"Unraveling the Reproductive Biology of Neotropical Birds Along Altitudinal Gradients".
Altitude, life history, reproductive effort, clutch size, egg volume, climate, nest type, phylogeny
The reproductive strategies of birds are related to the environment in which they live. Elevation gradients can provide important information about life history, as abiotic factors (temperature, precipitation and atmospheric pressure) and biotic factors (predation) change with elevation gradients and influence the reproductive biology of birds. There is a gradual reduction as altitude increases, but rainfall can vary considerably across these gradients, which can influence the productivity of the environment and the availability of food resources. In addition, changes in climate can alter the life history of species that live on plains and at high elevations, reorganizing, restricting or extinguishing species. Some reproductive parameters such as clutch and egg size are still not well understood across altitudinal gradients in the Neotropical region. In the following chapters I aimed to analyze the reproductive patterns of clutch size and egg volume in elevation gradients. The first chapter focuses on clutch size. The hypothesis tested is that clutch size is smaller at higher elevations. The second chapter analyzes the variation in egg volume in relation to environmental factors (temperature, temperature isothermality and precipitation) and ecological factors (nest type) across elevation gradients. The main hypotheses are that at lower temperatures (higher elevations) and higher rainfall, the larger the egg size will be. The type of nest should also have an influence, since closed nests allow the eggs to be less exposed to the external environment, favoring an ideal microclimate and preserving egg volume, while open nests are expected to increase egg volume. The third chapter looks at the influence of the future climate (2100) on clutch size and egg volume. The main hypothesis is that temperature will increase and play a leading role in changing the life history of the species. As a result, clutch size and egg size should decrease. Neotropical elevation gradients still need to be further explored. Due to the few largescale investigations on the subject in tropical systems, a clearer understanding of the reproductive investment of Passeriformes in altitudinal gradients is needed.