Lecture 11: Putting things together:Species interactions in subalpine meadows
• Erythronium grandiflorum (glacier lily)(zoom in)
o Observed the most where the soil surface is very rocky.
o Half part of the plant grows in the soil, during most of the time,all parts
are underground, grows up when flowering.
o Nutrients stored in the bulbs.
Primary seed dispersal distanceexperiment
• Mark seeds in fruits with fluorescent powders, lay out fabric sprayed with
• Result: dispersal distance about 20cm; pathetic!
• Glacier lily does not have elaiosome.
o Doesn’t have anything to do with growth, extremely nutritious, attracts antsàprovide a
Seed germination experiments
• Plant the seed in 4 treatment combination:
o Buried, organic soilà live!
o Exposed, organic soilàdied!
o Buried, gravel soilàdied!
o Exposed, gravel soilàdied!
• Long-lived, iteroparous; grows as a“vegetative” plants for years before flowering.
o At least 6-7 years to grow
• Resource storage organ is underground corm
• Seeds subject to desiccation unless in moist conditions
• Seed dispersal distance minimal
What do the experiments suggest about distribution?
• Desiccation: should find more plants on the deep soil, less plant on the shallow soil (but we see
• Weak dispersal: should find mostseeding near flowering plants (expect to find those)
• Need to gather quantitative date on plant abundance andenvironmental factors
Set up study plot, 16X16 grid of 2X2m squares; measure variables in eachsquare; make maps
• Factors measuring
o Flowering plants (count)
o Vegetative plants (count)
o Seedlings (subsample)
o Soil moisture
o Predation risk
§ Attacked underground by pocket gopher; eat corm
§ Digging specialist; claws and teeth
§ Huge cheek pouches to store food
• Quantified by the amount of soil they pushed up to make tunnel Results:
• Number of flowers vs. number of vegetative plants
o Living in the same area, makes sense
• Number of flowers vs. numbers of seedling
o No correlation between the two.
o Not as expected.
• Rockiness vs. soil moisture
o Rockiness and moisture are inversely related
o Seedling is located in the moist a