Ways to categorize groups of populations (from Fauth et al . 1996)

2. 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 community: all organisms at a location ensemble hyphenated assemblage taxa: phylogenetically related organisms

3. 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

4. Major Aquatic Habitats & Communities  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

5. Within-Lake Zonation  First distinction: pelagic zone vs. bottom  Pelagic zone (pelagia) is the open water column  Bottom can be further subdivided

6. epilittoral spray zone supralittoral spray & waves between high & low water eulittoral upper littoral; emergent veg littoral pelagia middle littoral; floating veg lower littoral; submerged veg littoriprofundal; photosynthetic bacteria & algae profundal; no vegetation or algae Within-Lake Zones

7. plankton nekton benthos

8. River habitats pool: deep, slow velocity, fine substrates run: between pool & riffle riffle: shallow, high velocity, gravel cobble substrate flow R P P R P R R P gravel bars R P P P R

9. Oceans most of the worlds water, most of earth’s surface area

10. Oceanic habitats littoral zone neritic waters photic zone -130m continental shelf aphotic zone continental slope mid oceanic ridge - 4,500m abyssal plain - 10,000m trench

11. Miscellaneous aquatic habitats Natural  ponds: can be permanent or ephemeral  tree trunks: especially in rainforests  pitcher plants: hold simple invertebrate communities Man made ponds drainage areas

12. What interactions among the species adapted to live in a particular place affect the observed community of that place?

13. Types of interactions between species consumer - resource interactions  consider direction and effect resource consumer + predation - + - competition - - +

14. 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.

15. Categories of competition intraspecificcompetition: between members of same spp  density dependent population regulation  evolutionary change resources scarce, competition population size K= # that resources can support Time

16. interspecific competition: occurs between members of different species (community)  mutually depressing effect on both populations  depends on relative efficiency of each population

17. 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,

18. Strayer & Lane suggest exploitative competition is more important in the Hudson River even though there is often fouling zebra mussels found in Hudson in 1991 and became common by 1992 1991 & 92= low zm, 1993- 95=high zm 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

19. Zebra mussel infestation of unionids is low in the Hudson expected #/clam based on observations in other systems number observed in Hudson expected proportion infested clams infested proportion observed in Hudson

20. but ……. clams are still dying Elliptio complanata most common spp white = live clam black = dead clam Anodonta implicata Leptodea ochracea low high

21. Three possible explanations 1) 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

22. 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

23. 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

24. Most Cladocerans filter feed carapace gape thorasic legs Diaphanosoma Ceriodaphnia  Lower particle size determined by how fine ‘spines’ are on filtering comb  Upper size set by width of mandibles or carapace gape Chydorus http://www.cnas.smsu.edu/zooplankton

25. Most copepods are raptorial (bite off chunks) Diacyclops Diaptomus Acanthocyclops Can use ‘taste’ chemical properties to discriminate particles

26. In class 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?

27. Periphyton grazers some fish Megalancistrus aculeatus, photo by K.S. Cummings http://george.cosam.auburn.edu/usr/key_to_loricariidae/lorhome/lorhome.html Pterygoplichthys scrophus (formerly Glyptoperichthys) Photo by L.M. Page scraping mouth parts Stoneroller (Campostoma anomalum) http://www.dnr.cornell.edu/sarep/fish/Cyprinidae/stoneroller.html

28. many tadpoles scraping mouth parts http://www.whose-tadpole.net/key-to-tadpoles/R-temporaria-LARVAE.htm Many invertebrates: snails scrape w/ radula caddis fly larvae w/ blade-like mandiles mayflies w/ chewing mouth parts w/ brush-like structures

29. Predation (animals that eat animals) Encounter Attack Capture Ingestion probability predation=PE*PA*PC*PI P always <1.0, all must happen

30. Encounter Ambush: Wait for prey to come to you. Burst speed. Pike, muskie, barracuda, gar, many camouflaged fish, Chaoborus, dragonfly larvae. Lepisosteus osseus http://fcn.state.fl.us/fwc/fishing/Fishes/gar.html Rover: Actively search for food. Constant motion. Bass, perch, copepods, some insect larvae.

31. Odonate larvae mentum extends to grasp prey http://insects.ummz.lsa.umich.edu/michodo/test/index.htm Attack:  forward (most fish) or sideways (gar) lunge  special grasping organs Capture:  prey have adaptation to avoid capture  piscivores have lots of teeth two prey fish have different efficiency of capture and handling time

32. Selectivity proportion of prey in diet proportion of prey in environment ri / pi  = m  (ri / pi) sum of proportions for m prey items I=1 X 10 X 6 X 10 Put a bass in a tank w/ above fish. It eats 3 goldfish, 1 bluegill & 3 herring. Calculate selectivity for each.

33. Planktivory  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  most fish selectindividual particles reaction distance changes with characteristics of the prey and environmental conditions  adult fish tend to select largest, most visible prey, most energy return.

34. Planktivorous fish tend to shift the size distribution of plankton to smaller animals Brooks & Dodson 1965 before plantivore introduced after introduction  Benthic fish are also size selective; more variability in the strength of the effect of predation on benthic invertebrates.

35. Invertebrate Predators Encounter: Most use mechanical or chemical means of detection (a few use vision like fish) Attack strategies 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

36. Invertebrate predators are not much bigger than their prey (compared to adult fish) probability of encounter is greater for bigger prey But larger prey are harder to subdue and handle So Invertebrates may preferentially consume intermediate sized prey

37. Defenses of prey Coloration: reduce visibility zooplankton are very clear benthos 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

38. be hard to eat: works best against invertebrate predators or very small fish  gelatinous sheath  protuberances D. ambigua D. lumholtzi D. retrocurva

39. 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 “ “

40. 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

41. examples of costs There’s almost always a trade off (no free lunch)  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  Stream invertebrates must deal with fish (visual) and predatory invertebrates (tactile), good defense for fish may make you vulnerable to inverts.

42. Symbiosis: unlike organisms living together parasitism (one benefits, at expense of other) commensalism (one benefits, other unaffected) mutualism (both benefit) coral & algae sea lamprey

43. ectoparasites: found on the outside of hosts Epibionts common on Daphnia, including ciliates. http://www.unibasel.ch/dib/zoologie/ebert/hostpara/daphpato.html endoparasites: found on the inside of hosts 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

44. 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 Erie until 1921  Thereafter invasion quickened; found in Lake Huron in 1932, Lake Michigan in 1936, and Lake Superior in 1946.

45.  Lampreys devastated lake trout populations in Great Lakes  Removal of top predator allowed smaller fish such as alewife (also introduced through canals) to boom http://www.glfc.org/slft.htm  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

46. coral - dinoflagellate association coral = 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.

47. 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 temperature increased UV-B eutrophication & sedimentation

48. Ecosystem Engineers 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  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

49. Engineers as keystone species keystone species: dominating influence on community, usually regarded as a trophic interactor autogenic engineers keystone predator allogenic engineers http://life.bio.sunysb.edu/marinebio/kelpforest.html