries, that requires intergovernmental effort at a global scale, whilst limiting coastal development and regulating marine-capture fisheries continues to be a growing challenge as 250 additional humans are born every minute (The World Factbook, 2016). With such pressures, one of the critical challenges facing ecologists is the attribution of cause through analyzing long-term data that describe changes in functional traits (e.g., body condition, foraging activity), vital rates (e.g., survival, fecundity) and population size (Jenouvrier et al, 2018;Otley et al, 2018). Few studies have accounted for the effects of stressors, such as climate change, on the complete life cycle of species, thereby accounting for multiple seasonal and carry-over effects of the stressor (Jenouvrier et al, 2012;Iles and Jenouvrier, 2019).…”

Ancient DNA of crested penguins: Testing for temporal genetic shifts in the world’s most diverse penguin clade

“…Several studies have demonstrated major declines in crested penguins during the late 20th century (Crawford et al, 2009(Crawford et al, , 2010Davis 2013;Morrison et al, 2015;Otley et al, 2018). Taylor (2000) and Otley et al (2018) suggest E. pachyrhynchus populations have declined significantly since this time. Surveys of E. sclateri suggest that populations were stable until 2011, but have subsequently declined by 19% (Hiscock and Chilvers, 2014).…”