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Ecological Development Terminology
• Disturbance – an event, either natural or anthropogenic, that affects an ecosystem’s structure, content or function (Clewell & Aronson, 2007)
• Succession – process that follows a disturbance to an ecosystem by which biota sequentially occupy and replace each other over time (Kimmins, 1997)
• Chronosequence – a sequence of communities that characterizes a range of time since a disturbance (Molles, 2008)
Primary succession – when a community develops on a site that isn’t established with biota i.e. a sand or silt
bed, a body of water, volcanic flow (Cunningham et al., 2006)
http://www.sciencebitz.com/wp-content/uploads/2008/01/primary-success.jpg
Primary Ecological Development
• Pioneer Species – the first hardy species (generally microbes) that colonize an area o I.e. - Lichens, moss are able to tolerate harsh
conditions creating patches of organic material where debris accumulates providing soil where seeds are able to germinate
o Communities become more diverse and competitiveo The environmental conditions change and become
richer, there is increased moisture and nutrient availability and shelter for species
Cunningham, et al., 2006
Secondary Ecological Development
• Secondary Succession – abandoned agricultural area or deforested site resulting in bare soil
o Initially colonized by annuals that are opportunistic, r-selected species (Abella’s lecture)
o Perennials replace annuals
Secondary succession – when a community exists and is disrupted by a fire or flood, deforestation, plowing or mining, and then replaced by another community type
(Cunningham et al., 2006)
Image source: http://www.sciencebitz.com/wp-content/uploads/2008/01/secondary-success.jpg
Glacier Bay, Alaska
• 1794 – Captain George Vancouver
• 1879 – John Muir• 1915 – William Cooper
o Observed that as the glacier retreated different species established themselves
o The site was ideal for studying succession because of the past history recorded
Theory
• In both primary and secondary succession it was observed that communities reach a state that becomes resilient to further change
• Analogy was made comparing the individual organism development and ecosystem development
• It was observed that individual species and communities both began at a juvenile state and developed reaching a complex or mature formCunningham, et al., 2006
Henry Chandler Cowles
• Cowles was among the first to formally identify the theory of succession through his 1899 paper The Ecological Relations of the Vegetation on the Sand Dunes of Lake Michigan
Integrated vs Individualistic
• Integrated Hypothesis - F. E. Clements, that a community is an assemblage of closely linked species, locked into association by mandatory biotic interactions that cause the community to function as an integrated unit
• Individualistic Hypothesis - H. A. Gleason, that a plant community is a chance assemblage of species found in the same area simply because they happen to have similar biotic requirements.
Clements Community-unit theory
• Frederic E. Clements – likened ecosystem succession to a relay where species replace one another in predictable groups in a predictable order (Cunningham, et al., 2006)
• argued that each ecosystem had a characteristic climax community determined by climate and if undisturbed would reach a characteristic composition
Henry GleasonIndividualistic Hypothesis
• Gleason argued succession was a less predictable process
• Emphasized chance individual species assemblages rather than community associations
• Whitaker and Curtis continued his research with the “species-individualistic model” or “alternative continuum model” plant communities change gradually along complex environmental gradients
• Rivet Model - Paul and Anne Ehrlich, that many or most of the species in a community are associated tightly with other species in a web of life.
• Redundancy Model - Henry Gleason and Brian Walker, that most of the species in a community are not tightly coupled with one another (that is, the web of life is very loose).
Biomass Accumulation Model
Image source:www.biol.vt.edu/faculty/valett/strmecol/.../Lect%2019%20Succession.ppt
Disturbance Adapted Ecosystems
• Some ecosystems never reach a “stable” state in the Clements sense but rather are used to periodic disturbances like fires or floods
• Fires - eliminate competition and assist in seed germination
• Disturbances are a natural part of some ecosystems
Image source: http://research.uvu.edu/Gray/previous.htm
Invasive Species
• Succession requires a continuous introduction of species (Cunningham, et al., 2006)
• This can be problematic if a non-native introduced species becomes invasive or noxious
Image source: http://www.cal-ipc.org/ip/management/plant_profiles/Bromus_madritensis.php
ReferencesAbella, S. R. 25 March 2010. Disturbance and Plant Succession in the Mojave and Sonoran Deserts of the
American Southwest . Int. J. Environ. Res. Public Health 2010, 7, 1248-1284; doi:10.3390/ijerph7041248.
Cunningham & Cunningham. Principles of Environmental Science. 2006.
Gleason, H. A. 1926 - The individualistic concept of the plant association. Bull. TorreyBot. Club 53: 7-26.
Goodall, D. W. 1963 - The continuum and the individualistic association. Vegetation I : 297-316.
Molles, M.C. Ecology Concepts and Applications. 2008.
Whittaker, R. H.. 1972. Evolution and Measurement of Species Diversity. Taxon. Vol. 21, No. 2/(May, 1972), pp. 213-251Published by: International Association for Plant Taxonomy (IAPT) http://www.jstor.org/stable/1218190
Bridging Succession Theory and Ecological Restoration
Presented by:Gretchen AndrewENV 794March 21, 2011
Image source: http://www.matthew-and-maria.com/?p=25
Presentation Outline
• Relevance of Topic• Arguments & Justifications• Mutual Benefits• Application of Successional
Theory in Restoration• Conclusion
Image source: desertmuseum.org
Why is this topic important?“Practicing restoration outside the framework of succession may be likened to building bridges without attending to the law of physics.” Walker et al., 2007b
“Current management focuses on eliminating weeds rather than understanding and manipulating the ecological processes and mechanisms promoting invasion and species compositional changes.” Sheley et al., 2006
“Restoration is the acid test of our ability to understand not only how ecosystems are assembled and held together but also how they change over time.” Walker et al., 2007a
Arguments Against the Application
• Successional patterns can be unpredictable• Succession too slow a process to apply to
restoration• The differences between the two disciplines
are too great– Time scales– Spatial scales– Subject matter– Paradigms
Photo source: exchristian.netWalker, et al. 2007b
Justification for the Application
• Restoration already relies on broader successional patterns of change for its success
• Succession is all about how species & substrate change over time, & restoration is all about manipulating those changes
• Each discipline can offer understanding & insights to the other
Photo source: asianjobportal.com
Walker, et al. 2007b
What Succession Offers Restoration
• Long-term perspective• Short-term predictions• Reference system for likely
outcomes• Generalizations of possible
trajectories• Understanding of
mechanismsWalker, et al. 2007b
Image source: clipart.com
What Restoration Offers Succession
• Practical data– Corrections to abiotic constraints– Species interactions in particular circumstances– Sustainability of particular succession
communities• Practical tests of successional theory– Use of controls– Treatment comparisons– Data / Statistical analysis– Peer-reviewed results
Image source: lyonperepente.frWalker, et al. 2007b
Major Phases of Succession
• Amelioration• Dispersal• Colonization• Establishment• Species assembly / ecosystem development
– Also represent the major constraints to successful restoration
– How might succession theory be applied to overcoming these restraints?
Image source: ecostudies.org
del Moral et al. (2007)
Amelioration of Abiotic Constraints• Causes
– Natural phenomenon– Human activities
• Role (in succession & restoration)– Advance recovery of structure & function– Improve fertility– Reduce toxicity– Improve growing conditions for plants
• Natural processes– Wind deposits dust, pollen, seeds, insects– Water erosion removes overburden– Frost-thaw cycle fractures rocks– Wind erosion forms microtopography (safe sites)
Image source: superstock.com
del Moral et al. (2007)
Successional Theory Applied to Amelioration
• Lessons from succession– Stress restricts establishment– Safe-site creation important– Low fertility may increase diversity
• Application to restoration– Reduce toxicity– Create safe-sites– Increase heterogeneity
Image source: debudeodhar.com
del Moral et al. (2007) ; Sheley et al. (2006)
Example of Amelioration in Restoration
Neil B. Reid, N. B. and M.A. Naeth, 2005. Establishment of a Vegetation Cover on Tundra Kimberlite Mine Tailings: 2. A Field Study. Restoration Ecology, 13(4): 602-608.
ekati.bhpbilliton.com www.monitoringagency.net/PhotoGallery
Dispersal
• Role– Improve colonization– Increase functional group diversity
• Obstacles – Depleted seed bank– Impermeable or inhospitable
habitats• Natural processes– Landscape permeability
Image source: alnus-eco.com
del Moral et al. (2007)
Successional Theory Applied to Dispersal
• Lessons from succession– Regional species pool is limited– Chance is important
• Application in restoration– Sow/introduce plant species– Install bird perches
del Moral et al. (2007) ; Sheley et al. (2006)
Example of Application in Restoration to Improve Dispersal
Martínez-Garza, C. and H.F. Howe, 2003. Restoring tropical diversity: beating the time tax on species diversity. Journal of Applied Ecology, 40: 423-429.
Colonization
• Role– Speed up ecosystem development– Decrease competition by invasives
• Obstacles– Few large-seeded spp on isolated sites– High seeding failure rates– Competition– Seed predation
• Natural processes– Spontaneous recolonization– Trajectories started by ruderal species– Trees & shrubs provide refuge to birds
& protect seedlings
Image source: desertmuseum.org
del Moral et al. (2007)
Successional Theory Applied to Colonization
• Lessons from succession– Disharmony characterizes early vegetation– Survival probabilities low & random– Natural dispersal doesn’t provide most colonists
• Tools for restoration– Introduce array of species– Plant more species than are required
del Moral et al. (2007) ; Sheley et al. (2006)
Example of Application in Restoration to Improve Colonization
Slocum, M.G. and C.C. Horvitz, 2000. Seed arrival under different genera of trees in a neotropical pasture. Plant Ecology, 149(1): 51-62.
Establishment
• Role– Allow seedlings to grow fast enough to survive changing
conditions• Obstacles– Drought– Excessive light or heat– Herbivory
• Natural processes– Mechanisms that trap seeds– Stable surfaces– Safe-sites
Image source: travelwebshots.comdel Moral et al. (2007)
Successional Theory Applied to Establishment
• Concepts from succession– Functional redundancy– Facilitation– Inhibition
• Tools for restoration– Introduce several species in several functional groups– Provide safe-sites– Plant saplings in scattered clusters to provide mutual
support– Protect seedlings from herbivores (e.g., fencing)
del Moral et al. (2007)
Example of Application in Restoration to Improve Establishment
Urbanska, K.M., 1995. Biodiversity assessment in ecological restoration above the timberline. Biodiversity & Conservation, 4: 679-695.
Jakobshorn, Davos, Switzerland
Conclusion
• Succession theory and ecological restoration are inherently linked
• Despite the differences between the two disciplines, each has much to offer the other in terms of knowledge & insights
• Practical strategies exist for applying succession theory to restoration projects
Photo source: fr.treknature.com
Works Citeddel Moral, R., L. Walker, J. Bakker, 2007. Insights gained from succession for the restoration of
landscape structure and function. In: Linking restoration and ecological succession, Walker, L. R., Walker, J., R.J. Hobbs (Eds), Springer, New York, N.Y., 1-18.
Martínez-Garza, C. and H.F. Howe, 2003. Restoring tropical diversity: beating the time tax on species diversity. Journal of Applied Ecology, 40: 423-429.
Neil B. Reid, N. B. and M.A. Naeth, 2005. Establishment of a Vegetation Cover on Tundra Kimberlite Mine Tailings: 2. A Field Study. Restoration Ecology, 13(4): 602-608.
Sheley, R.L., J.M. Mangold, J.L. Anderson. 2006. Potential for successional theory to guide restoration of invasive-plant-dominated rangeland. Ecological Monographs, 76(3):365-379.
Slocum, M.G. and C.C. Horvitz, 2000. Seed arrival under different genera of trees in a neotropical pasture. Plant Ecology, 149(1): 51-62.
Walker, L.R., E. Velazquez, A.B. Shiels. 2009. Applying lessons from ecological succession to the restoration of landslides. Plant and Soil, 324(1-2):157-168.
Walker, L. R., Walker, J., R.J. Hobbs (eds), 2007a. Linking restoration and ecological succession. Springer, New York, N.Y., 190 pp.
Walker, L. R., J. Walker, and R. del Moral, 2007b. Forging a new alliance between succession and restoration. In: Linking restoration and ecological succession. Walker, L. R., Walker, J., R.J. Hobbs (Eds), Springer, New York, N.Y., 1-18.
Urbanska, K.M., 1995. Biodiversity assessment in ecological restoration above the timberline. Biodiversity & Conservation, 4: 679-695.
Ecological Succession- Theory applied to real life examples
Topics of interestSuccession significance and background
Obtaining “equilibrium” Is it possibleDisturbance
Succession examplesProblems facing future restoration efforts and
succession predictions in new areas
Ecological succession studies are particularly important when it comes to addressing concerns about biodiversity loss, climate change, invasive species, and ecological restoration.
Background and the significance of Succession in Ecology
Historical succession models are used as a predictor of changes in biodiversity and ecosystem services impacted by invasive species and climate change.
Understanding succession of different climates, gives restorers a better idea of how to manage these new ecosystem areas.
Invasive species are a concern to ecologists and those relying on succession traits known to an area.
Tamarisk is an invasive species threatening portions of the newly exposed shore line of Lake Mead National Recreation Area.
It is important to address concerns about invasive species when discussing succession because theseinvasives are not part of the “natural” cycle of succession.
Background and the significance of Succession in Ecology cont.
Tree saplings found here at the bottom of a dry river bed. Most of these species will be washed away when the river fills up with water with winter snow melt.
During the dry period, perennials, grasses and some tree saplings have begun to populate this exposed area.
However, this new area will change again with the spring thaw.
Some examples of different types of “succession”
The theory of succession addresses the dynamics. There is not any particular “end-point” as it is always changing.
Forest vegetation pushing up the side of an old cinder cone volcano after eruption This particular site has been a 10,000 year battle up hill.
www.morning-earth.org/graphic-e/Transf-Success.htm
Some examples of different types of “succession” cont.
From another extreme, this forest has been under going succession for a very long time.
Succession example of an old plowed field being encroached upon by vegetation.
Some examples of different types of “succession” cont.
An example of a moderate successional change.
Issues inhibiting the use succession history. Issues scientists are facing in predicting succession:
Perchlorate in the water in Lake Mead- what might this chemical be changing in the succession dynamics on the Lake Mead shore line?
Invasive species- quagga and zebra muscles, tamarisk, brome, Russian thistle
Climate change- temperatures are different than historical succession models of the area
Human interference- both with restoration and continuous disturbance
Factors that change succession possibilities
http://worldwaders.posterous.com/north-brigantine-natural-area-experimental-cl
http://ecology.ucdavis.edu/programs/restoration/ecolrestore.html
“Global warming may intensify the hydrological cycle and lead to increased drought severity and duration, which could alter plant
community structure and subsequent ecosystem water and carbon dioxide cycling.” (Scott, et al 2010)
Drought conditions not usual to an area can have affects on the plant species composition.
As native species die off due to water and moisture changes, it makes way for drought tolerant species to colonize an area, thereby changing the historical pattern of succession.
Characteristic questions facing ecologists:
When does an exotic species become a part of the “natural” ecosystem?
Is the exotic/invasive species part of the larger natural process?
Factors that change succession possibilities cont.
Polish desert succession
Historical maps used to track vegetation and human habits. Land originally used by mining for metallurgy in the 13th century. Narrowed down to primary and secondary succession. Tracked to cyanobacterial communities holding soils for water retention to make way
for annual plants. Time a factor as well moisture levels and disturbances.
Historical and current succession studies
Land was reclaimed beginning in 2009 to restore the area as best as possible to pre-disturbance.
Cannot restore on its own with current conditions.
http://www.krakowpost.com/article/1535
http://web1.msue.msu.edu/iosco/openshoreline.htm
Lake Huron shoreline trends and water elevation changes
Low and high water trends in lakes can have successional trends over time
Riparian species in areas with the most moisture.
With the receding water to low points, the once moist ground is dry and makes way for grasses and then shrubs.
Species composition changes as water levels decline.
Historical and current succession studies cont.
http://web1.msue.msu.edu/iosco/openshoreline.htm
More Great Lakes shoreline images and succession- different beach 3 years apart
Historical and current succession studies cont.
One example from Mono Lake, California
Seed dispersal was studied Although the seeds can travel far, the smooth play surface, lack of wind barriers (to
trap seeds and particulates) kept seeds from being able to establish (Fort et al 2008) There was an abundance of pioneer species but lack of mechanism to establish the
seeds Succession difficult in this situation. Is human interference the best solution when
the problem was human induced?
Historical and current succession studies cont.
http://ecocentric.blogs.time.com/2010/10/18/water-lake-mead-is-at-record-low-levels-is-the-southwest-drying-up/
Lake Mead- a closer to home example
Lake Mead was not originally under water.
Towns that were flooded are now being uncovered due to low water levels.
Exposed area creating new habitat- including Tamarisk and Willow Flycatcher (Bureau of Reclamation was sued).
Historical and current succession studies cont.
http://www.treehugger.com/files/2010/08/lake-mead-lowest-level-since-1956-water-users-conserving-hoping-rain.php
Example of Lake Mead extremes
The Lake was meant to fluctuate due to water demands and yearly water flows.
This makes it challenging to predict succession potential of these areas.
Left: 1983 Right: 2009
Historical and current succession studies cont.
Pollution impacts on desert wildlife?
What is the human impact on future model predictors?
So many unknown variables that historical models can only be used as a baseline.
What are future possibilities and problems?
What are future possibilities and problems?
http://newsnews.org/?p=2749
Nuclear contamination interferences...
In Conclusion
Numerous theories surround succession. The general concept of succession (i.e., primary to secondary) works best
when looking at it from a broad angle. A lot of variables to consider when analyzing and area as potential
restoration habitat or naturally left alone. Different climates and ecosystems have different time characteristics than
others which can influence future grant request work. Is the disturbance “natural” or man-made?
Fire (i.e., lightning or campfire- invasive ground cover providing fuel) Mining Water depletion
Human interference is largely unknown. Pollution Carbon Dioxide and other particulate deposition Radiation
Hoagman, W. J. (n.d.). Open Shoreline Wetlands. Wetlands of the Great Lakes Open Shoreline and Embayed Wetlands. Retrieved March 21, 2011, from http://web1.msue.msu.edu/iosco/openshoreline.htm
Laumer, J. (2012, August 10). Lake Mead At Lowest Level Since 1956: Water Users Conserving, Hoping For Rain Next Year : TreeHugger. TreeHugger. Retrieved March 21, 2011, from http://www.treehugger.com/files/2010/08/lake-mead-lowest-level-since-1956-water-users-conserving-hoping-rain.php
Michalik, B. (2009, September 3). A Desert Revival | Krakow Post. Krakow Post - Poland News, Events, Lifestyle and Travel information. Retrieved March 21, 2011, from http://www.krakowpost.com/article/1535
Niles, L. (2010, October 31). North Brigantine Natural Area experimental closure to study shorebirds - WorldWaders News Blog. WorldWaders News Blog - A Global Pool For News On Shorebirds/Waders. Retrieved March 21, 2011, from http://worldwaders.posterous.com/north-brigantine-natural-area-experimental-cl
Scott, R. L., Hamerlynck, E. P., Jenerette, G. D., Moran, M. S., & Barron Gafford, G. A. (2010). Carbon dioxide exchange in a ‐semidesert grassland through drought induced vegetation change . Journal of Geophysical Research, 115, G03026.‐
Walsh, B. (2010, October 18). Water: Lake Mead Is at Record Low Levels. Is the Southwest Drying Up? - Ecocentric - TIME.com. Ecocentric - A blog about all things green, from conservation to Capitol Hill - TIME.com. Retrieved March 21, 2011, from http://ecocentric.blogs.time.com/2010/10/18/water-lake-mead-is-at-record-low-levels-is-the-southwest-drying-up/
Young, T. P. (n.d.). Graduate Group in Ecology. Ecological Restoration Information. Retrieved March 21, 2011, from http://ecology.ucdavis.edu/progr
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