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Ecological Economics 55 (2005) 5 – 10
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COMMENTARY
The importance of sound biological information and theory for
ecological economics studies valuing Brazilian biodiversity:
A response to Mendonça et al. (2003)
Daniel Brito *
Graduate Program in Ecology, Conservation and Wildlife Management (ECMVS), Institute of Biological Sciences,
Federal University of Minas Gerias, Avenida Antônio Carlos 6627, Belo Horizonte, MG 31270-901, Brazil
Received 30 December 2003; accepted 5 May 2005
Available online 19 August 2005
Abstract
Biodiversity valuation is a controversial issue. Mendonça et al. (2003) [Mendonça, M.J.C., Sachsida, A., Loureiro, P.R.A.,
2003. A study on the valuing of biodiversity: the case of three endangered species in Brazil. Ecological Economics 46, 9–18] use
data from published results of population viability analyses (PVAs) coupled with taxonomic information based on a methodology
proposed by Montgomery et al. (1999) [Montgomery, C.A., Pollak, R.A., Freemark, K., White, D., 1999. Pricing biodiversity.
Journal of Environmental Economics and Management 38, 1–19] to estimate the management price of three mammal species from
Brazil: the golden lion tamarin (Leontopithecus rosalia), the black lion tamarin (Leontopithecus chrysopygus) and the long-furred
woolly mouse opossum (Micoureus travassosi). However, there are several inconsistencies in the information given by Mendonça
et al. (2003) and articles from which they based their analyses. Mendonça et al. (2003) misunderstand metapopulation and
extinction concepts, wrongfully interpret PVAs results, and show a lack of knowledge on mammalian taxonomy and systematics.
These data are cornerstones for their analyses. Therefore, the results presented by Mendonça et al. (2003) should be viewed with
caution. Despite being a controversial issue, ecological economics studies will only give reliable results and management insights
if they rely on sound biological information. The lack of biological knowledge and the lack of interaction with biologists may
invalidate results, and worst of all, if not detected, they may lead to dissemination of wrong information, mislead management
strategies and lead to catastrophic consequences for biodiversity. Biodiversity conservation is part of an economic world, and I
praise Mendonça et al. (2003) for trying to merge technical biological information to economic studies of biodiversity valuation,
but sound scientific information from biological sciences is of paramount importance for the development of such multidisciplinary approaches, and the sources of such information should be biologists, not economists. For such analyses to have any
chance to succeed, a collaboration of both economists and biologists is necessary.
D 2005 Elsevier B.V. All rights reserved.
Keywords: Biodiversity; Conservation biology; Contingent valuation; Population viability analysis
* Present address: Rua Andrade Neves 93/802, Rio de Janeiro, RJ 20510-230, Brazil.
E-mail address: [email protected].
0921-8009/$ - see front matter D 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.ecolecon.2005.05.009
6
D. Brito / Ecological Economics 55 (2005) 5–10
1. Introduction
Mendonça et al. (2003) present an analysis establishing the bound limits to the management price of
three species in Brazil: the black lion tamarin Leontopithecus chrysopygus, the golden lion tamarin Leontopithecus rosalia, and the long-furred woolly mouse
opossum Micoureus travassosi. Mendonça et al.
(2003) took into account estimates of likelihood of
extinction through population viability analysis (PVA)
(Brito and Fernandez, 2000a) to estimate how much
the household would be willing to pay to finance a
conservation program for these species. Brazil is a
megadiversity country, with two biodiversity hotspots
(Myers et al., 2000) and two wilderness areas (Mittermeier et al., 2003) within its borders, but the lack of
information on Brazilian fauna and flora is still surprising. I praise Mendonça et al. (2003) for trying to
merge biological data from PVA into ecological economics analysis. However, there are several points
concerning biological information and theory that
may weaken the analysis and the results found by
the authors, which I will deal with in the following
sections. Sound biological theory and information are
of paramount importance to such analysis.
2. Metapopulation theory
Mendonça et al. (2003) define metapopulation as:
ba population of a certain species that is restricted to a
specific area, as opposed to the population as a
wholeQ. However, this is not the concept of metapopulation that biologists adopt (Hanski and Gilpin,
1991; McCullough, 1996; Hanski and Simberloff,
1997; Hanski, 1999; Brito and Fernandez, 2000a).
Hanski and Gilpin (1991) defined a set of key metapopulation terms in the hope of promoting a more
uniform terminology, which was updated by Hanski
and Simberloff (1997), where metapopulation is defined as: bset of local populations within some larger
area, where typically migration from one local population to at least some other patches is possibleQ.
A metapopulation is discontinuous in distribution.
It is distributed over spatially disjunct patches of
suitable habitat separated by a matrix of unsuitable
habitat in which animals cannot survive (McCullough,
1996). Because of the risk of mortality in crossing
hostile conditions of the matrix, movement between
populations is not routine. Consequently, dispersal is
restricted. Furthermore, because many of the habitat
patches may be small, consequently supporting small
population sizes, extinction in given patches (local
extinction) may be a common event compared to
extinction of continuous populations (McCullough,
1996). A metapopulation’s persistence depends on
the combined dynamics of extinction within given
patches and recolonization among patches by dispersal. So long as the rate of colonization exceeds the rate
of extinction, the metapopulation can persist even
though no given population in a patch may survive
continuously over time (McCullough, 1996).
3. Extinction
Mendonça et al. (2003) state: ba local extinction is
also a global one since observations from islands
would suggest that reductions in continuous areas
and isolation of habitats would increase the rate of
extinctionQ. Mendonça et al. (2003) misunderstand the
concepts of local and global extinction in their statement. Local extinction occurs when the last individual
of a particular population of a given species dies. In
most cases, this does not imply disappearance of the
whole species, as other populations survive elsewhere
(Brito and Fernandez, 2000a). Extinction of the last
local population, however, is global extinction, because there are no other extant populations anywhere
and the species is extirpated from nature (Brito and
Fernandez, 2000a).
4. Brazilian population viability analysis case
studies
In Brazil, PVAs had already been used to evaluate
status and suggest management options for L. rosalia
(Kierulff, 1993), L. chrysopygus (Valladares-Pádua et
al., 1994), M. travassosi (Brito and Fernandez, 2000b,
2002; Brito, 2002; Brito and Grelle, 2004), Brachyteles arachnoides (Strier, 2000) and Trinomys eliasi
(Brito and Figueiredo, 2003). M. travassosi was previously named Micoureus demerarae, but a recent
taxonomic revision on the genus Micoureus concluded that the populations from southeastern Brazil actu-
D. Brito / Ecological Economics 55 (2005) 5–10
ally belonged to a separate species, named M. travassosi whereas M. demerarae is found in Amazonia and
the northeastern Atlantic Forest (Costa, 2003). Such
revision indicates that the taxa studied by Brito and
Fernandez (2000b) should be named from now on as
M. travassosi.
Mendonça et al. (2003) say that M. travassosi is
one of the most endangered species in the Atlantic
Forest. This is wrong. M. travassosi is listed as
endangered neither by IUCN’s red list (Hilton-Taylor, 2000), nor by the Brazilian red list (MMA,
2003). Brito and Fernandez (2000b) studied a metapopulation found at a set of small Atlantic Forest
fragments, known as the howler monkeys’ islands
(ilhas dos barbados), located at the southern region
of Poço das Antas Biological Reserve. Therefore the
estimates of likelihood of extinction made by Brito
and Fernandez (2000b) apply to the howler
monkeys’ islands metapopulation only. The misunderstanding definitions of metapopulation and extinction used by Mendonça et al. (2003), and the lack of
sound ecological theory and information led the
authors to false statements, results, and conclusions
regarding their analysis of M. travassosi status. The
species M. travassosi is not endangered (Hilton-Taylor, 2000; MMA, 2003), but one metapopulation of
M. travassosi located at the howler monkeys’ islands
is (Brito and Fernandez, 2000b). Mendonça et al.
(2003) state that the probability of the species M.
travassosi becoming extinct in the next 100 years is
of approximately 45%. However, the results and data
presented by Brito and Fernandez (2000b) clearly
show that the metapopulation of M. travassosi located at the howler monkeys’ islands is endangered
and that its probability of extinction under current
conditions is of approximately 99%, and not 45% as
shown by Mendonça et al. (2003). Brito and Fernandez (2000b) clearly state they are analyzing the
howler monkeys’ islands metapopulation of M. travassosi and not the species as a whole.
Regarding L. rosalia, Mendonça et al. (2003) state
that the PVA research was conducted based on the
metapopulations located at the Poço das Antas Biological Reserve. Again, they misunderstand population and metapopulation concepts. Poço das Antas
Biological Reserve has a population of L. rosalia,
which is part of a metapopulation found at Rio de
Janeiro state (Kierulff, 1993). Therefore, the 15%
7
likelihood of extinction refers to the population of
Poço das Antas Biological Reserve, and not to the
metapopulation located in the region.
Mendonça et al. (2003) say that the probability of
the metapopulation of L. chrysopygus going extinct in
the next 10 years was estimated as 78%. However,
Seal et al. (1990) show results for the populations of
L. chrysopygus located at Morro do Diabo and Caitetus. There is no information about metapopulation
extinction, but likelihood of extinction in 10 years for
both populations is given: around 78% for Caitetus’
population and less than 10% for Morro do Diabo’s
population.
Mendonça et al. (2003) state that information regarding the changes in population viability resulting
from a variation in the size of a species is an important
parameter to their model. And they use information
given in PVA studies from M. travassosi (Brito and
Fernandez, 2000b), L. chrysopygus (Seal et al., 1990)
and L. rosalia (Kierulff, 1993) to model optimistic
and pessimistic scenarios regarding population persistence. However, the parameters used to model optimistic and pessimistic scenarios for M. travassosi
populations did not include variation in the initial
population size (Brito and Fernandez, 2000b). Brito
and Fernandez (2000b) made sensitivity analysis for
the following parameters: (1) level of inbreeding depression, (2) probability of catastrophe (fire), (3) carrying capacity, (4) migration rate, (5) mortality rate,
and (6) sex ratio. Brito and Fernandez (2000b) did not
evaluate sensitivity to changes in initial population
size, which is the parameter Mendonça et al. (2003)
use to model their scenarios. They most probably
misinterpreted information given in Brito and Fernandez (2000b). Mendonça et al. (2003) show viability
estimates for different scenarios in Table 1. As mentioned above, it is impossible to know from where
came the estimates of optimistic and pessimistic scenarios for M. travassosi since the original article did
not evaluate this parameter (Brito and Fernandez,
2000b). Mendonça et al. (2003) say that M. travassosi
has a probability of persistence of 0.55 in the base
scenario. However, information given in Mendonça et
al.’s (2003) Table 1 is not in accordance with the
results presented by Brito and Fernandez (2000b),
where the likelihood of persistence for the basic scenario is 0.01. Therefore the accuracy of the estimate of
variation in viability DV for M. travassosi, which is an
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D. Brito / Ecological Economics 55 (2005) 5–10
important parameter to Mendonça et al.’s (2003)
model, is doubtful.
5. Taxonomic information
Mendonça et al. (2003) adopt the methodology for
measuring biodiversity presented by Montgomery et
al. (1999). This measurement utilizes the weight of
diversity obtained from the taxonomic tree of each
species. Instead of searching for taxonomic information on Brazilian mammals in the internet, the authors
should look after biologists and taxonomists for reliable knowledge and information on this topic. Mendonça et al. (2003) calculate the degree of diversity for
M. travassosi saying this species belongs to the genus
Didelphimorphia. This statement makes clear the lack
of taxonomic knowledge by Mendonça et al. (2003).
The rules of biological nomenclature state that every
species name is composed of two words, the first one
is the name of the genus the species belongs to and the
second one is the specific name. Therefore the information regarding the genus to which M. travassosi
belongs to is contained in the very name of the
species: Micoureus. Besides that, every biologist
with a minimal knowledge on mammalian zoology
knows that Didelphimorphia is a mammal order, a
greater level in the taxonomic hierarchy. If Mendonça
et al. (2003) based their calculations of weight of
diversity on such wrong information about the taxonomic tree of M. travassosi, their results for the
management price for this species are not reliable. A
simple cooperation among biologists and economists
would have avoided such problems.
6. Biodiversity valuation: a controversial issue
Many, if not most, extinctions have a critical, if not
causative, economic rationale (Caughley and Gunn,
1996; Pearce and Moran, 1998; Bulte and Van Kooten, 2000; Czech et al., 2000; Naidoo and Adamowicz, 2001). Few problems in economics are more
complex than making choices in the context of biodiversity and no economist would argue that the problem is resolved (Pearce and Moran, 1998). The
economic importance of biodiversity relates to its
direct and indirect effect on human well-being or
welfare. Welfare can be inferred from the money
people are observed to pay in actual markets, or
their stated willingness to pay, in hypothetical markets. It is this willingness to pay that provides the
handle for the economic analysis of biodiversity loss
(Pearce and Moran, 1998). In this process, called
contingent valuation, people are asked how much
they would be willing to pay to protect species quite
independent of any use of that species (Dobson,
2000). Unfortunately, surveys of this sort indicate
that the amount people are willing to pay to conserve
a specific species declines as we move from mammals
and birds to plants and invertebrates (Dobson, 2000).
Besides that, contingent valuation is an efficiencybased value based on a model of human behavior
sometimes referred to as bHomo economicusQ, that
humans act rationally and in their own self-interest
(Costanza, 1997). Value in this context is based on
current individual preferences that are fixed or given.
Little discussion or scientific input is required to form
these preferences, and value is simply people’s
revealed willingness to pay for the good or service
in question (Costanza, 1997). Although economic
analysis can be used to argue for preservation of
species and habitats, many natural assets represent
inferior investments in society’s asset portfolio
(Bulte and Van Kooten, 2000). O’Neill and Walsh
(2000) evaluated the effectiveness of contingent valuation as a way to solve landscape conflicts, and
concluded that such an approach is flawed. Landscape
conflicts involve issues of identity that cannot be
captured in terms of preference satisfaction and conflict of perceived rights which could not in principle
be resolved by cost-benefit analysis (O’Neill and
Walsh, 2000). Few studies have analyzed species
endangerment explicitly in terms of economic scale
and sectors, and they suggest that national and international goals of economic growth and biodiversity
conservation are conflicting (Czech et al., 2000; Naidoo and Adamowicz, 2001). However, policymakers
throughout the world have denied that this conflict
exists, claiming instead that economic growth and
biodiversity conservation may be reconciled via technological progress (Czech, 2003).
Many economists believe that the reasons for caring
about biodiversity are instrumental and utilitarian
(Randall, 1991). According to Given (1994), instrumental reasons for preserving species are of two kinds:
D. Brito / Ecological Economics 55 (2005) 5–10
(1) organisms possess direct economic value as
resources for humanity, both now and in the future;
and (2) species provide goods and services indirectly.
There are economists who suggest that although valuation is certainly difficult, one choice we do not have is
whether or not to do it (Costanza, 1997). Although
ecologists increasingly attempt to justify preservation
of biological assets on economic grounds (e.g. Balmford et al., 2002), this might be a dangerous approach
to take, and there are biologists who question economic arguments for protecting species (Sagoff, 1997;
Bulte and Van Kooten, 2000). Equating the consequences of biodiversity loss with money-equivalent
loss of human well-being is a highly anthropocentric
view of the world. Ehrenfeld (1988) argues that owing
to changes in our needs and in our technology, instrumental approaches to valuation are shifting, fluid, and
utterly opportunistic in their practical application. This
is the opposite of the value system necessary to conserve biological diversity over the course of decades
and centuries (Sagoff, 1997). Dworkin (1994) points
out that most of us attribute intrinsic value to other
species and we should admire and protect them because they are important in themselves, and not because we, or others want or enjoy them. While
conservation biologists are plainly moved by the
same spiritual, aesthetic, and cultural commitments
to save species that motivate society as a whole,
many lack the courage of their ethical convictions
and instead offer economic or instrumental arguments
for preserving biodiversity (Sagoff, 1997). In so doing,
they support the economist’s credo that it is irrational
to value anything but our own well-being and, therefore, that we should protect species not because they
are intrinsically valuable or deserve our respect, nor
because of religious, moral or cultural beliefs, but on
economic grounds, insofar as species contribute to our
well-being or welfare (Sagoff, 1997). In this way they
validate the view that only one kind of value is important, instrumental value for human well-being, and
thus they protect not nature, but the very economic
framework and perspective most likely to undermine it
(Sagoff, 1997). As Leakey and Lewin (1996) state:
becologists have largely allowed economists to set the
terms of the debate over the value of biodiversity. The
danger is that, having accepted the invitation to enter
the lion’s den, they are likely to end up as the lion’s
dinnerQ. Not surprisingly, biodiversity valuation is a
9
subject of considerable controversy (Caughley and
Gunn, 1996, Leakey and Lewin, 1996; Costanza,
1997; Sagoff, 1997; Pearce and Moran, 1998; Bulte
and Van Kooten, 2000; Dobson, 2000).
Acknowledgments
I thank the support from Fundação Biodiversitas
and the US Fish and Wildlife Service. This article is
one of the results of a PhD scholarship from FAPEMIG given to Daniel Brito.
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