biomonitoring and assessment why?. ecological society of america demand continues to increase but...

Biomonitoring and assessment

Why?

Ecological Society of America

Demand Continues to Increasebut we’re reaching a limit

Sadly -more why

“One child dies every 15 seconds from the lack of clean freshwater”

(> 2,000,000/year)

http://www.cwru.edu/artsci/engl/marling/60s/pages/richoux/Photographs.html

Along with Silent Spring etc.

Clean Water Act (1972)

Still an emphasis on chemistry

For many years following the passage of CWA in 1972, EPA, states, and Indian tribes focused mainly on the chemical aspects of the "integrity" goal. During the last decade, however, more attention has been given to physical and biological integrity. Also, in the early decades of the Act's implementation, efforts focused on regulating discharges from traditional "point source" facilities, such as municipal sewage plants and industrial facilities, with little attention paid to runoff from streets, construction sites, farms, and other "wet-weather" sources.

Starting in the late 1980s, efforts to address polluted runoff have increased significantly. For "nonpoint" runoff, voluntary programs, including cost-sharing with landowners are the key tool. For "wet weather point sources" like urban storm sewer systems and construction sites, a regulatory approach is being employed.

http://www.epa.gov/watertrain/cwa/

A Better BalanceBetween Chemistry, Biology, and Physical Habitat

Additionally, increasing emphasis on “nonpoint”

FEDERAL WATER POLLUTION CONTROL ACT(33 U.S.C. 1251 et seq.)

AN ACT To provide for water pollution control activities in the Public Health Serviceof the Federal Security Agency and in the Federal Works Agency, and for

other purposes.Be it enacted by the Senate and House of Representatives of the

United States of America in Congress assembled,TITLE I—RESEARCH AND RELATED PROGRAMS

DECLARATION OF GOALS AND POLICYSEC. 101. (a) The objective of this Act is to restore and maintainthe chemical, physical, and biological integrity of the Nation’s

waters. In order to achieve this objective it is hereby declared that,consistent with the provisions of this Act—

FEDERAL WATER POLLUTION CONTROL ACT[As Amended Through P.L. 107–303, November 27, 2002]

http://www.epa.gov/region5/water/pdf/ecwa.pdf

The Clean Water Act

Effects of Toxic Substances in Surface Waters

Most waste waters contain small amounts of chemical substances that with inadequate dilution or treatment may significantly impair survival potential of resident aquatic life. The capacity of rivers, lakes, and oceans to assimilate these wastes and toxic materials is not infinite, and serious water quality degradation is the inevitable result of the misuse and mismanagement of chemical resources. The 20th century witnessed substantial growth of the chemical industry. Millions of known chemical compounds exist, and an estimated 250,000 new compounds are synthesized each year. Of this number, it is estimated that approximately 1,000 new chemicals find their way into the environment annually as the end result of marketing, use, and disposal. The persistence and accumulation of hazardous substances such as pesticides and recalcitrant organics have resulted in the need for new and useful manufacturing containment and waste treatment procedures that will help protect aquatic life.

http://www.fisheries.org/resource/page6.htm

But why not just measure chemicals?

• Too many– >1000 in the environment each year– Analytical detection is very low – but often not low enough

• Too little testing– Relatively little effects-testing of primary chemical– Even less of degradation products– Practically none on resident biota– Too many possible synergistic effects to test

• Chemicals in lotic systems are often transient.

Ken Bencala USGS

Transient Presence

So, what is a pollutant?

The introduction into the environment by humans of a substance or energy (e.g., heat) that will interfere with the natural processes or

legitimate uses of that environment

Forms of Pollutants (Hynes)• Inert

– Sediments – e.g., from agriculture and forestry• Poisons

– Pesticides, acids, industrial wastes (metals), gender benders• Inorganic reducing agents

– Sulfides/sulfites – ↓ DO• Oil

– Toxicity, barrier to air breathers• Organic residues

– Sewage (human and animal) - ↓ DO, ↑ sedimentation• Water temperature

– Changes normal regime

But it’s just not pollutants it’s physical integrity as well

Deviation in natural flow regimes and

basin form and function

• Water capture and diversion• Agriculture• Forestry• (Sub)urbanization• Mining

Advantages of Biological Measures

• Integration– Temporal

• But …– Stressor type

• But …

• Often the measure in which society is most interested– How many fish!

Advantages of Evaluating Aquatic Invertebrates

• Ubiquitous• Extremely species rich• Sedentary (mostly)• Long life cycles (relatively)• Most often used

– All states, multiple federal programs in many nations• Extremely long history

– Kolkwitz and Marsson (Saprobity)• Cute

But – ongoing research is needed

• Integration?• Other habitats (particularly large rivers)• Cause and effect often speculative• More basic biology/ecology is necessary• Poor knowledge of natural distributions• Better taxonomy (particularly e.i.)

• … should keep us in work for a long time!

Scales of Monitoring(Biological levels)

• Biochemical/physiological• Individual• Population• Community (assemblage)• Ecosystem

Each level generally has an associated temporal scale associated with it

Biochemical/Physiological

• Enzyme activity• Respiration• Metal partitioning

– MBPs

• Crucial to our understanding of mode of action

Individual/Organism• Deformities

– Chironomidae– Gender-benders in

fishes• Behavior

– Avoidance• Life-history

– Hatching success• Sentinel organisms

– Body burdens

Warwick: midge deformities

Populations and assemblages

• More often used– Biotic indices

• The link that is often missing– High variance

• At least how we currently measure it/them

Community

Ecosystem

• Not often done– Expensive– Difficult to replicate

• But ELA

• Where we would like to be because– Evaluating processess

not just structure and function

Hubbard Brook: Likens et al.

Experimental Lakes Area: Schindler et al.

Mesocosms: principally lakesbut:SNARL

Other methods

• Toxicity testing– Acute and chronic– Single species and multiple species– Laboratory and field (Clements)

• Paleolimnological Methods– Midge (and others) head capsules

• Sediment dating• bioturbation

Community

Better term – assemblageWhy? – but we’ll use

Community

But also -Why the “community” level?

• In most cases, save T&Es, there isn’t a single species with which we’re concerned– None identified as “diagnostic” of any given stressor

and• We’re not talking salmon here

– High (possibly unmanageable variance)• Rethink (i.e., test) different approaches

– Evan Hornig

• Ubiquitous – yes, but we expect species turnover in space and time

• Used more often than any other level of biological organization

Are these two approaches different?

• Quantitative– Most studies in the US

before 1989 (and some after)?

– Collection “quantitative”– Relative small spatial scale– Replication

• But was it proper?– High resolution taxonomy

• Qualitative– Most studies post RBP– Collection “qualitative”– Much larger spatial scale– Considered un-replicated

• But probably replicated at the right spatial scale

– Taxonomy likely less resolved

• But …not always

What’s the question?

What’s the point?

• Describe a site (= sample unit) based on the species (or types) present and the distribution of individuals among these species.

• Compare and contrast between/among sites.

Types of measures

• Richness• “Enumerations”• Diversity• Similarity• Biotic indices• “Functional” (e.g., FFGs)• Combination = multimetrics• Multivariate

Richness (=S)• The most frequently used “single” measure

– Often determined for a subset of the assemblage• EPT

– Considered less tolerant of “pollution”• And – at taxonomic levels other than species

• Assumption is that S ↓ with ↑ impairment – but …– Variable in space and time

• Think of all the reasons we discussed– Extremely method sensitive

• Field – not well tested• Lab – some testing

• Rarefied– We now know this but …

• No standard method– Lab and/or computer

• What is it’s meaning (Courtemanch)– An index of richness/evenness

Inflated richness as a function of sorted N

“Enumerations”• “Simplest” measure

– Total number of individuals – but …• 0 – 100,000 m-2 (mean = 4000)

– Therefore subsampling is necessary– ↑ error

– Total number of individuals within a group• Taxonomic, FFG, etc.

• Often standardized to 100 = percentage composition– % within a group

• Taxonomic (e.g., % EPT)• FFG (e.g., % shredders• Ratios (% EPT/ (% Chironomidae +% EPT)) but …

• Expected response is a function of the hypothesized response of the group to the stressor– High temporal variability– Meaning ???

Diversity• Was the summary measure of the ’60s and ’70s

– Hurlbert (1971) rightfully questioned it’s value• Still a part of many “multimetrics”• Many, many different formulae

– Shannon, Simpson, etc.– “Integrates” richness and evenness because 2 sites may have similar

richness but extremely different distributions of individuals among the species …e.g.,

• Species A B C D E• 90 5 3 1 1• 40 30 20 6 4

• Assumption is that diversity ↓ as impairment ↑ but …– Many factors influence the “diversity” of a site (= alpha diversity), such as

…• The species available in the region (gamma diversity)• Productivity, habitat diversity, and all the factors we talked about that influence S

n

iii ppH

1

log

As an example: Shannon

where,

pi = the percentage of the ith species and there are n total species.

Note that the identify of the species is not required – only the differentiation of one species from another.

Diversity is often viewed in light of evenness (J)

max/ HHJ ,where SH logmax

Highly correlated with S

Similarity Measures(my personal favorites)

• Can be based on:– Presence/absence data– Percentage composition– Abundance

• Objective:– As defined, evaluate the similarity between (more so than

among) unimpaired vs. impaired sites.• Assumption

– ↑ impairment ↓ similarity – but …• Nasty to work with• Difficult to summarize• Often are non-linear with increasing difference• But … again – seem more like what we “see” when we look at two

pans of bugs!

cbaa

bcbcJC

where,a = the number of species in common,b = the number of species only in sample bc = the number of species only in sample c

s

iikij

s

iikij

jk

xx

xxPS

1

1

),max(1

PSjk = percentage similarity between sample j and sample kxij = the abundance of species i in sample jxik = the abundance of species i in sample ks = the total number of species in samples j and k

Present in B and C

Only present in B

Present in C and B a bOnly present in C

c d

Jaccard Coefficient andPercentage Similarity

Biotic Indices• Numerous have been developed

– Saprobien Index (Kolkwitz and Marsson 1909)• Valences

– In the US, the most often used measures are those developed by Hilsenhoff

• Family Biotic Index• Modified for season, taxonomic level, etc.

• Methods are dependent on the assignment of (in)tolerance values• Assumptions

– ↑ impairment (normally organic) ↓ or ↑ biotic index depending on how it is scaled

– Tolerance values are rarely empirically derived• Often the derivation and application are circular• Tolerances principally represent response to organic pollution

– Sensitive to taxonomic level

Weighted-average

n

ii

n

iii abundancetoleranceabundance

Measures of “function”• Functional feeding group

– Should be based on method of food acquisition• But often based on gut analysis

– Problem with what is or is not assimilated• Distinction between

– FFG• Scrapers, shredders, collector -gatherers and –filterers, predator … vs:

– Trophic level• Detritivore, herbivore, omnivore, carnivore

• Mobility or lack thereof– Clingers, sprawlers, swimmers, …

• Assumption– Response is some function of the disturbance– Most often based on % composition therefore sensitive to all those

factors that can influence % composition temporally and spatially

Combinations (= multimetrics)• First developed by Jim Karr for fish

– Index of Biotic Integrity• Based on the concept of economic indices

– Regardless, the idea is that no single measure will indicate the status of a site therefore, it’s necessary to combine a number of different measures (=metrics)

– Metrics are chosen that represent a range of response types (e.g., richness, % composition, diversity, ffg, biotic indices)

• They also are chosen to maximize differences between reference and impaired.

– These individual measures are scaled and combined additively (most often) and then often rescaled to range from 1 to 10

• Identifying impairment is based on a sites “value” relative to the established range

• Well …– If one measure is intractable – maybe adding up a bunch will make

sense???– It’s really not that bad – sorry.

Go back to similarity slide

Multivariate Methods

Oh my!

Multivariate Methods

• Using all the data simultaneously– Often both species and environmental

Multivariate• Direct gradient analysis

– Variation is species distributions are are determined• Often then related to environmental variables

• Inference– Species distributions are used to infer environmental variables

• Temperature in Montana

• Indirect gradient analysis– Searches for gradients in species data which are interpreted in

terms of environmental data• Constrained ordination

– Axes of variation in species data is constrained within the variation in environmental data.