Wambo Coal AEMR 2011-2012 - Peabody Energy

2.3 Discussion
2.3.1 Species Diversity within Quadrats
Variation in the number of species recorded in 2011 between quadrats is a factor of:
• Within vegetation communities:
» Differences in quadrat conditions, such as minor differences in aspect, slope, and
soil type;
» Inherent differences in the species composition of a single vegetation community
throughout the community; and
» Variation in the amount of rainfall at each quadrat.
• Between vegetation communities:
» The different species composition of different vegetation communities, generally
as a result of different site characteristics, such as slope, aspect, soil type, etc.
Variation in the number of species recorded across the five years of sampling is likely a
factor of:
• Seasonal conditions:
» The increase in the number of species at all quadrats in 2007 is likely a result of a
good season;
» The general decrease in the number of species at quadrats in 2008 is likely a
result of a poor season; and
» Moderate to minor fluctuations in the number of species recorded in quadrats in
2009, 2010 and 2011 are likely a result of moderate seasonal conditions.
• The timing of surveys:
» Cryptic species such as orchids have only a short flowering and detectable
period. Surveys completed in different months or even weeks of the year are
likely to detect a different range of cryptic species;
» There is no evidence to suggest that the number of flora species at any quadrat
are being affected by current mining practices; and
» Current land management practices within the RWEP areas appear to be
appropriate for the conservation of flora species diversity.
2.3.2 Introduced Species Percentage Composition
Variation in the introduced species percentage composition is likely due to:
• Vegetation community/quadrat landform location. The three vegetation communities
that recorded more than 25 percent of introduced species are all located within
riparian locations where propagules (seeds and vegetative material) from weed
species are easily distributed by moving water;
• Variation in seasonal conditions from year to year;
2011 Annual Ecological Monitoring Report, Final Report, May 2012 Page 12