News

1. News • Guns in National Parks • GSMNP • Python bounty hunters

2. Ecosystems Ecology -- Interactions between living and nonliving elements that sustain life • Biotic community • Living parts of an ecosystem • Ecosystem • Affected by external/internal factors • Perturbations • Fire, hurricanes, insects, over grazing, timbering • Anthropogenic or “natural” • All recovering from some past disturbance • Nothing is constant except change • Everything is connected to everything else • Limits difficult to define

3. Ecosystems • Perturbations (disturbance) • Anthropogenic • DDT killed bugs, but also thinned egg shells of eagles, falcons, etc. • Chernobyl • 10% fallout over Sweden • Lichens “radiation sponges” • Symbiotic fungus and algae • Wildlife haven?? • Spills, atmospheric deposition • Natural? disturbance

4. Ecosystems • Scale • Large • Biosphere • Biome • Smaller • Longleaf pine forest • Regenerating stand • Smaller still • Single tree • Boundaries difficult to define

5. Ecosystems • Self sustaining? • Entropy • Second Law of Thermodynamics • Entropy tends to increase over time • Entropy is a measure of disorder (and order) • the higher the entropy the greater the disorder • Nature should inexorably degenerate toward a state of greater disorder, greater entropy • So how are living systems ordered? • Energy is required • Ordering must be balanced with disorder (closed system) • Ecosystems must be open systems -- connected

6. Ecosystems • Cities don’t qualify as ecosystems? • Not self-sustaining? • Because they import a lot of energy • Raw materials transformed but little replenished • But ecosystems couldn’t be sustained either w/o a lot of energy input • Wildfire transforms, does it replenish? • Do cities meet the definition of ecosystem? • If it takes a lot of human interference, then it’s not an ecosystem?

7. Manipulate Ecosystems • Wildlife management intentionally manipulates communities and ecosystems (to achieve a goal) • That’s why the chapter seems to focus on disturbance

8. Matter and Energy • Carbon based • Organic chemistry • Photosynthesis • CO2 + H20 = sugars + O2 • Galapagos Rift • Volcanic hydrothermal vents • Sulfur-based life • Chemoautotrophic bacteria • Hyperthermophiles • SLMEs • Subsurface lithoautotrophic microbial ecosystems

9. Food (Chains) Webs • All require energy and matter • Trophic levels • Primary producers - autotrophs • Plants • Consumers • Primary consumers • Herbivores • Secondary • Carnivore • Tertiary • Top level carnivores • Decomposers

10. Food (Chains) Webs • Trophic pyramid • Represent flow of energy • 10% efficient • Biomass too • Inverted pyramid • Aquatic phytoplankton and zooplankton • Small biomass of autotrophs supports a large mass of longer lived herbivores • Rapid turnover of autotrophs • Detritus based -- energy of mountain streams from outside • Can’t have a lot of top level carnivores

11. Energy Transfer • Less energy (per unit area) at each level of the trophic pyramid • Plants > Herbivores > Carnivores • Prey populations limit the number of predators, not vise versa • Eat low on the food chain • Length of the food chain is limited

12. Energy Transfer Isle Royale • 1 kg wolf : 59 kg moose : 765 kg browse • Wolf = 50 kg Moose = 300 kg • Wolf needs to eat about 10 moose per wolf per year • Striper fisherman at Lake Norman • Want lots of large stripers • So they want to stock more stripers • Does this make any sense?

13. Range of Tolerance (Ecological Amplitude) • Temperature, moisture, heat, salinity,… • Halophytes • Steno -- narrow • Stenophagus -- Everglades kite • Stenoky -- RCW • Eury -- wide • Eurythermal • Euroky • Euryphagus -- wild pigs

14. Thermoneutral Zone • Zone of ambient temperature defined by upper and lower critical limits. Within this zone metabolism is at the basal rate. • Outside this range metabolism increases to maintain body temperature. • Beaver example

15. Circadian rhythms • A circadian rhythm is an approximate daily periodicity, a roughly 24-hour cycle in the biochemical, physiological or behavioral processes of living beings, including plants, animals, fungi and cyanobacteria. • Circadian rhythms are endogenously generated, and can be entrained by external cues, called Zeitgebers. The primary one is daylight.

16. Circadian rhythms • The rhythm is linked to the light-dark cycle. Animals, including humans, kept in total darkness for extended periods eventually function with a freerunning rhythm. Each "day," their sleep cycle is pushed back or forward, depending on whether their endogenous period is shorter or longer than 24 hours. The environmental cues that each day reset the rhythms are called Zeitgebers (from the German, Time Givers)

17. Niche • Animal’s “profession” Habitat “address” • Multidimensional hyperspace • Climatograph 2 dimensions (temp, rain) • Generalists vs. specialists • Euroky vs. stenoky • Sympatric species • Spruce grouse -- winter diet jack pine needles • Ruffed grouse -- aspen catkins • Ecological equivalent • Capercaillie -- Scot’s pine in Europe • Robin vs. Woodcock

18. Niche • Damaged ecosystems • Do they have the original niches? • Two species cannot occupy the same niche at same place and time • Empty niche? • Exotic species • Feral cats • Out compete native species • Examples?

19. Changes in Space and Time • Spatial • Biomes -- climate determined • Dominant plants • Grassland, deciduous forest • Temporal • Succession • Primary vs. secondary • Successional sere • Pioneer to climax • Let’s do NC Piedmont together!!! • Johnston and Odum pdf

20. Changes in Space and Time • Climax • Self-perpetuating community? • Dynamic equilibrium? • Examples • Spruce-fir, oak-hickory, tall grass prairie • Longleaf pine (disequilibrium) • Long-lasting communities • Loss of chestnut • Frasier fir and eastern hemlock to follow?

21. Changes in Space and Time Aquatic ecosystems • Oligotrophic • Geologically young, “few nutrients” • Eutrophic • A lot of nutrients • Succession is oligotrophic to eutrophic • Eutrophication • Sewage • Lake Erie • 1960-70’s “dead” • Phosphorus from detergents • Algae blooms, high BOD (biological oxygen demand), anoxia • In 1970’s- 80’s controlled nutrient inputs and anoxia levels decreases • In 90’s anoxic zones, dead zones, began to increase again, why? • Stratified longer due to global warming, so more BOD below thermocline?

22. Succession & Wildlife Mgt • Early successional species • “r” selected • Disturbance dependent environments • High reproductive potential • Short lived, rapid turnover • Good dispersers • Smaller size • Successional “threat” • Many, but not all, disturbance-dependent species doing well

23. Succession & Wildlife Mgt • Late successional species • “K” selected • Stable communities • Good competitors • Long lived, slow turnover • Low reproductive potential • Poor disperses • Larger size • Climax species -- tendency to not do well

24. Diversity r/K Strategies • Intermediate Disturbance Hypothesis • Too little, K-strategists dominate • Too much, r-strategists dominate • Intermediate disturbance frequency yields maximum species diversity

25. Succession & Wildlife Mgt • Disturbance communities are more abundant than climax communities

26. Diversity and Stability • Species diversity • S = Number of species = species richness • Abundance • N = population size • Density = N/unit area = N/A • Latitudinal gradient in species diversity • Tropics - high S, low number of individuals per species • Poles - vise versa

27. Diversity/Stability • How to measure diversity? • S = species richness • Shannon-Weaver Index (H’) • Includes numbers of individuals per species • Evenness (equitability), equal number of individuals per species • Higher S, higher H’ • more evenness, higher H’ • H’max = lnS • All kinds of diversity • Genetic, individual, species, community, etc • Trying to resolve diversity into a single number is problematic

29. 5 species, unevenness Same as above, but 10x more numbers H’ is the same 10 species, unevenness; same number of individuals as the top example; H’ greater Same as above but even; H’ greater

30. Diversity/Stability Text definition of stability Relative consistency in the abundance of populations • There is no such thing. • Text definition is overly simplistic

31. Diversity/Stability • Equilibrium stability • Returns to original state after perturbation • No perturbation, no change • Resilience • Short time to return to original state after perturbation • Rapid recoil • Tundra vs. pine woods • Resistance • How much perturbation is needed to effect change? • A little, unstable • A lot, stable

32. Diversity/Stability • Early ecologists • Greater diversity = stability • Intuitive appeal, but data to support?

33. Diversity/Stability • Now • W/in ecosystem diversity and stability tend to be positively correlated • Diversity is not a driver, but a consequence • It’s not a mechanism (interactions, processes) • What is the mechanism? • Interactions among species? • Weak, then more independent, and more stable • Strong, then more dependent, and less stable • Differential response of species or guilds (functional groups) to varying conditions

34. Diversity/Stability • Symbiosis • General term for the relationship between dissimilar organisms • Specific types • Mutualism -- both benefit • Lichens -- fungus and algae • Obligatory vs. facultative • Commensalism -- one benefits, other not harmed -- mussels? • Parasitism -- one benefits, other harmed

35. Diversity/Stability Example of mutualism??? • Calvaria forests on Mauritius and the dodo • Calvaria major (Dodo tree) (old scientific name) • Tambalacoque (Sideroxylon grandiflorum)

36. Diversity/Stability • Pollution tends to simplify communities • EPT index • The abundance of macroinvertebrates in streams • orders Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies) • Sum of the number of Ephemeroptera, Plecoptera, and Trichoptera divided by the total number of midges (Diptera: Chironomidae)

37. Diversity/Stability • Monocultures • Agriculture • Forestry • Maintaining biodiversity is a good thing • “To keep every cog and wheel is the first precaution of intelligent tinkering” Leopold • Society for Conservation Biology (SCB) • To advance the science and practice of conserving the Earth's biological diversity.

38. Diversity/Stability Debate • Why important? • Great loss in species diversity • Great increase in invasive exotics • Implicit assumption that ecosystems evolved the ability to withstand these assaults • Will this destabilize ecosystems?