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Made available in DSpace on 2020-12-12T02:34:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Anthropogenic activities are the main cause of habitat loss and fragmentation, which directly affects biodiversity. Disruption in landscape connectivity among populations may affect complex interactions between species and ecosystem functions, such as pollination and seed dispersal, and ultimately result in secondary extinctions. Urbanization, one of the most intense forms of landscapes changes, has been reported to negatively affect bird and plant diversity. Still, little is known about the effects of urban landscapes on interaction networks. We investigated the relationship between urban landscape structure and plant-frugivore networks at different spatial scales. Coupling interaction data from urban areas and a model selection approach, we evaluated which landscape factors best explained the variation in urban networks properties. Our results indicate that urbanization decreases bird richness, mainly through the loss of habitat specialist species, which results in networks being composed mainly of birds well adapted to urban dwelling. We found that interaction evenness, a measure of homogeneity of interaction distribution between species, increases with urbanization. This is due to the strong dominance that generalist birds had in network composition because they foraged on all available fruits, including exotic plants. The ensuing homogenization of interactions can reduce the resilience of networks and affect the efficiency of ecosystems functions. Thus, urbanization plans should consider the proportion and distribution of green areas within cities, coupling human and ecosystem wellbeing. Programa de Pós-Graduação em Ecologia e Conservação Universidade Federal do Paraná. Centro Politécnico Jardim das Américas Laboratório de Interações & Biologia Reprodutiva Universidade Federal do Paraná. Centro Politécnico Jardim das Américas Departamento de Biologia Faculdade de filosofia ciências e letras de Ribeirão Preto Universidade de São Paulo FFCLRP-USP Ribeirão Preto Universidad de Buenos Aires Facultad de Agronomía Cátedra de Botánica General Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) Laboratório de Ecologia Vegetal Universidade Federal do Paraná. Centro Politécnico Jardim das Américas Programa de Pós-Graduação em Ciências Florestais Universidade Federal do Paraná. Jardim Botânico Laboratório de Ecologia Espacial e Conservação (LEEC) Departamento de Ecologia. Universidade Estadual Paulista UNESP Laboratório de Ecologia Espacial e Conservação (LEEC) Departamento de Ecologia. Universidade Estadual Paulista UNESP CNPq: 309453/2013-5 CNPq: 313801/2017-7 CNPq: 445405/2014-7

One of the major challenges in ecology is to understand the relative importance of neutral- and niche-based processes structuring species interactions within communities. The concept of neutral-based processes posits that network structure is a result of interactions between species based on their abundance. On the other hand, niche-based processes presume that network structure is shaped by constraints to interactions. Here, we evaluated the relative importance of neutral-based process, represented by species' abundance (A) and fruit production (F) models, and niche-based process, represented by spatial overlap (S), temporal overlap (T) and morphological barrier (M) models, in shaping the structure of a bird-seed dispersal network from the Brazilian Atlantic Forest. We evaluated the ability of each model, singly or in combination, to predict the general structure [represented by connectance, nestedness (NODF), weight nestedness (WNODF), interaction evenness and complementary specialization] and microstructure of the network (i.e., the frequency of pairwise interactions). Only nestedness (both NODF and WNODF) was predicted by at least one model. NODF and WNODF were predicted by a neutral-based process (A), by a combination of niche-based processes (ST and STM) and by both neutral- and niche-based processes (AM). NODF was also predicted by F and FM model. Regarding microstructure, temporal overlap (T) was the most parsimonious model able to predict it. Our findings reveal that a combination of neutral- and niche-based processes is a good predictor of the general structure (NODF and WNODF) of the bird-seed dispersal network and a niche-based process is the best predictor of the network's microstructure.

Climate change is significantly influencing phenology. One potential effect is that historically interacting partners will respond to climate change at different rates, creating the potential for a phenological mismatch among previously synchronized interacting species, or even sexes of the same species. Focusing on plant demographics in a plant–pollinator interaction, we develop a hybrid dynamical model that uses a “non-autonomous” differential equation system (Zonneveld model) for within-season dynamics and discrete equations for season-to-season dynamics. Our model outlines how and when changes in the relative phenologies of an interacting species pair will alter the demographic outcome of the interaction. For our plant–pollinator system, we find that plant population growth rates are particularly sensitive to phenology mismatch when flowers are short-lived, when pollinators are short-lived, or when flowers and pollinators exhibit high levels of within-population synchrony in emergence or arrival dates. More generally, our aim is to introduce the use of hybrid dynamical models as a framework through which researchers can directly explore the demographic consequences of climatically driven phenological change.

Unfortunately, the detailed description of the ESM material went wrong in the published version of the dataset.