2. Presentation Outline
Introduction
Benthic Macroinvertebrates
Macroinvertebrates as Indicators
Benthic Index of Biotic Integrity (I-IBI)
Macroinvertebrates Sampling- The
Basics
Common Macroinvertebrates
References
3. Introduction
Clean water is essential to life.
Adverse changes to the water
quality of one stream can
impact all the bodies of water
downstream – rivers, lakes, or
even the ocean. When water
quality degrades, changes to
plant, invertebrate, and fish
communities may occur and
affect the entire food chain.
4. • Through water quality monitoring, communities can
assess the health of their streams and rivers over
time. Once baseline data on the health of a stream
is collected, subsequent monitoring can help
identify when and where pollution incidents occur.
• Water quality can be assessed using chemical
sampling or biological sampling.
• Biological water quality monitoring involves
collecting samples of aquatic benthic
macroinvertebrates.
5. Benthic Macroinvertebrates
(bottom-dwelling) (animals w/o backbones visible to naked eye)
Heptageniidae sp. Hydropsyche sp. Perlodidae sp.
(Mayfly larva) (Caddisfly larva) (Stonefly larva)
Macroinvertebrates are useful indicators of the health or condition of
wetlands and other water bodies. They respond to many kinds of
pollution, including chemical pollution and physical disturbance to
the landscape around the site, wetland structure, and hydrology.
There are several advantages of using macroinvertebrates.
Great candidates for biological monitoring…
8. 3 Categories of Stream Macroinvertebrates
Group 1 – pollution sensitive
(require higher DO, neutral pH, cold water)
Tolerance Index : 1-3
Ex. mayflies, stoneflies, caddisflies
Group 2 – somewhat pollution tolerant
Tolerance Index : 4-7
Ex. scuds, dragonflies, damselflies
Group 3 – pollution tolerant
(can tolerate low oxygen, lower/higher pH, warmer water)
Tolerance Index : 8-10
Ex. leeches, aquatic worms, midge larva
9. The Tolerance Index (0 – 10)
Classifies macroinvertebrates according to their sensitivity to
pollution. This is used world-wide as a means of assessing
biological assemblages .
0 10
most pollution sensitive most pollution tolerant
e.g. Stoneflies e.g. Midges & Leeches
require high DO, clear contain hemoglobin, tolerate lower DO,
water, rocky cobble prefer soft substrate, less sensitive to
substrate, not found in toxins, found them in areas with high
areas of high sedimentation sedimentation, Eutrophication and poor
or Eutrophication. water quality
10. Biological Integrity
“the ability to support and maintain a balanced,
integrated, and adaptive community of organisms
having a species composition, diversity and
functional organization comparable to those of
natural habitats within a region" *
*
(Karr,1981)
12. Benthic Index of Biotic Integrity
(B-IBI)
• Index based on macroinvertebrates samples that
integrates several parameters to produce an overall
“health score” for a given water body
Result: dose-response curves to human impact
e.g. Taxa Generalized Plot of B-IBI
richness, Scores vs. Human Impact
relative
abundance of
certain taxa,
feeding groups
er oc SI B
I
e.g. Pollution,
habitat
Human Impact
degradation,
flow alteration
13. EPA’s Suggestions for IBI Use*
• Nonpoint Source Pollution Assessment
• Watershed Protection
• Total Maximum Daily Load (TMLD) Process
• Ecological Risk Assessment
• Development of Water Quality Criteria and
Standards
* Barbour et al., 1999
14. Macroinvertebrate Sampling: The
Basics
• Identify the goal – How
will the data be used?
– Regulatory purposes
– Detect trends
– Screening purposes
– Educational programs
• The goal should guide
your sample design and
dictate your methods
16. Sample collection
1 . Qualitative: to find out different taxa, mesh size hand net are used
2.Quantitative: to find out number of organisms, abundance, density,
frequency etc., Grab sampler and Multi-Habitat Sampler(MHS) are
used.
17. • Quantitative by Multi-Habitat Sampling (MHS) approach*, this
includes 20 sampling units taken from all habitat types at the
sampling site, each with a share of at least 5 % coverage.
• A total of 20 samples are taken and a single composite sample
is prepare.
*A habitat assessment protocol for each site (ASSESS HKH project, 2006).
18. Sample processing and preservation
• stirred the sample in water filled bucket and sieve floated animals with
net of mesh size 500 micrometer.
• transferred into plastic bottles.
• label the bottle with site location and date.
• preserve at 4% formalin.
19. Sorting and Identification
• After a week of preservation in
formaldehyde.
• The sample is washed
thoroughly by using mesh size
of 0.5mm and kept in white
enameled tray.
• Animals visible with necked
eyes were picked and kept in
various petridishes depending
on various morphological forms.
• Finally the animals were
identified up to the family level
by using the key books.
Classifies macroinvertebrates according to their sensitivity to pollution For example: * Stoneflies require high DO, clear water, rocky cobble substrate to cling onto. So, they are not found in areas of high sedimenation or eutrophication. (Their absence is meaningful—at least tells us which conditions are not present). * Midges & Leeches contain hemoglobin and therefore don’t need as much oxygen in their environment. They prefer soft substrates to burrow into and have a high tolerance to toxins. Therefore, we find them in areas with high sedimentation, eutrophication and poor water quality
Foundation concept of IBI Provides reasoning for individual component metrics, most of which have to do with species composition (taxa richness, relative abundance of different taxa)
generalized plot of what we would expect to occur—IBI scores decrease with increasing human impact both are comprised of various components—IBI score is includes information about taxa richness and the types of organisms found. Human impact can encompass a wide range of measurements including impervious cover and various types of land use.
TMDL—total maximum daily load NPDES—National Pollutant Discharge Elimination System EPA suggests these uses, but can IBI scores withstand scrutiny enough to be implemented in these programs?
