Dynamics and coexistence in a system with intraguild mutualism

It is a tenet of ecological theory that two competing consumers cannot stably coexist on a single limiting resource in a homogeneous environment. Many mechanisms and processes have since been evoked and studied, empirically and theoretically, to explain species coexistence and the observed biological diversity. Facilitative interactions clearly have the potential to enhance coexistence. Yet, even though mutual facilitation between species of the same guild is widely documented empirically, the subject has received very little theoretical attention. Here, we study one form of intraguild mutualism in the simplest possibly community module of one resource and two consumers. We incorporate mutualism as enhanced consumption in the presence of the other consumers. We find that intraguild mutualism can (a) significantly enhance coexistence of consumers, (b) induce cyclic dynamics, and (c) give rise to a bi-stability (a 'joint' Allee effect) and potentially catastrophic collapse of both consumer species. © 2012 Elsevier B.V.

Spatial and temporal distribution of tadpole assemblages (Amphibia, Anura) in a seasonal dry tropical forest of southeastern Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Diversidade e distribuição espaço-temporal de anuros em região com pronunciada estação seca no sudeste do Brasil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

An austral anuran assemblage in the Neotropics: seasonal occurrence correlated with photoperiod

The study describes habitat use and temporal occurrence of calling males for an austral anuran assemblage in the Neotropics, southern Brazil. Three study sites (S1 - a permanent river and a stream, S2 - a dam and backwater, S3 - two permanent ponds periodically connected) were sampled between August 2005 and July 2006. The site S3 presented the richest and most diverse assemblage and habitat use within studied sites, and was partitioned by species groups. Richness and abundance of calling males for overall assemblage were seasonal, concentrated in spring and summer and correlated with photoperiod. Temperature, rainfall and air humidity were not correlated with the richness and abundance of calling males. Photoperiod also explained the calling seasons when species were analyzed individually. Habitat use and temporal occurrence were complementary in the partitioning of breeding resources, explaining species coexistence.

Mudanças ontogenéticas na dieta de Oreochromis niloticus and Tilapia rendalli da represa de Barra Bonita (rio Tietê, Estado de São Paulo, Brasil)

The Nile Tilapia, Oreochromis niloticus, and the Congo Tilapia, Tilapia rendalli, are important members of the African cichlids, and have been introduced to many Brazilian lakes and reservoirs. These species exhibit a large feeding flexibility and may modify their habits during their growth. In the Barra Bonita reservoir, these species are well adapted, representing more than 80% of fish. This study aimed to analyze ontogenetic variation with regard to the diet of these species in this important reservoir. Samples were taken monthly, from March 2007 to February 2008, in Anhembi, São Paulo State. Both species were analyzed by grouping individuals according to size classes. The coexistence of these species was observed in this environment, to which fish were introduced, as well as discreet differences in diet, being that Oreochromis niloticus was considered as an detritivorous, since the detritus was constant in the diet of almost all size classes, and presents some changes in its diet according to the different size classes. While T. rendalli may was defined as herbivorous, and the contribution of food resources to the diet of T. rendalli seems to be different from that of O. niloticus along the size classes.

Processos ecológicos e filogenéticos na estruturação de comunidades de girinos

Pós-graduação em Biologia Animal - IBILCE

Ecologia trófica de pequenos mamíferos não voadores em uma área contínua de Mata Atlântica

Pós-graduação em Ciências Biológicas (Zoologia) - IBRC

Relação entre tamanho corporal e estrutura de comunidade em anfíbios anuros do município de Botucatu/SP

Pós-graduação em Ciências Biológicas (Zoologia) - IBB

Relação entre os atributos funcionais e características do habitat em comunidades de girinos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Spatio-temporal distribution of calling male frogs in Morro do Diabo State Park (Southeastern Brazil): implications for conservation and management in a seasonally dry tropical forest

The aims of this study are to determine how anuran calling males are spatially and temporally distributed in the Morro do Diabo State Park (MDSP), and to test for indicator species in different breeding habitats. We found high species turnover among breeding habitats of different hydroperiods. Our results indicate that spatial partitioning is more important than seasonal occurrence in permitting species coexistence at MDSP. Indicator Species Analysis identified one species associated with a local stream, one species associated with permanent ponds, two species associated with temporary ponds, and three species associated with a semipermanent pond. Guilds of species do not appear to stratify their distributions throughout the year, since most species occur during the rainy and warm months and are thus temporally overlapping. The main conservation implication of our work is the need to protect the different areas of the park where these unique breeding habitats, and their associated anuran assemblages, are found.

Temporal variation in the abundance of two species of thrushes in relation to fruiting phenology in the Atlantic rainforest

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Resource use and coexistence of two syntopic hylid frogs (Anura, Hylidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Two species of swimming crabs of the genus Achelous (Crustacea, Brachyura): environmental requirements determining the niche

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)