TAG: GS 3: ECOLOGY AND ENVIRONMENT
THE CONTEXT: The wandering albatross, the world’s largest flying bird, faces a significant threat to its existence, with climate change posing risks to its nesting sites.
EXPLANATION:
- Marion and Prince Edward Islands, situated in the vast Southern Ocean, support about half of the world’s wandering albatross breeding population.
- A recent study delves into the environmental variables affecting the choice of nesting sites and the potential impact of climate change on these oceanic nomads.
Wandering Albatross: Oceanic Nomads
- They belong to the family “Diomedeidae”, are large seabirds.
- The Wandering Albatross have the longest wingspans (195 to 335cm) of any extant birds.
- Albatrosses are ‘carnivores’ in their food choice.
- IUCN status of Wandering Albatross – Vulnerable.
- The wandering albatross spends most of its 60-year lifespan at sea, returning to land to breed approximately every two years.
- The Southern Ocean, between the latitude of 60 degrees south and Antarctica, serves as their playground.
- Marion and Prince Edward Islands, being some of the only land masses in the Southern Ocean, play a crucial role in supporting about half of the global wandering albatross breeding population.
Study on Nest Site Selection
- A study conducted in 2021 aimed to understand the environmental variables influencing the wandering albatross’s choice of nest sites on Marion Island.
- Elevation emerged as the most crucial variable, with albatrosses showing a preference for lower (warmer) sites and coastal vegetation.
- However, these preferences raise concerns about the potential impact of climate change on nesting sites.
Variables Influencing Nest Site Selection
- The study considered various factors, including elevation, terrain ruggedness, slope, distance to the coast, vegetation type, wind speed, wind turbulence, and underlying geology.
- Elevation was identified as the most important variable, influencing the proximity to the coast, vegetation type, and suitability for nesting.
Climate Change Risks to Nesting Sites
- Marion Island, of volcanic origin, presents a challenging terrain with sharp rocks and boggy areas.
- The study points out that changing climates may jeopardize the delicate balance observed in the wandering albatross’s choice of nesting sites.
- Human-driven changes affecting temperature, rainfall, and wind speeds could lead to shifts in vegetation and other species distributions, impacting the availability of suitable nesting areas.
Impact of Climate Change on Marion Island
- Marion Island has experienced temperature increases, precipitation decreases, and changes in cloud cover and sunshine hours over the past decades.
- These alterations, driven by climate change, have already affected the island’s ecosystem.
- Shifts in vegetation patterns and increased wind speeds in the Southern Ocean further contribute to the complexity of the challenges faced by the wandering albatross.
Shrinking Suitable Nesting Areas
- If nesting sites shift to higher elevations due to temperature increases, some areas become unsuitable due to changes in vegetation or wind speeds.
- The study warns that this could lead to a considerable reduction in the suitable nesting area on Marion Island, posing a significant threat to the wandering albatross population.
Conclusion
- The wandering albatross, facing risks such as bycatch from longline fishing trawlers in the open ocean, now confronts an additional threat—climate change affecting its nesting sites.
- The study underscores the urgent need for conservation efforts, considering the delicate balance between environmental variables and the potential impact of climate change on the availability of suitable nesting areas for these majestic birds.