Revista Brasileira de Ornitologia - Universidade Federal do Acre

Birds of the Brazilian state of Acre: diversity, zoogeography, and conservationEdson Guilherme409The hybridization zone of eastern Acre is supportedby the observation of transitional forms of the taxaBrotogeris cyanoptera cyanoptera/beniensis and Momotusmomota simplex/cf. nattereri. The existence of the westernzone was supported only by the taxa Pteroglossus castanotiscastanotis/australis. In this case, the specimen MPEG26747 from the upper Juruá, which was originallyclassified as P. c. australis by Novaes (1957), presentsplumage traits and external morphology, such as the billcolor and shape, that appear to be intermediate betweenP. c. castanotis and P. c. australis. In addition to these twotaxa, it seems likely that other transitional forms may existbetween Dendrocolaptes certhia juruanus and polyzonus,given that they both occur within the same region. As thepresent study did not include the most modern analyticaltechniques available (e.g., molecular genetics andvocalization analyses), the two principal hybridizationzones identified here were considered to be “probable”rather than definitive. Obviously, the confirmation ofthe status of these zones will depend on the collection ofmore detailed data, derived from more extensive surveysusing alternative scientific approaches.Haffer (1987, p. 140) presented a map showinga wide hybridization zone that begins in the foothillsof the Andes, in northeastern Peru, and extends as faras the Amazonian lowlands, crossing the upper Juruáin Acre, which corresponds exactly to the westernhybridization zone identified in the present study. Eventhough Haffer (1987) did not provide informationon the taxa supporting his southwestern Amazonianhybridization zone, the parapatric distribution oftaxa such as P. c. castanotis and P. c. australis, andDendrocolaptes certhia juruanus and polyzonus in westernAcre provide some additional evidence for the existenceof this hybridization zone.ConservationAcre is covered almost entirely by Amazonianrainforest (Acre 2000), although 11% of its originalforest cover has been lost as a consequence of recenthuman activities in the region (Souza et al. 2006). Evenso, Acre is still one of the least deforested of BrazilianAmazonian states (Fearnside 1993). One of the principalreasons for this has almost certainly been the creation andconsolidation of a wide network of protected areas, whichnow covers almost half of the state’s territory (Acre 2000).The identification of taxa that only occur in habitatsthat are either under-represented or non-existent in thestate’s protected areas pointed clearly to two main gaps inits conservation coverage: the campinas and campinaranasof westermost Acre and the dense lowland rainforests ofthe extreme eastern portion of the state.The campinas and campinaranas of western Acremust be protected not only because these habitats arenot represented adequately in any of the state’s protectedareas, but primarily because some bird species are onlyfound in these habitats (see Guilherme & Borges 2011).The creation of protected areas within the dense rainforestof easternmost Acre is strongly encouraged due to thepresence of taxa associated specifically with this type ofhabitat, such as Lepidothrix coronata exquisita. Other taxawith similar distributions include Brotogeris cyanopterabeniensis, Momotus momota simplex, and Hemitriccusminor. These zoogeographic considerations are furtheremphasized by the fact that eastern Acre dense lowlandrainforests are within the most densely-populated partof the state, which has suffered high deforestation rates(Acre 2000).Priority areas for new ornithological surveysBirds are considered to be the best known and mostadequately sampled vertebrate group in the Amazonbasin. Even so, many areas have yet to be explored byornithologists, and represent gaps in our knowledge onthe region’s avifauna (Oren & Albuquerque 1991). InAcre, the areas with the best ornithological samplingto date are the Alto Juruá Extractivist Reserve and theSerra do Divisor National Park, located in the westernpart of the state, and the Rio Acre Ecological Station andChandless National Park in the eastern sub-region. Allother areas are either under-sampled, or have never beenvisited by ornithologists (Figure 3). The primary factorlimiting the number of surveys is the logistical difficultiesof visiting these remote areas, which can only be reachedonly by river or, in some cases, only by plane. The humanpopulation density of these areas is extremely low, andthere is very little infrastructure.Given the current situation, the following areascan be considered to be of the highest priority for futureornithological surveys in the Brazilian state of Acre:Western sub-regiona) Enclaves of campina and campinarana in themunicipalities of Cruzeiro do Sul, MâncioLima, Porto Walter, and Marechal Taumaturgo;b) Interfluvium of the Liberdade-Gregório rivers;c) Interfluvium of the Muru-Tarauacá rivers;d) Interfluvium of the Envira-Purus rivers;Eastern sub-regiona) Areas surrounding the town of Santa Rosa doPurus, on the Brazil-Peru border;b) Interfluvium of the Caeté-Iaco rivers;c) Dense rainforests of the municipalities ofSenador Guiomard, Plácido de Castro, andAcrelândia.Revista Brasileira de Ornitologia, 20(4), 2012