The Miners of South America: an ecological approach to the genus Geositta

• Autor(a) principal: Ricardo Camargos de Meireles
• Data de Publicação: 2022
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Repositório Institucional da UFMG
• Texto Completo: http://hdl.handle.net/1843/53498
• topic: Andes; Brazil; neotropical birds; Geositta; ecological niche modeling; nest survival; Ecologia; Ecossistema andino; Aves; Nicho

The genus Geositta is a group of terrestrial birds belonging to the family Scleruridae and distributed throughout South America. Composed of eleven species, they inhabit open and arid environments, such as grasslands, shrubby, rocky and desert areas, in addition to sharing similar behaviors, such as a mostly insectivorous diet and being excavators. Of the eleven species belonging to the genus, Geositta poeciloptera is currently the most studied and also the only one threatened with extinction. Considering all the knowledge about the species, in this study we intend to answer the questions that occasionally arose over seven years of fieldwork. Our main questions were: (1) What are the effects of precipitation and nest architecture on G. poeciloptera nest survival? (2) How will climate change affect the future distribution of G. poeciloptera in the face of different greenhouse gas emission policies? (3) As they share similar habitat preferences, what will be the effect of climate change and altitude on the distribution of the seven non-migrating species distributed in the tropics? Based on 86 monitored nests and architectural measurements taken in the Upper Rio Grande Grasslands region, we calculated apparent success and modeled daily nest survival rates (DSR). Apparent overall nest success was 58% and estimates based on DSRs were ~45%. Nest phase, cavity entrance area, nest height and linear temporal trend were the main factors that influenced DSRs. For questions 2 and 3 we used occurrence records from different sources in addition to those collected in the fieldwork and resorted to ecological niche modeling using different algorithms. For future predictions, we use two General Circulation Models and different greenhouse gas emission policy scenarios. For G. poeciloptera, we found a not very optimistic future, with a considerable decrease in areas climatically suitable for the species. As for the non-migrating species, we found different patterns of climatically suitable areas for lowland species and highland species, which seems to be due to the vegetational and elevational zonation of the Andean slopes, which provide greater humidity in these areas of intermediate elevation. Our results allow us to better understand the ecology of this few studied bird family, in addition to contributing to the conservation strategies of these species.