Name: Gabriela Colombo de Mendonça
Type: MSc dissertation
Publication date: 31/05/2021
Advisor:

Name	Role
Ana Carolina Loss Rodrigues	Co-advisor *
Yuri Luiz Reis Leite	Advisor *

Examining board:

Name	Role
Ana Carolina Loss Rodrigues	Co advisor *
Joyce Rodrigues do Prado	External Alternate *
Marinez Ferreira de Siqueira	External Examiner *
Rita Gomes Rocha	Internal Examiner *
Roberta Paresque	Internal Alternate *
Yuri Luiz Reis Leite	Advisor *

Summary: ABSTRACTChanges in the Earth’s climatic conditions can affect geographic distributions of species, causing variations in patterns of diversity and occurrence across space and time. Justas in response to past climate fluctuations, species will tend to respond to projected future climate changesas well. Due to their high specialization, low adaptability and low mobility, mountain species may be more affected by climate change than species that occur at mid-and low altitudes. To better understand these effects, we characterized the climatic niches of Juliomys ossitenuisand Juliomys pictipes(Rodentia: Cricetidae), two arboreal rodents endemic to the Atlantic Forest that differ in altitudinal rangebutoccur in sympatry in some localities. Currently, Juliomys ossitenuisis restricted toregions above 800 m, while Juliomys pictipes is distributed along the altitudinal gradient from sea level to 2,000 m of altitude, leading to thecoexistence of these species at medium altitudes. Usingclimate modeling, we investigatedthe potential effects of climate fluctuations on the environmental suitability of both species from the Last Glacial Maximum at 21,000 years ago to the year 2070 underdifferent global warming scenarios. Our research has shown that J. pictipes and J. ossitenuis share a climate niche but have different occupation densities and climatic range, suggestingthatin addition to spatial niche segregation, they mayrespond in different ways to climate change. Juliomys pictipesshowed less reduction of adequate area byincreased temperature and reduced precipitation than Juliomys ossitenuis, which showedmore significant events of adequate area reduction and altitudinal movement. We conclude that J. ossitenuisand J. pictipes have similar climatic niches, but are spatially segregated at different levels, which is probably associated with their ecological characteristics. We also conclude that J. ossitenuis,which is the species restricted to the highest altitudes,is more susceptible to the predicted changes in the climate. Keywords: Juliomys; altitude; sympatry; climate suitability; Atlantic Forest.

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