Tadeu J. Guerra
Universidade Federal de Minas Gerais
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Featured researches published by Tadeu J. Guerra.
Revista Brasileira De Zoologia | 2006
Charles Duca; Tadeu J. Guerra; Miguel Ângelo Marini
Territory size is an important ecological attribute of populations that has been considered a factor determines population density. Antbirds is a large group of mainly insectivorous Neotropical passerines, usually well represented in bird communities from forested landscapes in Neotropical region. Territory sizes for three Antbirds, Thamnophilus caerulescens (Vieillot, 1816) (Variable Antshrike), Dysithamnus mentalis (Temmink, 1823) (Plain Antvireo) e Pyriglena leucoptera (Vieillot, 1818) (White-shouldered Fire-eye), were mapped and their area estimated by the convex polygon method in a 50 ha forest fragment, in southeastern Brazil. The three species presented small territories of similar sizes ( T. caerulescens > D. mentalis). We failed to find any effect on territory size for the three species associated with forest edge or distance to the dirt road.
PLOS ONE | 2016
Fernanda Vieira da Costa; Marco A. R. Mello; Judith L. Bronstein; Tadeu J. Guerra; Renata de Lara Muylaert; Alice Carvalho Diniz Leite; Frederico de Siqueira Neves
Ant-plant associations are an outstanding model to study the entangled ecological interactions that structure communities. However, most studies of plant-animal networks focus on only one type of resource that mediates these interactions (e.g, nectar or fruits), leading to a biased understanding of community structure. New approaches, however, have made possible to study several interaction types simultaneously through multilayer networks models. Here, we use this approach to ask whether the structural patterns described to date for ant-plant networks hold when multiple interactions with plant-derived food rewards are considered. We tested whether networks characterized by different resource types differ in specialization and resource partitioning among ants, and whether the identity of the core ant species is similar among resource types. We monitored ant interactions with extrafloral nectaries, flowers, and fruits, as well as trophobiont hemipterans feeding on plants, for one year, in seven rupestrian grassland (campo rupestre) sites in southeastern Brazil. We found a highly tangled ant-plant network in which plants offering different resource types are connected by a few central ant species. The multilayer network had low modularity and specialization, but ant specialization and niche overlap differed according to the type of resource used. Beyond detecting structural differences across networks, our study demonstrates empirically that the core of most central ant species is similar across them. We suggest that foraging strategies of ant species, such as massive recruitment, may determine specialization and resource partitioning in ant-plant interactions. As this core of ant species is involved in multiple ecosystem functions, it may drive the diversity and evolution of the entire campo rupestre community.
Archive | 2016
Tadeu J. Guerra; Daniel W. Carstensen; Leonor Patricia C. Morellato; Fernando A. O. Silveira; Fernanda Vieira da Costa
Mutualisms such as animal pollination and seed dispersal, and protection of plants and insects by ants are ubiquitous in terrestrial ecosystems. Currently, mutualistic interactions among plants and animals are recognized for their paramount importance in biodiversity maintenance, especially in tropical ecosystems. In this chapter, we review the literature and present unpublished data on the ecology of mutualistic interactions among free-living species in Brazilian megadiverse montane Rupestrian Grasslands, the Campo Rupestre. We focus on interactions between plants and their pollinators and seed dispersers, and also interactions between ants, myrmecophilous plants and trophobiont insects. We provide basic information on mutualistic interactions, including data on natural history in addition to more advanced studies using network-based approaches. Only in the past decade mutualistic interactions have become intensively studied in Campo Rupestre, but information is still scattered and concentrated for a few localities. Pollination is an important process for reproduction of most plant species studied so far, with bees and hummingbirds acting as the main pollinators. Seemingly, animal pollination is more important than seed dispersal for gene flow across plant populations. Most vertebrate seed dispersal is carried out by non-specialized avian frugivorous, but also by short-distance seed dispersers such as ants and lizards. Moreover, ants are diversified and abundant group that seem to play a major role in these ecosystems, acting as secondary seed dispersers, as nectar thieves, and as bodyguards of plants and insects. We conclude this chapter by pointing out some gaps in our knowledge and proposing avenues for future research.
Oecologia | 2017
Tadeu J. Guerra; Roberta L. C. Dayrell; André Jardim Arruda; Wesley Dáttilo; Alberto L. Teixido; João V. S. Messeder; Fernando A. O. Silveira
The extent of specialization/generalization continuum in fruit–frugivore interactions at the individual level remains poorly explored. Here, we investigated the interactions between the Neotropical treelet Miconia irwinii (Melastomataceae) and its avian seed dispersers in Brazilian campo rupestre. We built an individual-based network to derive plant degree of interaction specialization regarding disperser species. Then, we explored how intraspecific variation in interaction niche breadth relates to fruit availability on individual plants in varying densities of fruiting conspecific neighbors, and how these factors affect the quantity of viable seeds dispersed. We predicted broader interaction niche breadths for individuals with larger fruit crops in denser fruiting neighborhoods. The downscaled network included nine bird species and 15 plants, which varied nearly five-fold in their degree of interaction specialization. We found positive effects of crop size on visitation and fruit removal rates, but not on degree of interaction specialization. Conversely, we found that an increase in the density of conspecific fruiting neighbors both increased visitation rate and reduced plant degree of interaction specialization. We suggest that tracking fruit-rich patches by avian frugivore species is the main driver of density-dependent intraspecific variation in plants’ interaction niche breadth. Our study shed some light on the overlooked fitness consequences of intraspecific variation in interaction niches by showing that individuals along the specialization/generalization continuum may have their seed dispersed with similar effectiveness. Our study exemplifies how individual-based networks linking plants to frugivore species that differ in their seed dispersal effectiveness can advance our understanding of intraspecific variation in the outcomes of fruit–frugivore interactions.
PLOS ONE | 2018
Tadeu J. Guerra; João V. S. Messeder; André Jardim Arruda; Lisieux F. Fuzessy; Roberta L. C. Dayrell; Frederico de Siqueira Neves; Fernando A. O. Silveira
The balance between the costs and benefits of fleshy fruit production depends on the feeding behavior of their seed dispersers, which might effectively disperse seeds to farther areas or drop beneath parent plants some diaspores they handle during frugivory bouts. Nevertheless, the consequences of variation in fruit handling by primary seed dispersers on the secondary removal of diaspores remains poorly understood. We conducted a field study to determine how variation in fruit handling by avian frugivores affects short-term secondary removal of Miconia irwinii (Melastomataceae) diaspores by the ground-dwelling fauna in campo rupestre vegetation, southeastern Brazil. We conducted factorial experiments manipulating: (1) different outcomes of primary fruit/seed removal by birds, (2) distances of diaspore deposition from conspecifics, and (3) the access of ants and vertebrates to diaspores. We showed that secondary removal of diaspores was highly variable at the population scale, with an overall low removal rate by the ground-dwelling fauna (13% seeds, 19% fruits). However, we found that gut-passed seeds embedded in bird feces were less removed than seeds expelled from fruits. Gut-passed seeds were more likely to be removed by ant species acting as secondary dispersers, whereas pulp-free seeds dropped by birds were likely to interact with potential seed predators, including ants and rodents. We found no clear effect of dispersal from parent plant vicinity on seed removal, but fruit removal was significantly higher near parent plants. Partially defleshed fruits were more removed than intact fruits. The removal of fruits by ant and vertebrate rescuers, including lizards and birds, might reduce the costs of interactions with less effective dispersers that drop partially defleshed fruits under parent plants. Our study highlights that variation in fruit handling by primary avian seed dispersers mediate subsequent interactions among discarded diaspores and ground-dwelling animals, potentially affecting final seed fates. Moreover, we argue that escape-related benefits of dispersal can be contingent on how primary dispersers handle and discard seeds.
Plant and Soil | 2016
Fernando A. O. Silveira; Daniel Negreiros; Newton P. U. Barbosa; Elise Buisson; Flávio Fonseca do Carmo; Daniel W. Carstensen; Abel Augusto Conceição; Tatiana Cornelissen; Lívia Echternacht; G. Wilson Fernandes; Queila Souza Garcia; Tadeu J. Guerra; Claudia Maria Jacobi; José Pires de Lemos-Filho; Soizig Le Stradic; Leonor Patricia C. Morellato; Frederico de Siqueira Neves; Rafael S. Oliveira; Carlos Ernesto Gonçalves Reynaud Schaefer; Pedro L. Viana; Hans Lambers
Biodiversity and Conservation | 2017
Alberto L. Teixido; Peter E. Toorop; Udayangani Liu; Guilherme V. T. Ribeiro; Lisieux F. Fuzessy; Tadeu J. Guerra; Fernando A. O. Silveira
Revista Brasileira de Ornitologia - Brazilian Journal of Ornithology | 2013
Miguel Ângelo Marini; Tadeu J. Guerra
Sociobiology | 2013
Paula Cj Reis; Wesley D. DaRocha; Luiz Ad Falcão; Tadeu J. Guerra; Frederico de Siqueira Neves
Papéis Avulsos de Zoologia (São Paulo) | 2013
Marcelo Ferreira de Vasconcelos; Eduardo de Carvalho Dutra; Luiz Gabriel Mazzoni; Letícia Ferreira Pedroso; Alyne Perillo; Fernando Augusto Valério; Tadeu J. Guerra; Diego Petrocchi; Rodrigo Morais; Lucas Penna Soares Santos; Bruno Garzon; Juan Espanha Moreira Dias; José Enemir dos Santos; Allan Suhett de Morais; Letícia Souza Lima Guimarães; Frederico Innecco Garcia; Thiago Oliveira e Almeida; Carlos Eduardo Ribas Tameirão Benfica; Helberth José Cardoso Peixoto; Bruno Pardinho Ribeiro