Dec 20, 2000 - ILLINOIS DEPARTMENT OF NATURAL RESOURCES. 524 SOUTH SECOND STREET. LINCOLN TOWER PLAZA. SPRINGFIELD, IL 62701- ...
I L L I N 0 I S UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
PRODUCTION NOTE University of Illinois at Urbana-Champaign Library Large-scale Digitization Project, 2007.
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Natural History Survey Library
SUBTERRANEAN AMPHIPODA (CRUSTACEA) OF ILLINOIS' SALEM PLATEAU: SPATIAL AND TEMPORAL COMPONENTS OF MICRODISTRIBUTION
Steven J. Taylor and Donald W. Webb Illinois Natural History Survey 607 East Peabody Drive Champaign, IL 61820 (217) 333-6846
20 December 2000 Illinois Natural History Survey Center for Biodiversity Technical Report 2000(27)
PREPARED FOR ATTN: C2000 COORDINATOR OFFICE OF REALTY AND ENVIRONMENTAL PLANNING ILLINOIS DEPARTMENT OF NATURAL RESOURCES 524 SOUTH SECOND STREET LINCOLN TOWER PLAZA SPRINGFIELD, IL 62701-1787
Executive Summary This report presents results of a quantitative field study of amphipods and other invertebrates found in four cave streams in Illinois' Salem Plateau. We conducted field experiments in Illinois Caverns which indicated that Gammarus troglophilus Hubricht and Mackin (Amphipoda: Gammaridae) and Gammarus acherondytes Hubricht and Mackin, the federally endangered Illinois Cave Amphipod, both preferred larger (12.7 to F that was >0.05, we considered the subsequent variables in the model to be of little additional value in explaining variance. The same regression techniques were used to examine the value of gravel metrics and time (expressed as increasing monthly integers from 1 (April 1999) to 12 (March 2000) in predicting amphipod size (as measured by head length) for each species in each cave. These analyses were only conducted when sample size for a species in a cave was >20. Although the regression analyses (above) are fairly robust relative to violations of assumptions, our data do not meet all assumptions and results should be interpreted with some caution. We examined species diversity using the Shannon-Wiener diversity index, H' (Shannon 1948). The value of this popular index has been questioned, and Boyle et al. (1990) recommend that diversity indices be used only in concert with other metrics. Because H' is affected by both the distribution of the data and by the number of categories, many users prefer to use a related measure, evenness (J') (Pielou 1966), which corrects for the number of categories (Zar 1984). Therefore, we computed both H' and J' for our samples. We also examined variations in species richness and a potential tool for assessing community health, the Gammarus : troglophilic Caecidotearatio (Whitehurst 1991la, b). Data analyses, including correlation, regression and general linear models procedures, were conducted using SAS (SAS Institute 1988) and Splus (MathSoft 1999). Results of statistical tests are considered significant at P 2x2 cm, or >0.0004 m2), but may be roughly comparable to their riffle samples. Culver and Fong (1991) found that co-occurence of taxa was generally higher than expected in riffle samples, but it was generally low for individual stones. Our results, therefore, appear to be in agreement with Culver and Fong (1991) in that co-occurence in samples generally was found more often than expected (as for their riffle samples). Their work, and earlier studies by Culver (1970, 1971) suggests that we should not expect amphipod taxa to co-occur under individual stones because of antagonistic interactions (competition and/or predator prey relationships). Weakly positive associations of species observed in our samples might reflect commensal realtionships, proximity of predator and prey, or concentrations of competing animals associated with limited resources (e.g., food [organic debris or other taxa] or shelter [suitable substrate]) (Culver and Fong 1991). It would be most interesting to follow up this work by examining crustacean species assemblages under individual stones in the caves streams in our study area.
17
Several studies have shown that using a Gammarus'Asellus ratio as an index for assessing organic enrichment is useful in epigean lowland rivers (e.g., Whitehurst 1991a, b; Whitehurst and Lindsey 1990). Our data (Tables 1, 11, 13; Figure 30) suggest that there are differences between caves in the proportions of gammarids and isopods. A Gammarus:troglophilicCaecidotea ratio was calculated and was found to differ among caves (Table 11). In spite of this significant difference, the ratio was fairly variable within each cave (Figure 30). Also, it was not always possible to calculate this ratio (that is, when the denominator, troglophilic Caecidotea,was zero), which is reflected in the reduced sample sizes for this ratio relative to other parameters in Table 11. Because of these two problems (1: high within-site variability in the ratio; and 2: it was not always possible to calculatethe ratio), this ratio does not seem like a particularly useful management tool for assessing organic pollution in cave streams of the Salem Plateau.
Conclusions This study highlights the importance of substrate, seasonality, and interactions with other taxa in explaining the distribution and abundance of amphipods in the karst groundwater of Illinois' Salem Plateau. Our results point towards organic enrichment, pH, and oxygen levels as being among the potentially important influences on community structure. Although much remains to be learned about crustacean communities in these cave streams, management actions which serve to improve or maintain karst groundwater quality are thus likely to be in the best interests of the cave stream communities.
Acknowledgements We thank the following individuals for assistance with field work: Ginny Adams (Southern Illinois University at Carbondale), Julie Angel (Illinois State Water Survey), Lisa Brennan (Southern Illinois University at Carbondale), R. Edward DeWalt (Illinois Natural History Survey), Barb Capocy (Indiana Karst Conservancy), Rick Haley, Chris Hespin (Illinois Department of Natural Resources), Joe Kath (Illinois Department of Natural Resources, Endangered Species Project Manager), Suzanna Langowski (formerly US Army Construction Engineering Research Laboratories), Cindy Lee (Southern Illinois University at Carbondale), Dave Mahon (Mark Twain Grotto), Brenda MolanoFlores (Illinois Natural History Survey), Philip Moss (Ozark Underground Laboratory), Sammuel V. Panno (Illinois State Geological Survey), Gary Resch (Little Egypt Grotto), Jeanne Roberts (Southern Illinois University at Carbondale), Genie and Geoff Schropp (Little Egypt Grotto), Heidi Stuck (University of Illinois), Jack Taylor, Diane Tecic (Illinois Department of Natural Resources, Heritage Biologist), Marc Tiritilli (Near Normal Grotto), Rick Toomey (Illinois State Museum), Kelly Victory (Illinois Department of Natural Resources), Jeff Walaszek (US Army Construction Engineering Research Laboratories), C. Pius Weibel (Illinois State Geological Survey), Mark J. Wetzel (Illinois Natural History Survey), Father Paul Wightman and Richard Young (Little Egypt/SEMO Grotto). University of Illinois (Urbana-Champaign) students Wendy Borchert, Bogdan Ciuca, Anne Dennett, Alexandra Santau-Sodhi, Heidi Stuck and Mike Wallace assisted with laboratory work. We thank Matt Nelson (The Nature Conservancy), Philip Moss, and Drs. John Holsinger (Department of Biological Sciences, Old Dominion University), Jerry Lewis, Daniel Fong (Department of Biology, American University) and Horton Hobbs III (Department of Biology, 18
Wittenberg University) for helpful discussions. We thank the Illinois Speleological Survey, The Nature Conservancy, the National Speleological Society, Little Egypt Grotto, Mark Twain Grotto, and Near Normal Grotto for their cooperation and assistance. Diane Tecic and Debbie Newman (Natural Areas Preservation Specialist) were particularly helpful in arranging permission to access the caves. We thank Homer and Loretta Stemler and Cletus and Sharon Kelley for their generosity in allowing us to visit their caves. Joan Bade (Illinois Department of Natural Resources), Chris Hespin, Joe Kath, Gerry Bade (U.S. Fish and Wildlife Service), Harry Hendrickson (Illinois Department of Natural Resources, Division of Energy and Environmental Assessment) and Randy Heidorn (Illinois Department of Natural Resources) helped with various issues associated with this study. Jocelyn Aycrigg, Tom Kompare, and Diane Szafoni (all Illinois Natural History Survey) assisted with various computer-related issues. The Illinois Department of Transportation and the Illinois Natural History Survey provided some logistical support. Barb Capocy provided helpful editorial comments on an earlier draft of this manuscript. We thank Chris Philips, Larry Page, and Geoff Levin (all Illinois Natural History Survey) for allowing SJT to commit time to this study.
19
Table 1. Comparison of potentially important parameters among caves where Gammarus acherondytes appears to differ in 'success' as measured by average density of individuals per m 2 (histogram bars). Mean values of N=12 (N=1 1 for some metrics in Stemler Cave) or more monthly sampling periods, except cave length and basin area. Fogelpole Cave
Parameter Gammarus
8
L % ,, d..
6
cnerunuytes
density (individuals oer m 2)
Illinois Caverns
Krueger-Dry Run Cave
Stemler Cave
i
I
4 2 0
_________________R_________I
G. troglopilus density (individuals per m2 )
39.17
4.10
3.68
21.82
C. forbesi density (individuals per m2)
0.38
0.26
3.53
2.72
Isopoda1 dominance (% in samples)
52.77
33.28
82.89
29.51
Gravel Metrics 2: D16
52.92
10.82
6.98
10.95
Median grain diameter (D5 0 )
130.81
26.20
20.30
45.43
D84
198.75
54.16
40.65
99.22
98.76
23.26
16.51
31.16
107.71
23.95
17.65
34.93
2.41 -0.162
2.62 -0.247
3.57 -0.247
Geometric mean diameter(dg) Graphic mean diameter (mg) Geometric sorting index (sg) Skewness (sk) Fecal coliform bacteria 3 (cfu/100 ml H20O)
2.23 -0.340
>1074.92
382.17
20
>1161.75
770.17
Table 1. Continued. Foglepole Cave
Parameter Gammarus S1-_
achneronaytes density (individuals2 pner I
m )/
8
6
Illinois Caverns
Krueger-Dry Run Cave
Stemler Cave
i .-----
I
4 2 0 -
Water Chemistry 3:
pH
8.12
8.08
8.11
7.61
Specific Conductivity (plS/cm)
578.13
543.53
652.35
678.77
Dissoloved Oxygen (mg/L)
9.48
9.07
9.07
7.81
Turbidity (FTU)
69.47
38.44
44.68
39.22
Nitrate Nitrogen (ppm)
2.42
4.03
2.84
2.81
(°C)
12.87
13.15
13.64
13.55
Alkalinity (as CaCO3)
219.92
199.82
242.82
243.82
Total Dissolved Solids (ppm)
284.08
273.17
355.75
378.08
Phosphate (PO4)(ppm)
0.41
0.53
0.61
0.91
(SO4- 2)(ppm)
40.92
27.83
57.33
60.92
Chloride (Cl-) (ppm)
24.17
27.08
29.58
33.17
Water Temperature
Sulfate
21
Table 1. Continued. Foglepole Cave
Parameter Gammarus 77 acneronaytes density (individuals ner nm2
Illinois Caverns
Krueger-Dry Run Cave
Stemler Cave
8
I
6
4 2
0
Drainage Basin Size4 (km 2) Cave Length5 (km)
18.51
5.44
13.99
24+
8.8
-11
1Primarily
18.51 1.8
Caecidoteabrevicauda Gravel metrics (D 16 , Dso, D84, dg, mg, sg, sk) are not representative of entire cave, only of sampling site, and the same may be true of the invertebrate samples, as they were collected only in one area in each cave 3Taylor et al. (2000) 4Aley et al. (2000), includes entire basin from resurgence springs 5Webb et al. (1998) 2
22
Table 2. Descriptive statistics used in the analysis of substrate size class data from Hess and Surber samples (Folk 1980, Inman 1952, Kondolf 1997, Kondolf and Li 1992, Vanoni 1975). Statistic
Description
D50
Median grain diameter (mm)
84,DI6
Grain diameter (mm) at which 84% (D84) and 16% (D16 ) of the grain diameters are smaller.
dg
Geometric mean diameter (mm) = (D16 * D84) 0 '5
mg
Graphic mean diameter (mm) = 0.33 3 (D16 * Do * D84)
sg
sk
5 Geometric sorting index = (D8 4 / D16)°' This index reflects how well sorted the grains are. A high sg value indicates poorly sorted material.
Skewness = log(dg / D5o) / log(sg) This index reflects how symetrical the distribution of grain sizes is around the median.
Table 3. Mean head lengths (mm) and precentages of individuals selecting each gravel size class in choice experiment. Gravel Size Class (mm) Species
2.36 to 50.8
r
r2
0.9144 0.9638 0.9987 0.9818 0.9781 0.9852
0.8361 0.9289 0.9974 0.9639 0.9566 0.9707
Count r
r2
0.9145 0.9637 0.9228 0.5829 0.9817 0.6586
0.8363 0.9288 0.8515 0.3398 0.9638 0.4337
P 0.0039 0.0005 X 2 Differences
Stemler Cave
Test Value
0.246 77 A B
42.151
0.0000
Yes
Evenness (J')
0.222 84 A
0.088 84 B
0.123 84 A
0.189 77 A
42.163
0.0000
Yes
Species Richness (n)
2.714 84 A
1.250 84 B
2.250 84 A
2.169 77 A
49.026
0.0000
Yes
0.179 64 A
0.642 75
0.503 59 A
0.558 34 A B
20.4131
0.0001
Yes
Gammarus : troglophilic CaecidoteaRatio
B
29
Table 12. Comparison of levels of community parameters in relation to the presence or absence of Gammarus acherondytes and Gammarus troglophilus.
Mean Value N Species
Parameter
Cave
Species Absent
Species Present
df
Test Statistic'
P
Significant Difference
Gammarus troglophilus Fogelpole Cave Species Diversity
(H')
0.121 27
0.368 57
82
-8.4211
0.0000
Yes
0.093 27
0.283 57
82
-8.4268
0.0000
Yes
1.519 27
3.281 57
82
-6.7547
0.0000
Yes
0.004 43
0.537 21
62
-5.4865
0.0000
Yes
0.079 67
0.254 17
82
-3.7447
0.0003
Yes
0.060 67
0.195 17
82
-3.7482
0.0003
Yes
0.970 67
2.353 17
82
-4.5694
0.0000
Yes
0.096 23
0.883 52
73
-2.6700
0.0093
Yes
Evenness
(J') Species Richness
(n)
Gammarus: troglophilic Caecidotea Ratio Illinois Caverns Species Diversity
(H') Evenness (J') Species Richness
(n) Gammarus : troglophilic CaecidoteaRatio 2
30
Table 12. Continued. Mean Value N Species
Parameter
Cave
Species Absent
Species Present
df
Test Statistic'
P
Significant Difference
Gammarus troglophilus Krueger-Dry Run Cave Species Diversity
(H')
0.122 64
0.283 20
82
-3.8659
0.0002
Yes
0.094 64
0.218 20
82
-3.8663
0.0002
Yes
1.797 64
3.700 20
82
-5.2442
0.0000
Yes
0.032 36
1.234 23
57
-4.9980
0.0000
Yes
0.129 33
0.334 44
75
-4.4521
0.0000
Yes
0.099 33
0.257 44
75
-4.4557
0.0000
Yes
1.424 33
2.727 44
75
-4.2208
0.0001
Yes
0.005 20
1.348 14
-5.3337
0.0000
Yes
Evenness
(J') Species Richness
(n) Gammarus : troglophilic CaecidoteaRatio Stemler Cave Species Diversity
(H') Evenness
(J') Species Richness
(n) Gammarus : troglophilic CaecidoteaRatio
31
Table 12. Continued. Mean Value N Species
Parameter
Cave
Species Absent
Species Present df
Test Statistic'
P
Significant Difference
0.245 64
0.429 20
82
-4.7330
0.0000
Yes
0.188 64
0.330 20
82
-4.7354
0.0000
Yes
2.313 64
4.000 20
82
-5.5444
0.0000
Yes
0.181 62
0.106 2
-1.3669
0.1717
No
0.088 68
0.224 16
82
-2.7539 0.0073
Yes
0.068 68
0.172 16
82
-2.7548 0.0072
Yes
1.029 68
2.188 16
82
-3.5924
0.0006
Yes
0.539 64
1.238 11
73
-1.7735
0.0803
No
Gammarus acherondytes Fogelpole Cave Species Diversity
(H') Evenness
(J') Species Richness
(n) Gammarus: troglophilic CaecidoteaRatio Illinois Caverns Species Diversity (H') Evenness
(J') Species Richness
(n) Gammarus : troglophilic Caecidotea Ratio 2
32
Table 12. Continued. Mean Value N
Species
Cave
Parameter
Species Absent
Species Present
df
Test Statistic 1
P
Significant Difference
57
-5.2567
0.0000
Yes
Gammarus acherondytes Krueger-Dry Run Cave 2 Species Diversity (H')
0.143 77
0.350 7
0.110 77
0.269 7
2.104 77
3.857 7
0.147 44
1.547 15
Evenness
(J') Species Richness
(n) Gammarus : troglophilic CaecidoteaRatio Stemler Cave 2' 3 1Two-Sample
t-Test with t statistic given, except that for Gammarus troglophilusin Stemler Cave and Gammarus acherondytes in Fogelpole Cave, the Gammarus:troglophilicCaecidoteaRatio a Wilcoxon rank-sum test was used with Z statistic given 2Not tested, inadequate sample size 3 No Gammarus acherondytes present
33
Table 13. Average number of animals per m2 (N=7 samples/month/cave) for all taxa in cave stream substrate. Cave Taxon
Sep
Oct Nov
Dec
Jan
Feb
Mar Avg
Jun
Jul Aug
166.11 284.05 192.69
58.37 32.26
46.08 121.35
50.69 36.87
64.52 62.98 30.72 95.56
43.01
30.72 52.23
21.51
6.14
12.29
29.19
1.54 39.17
Apr May
Fogelpole Cave Isopoda' G. troglophilus Oligochaeta
2
23.26
41.53 201.00
131.23 107.97
34.88
7.68
18.43 62.98
6.14
3.07
12.29
19.97
4.61
1.54
15.36 34.87
24.58
3.07
1.54
1.54
0.00
0.00
0.00
1.54
0.00 6.56
G. acherondytes
0.00
3.32 43.19
C.forbesi
0.00
0.00
0.00
1.54
3.07
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.38
B. brachycaudus
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
Amphipoda 3
3.32
0.00
0.00
9.22
0.00
0.00
1.54
0.00
1.54
0.00
1.54
0.00
Chironomidae
1.66
4.98
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.55
Nematoda
1.66
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.14
Coleoptera
0.00
1.66
3.32
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.42
Turbellaria
0.00
1.66
1.66
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.28
Ephemeroptera
0.00
1.66
0.00
0.00
1.54
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.27
Hirudinea
0.00
3.32
3.32
1.54
0.00
0.00
3.07
0.00
0.00
0.00
0.00
0.00 0.94
Decapoda
0.00
0.00
0.00
1.54
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.13
Gastropoda
0.00
0.00
0.00
0.00
1.54
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.13
Bivalvia
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
Tipulidae
0.00
0.00
0.00
0.00
0.00
1.54
0.00
0.00
0.00
0.00
0.00
0.00 0.13
Ceratopogonidae
0.00
0.00
1.66
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.14
Trichoptera
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Other Diptera
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
34
1.43
0.00
Table 13. Continued. Cave Taxon
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar Avg
0.00 71.43
6.64
18.43
7.68
0.00
4.61
4.61
0.00
9.22
3.07
6.14 10.99
3.32
16.61
1.66
9.22
0.00
4.61
0.00
1.54
1.54
3.07
6.14
1.54 4.10
11.63
54.82
9.97
4.61
6.14
0.00
3.07
0.00
1.54
6.14
6.14
3.07 8.93
G. acherondytes
0.00
1.66
0.00 21.51
4.61
4.61
6.14
7.68
3.07
3.07
0.00
0.00 4.36
C.forbesi
0.00
0.00
0.00
0.00
1.54
0.00
0.00
0.00
0.00
1.54
0.00
0.00 0.26
B. brachycaudus
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
Amphipoda 3
0.00
29.90
4.98
1.54
0.00
0.00
0.00
0.00
0.00
0.00
0.00
1.54 3.16
Chironomidae
0.00
3.32
1.66
1.54
0.00
0.00
0.00
0.00
0.00
1.54
0.00
0.00 0.67
Nematoda
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
Coleoptera
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
Turbellaria
0.00
0.00
0.00
1.54
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Ephemeroptera
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
Hirudinea
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
Decapoda
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
Gastropoda
4.98
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.42
Bivalvia
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
Tipulidae
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
Ceratopogonidae
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
Trichoptera
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
Other Diptera
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
Apr May
Illinois Caverns Isopoda' G. troglophilus Oligochaeta
2
35
0.13
Table 13. Continued. Cave Taxon
Apr May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar Avg
75.27 132.10 130.57 242.70 116.74
58.37171.16
Krueger-Dry Run Cave Isopoda'
1.66 290.70 137.87 413.21 347.16 107.53
13.29
0.00
1.54
4.61
1.54
0.00
0.00
1.54
7.68
6.14
6.14 3.68
1.66 59.80
3.32
32.26
4.61
0.00
3.07
1.54
1.54
6.14
6.14
0.00 10.01
G. acherondytes
3.32
1.66
0.00
0.00
0.00
0.00
0.00
0.00
4.61
1.54
0.00
1.54
C.forbesi
0.00
11.63
0.00
3.07
1.54
1.54
1.54
3.07
16.90
1.54
1.54
0.00 3.53
0.00
4.98
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.42
0.00
0.00
0.00
0.00
0.00
0.00
0.00
1.54
0.00
0.00
0.00
0.00 0.13
Chironomidae
0.00 39.87
0.00
0.00
3.07
3.07
1.54
0.00
0.00
0.00
1.54
0.00 4.09
Nematoda
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
Coleoptera
0.00
8.31
0.00
13.82
3.07
3.07
3.07
1.54
1.54
3.07
0.00
0.00 3.12
Turbellaria
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
Ephemeroptera
0.00
88.04
4.98
1.54
0.00
0.00
0.00
3.07
0.00
0.00
0.00
0.00 8.14
Hirudinea
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
Decapoda
0.00
0.00
1.66
0.00
0.00
1.54
1.54
0.00
0.00
0.00
0.00
0.00 0.39
Gastropoda
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
Bivalvia
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
Tipulidae
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
Ceratopogonidae
0.00
1.66
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.14
Trichoptera
0.00
0.00
0.00
0.00
0.00
3.07
0.00
1.54
0.00
0.00
0.00
0.00 0.38
Other Diptera
0.00
0.00
0.00
0.00
0.00
3.07
0.00
0.00
0.00
0.00
0.00
0.00 0.26
G. troglophilus Oligochaeta
2
B. brachycaudus Amphipoda
3
1.66
36
1.06
Table 13. Continued. Cave Taxon
Apr May
Jun
Jul
Aug
Sep
Oct Nov
Dec
Jan
Feb
Mar Avg
. 127.91
49.83 47.62 35.33
15.36
1.54
6.14
12.29
27.65
19.97
13.82 29.79
. 93.02
18.27
15.36
9.22
6.14 13.82
10.75 21.51
12.29 21.82 16.90 34.96
Stemler Cave 4 Isopoda' G. troglophilus Oligochaeta
2
. 162.79 124.58
27.65 33.79 12.29
19.97
0.00
0.00
3.07
3.07
9.22 67.59
G. acherondytes
.
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00 0.00
C.forbesi
.
4.98
0.00
6.14
4.61
0.00
1.54
1.54
1.54
1.54
4.61
6.14
2.72
.
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
. 54.82 41.53
0.00
0.00
0.00
0.00
1.54
0.00
0.00
9.22
0.00 8.92
Chironomidae
.
6.64
1.66
0.00
0.00
0.00
0.00
0.00
0.00
0.00
1.54
0.00
0.82
Nematoda
.
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Coleoptera
.
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Turbellaria
.
1.66
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.14
Ephemeroptera
.
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Hirudinea
.
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Decapoda
.
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Gastropoda
.
0.00
6.64
0.00
3.07
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.81
Bivalvia
.
8.31
3.32
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.97
Tipulidae
.
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Ceratopogonidae
.
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Trichoptera
.
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Other Diptera
.
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
B. brachycaudus Amphipoda
3
2 'Isopoda are almost exclusively Caecidotea brevicauda; Values for Oligochaeta represent counts of whole individuals 4 plus fragments, so this group may be less dominant than is suggested here; 3 Undtermined individuals; No sampling was done in April, 1999, in Stemler Cave
37
Table 14. Co-occurence of amphipod and isopod taxa in quantitative cave stream samples in four caves across one year sampling period. When expected co-occurence frequency could be calculated, it is given in parentheses, and when the observed value was less than expected, these numbers are in bold italics. Frequency of Occurrence by Cave 2 Species Pair1 Gammarus troglophilus
0 0 1 1
FOG P 3
Gammarus acherondytes 25 0 2 1 39 0 1 (1.2)18
ILC
56
0 0 1 1
Crangonyx forbesi 0 1 0
27 0 54 3
0.2980
0 0 1 1
Isopoda 4 0 3 24 1 3 0 (12.0)54 1 0.3808
Gammarus acherondytes
0 0 1 1
Crangony.x forbesi 62 0 1 2 19 0 1 (0.5)1
0 0 1 1
Isopoda 4 4 0 1 60 2 0 1 (20)18
Crangonyx forbesi
0 0 1 1
Isopoda 4 0 1 0 1
6 58 2 (14.5)18 1.0000 1.0000 64 13 5 (0.9)2
44 24 11 (4.8)5
6 0 3 1.0000
0.0930
28 49 0 0
(8.8)6 1.0000
0.5173
25 36 3 (3.9)13
8 61 0 15 0.1165
16 17 12 (7.3)32
61 16 0 0
7 70
54 27 0 2
75
0.3974
0.6030
0.0344
0.6249
28 5 33 (2.7)11 0.1769
68 0 14 2 0.5627
Gammarus acherondytes
33 0 44 0
55 9 14 (1.8)6 0.3657
44 23 11 (4.6)6
STM P 3
0.0520
66 1 16 ((0.2)1 0.5478
Gammarus troglophilus
KDR P 3
61 3 16 (5.1)4
11 12 (1.9)5 0.0151
Gammarus troglophilus
P3
0.3401
0.1454
'l=present, 0=absent; 2FOG=Fogelpole Cave (n=84), ILC=Illinois Caverns (n=84), KDR=Krueger-
Dry Run Cave (n=84), STM=Stemler Cave (n=77); 3Fisher's Exact Test, two tailed (not tested for species pairs in Stemler Cave that include Gammarus acherondytes); significant results are in bold and underlined, near-significant results are underlined; 4 Primarily Caecidotea brevicauda
S 3Kilometers Kilometers
Figure 1. Location of study sites (from Taylor et al. [2000]). Cave drainage basins are from Aley et al. (2000), sinkhole areas (shaded) are from Panno et al. (1999).
39
100 9080s 70 60 50 4C 3C 2(
)ole Cave Cave j Run Cave
r
-3
Figure 2. Percent of maximum cave stream stage during monthly (1999 - 2000) sampling at four caves. From Taylor et al. (2000). A
__
30
20 10
0
B
30
It
20
I-
A r%..
10
II 0.46
0.86
777 1.26
1.66 2.06 Head Length (mm)
2.46
2.86
3.26
Figure 3. Frequency distribution of head sizes of amphipods used in gravel choice experiment at Illinois Caverns. A, Gammarus troglophilus; B, Gammarus acherondytes.
40
Fogelpole Cave
-1
I
0 A.YW-Tý 200400 .Y W
0 200400
.w
Illinois Caverns
I n
5 10w
/
D16 400= 200
D50
u:
-100 -u
p
^_
U-
c)
200 0
0
0 20040
0
) 2004 0
8
__-
D50
10
0
D16
0
.....
*C
0 10 20
-0.0100SDG 80
MG-40
4
0
0 100200
0
I
40 80
100 -50 =0 SG
U
10 5 0 SK-0.0
4
r
0 501( 10
31002C10
0
1
-1 -0
DS0
D84 DG
5 10
•.'
°
L..
00
-100 =0 'nnU
MG
0 100200
10 0
IF i%,2-i%-ý F Lrt
317 >o
--1 1
0
-1
0 50100
-0.5 0.0 0.5
0 1002( 0
1
S
200 ="
o
je
3 1002( 0
00
0
DG
S1002 J 1002w
) 20
0
50-
c I
SK
0 200
01
0uu -100 00
MG
-1 0 4
0
0 50100
40 80
Dof6
80 40
SK
1 -0 -1
7w-i
D84
1 10 50-
SG
)* 0 1002110
-n *u
100 50U-
-400 200 -0
MG
-4U -20
D50
-Ann
CA 3
0-
i,I
10
5
0
100
50
2UU
DG
o
105-
0
00200
D16
I II= dtUU
F LAV
1
0
-
100-
D84
400] 200
i
C-200
L
00
SG SKIi :.0 *^ *. 111 1 a
0 100200
-1
0
Stemler Cave
Krueger-Dry Run Cave
Figure 4. Correlations among the various gravel metrics (Table 2) by cave across all sample replicates and months (April 1999-March 2000). N=84 samples for all caves, except that for Stemler Cave N=77.
41
B
A
0
0
40
-44
E 020
0
0 0
5
2500
>32
D
C 0
•,
)
0
E220
-
.
0
Boom --.
tl'
4ou
E
0
0
>160
1700
1300 count
900
7500
t
500
700
900
500
700 count
900
0
0
>350 I
I
115
I
130 count
145
2.0 count
3.5
E
L
0600 E 6300
500 (D E 6200
I
0
0
0
11
0
22 count
0.5
33
Figure 5. Correlation between gravel volume and gravel counts. Gravel size classes (mm): A, 2.36 to 4.75 to 12.7 to 25.4 to 50.8. B
A 40
0
0
50
-
0
E =3
0
E30
"520
>30 44 grams
22
160
84 grams
106
-
0
-3 -
310
420
530
310
420 grams
530
>350
-
720
840
960
720
840 grams
960
F
E
600
oo E
106
E
E220 -
5300
84
D 450
0600 o
0
62 62
66
C_________
>160
0
-
C)
L
E -200
0 -
II
0 0
500
1000 grams
--
.I
200
1500
-
.i
500 grams
800
Figure 6. Correlation between gravel volume and gravel weight. Gravel size classes (mm): A, 2.36 to 4.75 to 12.7 to 25.4 to
