Direct and indirect effects of roads on space use by jaguars in Brazil

Abstract

Roads pose an imminent threat to wildlife directly through mortality and changes in individual behavior, and also indirectly through modification of the amount and configuration of wildlife habitat. However, few studies have addressed how these mechanisms interact to determine species response to roads. We used structural equation modeling to assess direct and indirect effects (via landscape modification) of roads on space use by jaguars in Brazil, using radio-tracking data available from the literature. We fit path models that directly link jaguars’ space use to roads and to land cover, and indirectly link jaguars’ space use to roads through the same land cover categories. Our findings show that space use by jaguars was not directly affected by roads, but indirect effects occurred through reductions in natural areas on which jaguars depend, and through urban sprawl. Males´ space use, however, was not negatively influenced by urban areas. Since jaguars seem to ignore roads, mitigation should be directed to road fencing and promoting safe crossings. We argue that planners and managers need to much more seriously take into account the deforestation and the unbridled urban expansion from roads to ensure jaguar conservation in Brazil.

Human‐modified landscapes driving the global primate extinction crisis

“…Consequently, simultaneous autoregressive (SAR) models allowed us to examine the direct and indirect associations of anthropogenic and landscape attributes. The combination of both approaches is well‐established and commonly used to study ecological systems that are driven by interconnected processes in a single network (e.g., Cerqueira et al, 2021; Ilsøe et al, 2017; Kissling et al, 2008). Direct effects are estimated by the standardized regression coefficient between a predictor variable and a response variable (i.e., the direct link), whereas indirect effects correspond to paths originating at the HFP variable and passing through other variables before reaching primate species richness (Shipley, 2016).…”

“…In macroecological studies, different statistical analyses are employed in addition to SEMs, such as regression analysis, model selection, and multi‐model inference, among others. We applied a common method that has been previously used in different macroecological studies, for example, on woody plant and bird diversity (Kissling et al, 2008), mammal diversity (Gouveia et al, 2014), and jaguar ecology (Cerqueira et al, 2021). While various statistical analyses are available, there is no a priori best analysis, thus we focused on a singular method to avoid confusion, as opposed to using multiple analyses.…”

Towards causal relationships for modelling species distribution

“…However, due to technical limitations such as the application of SEM to data not fitting a Gaussian error distribution and the estimate of only linear relationships prevented a broader application of this methodology to data types commonly found in ecological studies (Grace, 2022; Lefcheck, 2016). Recent technical developments overcome some of these limitations (e.g., Carvalho‐Rocha et al., 2021; Cerqueira et al., 2021; Chu et al., 2019; Quiroga et al., 2021; Walentinowitz et al., 2023), but their application into SDMs remains surprisingly low.…”

“…Recent technical developments overcome some of these limitations (e.g., Carvalho-Rocha et al, 2021;Cerqueira et al, 2021;Chu et al, 2019;Quiroga et al, 2021;Walentinowitz et al, 2023), but their application into SDMs remains surprisingly low.…”

Effect of chronic traffic noise on behavior and physiology of plateau pikas (Ochotona curzoniae)

“…Road and traffic can affect terrestrial animal populations via fragmenting them into smaller sub-populations, which are more vulnerable to local extinction, increasing mortality directly or decreasing habitat amount and quality (Rytwinski and Fahrig, 2015). Around 194 million birds and 29 million mammals may be killed each year on European roads (Grilo et al, 2020); with the increase in traffic density, roadkills consisting of mammals and birds increased in Southern Spain (Canal et al, 2019); road reduced the natural area and space use of jaguars (Panthera onca) and wolf (Canis lupus), which prefer to cross low-speed and low-traffic-volume roads (Cerqueira et al, 2021;Dennehy et al, 2021); forest road can serve as barriers that impede movements and space use of red squirrel (Tamiasciurus hadsonicus grahamensis; Chen and Koprowski, 2016). Traffic also decreases animals' accessibility to food, mate, and resources, thus reducing the reproductive fitness and threatening population persistence (Fahrig and Rytwinski, 2009;Rytwinski and Fahrig, 2015;Secco et al, 2022).…”