Biogeography of Xanthoria Lichens of the Farlow Herbarium; Maine

							(Written by Anne Pringle with help from Benjamin Wolfe, Primrose Boynton, and
Donald Pfister. Please adapt as useful! I think it’s self-explanatory, but email Anne
at pringle@oeb.harvard.edu if you have questions.)

OEB 54 – Lichen Biogeography Lab
Biogeography of Lichens of the Boston Harbor Islands, from the Farlow Herbarium
November 2, 2010

Introduction:
We’ve spent time talking about some classic biogeographic patterns, and whether they are
useful for fungi. One example is the latitudinal gradient in species diversity; species richness
is expected to increase as one travels from the poles to the equator. That pattern seems to
work for birds and other animals, as well as plants, but may or may not work for various
groups of fungi. Another is the species-area curve; species richness increases with increasing
area. That pattern should work for fungi, but does it?

You will build a graph of species numbers and area using dried specimens housed at the
Farlow Herbarium of Harvard. For simplicity we will focus on a small geographic area; we
will be cataloguing specimens of lichens collected from the Boston Harbor Islands. You may
work individually, or in small groups.

Instructions:
A map of the islands is attached to this lab. Go through the collections and in a systematic
fashion (i.e. don’t look at the same specimen twice!) take notes on the genus and species
names and the islands from which species were collected. Once you’ve found a species from
an island, you don’t need to record it a second time, i.e. if you find Xanthoria elegans from
Spectacle Island you don’t need to look at additional collections of Xanthoria elegans from
Spectacle Island. Work until you’ve exhausted the collection. Aim to work through about
two boxes of specimens each.

Type your data into a spreadsheet and e-mail this to Primrose
(pboynton@fas.harvard.edu) by 5pm tomorrow (Wednesday, November 3rd). For the
homework you’ll need all data produced by the entire class. Homework is due
Tuesday, November 9th in class.

Homework:
  1. On average, how many species do you find per acre? (see next page for listing of
     total area of each island)
         a. Is this average different for large and small islands?
         b. Does it make a difference where that island is in the harbor?

    2. Plot number of species found against area. There are many ways to make this plot:
       you could consider individual islands, random sums of areas, or other definitions of
       areas. Explain in a few sentences why you chose to build your plot the way you did.

    3. What kind of relationship do you see? Did you find a species-area curve? Why or
       why not?
    4. Compare this plot with a plot of number of islands on the x-axis and average
         number of species (and error bars!) on the y-axis. Did you find a species-area curve
         here? Why or why not?
Please limit your answers to one or two pages total.
Total Area of Boston Harbor Islands (in acres):

Island Name                     Total Acres
Nixes Mate                      0
Shag Rocks                      1.3
The Graves                      1.8
Snake                           3
Sheep                           3.2
Raccoon                         3.6
Ragged                          4.1
Sarah                           4.6
Hangman                         6
Little Brewster                 7
Langlee                         8
Slate                           12.7
Middle Brewster                 13.6
Green                           17
Outer Brewster                  20.1
Nut                             20.5
Rainsford                       21.6
Calf                            35
Webb Memorial Park              36
Moon                            45.7
Gallops                         50
Georges                         53
Lovells                         61.9
Bumpkin                         62
Great Brewster                  68
Grape                           101
Spectacle                       114
Button                          116
Thompson                        169.9
Peddocks                        210.4
Long                            225.2
Deer                            265
Worlds End                      274.3
Little Calf                     NA