Birds of Sete Cidades National Park, Brazil
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Cotinga 35 Birds of Sete Cidades National Park, Brazil: ecotonal patterns and habitat use Marcos Pérsio Dantas Santos, Leonardo Moura dos Santos Soares, Fábio de Macedo Lopes, Sílvia Tereza de Carvalho, Marcelo de Sousa e Silva and Douglas Danilo dos Santos† (in memoriam) Received 7 November 2011; final revision accepted 3 September 2012 Cotinga 35 (2013): OL 48–60 published online 10 March 2013 O Parque Nacional de Sete Cidades (PNSC) é uma das poucas unidades de conservação no Brasil que possuem dentro de seus limites áreas de transição ecológica envolvendo dois dos principais biomas brasileiros: Cerrado e Caatinga. Portanto é um excelente laboratório natural para estudos que envolvam a dinâmica da biota em áreas ecotonais. Durante o período de agosto de 2002 a julho de 2009 estudamos a avifauna presente nos diversos hábitats existente no PNSC afim de se avaliar a dinâmica das comunidades de aves presentes na área. Como resultados foram registradas 238 espécies de aves, pertencentes a 57 famílias. Apesar do parque apresentar estrutura florística e fisionômica do bioma Cerrado, foram registradas apenas dois espécies endêmicas desse bioma, enquanto outras cinco endêmicas da Caatinga estão presentes no Parque. A maioria das espécies registradas no PNSC é independente de formações florestais. Isso sugere que no geral a avifauna registrada no PNSC, apesar de predomínio de vegetação típica do Bioma Cerrado, reflete uma comunidade típica da Caatinga, mas com a presença de espécies dois biomas. A avifauna presente no parque pode ser classificada em dois grandes grupos ecológicos, um grupo relacionado a formações arbóreas (floresta semidecídua, mata de galeria e cerradão) e outro relacionado a formações herbáceas arbustivas (campo limpo, cerrado típico e cerrado rupestre). De um modo geral o PNSC desempenha um papel importante na manutenção de uma comunidade de aves extremamente peculiar principalmente por representar uma área de transição ecológica entre dois dos maiores biomas brasileiros, o que a torna importante não só do ponto de vista biológico, como também do ponto de vista biogeográfico. The state of Piauí, in north-east Brazil, lies within transition zones, despite that many such ecotones a unique ecological transition zone between three have suffered intense anthropogenic impacts. principally or uniquely Brazilian biomes, Amazonia, Degradation of these areas impedes the systematic Cerrado and Caatinga1,26. This configuration results understanding of ecological and historical processes in a complex mosaic of vegetation types, ranging that have moulded their communities. However, from xeric Caatinga, through mesic Cerrado to one outstanding example of a transition zone more humid habitats such as babaçu Orbignya that has been little impacted is northern Piauí’s phalerata forests and semi-deciduous rainforest Sete Cidades National Park (SCNP), which at the periphery of the Amazonian Hylea7,22. This encompasses the Caatinga–Cerrado ecotone, and diverse environment supports a variety of plants provides an excellent natural laboratory to analyse and animals from all three biomes, with varied ecological factors that determine the composition interspecific relationships and niche partitioning. and dynamics of the communities inhabiting For example, in the Caatinga–Cerrado transition these areas. The present study focuses on three zone in the south of the state, Santos28 found bird main questions: (i) the composition of the avian species typical of the Cerrado to be restricted community of Sete Cidades National Park; (ii) the to plateaux summits, whereas Caatinga species distribution of these species in an area of ecological occurred only in valleys and lowlands. Thus, while transition, and (iii) the dynamics of this avifauna the two groups occur in the same zone, they are within the mosaic of habitat types inside the park. highly segregated ecologically. The Cerrado and Caatinga biomes share much Study area and Methods of their recent history, having endured major Sete Cidades National Park (SCNP) is situated in the transformations in the Quaternary, reflected in state of Piauí (Fig. 1), between the municipalities of the composition of their respective faunas2,6,12,41. Piracuruca and Brasileira (04°05’–04°15’S 41°30’– Consequently, detailed study of the characteristics 41°45’W). This region coincides with the transition of the transition zone between these biomes can between the Cerrado and Caatinga biomes. Climate provide the key data to understanding ecological is semi-arid equatorial, with a six-month dry relationships between their biotas. season. Mean annual temperatures range from In the Neotropics, however, few data are 24°C to 26°C, with mean annual precipitation of available on the ecological dynamics of such 1,000–1,250 mm. 48 Cotinga 35 Birds of Sete Cidades National Park, Brazil Figure 1. Location of Sete Cidades National Park in the Brazilian state of Piauí. With an area of 6,221 ha and a 40-km perimeter, has a sparser understorey and a better-developed SCNP encompasses a series of sedimentary basins arboreal layer, with straight-trunked trees up to 7 at altitudes of 100–300 m16. Some 22 freshwater m tall, typically with thin, relatively smooth bark. springs occur within the park, giving rise Gallery forest (Gf) comprises narrow strips of to watercourses lined by marshes and gallery forest at the margins of rivers and streams. This forest. Oliveira22 classified the park’s vegetation is the least common forest habitat in the park. in three functional categories: forests, savannas The canopy is irregular, varying from 8 m to 12 and grassland. The same author recognised six m, with abundant palms and lianas, a herbaceous distinct habitat types within these three categories: understorey and a dense layer of leaf litter. In the open grassland, savanna, rocky savanna, savanna wet season, the water table rises above the soil woodland, gallery forest, and semi-deciduous scrub surface, gradually subsiding in the dry season. Leaf forest22. litter accumulates from leaf fall within the habitat Open grassland (Og) is a predominantly and horizontal transport from adjacent habitats. herbaceous formation, with vegetation up to 1.5 Dry forest (‘semi-deciduous scrub forest’) (Df) is m tall, and a predominance of plants belonging a relatively dense habitat with trees up to 9 m tall to the Gramineae, Leguminosae, Asteraceae and and abundant shrubs in the understorey. There is Amaranthaceae. Savanna (Sv) typically comprises no herbaceous stratum or epiphytes, but abundant two main strata, a low-lying herbaceous-shrubby lianas, both in terms of individuals and species. layer and a taller arboreal stratum, reaching up to Seasonally flooded pools (Sp) form during the wet 5 m tall. The latter is composed of small, irregularly season, in January–May. shaped trees with misshapen branches and dense, The present study was conducted between ridged bark, characteristic of the central Brazilian August 2002 and July 2009. Fifteen field excursions Cerrado. This is the commonest vegetation type in were made, each of mean duration four days, with the park. Rocky savanna (Rs) possesses a unique an overall total of 75 days of data collection in flora, characterised by relatively small plants up SCNP. Survey periods were: 8–15 August 2002, to 2 m tall and well adapted to dry conditions. This 12–19 September 2003, 9–12 April 2004, 23–26 vegetation occurs among outcrops of sedimentary July 2004, 13–16 May 2005, 7–10 April 2006, 25–28 and ferruginous rocks. Savanna woodland (Sw) August 2006, 9–13 May 2007, 11–16 October 2007, is the commonest arboreal habitat within the 8–11 February 2008, 2–5 May 2008, 24–27 October park, where it is almost always contiguous with 2008, 5–9 February 2009, 3–7 April 2009 and semi-deciduous scrub forest. It is similar to Sv, but 24–28 July 2009. Both visual and aural records of 49 Cotinga 35 Birds of Sete Cidades National Park, Brazil Figure 2. Non-metric multidimensional scaling for bird communities in SCNP, using data in the presence / absence form. Habitat: (Og) open grassland, (Rs) rocky savanna, (Sv) savanna proper, (Sw) Savanna woodland, (Gf) gallery forest, (Df) dry forest and (Sp) seasonal pools. birds in the study area were also collected during taxidermized, or fixed in formaldehyde and then periods other than these surveys, to maximise conserved in ethanol. The carcasses of all of the sampling effort. Data were collected using four taxidermized specimens were fixed and conserved complementary approaches. in ethanol. Tissue samples (muscle, liver and Visual records: systematic observations blood, when possible) were also collected from all preferentially conducted during mornings (05h00– specimens, as well as biometric data (total length 11h00) and afternoons (16h00–18h00) to ensure the and mass). The in vivo coloration of the bare parts recording of both diurnal and nocturnal species. was also noted on the specimen labels. Specimen Observers walked pre-existing trails and roads collection was authorised by IBAMA through within all six habitats at SCNP. special license DIREC 026/2007 (process no. Aural records: birds were also identified by 02001.006754/06-92) and specimens are deposited their vocalisations, which were recorded using a at the Museu Paraense Emílio Goeldi, Belém, Pará. Sony TCM 5000EV tape recorder and a Sennheiser The degree of dependence of species on ME-66 shotgun unidirectional microphone; forested habitats in SCNP was evaluated using when necessary, playback was used to stimulate three categories: (1) Independent = found only in additional vocalisations. If identification could not open habitats (Og, Sv, Rs); (2) Semi-dependent = be achieved in the field, recordings were compared recorded in at least one open (Og, Sv, Rs) and one with those held privately or in public collections. forested habitat (Sw, Gf, Df); (3) Dependent = only Mist-netting; birds were captured using in forested habitat (Sw, Gf, Sf). In addition to field mist-nets (12 m × 2.5 m; 36-mm mesh) set in the observations, data on habitat use were obtained undergrowth in a linear sequence, to avoid overlap from Silva31,33.