bio-indicators and biomonitoring
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Bio-indicators and biomonitoring
Marinda AvenantCentre for Environmental Management
University of the Free State
31 January 2012
MOB743: Measuring biodiversityMOB743: Measuring biodiversity
Biological monitoring
The systematic use of biological responses (or ecological indicators) to measure and evaluate anthropogenic changes to the environment with the purpose of using this information in quality control programs.
The core principle of biomonitoring is to detect divergence from biological integrity (especially divergence attributable to human actions). (Karr, 1999).
Where has it all started? Measuring biological integrity
1900s Quantitative indices
Indicator sp.; guilds; sp. Richness; sp. Diversity; similarity indices etc.
Clean Water Act of 1972
Index of Biotic Integrity IBI (Karr et al., 1986) Multi-metric index Integrative ecological index that
directly relates fish communities to other biotic and abiotic components of the ecosystem.
Where has it all started? 1972 Clean Water Act (USA) mandated:
“Protection of River health… restoring and maintaining the chemical, physical and biological integrity of the Nation’s waters”.
Where has it all started? Measuring biological integrity
1900s Quantitative indices
Indicator sp.; guilds; sp. Richness; sp. Diversity; similarity indices etc.
Clean Water Act of 1972
Index of Biotic Integrity IBI (Karr et al., 1986) Multi-metric index Integrative ecological index that
directly relates fish communities to other biotic and abiotic components of the ecosystem.
Integration of land use impacts on drivers, habitats & biological responses
Louw & Kleynhans, 2007
Where has it all started? In South African context
SASS – Chutter (1972) 1990s FAII (Kleynhans, 1999) FAII takes into account:
Relative intolerances of fish species
Frequency of occurrence General health & well-
being
FRAI; MIRAI; VEGRAI
Biomonitoring of water resources required by Law
National Water Act (1998) Chapter 14 recognizes
monitoring of water resource quality as an integral part of water resources management
National Water Resources Strategy (NWRS) Need different monitoring
systems to give a comprehensive expression of the state of the environment
Concepts of “River health” and “Ecological integrity”
“River Health” concept
River health can be defined as the degree to which the three main physical & chemical attributes of a river (its energy source, water quality and flow regime), plus its biota and their habitats, match the natural conditions at all scales. (Karr, 1991)
What is Ecological Integrity?
The capability of an ecosystem to support and maintain a resilient community of organisms having a species composition, diversity, and functional organisation comparable to that of natural habitats in the region. ( Adapted from Karr & Dudley, 1981).
Ecological integrity = habitat integrity + biological integrity + physical-chemical integrity
Ecological integrity = habitat integrity + biological integrity + physical-chemical integrity
Ecological integrity
Nothing alive
Severe disturbance
Gradient of biological condition
Gradient of human disturbance
Pristine
No disturbance
Unhealthy
Not sustainable
Healthy
Sustainable
Biological integrity
Threshold(After Karr & Chu, 1999)
LOW ecological integrity HIGH ecological integrity
Can we determine ecological integrity?
Biotic integrity can also be viewed as a measure of the degree to which the present biological condition of a system has been modified relative to its natural state.
Natural state (Reference conditions)
Natural state or reference condition
Condition with no or minimal anthropogenic stress.
In the absence of ecosystems in their “natural state” the concept of “best attainable” is relevant.
Reference state = benchmark
How do we determine reference conditions?
Locate the least impacted sites, either in the same river zone or in a river that is ecologically similar.
Use results of historical surveys before human impacts, or from ecological similar rivers. Use historical photographs and land cover data.
Expert knowledge. “Ecoregions” “Virtual ecosystems”
Present ecological state
Conceptual model for assessingthe ecological state of an ecosystem (cf. RHP)
Present ecological statePresent ecological state
Present ecological state (PES) The current state of affairs! - How much does the
current state differs from the natural state Expressed in terms of the following components:
Physical integrity/Drivers Geomorphology Hydrology Physico-chemical integrity
Biological integrity/response Ecostatus
Integrated state
Description of PES
Score % Class Description
90-100 A Unmodified or approximates natural conditions closely
80-89 B Largely natural with few modification
60-79 C Moderately modified
40-59 D Largely modified
20-39 E Seriously modified
0-19 F Critically modified
Ecological categories
A
Unhealthy
Not sustainable
Healthy
Sustainable
Biological integrity
Threshold
Score % Class Description
90-100 A Unmodified or approximates natural conditions closely
80-89 B Largely natural with few modification
60-79 C Moderately modified
40-59 D Largely modified
20-39 E Seriously modified
0-19 F Critically modified
F E BCD
Tools we use?
What do you need to assess the ecological integrity of an ecosystem?
Effective tools to measure the “health” of rivers at scales large enough to be useful for management.
These tools should be comprehensive, sensitive and quantitative tools (indicators) that are able to integrate and assess the conditions of each of the mentioned components (physical, chemical & biological) of an ecosystem.
Why are chemical analyses not enough? The results reflect the
conditions at the exact time of sampling.
It is impossible to measure all different chemical substances.
Some of the most toxic substances occur in minute quantities, often below detection limits (Day, 2000).
Chemical measures cannot be assumed to reflect the health of biota.Chemical measures cannot be assumed to reflect the health of biota.
“Integrators” of information
Biological communities: Reflect overall ecological
integrity (chemical, physical & biological)
Integrate the effects of different stressors in the catchment – aggregate impact
Integrate the stresses over time & provide an ecological measure of fluctuating environmental conditions.
Patterns in community response to stress are used to
determine biological integrity & ecological function
Ecological Indicators (Tools)
The tools (indicators) used for assessing the complex variables that constitutes river health need to be:
Ecologically based Efficient Rapid Consistently applicable in
different regions
Ecological indicators (Tools)
Indicator species Resident communities (e.g. fish, invertebrates)
reflect (or integrate) chemical & physical impacts in a time-related manner, and are therefore regarded as good indicators of overall biological integrity.
Macro-invertebrates Good indicators of localised conditions Integrate effects of short-term env variations Sampling relatively easy, requires few people and
inexpensive gear Minimal detrimental effect on resident biota. Macro-invertebrates abundant in most streams.
Fish
Good indicators of long-term effects & broad habitat conditions
Fish assemblages represents various trophic levels.
Env requirements & life-history of (relatively) fish well-known
Quantitative Indices
Interpretation of results obtained by means of biomonitoring.
The information obtained by biomonitoring should be simplified to be of use to resource managers, conservationists & the public.
A biological index integrates and summarises the biological data within an indicator group.
Biological indices therefore quantify the condition of river health with a numeric output.
State of the Modder River
SASS5
The value of biomonitoring
Is it appropriate technology?
Biomonitoring is good for: Surveillance of the
general ecological state of aquatic systems
Assessment of impacts (before & after)
Audit of compliance with ecological objectives or regulatory standards
Detection of long-term trends in the environment
Biomonitoring is good for:
To integrate information…
To provide strong scientific support in the absence of a full understanding of properties and interactions of complex systems being assessed
As an element of environmental management and an NB method (tool) in determining the state of the aquatic environment.
To summarize: Biomonitoring is used to track, evaluate and
communicate change in the condition of living ecosystems as a result of human impacts.
Biomonitoring, therefore, identifies ecological risks that are NB to human health and well-being
The goal is not to document and understand ALL the variation that arises in natural systems.Limitations:
Not useful as early warning system!
Difficult to account for natural variables!
Sampling labour intensive & time-consuming!
While science thrives on good questions,management needs GOOD ANSWERS,
as quickly and cheaply as possible.
It’s a trade-off betweenSPEED and ACCURACY
In conclusion:
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