Pumas are back in Patagonia and Penguins are paying the price

 Should conservation efforts focus on protecting one iconic species if that protection may harm another, especially in landscapes still recovering from human activity? This question lies at the center of a growing conservation challenge at Monte Leon National Park on Argentina's Patagonian coast.

The situation highlights the complexity of restoring ecosystems that were altered for decades and are now undergoing rapid change.

Pumas Return and Penguins Face a New Threat

After cattle ranching ended in southern Argentina in 1990, pumas (Puma concolor) gradually began reclaiming parts of their historic range. Their return brought them into contact with Magellanic penguins (Spheniscus magellanicus) for the first time in modern history.

The penguins had previously moved from offshore islands to the mainland, taking advantage of the absence of land predators. With few defenses against large carnivores, they became easy prey once pumas arrived. Until recently, however, scientists did not know how much this new interaction was affecting penguin population numbers.

Long Term Monitoring in Monte Leon National Park

Since the park was established in 2004, penguin colonies have been closely observed by researchers from the Centro de Investigaciones de Puerto Deseado of the Universidad Nacional de la Patagonia Austral, working alongside rangers from Monte Leon National Park. Over a four year period (2007-2010), they recorded penguin carcasses linked to puma attacks.

For the latest study, the team partnered with researchers from Oxford University's Wildlife Conservation Research Unit (WildCRU) to analyze the data and assess the long term implications for the colony.

Thousands of Penguins Killed

Using carcass counts, the researchers estimated that more than 7,000 adult penguins were killed during the four year study period. Many of the birds were only partially eaten or not eaten at all, indicating that the killings were not solely for food. This figure represents about 7.6% of the adult population (around 93,000 individuals).

Lead author Melisa Lera, a postgraduate student at WildCRU, Oxford University said: "The number of carcasses showing signs of predation we found in the colony is overwhelming, and the fact that they were left uneaten means pumas were killing more penguins than they required for food. This is consistent with what ecologists describe as 'surplus killing'. It is comparable to what is seen in domestic cats when prey are abundant and/or vulnerable: ease of capture can lead to cats hunting more birds, even when they do not end up actually eating them. We needed to understand if the penguin colony's persistence could be threatened due to this behavior."

Source: ScienceDaily