amazon benthic report april 2009

Assessment of Global Vision

International’s Impact on Water Quality

in the Bosque Protector Yachana

Preliminary Report

12 April 2009

Authors

Jonathan Escolar, Andrew Mercer, Hannah Urpeth

Table of Contents

Summary……………………………………………………………………………………………………………………………….ii

1.0 Introduction……………………………………………………………………………………………………………….1

2.0 Methods…………………………………………………………………………………………………………………….2

2.1 Site selection…………………………………………………………………………………………………….....2

2.2 Collection………………………………………………………………………………………………………………2

2.3 Identification…………………………………………………………………………………………………………2

2.4 Analyses………………………………………………………………………………………………………………..3

2.4.1 EPT Index…………………………………………………………………………………………….....3

2.4.2 Sensitivity Index………………………………………………………………………………………3

3.0 Results……………………………………………………………………………………………………………………….4

3.1 Upper Pump Stream……………………………………………………………………………………………..4

3.2 Lower Pump Stream……………………………………………………………………………………………..4

3.3 EPT Combined Results…………………………………………………………………………………………..4

3.4 Sensitivity Combined Results…………………………………………………………………………………5

4.0 Discussion…………………………………………………………………………………………………………………..6

5.0 Conclusions and Recommendations……………………………………………………………………………7

References…………………………………………………………………………………………………………………………….7

Acknowledgements……………………………………………………………………………………………………………….8

Appendix I……………………………………………………………………………………………………………………………..8

ii

Summary

This document is a preliminary report investigating the water quality of a stream directly impacted by

GVI’s presence in the Bosque Protector Yachana using benthic macro invertebrates as indicators. The

results show that water quality upstream is marginally better than that downstream, suggesting that the

effluents released by GVI have negatively affected water quality. However, two different analyses gave

different results, causing uncertainty as to which gives a true reflection of water quality. Further

investigation and consultation with local experts has revealed that the BMWP/Col index is a more

reliable way of determining water quality in this region. Recommendations for the future direction of

this investigation include:

1. Resample the same sites using the BMWP/Col index.

2. Use kick nets in combination with Surber nets to sample areas of deeper water in streams as

well as riffle sites.

3. Take more samples to obtain a large enough dataset to test statistically.

4. Sample the same areas long term to account for seasonal variation.

1

1.0 Introduction

GVI has been using a research station based in the Bosque Protector Yachana in Napo Province, Ecuador

for approximately three years. The infrastructure of the site unfortunately lacks a proper grey water

system, and instead waste water from sinks and showers is drained into a large wooden-sided

subterranean tank where it gradually seeps into an adjacent waterway. Chemicals used on the site and

therefore released into the ecosystem include bleach, detergent, DEET, laundry soap and other personal

hygiene products. Fecal matter from toilets is contained in a similar tank and therefore must also slowly

leach into the surrounding soil and waterways. Figure 1.0 shows the layout of GVI base camp in relation

to the impacted waterways.

Figure 1.0 Map showing position of grey water and sewage tanks in relation to Pump Stream.

Two study sites were investigated that represented two different treatments: One pre-discharge

(sample site 2), that is not impacted by wastewater from GVI Base Camp and a second post-discharge

(sample site 1), located downstream from GVI and therefore exposed to any effluents. It is therefore

expected that sample site two, the upper Pump Stream, will have higher water quality as it is not

impacted by effluents discharged by GVI Base Camp.

Sampling benthic invertebrate communities is a reliable and economical way of determining water

quality (Feinsinger, 2001). Each invertebrate family has differing sensitivities to contaminants, and their

presence or absence as well as abundance can be used in different analytical indices to give an

2

indication of water quality. Over 50 different methods have been developed for the biological

assessment of water quality in temperate countries (Cota et. al., 2002) and some have been adapted for

use in tropical regions and their associated biota. The analyses selected for this investigation are

discussed fully in subsequent sections.

2.0 Methods

2.1 Site selection

Two study sites were selected, each representing a different treatment. One site was located before

waste water from the base camp entered the water system (upper Pump stream) and the other site

selected in an area downstream to where waste water was discharged (lower Pump stream). Study sites

were selected based on the presence of areas of fast flowing shallow water over rocky substrate known

as riffles. Valid study sites contained riffles of both suitable size and abundance to allow for the

collection of 30 samples to be taken from the selected study area.

2.2 Collection

Samples were collected by employing a modified kick sampling technique (Sutherland, 1996) with the

use of a Surber net (300mm x 300mm). The Surber net was placed upon the substrate of identified

riffles with the net positioned downstream, allowing for the collection of dislodged individuals. The area

of each sample was defined by the frame of the Surber net resting on the substrate, and all loose stones

within it were hand scrubbed before being placed outside of the sample area and the remaining

substrate disturbed thoroughly by hand to a depth of one inch. After the sample was completed any

removed stones were placed back in their original position so as to minimize disturbance.

After each sample, the contents of the Surber net were emptied into a large bucket with the net being

thoroughly flushed with stream water and then visually checked for remaining specimens. Collected

materials from the sample were divided into trays and searched for specimens with any individuals

found being removed with tweezers and placed in a killing jar containing 70% alcohol. A separate killing

jar was used for case-crafting Trichoptera to aid in the identification process.

The above process was repeated until 15 samples from each survey site were collected. A further 15

samples were taken at later dates from both the upper and lower Pump Stream.

2.3 Identification

Collected specimens were taken back to the field base and using a taxonomic key (Reyes & Peralbo,

2001) identified to family level before being tallied. Identification was performed using 10x hand lenses.

3

2.4 Analyses

Tallied results were then used in conjunction with both Ephemeroptera-Plecoptera-Trichoptera (EPT)

index and an individual sensitivity index (Reyes & Peralbo, 2001) to determine water quality for the

selected study areas.

2.4.1 EPT Index

The EPT index measures the percentage of individuals from the orders Ephemeroptera, Plecoptera and

Trichoptera against the total number of individuals in each sample. These three orders are used as they

are particularly sensitive to changes in water quality. The higher the percentage on this index, the higher

the quality of the water. Table 2.0 shows how the scores relate to water quality.

EPT Total Water quality

75 - 100% Very Good

50 - 74% Good

25 - 49% Moderate

0 - 24% Poor Table 2.0 EPT Index scores.

2.4.2 Sensitivity Index

This index works on the presence or absence of different orders, sub orders or families that each have a

different degree of sensitivity to contaminants. Each group is assigned a value of 1 - 10, the groups given

a rating of 10 being the most sensitive and the ones rated 1, least sensitive. The score from the groups

present is added up and higher scores indicate a higher quality of water. Table 2.1 shows the values

given to each group.

Sensitive Species Total Water quality

101 - 145+ Very Good

61 – 100 Good

36 – 60 Moderate

16 – 35 Poor

0 – 15 Very Poor Table 2.1 Sensitivity Index scores.

4

3.0 Results

3.1 Upper Pump Stream

The upper Pump Stream was sampled on two occasions, 25.02.2009 and the 04.03.2009. Each time, 15

Surber net samples were collected from different locations. Table 3.1 shows the results for water quality

from each sample day and a mean value for both on the EPT and Sensitivity indices. In all three the

water quality is rated as moderate by the EPT index and very good on the sensitivity index.

Sample EPT index score Sensitivity index score

25.02.2009 43.35 130

04.03.2009 34.81 109

Mean 39.08 119.5 Table 3.1 Water quality results for upper Pump Stream on EPT and Sensitivity indices.

3.2 Lower Pump Stream

The lower Pump Stream was also sampled on two occasions, 23.02.2009 and the 17.03.2009. Again, 15

Surber net samples were taken from individual locations on each sampling date. Table 3.2 shows the

results for water quality from each sample day and a mean value for both indices. According to the EPT

index water quality is poor in the sample taken on 23.02.2009, and moderate on both the 17.13.2009

and on average. On the Sensitivity index it is rated as very good for all three samples.

Sample EPT index score Sensitivity index score

23.02.2009 22.95 123

17.03.2009 29.35 143

Mean 26.15 133 Table 3.2 Water quality results for lower Pump Stream on EPT and Sensitivity indices.

3.3 EPT Combined Results

Results from the EPT index support the null hypothesis that water quality is higher in the upper Pump

Stream. Figure 3.1 shows the EPT scores from the upper and lower Pump Stream on both sample dates

and a mean score of the two.

5

Figure 3.1 EPT scores for upper and lower Pump Stream on each sample date and mean score.

3.4 Sensitivity Combined Results

The results from the Sensitivity index analysis do not support the null hypothesis. Instead they indicate

that on average water quality is marginally higher in the lower Pump Stream. Figure 3.2 shows the

Sensitivity index scores from the upper and lower Pump Stream on both sample dates and their mean.

Table 3.2 Sensitivity index scores for upper and lower Pump Stream on each sample date and mean score.

6

4.0 Discussion

The major surprise presented by the results of this study is that the EPT index and Sensitivity index gave

contradicting results for all the samples collected. The values obtained from the EPT index fit the null

hypothesis that water quality is higher on the upper Pump Stream, although the sample size is too small

to test for a significant difference statistically. With the Sensitivity index however, water quality was on

average higher in the lower Pump Stream, although again, the sample size was not large enough to test

for significant differences.

The reason for this disparity is that the analyses used are unsuitable for the Neotropical region, despite

the fact that these were taken from a source designed for use in Ecuador by Ecuadorians (Reyes &

Peralbo, 2001). The use of the EPT index gives unreliable results because the number of families of

stoneflies (Plecoptera) drops off to just one, Perlidae, the closer one is to the equator (Feinsinger, 2001).

After further research and consultation a more suitable analysis was found for the Neotropics, the

BMWP/Col index (Contreras et. al.,2008; Zarate, pers. comm., 2009) that uses more relevant families as

sensitivity indicators.

The use of the Sensitivity index is also questionable because unlike the EPT index it does not take

abundance into account. This could affect the accuracy of results as some samples yield substantially

more individuals than others. For example, the 17.03.2009 sample consisted of 620 individual

invertebrates, whereas the other three samples had a mean of 173 individuals. It should be noted

however, that the BMWP/Col index also ignores abundance and works solely on presence or absence of

families. The identification key provided by Reyes and Peralbo (2001) also limited the accuracy of the

study as a large proportion of the invertebrates collected could only be identified as ‘other’. A new key

(Contrera, et. al., 2008) that enables identification of a greater number of families will be used for future

studies.

The use of the Surber net to sample riffles was effective, although other studies have found kick nets to

yield better and more cost-effective results (Buss & Borges, 2008). A combination of the two methods

would enable sampling of both riffles and pools and may give a more complete sample of benthic

invertebrate assemblages.

Some other physical factors that may affect the lower Pump Stream and potentially skew results have

been noted. First, a landslide has blocked the flow of the stream in one area creating a large, still body

of water. The flow then returns to normal but the 17.03.2009 sample was taken downstream from this

site as there were not enough suitable riffles higher up the waterway. A road is also in close proximity to

a stretch of the lower Pump Stream, and although the level of traffic is low, runoff could potentially have

an impact on water quality.

Another factor that must be addressed in future studies is non-use of weather data in correlation with

these data. Precipitation levels can have a significant effect on benthic macro invertebrate communities,

as many may be washed away after periods of heavy rainfall. There was particularly heavy rainfall prior

to surveying the upper Pump Stream on the 04.03.2009 that may have washed away a significant

number of the invertebrates present.

7

5.0 Conclusions and Recommendations

The main conclusion drawn from this investigation is that the analyses used were unreliable at giving an

accurate reflection of water quality as they are unsuited to Neotropical freshwater habitats. The sample

sites should be re-sampled and analysed using the BMWP/Col index and a more detailed identification

key, and deeper water areas should be sampled using kick nets in addition to the sampling of riffles with

Surber nets. Moreover, a greater number of samples should be taken to allow a statistical analysis of the

samples to be carried out. Ideally this should be conducted at regular interval throughout the year to

look for seasonal variations and these data should be correlated with weather data.

As the water quality results are unreliable the authors are unable to make recommendations regarding

changes to GVI practice and infrastructure.

References

Buss D. F. & Borges E. L., 2008. ‘Application of Rapid Bioassessment Protocols (RBP) for Benthic

Macroinvertebrates in Brazil: Comparison between Sampling Techniques and Mesh Sizes.’ Neotropical

Entomology 37 (3): 288-295

Contreras J., Roldán G., Arango A. & Álvarez L.F., 2008. ‘Evaluación de la calidad del agua de las

microcuencas La Laucha, La Lejía y La Rastrojera, utilizando los macroinvertebrados como

bioindicadores, Municipio de Durania, Departamento Norte de Santander, Colombia.’ Rev. Acad.

Colomb. Cienc. 32(123): 171-193

Cota, L., Goulart, M., Moreno, P. & Callisto, M. ‘Rapid assessment of river water quality using an adapted

BMWP index: a practical tool to evaluate ecosystem health’. Verh. Internat. Verein. Limnol. 28: 1-4

Feinsinger, P. (2001) Designing Field Studies for Biodiversity Conservation. Island Press: Washington

Reyes , C.C & Peralbo K.F. (2001) Manual de Monitoreo: Los Macroinvertebrados Acuaticos como

Indicadores de la Calidad del Agua. EcoCiencia: Ecuador

Sutherland, W.J. (1996) Ecological Census Techniques: A Handbook. Cambridge University Press: UK

8

Acknowledgements

The authors would like to thank the following volunteers and staff who participated in the data

collection during the expedition 091b at the Bosque Protector Yachana: Katherine Allison, Chris Beirne,

Karina Berg, Sophie Cousins, Max Hardman, Amy Hill, Thomas Keating, Victoria Morgan-Hill, James Pitt,

Alan Rea, Rachel Reisinger, Piter Silvera, Glen Skelton, Natalie White, Mauro Yumbo.

Appendix I

This appendix contains the data sheets from each sample date.

Ephemeroptera/Plecoptera/Trichoptera (EPT) Index & Sensitive Species Index

Survey Site Upper pump stream - 1st section

Date 25/02/09 Name of Surveyor/s Katherine, Hannah, Jon, Max, James, Natalie, Amy

Classification

Phylum / Class Order Family

Abundance

EPT Present

Sensitive Species

Annelida Hirudinea Glossiphonidae

0

0

Oligochaeta Annelidae

0

0

Tubificidae

Aracnida Acari Hydrachnidae

0

0

Crustacea Decapoda Palaeomonidae 2

0

0

Pseudothelpusidae

Gammaridea Hyalellidae

Insecta Coleoptera Chrysomelidae

Elmidae (Adult) 4

0

6

Elmidae (Larva) 1

0

6

Gyrinidae

Psephenidae

0

0

Ptilodactylidae

(Larva) 39

0

10

Scarabidae

Diptera Caratopogonidae

0

0

Chironomidae 4

0

2

Ephydridae

Simuliidae

10

0

8

Stratiomyidae

Syrphidae

Tipulidae

12

0

3

Ephemeroptera Baetidae

0

0

Euthyplocidae 2

2

9

Leptohyphidae

0

0

Leptophlebiidae 55

55

9

Oligoneuridae

0

0

Other

2

2

0

Hemiptera Belostomidae

Naucoridae

11

0

7

Veliidae

0

0

Lepidoptera Pyralidae

0

0

Neuroptera Corydalidae

3

0

6

Odonata Anisoptera

9

0

8

Gomphidae

Libellulidae

Zygoptera

26

0

8

Calopterygidae

Coenagrionidae

9

Plecoptera Perlidae

18

18

10

Other

0

0

Trichoptera Calamoceratidae

Glossosomatidae 3

3

7

Helicopsychidae

Hydrobiosidae 8

8

9

Hydropsychidae 4

4

5

Lampyridae

Leptoceridae 5

5

9

Odontoceridae

Philopotamidae 13

13

8

Polycentropodidae

Other

4

4

0

Mollusca Bivalvia Sphaeridae

0

0

Gastropoda Hydrobiidae

4

Physidae

Planorbidae

Other

0

0

Nematomorpha Nematoda Gordioidea

0

0

Platelminta Tricladia Planarida

9

0

0

Other (excluding EPT)

15

0

0

Total

263

114

130

EPT Total

43.35

Sensitive Species Total

130


Survey Site Upper Pump Stream - Upstream from Access C

Date 4/3/2009 Name of Surveyor/s Andy M, Chris, Glen, Victoria, Rachel, Max, Dan, Piter

Classification


Abundance

EPT Present

Sensitive Species


0

0


0

0

Tubificidae

Aracnida Acari Hydrachnidae 2

0

10 Crustacea Decapoda Palaeomonidae 5

0

0

Pseudothelpusidae



Elmidae (Adult) 3

0

6

Elmidae (Larva)

0

0

Gyrinidae

Psephenidae

0

0

Ptilodactylidae

(Larva) 17

0

10

Scarabidae

Diptera Caratopogonidae 1

0

3

Chironomidae 11

0

2

Ephydridae

Simuliidae

8

0

8

Stratiomyidae

Syrphidae

Tipulidae

8

0

3


0

0

Euthyplocidae 4

4

9

Leptohyphidae

0

0

Leptophlebiidae 17

17

9

Oligoneuridae

0

0

Other

5

5

0


10

Naucoridae

0

0

Veliidae

0

0


0

0


2

0

6

Odonata Anisoptera

5

0

8

Gomphidae

Libellulidae

Zygoptera

24

0

8

Calopterygidae

Coenagrionidae

Plecoptera Perlidae

10

10

10

Other

0

0


Glossosomatidae

0

0

Helicopsychidae

Hydrobiosidae

0

0

Hydropsychidae

0

0

Lampyridae

Leptoceridae 2

2

9

Odontoceridae

Philopotamidae 4

4

8

Polycentropodidae

Other

5

5

0


0

0


Physidae

Planorbidae

Other

0

0


0

0


2

0

0


0

0

Total

135

47

109

EPT Total

34.81


109


Survey Site Main Pump Stream Lower - 1st Sample

Date 23/02/09 Name of Surveyor/s Hannah, Andy M, Katherine, Sophie, Alan, Natalie, Mauro

Classification


Abundance

EPT Present

Sensitive Species


0

0


0

0

Tubificidae


0

0

Crustacea Decapoda Palaeomonidae

0

0

Pseudothelpusidae



Elmidae (Adult) 5

0

6

Elmidae (Larva) 5

0

6

Gyrinidae

Psephenidae

0

0

Ptilodactylidae

(Larva) 23

0

10

Scarabidae

Diptera Caratopogonidae

0

0

Chironomidae

0

0

Ephydridae

Simuliidae

5

0

8

11

Stratiomyidae

Syrphidae

Tipulidae

5

0

3


0

0

Euthyplocidae 5

5

9

Leptohyphidae

0

0

Leptophlebiidae 3

3

9

Oligoneuridae

0

0

Other

5

5

0


Naucoridae

20

0

7

Veliidae

0

0


0

0


1

0

6

Odonata Anisoptera

8

0

8

Gomphidae

Libellulidae

Zygoptera

15

0

8

Calopterygidae

Coenagrionidae

Plecoptera Perlidae

6

6

10

Other

0

0


Glossosomatidae 3

3

7

Helicopsychidae

Hydrobiosidae 1

1

9

Hydropsychidae 1

1

5

Lampyridae

Leptoceridae 2

2

9

Odontoceridae

Philopotamidae

0

0

Polycentropodidae

Other

2

2

0


0

0


Physidae

Planorbidae

Other

0

0


1

0

3


3

0

0


3

0

0

Total

122

28

123

EPT Total

22.95


123


Survey Site Lower pump Stream (2nd Section - Road)

Date 16/3/2009 Name of Surveyor/s Hannah, Jon, Karina, Sophie, James, Tom, Dan, Mauro, Victoria

Classification


Abundance

EPT Present

Sensitive Species


0

0


11

0

1

Tubificidae


0

0

Crustacea Decapoda Palaeomonidae 2

0

0

Pseudothelpusidae



Elmidae (Adult) 7

0

6

12

Elmidae (Larva) 17

0

6

Gyrinidae

Psephenidae

0

0

Ptilodactylidae

(Larva) 20

0

10

Scarabidae

Diptera Caratopogonidae 5

0

3

Chironomidae 127

0

2

Ephydridae

Simuliidae

43

0

8

Stratiomyidae

Syrphidae

Tipulidae

19

0

3


0

0

Euthyplocidae 5

5

9

Leptohyphidae 1

1

7

Leptophlebiidae 77

77

9

Oligoneuridae

0

0

Other

21

21

0


Naucoridae

27

0

7

Veliidae

2

0

8


0

0


3

0

6

Odonata Anisoptera

27

0

8

Gomphidae

Libellulidae

Zygoptera

61

0

8

Calopterygidae

Coenagrionidae

Plecoptera Perlidae

9

9

10

Other

0

0


Glossosomatidae 7

7

7

Helicopsychidae

Hydrobiosidae

0

0

Hydropsychidae 30

30

5

Lampyridae

Leptoceridae 9

9

9

Odontoceridae

Philopotamidae 14

14

8

Polycentropodidae

Other

9

9

0


0

0


Physidae

Planorbidae

Other

2

0

3


0

0


16

0

0


49

0

0

Total

620

182

143

EPT Total

29.35


143

amazon benthic report april 2009

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