Community Interactions

Community Interactions

Forest of New Guinea  Community

includes nine species of

pigeons that partition the food supply  Pigeons

disperse seeds of the trees

that provide their food (fruit)  These

are just a few of the many

interactions that shape this community

New Guinea Crowned Pigeon

www.worldwildlife.org/newguinea/spec_pigeons.cf

Map of New Guinea  New

Guinea is an Island north of Australia www.worldwildlife.org

Community   All the populations that live together in a 

habitat  Habitat is the type of place where 

individuals of a species typically live   Type of habitat shapes a community’s 

structure

Communities  Don’t

confuse meanings of “community”

Factors Shaping Community Structure  Climate

and topography

 Available

foods and resources

 Adaptations  Species  Arrival

of species in community

interactions

and disappearance of species

 Physical

disturbances

Niche Sum of activities and relationships in which a species engages to secure and use resources necessary for survival and reproduction

Realized & Fundamental Niches  Fundamental

niche

– Theoretical niche occupied in the absence of any competing species  Realized

niche

– Niche a species actually occupies  Realized

niche is some fraction of the fundamental niche

Species Interactions  Most

interactions are neutral; have

no effect on either species  Commensalism

helps one species

and has no effect on the other  Mutualism

helps both species

Commensalism The commensal shrimp Periclimenes imperator on Chromodoris tinctoria, Koumac, New Caledonia, Oct, 1993. www.seaslugforum.net Photo: Bill Rudman.

Mutualism Clownfish and Sea Anemone

: Essentials of Oceanography, 4th ed. 199

From

Species Interactions  Interspecific

competition has a

negative effect on both species  Predation

and parasitism both

benefit one species at a cost to another

Alligator

Parasite “Cattle Tick”

Symbiosis  Living

together for at least some part

of the life cycle  Commensalism,

mutualism, and

parasitism are forms of symbiosis

Mutualism  Both species benefit  Many examples in nature  Some mutualisms are obligatory; 

partners depend upon each other

Yucca and Yucca Moth  Example  Each

of an obligatory mutualism

species of yucca is pollinated

only by one species of moth  Moth

larvae can grow only in that

one species of yucca

Yucca Moth Caterpillar

www.bobjensenphtography.com

Mycorrhizae  Obligatory

mutualism between

fungus and plant root  Fungus  Root

supplies mineral ions to root

supplies sugars to fungus

Laccaria bicolor basidioma developing on a Pinus strobus seedling under controlled environment.

Competition  Interspecific ­ between species  Intraspecific ­ between members of the 

same species  Intraspecific competition is most intense

River Otters Avoid Each Other Thus Reducing Intraspecific Competition

www.sms.si.edu

Forms of Competition  Competitors

may have equal access

to a resource; compete to exploit resource more effectively  One

competitor may be able to

control access to a resource, to exclude others

Elephants Exclude Competitors

www.save­the­elephants.org

Competitive Exclusion Principle When two species compete for identical resources, one will be more successful and will eventually eliminate the other

Competitive Exclusion Expt

Paramecium caudatum

Paramecium aurelia

Keystone Species A

species that can dictate community

structure  Removal

of a keystone species can

cause drastic changes in a community; can increase or decrease diversity

Lubchenco Experiment Periwinkles promote or limit diversity in different habitats

Tidepools

Rocks exposed at high tide

Resource Partitioning 

Apparent competitors may actually have slightly different niches



Species may use resources in a different way or time



Minimizes competition and

Predation  Predators are animals that feed on other 

living organisms  Predators are free­living; they do not 

take up residence on their prey

Coevolution  Natural

selection promotes traits that

help prey escape predation  It

also promotes traits that make

predators more successful at capturing prey

Predator-Prey Cycles  Predator

and prey populations may show an apparent correspondence PREY POPULATION

PREDATOR POPULATION

Variation in Cycles  An

association in predator and prey

abundance does not always indicate a cause and effect relationship  Variations

in food supply and

additional predators may also influence changes in prey abundance

Prey Defenses  Camouflage  Warning coloration  Mimicry  Moment­of­truth defenses

Predator Responses  Any

adaptation that protects prey

may select for predators that can overcome that adaptation  Prey

adaptations include stealth,

camouflage, and ways to avoid chemical repellents

Parasitism  Parasites drain nutrients from their 

hosts and live on or in their bodies  Natural selection favors parasites that 

do not kill their host too quickly

Types of Parasites  Microparasites  Macroparasites  Social

parasites

 Parasitoids

Micro and Macroparasites

Human tapeworm

Trypanosome, malaria

Social Parasites (STOPPED) Once limited to grasslands, brown - headed cowbirds have extended their range to all 48 contiguous states and Canada. They are a major threat to songbirds.

“Of 220 species known to have been parasitized by Brown-headed Cowbirds, and 144 have raised young Brown-headed Cowbirds successfully.” http://www.birds.cornell.edu/bfl/speciesaccts/parasites.html

Parasitoids

Chemical communication: Butterfly anti-aphrodisiac lures parasitic wasps

Male butterflies of the genus, Pieris, pass an anti-aphrodisiac during mating to females. This chemical, benzyl cyanide, renders the mated females less attractive to other males. This strategy tends to maximize the mating males chances of getting their genes into the next generation. Or so it was thought….

The Butterfly and its Parasitoid, Wasp

The Wasp highjacks the Sexual Communication Signal of the Butterfly

The female wasps are attracted to the anti-aphrodisiac of the mated female butterflies. Often they will hitch a ride on the female butterfly. When butterfly lays her eggs, the wasp inserts her egg into the butterfly egg. The larval wasp eats its host alive.

A Serve Limitation on the Butterfly Populations

This parasitism constrains the butterfly populations. “If this fascinating strategy is wide spread in nature, it could severely constrain the evolution of sexual communication between hosts.” The wasp is tiny (.5 mm) It is located below the eye Of the butterfly. NATURE|VOL433|17 FEBRUARY 2005| page 704

Fungus and Ants

 http://www.devilducky.com/media/5501

Bloodsucking leech spends month up Hong Kong hiker's nose

HONG KONG (AFP) - A Hong Kong woman hiker who washed her face in a freshwater stream unwittingly returned home with a leech embedded in her left nostril. “Doctors finally managed to remove it using a nasal spray to anaesthetise the five-centimetre-long (two-inch) bloodsucker a month after it had invaded her nostril.” 4/15/05

Succession Change in the composition of species  over time

Types of Succession  Primary

succession - new

environments  Secondary

succession -

communities were destroyed or displaced

Primary Succession

Sterile lava converted to a mature ecosystem overtime….

Secondary Succession

Over time, old fields are gradually and naturally converted to mature and healthy forests….example: Westminster’s forests.

Pioneer Species  Species

that colonize barren habitats

 Lichens,

small plants with brief life

cycles  Improve

conditions for other species

who then replace them

Climax Community  Stable

array of species that persists

relatively unchanged over time  Succession

does not always move

predictably toward a specific climax community; other stable communities may persist

Cyclic Changes  Cyclic,

nondirectional changes also

shape community structure  Tree

falls cause local patchiness in

tropical forests  Fires

periodically destroy underbrush

in sequoia forests

Restoration Ecology  Natural

restoration of a damaged

community can take a very long time  Active

restoration is an attempt to

reestablish biodiversity in an area  Ecologists

are actively working to

restore reefs, grasslands, and wetlands

Restoration Ecology

http://www.planetdrum.org/toc.htm

Community Instability  Disturbances can cause a community 

to change in ways that persist even if  the change is reversed

Species Introductions  Introduction

of a nonindigenous

species can decimate a community  No

natural enemies or controls

 Can

outcompete native species

Santa Cruz Fox and Feral Pigs

Species interactions

Exotic Species  Species that has left its home range 

and become established elsewhere  Becomes part of its new community  Can have beneficial, neutral, or harmful 

effects on a community

Don’t Worry About the Walking Catfish!

3.1 meter Burmese Python, Everglades NP

Predators in Paradise EVERGLADES NATIONAL PARK, Florida (CNN) (10/22/04) -- A dangerous intruder has invaded Everglades National Park, and it's putting the native wildlife at risk.

Shirt of missing camper!

How Big Do They Get?

http://www.cnn.com/2004/TECH/science/

Python Invasion Spawns Cottage Industry Python-Tracking Puppy Trains to Patrol Everglades  Stefan Lovgren for National Geographic News 

February 3, 2005  In their growing battle against giant pythons that have invaded the Florida Everglades, national park officials there have recruited an unlikely ally: a beagle puppy nicknamed "Python Pete." 

USGS Climate Map 2008

Areas of the continental United States with climate matching that of the pythons' native range in Asia. USGS image.

In the Belly of a Python  “Eight

pythons have been discovered in the Keys so far. The first was discovered alive in 2007  Federally endangered Key Largo woodrats were checking on the status of a male woodrat wearing a radio transmitter that had moved more than a mile from its original documented habitat.” http://www.nature.org/wherewework/northamerica/states/florida/science/art24101.html

From the Daily Show 

http://www.thedailyshow.com/video/index.jhtml?vide

Nile Monitors  “Recently

(Sept. 2005) a small population of around 1000 Nile Monitors have begun to rise in the area around Cape Coral Florida. They are most likely the offspring of a few Monitors let free by local pet owners.”



http://en.wikipedia.org/wiki/Nile_monitor

Nile Monitor

http://en.wikipedia.org/wiki/Nile_monitor

Wis. Considers Legalizing Cat Hunting

Recently in the news (4/15/05)

Wis. Residents Seek Legalized Cat Hunting Feral cats, which volunteers have been feeding for the past 10 years, feed in Anoka, Minn., Feb. 21, 2005. A new Wisconsin plan would declare free-roaming wild cats an unprotected species, just like skunks or gophers. Anyone with a smallgame license could shoot the cats at will, legally. The proposal gets tested April 11 at the Wisconsin Conservation Congress spring hearings, where outdoor enthusiasts gather in every county to vote on hunting and fishing issues. (AP Photo/St. Paul Pioneer Press, Joe Rossi)

Africanized Killer Flea Invasion  ATLANTA—Panic is spreading among American dog owners, following the Center for Veterinary Medicine's Monday announcement that the arrival of a deadly mutant strain of Africanized killer fleas is imminent.

Crossed Texas Border in 2004 Bred in Brazil at the Sao Paulo Animal Research Facility in the late '60s, Ctenocephalides canis africanus is a crossbreed of the common North American flea and an African variant that infests the tough hides of bull elephants. The Sao Paulo entomologists never meant to release the mutant fleas into the wild, but a 1974 fire at the lab led to the dangerous subspecies' escape. In the past 30 years, Africanized fleas spread from Brazil to South and Central America and on to Mexico.

Asian Invasion  Asian

carp in the Mississippian drainage system  Escaped from cultivation into the lower Mississippi some years ago.  Expanding their range northward to the Great Lakes  Go to Youtube for videos

Endangered Species A

species that is extremely

vulnerable to extinction  Close

to 70 percent of endangered

species have been negatively affected by exotic competitors

Georgia’s Endangered and Threaten Plants  

Plants -- 22 StatusListingTAmphianthus, little ( Amphianthus pusillus) ERattleweed, hairy ( Baptisia arachnifera)EConeflower, smooth ( Echinacea laevigata)TPink, swamp ( Helonias bullata)EQuillwort, black spored ( Isoetes melanospora)EQuillwort, mat-forming ( Isoetes tegetiformans)TPogonia, small whorled ( Isotria medeoloides)EPondberry ( Lindera melissifolia) TButton, Mohr's Barbara ( Marshallia mohrii)EDropwort, Canby's ( Oxypolis canbyi)EHarperella ( Ptilimnium nodosum)ESumac, Michaux's ( Rhus michauxii) TWater-plantain, Kral's ( Sagittaria secundifolia)EPitcherplant, green ( Sarracenia oreophila)EChaffseed, American ( Schwalbea americana)ESkullcap, large-flowered ( Scutellaria montana)ECampion, fringed ( Silene polypetala) TSpiraea, Virginia ( Spiraea virginiana)ETorreya, Florida ( Torreya taxifolia)ETrillium, persistent ( Trillium persistens) ETrillium, relict ( Trillium reliquum)EGrass, Tennessee yellow-eyed ( Xyris tennesseensis)

http://www.endangeredspecie.com/states/ga.htm

International Problem  Nile

perch in Africa  Rabbits in Australia  Toads in Australia  Frogs in Hawaii

Nile Perch in East Africa  Nile

perch were introduced into Lake

Victoria as a food source  This

predator ate native cichlids;

drove many species to extinction  Now

Nile perch species is close to

crashing

Nile Perch

They have put tremendous pressure On native species.

Nile Perch  Food

fish

Rabbits in Australia  Rabbits

were introduced for food and

hunting  Without

predators, their numbers

soared  Attempts

at control using fences or viruses have thus far been unsuccessful

Rabbits in Australia

Rabbits were hunted

Environment minister endorses violent means to slow toxic toads' spread across Australia 

Campbell endorsed the bloody response advocated by the government lawmaker who represents Darwin, David Tollner. Tollner created public outrage last week when he said the best way to stop the toads' spread was to bludgeon them on the head with golf clubs or cricket bats as he did as a child. (Thursday April 14, 9:51 PM AP News)

The Response is Mixed…  “Australia's

foremost animal welfare agency, the Royal Society for the Prevention of Cruelty to Animals, responded by warning that anyone caught causing pain and suffering to a cane toad could be fined or jailed.  Animal welfare groups say the best way to kill them is to freeze them.”

Cane Toads Native to South and Central America Cane Toads, the video

A handful of trouble….

Coqui & greenhouse frogs: alien Caribbean frogs in Hawaii

“Non-native Caribbean frogs* have become established in some areas in Hawaii (*coqui and greenhouse frogs: Eleutherodactylus spp. [not true 'tree frogs', as some have called them]). They cause both environmental problems and problems for people. These creatures have a special appeal to some people; however, these frogs are not native to Hawaii, and their existence in Hawaii poses a great threat to native species in Hawaii . Although the call of the coqui is often beloved by residents of the coqui's native habitat, the extremely loud noise they make in Hawaii (presumably louder than in native habitats because of higher concentrations of populations) has been reported to be extremely annoying to numerous Hawaii residents and visitors. (For example, a recent article in a health-related magazine cites coqui as causing sleepless nights on the island of Oahu.)” http://www.hear.org/AlienSpeciesInHawaii/species/frogs/#frogc Coqui chorus …..

Bills Seek to Muffle Isle Frog

“The frog -- which subsists on the same diet of insects as native birds -- could be the greatest threat to state's ecosystem that anyone has ever seen before, Kim said.” http://starbulletin.com/2005/02/13/news/story12.html

Problems in Georgia  Cuban

Tree Frogs  Asian Swamp Eels  Kudzu  Privet

Cuban Tree Frog Found In Georgia “Butler's capture of a 4½-inch Cuban tree frog in coastal Savannah has caused a nervous stir among wildlife biologists in Georgia and Florida…. …Since its discovery in Key West, Fla., in the 1920s, the Caribbean frog has been considered an unwanted predator that disrupts ecosystems by dining on native species - including smaller tree frogs.” http://www.cbsnews.com/stories/2004/10/21/tech/main650682.shtml

Cuban Tree Frog  "They're

(a) huge relative to our native frogs," said John Jensen, Georgia's state herpetologist with the Department of Natural Resources. "Like pretty much all frogs, they eat anything they can catch and fit in their mouths."  http://www.cbsnews.com/stories/2004/1 Picture link

USGS SCIENTISTS FIND NEW INVASIVE FISH SPECIES IN FLORIDA (Georgia too!) “In North America, the species is sometimes kept as an aquarium fish, although scientists can only speculate that the species may have escaped or been released into the state's waters. In 1995, swamp eels were found in several ponds at the Chattahoochee Nature Center north of Atlanta, Ga.”

Asian Swamp Eel

http://cars.er.usgs.gov/Nonindigenous_Species/Swamp_eel_FAQs

Grow up to 3.5 ft long…

Monopterus albus “It breathes air and can move across land. This gives it the potential to spread rapidly and makes control difficult.”

Kudzu in Georgia  Imported

for erosion control

 No

natural herbivores, pathogens, or competitors

 Grows

over landscapes and cannot be dug up or burned out

 May

turn out to have some commercial use

Kudzu

Poem About Kudzu by James Dickey   

 

ALL: Kudzu Japan invades. Far Eastern vines Run from the clay banks they are Supposed to keep from eroding. Up telephone poles, Which rear, half out of leafage As though they would shriek, Like things smothered by their own Green, mindless, unkillable ghosts. In Georgia, the legend says That you must close your windows At night to keep it out of the house. The glass is tinged with green, even so, As the tendrils crawl over the fields. … and so on …

http://www.breakoutofthebox.com/kudzu.htm

Assignment Earth Videos  Asian

Longhorned Beetle  http://cosmos.bcst.yahoo.com/up/player http://cosmos.bcst.yahoo.com/up/playe  Gopher

Tortoise  http://cosmos.bcst.yahoo.com/up/player http://cosmos.bcst.yahoo.com/up/playe

Assignment Earth Videos  Water

Wars  http://cosmos.bcst.yahoo.com/up/player http://cosmos.bcst.yahoo.com/up/playe  Copper

Basin Cleanup  http://cosmos.bcst.yahoo.com/up/player http://cosmos.bcst.yahoo.com/up/playe

Assignment Earth Videos  Suburban

Coyotes  http://cosmos.bcst.yahoo.com/up/player  Savannah

River Sturgeons  http://cosmos.bcst.yahoo.com/up/player

Final Topic Diversity by Latitude  Diversity of most groups is greatest in 

tropics; declines toward poles

Ant  diversity

Why Are Tropical Species Rich?  Resources are plentiful and reliable    Species diversity is self­reinforcing  Rates of speciation are highest in the 

tropics

Distance Effect  The

farther an island is from a

mainland, the fewer species  Closer

islands receive more

immigrants  Species

that reach islands far from

mainland are adapted for longdistance dispersal and can move on

Distance Effect