Grassroots September 2016, Vol. 16, No. 3 | Page 8
News
How South Africa’s second most invasive tree can be managed
better
Ross Shackleton
Stellenbosch University, Conservation and invasion Biology
http://theconversation.com/how-south-africas-second-most-invasive-tree-can-be-managed-better62723
M
any plants have been moved around the
world for many reasons – for example
for ornamental purposes, forestry and
agriculture. A small proportion have become
invasive, spreading beyond the areas in which they
were initially planted. In some cases this has
negatively affected humans and the environment.
to come up with solutions about how to overcome
these problems.
The key barriers identified were:
One such tree genus, Prosopis, or mesquite,
originally from the Americas, has been introduced
to more than 100 countries. It was introduced into
the arid parts of South Africa to aid farmers and
local communities with fodder production, provide
shade for livestock and produce firewood.
It has now invaded large parts of the country and
has become the second most widespread invasive
tree after Australian acacias. It has had a negative
impact on biodiversity, livestock production, land
value, human health, infrastructure and water
supply. These are all crucial factors for the
economy and for local people’s livelihoods.
The negative effects of these invasions have led
to the initiation of programmes to manage them
across the world. In South Africa the Working for
Water programme drives management on state and
private land along with input from private
landowners. Without active management these
invasive plants would become more widespread
and their impact on people and the environment
would be more pronounced.
Reducing the impact
Management initiatives, such as Working for
Water, aim to reduce the impact and spread of
invasive plants. In South Africa the initiative also
aims to create jobs and drive rural development.
We recently conducted a study to assess the
barriers that impede the effective management of
widespread Prosopis invasion. More than 100
barriers were identified in the study, which tried to
identify the problems that hinder current
management operations. The results could be used
Grassroots
September 2016
Using versus removing the tree and
control options. Some parties wanted to
continue using Prosopis for fodder and
fuelwood and did not want them removed.
Others pointed to the serious negative
impact they have. There was also
controversy
about
labour-intensive
management, which is time consuming
and makes progress slow. Mechanical and
biological
control
approaches
are
obviously faster but employ fewer people.
The ecology of the species. It is hard to
control because it grows very fast and
spreads rapidly. It is also capable of
regrowing from cut stumps if herbicide is
not applied correctly.
Poor planning and prioritisation. Often no
systematic control strategy is followed.
Coordination and cooperation, which is
linked to poor planning, inefficient
management, corruption and lack of
collaboration
between
different
government departments and farmers.
There were differences in how the
importance of some barriers were
perceived. Most farmers – 80% – placed
high importance on a lack of planning and
poor management as important barriers.
Few managers – 20% – regarded these as
important. This reflects different views
about the context in which management
projects operate.
Adaptation responses
1.
Many of the barriers can be overcome and
ways to do this were identified in some
Vol 16 No. 3