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.PDF

Listed 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 in Freshwater Habitats

• Eutrophication• Acidification• Habitat Alteration

– Invasive plant species

– Invasive invertebrates

– Invasive vertebrates

Conservation Challenges 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 and phosphorus, which encourage the growth of aquatic organisms

• The lake's fertility increases, and organic remains begin to be deposited on the lake bottom

Eutrophication

• Silt and organic debris increase on lake bottom, lake becomes shallower and warmer, less oxygen

• Warm-water organisms supplant those that thrive in a cold environment

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

• Depending on climate, size of the lake, and other factors, the natural aging of a lake may span thousands of years

Eutrophication

• Pollutants from man's activities can radically accelerate the natural aging process

• Lakes have been severely eutrophied by sewage, agricultural and industrial 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 Congress in the National Water Quality Inventory– Approximately 40% of the nation's surveyed

lakes, rivers, and estuaries were too polluted for such basic uses as drinking supply, fishing, and swimming

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

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, plastic wrappers, and adhesives

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

Acidification

• Hydrogen sulfide, NOx and SO2 from coal burning for electricity

• Nitrous oxide from car exhaust

• Combine with water to form sulfuric and nitric 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 Nonindigenous Species

Aquatic Enviroments Vulnerability1.Recent disturbance2.Predators absent3.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 water

2. 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 conservation strategies may have to be fundamentally altered to preserve biodiversity.”

Van Dyke 2003 (pg 238)

239-243

DeeganGillilandFriedrichs

Conserving Aquatic Habitats

Managing Sedimentation & Eutrophication

Why?

Mmm ...

… yummy!

The Culprits

• Us! (surprise)

Primary Cause: Erosion

• modern agricultural runoff

• urban sewage & waste disposal

• land development -- “impermeability”

Sociopolitical causes need sociopolitical 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 out phosphorus.

• Additional reactions raise O2 levels, stabilize pH, & encourage denitrifying bacteria in the sediment to release excess nitrate 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 Management for Freshwater Environments

Sarah, Jenna, Cori and Dana

Monday November 3, 2003

The Wild and Scenic Rivers Act

• Most significant legislation protecting streams and rivers

• Introduced in 1968

Verde 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 federal agency that would adversely affect its water quality

Problems…

• 1990- Less than 2% of U.S. streams were deemed sufficient to merit protection under this act

• This means that less than 100,000km out of 5.2 million km’s are protected

San Pedro River, Arizona

Water Pollution Control Act, 1972

• Amendment to the Clean Water Act

Directed EPA to “restore and maintain the physical, chemical and biological integrity of the nation’s waters” and to enhance all forms

of aquatic life

• A more biologically oriented approach to protecting the nations waters

Problems…

• Only chemical standards enforced– Does not ensure that

entire ecosystem is functional

– Many impacts that degrade aquatic systems are not detected by chemical monitoring

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, most introduced species

Very Poor12-22

Growth rates and condition factors depressed

Poor28-34

Signs of deteriorationskewed trophic structure

Fair40-44

Species richness below expected

Good48-52

Comparable to best situation w/out human disturbance

Excellent58-60

AttributesIntegrity Class of SiteTotal IBI Score

Advantages…

• Focuses on distinct attributes of the system

• Inexpensive

• Simple and sensitive to ecological change

• Incorporates professional ecological opinion

International and National Legislation for Wetlands

• Wetlands were one of the first cases in which international legislation focused on the protection of an ecosystem instead of a species.

• The Ramsar Convention, was the first global conservation convention to focus on the wetlands ecosystem. The convention obligates its signers to identify and designate at least one wetland in their country as a “wetland of international importance” and to establish wetland nature reserves.

Canada’s federal policy on wetland conservation is one of the best national examples of implementing the ideals of

Ramsar and has experienced remarkable success.

The Canadian policy articulates strategies for 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 all federal programs

• Secures and protects wetlands of national importance.• Uses wetlands in a sustainable manner.• Allows no net loss of wetlands on federal lands and

waters.

The U.S. has designed a number of legislation acts to address

wetland conservation in an act to increase preservation and restoration of these areas.

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

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

Agriculture benefits to farmers who drain wetlands on their land.

• Creates an eligibility requirement for farmers to receive Administration loans and other benefits.

Wetland Reserve Program (WRP)

• Provides for payment of subsidies to farmers who remove croplands from production in former wetland areas and to reestablish the land as wetlands

• To enroll in WRP, the landowner’s plan must include drainage alterations and the establishment of marsh plants on the enrolled site.

Other examples of U.S. programs or acts implemented 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 wetland loss).

• Some U.S. legislation still encourages the draining of wetlands. For example the U.S. tax code encourages farmers to drain and clear wetlands by providing tax deductions for many types of development activities.

Setting Priorities for Conservation in Freshwater

Habitats

• WWF-US criteria for assessment of lakes and streams

1. Biological distinctiveness

2. Conservation status

• Gives priority to regions that contain systems that contribute to biodiversity

1. Globally outstanding

2. Continentally outstanding

3. Bioregionally outstanding

4. Nationally important

• Priority declines as the importance of the system decreases

Rankings...

I Critical (intact habitat reduced to small, isolated patches; small probability of persistence over the next 10 years without immediate action)

II Endangered (intact habitat of isolated patches with low to medium probability of persistence over the next 10 years without immediate or continuing protection)

III Vulnerable (intact habitat remaining in large and small areas, persistence is likely over the next 10 years with protection and restoration)

IV Relatively Stable (disturbance and alteration in certain areas, but overall stable; external practices unlikely to impact habitat)

V Relatively Intact (minimally disturbed)

Rule-Based Models

• Used to determine if habitat loss or environmental change are random

• Evaluate possible mechanisms of distributional changes in a species

Disappearance of Frogs

• Isolation model: due to distances between changes in distribution ponds

• Succession model: changes in distribution due to altered vegetation in and around ponds

• Null model: changes

in distribution were

random

• Results of the study showed that the Succession Model was correct

• Frogs could best be preserved by managing the vegetation

• Rule-based models require minimal data, don’t necessarily need to prove that changes in vegetation cause frog declines, only that managing vegetation may help frogs more than 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 polyps secrete calcium

• Nutrients-erosion of reefs releases calcium

• Water quality-sponges filter water

• Light-coral forms in well-lit waters, favorable for photosynthesis

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

Benthos

• Ocean bottom, excluding the deepest areas

• Sand, silt and decomposing organic matter

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

Seagrass Beds

• 15% decline in past decade

• 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

• Chemosynthetic bacteria

• Huge taxonomic diversity

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

Whale Fall Communities

• Succession of communities

• Decomposition of bones yields hydrogen sulfide

• DNA analyses of fauna

• Implications for whaling? 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 Commercial Species

• 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

1. Exploitation of Commercial Species

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

depleted– 45% of all species are over-harvested

1. Exploitation of Commercial Species

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

abundance.– Do not necessarily show a strong correlation

between recruitment and number of adults present.

– Do not necessarily show advanced warning of population decline.

1. Exploitation of Commercial Species: EffectsEffects

• Removal of a prey species may reduce the populations of predators.

Ex. Decline of sea otters in CA following over-fishing of abalones.

2. Removal of predator species disrupts equilibria of prey species.

1. Exploitation of Commercial Species: Effects cont.Effects cont.

3. The take of non targeted species contributes to exploitation problems.

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

2. Direct destruction of Marine Habitats

• 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

END