chapter 9 (aquatic ecosystems) student...

Lecture 18, 03 Nov 2003Chapter 9 (Aquatic Ecosystems)

Student Presentations

Conservation BiologyECOL 406R/506R

University of ArizonaFall 2003

Kevin Bonine

1 Aquatic Ecosystems (CH9)2. Thank you cards3. Syllabus Shuffle (Bob Steidl back one class)

Overview of Reserve Design http://www.co.pima.az.us/cmo/sdcp/reports/d20/096OVE.PDFListed Species Reserve http://www.co.pima.az.us/cmo/sdcp/reports/d10/021LIS.PDF

Readings for Wed (SDCP):

Chapter 9 group presentations Monday:8 minute highlights presentation, + 2 min QnA(board, or overhead, or powerpoint [late Sunday])

230-234 Amy Tendick, Galia Bobman, Aurora Fabry-Wood, Leonides Corral

234-238 Ben Joslin, Andrea Vasquez, Bridget Barker, Louise Misztal

239-243 Christopher Deegan, Michael Gilliland, JD Friedrichs

243-248 Dana Backer, Cori Carveth, Sarah Hartwell, Jenna Ramsey

248-255 Erica Sontz, Meghan Jarvie, Ginny Newsome, Linh Nguyen

255-264 Maeveen Behan, Justin Dodds, Lauren Merin

Pages:

230-234

TendickBobmanFabry-WoodCorral

234-238

JoslinVasquezBarkerMisztal

Conservation Challenges inFreshwater Habitats

• Eutrophication• Acidification• Habitat Alteration

– Invasive plant species– Invasive invertebrates– Invasive vertebrates

ConservationChallenges of

Freshwater Habitat

The Issues

• Eutrophication• Acidification• Habitat Alteration by NIS’s

– Plant– Animal

Eutrophication

• Natural process of the aging of a lake• In a young lake, the water is cold and

clear, and supports little life• Streams drain into the lake, introducing

nutrients such as nitrogen andphosphorus, which encourage thegrowth of aquatic organisms

• The lake's fertility increases, andorganic remains begin to be depositedon the lake bottom

Eutrophication• Silt and organic debris increase on lake

bottom, lake becomes shallower and warmer,less oxygen

• Warm-water organisms supplant those thatthrive in a cold environment

• Marsh plants take root in the shallows andbegin to fill in the original lake basin and thelake gives way to a bog, and finally into land

• Depending on climate, size of the lake, andother factors, the natural aging of a lake mayspan thousands of years

Eutrophication

• Pollutants fromman's activitiescan radicallyaccelerate thenatural agingprocess

• Lakes have beenseverelyeutrophied bysewage,agricultural andindustrial wastes

Eutrophication• Primarily from increased nitrates and

phosphates, which act as plant nutrients• Stimulate the growth of algae• Cause unsightly scum and unpleasant odors• Reduction of dissolved oxygen, which is vital

to other aquatic life• Other pollutants flowing into a lake may

poison whole populations of fish• Decomposing remains further deplete the

water's dissolved oxygen content

Pollutants

• In 1996, the EPA reported to Congressin the National Water Quality Inventory– Approximately 40% of the nation's

surveyed lakes, rivers, and estuaries weretoo polluted for such basic uses as drinkingsupply, fishing, and swimming

– The pollutants include grit, asbestos,phosphates and nitrates, mercury, lead,caustic soda and other sodium compounds,sulfur and sulfuric acid, oils, andpetrochemicals

Pollutants• Manufacturing plants pour off undiluted corrosives,

poisons, and noxious byproducts• The construction industry discharges slurries of gypsum,

cement, abrasives, metals, and poisonous solvents• A pervasive group of contaminants is polychlorinated

biphenyl (PCB): components of lubricants, plasticwrappers, and adhesives

• Hot water discharged by factories and power plants causesthermal pollution, lower oxygen

Acidification

• Hydrogen sulfide,NOx and SO2 fromcoal burning forelectricity

• Nitrous oxide from carexhaust

• Combine with water toform sulfuric andnitric acid

Acidification• Rain is slightly acidic• Buffering by carbonates, some freshwater systems are

more susceptible to acidification• High acidity affects reproduction of fish, amphibians and

invertebrates• Direct mortality• Change in chemical reactions, metallic ions may

precipitate out of solution• Acidification can happen rapidly: pH from 7 to 4 in 24

hour period in Scotland during heavy rain, massive fish kill

Habitat Alteration By NonindigenousSpecies

Aquatic Enviroments Vulnerability•Recent disturbance•Predators absent•Effective Competitors absentInvasion by Aquatic Plants 1. Introduction Usually by humans 2. Dispersal occurs after survival and reproduction 3. Adaptation via selection and establishment 4. Colonization

• Eurasian Water Milfoil• Reproduces vegetatively• Often transported by Human activity• Reproduces Rapidly•

• Distribution in the United States

• Other Aquatic Invaders1. Purple Loosestrife

– Chokes out natural vegetation in shallow water2. Water hyacinth

– forms dense mats in deep water

Animal NIS’s in Freshwater

• Properties:– High reproductive rates– Wide environmental tolerances– Large dispersal distances

3 Examples:

The Zebra Mussel

The Spread of…

The Carp (Cyrinus carpio)

The Nile Perch (Lates niloticus)

The demise of the Haplochromis spp.of cichlid fish

• Take Home Lesson?–“Managers must consider that if (there

are chemical alterations to a system or a)nonindigenous (species) enters a system,habitat management and conservationstrategies may have to be fundamentallyaltered to preserve biodiversity.”

Van Dyke 2003 (pg 238)

239-243

DeeganGillilandFriedrichs

Conserving Aquatic Habitats

Managing Sedimentation &Eutrophication

Mmm ...

… yummy!

The Culprits

• Us! (surprise)

Primary Cause: Erosion

• modern agricultural runoff• urban sewage & waste disposal• land development -- “impermeability”

Sociopolitical causes needsociopolitical remedies:

• We must enact laws & policies to:• Reduce chemical fertilizer use• Remove compounds from urban discharge• Reduce agricultural & landscaping erosion

Urban Abatement no.1

Urban Abatement no.2

Restoration

• Dredging• Chemistry• Biomanipulation

Dredging

• Remove & Purify Contaminated Sediments

Chemistry -- Riplox method

• Oxidize sediment surface to precipitate outphosphorus.

• Additional reactions raise O2 levels,stabilize pH, & encourage denitrifyingbacteria in the sediment to release excessnitrate as gas into the atmosphere.

Bioremediation

Bioremediation continued

Alternative Stable States

• Nutrient inputs• Fish populations• Macrophyte & Periphytic algal populations

Turbidity is balanced by:Turbidity is balanced by:

Thanks.

243-248

BackerCarvethHartwellRamsey

Legislation and Managementfor Freshwater Environments

Sarah, Jenna, Cori and DanaMonday November 3, 2003

The Wild and Scenic Rivers Act

• Most significantlegislationprotecting streamsand rivers

• Introduced in 1968Verde River, Arizona

What is it??• Under this act, a stream or section of a

stream is designated as wild and scenic

• Protected from any action by any federalagency that would adversely affect its waterquality

Problems…

• 1990- Less than 2% of U.S. streams weredeemed sufficient to merit protection underthis act

• This means that lessthan 100,000km outof 5.2 million km’sare protected

San Pedro River, Arizona

Water Pollution Control Act,1972

• Amendment to the Clean Water Act

Directed EPA to “restore and maintain thephysical, chemical and biological integrity ofthe nation’s waters” and to enhance all forms

of aquatic life

• A more biologically oriented approach toprotecting the nations waters

Problems…

• Only chemicalstandards enforced– Does not ensure that

entire ecosystem isfunctional

– Many impacts thatdegrade aquaticsystems are notdetected by chemicalmonitoring

Cienega Creek, Arizona

Indices of Biotic Integrity (IBI)• Ecologically based measurements of water quality• A particular taxon (i.e. fish) is rated and scored

based on 3 different attribute groups– Species Richness and Composition

• i.e.Number and identity of benthic species

– Trophic Composition• i.e. Percentage of omnivores

– Fish abundance and Condition• i.e. Number of individuals with disease, fin damage and

skeletal anomalies

IBI’s Continued..• Site scored and assigned an “integrity class ranking”

Few fish present, mostintroduced species

Very Poor12-22

Growth rates and conditionfactors depressed

Poor28-34

Signs of deteriorationskewedtrophic structure

Fair40-44

Species richness belowexpected

Good48-52

Comparable to best situationw/out human disturbance

Excellent58-60

AttributesIntegrity Class of SiteTotal IBI Score

Advantages…• Focuses on distinct attributes of the system

• Inexpensive

• Simple andsensitive toecological change

• Incorporatesprofessionalecological opinion

International and NationalLegislation for Wetlands

• Wetlands were one of the first cases in whichinternational legislation focused on the protectionof an ecosystem instead of a species.

• The Ramsar Convention, was the first globalconservation convention to focus on the wetlandsecosystem. The convention obligates its signers toidentify and designate at least one wetland in theircountry as a “wetland of international importance”and to establish wetland nature reserves.

Canada’s federal policy onwetland conservation is one ofthe best national examples ofimplementing the ideals of

Ramsar and has experiencedremarkable success.

The Canadian policy articulates strategiesfor sustainable use and management of the

nation’s wetlands.• Provides for the maintenance of overall wetland

function.• Enhances and rehabilitates degraded wetlands.• Recognizes wetland functions in planning,

management, and economic decision making in allfederal programs

• Secures and protects wetlands of nationalimportance.

• Uses wetlands in a sustainable manner.• Allows no net loss of wetlands on federal lands

and waters.

The U.S. has designed a numberof legislation acts to address

wetland conservation in an act toincrease preservation andrestoration of these areas.

The 1985 Food Security Act, aka“Swampbuster” is designed to stop theprocess of draining wetlands in private

agricultural lands.• Denies most U.S. Department of

Agriculture benefits to farmers who drainwetlands on their land.

• Creates an eligibility requirement forfarmers to receive Administration loans andother benefits.

Wetland Reserve Program (WRP)

• Provides for payment of subsidies tofarmers who remove croplands fromproduction in former wetland areas and toreestablish the land as wetlands

• To enroll in WRP, the landowner’s planmust include drainage alterations and theestablishment of marsh plants on theenrolled site.

Other examples of U.S. programs or actsimplemented to protect and preserve

wetlands.• Clean Water Act• Migratory Bird Hunting and Conservation Stamps• Federal Aid to Wildlife Restoration Act• Wetlands Loan Act• Land and Water Conservation Fund• Water Bond Program• Executive Order 11988 Floodplain Management• Executive Order 11990 Protection of Wetlands• Coastal Zone Management Act• Payment-in-kind program

Despite conservation efforts,wetlands loss in the U.S. still

continues in part because:• There is a lack of agency coordination in wetland

conservation.• Most legislation does not regulate private activity

on private lands (cause of majority of wetlandloss).

• Some U.S. legislation still encourages the drainingof wetlands. For example the U.S. tax codeencourages farmers to drain and clear wetlands byproviding tax deductions for many types ofdevelopment activities.

Setting Priorities forConservation in Freshwater

Habitats

• WWF-US criteria for assessment of lakesand streams1. Biological distinctiveness2. Conservation status

• Gives priority to regions that containsystems that contribute to biodiversity

1. Globally outstanding2. Continentally outstanding3. Bioregionally outstanding

4. Nationally important

• Priority declines as the importance of thesystem decreases

Rankings...

I Critical (intact habitat reduced to small,isolated patches; small probability ofpersistence over the next 10 years withoutimmediate action)

II Endangered (intact habitat of isolatedpatches with low to medium probability ofpersistence over the next 10 years withoutimmediate or continuing protection)

III Vulnerable (intact habitat remaining inlarge and small areas, persistence is likelyover the next 10 years with protection andrestoration)

IV Relatively Stable (disturbance andalteration in certain areas, but overall stable;external practices unlikely to impacthabitat)

V Relatively Intact (minimally disturbed)

Rule-Based Models

• Used to determine ifhabitat loss orenvironmental changeare random

• Evaluate possiblemechanisms ofdistributional changesin a species

Disappearance of Frogs

• Isolation model: due to distances betweenchanges in distribution ponds

• Succession model: changes in distributiondue to altered vegetation in and aroundponds

• Null model: changes in distribution were random

• Results of the study showed that theSuccession Model was correct

• Frogs could best be preserved by managingthe vegetation

• Rule-based models require minimal data,don’t necessarily need to prove that changesin vegetation cause frog declines, only thatmanaging vegetation may help frogs morethan another type of plan

248-255

SontzJarvieNewsomeNguyen

Marine Habitats and Biodiversity

http://www.ucmp.berkeley.edu/vertebrates/coelacanth/coelacanths.html

Marine Habitats

• Intertidal• Pelagic• Benthic• Abyssal

•Coral Reefs•Estuaries•Seagrass Beds (benthic)

http://www.onr.navy.mil/focus/ocean/regions/bluewater1.htm

Coral Reefs• Shallow, tropical water• 20o N and S of equator• Indo-Pacific, Western Atlantic, Red Sea

http://www.reefrelief.org/Coral%20Forest/map.html

Coral Reefs

• Structure-coral polypssecrete calcium

• Nutrients-erosion of reefsreleases calcium

• Water quality-spongesfilter water

• Light-coral forms in well-lit waters, favorable forphotosynthesis

http://www.photolib.noaa.gov/reef/reef2584.htm

Benthos

• Ocean bottom,excluding the deepestareas

• Sand, silt anddecomposing organicmatter

• Often dark• Often cold• Nutrient rich http://www.photolib.noaa.gov/nurp/nur00512.htm

Seagrass Beds

• 15% decline in pastdecade

• Flowering plants• Food resource, nursery,

habitat• Prevent erosion• Reduce wave impact• Filter water

http://www.photolib.noaa.gov/sanctuary/sanc0211.htm

Hydrothermal Vents

• Mid-ocean ridges,tectonic plates

• Chemosyntheticbacteria

• Huge taxonomicdiversity

• Old?• Relict species?• Metapopulations?http://www.whoi.edu/institutes/doei/general/mission.htm

Whale Fall Communities

• Succession ofcommunities

• Decomposition ofbones yields hydrogensulfide

• DNA analyses offauna

• Implications forwhaling? http://www.nurp.noaa.gov/Spotlight%20Articles/whales.html

Major threats to Marine Habitats:

• 1. Exploitation of commercial species• 2. Direct destruction of marine habitats• 3. Indirect degradation of marine habitats

1. Exploitation of CommercialSpecies

• Maximum Sustainable Yield (MSY):– Used to manage fisheries as renewable

resources– Calculated based on catch per unit effort– Reproductive surplus was the only requirement

for a sustainable fishery– Not used in fisheries anymore because it caused

depletion in fish stocks


• Current Estimates:– 70% of the world’s fish stocks are exploited or

depleted– 45% of all species are over-harvested


• Over-harvested Populations:– Show widely ranging cycles of high and low

abundance.– Do not necessarily show a strong correlation

between recruitment and number of adultspresent.

– Do not necessarily show advanced warning ofpopulation decline.

1. Exploitation of CommercialSpecies: EffectsEffects

• Removal of a prey species may reduce thepopulations of predators.Ex. Decline of sea otters in CA followingover-fishing of abalones.

2. Removal of predator species disruptsequilibria of prey species.

1. Exploitation of CommercialSpecies: Effects cont.Effects cont.

3. The take of non targeted species contributesto exploitation problems.

Ex. In shrimp fisheries, the discarded by-catch can exceed that of the targeted catch.

2. Direct destruction of MarineHabitats

• Examples of Direct Destruction:– The use of explosives to harvest coral reef

species. One blast can devastate 1000m3.– Trawling nets destroy complex and diverse

communities on the ocean floor. (figure 9.15)

255-264

BehanDoddsMerin

chapter 9 (aquatic ecosystems) student...

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