A Natural History of Millbrook Marsh,
A Wetland In An Urbanizing Setting

Invertebrates

Invertebrates are a key part to the wetland ecosystem as an invaluable part of the food web as well as their newer but more commonly known use as indicators of the health of aquatic systems. Much is known about the invertebrate species that are water quality indicators, but not nearly as much is known of others. It is probable, though, that small invertebrate consumers are even more important with regard to detritus decomposition in wetlands than are the large invertebrates, unlike the situation in terrestrial ecosystems (Bursey 1989). At the bottom of the food chain in the wetland, plant litter is colonized by microorganisms and this detritus is used by the first invertebrates, shredders or grazers, for example, amphipods and snails. The litter particles are reduced in size by their feeding activity and the smaller particles are then used by either collectors or filter feeders (chironomids for example), depending on their size. Invertebrates also feed on algae, usually abundant in wetland ecosystems, though algae is sometimes not as plentiful in vegetated systems (Cole, pers. comm.). They are one of the critical links in the food chain, prey for fish, waterfowl and other birds, amphibians, reptiles and mammals. They are a part of the nutrient cycling processes both directly and indirectly (Murkin and Wrubleski 1988).

Stream Macroinvertebrates

The macroinvertebrate communities in the stream reaches of Thompson Run and Slab Cabin Run were surveyed in July and October of 1997 (Brooks et al. 1998). Stations 1, 5, and 6 were located in Thompson Run and Stations 2, 3, and 4, in Slab Cabin Run. They revealed moderately depauperate macroinvertebrate fauna in both streams (Table 6-1). In Slab Cabin Run, 24 species were found in July and 31 species in October. The most common taxa were chironomids and hydropsychid caddisflies, and the average species richness was 17.2. In Thompson Run, 19 species were found in July and 15 in October. Midge larvae and blackfly larvae were most common and the average species richness was 11.0. The least disturbance in the macroinvertebrate community shown by RBP III was at the "Slightly Impaired" Station 2, compared to all other stations which were classified as "Moderately Impaired". The number of pollution intolerant taxa present in both streams, the mayflies, stoneflies, and caddisflies, was low at all stations, and the Hilsenhoff Biotic Index suggested that Station 2 of Slab Cabin Run is the only one not affected by organic pollution as are the other stations in Slab Cabin and Thompson Runs. Additionally, there were low values for scrapers/filterers at all but Station 4, indicating a high value for filtering collectors. This suggests a disproportionate amount of fine particulate organic matter. There was also an overabundance of pollution tolerant chironomids, shown by the EPT/Chironomidae Index. A large portion of the total macroinvertebrate community was made up by the most dominant taxon, which, in a healthy community, should contribute less than 20% (Brooks et al. 1998). All of this suggests a generally unbalanced community.

Table 6-1
1997 Millbrook Marsh Benthic Macroinvertebrates (Brooks et al. 1998)

 

July 1997

 

October 1997

 

Thompson Run

Slab Cabin Run

 

Thompson Run

Slab Cabin Run

 

1

5

6

2

3

4

 

1

5

6

2

3

4

Insecta                          
Ephemeroptera                          
Baetidae                          
Baetis sp.

23

8

20

16

2

3

 

51

21

22

7

8

3

Heptageniidae                          
Stenonema sp.                    

15

   
Tricorythodae                          
Tricorythodes sp.          

3

             
Trichoptera                          
Glossosomatidae                          
Glossosoma sp.                        

1

Hydropsychidae      

1

4

               
Ceratopsyche sp.  

4

9

123

57

11

     

1

57

77

3

Cheumatopsyche sp.      

4

 

20

       

2

2

3

Hydropsyche sp.  

1

2

18

 

2

       

29

6

3

Hydroptilidae                          
Hydroptila sp.                        

1

Ochrotrichia sp.

2

3

3

4

8

2

             
Limnephilidae                          
Pycnopsyche                      

1

 
Psychomyiidae                          
Psychomyiia sp.      

5

                 
Rhyacophilidae                          
Rhyacophila sp.                    

2

   
Diptera                          
Ceratopogonidae                          
Forcipomyia sp.          

4

             
Chironomidae

96

131

161

45

88

156

 

158

196

139

32

85

56

Empididae                          
Chelifera sp.  

1

                     
Muscidae

15

2

7

       

9

11

4

1

2

 
Nymphomyiidae                          
Nymphomyiia sp.

1

                       

Table 6-1 continued
1997 Millbrook Marsh Benthic Macroinvertebrates (Brooks et al. 1998)

July 1997

October 1997

 

Thompson Run

Slab Cabin Run

 

Thompson Run

Slab Cabin Run

 

1

5

6

2

3

4

 

1

5

6

2

3

4

Simuliidae

143

103

72

2

138

5

 

67

65

113

8

55

24

Tabanidae                        

1

Chrysops sp.          

6

             
Tipulidae                          
Antocha sp.  

2

4

44

4

3

 

1

 

2

16

28

7

Tipula sp.              

1

2

   

2

1

Coleoptera                          
Dytiscidae                          
Agabus sp.  

1

                     
Elmidae                          
Dubiraphia sp.      

2

 

1

       

7

3

6

Optioservus sp.      

7

1

42

       

36

2

5

Stenelmis sp.      

2

 

14

       

2

   
Psephenidae                          
Ectopria sp.          

1

         

1

 
Psephenus sp.      

21

 

1

       

15

   
Hemiptera                    

1

   
Corixidae                          
Trichocorixa                      

1

 
Crustacea                          
Amphipoda                          
Gammaridae                          
Gammarus minus

2

9

3

 

3

     

2

3

 

2

 
Talitridae                          
Hyalella azteca          

6

             
Decapoda                    

1

   
Isopoda                          
Asellidae                          
Asellus sp.      

6

 

8

   

1

 

19

9

12

Turbellaria              

2

       

9

Tricladida                          
Planariidae

1

5

 

2

 

1

             

Table 6-1 continued
1997 Millbrook Marsh Benthic Macroinvertebrates (Brooks et al. 1998)

 

July 1997

 

October 1997

 

Thompson Run

Slab Cabin Run

 

Thompson Run

Slab Cabin Run

 

1

5

6

2

3

4

 

1

5

6

2

3

4

Cura foremanii  

2

               

47

   
Hymanella retenuova  

10

1

                   
Oligochaeta

14

18

23

 

3

10

 

11

11

13

1

15

155

Gastropoda                

3

       
Basommatophora                          
Physidae          

1

     

1

 

1

2

Planorbidae

2

1

             

2

     
Bivalvia                          
Veneroida  

3

                     
Pisidiidae                        

9

Pisidium sp.

1

                   

2

 
Total

300

304

305

302

308

300

 

301

317

306

300

305

305

Species Richness

11

17

11

16

10

21

 

8

9

10

19

19

18

The earliest of the historical data found for benthic macroinvertebrate communities was a survey conducted in 1978 (Miller 1979). Station 2 was on Thompson Run just below East College Avenue. Station 2 had a community characteristic of organic pollution. There were only 8 taxa, with high numbers of midges and snails and no stoneflies, mayflies or caddisflies. Station 1, also Thompson Run, was located upstream of Millbrook Marsh and had similar taxa to Station 2. This station was upstream of the sewage treatment plant discharge, and for this reason, the structure of the macroinvertebrate community, at Station 1 at least, can most likely be attributed to stormwater runoff. Station 4 was on Slab Cabin Run just above the Thompson Run confluence. There was good species diversity and a high number of pollution sensitive species. There were 19 taxa collected from Slab Cabin Run. Table 6-2 shows the benthic macroinvertebrates collected on July 11, 13 and 19, 1978 from Stations 1 and 2 of Thompson Run and Station 4 of Slab Cabin Run.

Table 6-2
1978 Millbrook Marsh Qualitative Benthic Macroinvertebrates
(Miller 1979)

 

July

 

Thompson Run

Slab Cabin Run

 

Station 1

Station 2

Station 4

Turbellaria      
Turbellaria sp.

P

   
Annelida      
Oligochaeta sp.

P

P

P

Isopoda      
Asellus    

P

Amphipoda      
Gammarus

P

   
Decapoda      
Astacidae sp.    

P

Ephemeroptera      
Ephemerella      
Stenacron    

C

Heptagenia    

C

Tricorythodes    

P

Paraleptophlebia    

P

Baetis    

C

Trichoptera      
Hydropsyche    

P

Cheumatopsyche      
Coleoptera      
Elmidae sp.    

C

Optioservus    

C

Stenelmis      
Psephenus    

P

Diptera      
Antocha      
Empididae sp.  

P

 
Simulidae sp.    

P

Muscidae      
Tipula    

P

Chironomus

P

A

 
Diamesa      
Pseudoiamesa      

Table 6-2 continued
1978 Millbrook Marsh Qualitative Benthic Macroinvertebrates
(Miller 1979)

 

July

 

Thompson Run

Slab Cabin Run

 

Station 1

Station 2

Station 4

Cricotopus

P

P

P

Diamesa

P

   
Cardiocladius  

P

 
Pentaneurini  

P

P

Eukiefferiella  

P

 
Polypedlium Fallax    

P

Polypedlium sp. 2    

P

Gastropoda      
Physa

A

P

P

Lymnae

P

   
Species Richness

8

8

19

P = present C = common A = abundant

The PennDOT macroinvertebrate surveys took place in May 1980. Some of the historical data collected for the Mt. Nittany Expressway Environmental Impact Statement included inventories by D. Reinhold of the Pennsylvania Fish Commission in 1959, and G. Miller of the Pennsylvania Department of Environmental Resources in 1978 (PennDOT 1981). Both collection sites, Reinhold’s 1959 Station 12, and Miller’s 1978 Station 27, were in the same general vicinity on Slab Cabin Run as PennDOT’s 1980 Station 3. In 1959, the invertebrates included 3 genera of stoneflies, mayflies of the genus Stenonema, and caddisflies, all pollution intolerant species (Reinhold 1959). The 1978 data included 19 species that were indicative of good stream conditions, though again, as with the fish inventory, they were warm water species rather than cold, as the stream is classified. As in 1959, there were pollution sensitive taxa present (Miller 1979). The May 1980 invertebrate collection also included 4 pollution sensitive taxa. The sample from station 3 with the highest species count and the highest diversity index of 2.63 had 22 species and was taken from a riffle with rock substrate.

Station 27 of 1978 was near the 1980 Station 4 and included 4 pollution sensitive taxa. The sample from Station 4 at the riffle had the highest diversity index of 3.89 (PennDOT 1981). Table 6-3 shows the taxa collected on May 14, 1980 from riffles and pools in Slab Cabin Run upstream of the Thompson Run confluence (PennDOT 1981).

Table 6-3
1980 Millbrook Marsh Benthic Macroinvertebrates (PennDOT 1981)

 

Slab Cabin Run

 

Station 3

Station 4

 

Riffle

Pool A

Pool B

Riffle

Pool A

Pool B

Ephemerella spp.

2

1

 

64

14

6

Baetus spp.

10

2

5

55

69

17

Simulium spp

2

   

8

3

1

Chironomidae pupae

12

5

4

14

18

10

Chironomidae larvae      

8

 

12

Stenelmis spp.

1

   

13

9

1

Cheumatopsyche spp.

5

   

40

5

1

Nematoda

2

 

1

2

8

1

Acari spp.

1

   

1

   
Antocha spp.

3

 

2

21

2

 
Stenonema ithaca    

1

4

2

2

Dolichopodidae        

2

 
Psephenus hericki      

11

1

 
Ephenerela spp.      

1

   
Tanypodinae    

1

     
Aquatic oligochaete w/o capilliform chaeta

8

 

12

     
Aquatic oligochaete with capilliform chaeta

4

 

3

     
Orthocladius spp.  

2

6

72

31

32

Orthocladinae    

1

 

29

 
Limnodrilus cerxix    

1

     
Limnodrillus hoffmeisteri

2

 

6

     
Polypedilum spp.

1

1

1

8

   
Microtendipes spp.    

1

     
Tanytarsus spp.

6

1

 

8

   
Chironomini

1

   

16

 

4

Cricotopus spp.

97

70

34

     
Conchapelopia spp.

1

     

8

 
Stenacron spp.      

1

1

2

Symphitopsyche spp.

1

   

21

2

1

Paraleptaphlebia spp.      

2

   
Nardidae (Pristina)

66

95

317

28

201

57

Paralauterborniella  

1

       

Table 6-3 continued
1980 Millbrook Marsh Benthic Macroinvertebrates (PennDOT 1981)

 

Slab Cabin Run

 

Station 3

Station 4

 

Riffle

Pool A

Pool B

Riffle

Pool A

Pool B

Eukietferiella      

8

   
Tubificidae w/o capilliform chaeta        

9

3

Phaenopsectra spp.  

1

       
Asellus spp.

1

         
Hydroptila spp.

1

   

1

   
Polycentropis spp.

1

         
Trichoptera pupae  

1

       
Psychomylidae  

1

       
Pseudochironomus    

1

     
Dubiraphia spp.        

1

 
Trichladida      

1

   
Cryptochironomus        

8

 
Hydropsyche      

2

   
Isoperia      

1

   
Psychamyia      

5

   
Brachycentrus      

4

   
Taxa per sq. ft.

22

12

17

28

20

15

Diversity (Simpson’s) Index

3.71

2.36

1.55

10.80

3.76

4.73

An important discovery was made during the mid 1980s on the effects of migration of the macroinvertebrate Gammarus minus on population structure (Miller 1985). The study site consisted of the first 19.2 m of Thompson Run. The rare crustacean Stygobromus stellmacki was found along with only several other taxa (Table 6-4). This portion of Thompson Run receives little or no stormwater and had a constant water temperature of 9.5 - 10.0° C throughout the year. The streambed habitat consisted of sand, gravel and large moss (Amblystegium noterophilum) covered rocks. Collections occurred in September and December, 1983, and April and June, 1984.

Table 6-4
List of benthic taxa collected from Thompson Run in 1983 and 1984
(Miller 1985)

Platyhelminthes
Turbellaria
Phagocata gracilis (Haldeman)
Annelida
Oligochaeta
Hirudinae
Helobdella stagnalis (Linnaeus)
Arthropoda
Crustacea
Stygobromus stellmacki (Holsinger)
Gammarus minus (Say)
Insecta
Chironimidae
Tabanidae
Mollusca
Gastropoda
Gryaulus sp.
Lymnaea sp.
Physa sp.

_______________________________________________________

In December 1987 benthic macroinvertebrates were sampled again along Spring Creek and its tributaries (Bureau of Water Quality Management 1988). Results from the collection were available for one station in Millbrook Marsh on Slab Cabin Run below the confluence with Thompson Run. Of the 6 stations that were surveyed, the Slab Cabin Run station had the lowest number of taxa and the lowest abundance of mayflies, as well as the highest proportion of true flies. The benthic macroinvertebrate species found in Slab Cabin Run on December 10 and 11, 1987 are in Table 6-5.

The most recent of the historical data was gathered in July, 1989, after the 1983 cessation of the sewage treatment plant effluent discharge into Thompson Run. Station SCR3 was approximately 0.8 km (1/2 mi) upstream from Thompson Run and station TR was on Thompson Run just below East College Avenue. The Slab Cabin Run Station collection had 23 taxa and was dominated by mayflies, aquatic beetles and midges, with several pollution sensitive mayfly and caddisfly species (Table 6-5). The Thompson Run collection had only 6 taxa with very few individuals even though the water chemistry was similar to that of Slab Cabin Run. The stream was limestone influenced, therefore very alkaline, and the dominant taxa was Gammarus, which is a limestone loving species. Hughey stated that "It looked like toxic stormwater runoff or poor substrate was limiting the community" (Hughey 1990, p. 4).

Table 6-5
1987-89 Millbrook Marsh Qualitative Benthic Macroinvertebrates
(Bureau of Water Quality Management 1989 and Hughey 1990)

 

December 1987

July 1989

 

Slab Cabin Run

Slab Cabin Run

Thompson Run

 

Station 15

Station SCR3

Station TR

Turbellaria      
Planaridae  

P

 
Annelida      
Oligochaeta sp.

P

P

P

Tubificidae  

P

 
Isopoda      
Asellidae  

P

 
Amphipoda      
Gammarus    

D

Decapoda      
Cambaridae  

P

P

Ephemeroptera      
Baetidae      
Beatis  

P

 
Ephemerella

R

P

 
Heptagenia  

(D)

 
Heptagenia  

P

 
Stenacron  

P

 
Stenonema  

P

 
Trichoptera      
Hydropsyche

R

   
Ceratopsyche bifida

P

P

 
Ceratopsyche slossonae  

P

 
Hydropsyche betteni  

P

 
Cheumatopsyche

P

   
Philopotamiidae Chimarra  

P

 

Table 6-5 continued
1987-89 Millbrook Marsh Qualitative Benthic Macroinvertebrates
(Bureau of Water Quality Management 1989 and Hughey 1990)

 

December 1987

July 1989

 

Slab Cabin Run

Slab Cabin Run

Thompson Run

 

Station 15

Station SCR3

Station TR

Coleoptera      
Elmidae      
Stenelmis

R

P

 
Optioservus

R

   
Psephenus  

D

 
Diptera      
Antocha

P

   
Chironomidae      
Cricotopus

P

 

P

Diamesa

C

P

P

Polypedilum  

P

 
Pseudoiamesa

C

P

 
Stictochironomus  

P

 
Simulidae sp.

C

P

P

Muscidae

R

   
Tabanidae      
Chrysops  

P

 
Tipula  

P

 
Eukiefferiella

P

   
Species Richness

14

23

6

P = present C = common A = abundant D = dominant

A comparison of the benthic macroinvertebrate data for 1980 and 1997 shows a decline in species richness, but a slight increase in diversity. The discrepancy in comparing the data is that the 1980 samples were taken from Upper Slab Cabin Run only, above the confluence with Thompson Run. The 1997 samples were taken from both Upper and Lower Slab Cabin Run. The 1997 Thompson Run macroinvertebrate samples are quite different from Slab Cabin Run samples both of 1980 and 1997 (Table 6-6). The average species richness was 11 and average diversity index was 2.86. The average species richness in Slab Cabin Run decreased from 19 in 1980 to 17 in 1997, though the average diversity index went from 4.49 to 4.86, which indicates slightly better diversity. Simpson’s index, l, will be lower with higher diversity, and average l in Slab Cabin Run also decreased from 0.317 in 1980 to 0.238 in 1997, showing higher diversity. Though the species richness was different in the three groups, Slab Cabin Run 1980, Slab Cabin Run, 1997, and Thompson Run 1997, the average number of individuals was essentially the same at 299, 303, and 303 respectively.

Table 6-6
Millbrook Marsh Benthic Macroinvertebrate Diversity, 1980 and 1997

 

N

s

l=Sni(ni-1)
N(N-1)

Ds=1-l

ds=1/l

Slab Cabin Run          
May 1980          
Station 3 Riffle

228

22

0.270

0.730

3.71

Station 3 Pool A

181

12

0.423

0.577

2.36

Station 3 Pool B

397

17

0.646

0.354

1.55

Station 4 Riffle

420

28

0.084

0.916

10.80

Station 4 Pool A

423

20

0.266

0.734

3.76

Station 4 Pool B

150

15

0.212

0.788

4.73

July 1997          
Station 2

302

16

0.220

0.780

4.55

Station 3

308

10

0.316

0.684

3.17

Station 4

300

21

0.299

0.701

3.34

October 1997          
Station 2

300

19

0.107

0.893

9.38

Station 3

305

19

0.184

0.816

5.42

Station 4

305

18

0.301

0.699

3.32

Thompson Run          
July 1997          
Station 1

300

11

0.338

0.662

2.96

Station 5

304

17

0.305

0.695

3.27

Station 6

305

11

0.344

0.656

2.90

October 1997          
Station 1

302

8

0.354

0.646

2.83

Station 5

308

9

0.430

0.570

2.33

Station 6

300

10

0.348

0.652

2.87

 l=Sni(ni-1) Simpson dominance
N(N-1)
Ds=1-l
Simpson diversity
ds=1/l inverse of l
s
= Species richness
N = Total number of individuals

In a healthy macroinvertebrate community, the most dominant taxon should amount to less than 20% of the total community (Brooks et al. 1998). In only two samples was this the case, in October 1997 Station 2 on Slab Cabin Run, where Ceratopsyche sp. was 19% of the total individuals and 1980 Station 3 Riffle where Orthocladius spp. made up 17% (Table 6-7). In 1980, the average of the most dominant taxa was 46%. In 1997, the average in Slab Cabin Run was 39% and the average in Thompson Run was 51%. This indicates an unbalanced community in all three groups. Table 6-7 shows the most dominant taxa for each station and its percentage of the total community.

Table 6-7
Percent Dominant Taxa in 1980 and 1997 Millbrook Marsh Macroinvertebrate Communities

Sample Most Dominant Taxa

Percent of Total Community

1980 Slab Cabin Run    
Stn. 3 Riffle Cricotopus spp.

43%

Stn. 3 Pool A Nardidae (Pristina)

52%

Stn. 3 Pool B Nardidae (Pristina)

80%

Stn. 4 Riffle Orthocladius spp.

17%

Stn. 4 Pool A Nardidae (Pristina)

48%

Stn. 4 Pool B Nardidae (Pristina)

38%

July 1997 Slab Cabin Run
Stn. 2 Ceratopsyche sp.

41%

Stn. 3 Simuliidae

45%

Stn. 4 Chironomidae

52%

Oct. 1997 Slab Cabin Run
Stn. 2 Ceratopsyche sp.

19%

Stn. 3 Chironomidae

28%

Stn. 4 Oligochaeta

51%

July 1997 Thompson Run
Stn. 1 Simuliidae

47%

Stn. 5 Chironomidae

43%

Stn. 6 Chironomidae

52%

Oct. 1997 Thompson Run
Stn. 1 Chironomidae

52%

Stn. 5 Chironomidae

64%

Stn. 6 Chironomidae

45%

It is somewhat difficult to draw conclusions from the data since the 1980 samples were taken only above the confluence with Thompson Run, and there is no historical quantitative data available for Thompson Run. The probability is fair that Thompson Run and Slab Cabin Run below the confluence have improved in some ways since 1980 due to the cessation of sewage treatment plant effluent input. On the other hand, stormwater input has been steadily increasing. The condition of the macroinvertebrate communities in Slab Cabin Run of 1980 reflects stormwater input. At best, the 1997 condition shows only slight improvement. The condition of macroinvertebrate communities in Thompson Run in 1997 most likely reflects the higher level of stormwater input compared to Slab Cabin Run. The moderate degradation of the streams in Millbrook Marsh and their aquatic communities will probably decline further if the volume of incoming stormwater increases or the water quality declines (Brooks et al. 1998).

Wetland Macroinvertebrates

Macroinvertebrate fauna was collected on July 11, 1997 in Thompson Run backwater pools and the saturated sediments adjacent to the stream (R. Bennett, pers. comm.). On July 3, 1997 the macroinvertebrate collection occurred in ephemeral pools and saturated sediments of the Farm 12 wetland site. The total number of individuals was calculated by multiplying a 25% subsample by 4. The reason for subsampling was due to the overwhelming abundance of some taxa. Taxa richness was calculated only to the family level because some specimens were only taken to that level.

The most dominant taxa in all 4 samples exceeded 20% of the total community for that sample. The most drastic was the Farm 12 pool sample, in which Mesogastopoda Hydrobiidae made up 83%, followed by Chironomidae in the Thompson Run stream sample which made up 62%. An unbalanced community is indicated by all 4 samples The macroinvertebrate species richness of Thompson Run soil is substantially lower than that of the Farm 12 soil. In addition, there were only 6 individuals total in the Thompson Run soil. This could be because of a lower quality habitat due to deposits from stormwater or because of contamination making the soil uninhabitable.

Table 6-8
1997 Millbrook Marsh Wetland Macroinvertebrates Reference Wetland Site #56 and #57
(Bennett 1998)

 

# 57 Thompson Run

# 56 Farm 12

 

Stream

Soil

Pool

Soil

Insecta        
Collembola        
Isotomidae    

4

 
Ephemeroptera        
Baetidae        
Baetis sp.

15

     
Odonata        
Coenagrionidae        
Enallagma sp.

3

     
Hemiptera        
Corixidae

28

     
Hesperocorixidae sp.

3

     
Trichoptera        
Hydroptilidae

3

 

40

 
Hydroptila sp.

5

     
Limnephilidae        
Limnephilus sp.    

3

 
Diptera        
Ceratopogonidae  

1

   
Bezzia sp    

10

 
Chironomidae

2208

1

111

10

Muscidae

3

     
Psychodidae        
Pericoma sp.      

7

Sciomyzidae

2

     
Simuliidae

330

2

 

1

Tipulidae        
Molophilus sp.    

1

 
Paradelphomyia sp.      

1

Tipula sp.      

3

Table 6-8 continued
1997 Millbrook Marsh Wetland Macroinvertebrates Reference Wetland Site #56 and #57
(Bennett 1998)

 

# 57 Thompson Run

# 56 Farm 12

 

Stream

Soil

Pool

Soil

Coleoptera        
Dytiscidae        
Agabus sp.

2

1

   
Nebrioporus sp.*

3

     
Helorphidae        
Helophorus sp.    

50

 
Hydrophilidae        
Laccobius sp.

3

     
Crustacea        
Amphipoda        
Gammaridae        
Gammarus sp.    

527

 
Podocopa

541

 

303

8

Arachnida        
Acariformes

4

 

7

1

Oligochaeta

134

1

 

24

Gastropoda        
Mesogastopoda        
Hydrobiidae*    

5138

55

Basommatophora        
Lymnaeidae

143

     
Physidae

84

     
Planorbidae

4

   

1

Bivalvia        
Veneroida        
Sphaeriidae

70

 

15

86

Total no.

3588

6

6209

197

Taxa richness

18

5

12

11

*awaiting taxonomic confirmation from examination against reference specimens.

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