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Andes Mountain hummingbirds might lose habitat, risk extinction, as climate warms

The Andes Mountains are home to diverse forest ecosystems including rainforests and cloud forests. Hummingbirds in this region are vulnerable to climate change.

As the climate warms in this century, forest ecosystems in the Andes Mountains will change and these changes could have significant negative impacts on flora and fauna, in particular Neotropical hummingbirds, according to a recent study.

Andes Mountains cloud forest.

The Andes Mountains are the world’s longest continental mountain range and stretch for over 7,000 kilometers (4,350 miles) down the western edge of South America. The Andes Mountains are home to diverse forest ecosystems including rainforests and cloud forests.

A team of scientists from the University of California and the Smithsonian Tropical Research Institute recently embarked on a study to investigate how climate change may alter Andes forest ecosystems and impact the geographic distribution of five Neotropical hummingbird species.

According to the paper published in the April 2011 issue of Global Change Biology:

The Tropical Andes represents a critically endangered hotspot of biological diversity, and a major region expected to undergo dramatically altered climate due to current global warming.

The scientists modeled changes in temperature and precipitation for two different climate-change scenarios in the year 2080. Under the conservative climate change scenario, temperatures in the Andes forests were projected to increase by 1.8 to 2.6 degrees Celsius and under the extreme climate change scenario, temperatures in the Andes forests were projected to increase by 2.5 to 5.3 degrees Celsius. The scientists then linked these projected climate changes to alterations in forest habitat for Neotropical hummingbirds.

The scientists discovered that climate change may substantially shift hummingbird habit upwards in elevation by about 300 to 700 meters, which would result in less suitable forest habit available for the bird species.

The authors conclude:

Overall, the physiological impact of elevational shifts of < 1000 meters on flight performance and, hence, survivorship, is likely to be small. [ … ]. It is likely that other factors such as interspecific competition and changes in floristic composition will present greater challenges. In particular, habitat losses due to climate change, on the order of 13–40% relative to current Andean hummingbird range sizes as suggested by our study, and ongoing land use change may represent the most severe factor towards enhanced extinction risk.

The scientific research was funded by the National Science Foundation and Earthwatch Institute.

In addition to Neotropical hummingbirds, other species that live in sensitive mountain ecosystems such as the American pika and the Golden Bower bird are under pressure to either adapt or find new suitable habitat at higher elevations as the climate changes.

Deanna Conners

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