||THREATS TO THE BRENTON BLUE
(and other butterflies in the Knysna area)
The greatest threat to butterflies is loss of habitat, due to encroachment by diverse developments,
such as housing and golf courses. As the human population continues to grow, more and more natural land
is irreplaceably destroyed. All living creatures need space to survive - unless we commit to preserving
space for them, many animals will disappear forever. This would be a tragic loss for future generations.
Much of the development which threatens butterfly species today involves non-essential construction of
luxury homes, hotels and golf courses. As the current guardians of biodiversity, we need to
seriously consider whether such developments are really worth the permanent loss of species.
Orachrysops niobe (the Brenton Blue) -
Status: CRITICALLY ENDANGERED
Threats: The only known colony of the Brenton Blue is the Brenton
Blue Butterfly Reserve, in Brenton-on-Sea, near Knysna in the Western Cape. Small populations, like
this one, will always be at great risk of stochastic (chance) events, such as severe drought or an
uncontrolled fire. The reserve needs to be carefully monitored and managed, so that the health and
availability of the butterfly's food plant, Indigofera erecta, is sustained. In addition, viable
colonies of the ant species, Camponotus baynei (see Natural History),
to which the Brenton Blue's lifecycle is strongly linked, need to be present.
These ant colonies may be threatened by invasive (alien) ant species or vegetation changes. Furthermore,
small breeding populations
of any species of animal are at risk of loss of genetic diversity, due to inbreeding effects. If any
genetic deformities are present, these will persist in future generations and may lead to deterioration
of the species.
OTHER BUTTERFLIES IN THE KNYSNA REGION
Thestor brachycerus brachycerus -
Status: CRITICALLY ENDANGERED
Threats: Strong colonies close to the Eastern Heads were destroyed by building activities, the
most recent being lost in 1996. One of the colonies has been eliminated by the change to sheep farming
in the early 2000s. Another was lost by the building of the access road to the Sparrebosch (now
Golf Estate in 1998. Another has been weakened by overgrazing with sheep, and was further threatened by
the Fernwood development before the developers were persuaded to put aside an area for the butterfly,
but it has not been seen for two years. A further colony was destroyed during the building of the golf
course. Only a few colonies remain: one exists on Pezula and
the owners of Pezula have undertaken not
to disturb it. Fortunately, in December 2004, an additional, small colony was discovered during the
scoping study for a development proposed in the south west corner of Pezula and there is hope that this one can be protected. The recent creation of the
Knysna Coastal Conservancy by Pezula has improved the
potential for saving this butterfly.
Aloeides thyra orientis -
Threats: Encroachment of alien vegetation. Construction of houses or roads (presently
unlikely, but may happen in the future).
Chrysoritis thysbe mithras -
Threats: Encroachment of alien vegetation. The recent establishment of the Western Heads
Conservancy holds promise for improved landscape management.