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Methods of vegetation sampling: blm/nstc/library/pdf/samplveg.pdf

Methods of vegetation sampling: http://www.blm.gov/nstc/library/pdf/samplveg.pdf http://www.blm.gov/nstc/library/pdf/MeasAndMon.pdf Range cover types of the US: ftp://ftp-fc.sc.egov.usda.gov/GLTI/technical/publications/cover.pdf Ecological site inventory technical reference:

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Methods of vegetation sampling: blm/nstc/library/pdf/samplveg.pdf

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  1. Methods of vegetation sampling: http://www.blm.gov/nstc/library/pdf/samplveg.pdf http://www.blm.gov/nstc/library/pdf/MeasAndMon.pdf Range cover types of the US: ftp://ftp-fc.sc.egov.usda.gov/GLTI/technical/publications/cover.pdf Ecological site inventory technical reference: http://www.blm.gov/nstc/library/1734-7direct.html Indicators of rangeland health: http://www.blm.gov/nstc/library/pdf/1734-6.pdf

  2. Seminars • EECB seminar Thurs 4:00 PM OSN 120. Dr. Larry Stevens, Grand Canyon Wildlands Council. “Biogeography of the Grand Canyon, and Colorado River Management”.

  3. Reading • Textbook Chapter 12 and 13 • Sparrow, A., M. Friedel, and D. Tongway. 2003. Degradation and recovery processes in arid grazing lands of central Australia part 3: implications at landscape scale. Journal of Arid environments 55: 349-360.

  4. Outline • Case study: identifying communities and relating to environmental conditions • Student case studies • Productivity – plants and ecosystems • GPP, NPP, and Efficiency • Global and environmental patterns of NPP • Production in forest VS rangeland • Factors influencing productivity – fire, herbivory, nutrient pulses, etc. • Climate change, CO2 accumulation, and carbon sequestration

  5. Species interactions and restoration • Rangeland in Kenya: high productivity, high rainfall (600mm/yr). • Massai traditionally nomadic pastoralists but now becoming sedentary. • Can no longer move when pasture bad; must use land stewardship. • Land highly overgrazed, and desertification widespread (80%?).

  6. Fertile islands? • Aloe secundiflora shrubs have vegetation around them even in eroded areas • Aloe is unpalatable as an adult • Positive effect appears to extend beyond range of aloe canopy • Potential facilitation effect?

  7. Theory of facilitation • Presence of one plant species enables others to persist • One species ameliorates environment; facilitation important in harsh conditions. • Positive environmental effects outweigh possible negative competition effects • This may switch with plant life stage (e.g. facilitate as seedling, compete as adult)

  8. Additional Value of Aloe? • Aloe is a medicinal plant; “poached” from the wild for sap • Massai ranchers need cash rather than cattle • If planting aloe can facilitate range recovery, is this a “win-win” situation for Massai?

  9. What ecological interactions/processes need to be considered?

  10. Aloe as facilitator • Quantification of spatial pattern (circumstantial evidence) • Basic experimentation on species interactions (does aloe facilitate other species?) • Establishment of dryland agriculture and range restoration program Work by Elizabeth King, UC Davis

  11. Aloe as facilitator • Quantification of spatial pattern (circumstantial evidence) • Spatial pattern: aloe plants retain soil, have higher soil fertility, more litter, greater soil seed bank, higher cover and diversity of surrounding vegetation. Soil retention

  12. Aloe as facilitator • Quantification of spatial pattern (circumstantial evidence) • Basic experimentation on species interactions: • Plant Aloe, compare to thorns (grazing protection) and control (soil disturbance) • Plant Cenchrus cilliaris, observe growth. • Cenchrus growth substantially enhanced by Aloe, effect extended away from plants

  13. Aloe as facilitator • Quantification of spatial pattern (circumstantial evidence) • Basic experimentation on species interactions (does aloe facilitate other species?) • Establishment of dryland agriculture and range restoration program • Growing and planting Aloe and Cenchrus on Massai group ranch; hope to harvest Aloe sap as cash crop and graze between rows.

  14. Your turn… • List management issues/projects you know of in range and forest ecosystems. • Which of the ecological processes or interactions we have discussed so far do you need to understand? • Can you make predictions or recommendations based on your understanding of the ecological systems?

  15. Future lectures… • 10 minutes at beginning of class for students to present case studies pertaining to previous lecture’s topic. • Start Wed – topic is measurement and definition of communities…

  16. Community: working definition • Two concepts: continuum or community type • Continuum – vegetation changes along gradients of environmental conditions. Species may co-occur by chance/shared environmental tolerances. • Community type – species occur in association, such aggregations have adaptations holding them together as units. Show boundaries between them.

  17. Community: working definition These two concepts are not mutually exclusive; both patterns occur to a greater or lesser extent in natural vegetation. Sharpness of community boundaries often relate to abrupt changes in site conditions (e.g. serpentine soil patch). Community best thought of as a “level of organization” rather than a distinct entity with boundaries.

  18. Community: working definition • Visually distinct features of a landscape. • Interpreting composition, stand structure, dynamics, and spatial distribution requires understanding of site conditions, disturbance, history, and ecological processes. Barnes et al 1998. • Forest type – a community defined solely on the basis of canopy species • Ecotone – transition area between two community types. e.g. grassland and forest: broad change in community due to longer term climate/environment BUT exact position of treeline depends on local disturbance, competition, history, etc.

  19. Community attributes • Physiognomy • Architecture, LAI, life-forms, phenology, etc. • Composition, spatial pattern, and diversity • Nutrient cycling • Demand, storage, rate of cycling, efficiency • Productivity • Control of environment • Plant-environment feedback • Change over time • Succession, stability, migration

  20. Community structure • Physiognomy – physical structure of vegetation (appearance, structural complexity, architecture, growth forms) • Why is vegetation structure important?

  21. Community structure • Leaf Area Index – LAI. • Square meters of leaf area per square meter of ground. • Higher LAI, usually more sunlight intercepted, greater efficiency and productivity. e.g. tropical forest LAI=11, uses 1.5% incident radiation, desert LAI=1, uses 0.04% incident radiation.

  22. Life forms • Characteristic structure of plant…life form will affect disturbance tolerance, physical structure, regeneration, etc. • Raunkiaer (1934) classified plants based on location and protection of meristems and/or reproduction (see handout).

  23. Community composition • Communities composed of species… are all species necessary to define a community? • Biodiversity: • What is biodiversity? • What does diversity signify? Why is it important? • Types of diversity: richness, evenness, functional diversity…others?

  24. Patterns of diversity • Species and individuals distributed in different ways in different communities. • Spatial patterns • alpha diversity – diversity or richness in species within a habitat • Beta diversity – diversity of habitats in an area; “species turnover” • Gamma diversity – diversity of a region

  25. Upcoming lectures • Next lectures will address aspects of communities and diversity concepts: • Mar 3: productivity • Mar 8-9: plant-soil interactions, nutrients • Mar 10: disturbance and succession • Mar 22: state and transition dynamics • Mar 24: fire ecology and climate change • Mar 29: functional groups and biodiversity

  26. Example of community description • Ecological sites – BLM, USFS, and NRCS • Used for both range ecological sites and forest ecological sites. • Details of range site description given in handout • Details of forest site description given in national Forestry Manual: • ftp://ftp-fc.sc.egov.usda.gov/NSSC/ National_Forestry_Manual/2002_nfm_complete.pdf • Range and forest type sites are differentiated by HISTORIC VEGETATION.

  27. Ecological site • Definition: A distinctive type of land with specific physical characteristics that differs from other types of land in it’s ability to produce a distinctive kind and amount of vegetation. • Clementsian?

  28. Ecological site description • Vegetation is product of: • Soils • Topography • Climate • Disturbances • Differentiated by: • Differences in dominant plant species • Changes in proportion of plant species • Changes in productivity

  29. Ecological site description • Utility of site descriptions… “Rangeland landscapes are divided into ecological sites for the purposes of inventory, evaluation, and management”

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