Nest predators use visual, acoustic and chemical cues to locate nests. In the Neotropics, predation is high being the main cause of nest failure. Despite that, it is still not completely clear what kind of information predators are using to find nests or whether predators respond differently according to habitat characteristics. Here, we executed an experimental manipulation to investigate how different ecological factors influence nest predation probability. We hypothesised that egg conspicuousness, nest clustering and a more open vegetation structure would increase nest predation probability, and that nest predation would be higher during the breeding season of most avian species in the region. We used artificial nests baited with plasticine and quail eggs (Coturnix coturnix), manipulated egg coloration and nest density. Artificial nests were distributed over forest and savanna-like vegetations. Overall predation rate was 40.9%. We found that nests baited with conspicuous eggs, located in open habitats, at higher densities and during the dry period were more predated. Results suggest that main predators must be visually orientated, and that egg crypsis is an important trait for open-nest species in the area. Moreover, a higher nest density may affect predator behaviour, favouring an increase in nest searching, which may be facilitated in open habitats.

We investigated whether changes in nutrient availability affected N, P, S and polyphenol concentrations in different leaf-development stages of three brevideciduous and three evergreen dominant woody species in a nutrient-limited savanna woodland in Central Brazil. Treatments included eight years of annual fertilization with 100 kg ha−1 of N, P, N plus P and control, each replicated in four randomized 15 × 15-m plots. All species increased S concentrations (minimum 28%) in young and mature leaves in fertilized plots. Dalbergia miscolobium decreased total phenol concentrations with P (−34.3%, −23.7%) and NP fertilization (−28.2%, −17.1%). Blepharocalyx salicifolius increased total phenol (27.6%, 18.8%) and tannin (46.3%; 43.5%) in P fertilized and increased total phenol (33.9%) and tannin (27.8%, 43.5%) in NP fertilized plots. Total phenol concentration decreased with leaf age in Ouratea hexasperma, Styrax ferrugineus and Blepharocalyx salicifolius, which also decreased tannin concentration with leaf age. For all treatments, brevideciduous species had higher N, P, total phenols and tannin concentrations and lower S concentration than evergreens. These differences between phenological groups suggest that tropical ecosystems responses to environmental changes are more complex than anticipated by global vegetation models, with consequences for predictions in ecosystem functions and resilience.

Miconia chartacea is a widely distributed tree in Brazil, occurring at altitudes ranging from 300 m to 1900 m in the Caatinga, Cerrado and Atlantic Forest biomes. In this work we attempted to classify M. chartacea seeds regarding their behaviour during storage and their germination syndrome and to determine, from a storage test in Cerrado soil and laboratory conditions in situ and ex situ, the longevity of seeds, as well as the capacity of the species to form a soil seed bank. The results suggested that M. chartacea seeds form a transient soil seed bank in the Cerrado and can be classified as orthodox in terms of storage behaviour, although the seeds are dispersed with a relatively high water content. The life span of seeds was favoured in soil-stored seeds in comparison with dry storage at 25°C, whereas storage at low temperatures prevented a decrease of the seed's germinability with storage time (330 d). M. chartacea seeds are dispersed during the dry season and germinate during the next rainy season, which can be classified as an intermediate–dry germination syndrome. Seeds of this species are dispersed in the Cerrado when temperatures and soil moisture are relatively low, which favours the formation of a soil seed bank, considering that the seeds tolerate desiccation and their longevity is favoured by low temperatures. A transient seed bank type is favoured by the loss of viability in storage at warm temperatures linked to the rainy season, and the predictable seasonal variations in climate in the region, with germination being restricted to the beginning of the rainy season.