20060387 Ver 3_MACRO report 2009-4April Ph1+2+3_20090526

Benthic Macroinvertebrate Summary from
Rendezvous Mountain (NCDFR Purlear Creek) Stream Restoration Project
April, 2009
Benthic macroinvertebrates have been collected from 5 locations as part of a monitoring
project at Rendezvous Mountain. Phase 1 of this project was the restoration of a small
UT to Purlear Creek in July- August 2006, Phase 2 on the mainstem of Purlear Creek in
July- August 2007 and Phase 3 on the mainstem of Purlear Creek in April 2009.
Construction on Phase 3 was taking place during the benthic collection in 2009. Benthic
data were collected during spring surveys in 2005 through 2009. The 2005 and 2006
surveys were conducted prior to any construction activities. Site A is a small headwater
reach of Purlear Creek located above a large waterfall and was selected as reference
conditions for the restoration work on the UT (Site D). These two sites are
approximately the same size; Table 1 compares the data from these two locations only.
Biological samples were also collected from a reach of Purlear Creek below the waterfall
(Site B), within an inactive pasture (Site C or Phase 2 of this project), and from a
downstream recovery location (Phase 3). These data are summarized on Tables 1 and 2
of this report.
Table 1. Summary statistics from the stream restoration project at Rendezvous Mountain.
Site A is the reference for the restored reach (similar size features)
Metric /Survey
Total taxa richness
EPT taxa richness
EPT abundance
Dominant in Corm-non Taxa*
4 Indicator species
Site A, above falls
Site D, UT — restored
4/05
4/06
5/07
4/08
4/09
4/05
4/06
5/07
4/08
4/09
44
39
53
45
42
42
37
44
52
48
28
27
32
27
30
28
29
29
29
33
112
140
167
90
138
112
122
173
114
104
-
-
-
-
-
59%
59%
51%
50%
62%
24
21
24
22
20
23
24
13
26
23
*Abundant and Common taxa were used for this evaluation
The restoration activities at Site D appear to have minimally impacted the
ecological condition of the stream following the construction in 2006 (table 1). Taxa
richness and the abundance of EPT taxa are slightly higher following restoration (2007
and 2008) and DIC values were only slightly lower. This initial serge in taxa richness is
common following restoration and has been noted in numerous investigations. However,
many fewer indicator species were found at this site in 2007 and it appears caddisfly taxa
(most notably Rhyacophila, Neophylax and Nyctiophylax) were eliminated or reduced in
abundance. However many of these taxa re- appeared during the survey in 2008. Despite
slightly lower total taxa richness and EPT abundance in 2009 the dominant taxa in
common with the reference site increased to 62 %. These data suggests that the benthic
fauna are still evolving in this reach and that the conditions are similar to pre - construction
conditions. Shredder taxa often decline following restoration, as much less LPOM is
found in newly restored features. However the shredder community in this tributary is
healthy (Lepidostoma, Tallaperla, Tipula were all common or abundant during both post -
construction surveys).
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Table 2. Smmnary statistics from the stream restoration project at Rendezvous Mountain. Site B will be
used for reference for all mainsteln locations.
Total taxa richness
EPT taxa richness
EPT abundance
Dominant in
Common Taxa*
# Indicator snecies
Site B, below falls
Site C, pasture
Site #1, Purlear
4/05
4/06
5/07
4/08
4/09
4/05
4/06
5/07
4/08
4/09
4/05
4/06
5/07
4/08
4/09
55
45
57
43
44
64
58
59
49
51
66
52
57
42
48
36
31
34
27
29
41
34
34
31
37
37
35
34
24
27
159
122
189
90
111
170
143
165
113
118
199
140
173
103
124
-
-
-
-
-
63%
74%
62%
48%
65%
63%
56%
53%
38%
46%
33
27
25
24
22
33
26
27
23
1726
1 29
1 26
24
1 19
1 23
*Abundant and Common taxa were used for this evaluation.
Table 2 summarizes the benthic data from the main stem of Purlear Creek at
Rendezvous Mountain. Site B is above the confluence with the restored UT but below
the falls and was selected as the reference for this portion of the project. Site C (pasture
location) is below this tributary and was restored in the summer of 2007. The survey in
2008 was the first post - construction investigation at this location. Site 41 is the most
downstream location of this project; construction during Phase 3 of the Rendezvous
Restoration occurred during the benthos collection in 2009 — 2010 will be the first post -
construction survey at this location.
Taxa richness and EPT abundance values were significantly lower at both
reference locations (Sites A and B) in 2008. This may be a response to watershed wide
conditions or the negative impacts of very low flow. Conditions improve at both
locations in 2009. Following construction within the pasture in 2007 moderately lower
taxa richness and EPT abundance values were seen. It is difficult to conclude that these
lower numbers were due to the construction activities or the negative effects of very low
flow. However conditions appear to have rebounded quickly at this location. All
summary metrics were higher during the 2009 investigation. These data indicate that the
construction activities in this reach of Purlear Creek had very little negative impacts to
the benthic fauna. Recovery of the fauna at this reach is likely due to the nearby sources
of recolonization and refuge.
Compiled and prepared by Dave Penrose for NCSU Bio & Ag Engineering.
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