Disturbance & Succession Satellite image taken Aug. 29, 2005 Change in Communities Disturbance & Succession “If you live in Louisiana, there are only two possibilities: either your land will eventually flood, or it will eventually burn.” Keddy (2008) Water, Earth, Fire: Louisiana’s Natural Heritage Please do not use the images in these PowerPoint slides without permission. Hurricane Katrina Satellite image taken Aug. 29, 2005 Image from http://earthobservatory.nasa.gov/Newsroom/NewImages/Images/katrina_goe_2005241_lrg.jpg

Change in Communities Disturbance & Succession Please do not use the images in these PowerPoint slides without permission. Indonesian island. Wikipedia “Krakatoa” page; accessed 29-X-2014. Anak Krakatau (emerged from the sea as new volcanic island in 1927) Satellite image taken June 11, 2005 Image taken by Ikonos satellite from Wikimedia Commons

Change in Communities Disturbance & Succession Please do not use the images in these PowerPoint slides without permission. Feral hog disturbance to seepage bog at Eglin Air Force Base, FL Photo taken October 25, 2014 K. Harms’s photo

Succession, Disturbance & Stress Succession – directional change in community composition at a site (as opposed to simple fluctuations), initiated by natural or anthropogenic disturbance, or the creation of a new site Some biologists restrict the definition to directional replacement of species after disturbance Disturbance – a discrete event that damages or kills residents on a site (and potentially creates opportunities for other individuals to grow or reproduce); either catastrophic or non-catastrophic (Platt & Connell 2003 Ecological Monographs) Please do not use the images in these PowerPoint slides without permission. Platt, William J. & Joseph H. Connell. 2003. Natural disturbances and directional replacement of species. Ecological Monographs 73:507-522. Stress – abiotic factor that reduces growth, reproduction, or survival of individuals (and potentially creates opportunities for other individuals)

Disturbance Catastrophic disturbance – a disturbance that kills all residents of all species on a site; i.e., creates a “blank slate” (Platt & Connell 2003 Ecological Monographs) Please do not use the images in these PowerPoint slides without permission. Platt, William J. & Joseph H. Connell. 2003. Natural disturbances and directional replacement of species. Ecological Monographs 73:507-522. Mt. St. Helens, Washington, U.S.A. May 18, 1980 Photo of Mt. St. Helens from Wikimedia Commons

Disturbance Non-catastrophic disturbance – a disturbance that falls short of wiping out all organisms from a site; i.e., leaves “residual organisms” or “biological legacies” (Platt & Connell 2003 Ecological Monographs) Please do not use the images in these PowerPoint slides without permission. Platt, William J. & Joseph H. Connell. 2003. Natural disturbances and directional replacement of species. Ecological Monographs 73:507-522. Yellowstone Nat’l. Park, U.S.A. just after 1988 fires Luquillo Experimental Forest, Puerto Rico just after 1989 Hurricane Hugo Photo of Yellowstone in 1988 from Wikimedia Commons; Photo of Luquillo Forest, Puerto Rico in 1989 from http://pr.water.usgs.gov/public/webb/hurricane_hugo.html

Intensity, Frequency & Extent Disturbance Intensity, Frequency & Extent Please do not use the images in these PowerPoint slides without permission. Bowman, Hacker & Cain (2017), Fig. 17.4

Disturbance & Succession Primary Succession – succession that occurs after the creation of a “blank slate,” either through catastrophic disturbance or de novo creation of a new site Please do not use the images in these PowerPoint slides without permission. Mt. St. Helens, Washington, U.S.A. May 18, 1980 Anak Krakatau, Indonesia appeared above water 1927 Photo of Mt. St. Helens in 1980 from Wikimedia Commons; Photo of Anak Krakatau from http://amazingindonesia.net/2008/06/mount-krakatoa-the-wrath-of-earth

Disturbance & Succession Secondary Succession – succession that occurs after non-catastrophic disturbance (including “old fields”) Please do not use the images in these PowerPoint slides without permission. Yellowstone Nat’l. Park, U.S.A. just after 1988 fires Luquillo Experimental Forest, Puerto Rico just after 1989 Hurricane Hugo Photo of Yellowstone in 1988 from Wikimedia Commons; Photo of Luquillo Forest, Puero Rico in 1989 from http://pr.water.usgs.gov/public/webb/hurricane_hugo.html

Disturbance Bowman, Hacker & Cain (2017), Fig. 17.5 Please do not use the images in these PowerPoint slides without permission. Bowman, Hacker & Cain (2017), Fig. 17.5

Disturbance & Succession Henry Chandler Cowles Lake Michigan sand dunes – late 1800s Concluded that sites on the dunes were older further inland, i.e., formed a “chronosequence” from which temporal change could be inferred (space-for-time substitution) Please do not use the images in these PowerPoint slides without permission. Photo of Cowles from http://oz.plymouth.edu/~lts/ecology/ecohistory/cowles.html; photo of Lake Michigan sand dune from http://ebeltz.net/folio/cfol-5.html

Disturbance & Succession Frederick Clements Radical, “superorganism” view of communities; species interact to promote a directed pattern of community development through “seral” stages, ending in a “climax” community Henry Gleason “individualistic view of succession” in which “every species is a law unto itself” Please do not use the images in these PowerPoint slides without permission. See Sharon Kingsland’s book… Our modern population-biology view derives primarily from Gleason’s conceptual model, even though Clementsian ideas of deterministic progression through seral to climax stages dominated ecological theory well into the 20th century Photos from http://oz.plymouth.edu/~lts/ecology/ecohistory/history.html

Disturbance & Succession Three Models of Succession Connell & Slatyer (1977) The American Naturalist 1. Facilitation – Early-colonizing species modify the environment and enhance the establishment of later-arriving species (perhaps most likely in primary succession) 2. Tolerance – Early-colonizing species modify the environment, but have no effect on later-arriving species 3. Inhibition – Early-colonizing species modify the environment in ways that actively inhibit later-arriving species Please do not use the images in these PowerPoint slides without permission. Connell, J. H. & R. O. Slatyer. 1977. Mechanisms of succession in natural communities and their role in community stability and organization. The American Naturalist 111:1119-1144.

Disturbance & Succession Primary succession along the Glacier Bay chronosequence One of the world’s most rapid and extensive glacial retreats in modern times (so far); eliminated ~2500 km2 of ice in ~200 yr, exposing large expanses of nutrient-poor boulder till to biotic colonization Please do not use the images in these PowerPoint slides without permission. Photo of Glacier Bay National Park, Alaska from Wikimedia Commons

Disturbance & Succession Primary succession along the Glacier Bay chronosequence Reconstructed patterns of stand development at several sites within the chronosequence; intensively analyzed tree-rings Please do not use the images in these PowerPoint slides without permission. Fastie, Christopher L. 1995. Causes and ecosystem consequences of multiple pathways of primary succession at Glacier Bay, Alaska. Ecology 76:1899-1916. Bowman, Hacker & Cain (2017), Fig. 17.9, after Chapin et al. (1994) Ecol. Monogr. and Fastie (1995) Ecology

Disturbance & Succession Primary succession along the Glacier Bay chronosequence Species richness generally increased with successional age Please do not use the images in these PowerPoint slides without permission. Pioneer stage = lichens, mosses, horsetails, willows & cottonwoods. Dryas drummondii = small shrub. Reiners, W. A., I. A. Worley & D. B. Lawrence. 1971. Plant diversity in a chronosequence at Glacier Bay, Alaska. Ecology 52:55-69. Bowman, Hacker & Cain (2017), Fig. 17.10, after Reiners et al. (1971) Ecology

Disturbance & Succession Primary succession along the Glacier Bay chronosequence Please do not use the images in these PowerPoint slides without permission. Chapin, F. S. III, L. R. Walker, C. L. Fastie & L. C. Sharman. 1994. Mechanisms of primary succession following deglaciation at Glacier Bay, Alaska. Ecological Monographs 64:149-175. Soil conditions generally improved with successional age Bowman, Hacker & Cain (2017), Fig. 17.11, after Chapin et al. (1994) Ecological Monographs

Disturbance & Succession Primary succession along the Glacier Bay chronosequence Positive, negative, and neutral influences occur through succession Please do not use the images in these PowerPoint slides without permission. This is consistent with facilitation, tolerance, and inhibition all operating under particular context-dependent circumstances. Bowman, Hacker & Cain (2017), Fig. 17.12, after Chapin et al. (1994) Ecological Monographs

Alternative Stable States Strong interactor species appear to be especially important for determining the trajectory towards alternative stable states. It is difficult to establish the existence of true alternative stable states, as opposed to different abiotic conditions in the sites. Please do not use the images in these PowerPoint slides without permission. Sutherland, J. P. 1974. Multiple stable points in natural communities. American Naturalist 108:859-873. Bowman, Hacker & Cain (2017), Fig. 17.17, after Sutherland (1974) American Naturalist

Alternative Stable States If a strong interactor species pushes a community into an alternative stable state, even once that interactor species is removed the community will remain in the alternative state Please do not use the images in these PowerPoint slides without permission. Beisner, B. E., D. T. Haydon & K. Cuddington. 2003. Alternative stable states in ecology. Frontiers in Ecology and the Environment 1:376-382. In ecology, hysteresis refers to the existence of different stable states under the same environmental conditions. Bowman, Hacker & Cain (2017), Fig. 17.18, after Beisner et al. (2003) Frontiers in Ecology & the Environment