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Stream Ecology SWES/WFSC/ECOL 471/571

Stream Ecology SWES/WFSC/ECOL 471/571. Dr. David Walker Dr. William Matter. Definitions. … a given discipline cannot readily develop without precise categorization of language.

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Stream Ecology SWES/WFSC/ECOL 471/571

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  1. Stream Ecology SWES/WFSC/ECOL 471/571 Dr. David Walker Dr. William Matter

  2. Definitions • …a given discipline cannot readily develop without precise categorization of language. • …one of the fundamental aims of science must be the isolation of semantic categories so that these defined units can serve as a basis for empirical permutation. Balgooyen, 1973

  3. The Art of Meaningless…ness • PeripatheticadjMoping about or from place to place; whining while walking.Having failed to convince us that the loss of her mall privileges was a terrible crisis, my peripathetic sister moved on to try and convince another group of friends in the cafeteria. • SarcastrophenounThe embarrassing and catastrophic results of a failed attempt at sarcasm. "Oh yeah, like blowing up Afghanistan is going to end terrorism. We might as well just invade Iraq!" - U.S. National Security Advisor, 2003. • MelancholeranounA form of the disease cholera characterized by extreme depression and sadness.I hate life, I hate my parents, I have everything, but I'm too sick to put on my black lipstick. • SpatulencenounThe abrupt expulsion of cooking utensils from one's body cavity.  My spatulence produced several nice melon ballers today. • From Decombust.com

  4. So…what is “ecology”? • German Ökologie, from öko- eco- + -logie -logy • Eco-, Gr. oiko-, oikos, house

  5. History • Ernst Haeckel coined the term ecology in the mid-19th century. • The Haeckelian definition emphasized biotic and abiotic components of the natural world and that organisms are the relevant manifestation of the biotic realm. • Largely neglected inconspicuous organisms, such as microbes, and ecological systems at higher hierarchical levels than organisms.

  6. H.G. Andrewartha and L.C. Birch • Emphasized both abiotic and biotic factors influencing distribution and abundance of species. • Still had a predominately biotic focus. • Introduced the concept of “metapopulations”. • Several distinct populations together within areas of “currently unoccupied suitable habitat”.

  7. Systems Ecology: “Ecosystems” • Provided several statements on the scope of ecology. • Major emphasis on structure and function of ecosystems. • Both believed in the idea of a “superorganism” and went to great lengths to try and quantify as many different energy pathways and interactions as possible.

  8. For our purposes… • An ecosystem is a conceptual unit comprised of an assemblage of organisms, their interactions with each other and their environment, and having the major attributes of: • Structure and function • Complexity • Inter-action and inter-dependency • Temporal change • No inherent definition of spatial dimension

  9. What is ecosystem structure and function? • Two distinct camps in ecosystem scientists: those concerned with measuring inputs and outputs and those concerned with specific populations. • Usually, ecosystems are defined first by the biota and second by the environment. • In any ecosystem, patterns of organization at almost any spatial or temporal scale are common. • But are these organizational patterns considered “structure”?

  10. Structural pattern should (must?) be tied to those functions that are critical for the evolutionarily-derived operation of the ecosystem. • Structure derives from function. • Structure is the minimal or parsimonious pattern of organization necessary for a function to operate.

  11. The Big Picture Evolutionary Theory Ecology Systems Ecology Ecosystems

  12. The Stream Environment: Categorical Units

  13. Watersheds Hydrologically-bound units based upon topography. Larger watersheds composed of several “sub-watersheds” or smaller drainages.

  14. Since whatever happens up-stream affects everything downstream, watershed management is increasingly used by resource agencies as a more integrated approach to solving water quality problems.

  15. A watershed is… "that area of land, a bounded hydrologic system, within which all living things are inextricably linked by their common water course and where, as humans settled, simple logic demanded that they become part of a community." • John Wesley Powell

  16. Stream Order A hierarchical classification system of stream segments (R.E. Horton, 1945). Segments are ordered numerically from headwaters to reach so that individual tributaries at the headwaters were given the order of “1”. The joining of two 1st order streams were given the order of “2” and the joining of two 2nd order streams the 3rd order and so on.

  17. 1) Stream length increases with stream order. 2) There are 3-4 times as many streams of the order n-1 as there are of n

  18. Problems with Stream Order Classification Difficult to identify first order streams. Leopold et al (1964) suggest that first order streams should be considered the smallest ones marked on a 1:24,000 scale map. Does this have any ecological significance? Stream order classifications ignore the entry of streams n into n + 1.

  19. Streams systems exhibit a large degree of spatial variability from headwater to reach to mouth. Classification schemes work well for communicative purposes.

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