Diversity and conservation of birds associated with an urban landscape in the southwest Brazilian Amazon

The Amazon presents an arc of deforestation which has expanded into natural areas and bird community studies in these areas are incipient for urban landscapes after transformation. Therefore, the bird community in an urban landscape in the southwest Amazonian region within an area in the arc of deforestation was investigated. The observations were performed through linear transects, during the wet and dry seasons of 2013. Records were obtained using binoculars and cameras. A total of 191 species of birds were recorded. The species accumulation curve was not reaching the asymptote, showing that new species can be recorded with a sampling effort increase. The community has low richness as a result of pressure on Amazonian environments and a high degree of anthropization. However, there is relevant composition, because nectarivores, insectivorous, carnivores, omnivores, and granivores were found in all environments, as well as endemic and threatened species.


Introduction
The composition of the bird community is related to the landscape (MARTIN, 1985;ROTH, 1976) and intrinsic factors which are constantly changing. In the south of Amazon, this change is due to the increasing agricultural areas, pastures, road creation (DAVENPORT et al., 2017;FERRANTE;FEARNSIDE, 2020), hydroelectric plants (FEARNSIDE, 2019), and later increasing urban agglomerations (CÔRTES; SILVA-JUNIOR, 2021), forming the arc of deforestation.
The region of the municipality of Juina is located in the amazon deforestation arc, in the middle portion of the Aripuanã and Juruena rivers, which are included in the Madeira Brazilian Shield and Tapajós-Juruena ecoregions (WWF; TNC, 2015). This area presents recent deforestation, with higher intensity occurring after 2000 (see methods in CASSATI et al., 2020). There is a lack of knowledge of the bird community for the region, with few reports of birds being used to feed the indigenous community (COIMBRA, 1985).
One of the factors that most threatens bird diversity is the forest fragmentation process due to urbanization, as this environment does not return to its previous conditions (MARZLUFF;EWING, 2001), and this process gradually accompanies the growth of the human population (MEYER; TURNER, 1994) and all its impacts.
The number of studies of birds in urbanized environments has become increasingly common, mainly due to the expansion of these environments over tropical forests (e.g., VASCONCELOS et al., 2013 andVOGEL et al., 2016 to Atlantic Forest;AVILLA et al., 2021 andRICO-SILVA et al., 2021 to Amazon), showing that the bird community persists through behavioral and morphological flexibility to increase a population's ability to cope with anthropogenic hazards (AVILLA et al., 2021). Therefore, the objective of this report is to describe and analyze the bird community in

Material and methods
The study was conducted in Juína city, northwest of Mato Grosso State, northern Brazil, in the Brazilian Amazon (11°26'49"S; 58°43'21" W, 315 m high). Juína spans more than 25,000 km² and has approximately 40,000 inhabitants. The economy is based on industrial and agricultural exploitation (IBGE, 2018). The climate is AW according to the Köppen classification (ALVARES et al., 2013).
Each sampling area was performed twice by day and the observations occurred from 6 am to 9 am and 3 pm to 6 pm, ten days by month nonsequential, in the wet (January to March) and dry (June to August) seasons of 2013. Five sampling areas were chosen for observations (Figure 1), in which one linear transect of 500 m was determined, with an active search for animals, the presence of hearing, and viewing points of specimens. The areas were chosen because they include forest remnants, riparian forests, anthropized areas (abandoned pastures by five years), and environments under the influence of rivers (Table 1).
Regarding the study areas, point one is composed of a pasture area with approximately five years of abandonment, with the presence of plants in the shrub, herbaceous and arboreal strata of approximately 10 meters in height. Point two is formed of a secondary Amazonian Forest with low human intervention. The trees reach an altitude of approximately 30 to 35 meters and the forest is approximately 100 meters away from the riparian forest. Point 3 is formed by a lake surrounded by shrubby and herbaceous vegetation. Points 4 and 5 are formed by riparian forests that accompany the main stream that crosses the municipality of Juína.
Valid bird species records were considered when the species were heard or seen within each area (ALEXANDRINO et al. 2016;UEZU et al. 2005). Records were obtained using Nikon 8 x 40 binoculars. We used a Canon EOS REBEL T1i camera to help record/sight the birds. The nomenclature used followed Piacentini et al. (2015) and conservation status followed the IUCN proposal.
A species accumulation curve to verify the sample sufficiency was generated using the EstimateS 7.0 program (COWELL, 2006) with 1000 randomizations, and the first-order Jackknife richness estimator was used, most common for matrices with low numbers of species records (BURNHAM; OVERTON, 1978). The similarity between sampling areas was obtained by the Jaccard index (VALENTIN, 2000) and the UPGMA method using the Primer & Permanova v.6 software program (ANDERSON, et al. 2008;GORLEY, 2006).

Results
A total of 191 species of birds were recorded (Table 2), allocated into 56 families, with the most representative families being Tyrannidae (16), Thraupidae (N = 16), Psittacidae (N = 15), and Accipitridae (N = 14). The species accumulation curve did not reach an asymptote, suggesting that other species will be registered with an increase in the sampling effort. The firstorder Jackknife richness estimator showed that the area's richness is 230.6 species (Figure 2), so this study recorded 82.83% of the total diversity.
The similarity cluster and grouping between sampling areas demonstrated that sampling areas 1 and 2 have a similarity of 60%, while areas 4 and 5 were 72%, and area 3 had only 22% similarity compared to the other four areas ( Figure 3). These results were already expected, as the landscapes of areas 1 and 2 are very similarly composed of anthropogenic areas, and areas 4 and 5 are composed of preserved Amazonian riparian forest areas. Area 3 is totally dissimilar from the others, being composed of lower-elevation swamp and lake areas.
The composition of the community in areas 1 and 2 includes birds that occur in both forested and anthropogenic areas, and even in other biomes in Brazil such as C. squammata, P. cayana, and M. candidus. Areas 4 and 5 are composed of specialist Amazonian species, even though they are located in an urbanized region, and among these representatives we can highlight: A. weddellii, P. snethlageae, P. tuberosa, and O. hoazin, among others. Area 3 is composed of specialists from aquatic and riparian environments, some of which are widely distributed in Brazil with similar landscapes, such as N. dominicus, A. cocoi, P. ajaja, and H. fulica. There were no significant variations in the community between the two seasonal seasons.    Source: the authors.

Discussion
Six species are threatened. We emphasize that the species classified in the "vulnerable" category are endemic to the Amazon region, and this status refers to their restricted occurrence area and the progress of deforestation (CARRERO et al., 2020).
It is interesting to highlight that the threatened birds present in this study (R. tucanus, P. perlata and P. snethlageae) are species that have an ecology closely associated with the Amazon domain, occurring exclusively in this biome, showing the fragility of some elements of this bird community, that have other endemic species of the biome that are not yet in population decline or threatened, however, may in the future fall into some category of threat.
The avifauna richness is low as probably a result of pressure on Amazonian environments and the high degree of anthropization since some inventories found between 342 to 796 species (BEJA et al., 2009;BORGES et al., 2001;HENRIQUES et al., 2003) for other Amazonian areas. However, the representativeness of the records of this study stands out, as it corresponds to an approximate richness of 10% of the species described for the country (PIACENTINI et al., 2015).
Considering the proportion of species, the trophic structure did not vary between environments, since nectarivores, insectivorous, carnivores, omnivores, and granivores were registered in all sampling areas. However, it is worth noting that there is an absence of records of large predators which are common in the northern region of Brazil, such as Harpia harpyja (MOURA et al., 2012). However, this fact might be related to the disturbance degree that the studied area has been suffering (urbanization), since H. harpyja is considered an indicator species of little disturbed landscapes (ALBUQUERQUE, 1995).
Four records of this study can be considered remarkable, namely that of S. ornatus, because in addition to being a near-endangered species (IUCN, 2020), it is considered rare in almost all Brazilian states (MENDONÇA-LIMA et al., 2006), even though it is not yet on the world and national lists (MMA, 2014) of species threatened with extinction. In addition, the recently described P. snethlageae is considered to be endangered in the "vulnerable" category (IUCN, 2020), as well as P. jacquacu and D. accipitrinus which are endemic species in the Amazonian domain (SICK, 1997); due to their occurrences being restricted to this biome, they may be suffering anthropogenic pressures in the future due to the replacement of natural vegetation by soy cultivation areas, illegal logging, fragmentation and urbanization (MARGULIS, 2003).
We emphasize that studies in areas such as the one herein are extremely important, as conservation and management can play an important role in the maintenance of the entire ecosystem, enabling the dispersal of species and maintaining the biological flow in urban matrix areas (ARAUJO et al., 2018).
Although there is a lack of characterization in the study area due to fragmentation and urbanization, the richness of the bird community is low as a result of pressure on Amazonian environments and the high degree of anthropization; however, some species occurring in the region which are more specialized were not registered in the present study.

Conclusions
Despite the wide lack of characterization suffered in the study area due to fragmentation and urbanization, the community of birds is low, as a result of pressure on Amazonian environments and the high degree of anthropization. This research can fill the knowledge gap about birds in the region because there are no previous studies on Revista Agrogeoambiental, v.14, e20221692, 2022 avifauna in this location and even in this Amazon region, thus contributing to future Conservation Biology projects. New studies are suggested because the list of species (communities) is not static, but dynamic due to the changes in the landscape promoted by human actions.