Environmental Assessment
Volume B-4.1
Mine
Flora
Ambatovy Project
186
January 2006
Loss of habitat results in reduced population sizes and distribution ranges which
increase the risk of extinction (Burkey 1995). Thus, removing rare habitat at the
mine site during construction and operation phases may impact plant species
diversity and without mitigation could cause species extirpation or extinction.
However, based on recent aerial and reconnaissance ground surveys north of the
mine, other off-site azonal areas appear to exist in the region and may contain
similar rare species.
4.1.6.1 Assessment Methods
Flora surveys and associated research were carried out by MBG to develop a list
of
species of concern
to consider in the design and development of the mine
project. Priority 1 species are only known to occur within the mine footprint and
nowhere else in the world. Priority 2 species are only known to occur with the
mine LSA. These categories comprise the most important species to consider in
this assessment as their existence is directly threatened by the project.
The potential for species extirpation or extinction is a serious matter. Since this
possibility exists, it automatically rates the potential impact as a high
environmental consequence unless mitigations are effective at eliminating this
threat.
4.1.6.2 Assessment Criteria
The assessment criteria used for species loss are presented in Table 4.1-8.
Table 4.1-8 Impact Description Criteria for Species Loss
Direction
Magnitude
Geographic
Extent
Duration
(a)
Reversibility
Frequency
neutral: no change
in species
extinction
negative: a loss of
species
negligible: no
species extinction
high: one or more
species become
extinct
local: effect
restricted to the
LSA
regional: effect
extends beyond
the LSA
short term: <3
years
medium term:
3 to 30 years
long term: >30
years
reversible or
irreversible
low: occurs
once
medium: occurs
intermittently
high: occurs
continuously
(a)
Duration of exposure to risk of species loss.
