Ecology Exam 5 PDF

 Chapter 18 : Primary Secondary Production + Introduction Ecosystem ecolo...

 Chapter 18 : Primary Secondary Production + Introduction Ecosystem ecologists study flows of energy water nutrients in ecosystems ·. , , Primary production : production of organic matter per unit area in ecosystem during · new some period of time. Gross total amount of all primary production primary production by : - primary producers. Net primary production gross primary production respiration ; the amount - : minus of biomass available to consumers. Secondary production : biomass production by during some period of time. · consumers Trophic Levels Trophic level : position in food web. · a Determined number of transfers from to by energy primary producers - Current level. Primary producers occupy first level. · Primary second level. · consumers occupy = Herbivores + detritivores. Secondary consumer occupy third level. · Carnivores feeding herbivores dentritivores = on , , Tertiary Consumers the fourth level · occupy. 18 1 Patterns Production. of Terrestrial Primary Terrestrial primary production is limited generally by : · 1) Temperature 2) Moisture 3) Nutrients Temperature and moisture correlated w/ primary production · are most highly. Highest rates occur under moist conditions · warm ,. Actual Evapotranspiration Terrestrial Primary Production + Rosenzweig (1968) estimated influence of moisture + temperature · rates of primary on production n.  plotted relationship b/w annual net primary production · + annual actual evapotranspiration (AET). · AET : annual amount of water that evaporates + transpires off a landscape. Cold dry ecosystems tend to have low AET -. , Primary Production in Central Grassland Sala et al (1988) studied factors controlling primary production in grasslands of ·. Central USA. Highest in east lowest in. - , west Correlated significantly w/ rainfall -. models from Rosenzweig + Sala did not completely explain variation in primary · productivityFertility + Terrestrial Primary Production Significant variation in terrestrial primary · production can be explained by differences in soil fertility. Shaver + Chapin /1986) arctic tundra net primary · - production nearly doubled on fertilized plots compared to unfertilized plots. Bowman et al (1993) found increased adding nutrients primary production dry wet ·. in meadows. N P in wet. limiting in dry meadow ; N + is - 18 2 Patterns of. Aquatic Primary Production · Aquatic primary production is generally limited by nutrient availability. · Patterns + models. Quantitative relationship blu phosphorus phytoplankton biomass · +. Nutrients , biomass in especially phosphorus controls phytoplankton - , freshwater ecosystems.  Whole-Lake Production Experiments on Primary · Experimental Lakes Area in Canada Lake divided into two · Sucrose nitrate added , to one basin. Phytoplankton biomass increased 2-4X · - · Carbon , nitrate , phosphorus to one basin. Phytoplankton biomass increased 4-8X. - Global Patterns of Marine Primary Production Highest rates of primary production by phytoplankton generally concentrated · marine are W/ levels of nutrient availability in areas higher - Highest rates along continental margins + in areas of upwelling. · - Nutrient run-off from land. - Sediment disturbance. Open ocean tends to be nutrient poor. · Vertical mixing is main nutrient source. · - Blocked in tropies by thermocline. Nutrient Enrichment in Black Sea Graneli et al (1990) gathered results suggesting rate of primary production in Baltic ·. Sea is nutrient limited - Increased nitrate led to increased concentrations ; increased chlorophyll · did phosphates not. Nitrogen to limiting nutrient , not phosphorus. appears be - 18 3 Primary Producer Diversity. · Primary producer diversity contributes to higher primary production. Physical chemical factors affect rates of primary production - +. Biological factors also influence rates. - Several aspects of biodiversity important to primary production + other ecological · are processes.  Terrestrial Plant Diversity + Primary Production · Tilman et al. (2001) examined plant functional groups plants , w/ similar physiological anatomical characteristics. + · Manipulated number of species + functional that were groups present in 168 plots. Plant species richness correlated w/ primary production. · N-fixing legume Cy grass functional groups had higher productivity. + · Biological influences can be just as important as chemical physical factors. · + Algal Diversity Agratic Primary Production + Primary producer diversity increases primary production in experimental aquatic · ecosystems (2011) found. - Cardinale increase in nitrate uptake + biomass w/ increasing algal species richness. These patterns be extrapolated to larger scales. · can P Study of 1 157 lakes in USA found of N availability + correlation - , algal diversity w/ primary production +. 18 4 Consumer Influences. Consumers terrestrial influence rates of primary production in aquatic + · can ecosystems through trophic cascades. Primary production affected by - is consumers. Bottom-up controls influences of physical : chemical · + factors on ecosystems. Top-down controls : influences of ecosystems. · consumers on Piscivores , Planktivores , Lake Primary Production · Carpenter et al. (1985) proposed piscivorous + planktivorous fish significant deviations in can cause primary productivity. Influence of consumers on lake primary productivity propagates · through food webs.  Trophic Cascade effects of predators alter than - more - on can prey one trophic level. Trophic cascades involve indirect interactions. - Lake Trophic Cascade · Carpenter + Kitchell (1993) - Reduction in planktivorous fish populations led to reduced feeding pressure on zooplankton. dominate Large-bodied Zooplankton soon -. Reduced phytoplankton biomass + rate of primary production. - Consistent w/ reported negative correlation b/w zooplankton body size + primary · production. Grazing by(1985) Large Mammals + Primary Production on the Serengeti McNaughton estimated Serengeti of 66 % · grazers consume an average of annual primary production. Rate of primary production in the Serengeti is positively correlated w/ rainfall quantity · Grazing can increase primary production ·. · Increases growth rate of many grasses. Compensatory growth. · Lower improved water respiration reduced self-shading balance. - , , Compensatory Growth found McNaughton compensatory growth highest at intermediate · intensities. grazing insufficient to produce Light grazing compensatory growth. - Heavygrazingreduces torec. plants capacity at Ecosystems w/greater primary production generally support higher levels of · secondary production. - W/ each energy transfer from one trophic level to another , some is lost.  Food /growth ingested is used for respiration excretion + production of biomass - , , reproduction) or secondary production +. , A Trophic Dynamic View of Ecosystems Lindeman (1942) concluded the ecosystem · concept fundamental of is to the study energy transfer within an ecosystemtrophic dynamics). Suggested grouping organisms within ecosystem into trophic levels. · an Each feeds immediately below level - on. - Ecological efficiency is the percentage of energy transferred from one trophic level to the one. above it · varies from about 5 % to 20 %. Results distribution of levels. pyramids-shaped energy among trophic · in Estimating Secondary Production Secondary production is key to understanding energy flow in ecosystems ·. Benke's approach to to follow estimating secondary production cohort over · was a time. of larvae Study dragonfly over 10 months. - Secondary production Often expressed unit time · biomass area unit as per per. Production Linking Primary Secondary Production + Predictions of secondary production depend the relationship b/w primary · + on which predator prey - model is used. The prey-dependent model predicts that increased primary production will - lead to an increase in secondary consumer (predators) abundance but no change in consumers Cherbivores) primary. The ratio-dependent model predicts that increased primary production will lead - to an increase in both primary secondary + consumers.  Enrichment Production Secondary + Evidence that increased fosters primary production greater secondary production · in terrestrial + aquatic ecosystems. Positive herbivore in African correlation b/w annual precipitation secondary production - + Savanna ecosystems. In detritus-based stream of detritivores w/ increased ecosystem production - rose , food (leaf litter). Applications : Using Stable Isotope Analysis to Study Feeding Habits Fundamental step in studying trophic relations is determining what organisms. eat · Can be difficult if feeding habits variable if food items difficult to identify · are or are. Stable isotope analysis help · can. Using Stable Isotopes to Identify Sources of Energy in a Salt Marsh main of in eastern North American salt Marsh is primary · source energy production by marsh alterniflora. grass Spartina Marsh also contains organic material from upland plants phytoplankton - +. · Peterson. et al. (1985) examined the ratios of stable isotopes of carbon , nitrogen , + sulfer ble the ratios differed in the 3 sources. energy The differing ratios allowed them to determine that the diet composition of - the filter-feeding mussel , Gerkensia demissa , was primarily Spartina + plankton.  Chapter 20 : Succession + Stability Introduction Succession : change in plant animal + microbial communities in an area following · , , disturbance or creation of new substrate. Primary succession : occurs newly exposed geological substrate - on. Secondary succession : occurs following disturbance that does not destroy soil - · Pioneer community first : organisms to colonize following disturbance. · a Climax community later community : that persists until disrupted by disturbance. · Clement and Gleason · Nature ofClimax community + of succession have been focus of research process · · Clements : succession driven by interactions blw species. Composition of climax community highly predictable -. · Gleason : communities are the result of independent species distributions along environmental gradients. - Not predictable 20 1. Community Changes During Succession Primary etSuccession at Glacier Bay ·. Reiners al (1971) studied changes in plant diversity during succession. ·. Studied a chronosequence of sites. - Plots appeared to increase in diversity over time e. - Buma et al (2019) found that there wasn't a consistent progression of species · actually ·. Diversity either stayed the same decreased initial species mattered, = or , Secondary Succession in Temperate Forests of the Piedmont Plateau is well described. Secondary succession · Oosting (1942) found woody plant species richness increases during succession. - - Johnston + Odum (1956) found increase in bird diversity paralleled the increase in woody plant diversity. Succession Intertidal Communities in Rocky Intertidal boulder stripped of is recolonized ecological succession · soon organisms -. - Green alga + barnacle arrive first later colonizers , include red algae species ·  Number of species increases w/ time -. · Succession time varies. Glacier 1 Bay 500 - - , years - Piedmont Plateau 150 years = - Intertidal boulder succession = 1 5. years Succession Communities in Stream Fisher et al (1982) studied rapid succession in Sycamore Creek Arizona ·. ,. Evaporation flows intermittent. equalsnearly precipitation generally low · - + Subject to flash floods followed by succession - ,. Observed rapid changes in diversity composition of algae invertebrates , · + + = Diatoms + algae recolonize first. = Most macroinvertebrate species survived the flood as aerial adults. 20 2 Ecosystem Changes During. Succession Ecosystem Changes at Glacier Bay · Chapin et al (1994) documented changes in ecosystem structure -. duringTotal soil succession. depth + depth of all major soil horizons show - from significant increase pioneer community to spruce stage. Soil organic content , nitrogen concentration also - moisture + , increased. Physical biological properties + systems are inseparable of -. Four Million Years of Ecosystem Change · Hawaiian Islands formed over hot spot on Pacific tectonic plate forming , island chain (millions of · varying greatly in age years) Hedin et al (2003) found variation in soil features across chronosequence ·.. Organic matter nitrogen + increased at first then decreased. = , Total phosphorous showed no pattern. - Progressively higher rates of nitrogen loss , + decreased phosphorous loss. -  Succession + Stream Ecosystem Properties Sycamore Creek. Arizona had rapid biomass increase · , following flooding , then slower rates. Algal invertebrate biomass + -. Gross primary production total ecosystem nitrogen retention + respiration · , , showed similar pattern. Succession changes in diversity + changes structure · causes species composition + , + function of ecosystem. 20 3 Mechanisms of Succession. · Clements emphasized role of facilitation as driver of ecological succession. · Connell + Slatyer proposed 3 alternative models of succession. - Facilitation - Tolerance - Inhibition - facilitation Facilitation Many species may attempt to colonize newly available space. model · : Only certain species will initially establish · , Colonizing pioneer species modify environment so it becomes less suitable for species · of later successional stages. Climax community occurs when resident species no longer facilitate colonization by · additional species · Tolerance Tolerance model initial of colonization not limited to pioneer species. : stages · Juveniles of species that dominate at climax be present throughout may succession. · Early successional species do not facilitate later successional species. · Later species enter conditions. system if they tolerate the environmental · Climax when the list of tolerant has been exausted. community species · occurs  Inhibition Inhibition model : any species Can colonize during early succession , · Early occupants modify the environment , making it less suitable for both late · early + successional species. Early arrivals inhibit later colonization. - Later successional species invade only if is opened by disturbance. - space up Succession ends wr long-lived , resistant species that to dominate · come · Successional Mechanisms in Rocky Intertidal zone · Sousa investigated mechanisms of succession of algae + barnacles in intertidal boulder fields. Found species had lower survivorship early successional - , were Vulnerable to herbivores. Supports the inhibition model -. · Turner (1983), however , found that recruitment of surfgrass, Phyllospadix scouleri , was dependent on its seeds hooking onto macroalgae. Middle successional algae facilitate surfgrass recruitment (obligate facilitation). - - Supports the facilitation model. Successional Mechanisms in Forests · Mechanisms in Old Field Succession. · Keever (1950) examined old-field secondary succession. - Both inhibition + facilitation present at the earliest successional stage. Pioneer species matter organic facilitating - increase , successional species early , which once established (inhibition) competitively exclude the pioneer species. Later successional species establish if successional species only early - can are displaced (inhibition). Later successional species stimulated the of the climax species (facilitation)· growth -  20 4. Community + Ecosystem Stability Stability : absence of change. · · Sometimes due to lack of disturbance. May also result from ; · Resistance : to maintain structure function ability + in face of potential - disturbance. · Resilience : ability to recover from disturbance. Lessons from the Park Grass Experiment Experiment to study effects of fertilizer on meadow Hertfordshire, hay · in England. - Continued for 150 years. Plant composition has montered community been 1862. · since - No new species have colonized. Community composition variability used as measure of stability -. Proportions of glass legumes other plants has + remained relatively - , , constant. Further of Park Grass Experiment Analysis · Dodd et al 1199st showed that. although community stability is present populations , of individual species can change substantially. resolution at which Stability depends an area is · on investigated.- At course resolution Park Grass community has remained stable - still a meadow community. At fine resolution at individual species abundance trends looking not stable. - - - Replicate Disturbance + Desert Stream Stability Valett et al (1994) studied interaction blu surface ·. + subsurface waters of Creek Sycamore.  · Looked at hydrological linkages blu waters that could increase nitrogen supply. upwelling have highest nitrate concentrations + highest algal - zones production. Rate of ecosystem recovery higher in upwelling · zones. Spatial relationships of in Creek is stable · zones. - Resistant to disturbance. Stability due to geomorphology. - Applications Ecological Succession Informing Ecological Restoration : Ecological restoration : process of restoring damaged ecosystems to acceptable · levels of biodiversity Physical structure functioning· , , Restoration ecology : focuses improving effectiveness of restoration by · on providing conceptual framework. Restoration has suggested been to be "essentially the manipulation of · succession in order to achieve some predetermined Goal" (Walker et al., 2009). Succession Concepts to Restoration Applying · Succession involves changes over decades centuries. + Ecological restoration is restricted to few decades. · years or a · Must accelerate process of succession. Broad range of physical , chemical biological factors influence · process. + , Some facilitate successional. ; some habitchange - Restoring Tropical Forest · Dias et al (2012) tested addition. of forest floor litter seeding of bauxite mining tailings +. Succession the tailings was promoted w/ faster - on plant growth greater leaf area increased plant , , species richness , higher seedling densities I. Shiels Walker (2003) added bird perches (tree branches) to landslides in Puerto Rico. · + Augmented deposition of bird-dispersed seeds -.  Increased diversity of seeds. - Restoring Logging Road Beds · Lloyd et al. (2013) compared abandoned roads to roads that reconstructed to restore the contours of the site. were original Recontouring accelerated restoration ·. Recontoured roads required 10 to reach point of = years restoration equal to 30 on an abandonebroad years. Plant diversity was different , but after 10 years soil structure recontoured roads · on was indistinguishable from undisturbed sites.  Chapter 22 : Geographic Ecology Introduction MacArthur defined the "Search for of plant+ animal geographic ecology patterns · as life that can be put on a map. The study of ecological structure + process at large geographic scales. · Vast breadth , but here focusing : · on Island biogeography. in - - Latitudinal patterns species richness. Influences of biodiversity large-scale regional historical + processes - on Richness. 22.1 Area , Isolation, + Species Arrhenius first developed quantitative relationship b/w area+ number of species. · A pioneer of geographic ecology. - - Worked on islands in Sweden. Worked at scales much smaller than geographic scale. = Island Area + Species Richness · Preston looked at relationship b/w species number t West Indies Island area. Fewest bird species live - on smallest islands ; most species island. on largest Nilsson et al found island in Sweden was best single predictor ·. area of species richness among woody plants , carabid beetles , + land snails. Habitat Patches on Continents : Mountain Islands · Climate warmed at end of Pleistocene , forest + alpine habitats contracted to tops of high mountains across American Southwest. - Once forest contracted to series of island-like fragments associated continuous w/ mountains (montane vegetation). Montane animal distributions also contracted , we species richness - correlated w/ montane island area.  Lakes as Islands · Lakes can be considered habitat islands. · Lakes can be considered habitat islands. · Tonn + Magnuson studied Wisconsin lakes. Found the number of species increases w/ the area of the lake. - · Barbour + Brown used 70 lakes from around world. Also found - relationship b/w area + fish species richness. positive Marine Islands · MacArthur Wilson found isolation. + reduces bird diversity on Pacific Islands. · Williamson studied island area + species richness in Azure Channel Islands· + Birds + peridophytes have increased diversity w/ increasing island · area , Bird diversity is influenced by isolation , peridophyte diversity is not ·. Reflects differences in dispersal abilities Opteridophytes produce light spores) -. Isolation + Habitat Islands on Continents · Lomolino et al. looked at montane mammal species on mountaintops across American Southwest. Found strong negative relationship btw isolation Species number - +. Suggests that immigration is important in maintaining diversity. = 22.2 Equilibrium Model of Island Biography MacArthur + Wilson explained patterns of species · diversity on islands as result of balance of immigration + extinction rates. Equalibrium model of island biogeography. - · Rates of immigration would be highest new island on w/ no organisms. As species accumulate rate of declines since fewer arrivals immigration - , are new species.  Equilibrium Model - Extinction Rate of extinction would with number of species island rise increasing · on an for three reasons : - Presence of species creates a larger pool of potential extinctions. more As number of species increases , Size of each must diminish pop -.. As number of species increases , potential for competitive interactions blu - species will increase. Equilibrium Species Number Model + · Point where two lines cross predicts the number of species that will occur on an island. Rate of immigration mainly determined by distance from source of immigrants. · Rate of extinction determined mainly by island size ·. Large near islands support highest number. - - Small far islands support lowest number. Small near t large far support intermediate numbers. - Species Turnover on Islands · Equilibrium model predicts species composition on islands is dynamic. referred to Change as Species turnover -. · Diamond found birds in nine Calif Channel Islands in. a stable equilibrium. Due to number of immigrations extinctions. approximately equal + - Species turnover occurred. - Experimental Island Biogeography · Simberloff + Wilson studied insect recolonization in Florida keys. 2 mangrove islands controls. - as -6 defarnated. mangrove islands were Tracked recolonization for 1 - year. · On controls , species number was constant , but composition changed. Defaunated islands returned nearly · to original species numbers , but composition changed.  Colonization of New Islands by Plants · Rydin + Borgegard found variation in species richness correlated positively wr island area. - Explained 44 to 85 % of species richness variation among islands. · small + medium islands continued to accumulate species. islands attained Large equilibrium. = Difficult to effects of habitat diversity from effects. · separate area Island Manipulating Area · Simberloff tested effect of island area on species richness in mangrove islands. · In all cases where area was reduced , species richness decreased. - Richness on control island increased slightly. · Islands w/ reduced area lost species wr each reduction in area. showed positive influence has richness - area on species. Island Biogeography Update Kodrie-Brown Brown rates to near islands found higher immigration · + can reduce extinction rates. - Distance from colonist sources influences extinction rates. · Lomolino found island significant effect area can have a on immigration rates. Area + isolation of several environmental factors affect island only two · are richness. species 22 3. Latitudinal Gradients in Species Richness · Species richness generally increases from middle + high latitudes to the equator. Latitudinal Gradient Hypotheses ·. - Pattern of increased number of species in the tropics is persuasive + dramatic. Mechanism have Many been proposed -.  (1988) grouped Brown hypotheses into - six categories. 1 Time Since Perturbation. More species in thetropics ble tropics are older I disturbed less frequently ·. · There has been more time for speciation. · Less frequent disturbance reduces extinction rate. Assumes tropics have remained relatively Stable. · Middle-high latitudes have been disrupted by glaciation ·. Conversely Connell (1978) proposed tropical diversity is maintained by · , disturbance. 2. Productivity High productivity contributes to high species richness. · More to divide among populations · energy. · Specialized consumers will have lower chance of extinction. · Extinction rates should be lower.. Environment 3 Heterogeneity · Tropics have more species b/c they are more heterogeneous. Although most tropical species occur in fewer environments than high latitude · species. However, diversity habitat heterogeneity independent. + not species · are · Species in more diverse communities tend to subdivide environment more finely.. Favorableness 4 · Tropics provide more favorable environments. environments have High latitude more temperature variation -. Physically extreme environments restrict diversity -. 5. Niche Breadths + Interspecific Interactions Several hypotheses concerning relative niche breadths + interspecific · interactions , such ass  Tropical species limited more by biological factors than physical factors -. Tropical Species more subject to controls by predators pathogens - + , , parasites. Brown suggests biological processes must play secondary role ; ultimate · causes must be physical differences blu tropics higher latitudes. + 6 Differences in Speciation Extinction Rates +. · Number of in area reflects the rate at which species have been species new added minus rate at which they have disappeared. · Species added by speciation or immigration. discounted Rosenzweig proposed immigration can be at large scales. - Species removed by extinction ·. have more ble rates of and /or Tropics species they have higher speciation · lower rates of extinction. Area + Latitudinal Gradients in Species Richness Terborgh Rosenzweig proposed greater tropical · species richness explained by greater area. Not obvious if Mercator using projection ·. · More land ( water) + more uniform temperatures, so organisms can disperse widely I not experience significant changes. · Should reduce extinction rates. Larger species ranges should increase allopatric species rates ·. Continential Area Species Richness + · Flessa + Brown each found positive relationship blu continental + richness area species. Rosenzweig found similar relationship in tropical regions ·. 22 4 Historical. + Regional Influences Long-term historical t regional processes significantly · can influence species richness + diversity.  Exceptional Patterns of Diversity · - There are differences in species richness that cannot be explained by area. Cape region of South Africa is smaller than California Floristic Province , has yet - more species · More Exceptional Patterns · Latham + Ricklefs (1993) studied temperate zone trees. - Temperate forest biomes in Europe Eastern Asia , , + Eastern North America all have roughly equal area but , different levels of biological diversity vastly. · Ralph11985) found negative correlation b/w foliage height diversity bird species diversity Argentina + in. Historical + Regional Influences · The Cape Floristic Region of South Africa. Bond Goldblatt richness to several attributed unusually high species · + historic factors. geographic + Continental drift. - Wide variety of soil types -. Repeated expansion contraction + isolation of plant populations -. , , reduced extinction Refuge areas rates -. Diversity of Temperate Trees Must examine conditions trees in these regions faced during the last glacial · period. · Mountains in Europe form east-west oriented barriers. During last ice age temperate trees had southward retreat largely cut-off. - , Lower species richness of consequence higher extinction rate. · as Temperate Trees in Asia + North America Appalachian Mountains in N A North-South thus temperate trees had ·.. run , an avenue of retreat as temperatures became colder. · No mountain barriers in Asia.  Concluded from various lines of evidence that most temperate tree taxa originated · in Eastern Asia I dispersed to Europe N A +.. After dispersal routes were cut speciation continued in Asia - ,. Bird Diversity in the Beach Forests of S A.. Structurally complex beech forests of S A support lower bird diversity than ·.. shrub habitat. simpler due to restricted distribution of beech forests May be -. Beech forests isolated arid semiarid are by vegetation - +. Applications : Global Positioning Systems , Remote Sensing , Geographic Information Systems Modern tools have revolutionized geographic ecology. · Data often recorded geographic information systems. - on Geographic ecologists have to accurate data through remote - access more sensing global positioning systems +. Global Positioning Systems Identifying location is a basic task for a · geographer. (GPS) determines locations Earth's surface A global positioning system on -. - Uses satellites as reference points. Candetermine latitude , w/ longitude altitude+ great - accuracy ,. Remote Sensing Remote refers to about object who direct sensing gathering information · an contact wr it. radiation emitted reflected Mainly through electromagnetic by Object. - or Satellite-based remote detailed of Earth's surface. sensing produces · images · used to moniter biomass of vegetation. Mountain Islands in the American Southwest Satellites level of gathering information atover resolution be useful ·