The Sixth Extinction: An Unnatural History

realize “that you are standing”: Barry Lopez, Arctic Dreams (1986; reprint, New York:
Vintage, 2001), 29.
Massachusetts around fifty-five: Gordon P. DeWolf, Native and Naturalized Trees of
Massachusetts (Amherst: Cooperative Extension Service, University of Massachusetts, 1978).
though not, interestingly enough, for aphids: John Whitfield, In the Beat of a Heart: Life,
Energy, and the Unity of Nature (Washington, D.C.: National Academies Press, 2006), 212.
“a spectacle as varied”: Alexander von Humboldt and Aimé Bonpland, Essay on the Geography
of Plants, edited by Stephen T. Jackson, translated by Sylvie Romanowski (Chicago: University of
Chicago Press, 2008), 75.
“The verdant carpet”: Alexander von Humboldt, Views of Nature, or, Contemplations on the
Sublime Phenomena of Creation with Scientific Illustrations, translated by Elsie C. Otté and Henry
George Bohn (London: H. G. Bohn, 1850), 213–17.
One theory holds: Many theories of the latitudinal diversity gradient are summarized in Gary
G. Mittelbach et al., “Evolution and the Latitudinal Diversity Gradient: Speciation, Extinction and
Biogeography,” Ecology Letters 10 (2007): 315–31.
A famous paper: Daniel H. Janzen, “Why Mountain Passes Are Higher in the Tropics,” American
Naturalist 101 (1967): 233–49.
“evolution has had a fair chance”: Alfred R. Wallace, Tropical Nature and Other Essays
(London: Macmillan, 1878), 123.
Trees in Schefflera: Kenneth J. Feeley et al., “Upslope Migration of Andean Trees,” Journal of
Biogeography 38 (2011): 783–91.
“some of the most acute and powerful intellects”: Alfred R. Wallace, The Wonderful Century:
Its Successes and Its Failures (New York: Dodd, Mead, 1898), 130.
“As the cold came on”: Darwin, On the Origin of Species, 366–67.
the Andes are expected: Rocío Urrutia and Mathias Vuille, “Climate Change Projections for
the Tropical Andes Using a Regional Climate Model: Temperature and Precipitation Simulations
for the End of the 21st Century,” Journal of Geophysical Research 114 (2009).
I’d recently read a paper: Alessandro Catenazzi et al., “Batrachochytrium dendrobatidis and the
Collapse of Anuran Species Richness and Abundance in the Upper Manú National Park,
Southeastern Peru,” Conservation Biology 25 (2011): 382–91.
“Here’s another way to express”: Anthony D. Barnosky, Heatstroke: Nature in an Age of Global
Warming (Washington, D.C.: Island Press/Shearwater Books, 2009), 55–56.
The study ran as the cover article: Chris D. Thomas et al., “Extinction Risk from Climate
Change,” Nature 427 (2004): 145–48.
Thomas suggested that it would be useful: Chris Thomas, “First Estimates of Extinction Risk
from Climate Change,” in Saving a Million Species: Extinction Risk from Climate Change, edited by Lee
Jay Hannah (Washington, D.C.; Island Press, 2012), 17–18.