Climate change a killer for fynbos birds

A new study at the University of Cape Town shows that birds are feeling the heat – and a lot more – from changes in climate.

A dozen species in the Western Cape are declining because of changing conditions, according to the study by scientists from the Percy Fitzpatrick Institute at UCT in collaboration with the Centre for African Conservation Ecology at the Nelson Mandela Metropolitan University.

The study looked at 12 fynbos bird species and compared the information with data captured 15 years prior.

Changes in climate were assessed for the same period and a decline was noted across all species.

Several factors resulting from man-made conditions are pushing them out of their habitats. Heat is one of them, but shifting patterns in fire and rainfall are also proving detrimental.

The study, which will be published in the Oxford University Press journal Conservation Physiology next month, includes some well-known species such as the malachite sunbird and the familiar chat.

Lead researcher Susie Cunningham said the findings could inform plans for better conservation strategies.

“Fynbos birds are particularly important in this regard because they live in an area that has been extremely stable, climatologically speaking, for a very long time. So changes in climate are not something they are used to. Furthermore, six of the species we studied are endemic to the fynbos, so if we lose them from this biome, we lose them altogether.”

A key aspect of the study is a comparison of climate and bird population data with the “thermal tolerance” of each bird species. Researchers assessed to what extent birds can cope with changing temperature, and whether this is the primary indicator of changes in bird abundance.

Cunningham said the overall findings suggested scientists should not jump to conclusions about bird physiology when assessing the effects of climate change.

“The main findings are that physiology, though often considered the ultimate factor limiting species distributions, may not be the factor responsible for warming-related declines in most Fynbos birds.”

Some of the key findings include:

• All 12 of the study species, which included both endemic and non-endemic fynbos birds, show range declines over the 15-year period
• Bird species living in naturally warmer areas are generally faring better than those in cooler areas, but species experiencing greatest warming within their ranges are declining fastest. These patterns are strikingly similar to patterns observed in the Northern Hemisphere, suggesting warm-adapted birds are faring better under climate change, globally.
• Endemic bird species, which typically favour cooler habitats, appear to be more vulnerable to climate change than non-endemic species
• Highest rates of climate warming were recorded in inland (mountainous) areas, whereas some coastal areas have cooled.
• Eight of the 12 study species (and five of six Fynbos endemics) show declines in reporting rate or local extinction in more than half of their habitat range.