Diverse Ecosystem Dynamics: From Fig Trees to Finches

1. Fig - Fig Wasp Natural History 750 spp. of fig, most with a single sp. of pollinator!! http://129.31.3.171/index.html

2. Fig - Fig Wasp Model MVP: ~ 170 fig trees are required to eliminate a gap in flowering among trees - i.e., 99% probability of persistence for 1000 years.

3. Big-Blue ButterflyAn obligate parasite of ant colonies Butterfly oviposits on thyme Caterpillar becomes a beautiful butterfly Caterpillar feeds on thyme Caterpillar is fed by / feeds on ants Caterpillar enters Myrmica ant nest http://faculty.plattsburgh.edu/thomas.wolosz/metapop.htm

4. Big-Blue Butterfly • First started disappearing in the 19th century • Hypotheses • Over-collecting by insect collectors • Insecticides • Fragmentation • Climate change • Air pollution • Rapid decline in the 1950’s, extinct by 1979.

5. Big-Blue Butterfly THYME BUTTERFLY SHORT GRASSY FIELDS ANTCOLONY (Myrmica sabuleti) GRAZING MYXOMATOSIS RABBITS

6. Migratory Birds • Studies have identified a decrease in U.S. neotropical migrants • Decreasing at the rate of 0.5 to 1.0% per year • Hypotheses • Deforestation in tropics or breeding ground • Susceptibility to predation or cowbird parasitism on breeding grounds

7. Brown-headed cowbird

8. The Evidence • Based on taxonomically diverse community in eastern U.S. • Decline of migrants equal to ~ 1% / year. • Based on wood warblers, vireos, gnatcatchers, kinglets, titmice, chickadees, nuthatches, brown creeper, wrens, bluebirds across U.S. • No decline for migrants • Recent declines in birds with high susceptibility to predation / cowbird parasitism

9. Black-Footed FerretThe most endangered mammal in N. America http://www.ngpc.state.ne.us/wildlife/ferret.html

10. Inter-relationship of species “The number of bumblebees in any district depends in a great measure upon the number of field-mice, which destroy their combs and nests”. “[Because] the number of mice is largely dependent, as everyone knows, on the number of cats . . . It is quite credible that the presence of a feline animal in large numbers in a district might determine, through the intervention first of mice and then of bees, the frequency of certain flowers in that district!” - Charles Darwin, On the Origin of Species

11. Photo by James M. Cook Keystone Species

12. Keystone Species Species with a disproportionate effect on community structure. Keystones Dominants strong interactors Total Effect weak interactors Common Cold Abundance From: Meffe and Carroll

13. Problems with the Keystone Species Concept • Loosely applied • Difficult to test • Questionable application • Conclusion: Focus on interaction strengths

14. Ecological Niche • Grinnell (1917): where a species lives (habitat) • Elton (1927): what a species does • Hutchinson (1950s): combination of all biotic and abiotic requirements of a species: n-dimensional “hyper-volume” abundance temperature seed size predator density

15. Competitive Exclusion • If the niches of two competing species overlap by “too much”, then one tends to replace the other. • Corollary: Competition drives the evolution of divergent niches or life-history strategies (i.e., respond or perish) abundance abundance niche niche

16. Darwin’s Finches:Character Displacement

17. “The Ghost of Competition / Predation Past” • What we see today may be the result of competition / predation in the past (i.e., implies evolutionary history). • Consider Pleistocene extinctions • Conservation Implication: Exotic species may have their most negative effects after invading communities that lack an analogous evolutionary partner