error (for example, in Kellert, 1993, pp. 43, 44, 58, 60). Ambitious
speculations are not demonstrated fact.
No one should discount that some individuals feel a deep emotional rapport with nature and value its preservation. Many (myself
among them) stand in awe of nature. Scientists should certainly
study how that attitude emerges, how it is learned, and how it can
be nurtured (Keltner & Haidt, 2003). That might help us achieve
the “reenchantment” that Wilson sees as critical to conservation
(1984, p. 139; Mackenzie, 2008). But that does not warrant an idea
of innate biophilia (recently assumed by a Sierra Club program, for
example; Abrahamson, 2014).
The Very Term “Biodiversity”
The companion concept to biophilia is biodiversity. It, too, has a history. Public efforts to conserve nature have a long heritage, reflected,
for example, in the establishment of Yellowstone as the first national
park in the United States in 1872, and of the private Lüneburg Heath
Nature Reserve in Germany in 1921. But specific attention to preserving species emerged later, notably in the landmark Endangered
Species Act of 1973. The shift in focus crystallized in a National
Research Council conference in 1986. That meeting helped identify
the promotion of the value of biological diversity as an explicit goal.
The label quickly became shortened to the glitzy sounding “
biodiversity,” a term that entered the scientific literature between 1988 and
1993 (Franco, 2013; Takacs, 1996, pp. 34–40).
“Biodiversity” was never intended as a neutral term. It did not
just describe the collected variation in species. It embodied the
ethos of many biologists who adopted it to express their environ-
mental values: to protect and preserve those species. That posture
of hybridizing science and values was common in conservation
biology, which coalesced as a discipline in the 1980s. The new field
was distinctive in attracting scientists who linked their research to
explicit ideological goals, and often to political advocacy. As a term,
“biodiversity” was always meant to convey a value of conservation.
“Biodiversity shines with the gloss of scientific respectability, while
underneath it is kaleidoscopic and all encompassing” of many
values and interpretations (Takacs, 1996, pp. 34–99, quote on
p. 99). For example, Wilson linked his concept of biophilia to
advocacy for biodiversity, what he characterized as “the most harm-
ful part of ongoing environmental despoliation” (1993, pp. 35–39).
Scientists continue to try to establish an “objective” value of biodi-
versity. In a recent review, noted ecologist David Tilman and col-
leagues underscored the causal links between biodiversity and
ecosystem functioning (Tilman et al., 2014). Decades of experimen-
tal ecology have demonstrated that a higher number of species
leads to (and is not merely correlated with) an increase in several
key ecosystem variables (Figure 1). First, diverse ecosystems exhibit
greater primary productivity. That is, they convert up to twice as
much solar energy into raw biomass. When species are comple-
mentary, it seems, an ensemble can use limiting resources more
fully. Second, diverse communities are more stable through stress-
ful conditions, such as drought, fire, excess nitrogen deposits, or
herbivory. They are also more resilient to invasion by new species.
Finally, diverse ecosystems promote nutrient cycling and storage,
further amplifying the effects in the long term. Species diversity
as a variable certainly matters to ecosystems. But that fact was
transformed into a value in drawing the final lesson: “the preserva-
tion, conservation and restoration of biodiversity should be a high
global priority.” While these studies certainly document the effect of
species diversity, they do not thereby justify any ultimate value.
Productivity and stability as outcomes have no inherent ethical
value themselves. Ultimately, the biodiversity label conveys a per-
sonal value, not a scientifically justified ethical principle.
Indeed, appeals to biodiversity raise the question of why counting
species seems to upstage the more general principle of “respect for life.”
In the politics of biodiversity and biophilia, scientific and ethical
modes of justification become muddled, eroding the integrity of the
Figure 1. Long-term, large-scale experiments at Cedar Creek
Ecological Reserve in Minnesota have helped demonstrate that
increasing the number of species has positive effects on
ecosystem productivity, stability, nutrient storage, and resilience
to invasion. But do such scientific studies justify biodiversity as
an objective value? (Usage of this image does not constitute
endorsement by Cedar Creek Ecosystem Science Reserve or the
University of Minnesota.)