André Jardim Arruda

Intraspecific variation in fruit–frugivore interactions: effects of fruiting neighborhood and consequences for seed dispersal

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.

Flora of the cangas of Serra dos Carajás, Pará, Brazil: Isoetaceae

This study presents taxonomic treatment of the species of Isoetaceae from Serra dos Carajás, Pará, Brazil. Two species occur in this locality (Isoetes cangae and I. serracarajensis). We provide descriptions, illustrations, images of the megaand microspores, comments, distribution data and a key for these species as a contribution to the knowledge of the flora of the cangas from this area.

Differential gender selection on flower size in two Neotropical savanna congeneric species

Larger flowers greatly increase among-individual pollen exchange within populations. However, water costs associated to transpirational cooling also increase with increasing flower size. Overall, the interplay between pollen and resource limitation determines the intensity of selection on flower size and this process is mostly dependent on gender and ecological context. To examine how pollinators and water use affect flower size, we determined corolla transpiration, pollen limitation, and selection through male and female fitness in two Kielmeyera species from the Brazilian cerrado flowering at different seasons. Hand-pollination experiments suggested pollen limitation through female fitness in both species, but K. coriacea showed lower limitation levels than K. regalis. For male fitness, the percentage of pollen removal was 1.5-times higher in K. coriacea. Higher air temperature and water deficit during flowering season of K. coriacea resulted in 4-fold higher corolla transpiration rates compared to K. regalis. Selection on flower size through male function was positive and significantly higher than selection through female components in both species. We also detected stabilizing selection in K. coriacea and positive selection in K. regalis on flower size through seed number. Our results suggest that selection on flower size in K. coriacea was mainly limited by water, whereas in K. regalis it was more limited by pollen. We demonstrate that differences in pollen and abiotic resource limitation determine gender-specific selection on flower size.

Flora das cangas da Serra dos Carajás, Pará, Brasil: Aspleniaceae

This study adressed the Aspleniaceae taxa recorded in ferruginous formations of Serra dos Carajas, Para state, bringing descriptions, illustrations, geographical distribution, and comments. In the study area one genus and four species were recorded: Asplenium formosum, Asplenium salicifolium, Asplenium serratum, and Asplenium stuebelianum.

Flora das cangas da Serra dos Carajás, Pará, Brasil: Thelypteridaceae

This study addressed the Thelypteridaceae taxa recorded in ferruginous formations of the Serra dos Carajas, Para state, with descriptions, illustrations, geographical distribution, and comments. In the study area four genera and seven species were recorded: Christella hispidula, Cyclosorus interruptus, Goniopteris abrupta, G. pennata, G. tetragona, G. tristis and Meniscium maxonianum.

Flora das cangas da Serra dos Carajás, Pará, Brasil: Oleandraceae

This study addressed the Oleandraceae taxa recorded in ferruginous formations of Serra dos Carajas, Para state, with descriptions, illustrations, geographical distribution, and comments. In the study area only one species was recorded: Oleandra pilosa.

Flora das cangas da Serra dos Carajás, Pará, Brasil: Lycopodiaceae

This study addressed the Lycopodiaceae taxa recorded in ferruginous formations of the Serra dos Carajas, Para state, with descriptions, illustrations, geographical distribution, and comments. In the study area only one species was recorded: Palhinhaea cernua.

Flora das cangas da Serra dos Carajás, Pará, Brasil: Dennstaedtiaceae

This study addressed the Dennstaedtiaceae taxa recorded in ferruginous formations of Serra dos Carajas, Para state, with descriptions, illustrations, geographical distribution, and comments. In the study area only one species was recorded: Pteridium arachnoideum.

Flora das cangas da Serra dos Carajás, Pará, Brasil: Cyatheaceae

Este estudo trata os taxons de Cyatheaceae encontrados nas formacoes ferriferas da Serra dos Carajas, estado do Para, com descricoes, ilustracoes, distribuicao geografica e comentarios. Na area estudada foi registrada apenas Cyathea pungens.

Flora das cangas da Serra dos Carajás, Pará, Brasil: Lygodiaceae

Este estudo trata dos taxons de Lygodiaceae encontrados nas formacoes ferriferas da Serra dos Carajas, estado do Para, com descricoes, ilustracoes, distribuicao geografica e comentarios. Na area estudada foi registrada apenas Lygodium venustum.