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31 January 20058th class meeting

(Miller Chapters 3 and 4)

Environmental BiologyECOL 206

University of Arizonaspring 2005

Kevin Bonine, Ph.D.Alona Bachi, Matthew Herron, Graduate TAs

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206 Course Web Link:http://eebweb.arizona.edu/courses/Ecol206/206_Page2005.html

• Lab outside this week, bring binoculars?• Check out lab course website.

• Groups form this week for Projects• Dillard reading for Wed.• Value of Ecosystems reading for Friday.• Miller Chapters 4 and 3

(check out the CD/websitefor Miller text)

Lecture Tues 7pm, DuVal Auditorium AHSC/UMC“Feeding 9 billion people in next 50 yrs”

Environmental Biology 2062

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2005

Guy McPherson

Appearance:Arizona Illustrated 6:30pmand Midnight 02 Feb, Wed

Book Signings:Greenfire Bookstore1-3pm Sat 05 Feb

Reader’s Oasis1pm Sun 06 Feb

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Biological InvasionsKathy Gerst

Dept. of Ecology and Evolutionary Biology

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Invasives:Buffel grassBullfrogBrown Tree SnakeTamariskCane Toad

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The Brown Tree Snake (Boiga irregularis) was accidentally introduced to Guam in the late 1940’s or early 1950’s on U.S. military cargo. The native range of the snake is Northeastern Australia, New Guinea and some of the islands around New Guinea. It is thought that the Guam snakes originated from the island of Manus, a small island in the Solomons.

By the late 1950’s/early 1960’s it was well known that Guam had a snake population, often referred to as the "Philippine Rat Snake". What was not known was the devastating effect this introduced snake was having on Guam’s native species, especially birds.

Not having evolved with a nighttime arboreal (tree climbing) predator, the native birds had no behavioral or physical defenses. As a result, birds began disappearing with the smaller species being affected first. By the mid 1980’s, 9 of 11 native forest birds were gone from Guam’s forests. Two of these birds, the Micronesian Kingfisher and the Guam Rail, were found only on Guam (endemic) and to this day only exist in zoos. Guam’s forests had become silent.

Due to the loss of bird life, insect populations are much higher on Guam (many birds eat insects). Because many birds pollinate plants and spread seeds, Guam will probably exhibit vegetation changes in the forests. Guam is rightly termed one of the modern day eco-disasters.

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Electrical Outages: Approximately every third day there is a snake-caused power outage somewhere on Guam. While most of these affect a limited area, some are widespread or island-wide blackouts. Everything from school lighting, computers used by retail outlets, traffic signals, to refrigeration of perishable goods are subject to these power interruptions. The costs due to direct damages and lost productivity are conservatively estimated at $1-4 million dollars each year.

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Rodda, Fritz, Chiszar 1997...

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GuamBoiga irregularisBrown Tree Snake

-power outages, gnawed on babies-wiping out native vertebrates

-Lack of shared evolutionary history-Ecologically naïve native fauna-Human commerce etc.

Other islands? Other species?

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Niche vs. Habitat9

Generalist vs.Specialist

Narrow niches: 1. red-cockaded woodpeckers2. giant pandas

Occupation vs. address

-Tolerance to physical and chemical conditions-Types and amounts of resources used-Interactions with biotic and and abiotic environment-Role in energy and matter cycling

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Niche

Miller 2003

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11Cockroaches, Amazing Generalists

Ricklefs 2001

Ricklefs 2001

Human Population Growth

Exponential Growth

LogisticGrowth

Ricklefs 2001

VanDyke 2003 12

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On p.176 in VanDyke 2003 (Ch7) is the following quote:

“the exponential growth curve ‘has no ecology.’”

What does this quote mean?

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Population Growth:

Miller 2003

1. Exponential growthdensity-independent

In a closed population (no immigration or emigration),population growth is a function of birth and death rates

dNdt

= (b-d)N

Ring-necked pheasanton Protection Island

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dNdt

= rN K-NK( ) intraspecific competition

stabilizes population sizebirth rates go down and/or death rates go up with increasing population size

2. Logistic growth density-dependent

carryingcapacity (K)

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a

b

r = intrinsic rate of increase

1. Limited by - resources- competition- predators

K = carrying capacity

Rate that population could grow with unlimited resources

“r-selected” organisms:1. Reproduce early and often2. Short generation times3. Many offspring

Therefore have intraspecific competition.

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Miller 2003

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r-selected Rabbits in Victoria, Australia

1859 -- European Rabbits (12 pairs)introduced on ranch

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1900 – Hundreds of millions of rabbitsRangeland destruction

1950 – Myxoma virus introduced99.8% mortality

recovery then 80% mortalityrecovery then 50% mortality

recoveryresistant

millions and millions of rabbits

http://rubens.anu.edu.au/student.projects/rabbits/home.html

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Native Speciesvs.

Nonnative, exotic, alien

Indicator Species-migratory birds-amphibians

Rana pipiensNorthern Leopard Frog

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Keystone Species-top predators-key pollinators

Aquatic and Marine Environments

A. Salinity

B. Layers:1. Temperature2. Sunlight3. Dissolved O24. Nutrients

- carbon- nitrogen (nitrate)- phosporus (phosphate)

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Marine Environments

71% earth’s surface is ocean

coastal vs. open sea

10% area, 90% specieshigh NPP

- nutrients- sunlight

1. Estuaries2. Coastal Wetlands

- mangroves- salt marshes

3. Coral Reefs

- Role of sunlight- Not very productive per unit area- Lots total NPP

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Miller, 2003

Marine Environments

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Aquatic Environments

Only 1% earth’s surface:

1. Lakes

2. Streams

3. Rivers

4. Inland Wetlands

nutrients, clarity, NPP- oligotrophic- eutrophic

- Watershed- Runoff- Erosion

Marshes, swamps, floodplains

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Fig 3-18, Miller, 2003

Aquatic Environments

- oligotrophic

- eutrophic

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Miller 2005

Freshwater Ecosystem Services

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