SLEMA Comments on the
Snap Lake Vegetation Monitoring Program 2006 Annual Report
Anne Gunn
February 2008
General Comments:
1. Overall the approach is relatively clear and well-presented.
2.The first objective is not quite correctly worded. The Area of Impact is to
confirm predictions related to loss or alterations of native vegetation
communities. But the reported results do not refer to the native vegetation
communities – instead it is the total footprint of the mine that was measured not
individual vegetation communities.
2. The second objective is essential a re-statement of this except instead of
native vegetation communities it is the Ecological Land Classification types. The
report needs to clarify what is meant by native vegetation communities relative
to the Ecological Land Classification types.
3. The report does not explain how the number of permanent plots or their
distribution (sample size) was derived – the lack of descriptive statistics makes it
difficult to assess, but the number of permanent vegetation sample plots seems
low. More detail and justification is needed to demonstrate that the sampling will
be adequate for the objectives.
Specific Comments:
1. Figure 1.2 Flowchart
Perhaps some arrows missing as in the triggered programs there is no line
connecting a change in vegetation from dust fall to “are the impacts extensive
and the cause uncertain” . Also the flowchart suggests that there would be dust
reduction measures even if vegetation not affected by dust.
2. Area of Impact
This refers to changes to the total Local Study Area through mine structures and
associated surface modification and dust On page 5, the text refers to changes
to native vegetation communities rather than the total Local Study Area.
Page 14 - The disturbance to the esker was three times the predicted level and
the type of change is not described. It does suggest that the trigger (15% of the
total Local Study Area is disturbed) is too broad and the unit should be not the
total Study Area but at the level of the native vegetation communities. The
report does not explain any details of adaptive management or mitigation for the
esker except to state (page 10) that it was reclaimed.
3. Ecological Land Classification Monitoring – this refers to indirect changes to
vegetation based on individual vegetation classes (topography and drainage) –
so why is dust as an indirect cause of change not included here and will only be
measured at the scale of the total Local Study Area (as it is included Area of
Impact)?
The report (page 13) states that 60% of the expected area is disturbed – without
explaining at what stage construction has reached relative to likely future surface
disturbance.
3. Reclamation
The rationale for the number and location of the permanent sample plots is not
either described or referenced. The plots at the esker are identified to monitor
natural recovery but the text also states that the gravel esker was reclaimed in
2001 – details should be included in the report. The methods do not explain how
the vegetation cover and species composition were determined (point frame or
what method).
4. The triggered Monitoring Programs
Detailed Ecological Land Classification Units
The selection of the treatment (exposed to mine activities) and control plots is a
weak design. It is too vague to state that the control plots were close enough to
be similar to the treatment plots but outside mine activities. What is the
assurance (references, sampling) that the control plots are outside the mine’s
zone of influence? All the control plots are with < 5 km and one (esker) is within
10 km – is that outside for example the influence of fine dust particles -was this,
for example, based on the known response of lichens at Ekati? It is also not
explained how the control and treatment plots compare for their ecological
characteristics.
5. Dustfall Monitoring
The text states that if the dust fall exceeds Alberta’s Ambient Air Quality
Objective for 3 months then De Beer’s triggered response may be to monitor the
Effect of dust on vegetation. However, it is unclear what the justification for
Alberta’s standards relative to arctic vegetation especially lichens? as they are
apparently ‘aesthetical’ . Another problem is that the 3-month period is not
explained especially as Alberta’s criteria is 30 days.
The text later in the report (p 30) does acknowledge that there is “no
scientifically defensible relationship between the criteria an defects on
vegetation” – however the report does not suggest a responses to this – should
those criteria be used or should there be a follow-up to either test the criteria or
develop more appropriate ones?
As the second criterion to trigger the effects of dust on vegetation monitoring is
the visual appearance of dust on vegetation, how does this criterion relate to the
first one (53-158 mg/dm2/30 days)?
There is no justification for using open dish dust collection – more typical given
the context is moss or lichen bags.
The report does not clearly state which effects of dust are being measured –
stating that it is changes in vegetation is too general – effects including physical
‘smothering’ which seems the intent here but there is also changes in pH and
uptake of chemicals. What about measuring the chemical content of lichens and
mosses?The number of sample plots is low and the sampling does not extend far
enough to measure the likely zone of influence of dust - the reference plot is
only about 2 km away from the mine.
The text (page 26) and Table 3.1 are not in agreement – the text states that the
maximum deposition rate of 102 mg/dm2/30 day was recorded at DF 008 in July
– the Table gives 12,700 mg/dm2/30 day for DF 010.
Why were the June samples not available?