Ecology of the Southwest
Exam 2 – Study Guide
Use this Study Guide to help you organize your notes & your thoughts as you prepare for our second exam. You should ALSO visit the links to each day’s topic on the Website Syllabus: there are usually questions on each of these pages that you should be able to answer, and many of the “Assess-Goals” questions will show up on the test!
Predictable zones or bands of vegetation @ diff. elevations
what limiting factors determine upper vs. lower limits of zones? (remember – they’re
not the same!)
what happens to elev. of life zones as you travel N or S?
Why are they tilted, & which way do they tilt?
How distinct are the life zones? Do they change abruptly, or do individual species
appear & disappear at different elevations?
apply this to what you saw on the….
JUNCTION CR Field Trip:
vegetation patterns - what plant communities?
distributions & boundaries of plant communities, nature of spp distributions
For each Life Zone, be able to name the major plant communities we discussed, & conditions where they thrive.
**For all of these communities, be able to name an indicator animal & the dominant plants!!
Alpine Tundra – plant adaptations to harsh conditions
Treeline - what causes this feature, & at what elevation does it occur in our area?
Mountain Forests:
Subalpine Life Zone -
High Pine Forest
in Great Basin mtns.; 2 pine spp = dominant; disturbance?
Spruce-Fir Forest
fire disturbance rare; frequency & intensity?
Aspen Groves
aspen capitalize on disturbance
Lodgepole Pine Forests
N. Rockies dominant (not SW); fire-adapted sp (how so?)
Mixed Conifer Zone - intermediate zone that we discussed only briefly
Montane Life Zone -
Ponderosa Pine/Oak & Douglas Fir
frequent ground fires = rule
different micro-habitats favored by pine vs. fir
3-way mutualism of Abert’s squirrel, fungus (myccorhizae &
truffles), pine
Disturbance history in SW forests
how we know about historical forest structure/disturbance (Vallecito Lab)
fire “regimes” – frequency & intensity (Table) - be able to classify each major habitat we discuss in this table:
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HIGH FREQUENCY |
LOW FREQUENCY |
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HIGH INTENSITY
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LOW INTENSITY
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Ponderosa Pine forest history
Human land-use history in SW forests – in Ponderosa Pine forests
human land-use:
impacts of logging – grazing – fire suppression
interactions between these variables, that caused the switch from historically OPEN pine forests to modern CLOSED/Dense forests:
grazing
logging
fire frequency
fire intensity
ponderosa pine adaptations
pine seedlings
ground fire
crown fire
10 a.m. rule (fire suppression)
competition
grass & shrubs
Fire Wars video
history of fire policy, management of public lands past & present
Foothills Life Zones:
COLD DESERT HABITATS:
Cryptobiotics (Biological soil crusts) on Colo. Plateau; Blackbrush grasslands
role in cold desert communities; key players; why considered keystone? threats & implications
Sagebrush Grasslands in Great Basin, and sage grouse
role & origin of cheat grass in cold desert communities; changes in fire regime?
threats & implications & future potential
Pinyon-Juniper Woodland
pinyon “masting” (what is it? why do it?), pinyon jay co-evolution
pinyon mortality over last few years
fire ecology
grazing impacts: are all grasslands equally adapted to grazing?
grazing-exotic grasses-fire cycle…: feedbacks/concept map diagram
dominant species at different elevations
phreatophytes
importance to wildlife
3 different flood types caused by 3 different precipitation events
dependence of cottonwood on stream dynamics
stream meanders, erosion, cottonwood seedlings on point bars
stream systems – natural dynamics & floods; geomorphology & landscape features
impact of dams – change in disturbance regime
invasion of exotic species (what are they?)
relationships among all these variables
General:
· Beast in the Garden questions (from hand-outs & discussions)
· Readings: assigned articles & Leopold essays = good fodder for questions
· Animal presentations: choose 3 of the animals presented by you & your classmates, be able to tell which habitat they prefer & give one piece of interesting biological/ecological information about each species' interaction with another species (or environmental factor)
These will be short answer questions, but the “interesting facts” you choose to convey need to show some depth of understanding, and an appreciation for connections.
Hot Deserts
environment
adaptations of desert plants & animals
drought escaping, drought avoiding (evading), drought resisting
give examples of each
Chihuahuan Desert – location (e.g. a Park you could visit), climate,
dominant & indicator plants (agaves) & animals (zonetail hawk)
Mojave Desert - location (e.g. a Park or place you could visit), climate,
dominant & indicator plants (big, “tree” yuccas) & animals
Sonoran Desert - location (e.g. a Park or place could visit), climate,
dominant & indicator plants (cacti) & animals;
importance of saguaro cactus as keystone species
desert plants: biology, interactions & human uses
species we discussed in lab (organpipe cactus, mescal (agave),
creosote, mesquite) (Lab week after exam)