New distribution records of Pteronura brasiliensis (Zimmerman, 1780) (Mammalia, Carnivora) in Roraima, northern Brazilian Amazonia

A survey of the Giant Otter, Pteronura brasiliensis (Zimmerman, 1780), in the state of Roraima, northern Brazilian Amazonia, is presented. We include 52 new records, increasing the total geographic coordinate points for the species in this area by 360%. Additionally, this study reports the first occurrence of the P. brasiliensis in the lavrado region, a unique and endemic ecosystem of South America with high biodiversity, which claims for protection and adequate land use planning.

Pteronura brasiliensis (Zimmerman, 1780), known as the Giant Otter, is the largest species in the subfamily Lutrinae (Mustelidae, Carnivora). According to Groenendijk et al. (2015), this species lives in calm waters of rivers, streams, lakes, and swamps of tropical forests with low altitudes and high abundance of food (fishes), and uses ravines with little inclination for refuge or dense vegetation. Pteronura brasiliensis is also an indicator of the aquatic ecosystem's health and a keystone species, as it affects the food chain at different trophic levels (Groenendijk 1998).
Two subspecies of the Giant Otter are currently recognized: Pteronura brasiliensis paraguensis (Schinz, 1821), a smaller form that inhabits the Paraná and Paraguay river basins (Pantanal) and Pteronura brasili ensis brasiliensis, a larger form that inhabits the Amazon and Orinoco river basins (Harris 1968).
Pteronura brasiliensis is one of the largest predators of tropical forests and wetlands of South America (Utreras et al. 2005), where it is endemic (Carter and Rosas 1997), and it is currently one of the most endangered mammals on the continent (Pickles et al. 2012). This species is classified as Endangered, A3ce, by the International Union for Conservation of Nature (IUCN), indicating that the global population of P. brasiliensis is estimated to decrease by 50% or more over the next 25 years (three generations) (Groenendijk et al. 2016). In Brazil, Decree nº 444/2014 of the Ministry of Environment recognizes P. brasiliensis as endangered (vulnerable category), with a reduction in the population of at least 30% over the next 20 years under current pressures (Groenendijk et al. 2016).
Current threats to Pteronura brasiliensis are related to habitat destruction through logging activities, mining, deforestation, urban growth (Carter and Rosas 1997), soil erosion, reduced abundance of prey, dredging of waterways for navigation, pollution by fertilizers and fuel, and conflicts with fishermen . Additionally, there are issues related to fishing activities, human settlement along river banks, unregulated tourism (Groenendijk 1998), domestic animal diseases, and occasional hunting .
Historically, Pteronura brasiliensis occurred in all countries of South America, except Chile. The current total wild population size is unknown and further surveys are required to determine this. Giant Otters are gradually increasing in number in some parts of their range and returning to areas where they have been absent for many years, such as Bolivia and Peru. Despite the lack of precise distribution data for this species, Check List 12(4): 1946, 9 August 2016doi: http://dx.doi.org/10.15560/12.4.1946ISSN 1809-127X © 2016 Check List and Authors

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Pacca et al. | Distribution of Pteronura brasiliensis in Roraima legs, large feet, and webbed digits, along with long and numerous facial whiskers that protrude from the nose, forehead, and temples (Duplaix 1980). In alarm situations, all group members expose their head and neck above the water, making repetitive wavering screams and growls, which is a territorial behavior (Emmons 1997; Figure 1).
Fifty-two new records of Pteronura brasiliensis were collected: 27 from direct sightings of individuals or groups and 24 from indirect sightings such as latrines, burrows, footprints, or camps ( Figure 2). Of the total records, eight colleagues from the Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio) provided 21 records, and another 31 records were collected during field expeditions undertaken by the authors of the present study.
it is believed that their population levels are low in Ecuador, Colombia, Venezuela, and in the western part of Brazilian Amazonia . In fact, it is possible that the last strongholds of P. brasiliensis are in Brazil, Guyana, Suriname, and French Guiana, although further information and studies are needed. Pteronura brasiliensis populations are generally small, isolated, or declining in most of Brazil. However, they occur in larger populations in the Pantanal and Amazon basins (Rosas et al. 2008).
Thus, the aim of this study is to present new data on the occurrence and distribution of Pteronura brasiliensis in Brazil, particularly along the upper Branco River in the extreme north of Brazilian Amazonia. We also report the first record of this species in the lavrado region, a non-forest environment in northwest Roraima.
Surveys of Pteronura brasiliensis were made in the Branco River basin in the state of Roraima in the extreme north of Brazilian Amazonia, where records of this species were unknown (Table 1). All field expeditions were made with boats travelling at an average speed of 10 km/h, allowing the sighting of animals and their tracks by applying the "stop-at-first-sign" method (Evangelista and Tosi 2015).
All direct and indirect sightings (i.e., tracks, burrows, and feces) were photographed and had their geographic coordinates collected with a Garmin™ 62s GPS receiver (datum: WGS84). To increase the number of records, we asked colleagues from the Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio) to record any sightings during field activities, enhancing the compilation of data and new records (Table 2). Moreover, we reviewed scientific literature, to search for studies that provide reliable records of this species in Roraima.
Pteronura brasiliensis is an easily recognizable species that can be confused only with the Neotropical Otter (Lontra longicaudis Olfers, 1818). However, the P. brasil iensis is much larger, reaching a mass of 35 kg and a total length of 180 cm, while the Neotropical Otter can weigh up to 15 kg and measure 130 cm in length (Eisenberg and Redford 1999). However, these statements are based only on visual observations, and a morphometric study involving a large geographical sample needs to be done in order to verify this hypothesis .
Pteronura brasiliensis also has, as its main features, white spots in the ventral portion of the neck, short   A literature review revealed that only two studies have provided precise coordinates of the distribution of Pteronura brasiliensis in the state of Roraima (Restrepo 2009;Evangelista and Tosi 2015). Evangelista and Tosi (2015) collected seven records of this species from southeastern Roraima, while Restrepo (2009) added another 13 direct sightings on the lower Branco River. Adding to the 52 records presented in this study (Figure 3), the P. brasiliensis is now known from 72 locality records in Roraima. Notably, our study increases the number of records in the state by 360%.
Despite information being available for more than 75% of the total distribution of the Pteronura brasilien sis, there are still gaps in the knowledge of this species' distribution in Brazil (Evangelista and Tosi 2015), confirming the importance of this study. Although there is great difficulty in observing P. brasiliensis in the Brazilian Amazon, particularly owing to the complex logistics in this region, this work presented the first record of this species in the lavrado ecosystem, an ecosystem of diverse non-forest vegetation types and the largest contiguous area of savannas in the Brazilian Amazon (Campos et al. 2008). Drainage networks exist in interconnections denominated as "veredas" (paths) of buritizais (meaning stands of Buriti Palm, Mauritia flexuosa L.) which are nothing more than streamsthat connect the lakes to the larger rivers (Barbosa et al. 2007) that are important to maintain the gene flow among species. This region, in northeastern Roraima, eastern Guyana, and southern Venezuela, is one of the endemic, Human occupation of the lavrado region has accelerated in a short time and requires a rapid response from public authorities for the protection this region. Among the main drivers of growth are plans to build hydroelectric dams and increase agricultural areas (Campos et al. 2008). The fact that more than half of the lavrado area of Roraima is indigenous land illustrates the fundamental role of these communities in the conservation of the region. However, according to Barbosa and Campos (2011), the growth of the indigenous population also increases human density in the area, and consequently, is a threat to the ecosystem. Thus, we highlight the urgent need to implement participatory program management and environmental monitoring in indigenous territories in this region.
Given this concern, the lavrado region needs urgent conservation measures such as the immediate creation of protected areas covering significant areas of the ecosystem to ensure the protection and study of its still unknown biodiversity. Despite its ecological importance, protected areas of lavrado are presently restricted to small natural enclaves in Estação Ecológica de Maracá (ESEC, Maracá) and Floresta Nacional de Roraima (FLONA, Roraima). Together, these two conservation units protect less than 0.5% of the entire lavrado area  (Barbosa et al. 2007).
According to Pickles et al. (2012), although Pteronura brasiliensis population has recovered in a few locations within its range, its distribution remains fragmented. It is unlikely that gene flow is currently occurring among the populations of northern South America, mostly within the lavrado area. Therefore, we recommend the re-establishment and maintenance of metapopulation connectivity that will allow for the dispersal of the species through corridors between the Orinoco, Amazon, and Guianas. It is necessary to prioritize the creation and preservation of ecological corridors that connect conservation areas in order to avoid habitat fragmentation of P. brasiliensis and the isolation of populations. This is possible by integrating protected areas with permanent preservation areas through territorial land-use planning.
For Duplaix et al. (2015), local residents are key factors in promoting the conservation of Pteronura brasiliensis. The local human population shares the rivers and the habitat with Giant Otters; encouraging participation in conservation initiatives will enhance conservation outcomes. However, this can only be achieved through education, consensus building, and alternative economic incentives.
Therefore, urgent actions for the maintenance of environmental quality and faunal and floral populations may rely on spatial planning measures, environmental monitoring, participatory planning with local communities, creation of conservation units, and especially creation of new financial incentives to relieve economic pressures to explore natural resources and encourage alternative livelihoods. These actions would ensure not only the integrity of the ecosystem, but also the maintenance of Pteronura brasiliensis populations that still need study to gain a better knowledge of their local and regional conservation status.