Historical context Repairing Damaged Processes/ Directed Vegetation Change Readings: Whisenant Chapter 3 & 4 Modify site to fit desired species Problems Cost Not sustainable Works/ doesn t work http://www.homes4saleky.com/kentucky-farms%20200-300000.asp Repairing Primary Processes Site is evaluated based on its potential Severe degradation getting anything back is good Mild degradation move to more desirable species Main problems erosion, runoff, infiltration 2 nd level nutrient cycling, salinization, landform issues (gullies), compaction Structure Long-term plants are needed Short term Ripping can loosen compaction but any existing vegetation can be lost. Ripping moves the compaction layer down in the soil and can move salts to the surface Loose sediments can be compacted to prevent their further movement http://mtbest.net/forest_establishment.html http://www.prospectwines.com/gallery.php http://muextension.missouri.edu/explore/agguides/agengin/g01630.htm http://www.extension.umn.edu/cropenews /2003/03MNCN26.htm 1
Stability Keep slope in place long term vegetation Terracing/contouring Hay bales Logs Other http://ecorestoration.montana.edu/stormwater/photos/browse.asp?offset=5 http://tilz.tearfund.org/publications/footsteps+11-20/ Footsteps+15/How+soil+erosion+happens.htm www.chuckhaugenconservationfund.org/weed.php/ www.forestoration.org/service_detail.php Moisture Too wet long term establish vegetation Drain Using adapted plants is a better option Sometimes need to drain for salinity or toxicity but again adapted plant selection is better Too dry long term establish vegetation Contour, dam, sculpt and otherwise try to increase interception, direct runoff and capture water. Macronutrients In order of their importance: Nitrogen (N), phosphorous (P), and potassium (K). Nitrogen is often seen as the most limiting Easily lost Cycled through decomposition of OM Too much is bad many natives do well with little Fertilization may be needed 5-10 years! Legumes can fix N from the air but need P Micronutrients Calcium (Ca), magnesium (Mg), and sulfur (S) are also commonly called macronutrients Aluminum, arsenic, boron, cadmium, chlorine, copper, iron (sometimes a macronutrient), lead, manganese, sodium, zinc, and others. ph Usually the problem is acid soils Oxidation of pyrites Too much organic matter! Lime (CaCO3) can be used to amend the soil Effect can be short lived Effect may only be surface Plants can slowly change ph 2
Toxicity Organisms Heavy metals Organic mulch Tolerant vegetation Capping Sodium/salinity Tolerant vegetation Irrigation/ drainage Amend with gypsum Nutrient cycle depends on organisms and OM in soil Organisms can be cultured and added Usually need local source Cost? Effectiveness has limited number of demonstrations Plants adapted to poor sites need things to cycle slowly N tends to drive the cycle. OM questions How much does it cost? How much is available? How much does it cost to move and apply it? Are there any contamination/ toxicity/ bacteriological or other issues with it? Are there any neighbor issues with it? Plant residues Sawmills sawdust Paper milling or paper recycling Papermill sludge, waste paper Grain crops straw Cotton Ginning cotton trash Wood recycling wood chips Most are not associated with rangelands Manure Associated with feedlots, hog barns, poultry operations. Too high in N Odor trouble Can trigger clean water act Can contain toxic bacteria How to spread and/or incorporate? sawg.cas.psu.edu/photos.html http://environmentalsoils.cas.psu.edu/scootackbiosolids.html 3
Sewage sludge Not always readily available Can contain toxins, harmful bacteria, heavy metals Odor Usually a liquid heavy + must be sprayed to apply Hauling Composts Requires a second step beyond gathering organic materials Have to compete with other users Good product often sold by above mentioned producers http://organic.tfrec.wsu.edu/compost/imagesweb/compapp.html http://www.nrc.govt.nz/special/soe.2002/fresh.water/surface.water.quality/5-5-index.shtml Peat Where are the peat bogs? Is it sustainably harvested? Too far from most arid lands to be viable. What happens to soil without plants? Seeds Insects Microbes/ Fungi Nitrogen cycle/ Organic matter Nutrients Stockpiles http://www.gardenscapeinc.com/products/sphagnum_peat_moss.htm www.reynoldsinternational.com/app_detail.asp Vegetation change System = (nutrients + soil + water + plants + animals) * sunlight Should be roughly in balance where in + out = Zero Nut + Soil + water + plants1 = X Nut + Soil + water + plants2 = X or X-1? Can the conversion occur without unacceptable loss? Goals Repair = as close to balance as possible How to pick the vegetation goal Reference areas Historical accounts Legal requirements/ landowner requirements What will grow there/ what will halt erosion, etc. Public perception What seeds are available 4
Goals Composition species and abundance Structure vertical arrangement of live and dead vegetation Pattern horizontal arrangement of vegetation Function ecological processes Vegetation dynamics and resilience Understanding vegetation change Processes and context Uncertainty Temporal and spatial variability Change is cumulative effect of many events rather than a single operative mechanism Multiple stable states with thresholds Conceptual Models Succession State and transition Spontaneous generation Facilitation, Tolerance, Inhibition Succession Bare soil http://www.geocities.com/lacopita_research_area/succession.jpg http://www.ontarionature.org/educate/jeopardy/images/succession.gif Can move through the states forward and backward depending on the time allowed between disturbances Pioneer species Climax vegetation http://www.geo.arizona.edu/antevs/nats104/00lect20sucn2.gif 5
Directing succession Species performance Site availability Species availability Starting from bare soil Succession a progression of plants until a climax community is established. Each sere of plants facilitates the next sere. Preemption what ever plants get there first dominate indefinitely Episodic preemption given the same seed bank, the community established will be different depending on the weather pattern of the establishment year Starting from bare soil (cont) Competitive exclusion species will change until the most competitive is dominant and it will exclude newcomers Continuous instability species shift year to year and no long term dominance by any one species or group occurs Inertia driven community established but climate shifts make it impossible to reestablish State and transition http://frap.cdf.ca.gov/projects/hardwood_expert/building_state/images/snt_a.gif http://www.glti.nrcs.usda.gov/projects/images/range-health-workshop/wash-figure3.gif 6
Stability Large scale phenomenon Independent of disturbance small patches of disturbance can fit into a stable mosaic Human construct We are usually considering 20 or more years to be stable arguable What part of the plant life cycle Seed dispersal Safe site Germinable conditions Moisture Light Temp Establishment Safe from predators Safe from herbivory What part of the plant life cycle Growth Reproduction First year Every year Seedbank Seed dispersal Death Litter layer Decomposition and incorporation into soil carbon pools Release of stored nutrients Roots leave pores in the soil 7