ways to categorize groups of populations (from fauth et al . 1996)
DESCRIPTION
detritus feeding caracidae (family of fish) in an Andean stream. Lake Michigan piscivores. pond-breeding salamanders. Lake Baikal zooplankton. Ways to categorize groups of populations (from Fauth et al . 1996). guild: organisms that use a shared resource. local guild. - PowerPoint PPT PresentationTRANSCRIPT
Ways to categorize groups of populations(from Fauth et al. 1996)
guild: organisms that use a shared resource
ensemble
assemblage
taxa: phylogenetically related organisms
hyphenated
Lake Baikal zooplankton
pond-breeding salamanders
local guild
Lake Michigan piscivores
community: all organisms at a location
detritus feeding caracidae (family of fish) in an Andean stream
Community vs Ecosystem
Community = all organisms in area
Ecosystem = all organisms + physical properties of area (rocks, sunlight, weather……)
community structure: types of species, trophic relationships, physical characteristics
community function: rate of energy flow, resilience to perturbation, productivity
Lakes; pelagic, littoral, benthic- more later on types of lakes
Rivers; habitat defined by flow and depth
Estuaries; meeting of river & ocean
Wetlands; defined along gradients- more later
Oceans; most of world’s water- pelagic, littoral, benthic
Miscellaneous habitats; many small out of the way places
Major Aquatic Habitats & Communities
Within-Lake Zonation
First distinction: pelagic zone vs. bottom
Pelagic zone (pelagia) is the open water column
Bottom can be further subdivided
epilittoral
supralittoraleulittoral
spray zone
spray & wavesbetween high & low water
upper littoral; emergent veg
middle littoral; floating veg
lower littoral; submerged veg
littoriprofundal; photosynthetic bacteria & algae
profundal; no vegetation or algae
litto
ral
pelagia
Within-Lake Zones
planktonnekton
benthos
River habitats
pool: deep, slow velocity, fine substrates run: between pool & riffle riffle: shallow, high velocity, gravel cobble substrate
RR
R R
P PP P
flow
P R
P R
P
gravel bars
Oceans
most of the worlds water, most of earth’s surface area
- 4,500m
- 10,000m
-130m
photic zone
littoral zone
neritic waters
continentalshelf
continentalslope
abyssal plain
mid oceanic
ridge
trench
aphotic zone
Oceanic habitats
Miscellaneous aquatic habitats
Natural ponds: can be permanent or ephemeral tree trunks: especially in rainforests pitcher plants: hold simple invertebrate communities
Man madepondsdrainage areas
What interactions among the species adapted to live in a particular place affect the observed community of that place?
Types of interactions between species
consumer - resource interactions
resource consumer
+
-
predation
+
+
competition-
-
consider direction and effect
-
resource consumer
+ mutualism
+
Interactions that involve habitat modification
direction and effect vary depending on interaction
Consider a steam with a beaver dam. Beaver changes stream (lotic habitat) to pond (lentic habitat) & changes some terrestrial habitat to aquatic. The beaver affects every organism living in the area. Doesn’t involve consumption of resources.
Categories of competition
intraspecific competition: between members of same spp density dependent population regulation evolutionary change
Time
po
pu
lati
on
siz
e
K= # that resources can support
resources scarce, competition
interspecific competition: occurs between members of different species (community)
mutually depressing effect on both populations depends on relative efficiency of each population
Interference competition: one individual directly interferes with another’s access to a resource
Chemical: some organisms release chemicals that have negative effect on others- not that common in freshwater
Mechanical: have negative effects due to physical contact
settlement space in marine littoral and streams, maybe lakes too, zebra mussels & native unionids foraging territory defence
Exploitative competition: individuals use the same resource, but at different times,
Strayer & Lane suggest exploitative competition is more important in the Hudson River even though there is often fouling
1991 & 92= low zm, 1993- 95=high zm
zebra mussels found in Hudson in 1991 and became common by 1992
Strayer and Lane. 1998 . Effects of the zebra mussel (Dreissena polymorpha) invasion on the macrobenthos of the freshwater tidal Hudson River. Can. J. Zool. 76(3): 419–425
Zebra mussel infestation of unionids is low in the Hudson
expected #/clam based on observations in other systems
number observed in Hudson
infested proportion observed in Hudson
expected proportion infested clams
but ……. clams are still dying
white = live clamblack = dead clam
Elliptio complanatamost common spp
Anodonta implicata
Leptodea ochracea
low high
Three possible explanations1) decline in live clams part of natural population cycle
long lived 3 spp breed at different times of year, all affected same way
2) even very low fouling can be leathal
many dead shells had no evidence of zebra mussel attachment (byssal threads)
3) zebra mussels out compete unionids for food
phytoplankton 10 -20 % of 1986-1991 levels
Conservation implications
Unionid population at risk identified by level of zebra mussel infestation
May also need to look at populations that experience decline in food level
Ways that aquatic organisms avoid competition
Environmental specialization: ex paradox of the plankton
Habitat partitioning: rotifers & Chydoridae
Resource partitioning: Daphnia vs copepod approach to feeding, live in the same place but use different resources
See pages 166-168 in Dodson
Most Cladocerans filter feed
Ceriodaphnia
Chydorus
Diaphanosoma thorasic legs
Lower particle size determined by how fine ‘spines’ are on filtering comb Upper size set by width of mandibles or carapace gape
http://www.cnas.smsu.edu/zooplankton
carapace gape
Most copepods are raptorial (bite off chunks)
DiacyclopsDiaptomusAcanthocyclops
Can use ‘taste’ chemical properties to discriminate particles
When spp coexist in nature they usually differ somewhat in the way they utilize resources and thus avoid competitive exclusion. Suppose that there are 2 species of chironomid larvae in a pond you are studying. They are the same size, are both active during the same time of day, and live in the same kind of sediment. Explain the observations or experiments that you would undertake to determine how their ecology differed.
How do you explain their coexistence if you can’t find a difference?
In class
Pterygoplichthys scrophus (formerly Glyptoperichthys) Photo by L.M. Page
Megalancistrus aculeatus, photo by K.S. Cummings
scraping mouth parts
Periphyton grazers
http://www.dnr.cornell.edu/sarep/fish/Cyprinidae/stoneroller.html
Stoneroller (Campostoma anomalum)
http://george.cosam.auburn.edu/usr/key_to_loricariidae/lorhome/lorhome.html
some fish
many tadpoles
scraping mouth parts
http://www.whose-tadpole.net/key-to-tadpoles/R-temporaria-LARVAE.htm
Many invertebrates:
snails scrape w/ radulacaddis fly larvae w/ blade-like mandilesmayflies w/ chewing mouth parts
w/ brush-like structures
Predation (animals that eat animals)
Encounter
Attack
Capture
Ingestion
probability predation=PE*PA*PC*PI
P always <1.0, all must happen
Encounter
Ambush: Wait for prey to come to you. Burst speed. Pike, muskie, barracuda, gar, many camouflaged fish, Chaoborus, dragonfly larvae.
Rover: Actively search for food. Constant motion. Bass, perch, copepods, some insect larvae.
http://fcn.state.fl.us/fwc/fishing/Fishes/gar.html
Lepisosteus osseus
Attack: forward (most fish) or sideways (gar) lunge special grasping organs
http://insects.ummz.lsa.umich.edu/michodo/test/index.htm
Odonate larvae mentum extends to grasp prey
Capture:
prey have adaptation to avoid capture piscivores have lots of teeth
two prey fish have different efficiency of capture and handling time
Selectivity
=ri / pi
(ri / pi)
proportion of prey in diet proportion of prey in environment
sum of proportions for m prey itemsm
I=1
X 6 X 10 X 10
Put a bass in a tank w/ above fish. It eats 3 goldfish, 1 bluegill & 3 herring. Calculate selectivity for each.
Almost all fish eat zooplankton early in development
some filter (like a strainer), alewife, gizzard shad & the baleen whales (really really big mammals)
Blue Whale 100 ft, up to 220 tons
http://www.calpoly.edu/~jiturrir/ED480/whales/baleen.html
Planktivory
most fish select individual particles
reaction distance changes with characteristics of the prey and environmental conditions
adult fish tend to select largest, most visible prey, most energy return.
Benthic fish are also size selective; more variability in the strength of the effect of predation on benthic invertebrates.
Planktivorous fish tend to shift the size distribution of plankton to smaller animals
before plantivore introduced
after introduction
Brooks & Dodson 1965
Invertebrate Predators
Most use mechanical or chemical means of detection (a few use vision like fish)
Attack strategies
Encounter:
engulfers: ingest all or most of prey in chunks or whole; most invertebrates, prey usually smaller than predator
pierces: inject digestive enzymes and ingest prey in liquid form; backswimmers, some beetles, leeches; prey can be larger than predator
Invertebrate predators are not much bigger than their prey (compared to adult fish)
probability of encounter is greater for bigger prey
larger prey are harder to subdue and handle
But
Invertebrates may preferentially consume intermediate sized prey
So
Defenses of prey
Coloration: reduce visibility
zooplankton are very clearbenthos have other cryptic colors
Don’t make waves
Bosmina plays dead trade off between feeding and avoiding detection
http://www.cnas.smsu.edu/zooplankton/bosmina.htm
be hard to eat: works best against invertebrate predators or very small fish
gelatinous sheath protuberances
D. ambigua
D. retrocurvaD. lumholtzi
Benthic organisms stay close to the bottom
hide in crevasses make burrows make cases
Timing of activity
time drift when visual feeding fish least efficient time grazing “ “
The cost of defense
constitutive: always turned on
snail shell constant or unpredictable predation no too costly to make
induced: only turn on when threat of predation detected
change in zooplankton body size (mostly) periodic or predictable predation don’t incur the cost till you need it
examples of costs
Energy spent constructing case, shell, body protrusion not devoted to reproduction & may take extra energy to swim
Time spent hiding not spent foraging, avoid death, but lower growth & reproduction
There’s almost always a trade off (no free lunch)
Stream invertebrates must deal with fish (visual) and predatory invertebrates (tactile), good defense for fish may make you vulnerable to inverts.
parasitism(one benefits, at
expense of other)
commensalism (one benefits,
other unaffected)
mutualism (both benefit)
Symbiosis: unlike organisms living together
sea lamprey coral & algae
ectoparasites: found on the outside of hosts
endoparasites: found on the inside of hosts
Epibionts common on Daphnia, including ciliates.
http://www.unibasel.ch/dib/zoologie/ebert/hostpara/daphpato.html
D pulex w/ fungal infection. Fungus grows inside the body cavity and penetrates into all organs and into the extremities.
http://www.unibasel.ch/dib/zoologie/ebert/hostpara/daphpato.html
The Sea Lamprey(Petromyzon marinus)
Native to the Atlantic Ocean Probably entered Great Lakes via the Hudson River and its artificial extension, the Erie Canal (opened to Lake Ontario in 1819)
Gained access to Lake Erie through Welland Canal around Niagara Falls (completed 1829), but not noted in Lake Erieuntil 1921 Thereafter invasion quickened; found in Lake Huron in 1932, Lake Michigan in 1936, and Lake Superior in 1946.
http://www.glfc.org/slft.htm
Lampreys devastated lake trout populations in Great Lakes
Removal of top predator allowed smaller fish such as alewife (also introduced through canals) to boom
Lamprey control (pesticide applied to juvenile form in streams)
Coho & Chinook salmon easier to grow in hatcheries than lake trout. These exotic species were heavily stocked
coral - dinoflagellate associationcoral = invertebrate, phylum Cnidaria
dionoflagelate = unicellular algae (photosynthetic protist) called zooxanthellae
Coral animal gets photosyntheticly produced carbon, algae may also speed production of calcium carbonate in reef producing corals
Algae gets metabolites and and some protection from coral.
soft coral,Xenia, w/ zooxanthellae http://207.254.123.101/solarpow.htm.
Coral reefs widespread and important in marine systems
Many organisms associate with structure formed by reefs (ecosystem engineers) Recent events of coral bleaching (lose of zooxanthellae) related to
rise in ocean temperatureincreased UV-Beutrophication & sedimentation
Organisms that directly or indirectly modulate the availability of resources other than themselves to other species, by causing physical state changes in biotic or abiotic materials. In so doing, they modify, maintain and or create habitats
Jones et al. 1994
Ecosystem Engineers
Examples extensively studied, e.g. beaver, but only recently recognized as important category of interactions
http://sevilleta.unm.edu/data/species/mammal/profile/american-beaver.html
Engineers as keystone specieskeystone species: dominating influence on community, usually regarded as a trophic interactor
autogenic engineers
allogenic engineers
keystone predator
http://life.bio.sunysb.edu/marinebio/kelpforest.html