Biol 302 succession 1 COMMUNITY CHANGE (SUCCESSION) Krebs cpt. 21; pages ; 431

Biol 302 succession 2 SUCCESSION …. Is the non-seasonal, directional and continuous pattern of colonization and extinction on a site by populations. Is the replacement of one kind of community by another kind; the progressive changes in vegetation and animal life that may culminate in the climax community (Krebs 622)

Biol 302 succession 3 PRIMARY SUCCESSION …. … recovery from a new sterile area that has been uncovered by a retreating glacier, or created by an erupting volcano. SECONDARY SUCCESSION …. … recovery of a disturbed site.

Biol 302 succession 4 PRIMARY SUCCESSION Mt. St. Helens pp Lake Michigan dunes pp Glacier Bay pp

Biol 302 succession 5 Krebs Fig. 21.7; p414 Ice recession in Glacier Bay, Alaska, since

Biol 302 succession 6 SECONDARY SUCCESSION Krebs pp

Biol 302 succession 7 From Drury and Nisbet 1973 “Succession can be considered as an expression of differences in colonizing ability, growth and survival of organisms adapted to a particular set of conditions on an environmental gradient.” “The replacement of one of several species or groups of species by others results from interspecific competition and the interactions of herbivores, predators, and disease which permit one group plants to suppress slower-growing or less tolerant ones.”

Biol 302 succession 8 1. OBLIGATORY SUCCESSION SUCCESSION PATHWAYS (HENRY HORN) ABCD

Biol 302 succession 9 1.OBLIGATORY SUCCESSION 2.CHRONIC, PATCHY DISTURBANCE AB C D

Biol 302 succession 10 1.OBLIGATORY SUCCESSION 2.CHRONIC, PATCHY DISTURBANCE 3.COMPETITIVE HIERARCHY ABCD

Biol 302 succession 11 1.OBLIGATORY SUCCESSION 2.CHRONIC, PATCHY DISTURBANCE 3.COMPETITIVE HIERARCHY 4.QUASI-REALITY

Biol 302 succession 12 Institute Woods, Princeton, N.J. (Henry Horn) Eastern deciduous hardwood forests

Biol 302 succession 13 Grey Birch, Betula populifera Black Gum, Nyssa sylvatica

Biol 302 succession 14 Red Maple, Acer rubrum Beech, Fagus sylvatica

Biol 302 succession QUASI-REALITY GRAY BIRCH BLACK GUM RED MAPLE BEECH

Biol 302 succession QUASI-REALITY GRAY BIRCH BLACK GUM RED MAPLE BEECH GRAY BIRCH BLACK GUM RED MAPLE BEECH

Biol 302 succession QUASI-REALITY GRAY BIRCH BLACK GUM RED MAPLE BEECH

Biol 302 succession 18

Biol 302 succession 19 No. of individuals IN 50 YEARS GRAY BIRCH BLACK GUM RED MAPLE BEECH No. of individuals NOW GRAY BIRCH BLACK GUM RED MAPLE BEECH-1396 Values in cells are percentages, and represent the probability (% probability) that any particular individual tree living now will be replaced by any other individual tree 50 years from now. e.g. out of every 100 individuals of grey birch now living, in 50 years, 36 of those grey birch will have died and will have been replaced by black gum.

Biol 302 succession 20 FOR EXAMPLE: The number of Red Maple and 50 years will be: 50% Gray Birch (now) 25% Black Gum (now) 55% Red Maple (now) 3% Beech (now)

Biol 302 succession 21 The predicted percentage composition of a forest consisting initially of 100% Grey Birch. Age of forest (yrs) Now  Data from old forest GRAY BIRCH BLACK GUM RED MAPLE BEECH

Biol 302 succession 22 From Connell and Slatyer 1977  FACILITATION  TOLERANCE (COMPETITION)  INHIBITION

Biol 302 succession 23 FACILITATION …later stages depend upon early-stage species to prepare a favorable environment for them

Biol 302 succession 24 TOLERANCE…later successional species tolerate lower resource levels [i.e. have lower R*] than earlier occupants, and can invade and displace them by reducing resources to levels below those tolerated by earlier occupants

Biol 302 succession 25 TOLERANCE…later successional species tolerate lower resource levels [i.e. have lower R*] than earlier occupants, and can invade and displace them by reducing resources to levels below those tolerated by earlier occupants i.e. the community is composed of those species most efficient at exploiting resources

Biol 302 succession 26 INHIBITION…all species resist the invasion of competitors and are displaced only by death, or damage by factors other than competition.

Biol 302 succession 27 INHIBITION…all species resist the invasion of competitors and are displaced only by death, or damage by factors other than competition. i.e. colonizers will hold a side against all comers until death

Biol 302 succession 28

Biol 302 succession 29 FACILITATION TOLERANCE INHIBITION

Biol 302 succession 30 A study from abandoned farmland illustrates some aspects of Facilitation, Tolerance and Inhibition (see Krebs pp ) FIELD ABANDONED IN FALL 1. INITIAL INVASION: Horseweed Horseweed a winter annual a winter annual produces abundant seed produces abundant seed self-allelopathic self-allelopathic Conyza canadensis

Biol 302 succession NEXT SEASON: AstersAsters More susceptible to decaying roots of horseweed, than horseweedMore susceptible to decaying roots of horseweed, than horseweed Tolerant of dry conditionsTolerant of dry conditions

Biol 302 succession SECOND AND THIRD SEASONS 3. SECOND AND THIRD SEASONS: BluestemBluestem Seedlings invading since initial abandonmentSeedlings invading since initial abandonment BroomsedgeBroomsedge Seedlings invading since initial abandonmentSeedlings invading since initial abandonment More tolerant of dry conditions than AstersMore tolerant of dry conditions than Asters Decaying roots of Horseweed promote growthDecaying roots of Horseweed promote growth

Biol 302 succession 33 Bluestem Broomsedge

Biol 302 succession 34 FACILITATION: Broomsedge promoted by decaying root TOLERANCE: Broomsedge displaces Aster through competition for water INHIBITION: Horseweed seedlings more tolerant of horseweed decomposition than Asters SUMMARY

Biol 302 succession 35 THE RESOURCE RATIO HYPOTHESIS OF PLANT SUCCESSION David TILMAN

Biol 302 succession 36 TILMAN, D The resource-ratio hypothesis of plant succession. American Naturalist 125: READING FOR THESE LECTURES: Krebs: selections from pp

Biol 302 succession 37 Resource Ratio Hypothesis One species and one resource One species and two resource Two species and two resources Multiple species and two resources

Biol 302 succession 38 Resource Ratio Hypothesis One species and one resource One species and two resource Two species and two resources Multiple species and two resources

Biol 302 succession 39 Resource Ratio Hypothesis One species and one resource One species and two resource Two species and two resources Multiple species and two resources

Biol 302 succession 40 Resource Ratio Hypothesis One species and one resource One species and two resource Two species and two resources Multiple species and two resources

Biol 302 succession 41 Resource Ratio Hypothesis One species and one resource One species and two resource Two species and two resources Multiple species and two resources

Biol 302 succession Resource level [1] Population growth [death] rate mortality Species A birth R*

Biol 302 succession 43 OPTIMAL FORAGING Any (plant) species will absorb resources in the proportion by which it is equally limited by them. This proportion is the ratio of the two values of R* R* = the Requirement Value i.e. the level of resource required to hold a population (of a species) at equilibrium: i.e. where birth rate = death rate

Biol 302 succession 44 OPTIMAL FORAGING Any (plant) species will absorb resources in the proportion by which it is equally limited by them. This proportion is the ratio of the two values of R* R* = the Requirement Value i.e. the level of resource required to hold a population (of a species) at equilibrium: i.e. where birth rate = death rate

Biol 302 succession 45 OPTIMAL FORAGING Any (plant) species will absorb resources in the proportion by which it is equally limited by them. This proportion is the ratio of the two values of R* R* = the Requirement Value i.e. the level of resource required to hold a population (of a species) at equilibrium: i.e. where birth rate = death rate

Biol 302 succession Resource level [2] Population growth [death] rate mortality Species A birth R*

Biol 302 succession Resource level [1] Population growth [death] rate mortality Species B birth R*

Biol 302 succession Resource level [2] Population growth [death] rate mortality Species B birth R*

Biol 302 succession 49 Population growth [death] rate SPECIES A SPECIES B Resource 1Resource

Biol 302 succession 50 Resource Ratio Hypothesis One species and one resource One species and two resource Two species and two resources Multiple species and two resources

Biol 302 succession Species A Resource [2] Resource [1] Births [A] > Deaths [A] Population increases Births [A] < Deaths [A] Population declines Zero Net Growth Isocline [ZNGI]: Births = Deaths

Biol 302 succession Species B Resource [2] Resource [1] Births [B] > Deaths [B] Population increases Births [B] < Deaths [B] Population declines Zero Net Growth Isocline [ZNGI]: Births = Deaths

Biol 302 succession 53 Resource Ratio Hypothesis One species and one resource One species and two resource Two species and two resources Multiple species and two resources

Biol 302 succession Species A and B Resource [2] Resource [1] ZNGI [A] ZNGI [B]

Biol 302 succession A Resource [2] Resource [1] ZNGI [A] ZNGI [B] B

Biol 302 succession A B Resource [2] Resource [1] ZNGI [A] ZNGI [B] Neither species can survive A wins B wins Both species can grow

Biol 302 succession A B Resource [2] Resource [1] ZNGI [A] ZNGI [B]

Biol 302 succession A B Resource [2] Resource [1] ZNGI [A] ZNGI [B] Neither species can survive A wins B wins A & B coexist

Biol 302 succession A B Resource [2] Resource [1] ZNGI [A] ZNGI [B] Neither species can survive A wins B wins A & B coexist WHY?

Biol 302 succession A B Resource [2] Resource [1] ZNGI [A] ZNGI [B]

Biol 302 succession A B Resource [2] Resource [1] ZNGI [A] ZNGI [B]

Biol 302 succession 62 Resource Ratio Hypothesis One species and one resource One species and two resource Two species and two resources Multiple species and two resources

Biol 302 succession A B C D E Resource [2] Resource [1] A B C D E

Biol 302 succession A B C D E Resource [2] Resource [1] A B C D E None AAB BC C CD D DE E B

Biol 302 succession A B C D E Resource [2] Resource [1] A B C D E None AAB BC C CD D DE E B Random Resource Supply

Biol 302 succession A B C D E Resource [2] Resource [1] A B C D E None AAB BC C CD D DE E B Positively Correlated Resources

Biol 302 succession A B C D E Resource [2] Resource [1] A B C D E None AAB BC C CD D DE E B Negatively Correlated Resources

Biol 302 succession A B C D E Resource [Light] Resource [Nitrogen] A B C D E A AB BC C CD D DE E B PRIMARY SUCCESSION

Biol 302 succession A B C D E Resource [Light] Resource [Nitrogen] A B C D E A AB BC C CD D DE E B SECONDARY SUCCESSION Poor soilRich soil

Biol 302 succession Resource [Light] Resource [Nitrogen] Aspen Black Oak & Aspen Black Oak Red Oak & Black Oak Red Oak White Oak & Red Oak White Oak Sugar Maple & White Oak Sugar Maple

Biol 302 succession A B C D E Resource [Light] Resource [Nitrogen] A B C D E DIVERSITY

Biol 302 succession 72 TILMAN THE END

Biol 302 succession 73 FORCIER, Keith Studied trees in a New Hampshire forest Trees with dbh <2 cm (400 plots) 90% of canopy: Sugar maple American beech Yellow birch

Biol 302 succession 74 SPECIES Density (#/m 2 ) (d min /d max ) x 100 % plots with at least 1 seedling Mass/ind (mg) Yellow birch Sugar maple Beech

Biol 302 succession 75 Number of cohort alive at beginning of interval Age interval Yellow birch Sugar maple Beech <

Biol 302 succession 76 CANOPYSEEDLINGSSAPLINGS < 0.5m tall0.5 – 2 m tall Yellow birch Sugar maple Beech Sugar maple Yellow birch Sugar maple Beech BeechYellow birch Sugar maple Beech Seed - Sprouts +

Biol 302 succession 77 CATASTROPHIC DISTURBANCE Yellow birch Sugar Maple Beech (seed) Beech (sprouts) MINOR DISTURBANCE Successional communities

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