We provide a list of bird species for Ribeira lagoon, a protected area in Rio de Janeiro, southeastern Brazil. Data were obtained in monthly surveys in points along a continuous transect, between August 2008 and July 2009, and 21 ad libitum observations. In total, 174 species were listed, including 121 land birds and 53 waterbirds. Of these, 11 are considered threatened at regional level. Waterbird richness was significantly higher in the dry season (April to September) than in the rainy season (October to March), whereas land bird richness remained constant. However, land bird richness varied throughout the year, with the highest value in February 2009 (77 species) and the lowest in May 2009 (41 species). The species listed account for 23% of the total of 745 bird species listed for Rio de Janeiro, and for 49% of 108 waterbirds recorded for the state.
The Atlantic Forest biome is a priority area for global biodiversity concerns [
Located in northern Rio de Janeiro, Ribeira lagoon is a coastal water body recently recognized as an Area of Environmental Protection (APA). However, no management plan has been developed for this lagoon, and it has not been studied in detail. This study aims to: 1) provide an inventory of birds recorded in Ribeira lagoon along a year of systematic surveys and additional data collected during opportunistic observations; 2) test if the richness of land and waterbirds differ significantly between the dry and rainy seasons and throughout the year.
The present study was conducted in Ribeira lagoon (22˚07'12" S; 41˚27'03" W), located in Quissamã, a municipality in northern Rio de Janeiro, southeastern Brazilian coast. The study site is a 4 km2 costal lagoon surrounded by marshes and mudflats which may reach 30 km2 during the rainy season (
tween April and September) and the rainy season (between October and March) [
We carried out monthly excursions in Ribeira lagoon, between August 2008 and July 2009, comprising one complete cycle of climatic seasons and totaling 292 h of sampling efforts. Each monthly visit lasted three days. Surveys of species presence were conducted mainly between 6 am and 10 am, and 3 pm and 7 pm. More specifically, our observations were made along 20 semi-random points spaced by at least 300-m intervals along a linear transect around the lagoon. We called this “semi-random” sampling, because points were randomly chosen only in accessible locations [
Differences in richness between dry and rainy seasons were assessed with the Mann-Whitney test for median comparison. We also used the chi-squared test to observe if richness varied significantly among months [
We recorded 174 bird species during visits in Ribeira lagoon, including 53 waterbirds and 121 land birds. Of these, 14 bird species were documented exclusively during ad libitum observations. The families with high numbers of species were Tyrannidae (18), Ardeidae (12) and Emberizidae (11). Additionally, of the 174 bird species, 13 (7.5%) were long-distance migrants, of which 12 are from the Northern Hemisphere and only Tachycineta leucopyga (
Interestingly, 11 of the species recorded are considered threatened (or near/probably) in Rio de Janeiro: Dendrocygna bicolor, D. autumnalis, (
With respect to the temporal variation in species richness, the observed monthly richness varied significantly for land birds (χ2 = 36.6, P = 0.00021), but not for waterbirds (χ2 = 12.6, P = 0.32). On the other hand, median values of waterbird richness were higher in the dry season (25 species) than in the rainy season (16 species) (Mann-Whitney test, P = 0.004), in contrast to the lack of difference for land birds (Mann-Whitney test, P = 0.62). The highest richness of land birds occurred in February 2009 (77 species), while the lowest value was observed in May (41 species). Moreover, the highest richness of waterbirds occurred in September 2008 (30 species), whereas the lowest was recorded in December 2008 and January 2009 (16 species each) (Appendix 1).
The rarefaction accumulation curve reached a clear asymptote after 12 monthly surveys. The Jackknife 1 index estimated the number of species at 183 ± 6 (
Regarding temporal variation, the high richness of waterbirds in the dry season may be due to high availability of shallow waters, which are an advantageous feature considering the feeding habits of many species that occur exclusively during this season [
trations of preys consumed by waterbirds [
With respect to land birds, temporal variation occurs to a different scale. Variation takes place on a monthly basis, not between climatic seasons, indicating the intense species turnover in land bird assembly through the year. Thus, future monitoring in the region should be based on surveys carried out on a time basis, at monthly intervals, at least. Differently from our findings, Alves and Pereira [
Some species previously listed for nearby wetlands were not recorded in our study. Anas discors, a migrant species from North America, was recorded by Antas et al. [
The richness predicted by the Jackknife 1 estimator (183 ± 6 species) was slightly greater than the value observed based on both systematic and ad libitum surveys together (174 species). This result reveals the high efficiency of this estimator, considering the sampling methods in the present paper. So, this estimator can be considered a useful tool to compare richness between wetlands surveyed according to different sampling efforts [
Our results can be compared with the information available for the Restinga de Jurubatiba National Park (22˚12'03" S; 41˚28'04" W), the most similar environment recently inventoried. Alves et al. [
When compared to other lowlands exhaustively inventoried in Rio de Janeiro state, Ribeira lagoon shows higher richness. For example, a recent study in 3.80 km2 of lagoons, marshes and forest in Jacarepaguá lowlands (22˚58'53" S; 43˚22'27" W) listed 142 bird species, in contrast with the 172 recorded in Ribeira lagoon [
Regarding the occurrence of threatened birds in the study site, Dendrocygna autumnalis was previously reported by Antas et al. [
Of the total number of species recorded, Passer domesticus, Estrilda astrild and Cariama cristata were introduced. The first two originate from the European and African continents, and were introduced in Brazil in the early 1900’s, expanding their distribution ranges using their forage and reproductive skills [
The documented record of T. leucopyga represents the first for Rio de Janeiro state, and prompted the inclusion of this species in the bird list of the state [
The list of species we have provided for Ribeira lagoon includes 23% of the total of 745 bird species listed for Rio de Janeiro, as well as 49% of 108 inland waterbirds recorded for the state. In this context, the high number of species recorded, besides the eleven threatened species at state level (nine waterbirds), highlights the importance of this natural wetland. Yet, Ribeira lagoon is under intense pressure due to the digging of canals to claim land for agriculture, sewage discharges, hunting and human-induced fire, such as observed in other lagoons in northern Rio de Janeiro. Thus, further studies should evaluate waterbirds habitat use in this coastal lagoon and other similar environments, in order to improve restoration and management strategies.
The authors are grateful to the municipal authorities of Quissamã and ICMBio and to the Ecology and Natural Resources Post-graduation Program, State University of Northern Rio de Janeiro. Also, authors thank to J.F. Pacheco for kindly providing relevant literature; to A.B.A. Soares for helpful comments on the study and to G. Brito and A. Zillikens for reviewing early versions of the manuscript. This study is part of the wetland birds monitoring program in the northern coast of the Rio de Janeiro State. S. S. is supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico-CNPq (Processo no. 301544/2008-5). D.C.T. is supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior-CAPES.