A summary paper focusing on our six main endemic birds of the Fynbos came out in the journal Bird Conservation International earlier this year. I calculated bird densities, population sizes, identified preferred fire successional preference and examined ranges from SABAP2 data. I also used the atlas data to identify trends for the Fynbos birds and a suite of other endemic birds (simply reporting rate changes and range changes).
A bit of a concern is that the group of Fynbos endemic birds is generally the worst off, with Cape Rockjumper and Protea Seedeater fairing particularly badly comparing between atlas projects. While the degree of population change that this really represents is still an item of discussion, it was worthy to note that these changes were well explained by the species tolerance (or intolerance) to warm temperatures as calculated from a physiology project conducted in 2013 by Robyn Milne. In fact, in the absence of any other explanatory variables, climate change (particularly warming) seems to be the best reason for these changes at this time. After all, Mountain Fynbos is little modified by the usual host of problems associated with human land conversion. For Cape Rockjumper in particular, which stresses out at just over 30 degrees (the lowest of 12 species tested), it appears from various angles that range is limited by temperature. With an increase of between 0.5 and 1 degree, this translates to a vertical loss of space of around 100 meters, which isn't a good thing if you're already a species that prefers mountain tops – there is no where left to go, and a temperature increase of 4 degrees will mean there will no more comfortable living space left for this species.
How exactly hotter temperatures may influence behaviour and breeding is now the focus of the research of the Hot Fynbos Birds project team. Krista Oswald is just starting a Masters project on the topic and we're hoping for some good news from this in the next year or two.
The official paper can be downloaded from the publisher website here http://journals.cambridge.org/abstract_S0959270914000537
and a copy is available here http://www.bluehillescape.co.za/Peru/aims.html
The kudos perspectives link: http://goo.gl/zQvkTV
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| Too hot for his own good: A male Cape Rockjumper |
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| Krista Oswald and Kate Beer monitoring Cape Rockjumpers. No easy task! |
I remember seeing rockjumpers when we walked on the Pipe Track, when Camps Bay was home.
ReplyDeleteWould the sea breeze be enough to keep the temperatures down to where the birds could survive?
Hi Di... it is certainly the case that the presence of the ocean stabilises the climate nearby and one does not experience the extreme temperature fluctuations that occur further inland. The Kogelberg is a special case for Rockjumpers where they can occur down to sea level, further inland they are only found higher up the mountains.
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