Durban – For many environmentalists, the only good alien is a dead alien. But some local bird lovers have put the cat among the pigeons by calling for special protection of certain invasive alien trees on the basis that they are crucial to the survival of eagles and other birds of prey.
Writing in the latest edition of Environment magazine, John Wesson of the Wildlife and Environment Society and Leon Scholtz of the SA Nurserymans Association said the wholesale clearance of invasive alien trees could have unintended consequences for several species of raptors.
They said fish eagles, crowned eagles, snake eagles, Wahlberg’s eagles, falcons and kestrels used eucalyptus (gum), pine trees and grey poplars for roosting and nesting.
They complained that the clearance of alien invasive plants by groups such as Working for Water often led to the felling and ring-barking of “ancient breeding sites” for birds.
Wesson and Scholtz said although there were guidelines to protect raptor nests during alien tree clearing programmes, these guidelines were not always followed.
“In many cases, the only trees targeted are the ones that can be used for firewood or planking, but other trees like Yellow Bells... are left to flourish.
“We urge all the role-players to urgently look at ways to stop this major negative impact on our wildlife.”
Writing in the same magazine issue, Birdlife South Africa chief Mark Anderson said nearly 30% of the country’s diurnal raptors (about 18 species) nested in alien trees
“The conservation status of these raptors is likely to be negatively affected by the systematic removal of alien trees (particularly eucalyptus, pine and poplars).”
However, two prominent Durban environmentalists beg to differ.
Wally Menne, an indigenous plant specialist and co-ordinator of the Timberwatch coalition, said he was amused to hear about alien gum tree stands being referred to as “ancient breeding sites” deserving of protection or natural heritage status.
“We should be ashamed that these alien trees were planted in the first place out of pure ignorance. Our forefathers have altered the whole ecology by introducing alien trees.”
In his view, all aliens should be removed – except if particular trees hosted an active raptor or bird nest.
Kloof Conservancy chairman Paolo Candotti said the main reason why raptors (and others) nested in invasive alien trees was because indigenous forests had been destroyed.
“My approach is relatively simple: if they are invasive aliens then they must ultimately go.
“I am not advocating the destruction of known nest sites – if there is a nest then it will be necessary to leave a stand of invasive aliens until such time as alternative options are available for the birds – and that could be a long time.”
But it was “ludicrous” to say that invasive aliens in general should not be cleared because it might affect raptors or because they were part of the country’s “heritage”.
“My limited experience is that where there is an indigenous forest the raptors live quite happily. Krantzkloof Nature Reserve is a case in point.
“Outside of the reserve there are raptor nests in gum trees simply because they don’t have anything else to nest in. Let’s get the focus on re-establishing indigenous trees rather than trying to protect species that are destroying our biodiversity,” said Candotti.
“I am disappointed with the articles particularly as they come from very responsible people… Have any of these people given any thought to the wetlands that some of these species have destroyed, the amphibian species that disappeared with the wetlands, the antelope species that can no longer feed in blue gum plantations?”
The Mercury