Examination Second Review Questions EHUF473 Restoration Ecology
1. Describe how you might restore a prairie ecosystem (tell me what kind of prairie) a) if the original vegetation was completely eliminated when you got there, b) if there were some good elements of the original ecosystem present. In the first instance, I would institute whatever cultivation regime that was necessary to eliminate a weed seedbank, then plant native prairie seeds or plants, then re-introduce fire if indicated. In the second instance, I would selectively remove non-natives or woody species (mowing, hand-cutting, fire). Then, introduce a regular fire regime if indicated. Then add in native species by seeding or planting liners. 2. What is the overriding ecological condition that makes a prairie, and how does this affect the way that restoration must be done there? Prairies are too dry during the late part of the growing season to support woody vegetation. Or, they are pretty dry and burning has eliminated woody species. Means you have to plant when there is adequate moisture (fall, late winter) and use mechanical control or fire to keep native herbaceous plants dominant. 3. Why does fire work as a management tool on prairies? Most prairie species are adapted to fire; many woody invasives are not. Also, the bunchgrass form may be better adapted to tolerating a cool burn than rhizomatous species of grasses. 4. Are oak woodlands stressful environments? Why? Are oak trees stress tolerators? Explain. For trees they are, because they are on the dry edge of the climatic zone that will support trees. They are also fire-associated environments. Oak trees have the characteristics of stress tolerators. They grow slowly, have deep tap-roots for mining scarce water supplies, can tolerate drouth and flooding, have adaptations to burning. They may be evergreen and sclerophyllous, other stress modifications. 5. Is there a relationship among fire, the environment in which oak woodlands occur, and the life history and strategy of oaks? Explain. Fire often is ignited in the dry prairie by lighting or by people. Oak has evolved a resistance to fire (thick bark, stump sprouting). Oak is a conservative species and so can grow slowly, grow back from fire damage, and can reseed into areas that other woody plants have been burned out of. 6. How would you obtain and use acorns in an oak woodland restoration in western Washington.? Pick them off of ground or trees, sow them in oak leaf mulch, and plant young seedlings
the next year. Or, direct-seed in the fall under an oak leaf mulch. 7. Describe some techniques, in addition to planting wetland plants, for restoring freshwater wetlands? Building levees or dikes to trap additional water, or excavating. Plugging drainage ditches or drainfields. Breaching stock tanks. Spreading wetland soil, innoculation, prairie hay. Water level manipulation: low water in summer for annual plant growth. Low water in spring to reinvigorate excessively flooded sites. High water for a while. 8. Go through and describe the steps for creating or restoring a freshwater wetland. Set goals and objectives, find sites, assess sites, site plan, design (earthwork, hydrology, planting plan), construction, plant procurement (order material or propagate, grow, store, transport). Plant installation, maintenance and management, invasive species control plan, monitoring. 9. Is site grading and final elevation of a wetland restoration site a) not critical, b) important, or c) critical? Explain your answer and give an example. Site grading is critical. It is critical because most wetland plants must exist within an elevation window of about a foot and a half. Plants may actually prefer only part of that window (seasonally saturated, permanently flooded, etc.) 10. Of what value is the ability to initially manipulate water levels in a wetland restoration project? Give some examples. To bring up vegetation that is germinating or resprouting. To grow summer annuals for organic material or waterfowl food. To kill invasive plants, fish or animals. To allow regrowth of excessively flooded sites. 11. Explain how and why surface water salinity and elevation interact in a coastal wetland, and give some examples of how this will affect attempts at restoration. Higher elevation sites in a salty part of a coastal wetland may actually accumulate and concentrate salinity. Restoration in such areas might only work after autumn (or other seasonal) storms have decreased salinity (or after floods, hurricanes, etc.) 12. Why does the simple act of dike breaching sometimes result in the restoration of a coastal wetland? Because it is possible to revegetate a site simply by restoring hydrology, if it has not lost surface elevation, if a good source of propagules exists nearby, and if there are not serious invasive plant or herbivore problems. 13. Why might dike breaching not be effective, by itself, in the restoration of a coastal wetland? Because the surface may have subsided. Salinity may have changed (dam on a river upstream). No propagules may be around. There may be invasives or herbivores. 14. The connector dike in San Diego has been used as an example of a failed coastal restoration
site. Explain why it is supposed to have failed. Some argue that it was a success. Explain why it might be described as a success. It failed because Spartina foliosa did not reach its normal height, thus was unable to support clapper rail nests. The plants were stunted because they were planted in sandy soil that had inadequate nutrient pools and poor cycling. The site did support the California least tern and a plant species, Cordylanthus maritimus. 15. What are the overriding environmental conditions in the arctic impact that the ways that restoration can be done? There is a short growing season. Soils are poorly developed and there is permafrost. It is cold. There are few days above freezing. It is dry in much of the arctic. Nutrients are lacking in much soil, or tied up in peat in other soils. Thermokarst changes environmental conditions. 16. What is thermokarst and what has an impact on how serious a disturbance it may become? It is the melting out of ice, which is a substantial component of many arctic soils. Ice richness, slope and clay increase its effect. Wet sites are more sensitive, but respond more quickly than dry. Very much damage leads to thermokarst and little recovery occurs. 17. What impacts do the transportation systems in the arctic have on the environment? Heavy use of gravel. Creation of pads and roadbeds. Dust. Inteference with migration routes. Blockage of drainage and streams. 18. An oil-well and storage tank pad has been decommissioned. The pad was eight feet deep and the gravel has now been removed so that there is only one foot of depth above the former tundra. How would you restore this site? Seed remaining pad with native grasses that are dry-site adapted, and walk away, especially if on an ice-rich soil. 19. What kinds of sites are most sensitive to disturbance in the arctic, and why are they also the most resilient sites? Very moist sites are sensitive, but they rebound quickly because blue-green algae are more productive and can put nitrogen back into the soil. 20. How does the alpine tundra differ from arctic tundra? Alpine tundra will have greater temperature fluctuations, high light energy, uv radiation, soil creep. 21. What are some tools for restoration in the alpine? Creation of soil retaining structures to retard erosion. Greenhouses. Mulch mats. Volunteer parties, helicopters. 22. How serious a threat is camping and associated recreational uses to alpine habitat? If you
were manager of a park in the subalpine and alpine zones, and were given the job of restoring an old public campsite, go through the steps that you would take to accomplish the restoration. Fence off site. Scarify soil or add soil if lacking Protect against erosion. Propagate plants from surrounding system. Plant and mulch, seed into mulch. 23. What are the overriding environmental conditions that might effect your attempts to restore a degraded site in an arid or desert environment? There is a very small window when moisture is adequate, and in warm deserts there may be years with not adequate moisture. Soils have little OM or nitrogen. 24. Often, seeding is the only method of restoration that has any chance of being effective in a desert or arid environment. Can you explain why that is so? Large plants without well-developed root systems cannot be transplanted. They normally must grow and rooting must develop as moisture is available. Seeds can be easily sown, and if no rainfall follows their application, they can be sown again next season without excessive expense. 25. How does eelgrass reproduce, and how can we take advantage of that for restoration? Eelgrass produces seeds, but also spreads rhizomatously. Seeds can be collected and propagated in marine tanks. Rhizomatous spread allows plants to be separated and multiplied, and also means that plants will fill out a site. 26. What kinds of issues/conditions might you be concerned with prior to conducting restoration of an eelgrass meado...