Wattle we do to help the penguins!?

Author: Jane Weichert

The effect of anthropogenic activity on gentoo penguins

Growing up we all heard the slogan “save the polar bears,” as it was an amazing way to spark children's curiosity in climate change; these large mysterious creatures whose homes were falling apart because of anthropogenic, or human, activities. Well, polar bears are not the only warm and fuzzy animals who are feeling the effects of climate change. Pygoscelis papua, also known as gentoo penguins, live on the Antarctic Peninsula and its surrounding islands and while their population is actually growing, they are experiencing the damaging effects of tourism everyday [1]. 

How is the gentoo population both growing and shrinking?

As temperatures continue to rise in the Antarctic Peninsula, areas that were historically covered in ice are beginning to show the land beneath them. While this disruption hurts many populations that rely on the icey-cover to survive, gentoo penguins actually prefer ice-free areas including coastal plains, sheltered valleys, and cliffs [3]. Thus, as more habitat becomes available for the gentoo penguins their populations expand--who doesn’t love a new hangout spot!

However, not all is well. Many of the original colonies of gentoo penguins are heavily affected by tourism, having a negative impact on their daily lives. Gentoo penguins form life-long bonds with their partners and work together to build their nests and raise their chicks (more information on gentoo penguin couples and other background information can be found here). Penguin couples can become distracted or irritated by large crowds and loud sounds, the effects of which can be seen in their mating and breeding successes. In a highly visited population on Goudier Island, Port Lockroy, there has been a 1.4% decrease in breeding pairs and 3.8% decrease in chicks raised per year [1]. The overall decrease in mating and breeding success in highly visited colonies leads to a significant decrease in the number of individuals in these populations. These trends are seen in many of the largely visited populations around the Antarctic Peninsula.

A growing population is not always a good thing.

The overall population of gentoo penguins has grown by 11% since 2013 [5]. Continuing to expand across the Antarctic Peninsula, the two edge colonies, meaning the individuals that live furthest apart, have less and less contact with each other. Because of this distance they are unable to breed regularly, decreasing the population's gene flow. Gene flow is the ability of an individual, or its genetic material, to migrate from one population to another. If there is too little gene flow between populations, the populations can actually morph into two separate populations. 

There is evidence of the two edge populations becoming genetically separate. While they may look alike, there are key genetic differences between the populations. To read more about the separation of populations click here [6]. As the population becomes more and more separate, threats of infertile chicks increases, because their mother and father may no longer be genetically compatible. This new pattern could lead to a decrease in population size, because chicks will still be laid, however the parents will not know if it is fertile or not until it has grown.

There is still a lot of hope for the gentoo penguins!

The Committee for Environmental Protection and the International Association of Antarctica Tour Operators have set regulations on the amount of tourism in Antarctica in order to protect the wildlife from increased stress levels [7]. Many researchers have focused on comparing anthropogenically induced stress levels of gentoo penguin populations to the typical amount of stress experienced by non-visited populations. The research shows there are no major effects of stress on the physiology, or normal body functions, of gentoo penguins [7].

Future research…

While there has been some research done about microplastics found in gentoo penguin diets, little is known about how this affects their physiology [8]. Researchers should focus on how these microplastics are entering their bodies, through their food sources or through direct ingestion, and how these microplastics affect them.

Other research should focus on the possible effects of genetic mutations on the physiology of gentoo penguins. As the edge populations become genetically separate, how will the colonies evolve to better suit the habitat they are expanding into.

Citations

1. M. J. Dunn et al., A long-term study of gentoo penguin (Pygoscelis papua) population trends at a major Antarctic tourist site, Goudier Island, Port Lockroy. Biodiversity and Conservation. 28, 37–53 (2018), doi:10.1007/s10531-018-1635-6. 
2. Gentoo Penguin. Wild Republic (available at https://www.wildrepublic.com/product/gentoo-penguin/). 
3. Gentoo Penguin: National Geographic. Animals (available at https://www.nationalgeographic.com/animals/birds/facts/gentoo-penguin).
4. Contrary to the fears of some, penguins and people do mix. The Economist (available at https://www.economist.com/science-and-technology/2019/07/11/contrary-to-the-fears-of-some-penguins-and-people-do-mix). 
5. R. Herman et al., Update on the global abundance and distribution of breeding Gentoo Penguins (Pygoscelis papua). Polar Biology. 43, 1947–1956 (2020), doi:10.1007/s00300-020-02759-3.
6. L. R. Pertierra et al., Cryptic speciation in gentoo penguins is driven by geographic isolation and regional marine conditions: Unforeseen vulnerabilities to global change. Diversity and Distributions. 26, 958–975 (2020), doi:10.1111/ddi.13072.
7. M. A. Lynch, et al., Tourism and stress hormone measures in Gentoo Penguins on the Antarctic Peninsula. Polar Biology. 42, 1299–1306 (2019), doi:10.1007/s00300-019-02518-z.
8. F. Bessa et al., Microplastics in gentoo penguins from the Antarctic region. Scientific Reports. 9 (2019), doi:10.1038/s41598-019-50621-2.

 Image Credits

"Gentoo Penguins" by D-Stanley is licensed under CC BY 2.0 To view the terms, visit https://search.creativecommons.org/photos/abbdc733-b33d-4993-9016-3bb2e5b8d343

"Gentoo Penguin with chick" by Liam Quinn is licensed under CC BY-SA 2.0 To view the terms, visit https://search.creativecommons.org/photos/672cefa2-1bc8-426d-a5e0-aa101e08f19d