Celine de Melo

Avian frugivory in Miconia (Melastomataceae): contrasting fruiting times promote habitat complementarity between savanna and palm swamp

Species of Miconia are considered keystone plant resources for frugivorous birds in Neotropical forests, but for other ecosystems little of their ecological role is known. The fruiting phenology and the composition of frugivores of four Miconia species in savanna and palm swamp from the Brazilian Neotropical savanna were studied in three sites from November 2005 to May 2011. The hypothesis tested was that plants from different habitats share their frugivores and consequently promote links between habitats. Through focal plant observations (30-50 h per species in each site), 668 visits by 47 species of birds were recorded and plants from different habitats shared most of the frugivores (49-97%). The fruiting of Miconia chamissois in the palm swamp during the period of fruit scarcity (dry season) was accompanied by an enhancement in the frugivore bird richness and abundance in this habitat, providing indirect evidence of resource tracking. Bird species which primarily dwell in savanna recorded consuming fruits in palm swamps during the resource-scarce season is taken as evidence of landscape supplementation. Miconia assemblage studied here seems to promote a link between two adjacent habitats in the Neotropical savanna from Central Brazil, a link which is likely to be common in this naturally patchy ecosystem.

Ticks on birds in a savanna (Cerrado) reserve on the outskirts of Uberlândia, Minas Gerais, Brazil

We report tick infestations on birds, in the environment and on domestic animals in a non-forested phytophysiognomy, the savanna-like Cerrado sensu stricto, in a natural reserve on the outskirts of the urban area of Uberlândia, Minas Gerais, Brazil. Overall, 238 birds within 50 species, 15 families and six orders were caught. Passeriformes were the most numerous, with 216 birds (90.75%), among which 22 had ticks (n = 31). Within this order, the prevalence of tick infestation was 10.2%, and the abundance and mean intensity were 0.14 and 1.41, respectively. Only immature ticks of the species Amblyomma nodosum were found on the birds. The tick species found both on animals (Rhipicephalus sanguineus, Rhipicephalus (Boophilus) microplus, Amblyomma cajennense and Dermacentor nitens) and in the environment (Amblyomma dubitatum, Rhipicephalus (B.) microplus and Amblyomma cajennense) were as expected. This difference in tick species between the environment and birds possibly occurred because the sampling of the environment was limited to the ground. This study also highlights the importance of the diverse microenvironments used by ticks and hosts in the same area and the complex ecology of bird-tick relationships. Ecological and epidemiological aspects of the findings are discussed.

Plastic responses in tree architecture and specific leaf area of Xylopia aromatica (Annonaceae): adaptations to environments with different light intensities

The capacity of plants to occupy different environments is made possible by the plastic responses they present in heterogeneous environments. Light directly influences the plastic responses of plant functional traits, mainly involving leaf traits (specific leaf area and leaf dry matter content). Our objective was therefore to evaluate the phenotypic plasticity of Xylopia aromatica, a heliophilous species occurring in two physiognomies: cerrado sensu stricto (savanna—high light intensity environment) and Cerradão (woodland savanna—shaded environment). It is expected that trees growing in Cerradão will present adaptations that reduce self-shading and optimize their photosynthetic capacity. We sampled 40 trees (20 in each physiognomy) and collected seven parameters of tree architecture and specific leaf area (SLA) of these individuals. We found that in Cerradão, a closed and shaded physiognomy, X. aromatica showed significantly more cylindrical trunks, greater overall height, first branch height and SLA, and a lower crown length ratio. This differentiation can be defined as a plastic phenomenon, likely related to the higher efficiency of light interception and absorbance by trees and beyond to reduce self-shading in Cerradão. The plastic response of X. aromatica showed in this study is potentially a strong explanation for the adaptive success of cerrado plant species in different environments.

Frugivory and potential of birds as dispersers of Siparuna guianensis

Siparuna guianensis is a neotropical tree species, found both on edge and interior of forest fragments, mainly on understory and regeneration areas. The fruit are zoochorous with a sweet aril. This work aims to determine the bird species that eat the fruits of S. guianensis in a semi deciduous forest fragment in Brazilian Cerrado and measure which species have the highest potential as seed dispersers. Seven individuals of S. guianensis were sampled, totaling 69 hours. A hundred and fifty four visits were registered by seven species of birds. Antilophia galeata had the biggest potential as seed dispersal agent. Antilophia galeata, Lanio penicillatus and Dacnis cayana can be important seed dispersers, since they have a high consumption and visitation rate. The consumption of S. guianensis by species of different feeding guilds can be an important strategy for dispersal of plant species in regeneration habitats, raising the chances of an effective dispersal.

Overlap and resource sharing in coteries of fruit-eating birds

A range of species eating the same fruit suggests that niche overlap can occur, along with potential competition among them. To test if the overlap in the coterie of fruit-eating birds is larger than would be expected by chance, we performed a comparison with coteries generated from the use of null models. The study was carried out in an area of savanna woodland of 127 ha in Uberlândia city, Brazil. Four individuals of five zoochorous plant species were selected and 60 h of focal observation was performed on each species. We recorded species of birds that consumed fruits and the quantity of fruit removed. We used an index of Proportional Similarity (PS) between each pair of plant species, using the relative proportion of fruit taken by each bird species of each plant. The mean value of observed PS was compared with the mean PS generated from randomizations. Thirty-six bird species were recorded eating fruits in the selected plant species. The mean overlap observed (PS = 0.183) was significantly higher (P = 0.032) than the mean overlap generated by the null models (PS = 0.123). This pattern suggests that competition is not an important factor in the formation of the coteries and there is sharing of resources. The abundance of fruits offered, especially in the rainy season, and the relatively low number of frugivorous species may be factors explaining the low influence of interactions and therefore the overlap between coteries.

Modularity in ecological networks between frugivorous birds and congeneric plant species

Ecological and evolutionary factors influence the presence of modules in species interaction networks, and these modules usually cluster functional similar species. But whether closely related species form modules is still unknown. We tested whether the interaction networks formed by frugivorous birds and Miconia plants are modular and evaluated how modules were divided. To do so, we gathered from the literature data concerning four networks of Miconia and their frugivorous birds (three from Brazilian savanna and one from a rain forest in Panama). We quantified modularity using binary and weighted algorithms and also tested the relationship between bird traits (body mass, dietary specialization, migratory behaviour and phylogeny) in relation to within- and among-module connectivity indices ( c and z values). If considering only binary information, networks did not present distinct modular structure. Nevertheless, by including interaction strength, modules can be detected in all four Miconia- bird networks. None of the bird traits, however, was related with the connectivity indices. The possible fluctuation of frugivorous bird abundance coupled with the asynchronic fruiting period of Miconia might favour the formation of temporal modules comprising birds and plant species with phenological overlap, ensuring seed dispersal and facilitating the coexistence in sympatry. Bird traits had little effect on the role that each species plays within the modular network, probably because the frugivorous assemblages were dominated by small-bodied and opportunistic species.

Richness, composition and detectability of Psittacidae (Aves) in three palm swamps of the Cerrado sensu lato in central Brazil

Los objetivos de este estudio fueron: (1) investigar la riqueza y la composicion de pstacidos en pantanos, (2) determinar si el tamano de los grupos varia estacionalmente, (3) comparar las especies de acuerdo con sus tasas de detectabilidad. Ensambles de psitacidos han sido observados entre noviembre de 2006 y noviembre de 2007 con visitas quincenales en cada area a traves de observacion de punto fijo. Un total de 1616 individuos de ocho especies fueron registrados en 199 contactos. Los pantanos fueron muy similares (H > 0.62), y su diversidad de Psittacidae fue 1.56. Brotogeris chiriri ha sido considerada residente en los tres pantanos estudiados (Fr > 60 %). Aratinga leucophthalma y Orthopsittaca manilata fueron las especies mas abundantes en las tres areas. La mayoria de las especies (n = 5) fueron mas abundantes en una de las estaciones. Las especies mas abundantes en la epoca de lluvias fueron A. leucophthalma y B. chiriri (42.16 ± 30.77 individuos), mientras que en la estacion seca la mayor abundancia fue O. manilata (68.50 ± 39.35 individuos). La tasa de detectabilidad mas alta fue de B. chiriri, lo que demuestra las diferencias entre las especies y la necesidad de adaptar los metodos de investigacion para esta familia.

Dominant frequency of songs in tropical bird species is higher in sites with high noise pollution

The structure and organization of acoustic signals arise through evolutionary processes and adaptive pressures on each species. During learning, natural or anthropogenic factors, such as high noise levels in urban areas, pose challenges to acoustic communication in birds. Many species adjust their acoustic signals to higher noise levels by increasing the frequency of vocalizations. The objectives of this study were to compare the dominant frequency of songs among birds dwelling in forest fragments distant from and near to urban areas, establish correlations between the dominant frequency of song and noise levels in these environments and verified the difference of response between oscines, suboscines and non-passerines. We recorded vocalizations of birds between July/2013 and November/2014 in four forest fragments, two of them near and two distant from urban areas. We used Audacity software to measure the dominant frequency. We measured the ambient noise by a calibrated sound pressure level meter in decibels (dBA) in each of the forest fragments. We analyzed 3740 vocalizations of nine tropical bird species. Forest fragments near to urban areas have higher noise levels than more distant forest fragments. Eight of nine studied species presented higher dominant frequencies of songs in forest fragments near to urban areas. Only one species, Myiothlypis flaveola, did not change the dominant frequency of song between the four analyzed forest fragments. The difference in dominant frequency between the forest fragments distant and closer to the urban areas did not vary between oscines, suboscines and non-passerines. Eight tropical birds exhibited higher dominant frequencies of song in forest fragments near urban areas with high level of ambient noise. Oscine, suboscine and non-passerine showed song variations. Bird species that have differences in the vocalization dominant frequency can be used in environmental monitoring and in ethological studies, as they are sensitive to high noise levels. Noise pollution caused by the vehicular traffic and urbanization are correlates with changes in the vocalization of tropical birds in forest fragments.

Male Helmeted Manakins (Antilophia galeata) with more colorful crowns have better body conditions

ABSTRACT Bird plumage coloration is an important signal used in communication and may indicate individual fitness. We tested the hypothesis that coloration is related to body condition in male Helmeted Manakins (Antilophia galeata). Fourteen adult males were captured in a forest fragment in Brazilian Cerrado from November 2007 to June 2008. Crown feather coloration (brightness, hue, and saturation) was evaluated through spectrophotometry, and body condition was measured via the Relative Mass Index (RMI). Coloration characteristics were positively correlated with body condition, indicating that individuals with higher body conditions have brighter and more saturated feathers, and therefore, can use these traits to signal their good body condition.