Revista Brasileira de Ornitologia - Universidade Federal do Acre

More documents

Recommendations

Info

404Birds of the Brazilian state of Acre: diversity, zoogeography, and conservationEdson GuilhermeContact and hybridization zonesTwo contact zones were identified within the studyarea (Acre) based on the distribution of parapatric taxa(Table 2). I have denoted these zones as the (a) westerncontact zone and (b) eastern contact zone (Figures 5, 6,and 7). The western contact zone is based on the presenceof the following sister taxa – Pipra filicauda/P. fasciicauda(Figure 6), Dendrocincla fuliginosa neglecta/D. f. atrirostris(Figure 5), and Pteroglossus castanotis castanotis/P. c.australis (Guilherme 2009). The eastern zone is definedby the occurrence of Xiphorhynchus chunchotambo/ocellatus, Hypocnemis subflava/peruviana (Figure 7), andGlyphorhynchus spirurus castelnaudii/G. s. albigularis(Guilherme 2009).Two possible hybridization zones were identifiedwithin the study area, coinciding with the contact zones.The western hybridization zone is defined on the basis ofthe presence of specimens with intermediate characteristicsbetween Pteroglossus castanotis castanotis/P. c. australisand Dendrocolaptes certhia juruanus/D. c. polyzonus,whereas the eastern zone is characterized by the presenceof morphologically intermediate specimens betweenBrotogeris cyanoptera cyanoptera/B. c. beniensis and Momotusmomota cf. nattereri/M. m. simplex (Guilherme 2009).DISCUSSIONBird diversity in AcreThe large number of bird species recorded in theBrazilian state of Acre further emphasizes the biologicaldiversity of southwestern Amazonia (Haffer 1990). Infact, the number of species recorded for Acre – 667 –represents more than half of the total recorded for thewhole of the Amazon basin (Marini & Garcia, 2005;Mittermeier et al. 2003), and if only the fauna of thesouthern basin (south of the Solimões/Amazon channel)is considered (Stotz et al. 1996), 74.4% of the specieswere recorded in Acre.The avifauna of Acre is composed primarily ofresident species, but also includes migrants and invaders.Five of the nine new species added to the list of Brazilianbirds since 2005 were recorded in Acre (Guilherme et al.2005, Guilherme & Aleixo 2008, Aleixo et al. 2008, Regoet al. 2009, Zimmer et al. 2010, CBRO 2011). Anotherspecies – Cacicus koepckeae – should also be added to thislist, based on the recent record from the Chandless River(Buzetti 2008). Of the 1832 bird species known to occurin Brazil (CBRO, 2011), 22 have been recorded only inAcre (Appendix 1), which testifies to the singularity ofthis state. Acre is located entirely within the Inambaricenter of endemism, the largest such area in the lowlandsof the southern Amazon basin (Silva et al. 2005b).According to Cracraft (1985), the geographic rangesof the 57 bird taxa endemic to the southwestern Amazonbasin define the limits of the Inambari center. Almostthree quarters (73.6%) of these endemic taxa have beenrecorded in Acre, with four new species (all described since1985) being added to the list subsequently (Appendix 1).Acre can be considered to be an excellent sample of theInambari center, given that it covers only 12% of its area,but contains more that 70% of its endemic species. Giventhis, Acre is an excellent natural laboratory for the studyof historic biogeography.The migratory species were recorded in both of thegeographic sub-regions (Appendix 1). However, some ofthe species arriving from south-central South Americawere only observed in eastern Acre (Appendix 1). Australand intratropical migrants such as Myiopagis viridicata,Tyrannus albogularis, Casiornis rufus, and Turdusamaurochalinus, arrived in the state from the southeast(e.g., Bolivian Chaco), where they breed (Davis 1993;Jahn et al. 2002, Appendix 1). Some migratory species,in particular tyrannids, tend to occupy the forest edges,secondary vegetation, and open areas (Chesser 1997). Asthe forest cover of easternmost Acre has been extensivelydisturbed, the resulting open and regenerating habitatscontribute to an increase in the probability of recordingother forest edge species such as Micrococcyx cinereus,Contopus cinereus, and Elaenia flavogaster (Appendix 1). Itseems likely that the occurrence of these species will alsobe confirmed for the central-western sub-region of thestate as new surveys are carried out in these areas duringthe migration season.A group of species, previously known only from thefoothills of the Andes and lowlands in Peru and Bolivia,was recorded in the central eastern sub-region of Acre.For some species, such as Picumnus subtilis, Xiphorhynchuschunchotambo, and Cacicus koepckeae, these recordsdo not represent either migrations or recent shifts indistribution, but rather, these species are residents thathad simply not been recorded previously, due to thelack of surveys in the area adjacent to the borders withPeru and Bolivia. Other species, such as Conothraupisspeculigera and Pseudocolopteryx acutipennis neverthelessappear to migrate from the Pacific slope and Andes to thelowlands of Amazonia.Vagrancy also plays a role in the Acre avifauna.Phoenicoparrus jamesi, which is typical of the salt lakesof the Andean altiplano, was observed in Acre on a singleoccasion, and was considered to be an accidental visitorby Guilherme et al. (2005). The nearest record of thisspecies is from the Manu National Park in southwesternPeru, at an altitude of 350 m asl, where it was alsoconsidered to be an vagrant (Walker et al. 2006), giventhat this lowland area is equally distant from the naturaldistribution of the species (del Hoyo et al. 1992). Anotherspecies considered to be a vagrant here is HeliomasterRevista Brasileira de Ornitologia, 20(4), 2012
Birds of the Brazilian state of Acre: diversity, zoogeography, and conservationEdson Guilherme405FIGURE 6. Geographic distributions of Pipra filicauda and P. fasciicauda according to Natureserve (2007). The arrows point from the core to theperiphery of the ranges of the respective species. The red triangles and black dots indicate the parapatric occurrence, respectively, of Pipra filicauda andP. fasciicauda in western Acre.FIGURE 7. Geographic distribution of the parapatric species Hypocnemis peruviana and H. subflava in eastern Acre showing the estimated “secondarycontact zone”. The arrows point from the core to the periphery of the ranges of the respective speciesRevista Brasileira de Ornitologia, 20(4), 2012
Page 2: Revista Brasileira de OrnitologiaED
Page 7: Revista Brasileira de Ornitologia,
Page 10 and 11: 396Birds of the Brazilian state of
Page 25 and 26: Birds of the Brazilian state of Acr
Page 58 and 59: 444First record of Augastes scutatu
Page 60 and 61: 446First record of Augastes scutatu
Page 62 and 63: 448Records of the Crowned Eagle (Ur
Page 64 and 65: 450Records of the Crowned Eagle (Ur
Page 66 and 67: 452Predation of Long-tailed Silky F
Page 68 and 69:
454First record of the Chaco Earthc
Page 70 and 71:
456A first documented Brazilian rec
Page 73 and 74:
Revista Brasileira de OrnitologiaIN
Page 76:
Revista Brasileira de OrnitologiaVo
show all

Revista Brasileira de Ornitologia - Universidade Federal do Acre

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?