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News Guns in National Parks GSMNP Python bounty hunters Ecosystems Ecology -- Interactions between living and nonliving elements that sustain life Biotic community Ecosystem Affected by external/internal factors Perturbations Fire, hurricanes, insects, over grazing, timbering Anthropogenic or “natural” All recovering from some past disturbance Living parts of an ecosystem Nothing is constant except change Everything is connected to everything else Limits difficult to define 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 Ecosystems Scale Large Smaller Longleaf pine forest Regenerating stand Smaller still Biosphere Biome Single tree Boundaries difficult to define Ecosystems Self sustaining? Entropy Second Law of Thermodynamics Entropy is a measure of disorder (and order) Entropy tends to increase over time 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 Ecosystems Cities don’t qualify as ecosystems? Not self-sustaining? But ecosystems couldn’t be sustained either w/o a lot of energy input Because they import a lot of energy Raw materials transformed but little replenished 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? Manipulate Ecosystems Wildlife management intentionally manipulates communities and ecosystems (to achieve a goal) That’s why the chapter seems to focus on disturbance Matter and Energy Carbon based Photosynthesis Organic chemistry CO2 + H20 = sugars + O2 Galapagos Rift Volcanic hydrothermal vents Sulfur-based life Chemoautotrophic bacteria Hyperthermophiles SLMEs Subsurface lithoautotrophic microbial ecosystems Food (Chains) Webs All require energy and matter Trophic levels Primary producers - autotrophs Plants Consumers Primary consumers Secondary Carnivore Tertiary Herbivores Top level carnivores Decomposers 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 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 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? Range of Tolerance (Ecological Amplitude) Temperature, moisture, heat, salinity,… Halophytes Steno -- narrow Stenophagus -- Everglades Stenoky -- RCW Eury -- wide Eurythermal Euroky Euryphagus -- wild pigs kite 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 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. 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) Niche Animal’s “profession” Habitat “address” Multidimensional hyperspace Generalists vs. specialists Spruce grouse -- winter diet jack pine needles Ruffed grouse -- aspen catkins Ecological equivalent Euroky vs. stenoky Sympatric species Climatograph 2 dimensions (temp, rain) Capercaillie -- Scot’s pine in Europe Robin vs. Woodcock 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 Out cats compete native species Examples? Changes in Space and Time Spatial Biomes -- climate determined Temporal Succession Primary vs. secondary Successional sere Dominant plants Grassland, deciduous forest Pioneer to climax Let’s do NC Piedmont together!!! Johnston and Odum pdf Changes in Space and Time Climax Examples Self-perpetuating community? Dynamic equilibrium? Spruce-fir, oak-hickory, tall grass prairie Longleaf pine (disequilibrium) Long-lasting communities Loss of chestnut Frasier fir and eastern hemlock to follow? 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? 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, disturbancedependent species doing well 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 Diversity r/K Strategies Intermediate Disturbance Hypothesis Too little, K-strategists dominate Too much, r-strategists dominate Intermediate disturbance frequency yields maximum species diversity Succession & Wildlife Mgt Disturbance communities are more abundant than climax communities Diversity and Stability Species diversity Abundance S = Number of species = species richness 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 Diversity/Stability How to measure diversity? S = species richness Shannon-Weaver Index (H’) All kinds of diversity 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 Genetic, individual, species, community, etc Trying to resolve diversity into a single number is problematic Spe cie s n p A B C D 30 20 40 10 0.3 0.2 0.4 0.1 -1.204 -1.609 -0.916 -2.303 ln p -0.361 -0.322 -0.367 -0.230 pl np 10 0 1 H'= -1.280 Spe cie s n p ln p pl np A 25 0.25 -1.386 -0.347 B C D 25 25 25 0.25 0.25 0.25 -1.386 -1.386 -1.386 -0.347 -0.347 -0.347 10 0 1 H'= -1.386 H'= S= ln S = Hma x= J=H'/Hma x 1.280 4 1.386 0.923 H'= 1.386 sp eci es a b c d e N 15 20 10 40 15 10 0 p 0.15 0.2 0.1 0.4 0.15 ln p -1.8971 2 -1.6094 379 -2.3025 851 -0.9162 907 -1.8971 2 pl np -0.2845 68 -0.3218 876 -0.2302 585 -0.3665 163 -0.2845 68 -1.4877 984 a b c d e 15 0 20 0 10 0 40 0 15 0 10 00 0.15 0.2 0.1 0.4 0.15 -1.8971 2 -1.6094 379 -2.3025 851 -0.9162 907 -1.8971 2 -0.2845 68 -0.3218 876 -0.2302 585 -0.3665 163 -0.2845 68 -1.4877 984 a b c d e f g h I j 20 7 5 5 8 30 5 10 8 2 10 0 0.2 0.07 0.05 0.05 0.08 0.3 0.05 0.1 0.08 0.02 -1.6094 379 -2.6592 6 -2.9957 323 -2.9957 323 -2.5257 286 -1.2039 728 -2.9957 323 -2.3025 851 -2.5257 286 -3.9120 23 -0.3218 876 -0.1861 482 -0.1497 866 -0.1497 866 -0.2020 583 -0.3611 918 -0.1497 866 -0.2302 585 -0.2020 583 -0.0782 405 -2.0312 03 a b c d e f g h I j 10 10 10 10 10 10 10 10 10 10 10 0 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 -2.3025 851 -2.3025 851 -2.3025 851 -2.3025 851 -2.3025 851 -2.3025 851 -2.3025 851 -2.3025 851 -2.3025 851 -2.3025 851 -0.2302 585 -0.2302 585 -0.2302 585 -0.2302 585 -0.2302 585 -0.2302 585 -0.2302 585 -0.2302 585 -0.2302 585 -0.2302 585 -2.3025 851 H' 5 species, unevenness -1.4877 984 -1.4877 984 -2.0312 03 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 -2.3025 851 Diversity/Stability Text definition of stability Relative consistency in the abundance of populations There is no such thing. Text definition is overly simplistic Diversity/Stability Equilibrium stability Resilience Returns to original state after perturbation No perturbation, no change 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 Diversity/Stability Early ecologists Greater diversity = stability Intuitive appeal, but data to support? 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 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 Diversity/Stability Example of mutualism??? Calvaria forests on Mauritius and the dodo Calvaria major (Dodo tree) (old scientific name) Tambalacoque (Sideroxylon grandiflorum) 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) Diversity/Stability Monocultures Maintaining biodiversity is a good thing Agriculture Forestry “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. Diversity/Stability Debate Why important? Great Great loss in species diversity increase in invasive exotics Implicit assumption that ecosystems evolved the ability to withstand these assaults Will this destabilize ecosystems?