Environmental Assessment
Volume C-4.1
Slurry Pipeline
Flora
Ambatovy Project
89
January 2006
4.1.6.5 Impact Analysis
Residual Impacts to Exotic and Unwanted Species
During the construction and operation phases it is expected that exotics and
unwanted plant species will invade reclaimed areas and forest edges. Aggressive
control measures will be used to eradicate the species as soon as they are
discovered. Initially, unwanted species may be difficult to recognize as
troublesome since they may be native species. In certain cases, a species may
become prominent in an area, which may be part of a normal successional
pathway. In other cases, a species may simply choke out others, reducing
diversity and limiting succession.
Control measures planned cannot eliminate unwanted species totally, and
therefore, a low negative environmental consequence is predicted (Table 4.1-5).
Table 4.1-5 Residual Impact Classification for Exotic and Unwanted Plant
Species
Component
Direction
Magnitude
Geographic
Extent
Duration
Reversibility Frequency
Environmental
Consequence
exotic or
unwanted
plant species
negative
low
local
medium-
term
reversible
medium
low
During construction, operation and closure phases, control measures will be used
to rid exotic and unwanted (weeds) species along the pipeline route and along the
edges of primary forests that the pipeline passes through.
Prediction Confidence
The general behavior of invasive unwanted species is well understood.
Additional information on specific weeds that may be found on-site will need to
be gathered as part of the mitigation plan. This information will include species’
preferred habitat, invasive strategies, means of propagation and eradication
methods.
Monitoring
A vegetation monitoring program will be implemented to ensure that a suitable
level of control is being achieved for low levels of exotic and unwanted species.
This program includes monitoring the effectiveness of exotic and unwanted
species control measures within the high-priority forest rehabilitation zones
