Heterogeneity in jaguar habitat selection across a shrinking range amidst habitat loss and climate change

Author(s)

Alan Eduardo de Barros

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2025-02-06

Examining board members

Paulo Inácio de Knegt López de Prado; Adriano Garcia Chiarello; Francisco Voeroes Dénes; Vitor Vieira Vasconcelos

• Advisor: Paulo Inácio de Knegt López de Prado; Ronaldo Gonçalves Morato

Abstract

The jaguar (Panthera onca) occupies a wide variety of ecogeographic and bioclimatic regions, with subpopulations exposed to heterogeneous conditions in terms of resources, risks, and threat levels throughout its range. The species\' current distribution has already been reduced to half of its original extent, and habitat destruction has intensified due to cumulative impacts (e.g., deforestation, siltation, rising temperatures, drought, fire), even in regions considered less threatened. In this context, understanding how jaguars habitat use and selection vary, as well as the effects of disturbances gaining relevance, such as fire, becomes essential. Although jaguars are often associated with the presence of vegetation cover and water, their habitat preferences vary considerably, particularly concerning anthropogenic impacts. Despite this variability, most studies seek generalized patterns, focusing on average selection responses and often overlooking the factors driving heterogeneity. To address this gap, in the first chapter, we evaluated habitat selection variability by jaguars across their range. First, we applied integrated Step Selection Functions (iSSFs) and subsequently used a multilevel meta-analytic approach. Considering that each jaguar\'s habitat selection is influenced by the availability of resources and risks within its movement range (within home range), that this availability may be conditioned by proximity or regional factors (ecogeographic and bioclimatic), and that physical traits such as sex, age, and size can influence the motivation for movement and selection, we sought to understand how each of these factors contributes to explaining variation in selection for different environmental and anthropogenic variables. Our results revealed significant heterogeneity in habitat use and selection by jaguars, both among individuals and across their range. Individual and neighborhood effects explained up to 68% of the variability in selection coefficients. However, water selection and tolerance to human impacts were predominantly influenced by availability at the movement scale (increasing up to 47% in additional explanation). While we identified positive functional responses to vegetation cover availability, regional factors, especially bioclimatic zones, also played an important role in explaining variability in selection for these resources. Individual characteristics also accounted for part of the variability in responses to environmental and anthropogenic variables. These findings highlight the importance of considering spatial scales or hierarchies, such as orders of selection, and individual variability in habitat selection studies, particularly those covering large areas, such as a species distribution. Ignoring this variability may lead to misleading conclusions and compromise conservation strategies. In the second chapter, we explored the cumulative and emerging impacts on jaguar habitat and populations, focusing on the Pantanal as a case study. We investigated how the increasing incidence of wildfires, exacerbated by more severe droughts and higher temperatures, affected priority areas for jaguars and population estimates between 2004 and 2020 in the biome. During this period, the 2020 fires were the most severe, burning 31% of the Pantanal and affecting 45% of the estimated jaguar population (87% in Brazil). These fires impacted 79% of jaguar home ranges and 54% of protected areas overlapping with them. In addition to destroying essential habitats, the fires caused injuries to jaguars, impacting their survival due to displacement, hunger, dehydration, territorial defense, and reduced reproduction. These consequences also affect other species, compromising the regions ecological stability. We conclude by discussing that preventing future mega-fires requires addressing human-driven causes that exacerbate drought (such as deforestation, siltation, and carbon emissions), protecting water sources, expanding protected areas, regulating fire use, and preparing firefighting brigades before the dry season. Some of these measures have been implemented since then. The findings of this thesis reinforce the need to consider, quantify, and explore the causes of variability in jaguar habitat use and selection. Such variability should be used as a parameter to evaluate the generalizability of predictive spatial models, such as those proposing ecological corridors. Furthermore, by revealing the devastating impacts of wildfires in the Pantanal, we underscore the urgency of preventive and adaptive strategies to mitigate habitat and population loss. These results provide valuable insights for more effective conservation actions, tailored to the ecological particularities and emerging challenges across the species range. (AU)

• FAPESP's process: 18/24891-5 - How do jaguars move through the landscape? Integrated step selection and movement analyses applied to jaguar ecology and conservation
• Grantee: Alan Eduardo de Barros
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)