Federal Register: August 12, 2009 (Volume 74, Number 154)
DOCID: fr12au09-28 FR Doc E9-18691
DEPARTMENT OF THE INTERIOR
U.S. Customs and Border Protection
CFR Citation: 50 CFR Part 17
RIN ID: RIN 1018-AV74
FWS ID: [FWS-R9-IA-2009-0028; 96100-1671-0000-B6]
NOTICE: Part II
DOCID: fr12au09-28
DOCUMENT ACTION: Proposed rule.
SUBJECT CATEGORY:
Endangered and Threatened Wildlife and Plants; Listing Seven Brazilian Bird Species as Endangered Throughout Their Range
DATES: We will accept comments received or postmarked on or before October 13, 2009. We must receive requests for public hearings, in writing, at the address shown in the FOR FURTHER INFORMATION CONTACT section by September 28, 2009.
DOCUMENT SUMMARY:
We, the U.S. Fish and Wildlife Service (Service), propose to list the following seven Brazilian bird species and subspecies (collectively referred to as ``species'' for purposes of this proposed rule) as endangered under the Endangered Species Act of 1973, as amended (Act) (16 U.S.C. 1531 et seq.): blackhooded antwren (Formicivora erythronotos), Brazilian merganser (Mergus octosetaceus), cherrythroated tanager (Nemosia rourei), fringebacked fireeye (Pyriglena atra), Kaempfer's todytyrant (Hemitriccus kaempferi), Margaretta's hermit (Phaethornis malaris margarettae), and southeastern rufousvented groundcuckoo (Neomorphus geoffroyi dulcis). This proposal, if made final, would extend the Act's protection to these species. The Service seeks data and comments from the public on this proposed rule.
SUMMARY:
Interior Department, Fish and Wildlife Service
SUPPLEMENTAL INFORMATION
Public Comments
We intend that any final action resulting from this proposal will
be as accurate and as effective as possible. Therefore, we request
comments or suggestions on this proposed rule. We particularly seek comments concerning:
(1) Biological, commercial trade, or other relevant data concerning
any threats (or lack thereof) to these species and regulations that may be addressing those threats.
(2) Additional information concerning the taxonomy, range,
distribution, and population size of these species, including the locations of any additional populations of these species.
(3) Any information on the biological or ecological requirements of these species.
(4) Current or planned activities in the areas occupied by these
species and possible impacts of these activities on these species.
(5) Any information concerning the effects of climate change on these species or their habitats.
You may submit your comments and materials concerning this proposed rule by one of the methods listed in the ADDRESSES section. We will not consider comments sent by email or fax or to an address not listed in the ADDRESSES section.
If you submit a comment via http://www.regulations.gov, your entire commentincluding any personal identifying informationwill be posted on the Web site. If you submit a hardcopy comment that includes personal identifying information, you may request at the top of your document that we withhold this information from public review. However, we cannot guarantee that we will be able to do so. We will post all hardcopy comments on http://www.regulations.gov.
Comments and materials we receive, as well as supporting documentation we used in preparing this proposed rule, will be available for public inspection on http://www.regulations.gov, or by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Endangered Species Program, 4401 N. Fairfax Drive, Room 420, Arlington, VA 22203; telephone 7033582171.
Background
Section 4(b)(3)(A) of the Act requires us to make a finding (known as a ``90day finding'') on whether a petition to add a species to, remove a species from, or reclassify a species on the Federal Lists of Endangered and Threatened Wildlife and Plants has presented substantial information indicating that the requested action may be warranted. To the maximum extent practicable, the finding must be made within 90 days following receipt of the petition and must be published promptly in the Federal Register. If we find that the petition has presented substantial information indicating that the requested action may be warranted (a positive finding), section 4(b)(3)(A) of the Act requires us to commence a status review of the species if one has not already been initiated under our internal candidate assessment process. In addition, section 4(b)(3)(B) of the Act requires us to make a finding within 12 months following receipt of the petition (``12month finding'') on whether the requested action is warranted, not warranted, or warranted but precluded by higher priority listing. Section 4(b)(3)(C) of the Act requires that a finding of warranted but precluded for petitioned species should be treated as having been resubmitted on the date of the warranted but precluded finding, and is, therefore, subject to a new finding within 1 year and subsequently thereafter until we publish a proposal to list or a finding that the petitioned action is not warranted. The Service publishes an annual notice of resubmitted petition findings (annual notice) for all foreign species for which listings were previously found to be warranted but precluded.
The following seven Brazilian bird species are addressed in this proposed rule: Blackhooded antwren (Formicivora erythronotos), previously recognized under the genus Myrmotherula; Brazilian merganser (Mergus octosetaceus); cherrythroated tanager (Nemosia rourei); fringebacked fireeye (Pyriglena atra), previously referred to as Swainson's fireeye; Kaempfer's todytyrant (Hemitriccus kaempferi), previously recognized under the genus Idioptilon; Margaretta's hermit (Phaethornis malaris margarettae), previously referred to as the Klabin Farm longtailed hermit and recognized at the species level as P. margarettae; and southeastern rufousvented groundcuckoo (Neomorphus geoffroyi dulcis). All of the above species are found in the Atlantic Forest and neighboring regions of southeastern Brazil.
[[Page 40651]]
We are addressing the seven Brazilian bird species identified above under a single proposed rule primarily for three reasons. First, all of these species are found in the Atlantic Forest and neighboring regions of southeastern Brazil, thus addressing them together makes sense from a regional conservation perspective. Second, these seven species are subject to similar threats of comparable magnitude, primarily the loss and degradation of habitat due to deforestation and other ongoing development practices affecting southeastern Brazil, as well as concomitant threats due to severely restricted distributions and small population sizes (such as potential loss of genetic viability). Combining species that face similar threats within the same general geographic area into one proposed rule allows us to maximize our limited staff resources, thus increasing our ability to complete the listing process for warrantedbutprecluded species.
Previous Federal Actions
On November 28, 1980, we received a petition (the 1980 petition) from Dr. Warren B. King, Chairman, United States Section of the International Council for Bird Preservation (ICBP), to add 60 foreign bird species to the List of Endangered and Threatened Wildlife (50 CFR 17.11(h)), including 5 of the 7 Brazilian bird species (blackhooded antwren, cherrythroated tanager, fringebacked fireeye, Margaretta's hermit, and southeastern rufousvented groundcuckoo) that are the subject of this proposed rule. Two of the foreign species identified in the petition were already listed under the Act; therefore, in response to the 1980 petition, we published a substantial 90day finding on May 12, 1981 (46 FR 26464), for 58 foreign species and initiated a status review. On January 20, 1984 (49 FR 2485), we published a 12month finding within an annual review on pending petitions and description of progress on all pending petition findings. In that notice, we found that all 58 foreign bird species from the 1980 petition were warranted but precluded by higher priority listing actions. On May 10, 1985, we published the first annual notice (50 FR 19761) in which we continued to find that listing all 58 foreign bird species from the 1980 petition was warranted but precluded. We published additional annual notices on the 58 species included in the 1980 petition on January 9, 1986 (51 FR 996), July 7, 1988 (53 FR 25511), December 29, 1988 (53 FR 52746), April 25, 1990 (55 FR 17475), November 21, 1991 (56 FR 58664), and May 21, 2004 (69 FR 29354). These notices indicated that the blackhooded antwren, cherrythroated tanager, fringebacked fireeye, Margaretta's hermit, and southeastern rufousvented groundcuckoo, along with the remaining species in the 1980 petition, continued to be warranted but precluded.
On May 6, 1991, we received a second petition (the 1991 petition) from ICBP to add an additional 53 foreign bird species to the List of Endangered and Threatened Wildlife, including the 2 remaining Brazilian bird species (Brazilian merganser and Kaempfer's todytyrant) that are the subject of this proposed rule. In response to the 1991 petition, we published a substantial 90day finding on December 16, 1991 (56 FR 65207), for all 53 species and initiated a status review. On March 28, 1994 (59 FR 14496), we published a 12month finding on the 1991 petition, along with a proposed rule to list 30 African birds under the Act (15 each from the 1980 petition and 1991 petition). In that document, we announced our finding that listing the remaining 38 species from the 1991 petition, including the Brazilian merganser and Kaempfer's todytyrant, was warranted but precluded by higher priority listing actions. We made a subsequent warrantedbutprecluded finding for all outstanding foreign species from the 1980 and 1991 petitions, including the seven Brazilian bird species that are the subject of this proposed rule, as published in our annual notice of review (ANOR) on May 21, 2004 (69 FR 29354).
Per the Service's listing priority guidelines (September 21, 1983; 48 FR 43098), our 2007 ANOR identified the listing priority numbers (LPNs) (ranging from 1 to 12) for all outstanding foreign species. The LPNs for the seven Brazilian bird species that are the subject of this proposed rule are as follows: The blackhooded antwren, Brazilian merganser, cherrythroated tanager, fringebacked fireeye, and Kaempfer's todytyrant (LPN 2); and the Margaretta's hermit and southeastern rufousvented groundcuckoo (LPN 3). Listing priorities of 2 and 3 indicate that the subject species and subspecies, respectively, face imminent threats of high magnitude. With the exception of listing priority ranking of 1, which addresses monotypic genera that face imminent threats of high magnitude, categories 2 and 3 represent the Service's highest priorities.
On July 29, 2008 (73 FR 44062), we published in the Federal Register a notice announcing our annual petition findings for foreign species. In that notice, we announced listing to be warranted for 30 foreign bird species, including the seven Brazilian bird species which are the subject of this proposed rule, and stated that we would ``promptly publish proposals to list these 30 taxa.''
On September 8, 2008, the Service received a 60day notice of intent to sue from the Center for Biological Diversity (CBD) over violations of section 4 of the Act for the Service's failure to promptly publish listing proposals for the 30 ``warranted'' species identified in our 2008 ANOR. Under a settlement agreement approved by the U.S. District Court for the Northern District of California on June 15, 2009, (CDB v. Salazar, 09cv02578CRB), the Service must submit to the Federal Register proposed listing rules for the blackhooded antwren, Brazilian merganser, cherrythroated tanager, fringebacked fireeye, Kaempfer's todytyrant, Margaretta's hermit, and southeastern rufousvented groundcuckoo by July 31, 2009.
Species Information and Factors Affecting the Species
Section 4 of the Act (16 U.S.C. 1533), and its implementing regulations at 50 CFR part 424, set forth the procedures for adding species to the Federal Lists of Endangered and Threatened Wildlife and Plants. A species may be determined to be an endangered or threatened species due to one or more of the five factors described in section 4(a)(1) of the Act. The five factors are: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) overutilization for commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) the inadequacy of existing regulatory mechanisms; and (E) other natural or manmade factors affecting its continued existence. Listing actions may be warranted based on any of the above threat factors, singly or in combination.
If we consider that wildlife habitat is not only defined by
substrates (vegetation, soil, water), but also atmospheric conditions,
then changes in air temperature and moisture can effectively change a
species' habitat. Climate change is characterized by variations in the
earth's temperature and precipitation causing changes in atmospheric,
oceanic, and terrestrial conditions (Parmesan and Mathews 2005, p.
334). Global climate change and other periodic climatic patterns (e.g.,
El Ni[ntilde]o and La Ni[ntilde]a) can cause or exacerbate such
negative impacts on a broad range of terrestrial ecosystems and
neotropical bird populations (Crick 2004, p. 1; England 2000, p. 86; [[Page 40652]]
Holmgren et al. 2001, p. 89; Plumart 2007, pp. 12). For example, trees
cool their area of influence through high rates of evapotranspiration,
or water loss to the atmosphere from their leaves (Parmesan and Mathews
2005, p. 337). Areas where trees have been replaced with pastures have
lower evapotranspiration rates, thus causing local areas to be warmer
(Parmesan and Mathews 2005, p. 337). According to the Intergovernmental
Panel on Climate Change (IPCC), climate change can contribute to
modifications of Amazonian rainforest habitats that are affected by
deforestation (IPCC 1997, p. 11). Parmesan and Mathews (2005, p. 373)
suggest that climate change is more likely to cause range reductions
rather than range shifts. This may be due to the lack of areas where a
species could shift to or the spaces between habitat patches are too
large for individuals to reach. This suggests that climate change could be an agent of habitat loss or modification.
Despite the fact that global climate changes are occurring and affecting habitat, the climate change models that are currently available are not yet able to make meaningful predictions of climate change for specific, local areas (Parmesan and Matthews 2005, p. 354), such as the Atlantic Forest and Cerrado (savanna) bioregions. In addition, we do not have models to predict how the climate in the range of these Brazilian bird species will change, and we do not know how any change that may occur, would affect these species. We also do not have information on past and future weather patterns within the specific range of these species. Therefore, based on the current lack of information and data, we did not evaluate climate change as a threat to these species. We are, however, seeking additional information on this subject (see Public Comments) that can be used in preparing the final rule.
Below is a speciesbyspecies analysis of the five factors. The
species are considered in alphabetical order, beginning with the black
hooded antwren, followed by the Brazilian merganser, cherrythroated
tanager, fringebacked fireeye, Kaempfer's todytyrant, Margaretta's hermit, and the southeastern rufousvented groundcuckoo.
I. Blackhooded Antwren (Formicivora erythronotos)
Species Description
The blackhooded antwren measures 10.5 to 11.5 centimeters (cm) (4 to 4.5 inches (in)) (BirdLife International (BLI) 2007d, p. 1; Sisk 1993, p. 414). Males are black with a reddishbrown back. They have a black narrow bill and a long tail. There are three thin white stripes on the wings. Females have similar coloring, except they have brown olive feathers where black feathers appear on males (BLI 2007d, p. 1). Taxonomy
The blackhooded antwren is a small member of the diverse ``antbird'' family (Thamnophilidae). The species was previously recognized under the genus Myrmotherula (BLI 2007d, p. 1; Collar et al. 1992, p. 667; Sick 1993, p. 414).
Habitat and Life History
The Atlantic Forest biome encompasses a region of tropical and subtropical moist forests, tropical dry forests, and mangrove forests, that extend along the Atlantic coast of Brazil from Rio Grande do Norte in the north to Rio Grande do Sul in the south, and inland as far as Paraguay and Misiones Province of northeastern Argentina (Conservation International 2007a, p. 1; H[ouml]fling 2007, p. 1; Morellato and Haddad 2000, pp. 786787). The blackhooded antwren inhabits lush understories of remnant oldgrowth and early successional secondary growth coastal forests, and it may also occur in dense understories of modified ``restinga,'' (``restinga'' is a Brazilian term that describes a patchwork of vegetation types consisting of beach vegetation, open shrubby vegetation, and dry and swamp forests distributed over coastal plains from northeastern to southeastern Brazil (McGinley 2007, pp. 1 2)), swampy woodlands, abandoned banana plantations, and eucalyptus stands (BLI 2007d, p. 1; Tobias and Williams 1996, p. 64).
Although the specific habitat requirements of the blackhooded antwren are still unclear, the species is not considered a tropical forest specialist. The blackhooded antwren typically forages in pairs or small family groups and consumes various insects, spiders, and small frogs (Collar et al. 1992, p. 667; del Hoyo 2003, p. 616; Sick 1993, p. 405; Tobias and Williams 1996, p. 65). Blackhooded antwrens usually forage in dense vegetation within approximately 3 meters (m) (10 feet (ft)) of the ground, but they are also known to feed higher up (ca. 7 m (23 ft)).
Females typically lay two eggs in fragile nests resembling small cups made of plant material (e.g., rootlets, stems, moss) that are attached to horizontal branches within roughly 1 m (3.3 ft) of the ground (Collar et al. 1992, p. 667; Sick 1993, p. 405). Both sexes help to build the nests, brood clutches, and attend their young. Range and Distribution
The blackhooded antwren is endemic to the Atlantic Forest biome in the southeast of the state of Rio de Janeiro (BLI 2007d, p. 1; Collar et al. 1992, p. 667). Currently, the only confirmed population is believed to be restricted to remnant patches of forest habitat along roughly 30 kilometers (km) (19 miles (mi)) of coast in southern Rio de Janeiro, near the border with S[atilde]o Paulo (Browne 2005, p. 95; Tobias and Williams 1996, p. 64). However, there have also been recent unconfirmed reports that the species may occur at the state Ecological Reserve of Jacarepi[aacute], located roughly 75 km (47 mi) northeast of the city of Rio de Janeiro (ADEJA 2007, p. 3; WorldTwitch 2007, p. 12). Population Estimates
The blackhooded antwren was known from 20 specimens that were purportedly collected in the 1800s in montane forest habitats of central Rio de Janeiro, Brazil. The species had not been reported since that collection until it was rediscovered in 1987 in the Atlantic forest in south Rio de Janeiro (BLI 2007d, p. 1).
The extant population is estimated to be between 1,000 and 2,499 birds, and is fragmented among seven occupied sites, including Bracu[iacute], Frade, S[atilde]o Gon[ccedil]alo, Taquari and Barra Grande, Arir[oacute], and Vale do Mambucaba. Vale do Mambucaba has the highest known density of pairs (156 pairs per square kilometer (km\2\)), followed by Mambucaba (densities of 89 pairs/km\2\). There are no known estimates for the other locations, but it is believed that the numbers are few (BLI 2007d, p. 1). At least one of the fragmented populations is believed to be reproductively isolated. The population, as a whole, is also believed to be declining rapidly due to continued loss of habitat (BLI 2007d, pp. 13).
Conservation Status
The IUCN considers the blackhooded antwren to be ``Endangered''
because ``it has a very small and severely fragmented range that is
likely to be declining rapidly in response to habitat loss'' (BLI
2007d, p. 3). The species is also protected by Brazilian law and occurs
in the buffer area of Serra da Boca[iacute]na National Park (BLI 2007d, p. 2).
[[Page 40653]]
Summary of Factors Affecting the Blackhooded Antwren
A. The Present or Threatened Destruction, Modification, or Curtailment of the Species' Habitat or Range
Based on a number of recent estimates, 92 to 95 percent of the area historically covered by tropical forests within the Atlantic Forest biome has been converted or severely degraded as a result of various human activities (Butler 2007, p. 2; Conservation International 2007a, p. 1; H[ouml]fling 2007, p. 1; Morellato and Haddad 2000, p. 786; Myers et al. 2000, pp. 853854; The Nature Conservancy 2007, p. 1; Saatchi et al. 2001, p. 868; World Wildlife Fund 2007, pp. 241). In addition to the overall loss and degradation of native habitats within this biome, the remaining tracts of habitat are severely fragmented. The current rate of habitat decline is unknown.
The region has the two largest cities in Brazil, S[atilde]o Paulo and Rio de Janeiro, and is home to approximately 70 percent of Brazil's 169 million people (CEPF 2002; IBGE 2007). The major human activities that have resulted in the loss, degradation, and fragmentation of native habitats within the Atlantic Forest biome include extensive establishment of agricultural fields (e.g., soy beans, sugarcane, corn), plantations (e.g., eucalyptus, pine, coffee, cocoa, rubber, bananas), livestock pastures, centers of human habitation, and industrial developments (e.g., charcoal production, steel plants, hydropower reservoirs). Forestry practices (e.g., commercial logging, subsistence activities, fuelwood collection) and changes in fire frequencies (BLI 2003a, p. 4; J[uacute]nior et al. 1995, p. 147; The Nature Conservancy 2007, p. 2; Nunes and Kraas 2000, p. 44; Peixoto and Silva 2007, p. 5; Saatchi et al. 2001, pp. 868869; Scott and Brooke 1985, p. 118; World Wildlife Fund 2007, pp. 351) also contribute to the degradation of native habitat.
The blackhooded antwren is not strictly tied to primary forest habitats and can make use of secondarygrowth forests or other disturbed areas, such as modified ``restinga,'' eucalyptus stands, abandoned banana plantations, and recently burned sites (BLI 2007d, p. 1; Tobias and Williams 1996, p. 64). However, this does not necessarily lessen the threat to the species from the effects of deforestation and habitat degradation. Atlantic Forest birds, such as the blackhooded antwren, which are tolerant of secondarygrowth forests or other disturbed sites, are also rare or have severely restricted ranges (i.e., less than 21,000 km\2\ (8,100 square miles (mi\2\))). Thus habitat degradation can adversely impact such species, just as equally as it impacts primary forestobligate species (Harris and Pimm 2004, pp. 16121613). While the blackhooded antwren is relatively abundant locally, the entire range of the species encompasses only about 130 km\2\ (50 mi\2\), with only 45 percent of this area considered occupied (BLI 2007d, pp. 34).
The susceptibility to habitat destruction of limitedrange species that are tolerant of secondarygrowth forests or other disturbed sites can occur for a variety of reasons, such as when a species' remaining population is already too small or its distribution too fragmented such that it may not be demographically or genetically viable (Harris and Pimm 2004, pp. 16121613). In addition, while the blackhooded antwren may be tolerant of secondarygrowth forests or other disturbed sites, these areas may not represent optimal conditions for the species, which would include dense understories and abundant prey species. For example, management of plantations often involves intensive control of the site's understory vegetation and longterm use of pesticides, which eventually results in severely diminished understory cover and potential prey species (Rolim and Chiarello 2004, pp. 26872691; Saatchi et al. 2001, pp. 868869; Scott and Brooke 1985, p. 118). Such management activities make these sites unsuitable for the blackhooded antwren (BLI 2007d, p. 2).
Impacts associated with the destruction of native habitat by human activities within the Atlantic Forest biome include extensive fragmentation of the remaining tracts of forested habitat potentially used by the blackhooded antwren (see Factor E). As a secondary impact, habitat destruction of these remaining tracts increases the potential introduction of disease vectors or exotic predators within the species' historic range (see Factor C). Furthermore, even when potentially occupied sites may be formally protected, such as the state Ecological Reserve of Jacarepi[aacute] (see Factor D), the remaining fragments of forested habitat will likely undergo further degradation due to their altered dynamics and isolation (ADEJA 2007, pp. 12; Tabanez and Viana 2000, pp. 929932). Altered dynamics and isolation are characterized by a decrease in gene flow and inbreeding, which decrease the fitness of forest species (Tabanez and Viana 2000, pp. 929932). In addition, fragmented Atlantic forests of Brazil are observed to be overtaken by lianas (longstemmed woody vines), which cause tree falls and gaps in the forest structure. These gaps in the forest encourage gap opportunistic vegetation to grow. Hence, a decrease in gene flow, and increases in inbreeding, liana density, and presence of gap opportunistic species change the character and dynamics of the Atlantic Forest biome and isolate fragmented habitat patches (Tabanez and Viana 2000, pp. 930931). These changes may result in the loss of important species that comprise the blackhooded antwren habitat. As a result of these secondary impacts, there is often a time lag between the initial conversion or degradation of suitable habitats and the extinction of endemic bird populations (Brooks et al. 1999a, p. 1; Brooks et al. 1999b, p. 1140). Therefore, even without further habitat loss or degradation, the blackhooded antwren remains at risk from past impacts to its suitable habitats.
The blackhooded antwren occurs in one of the most densely populated regions of Brazil, and most of the tropical forest habitats believed to have been used historically by the species have been converted or are severely degraded due to the wide range of human activities identified above (BLI 2003a, p. 4; BLI 2007d, p. 2; Collar et al. 1992, p. 667; Conservation International 2007a, p. 1; del Hoyo 2003, p. 616; H[ouml]fling 2007, p. 1; The Nature Conservancy 2007, p. 1; World Wildlife Fund 2007, pp. 351). In addition, the remaining tracts of suitable habitat in Rio de Janeiro and S[atilde]o Paulo are threatened by ongoing development of coastal areas, primarily for tourism enterprises (e.g., large hotel complexes, beachside housing) and associated infrastructure support, as well as widespread clearing for expansion of livestock pastures and plantations, primarily for Euterpe palms (BLI 2003a, p. 4; BLI 2007d, p. 2; Collar et al. 1992, p. 667; del Hoyo 2003, p. 616; World Wildlife Fund 2007, pp. 7 and 3637). These impacts have recently reduced suitable habitats at various key sites known to be occupied by the blackhooded antwren such as Vale do Mambucaba and Arir[oacute], and the remaining occupied habitats at these sites are subject to ongoing human disturbances, such as offroad vehicle use, burning, and recreational activities (BLI 2007d, p. 2; Collar et al. 1994, p. 134; del Hoyo 2003, p. 616).
Summary of Factor A
A significant portion of Atlantic Forest habitats have been, and
continue to be, lost and degraded by various ongoing human activities, including
[[Page 40654]]
logging, establishment and expansion of plantations and livestock
pastures, urban and industrial developments (including many new
hydroelectric dams), slashandburn clearing, intentional and
accidental ignition of fires, and establishment of invasive species
(CEPF 2001, pp. 915). Even with the recent passage of a national
forest policy and in light of many other legal protections in Brazil
(see Factor D), the rate of habitat loss throughout the Atlantic Forest
biome has increased since the mid1990s (CEPF 2001, p. 10; Hodge et al.
1997, p. 1; Rocha et al. 2005, p. 270), and native habitats at many of
the remaining sites may be lost over the next several years (Rocha et
al. 2005, p. 263). Furthermore, because the blackhooded antwren's
extant population is already small, highly fragmented, and believed to
be declining (BLI 2007d, pp. 13), any further loss or degradation of
its remaining suitable habitat represents a significant threat to the
species (see Factor E). Therefore, we find that destruction and
modification of habitat are threats to the continued existence of the blackhooded antwren throughout its range.
B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes
The extant population of the blackhooded antwren is considered to be small, fragmented, and declining. The species was deliberately not collected when it was rediscovered in 1987 (Collar et al. 1992, p. 667). This is because the removal or dispersal of just a few individuals from any of the blackhooded antwren's subpopulations or even a slight decline in their fitness due to intentional or inadvertent hunting, specimen collection, or other human disturbances (e.g., scientific research, birding) could represent significant risks to the species' overall viability (see Factor E). However, while these potential influences remain a concern for future management of the species, we are not aware of any other information currently available that indicates the use of this species for any commercial, recreational, scientific, or educational purpose. As a result, we are not considering overutilization to be a contributing factor to the continued existence of the blackhooded antwren.
C. Disease or Predation
Large, stable populations of wildlife species have adapted to natural levels of disease and predation within their historic ranges. However, the extant population of the blackhooded antwren is considered to be small, fragmented, and declining. In addition, extensive human activity in previously undisturbed or isolated areas can lead to the introduction and spread of exotic diseases, some of which (e.g., West Nile virus) can negatively impact endemic bird populations (Naugle et al. 2004, p. 704; Neotropical News 2003, p. 1). Extensive human activity in previously undisturbed or isolated areas can also result in altered predator populations and the introduction of various exotic predator species, some of which (e.g., feral cats (Felis catus) and rats (Ratus sp.)) can be especially harmful to populations of endemic bird species (American Bird Conservancy 2007, p. 1; Courchamp et al. 1999, p. 219; Duncan and Blackburn 2007, pp. 149150; Salo et al. 2007, pp. 12411242; Small 2005, p. 257). Any additive mortality to the blackhooded antwren's subpopulations or a decrease in their fitness due to an increase in the incidence of disease or predation could represent significant threats to the species' overall viability (see Factor E).
Although disease and predation may be a concern for future management of the blackhooded antwren, we are not aware of any speciesspecific information currently available that indicates that disease or predation poses a threat to the species. As a result, we are not considering disease or predation to be a contributing factor to the continued existence of the blackhooded antwren.
D. The Inadequacy of Existing Regulatory Mechanisms
The blackhooded antwren is formally recognized as ``endangered'' in Brazil (Order No. 1.522) and is directly protected by various laws promulgated by the Brazilian government (BLI 2007d, p. 2; Collar et al. 1992, p. 667; ECOLEX 2007, pp. 12). For example, there are measures that prohibit, or regulate through Federal agency oversight, the following activities with regard to endangered species: export and international trade (e.g., Decree No. 76.623, Order No. 419P), hunting (e.g., Act No. 5.197), collection and research (Order No. 332), captive propagation (Order No. 5), and general harm (e.g., Decree No. 3.179). In addition, there are a wide range of regulatory mechanisms in Brazil that indirectly protect the blackhooded antwren through measures that protect its remaining suitable habitat (ECOLEX 2007, pp. 25). For example, there are measures that: (1) Prohibit exploitation of the remaining primary forests within the Atlantic Forest biome (e.g., Decree No. 750, Resolution No. 10); (2) govern various practices associated with the management of primary and secondary forests, such as logging, charcoal production, reforestation, recreation, and water resources (e.g., Resolution No. 9, Act No. 4.771, Decree No. 1.282, Decree No. 3.420, Order No. 74N, Act No. 7.803); (3) establish provisions for controlling forest fires (e.g., Decree No. 97.635, Order No. 231P, Order No. 292P, Decree No. 2.661); and (4) regulate industrial developments, such as hydroelectric plants and biodiesel production (e.g., Normative Instruction No. 65, Law No. 11.116). Finally, there are various measures (e.g., Law No. 11.516, Act No. 7.735, Decree No. 78, Order No. 1, Act No. 6.938) that direct Federal and state agencies to promote the protection of lands and natural resources under their jurisdictions (ECOLEX 2007, pp. 56).
There are also various regulatory mechanisms in Brazil that govern the formal establishment and management of protected areas to promote conservation of the country's natural resources (ECOLEX 2007, pp. 67). These mechanisms generally aim to protect endangered wildlife and plant species, genetic resources, overall biodiversity, and native ecosystems on Federal, state, and privately owned lands (e.g., Law No. 9.985, Law No. 11.132, Resolution No. 4, Decree No. 1.922). Brazil's formally established protection areas are categorized based on their overall management objectives (e.g., National Parks versus Biological Reserves); and based on those categories, they allow varying uses and provide varying levels of protection for specific resources (Costa 2007, pp. 519).
The blackhooded antwren occurs in the buffer zone around Serra da
Bocaina National Park and, possibly, within Tamoios Environmental
Protection Area and the Ecological Reserve of Jacarepi[aacute] (BLI
2007d, p. 2; del Hoyo 2003, p. 616; WorldTwitch 2007, p. 12). It has
been recommended that some of these sites should be expanded and other
sites designated to ensure the species' currently occupied range is
encompassed within protected areas. However, for various reasons (e.g.,
lack of funding, personnel, or local management commitment), some of
Brazil's protected areas exist without the current capacity to achieve
their stated natural resource objectives (ADEJA 2007, pp. 12; Bruner
et al. 2001, p. 125; Costa 2007, p. 7; IUCN 1999, pp. 2324;
Neotropical News 1996, pp. 910; Neotropical News 1999, p. 9).
Therefore, even with the expansion or further designation of protected
areas, it is likely that not all of the identified resource concerns for
[[Page 40655]]
the blackhooded antwren (e.g., residential and agricultural
encroachment, resource extraction, unregulated tourism, grazing) would be sufficiently addressed at these sites.
In the past, the Brazilian government, through various regulations, policies, incentives, and subsidies, has actively encouraged settlement of previously undeveloped lands in southeastern Brazil, which helped facilitate the largescale habitat conversions that have occurred throughout the Atlantic Forest biome (Brannstrom 2000, p. 326; Butler 2007, p. 3; Conservation International 2007c, p. 1; Pivello 2007, p. 2; Ratter et al. 1997, pp. 227228; Saatchi et al. 2001, p. 874). More recently, the Brazilian government has given greater recognition to the environmental consequences of such rapid expansion, and has taken steps to better manage some of the natural resources potentially impacted (Butler 2007, p. 7; Costa 2007, p. 7; Neotropical News 1997a, p. 10; Neotropical News 1997b, p. 11; Neotropical News 1998b, p. 9; Neotropical News 2003, p. 13; Nunes and Kraas 2000, p. 45). Despite these efforts, pressures to develop coastal areas containing black hooded antwren habitat for tourism (e.g., large hotel complexes, beachside housing) and plantation agriculture continue to be a threat to the species (ADEJA 2007, pp. 12; BLI 2007d, p. 2; Tobias and Williams 1996, p. 65).
Summary of Factor D
Brazil's wide variety of laws requiring resource protection that
would ultimately benefit the blackhooded antwren are tested by the
intense development pressure that exists in coastal areas south of Rio
de Janeiro. Despite the existence of these regulatory mechanisms,
habitat loss throughout the Atlantic Forest biome has increased for
more than a decade. The existing regulatory mechanisms have proven
difficult to enforce (BLI 2003a, p. 4; Conservation International
2007c, p. 1; Costa 2007, p. 7; The Nature Conservancy 2007, p. 2;
Neotropical News 1997b, p. 11; Peixoto and Silva 2007, p. 5; Scott and
Brooke 1985, pp. 118, 130). As a result, threats to the blackhooded
antwren's remaining habitat are ongoing (see Factor A) due to the
challenges that Brazil faces to balance its competing development and
environmental priorities. Therefore, when combined with Factors A and
E, we find that the existing regulatory mechanisms are inadequate to
ameliorate the current threats to the blackhooded antwren throughout its range.
E. Other Natural or Manmade Factors Affecting the Continued Existence of the Species
Under this factor we explore whether three risks, represented by demographic, genetic, and environmental stochastic events, are substantive to threaten the continued existence of the blackhooded antwren. In basic terms, demographic stochasticity is defined by chance changes in the population growth rate for the species (Gilpin and Soul[eacute] 1986, p. 27). Population growth rates are influenced by individual birth and death rates (Gilpin and Soul[eacute] 1986, p. 27), immigration and emigration rates, as well as changes in population sex ratios. Natural variation in survival and reproductive success of individuals and chance disequilibrium of sex ratios may act in concert to contribute to demographic stochasticity (Gilpin and Soul[eacute] 1986, p. 27). Genetic stochasticity is caused by changes in gene frequencies due to genetic drift, and diminished genetic diversity, and/or effects due to inbreeding (i.e., inbreeding depression) (Lande 1995, p. 786). Inbreeding can have individual or populationlevel consequences either by increasing the phenotypic expression (the outward appearance, or observable structure, function, or behavior of a living organism) of recessive, deleterious alleles or by reducing the overall fitness of individuals in the population (Charlesworth and Charlesworth 1987, p. 231; Shaffer 1981, p. 131). Environmental stochasticity is defined as the susceptibility of small, isolated populations of wildlife species to natural levels of environmental variability and related ``catastrophic'' events (e.g., severe storms, prolonged drought, extreme cold spells, wildfire) (Dunham et al. 1999, p. 9; Mangel and Tier 1994, p. 612; Young 1994, pp. 410412). Each risk will be analyzed specifically for the blackhooded antwren.
Small, isolated populations of wildlife species are susceptible to demographic and genetic problems (Shaffer 1981, pp. 130134). These threat factors, which may act in concert, include: natural variation in survival and reproductive success of individuals, chance disequilibrium of sex ratios, changes in gene frequencies due to genetic drift, diminished genetic diversity and associated effects due to inbreeding (i.e., inbreeding depression), dispersal of just a few individuals, a few clutch failures, a skewed sex ratio in recruited offspring over just one or a few years, and chance mortality of just a few reproductiveage individuals.
There is very little information available regarding the historic distribution and abundance of the blackhooded antwren. However, the species' historic population was likely larger and more widely distributed than today, and it must have maintained a minimum level of genetic interchange among its local subpopulations in order for them to have persisted (Middleton and Nisbet 1997, p. 107; Vil[agrave] et al. 2002, p. 91; Wang 2004, p. 332). The available information indicates that suitable habitats currently occupied by the blackhooded antwren are highly fragmented and that the species' extant population is small and declining (BLI 2007d, pp. 13). Without efforts to maintain buffer areas and reconnect some of the remaining tracts of suitable habitat near the species' currently occupied sites, it is doubtful that the individual tracts are currently large enough to support viable populations of many birds endemic to the Atlantic Forest, like the blackhooded antwren, and the eventual loss of any small, isolated populations appears to be inevitable (Goerck 1997, p. 117; Harris and Pimm 2004, pp. 16091610; IUCN 1999, pp. 2324; Machado and Da Fonseca 2000, pp. 914, 921922; Saatchi et al. 2001, p. 873; Scott and Brooke 1985, p. 118).
Various past and ongoing human activities and their secondary influences continue to impact all of the remaining suitable habitats that may still harbor the blackhooded antwren (see Factors A and D). We expect that any additional loss or degradation of habitats that are used by the blackhooded antwren will have disproportionately greater impacts on the species due to the population's fragmented state. This is because with each contraction of an existing subpopulation, the likelihood of interchange with other subpopulations within patches decreases, while the likelihood of its complete reproductive isolation increases.
The combined effects of habitat fragmentation (Factor A) and
genetic and demographic stochasticity on a species population are
referred to as patch dynamics. Patch dynamics can have profound effects
on fragmented subpopulations and can potentially reduce a species'
respective effective population by orders of magnitude (Gilpin and
Soul[eacute] 1986, p. 31). For example, an increase in habitat
fragmentation can separate subpopulations to the point where
individuals can no longer disperse and breed among habitat patches,
causing a shift in the demographic characteristics of a population and
a reduction in genetic fitness (Gilpin and Soul[eacute] 1986, [[Page 40656]]
p. 31). Furthermore, as a species' status continues to decline, often
as a result of deterministic forces such as habitat loss or
overutilization, it will become increasingly vulnerable to a broad
array of other forces. If this trend continues, its ultimate extinction due to one or more stochastic events becomes more likely.
We expect that the blackhooded antwren's increased vulnerability to demographic stochasticity and inbreeding will be operative even in the absence of any humaninduced threats or stochastic environmental events, which only act to further exacerbate the species' vulnerability to local extirpations and eventual extinction. Demographic and genetic stochastic forces typically operate synergistically. Initial effects of one threat factor can later exacerbate the effects of other threat factors, as well as itself (Gilpin and Soul[eacute] 1986, pp. 2526). For example, any further fragmentation of the populations will, by definition, result in the further removal or dispersal of individuals, which will exacerbate the other threats. Conversely, lack of a sufficient number of individuals in a local area or a decline in their individual or collective fitness may cause a decline in the population size, despite the presence of suitable habitat patches.
Small, isolated populations of wildlife species, such as the black hooded antwren, are also susceptible to natural levels of environmental variability and related ``catastrophic'' events (e.g., severe storms, prolonged drought, extreme cold spells, wildfire), which we will refer to as environmental stochasticity (Dunham et al. 1999, p. 9; Mangel and Tier 1994, p. 612; Young 1994, pp. 410412). A single stochastic environmental event can severely reduce existing wildlife populations and, if the affected population is already small or severely fragmented, it is likely that demographic stochasticity or inbreeding will become operative, which would place the population in jeopardy (Gilpin and Soul[eacute] 1986, p. 27; Lande 1995, pp. 787789). Summary of Factor E
The small and declining numbers that make up the blackhooded antwren's population makes it susceptible to natural environmental variability or chance events. In addition to its declining numbers, the high level of population fragmentation makes the species susceptible to genetic and demographic stochasticity. Therefore, we find that demographic, genetic, and environmental stochastic events are a threat to the continued existence of the blackhooded antwren throughout its range.
Status Determination for the Blackhooded Antwren
We have carefully assessed the best available scientific and commercial information regarding the past, present, and potential future threats faced by the blackhooded antwren. The species is currently at risk throughout all of its range due to ongoing threats of habitat destruction and modification (Factor A), and demographic, genetic, and environmental stochastic events associated with the species' high level of population fragmentation (Factor E). Furthermore, we have determined that the existing regulatory mechanisms (Factor D) are not adequate to ameliorate the current threats to the species.
Section 3 of the Act defines an ``endangered species'' as ``any
species which is in danger of extinction throughout all or a
significant portion of its range'' and a ``threatened species'' as
``any species which is likely to become an endangered species within
the foreseeable future throughout all or a significant portion of its
range.'' Based on the threats to the blackhooded antwren throughout
its entire range, as described above, we determine that the black
hooded antwren is in danger of extinction throughout all of its range.
Therefore, on the basis of the best available scientific and commercial
information, we are proposing to list the blackhooded antwren as an endangered species throughout all of its range.
II. Brazilian Merganser (Mergus Octosetaceus)
Species Description
The 4956 cm (1922 in) (BLI 2007a, p. 1) Brazilian merganser is described as resembling a cormorant (Sisk 1993, p. 163). The bird has a white wing speculum and red feet. The breast is pale grey with dark markings, and there is dark grey coloring in the upper breast (BLI 2007a, p. 1). The species has a distinctive green crest that extends over the nape of the neck (more developed in the male) (Sisk 1993, p. 163).
Taxonomy
The Brazilian merganser was first described by Vieillot in 1817 (Partridge 1956, p. 473). The species belongs in the family Anatidae (BLI 2007a, p. 1).
Habitat and Life History
The Brazilian merganser is highly adapted to shallow, rapid, clear water streams and rivers, typically bordered by dense, tropical forest (Bruno et al. 2006, p. 26; Collar et al. 1992, pp. 8086; Ducks Unlimited 2007, p. 1; Hughes et al. 2006, p. 23; Partridge 1956, pp. 478480; Sibley and Monroe 1990, p. 41). Where suitable riverine conditions exist, the Brazilian merganser also occurs in the Cerrado biome, which is characterized by open tropical savannah and comparatively sparse ``gallery'' forest at the river margins, indicating that the species is not strictly tied to tropical forest habitats (Bianchi et al. 2005, p. 73; Braz et al. 2003, p. 70).
Brazilian mergansers are strong swimmers and divers. They typically feed in river rapids or in pools adjacent to waterfalls, whereas they rest and perch in more slack water areas or at the river edges (Braz et al. 2003, p. 70; Hughes et al. 2006, p. 21; Partridge 1956, pp. 481 482). Brazilian mergansers feed primarily on a variety of fish species, with sizes up to approximately 19 cm (7.5 in), and occasionally on insects, snails, and other aquatic macroinvertebrates (Hughes et al. 2006, p. 32; Partridge 1956, p. 483).
Brazilian mergansers are believed to be monogamous and sedentary. Breeding pairs appear to maintain their territories along a stretch of river (up to ca. 12 km (7.5 mi)) throughout the year (Braz et al. 2003, p. 70; Ducks Unlimited 2007, p. 1; Hughes et al. 2006, pp. 23, 33; Partridge 1956, p. 477). The breeding season begins in June and young hatch around August (Partridge 1956, p. 487). Females establish their nests relatively high up (25 m (82 ft)) in the cavities of tall trees that overlook the river and incubate their eggs alone, although males are attentive and remain nearby feeding and perching at the river shoreline (Bruno et al. 2006, p. 29; Lamas and Santos 2004, p. 38; Partridge 1956, pp. 484485). Females may also locate their nests lower down (10 m (33 ft)) in the cavities of cliffs or rocky outcrops near preferred riverine habitat in areas where suitable nesting trees are absent (Lamas and Santos 2004, pp. 3839).
Range and Distribution
The Brazilian merganser occurs in a few fragmented locations in
southcentral Brazil, including the uppertributaries of rivers within
the Atlantic Forest biome and to the east in the Cerrado (savanna)
biome (BLI 2007a, p. 1). The species is a diving duck that occurred
historically in riverine habitats throughout southeastern Brazil,
northeastern Argentina, and eastern Paraguay (Hughes et al. 2006, p.
24). Currently, the species is found in extremely low numbers at six
highly disjunct localities, of which five are in southeastern Brazil and one is in northeastern Argentina and, possibly,
[[Page 40657]]
extreme eastern Paraguay (BLI 2007a, pp. 15; Hughes et al. 2006, pp.
2831). The vast majority of the species' extant population and
remaining suitable habitats occur in Brazil, including its largest
subpopulation that is estimated to contain fewer than 50 individuals (BLI 2007a, p. 5).
The Brazilian merganser is thought to have been extirpated from Mato Grosso do Sul, S[atilde]o Paolo, Rio de Janeiro, and Santa Catarina (BLI 2007a, pp. 12). There is only a single recent record of the Brazilian merganser (ca. 2002) in the province of Misiones, Argentina, while the last confirmed sighting of the species in Paraguay is from 1984 (BLI 2007a, p. 2; Hughes et al. 2006, p. 31). For purposes of this proposed rule, our analysis will focus on the most current estimates of the species, which are based in Brazil.
The species likely still occurs in the Brazilian states of Tocantins, Bahia, Goi[aacute]s, Minas Gerais, and Paran[aacute] (Hughes et al. 2006, pp. 5152). Along with other recent sightings of the species in previously undocumented areas of Brazil (Bianchi et al. 2005, p. 72; Pineschi 1999, p. 1), this information indicates that the Brazilian merganser may be more abundant and widespread than previously considered.
Population Estimates
The extant population is estimated to be between 50 and 249 individuals and is presumed to be declining, as evidenced by the species' recent history of extirpation from major portions of its historic range (BLI 2007a, p. 1).
Conservation Status
IUCN considers the Brazilian merganser to be ``Critically
Endangered'' because ``although recent records from Brazil, and
particularly a recent northerly range extension, indicate that this
species' status is better than previously thought, the remaining
population is still extremely small and severely fragmented, and the
perturbation and pollution of rivers continues to cause declines'' (BLI
2007a, p. 1). In addition, the species occurs in three parks in Brazil
and in the Urugua[iacute] Provincial Park in Argentina (BLI 2007a, p. 1).
Summary of Factors Affecting the Brazilian Merganser
A. The Present or Threatened Destruction, Modification, or Curtailment of the Species' Habitat or Range
Based on a number of recent estimates, 92 to 95 percent of the area historically covered by tropical forests within the Atlantic Forest biome has been converted or severely degraded as a result of various human activities (Conservation International 2007a, p. 1; H[ouml]fling 2007, p. 1; Morellato and Haddad 2000, p. 786; Myers et al. 2000, pp. 853854; The Nature Conservancy 2007, p. 1; Saatchi et al. 2001, p. 868; World Wildlife Fund 2007, pp. 241). The Cerrado biome has also been heavily impacted by human activities, and current estimates indicate that between 67 and 80 percent of the tropical savannah habitat historically comprising this biome has been converted or severely degraded (Butler 2007, p. 1; Conservation International 2007b, p. 1; Mantovani and Pereira 1998, p. 1455; Myers et al. 2000, p. 854; World Wildlife Fund 2007, p. 50). In addition to the overall loss and degradation of native habitat within these biomes, the remaining tracts of habitat are severely fragmented. The current rate of habitat loss in the Atlantic Forest and Cerrado biomes is unknown.
The region has the two largest cities in Brazil, S[atilde]o Paulo and Rio de Janeiro, and is home to approximately 70 percent of Brazil's 169 million people (CEPF 2002; IBGE 2007). The major human activities that have resulted in the loss, degradation, and fragmentation of native habitats within these biomes include extensive establishment of agricultural fields (e.g., soy beans, sugarcane, and corn), plantations (e.g., eucalyptus, pine, coffee, cocoa, rubber, and bananas), livestock pastures, centers of human habitation, and industrial developments (e.g., diamond mining, hydropower reservoirs, and charcoal production). Forestry practices (e.g., commercial logging), subsistence activities (e.g., collection of fuelwood), and changes in fire frequencies also contribute to the degradation of native habitat (BLI 2003a, p. 4; BLI 2003b, pp. 12; Butler 2007, p. 1; Hughes et al. 2006, pp. 3748; J[uacute]nior et al. 1995, p. 147; Nunes and Kraas 2000, p. 44; Pivello 2007, pp. 12; Ratter et al. 1997, pp. 227228; Saatchi et al. 2001, pp. 868869; World Food Prize 2007, pp. 15; World Wildlife Fund 2007, pp. 351).
The Brazilian merganser is extremely susceptible to habitat loss and degradation, habitat fragmentation, and hydrological changes from human activity (Collar et al. 1992, pp. 8384; Hughes et al. 2006, pp. 3641; Silveira 1998, p. 58). The loss of appropriate aquatic and terrestrial habitats throughout the historic range of the Brazilian merganser due to the above human activities is believed to have drastically reduced the species' abundance and extent of occupied range, and these activities currently represent a significant risk to the species' continued existence because populations are being limited to highly fragmented patches of habitat (Benstead 1994, p. 8; Benstead et al. 1994, p. 36; BLI 2007a, pp. 16; Collar and Andrew 1988, p. 21; Collar et al. 1992, pp. 8384; Collar et al. 1994, p. 51; Hughes et al. 2006, pp. 3748; Silveira 1998, pp. 5758).
The species is highly adapted to shallow, rapidflowing riverine conditions and, therefore, can not occupy the lacustrine conditions of reservoirs that result from dam building activities within their occupied range (Hughes et al. 2006, pp. 23, 41). The loss of the species' terrestrial habitat has occurred due to the removal of forest cover and suitable nesting trees adjacent to occupied river corridors.
A variety of secondary impacts that degrade suitable habitats have also resulted from the above activities and represent significant risks to the Brazilian merganser. These secondary impacts include increased runoff and severe siltation from agricultural fields, livestock pastures, deforestation, diamond mining, and population centers; changes in hydrologic conditions and local water tables as a result of dam operations (e.g., flood control, power generation) and excessive pumping for irrigation or domestic and industrial water use; and increases in water pollutants due to agricultural, industrial, and domestic waste products (Benstead 1994, p. 8; Bianchi et al. 2005, p. 73; BLI 2007a, pp. 16; Braz et al. 2003, p. 70; Collar et al. 1994, p. 51; del Hoyo et al. 1992, p. 625; Ducks Unlimited 2007, p. 1; Hughes et al. 2006, pp. 4048; Lamas and Santos 2004, p. 40; Pineschi 1999, p. 1). These secondary impacts negatively affect the Brazilian merganser by reducing water clarity, altering water depths and flow patterns, removing or limiting populations of preferred prey species; introducing toxic compounds; and creating barriers to movements and producing hazardous conditions along river corridors that limit interchange between the species' remaining subpopulations (see Factor E). These secondary impacts also increase the risk of introducing disease vectors and expanding populations of potential predator and competitor species into areas occupied by the Brazilian merganser (see Factor C). Summary of Factor A
The above mentioned human activities and their secondary impacts
have significantly reduced the amount of suitable habitat for the Brazilian merganser (Benstead 1994, p. 8;
[[Page 40658]]
Benstead et al. 1994, p. 36; BLI 2007a, pp. 16; Collar and Andrew
1988, p. 21; Collar et al. 1992, pp. 8384; Collar et al. 1994, p. 51;
Hughes et al. 2006, pp. 3748; Silveira 1998, pp. 5758), and the
remaining areas of occupied habitat are highly fragmented (see Factor
E). In addition, these activities are ongoing and continue to adversely
impact all of the remaining suitable habitat within the Atlantic Forest
and Cerrado biomes that may still harbor the Brazilian merganser (BLI
2003a, p. 4; BLI 2003b, pp. 12; BLI 2007a, pp. 17; Brannstrom 2000,
p. 326; Ducks Unlimited 2007, p. 1; Harris and Pimm 2004, p. 1610;
Hughes et al. 2006, pp. 3748; Morellato and Haddad 2000, p. 786;
Saatchi et al. 2001, pp. 868873; Tabanez and Viana 2000, pp. 929932).
Even with the recent passage of national forest policy and in light of
many other legal protections in Brazil (see Factor D), the rate of
habitat loss throughout southeastern Brazil has increased since the
mid1990s (CEPF 2001, p. 10; Hodge et al. 1997, p. 1; Rocha et al.
2005, p. 270). Furthermore, because the Brazilian merganser's extant
population is already extremely small, highly fragmented, and believed
to be declining (BLI 2007a, pp. 14), any further loss or degradation
of its remaining suitable habitat will severely impact the species (see
Factor E). Therefore, we find that destruction and modification of
habitat are threats to the continued existence of the Brazilian merganser throughout its range.
B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes
Historically, there was likely little rangewide hunting pressure on the Brazilian merganser, presumably due to the species' secretive nature, naturally low densities in relatively inaccessible areas, and poor palatability (Partridge 1956, p. 478). However, low levels of subsistence hunting of some local populations still occurs, most notably in Argentina (Benstead 1994, p. 8; del Hoyo et al. 1992, p. 625; Hughes et al. 2006, p. 48).
Since the first formal description of the species in the early 1800s, the Brazilian merganser has also been collected for scientific study and museum exhibition (BLI 2007a, p. 2; Hughes et al. 2006, p. 46). Past hunting and specimen collection may have contributed to the species' decline in some areas (Hughes et al. 2006, p. 46). These activities continue today, although presumably at low levels (Benstead 1994, p. 8; Hughes et al. 2006, p. 48; Lamas and Santos 2004, p. 39). Summary of Factor B
Species collection for scientific study and museum exhibition, and hunting, are believed to affect the population of the Brazilian merganser. Considering the extremely small size and level of fragmentation of the extant Brazilian merganser population, the removal or dispersal of any individuals from a local area, or even a slight decline in the population's fitness, represent significant risks to the species' overall viability (see Factor E). However, we do not have information on the extent of species collection or hunting to determine whether these activities are a threat to the continued existence of the species. As a result, we are not considering overutilization to be a contributing factor to the continued existence of the Brazilian merganser.
C. Disease or Predation
Extensive human activity in previously undisturbed or isolated areas can lead to the introduction and spread of exotic diseases, some of which (e.g., West Nile virus) can negatively impact endemic bird populations (Neotropical News 2003, p. 1; Naugle et al. 2004, p. 704). In addition, there are a number of suspected predators of the Brazilian merganser (Hughes et al. 2006, p. 44; Lamas and Santos 2004, p. 39; Partridge 1956, p. 486). Partridge (1956, p. 480) hypothesized that the species' distribution may be naturally limited to upper river tributaries above waterfalls due to predation of their young by large predatory fish, such as the dourado (Salminus brasiliensis, syn. maxillosus). Finally, extensive human activity in previously undisturbed or isolated areas can result in altered predator or competitor (e.g., cormorant (Phalacrocorax sp.)) populations and the introduction of various exotic predator species, such as feral dogs (Canis familiaris) and game fish like largemouth bass (Micropterus salmoides) (Hughes et al. 2006, pp. 4445).
The available information indicates that there is a greatly expanded human population within the Brazilian merganser's historic range and that the species' extant population is extremely small, highly fragmented, and likely declining. Although large, stable populations of wildlife species have adapted to natural levels of disease and predation within their historic ranges, any additive mortality to the Brazilian merganser population or a decrease in its fitness due to an increase in the incidence of disease or predation could adversely impact the species' overall viability (see Factor E). However, while these potential influences remain a concern for future management of the species, we are not aware of any information currently available that specifically indicates the occurrence of disease in the Brazilian merganser, or that documents actual predation levels incurred by any of the species' local subpopulations. As a result, we are not considering disease or predation to be a contributing factor to the continued existence of the Brazilian merganser.
D. The Inadequacy of Existing Regulatory Mechanisms
The Brazilian merganser is legally protected by national
legislation promulgated by the governments in all three countries where
it historically occurred (Hughes et al. 2006, pp. 5057). In Brazil,
where the vast majority of the species' extant population and remaining
suitable habitats occur (BLI 2007a, pp. 12; Hughes et al. 2006, pp. 2831), the Brazilian merganser is formally recognized as
``endangered'' (Order No. 1.522), and there are regulatory mechanisms
that require direct protection of the species (ECOLEX 2007, pp. 12).
These include measures that prohibit, or regulate through Federal
agency oversight, the following activities with regard to endangered
species: export and international trade (e.g., Decree No. 76.623, Order
No. 419P), hunting (e.g., Act No. 5.197), collection and research
(Order No. 332), captive propagation (Order No. 5), and general harm (e.g., Decree No. 3.179).
There are also a wide range of regulatory mechanisms in Brazil that
indirectly protect the Brazilian merganser through measures that
protect its remaining suitable habitats (ECOLEX 2007, pp. 25). For
example, there are measures that: (1) Prohibit exploitation of the
remaining primary forests within the Atlantic Forest biome and gallery
forests adjacent to river corridors (e.g., Decree No. 750, Resolution
No. 10, Act No. 7.754); (2) govern various practices associated with
the management of primary and secondary forests, such as logging,
charcoal production, reforestation, recreation, and water resources
(e.g., Resolution No. 9, Act No. 4.771, Decree No. 1.282, Decree No.
3.420, Order No. 74N, Act No. 7.803); (3) establish provisions for
controlling forest fires (e.g., Decree No. 97.635, Order No. 231P,
Order No. 292P, Decree No. 2.661); and (4) regulate industrial
developments, such as hydroelectric plants and biodiesel production
(e.g., Normative Instruction No. 65, Law No. 11.116). Measures also exist (e.g., Law No. 11.516, Act No. 7.735, Decree No.
[[Page 40659]]
78, Order No. 1, Act No. 6.938) that direct Federal and State agencies
to promote the protection of lands and natural resources under their jurisdictions (ECOLEX 2007, pp. 56).
Regulatory mechanisms in Brazil govern the formal establishment and management of protected areas to promote conservation of the country's natural resources (ECOLEX 2007, pp. 67). These mechanisms generally aim to protect endangered wildlife and plant species, genetic resources, overall biodiversity, and native ec
FOR FURTHER INFORMATION CONTACT
Douglas Krofta, Chief, Branch of Listing, Endangered Species Program, U.S. Fish and Wildlife Service, 4401 N. Fairfax Drive, Room 420, Arlington, VA 22203; telephone 703 3582105; facsimile 7033581735. If you use a telecommunications device for the deaf (TDD), call the Federal Information Relay Service (FIRS) at 8008778339.