Content uploaded by Luís Fábio Silveira
Author content
All content in this area was uploaded by Luís Fábio Silveira on Mar 10, 2015
Content may be subject to copyright.
A preview of the PDF is not available
Action Plan for the Conservation of the Brazilian Merganser (Mergus octosetaceus)
Figures
Figures - uploaded by Luís Fábio Silveira
Author content
All figure content in this area was uploaded by Luís Fábio Silveira
Content may be subject to copyright.
... The Brazilian Merganser Mergus octosetaceus is an endemic South American waterfowl, inhabiting clear and rapid river courses sided by gallery forest of mountainous regions (Hughes et al., 2006). It is considered rare and threatened of extinction since the 1950s (Partridge, 1956) with no recent records (for the last 15 years) in Argentina, Paraguay, and southern Brazil (Collar et al., 1992;Hughes et al., 2006), places in which the species is likely extinct. ...
... The Brazilian Merganser Mergus octosetaceus is an endemic South American waterfowl, inhabiting clear and rapid river courses sided by gallery forest of mountainous regions (Hughes et al., 2006). It is considered rare and threatened of extinction since the 1950s (Partridge, 1956) with no recent records (for the last 15 years) in Argentina, Paraguay, and southern Brazil (Collar et al., 1992;Hughes et al., 2006), places in which the species is likely extinct. Nowadays, the remaining populations are only found in three regions of Central Brazil: Serra da Canastra (Silveira and Bartmann, 2001;Ribeiro et al., 2018), Chapada dos Veadeiros (Bianchi et al., 2005), and Jalapão (Barbosa et al., 2015). ...
... The Brazilian Merganser is a visual predator and requires clear water for fishing (Partridge, 1956;Hughes et al., 2006), thus river pollution and siltation due to human activity are some of the main threats for the species. The building of dams for energy production poses additional threats to the species Valle, 1990, Hughes et al., 2006) by altering rivers' traits, water quality, and the hydrological cycle (Bunn and Arthington, 2002). ...
The critically endangered Brazilian Merganser Mergus octosetaceus is one of the rarest waterfowls in the world. Only three isolated populations remain in the Brazilian Cerrado, totaling less than 250 individuals. We evaluated the potential influence of small hydroelectric plants (SHPs) and Protected Areas (PAs) on the species’ conservation. We identified suitable areas by using recent presence records and environmental predictors, and overlapped it with the species dispersion zone and the SHP impact zone. Suitable areas for the species are limited to 4% of the geographic space (142,899 km²). Within the dispersion zone, we found 36 planned SHPs, which can impact 4.1% of the suitable area and 17.2% of the suitable area inside PAs. Our results expose the critical situation of the Brazilian Merganser, with few isolated suitable areas, high potential impacts for the three known populations, and a high proportion of suitable areas out of PAs. We highlight the need of considering SHPs impacts on the Brazilian Merganser in environmental impact assessment studies to reduce them. Furthermore, we appointed areas for search of new populations, and emphasize how urgent the implementation of effective conservation actions aiming to protect the remaining suitable habitats for the Brazilian Merganser is.
... The Brazilian Merganser, Mergus octosetaceus (Vieillot, 1817), is a critically endangered (IUCN 2010), fish-eating, riverine duck that inhabits fast-flowing, clear rivers (Antas 1996) and wild population is estimated to be less than 250 individuals (BirdLife_International 2000). Its historical range comprised the tropical and subtropical Atlantic forest and the Cerrado regions of Brazil, Argentina and Paraguay (Hughes et al. 2006 ). At the present time, only a few protected areas and their surroundings in Brazil still hold populations of the species, namely Jalapão State Park (Tocantins state), the National Parks of Chapada dos Veadeiros and Emas (both Goiás state), and Serra da Canastra (Minas Gerais state), with recent discoveries at other sites in Minas Gerais and Bahia states. ...
... At the present time, only a few protected areas and their surroundings in Brazil still hold populations of the species, namely Jalapão State Park (Tocantins state), the National Parks of Chapada dos Veadeiros and Emas (both Goiás state), and Serra da Canastra (Minas Gerais state), with recent discoveries at other sites in Minas Gerais and Bahia states. It is considered locally extinct in Paraguay and Argentina, although there have been rare sightings in recent decades in Argentina (Hughes et al. 2006). At the Serra da Canastra National Park is found the largest remaining population, with approximately 80 individuals documented (Lamas 2006). ...
... The Brazilian Merganser is considered the most threatened of all mergansers, being a rare species that naturally occurs in low densities. It is currently endangered by several threats to its original habitat, perhaps the most important of which is the increased sediment input into rivers, resulting in turbidity and sedimentation, which in turn reduces fish populations and merganser hunting success (Hughes et al. 2006). Considering the current estimates for the total remaining population of the Brazilian Merganser (BirdLife_International 2000), we expect an ongoing erosion of its current genetic diversity. ...
The Brazilian Merganser is a very rare and threatened species that nowadays inhabits only a few protected areas and their
surroundings in the Brazilian territory. In order to estimate the remaining genetic diversity and population structure in
this species, two mitochondrial genes were sequenced in 39 individuals belonging to two populations and in one individual
collected in Argentina in 1950. We found a highly significant divergence between two major remaining populations of Mergus octosetaceus, which suggests a historical population structure in this species. Furthermore, two deeply divergent lineages were found
in a single location, which could due to current or historical secondary contact. Based on the available genetic data, we
point out future directions which would contribute to design strategies for conservation and management of this threatened
species.
Keywords
Mergus octosetaceus
–Conservation–Genetic diversity
... Originally found across south-central Brazil and adjacent Argentina and Paraguay, the species' range is now drastically reduced (Collar et al. 1992), despite its more recent discovery further north than previously known (Braz et al. 2003). Intolerant of impacts to its environment and sensitive to human disturbance, activities such as agricultural expansion, pollution, dams and loss of riverine vegetation can all negatively impact the species (Hughes et al. 2006). Recent sightings evidence its survival in Argentina (Misiones) and perhaps even in Paraguay, but in Brazil it is considered extinct in the states of Mato Grosso do Sul, São Paulo, Rio de Janeiro and Santa Catarina (Collar et al. 1992, Lamas & Lins 2009, Carboneras et al. 2018. ...
Brazilian Merganser Mergus octosetaceus is one of the most endangered bird species in the Americas and one of the rarest ducks in the world. We photographed the species in August 2017, at Serra do Mar State Park, Salesópolis, in eastern São Paulo state. This is the third documented record in São Paulo, but the first for approximately 200 years.
... Originally found across south-central Brazil and adjacent Argentina and Paraguay, the species' range is now drastically reduced (Collar et al. 1992), despite its more recent discovery further north than previously known (Braz et al. 2003). Intolerant of impacts to its environment and sensitive to human disturbance, activities such as agricultural expansion, pollution, dams and loss of riverine vegetation can all negatively impact the species (Hughes et al. 2006). Recent sightings evidence its survival in Argentina (Misiones) and perhaps even in Paraguay, but in Brazil it is considered extinct in the states of Mato Grosso do Sul, São Paulo, Rio de Janeiro and Santa Catarina (Collar et al. 1992, Lamas & Lins 2009, Carboneras et al. 2018. ...
... However, despite all this preventive legislation, large, intense late dry season wildfires are common in Brazilian protected areas Júnior et al., 2013;Mesquita et al., 2011;Silva et al., 2011), emphasizing the gap between fire management policies and realities. For instance, fires burnt large areas on the CP in 2002, including the habitat of mergansers Mergus octosetaceus, a Critically Endangered species at the global level according to IUCN criteria (BirdLife International, 2015), and in Brazil (BRASIL, 2014;Hughes et al., 2006). Only recently, in 2014, strategies were proposed with the aim of joining research with management as part of the development of an Integrated Fire Management Program in the CNP . ...
Fire has shaped plant evolution and biogeochemical cycles for millions of years in savanna ecosystems, but changes in natural fire regimes promoted by human land use threaten contemporary conservation efforts. In protected areas in the Brazilian savannas (Cerrado), the predominant management policy is fire suppression, reflecting a cultural heritage which considers that fire always has a negative impact on biodiversity. Here we compare resultant fire-regimes in Canastra National Park (CNP), southeast Brazil, associated with areas under and without fire suppression management, based on a 16-year Landsat imagery record. In open grasslands of the Canastra plateau (CP), firefighting is undertaken under government-sanctioned regulation, whereas in the Babilonia sector, non-sanctioned fire management is undertaken by small farmers to promote cattle grazing and cropping. Fire regimes in the Canastra sector are characterized by few, very large, late dry season wildfires recurring at intervals of two years. Fire regimes in lowlands of the Babilonia sector are characterized by many small-scale, starting at the beginning of the dry season (EDS). In Babilonia uplands fire regimes are characterized by higher frequencies of large fires. The study illustrates major challenges for managing fire-prone areas in conflict-of-interest regions. We suggest that management planning in CNP needs to effectively address: i) managing conflicts between CNP managers and local communities; and ii) fire management practices in order to achieve more ecologically sustainable fire regimes. The study has broader implications for conservation management in fire-prone savannas in South America generally.
... According to IBAMA (the Brazilian National Agency for the conservation of nature-www.ibama.gov.br), only four species of Brazilian birds have CAMPs, these being the red-billed curassow [Crax blumenbachii: Wajntal et al., 2004], Lear's macaw [Anodorhynchus leari: Barros et al., 2006], the Araripe manakin [Antilophia bokermanni, Gira˜o and Campos, 2006], and the Brazilian merganser [Mergus octosetaceus, Hughes et al., 2006]. The CAMP for albatrosses and petrels does not mention ex situ efforts, only in situ actions [Neves et al., 2006]. ...
Zoos may play an important role in conservation when they maintain and breed large numbers of animals that are threatened with extinction. Bird conservation is in a privileged situation owing to the extensive biological information available about this class. Annual inventories produced by the "Sociedade de Zoológicos do Brasil" in the years 1981, 1990, 2000, and 2005 were analyzed. Variables, such as the number of zoos per geographic region; number of birds held; number of bird species in each IUCN threat category; number of exotic and native bird species; number of potentially breeding bird species; number of bird species in each order; and number of threatened bird species breeding, were analyzed. Brazilian zoos kept more than 350 bird species. The number of bird species and specimens held by the Brazilian Zoos increased from 1981 to 2000, but decreased in 2005. The same pattern was observed for the number of species in each IUCN threat category. Results showed that the potential of the Brazilian zoos in bird conservation needs to be enhanced because they maintain threatened species but do not implement systematic genetic, reproductive, or behavioral management protocols for most species.
The Brazilian Merganser is one of the rarest birds of South America with three known remnant populations in Brazil and only 250 individuals existing in the wild. Thus, evaluating the genetic variability within the remaining population is essential to its conservation. This study assessed genetic diversity of remnant populations by mtDNA (Dloop and cytb) and nDNA (MUSK 13 intron, five microsatellites) markers, giving support to management and conservation efforts. Seventy-one samples were collected during eight years from Chapada dos Veadeiros National Park (PNCV), Serra da Canastra National Park (PNSC), and Alto do Paranaíba region (APR). Cytochrome b, Dloop, and MUSK intron showed only one haplotype, indicating a loss of genetic variability for the Brazilian Merganser. The microsatellites confirmed low genetic variability (1–4 alleles). Despite the low variability observed, it was possible to infer minor differentiation between remnant populations, with PNCV locale being the most differentiated subgroup, due to its being isolated by greater distance from the others. Low genetic diversity observed in Brazilian Merganser, is expected to be found in Critically Endangered species, due to small population size, being result of high inbreeding rates, and gene drift effects. Thus, our genetic data have confirmed the extremely critical status of the Brazilian Merganser, making it necessary to create an immediate recovery program for their populations, and develop a management plan to integrate and preserve all remnant populations to avoid the species extinction.
A population of blue ducks inhabiting the Manganuiateao River, North Island, New Zealand, was studied over 1980-89. The birds were dispersed as pairs throughout the year with each pair occupying and defending territories similar in extent and location between years. Unpaired individuals also occupied territories throughout a breeding season. Pair associations persisted for up to 81 months (seven breeding seasons). Only territorial pairs attempted breeding. Nests were in caves or amongst enveloping riverside vegetation within the territory and the same nest site was sometimes used in successive years. Mean clutch size was 6.0. Only the female incubated (for c35 days); 10% of nest failures were followed by a repeat laying. Both parents contribute parental care throughout the 70-80 day fledging period. Within the 9.3km study area the number of territories occupied increased from four to 10 over 10 yr. Fifty-eight breeding attempts produced 73 fledglings (mean 1.3 per breeding pair per year). Some individuals were more productive than others both in terms of the numbers of fledged per breeding attempt and numbers recruited into the breeding population. Annual survival of territory holders was 0.86, and that of juveniles in their first year 0.44. Recruitment into the breeding component of the population was 0.25 fledglings per breeding individual per year, twice that needed to replace lost adults. Fledglings of both sex were highly philopatric, some establishing their territories immediately adjacent to their natal range. Nineteen of 26 birds which settled in the study area over the 10 yr were progeny of resident pairs and resulted in neighbouring territory holders being closely related to each other. Two sibling pairings persisted through a breeding season and there were two other examples of direct inbreeding (adult-grandchild). -from Author
Phylogenetic relationships of modern seaducks (Mergini) were investigated using a cladistic analysis of 137 morphological characters. The analysis produced a single tree (consistency index = 0.692, excluding autapomorphies) with complete resolution of the relationships among the 25 taxa recognized. Phylogenetic inferences include: (1) the eiders (Polysticta and Somateria) constitute a monophyletic group and are the sister-group of other Mergini; (2) the remaining generic groups of Mergini, sequenced in order of increasingly close relationship, are Histrionicus, Melanitta + Camptorhynchus, Clangula, Bucephala + Mergellus, Lophodytes, and Mergus; (3) Somateria is monophyletic with S. fischeri the sister-group of its congeners; (4) the black scoters (Melanitta nigra-group) are the sister-group of other scoters; (5) the Bufflehead (Bucephala albeola) is the sister-group of the goldeneyes (B. clangula and B. islandica); and (6) relationships among mergansers are as presented by Livezey (1989). Bootstrapping revealed that the placement of the Smew as the sister-group of the goldeneyes is only weakly supported, and ancillary analyses revealed that this placement is only one step shorter than its reduction to a trichotomy with the goldeneyes and mergansers (including Lophodytes). A phylogenetic classification of modern seaducks is presented. The Harlequin Duck (H. histrionicus), Long-tailed Duck (Clangula hyemalis), and Steller's Eider (Polysticta stelleri) are highly autapomorphic. Evolutionary patterns of selected ecomorphological characteristics--including body mass, sexual size dimorphism, clutch size, relative clutch mass, nest site, diet, diving method, formation of crèches, and biogeography--are examined with respect to the phylogenetic hypothesis.