Transcript Document

Lecture 18, 03 Nov 2003
Chapter 9 (Aquatic Ecosystems)
Student Presentations
Conservation Biology
ECOL 406R/506R
University of Arizona
Fall 2003
Kevin Bonine
1. Aquatic Ecosystems (CH9)
2. Thank you cards
3. Syllabus Shuffle (Bob Steidl back one class)
Readings for Wed (SDCP):
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
Chapter 9 group presentations Monday:
8 minute highlights presentation, + 2 min QnA
(board, or overhead, or powerpoint [late Sunday])
Pages:
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
230-234
Tendick
Bobman
Fabry-Wood
Corral
234-238
Joslin
Vasquez
Barker
Misztal
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 Vulnerability
1.Recent disturbance
2.Predators absent
3.Effective Competitors absent
Invasion by Aquatic Plants
1.
2.
3.
4.
Introduction Usually by humans
Dispersal
occurs after survival and reproduction
Adaptation
via selection and establishment
Colonization
• Eurasian Water Milfoil
• Reproduces vegetatively
• Often transported by Human activity
• Reproduces Rapidly
•
• Distribution in the United States
• Other Aquatic Invaders
1. 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
Deegan
Gilliland
Friedrichs
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
Turbidity is balanced by:
• Nutrient inputs
• Fish populations
• Macrophyte & Periphytic algal populations
Thanks.
243-248
Backer
Carveth
Hartwell
Ramsey
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”
Total IBI Score Integrity Class of Site
Attributes
58-60
Excellent
Comparable to best situation
w/out human disturbance
48-52
Good
Species richness below
expected
40-44
Fair
Signs of deteriorationskewed
trophic structure
28-34
Poor
Growth rates and condition
factors depressed
12-22
Very Poor
Few fish present, most
introduced species
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.
2.
3.
4.
Globally outstanding
Continentally outstanding
Bioregionally outstanding
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
Sontz
Jarvie
Newsome
Nguyen
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.o
rg/Coral%20Forest/ma
p.html
Coral Reefs
• Structure-coral polyps
secrete calcium
• Nutrients-erosion of reefs
releases calcium
• Water quality-sponges
filter water
• Light-coral forms in welllit 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?
http://www.whoi.edu/institutes/doei/general/mission.htm • Metapopulations?
Whale Fall Communities
• Succession of
communities
• Decomposition of
bones yields hydrogen
sulfide
• DNA analyses of
fauna
• Implications for
http://www.nurp.noaa.gov/Spotlight%20Articles/whales.html
whaling?
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: Effects
•
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.
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
Behan
Dodds
Merin
END