The effect of roads on spider monkeys’ home range and mobility in a heterogeneous regenerating forest

Abstract

Arboreal fauna living in tropical ecosystems may be particularly affected by roads given their dependency on forest cover and the high vulnerability of such ecosystems to changes. Over a period of 4 yr, we followed subgroups of spider monkeys living in a regenerating dry tropical forest with 8.2 km of roads within their home range. We aimed to understand whether roads shaped the home range of spider monkeys and which road features affected their movement. Only 18 percent (3 km) of the spider monkeys’ home range perimeter bordered with roads; these roads had greater habitat disparity between road sides than roads inside the home range. Although monkeys were reluctant to be close to roads, and roadside habitat contained low proportions of mature forest, spider monkeys crossed roads at 69 locations (7.5 crossings per kilometer). The main road characteristic affecting crossings was canopy opening size, with greater probability of crossing where canopy openings were smaller. Our findings support the importance of canopy opening size for road crossing of arboreal taxa, but they also indicate the relevant role roadside forest structure may have. Minimizing canopy opening size and forest disturbance along roads can facilitate the movement of arboreal fauna and preserve the important role of spider monkeys and other arboreal taxa in seed dispersal and thus the maintenance and regeneration of forest diversity.

Seeds and the City: The Interdependence of Zoochory and Ecosystem Dynamics in Urban Environments

“…For example, roads surrounding a forest patch were found to act as a movement barrier for scatter hoarders, effectively constraining seed movements to the fragment (Niu et al, 2018). This concurs with findings from non-urban (Asensio et al, 2017) and urban a Type of zoochory: E, endozoochory; M, myrmecochory; S, synzoochory. b City size: S, small urban area (population = 50,000-200,000); M, medium urban area (population = 200,000-500,000); L, metropolitan area (population = 0.5-1.5 million); XL, large metropolitan area (population ≥1.5 million) (OECD, 2018).…”

The impact of roads on the movement of arboreal fauna in protected areas: the case of lar and pileated gibbons in Khao Yai National Park, Thailand

“…Similarly, in a different study, birds flew away from roads if vegetation was lower on the opposite side of the road than the side where the bird was sitting (Husby & Husby 2014). Spider monkeys also did not pass over roads at locations with high habitat disparity between roadsides (Asensio et al 2017). Thus, gibbons may tolerate relatively well the presence of roads in their territories if the damage made to the roadside vegetation of particular bridging locations is minimum.…”

“…This highway constitutes a 'deadly barricade' to animals that attempt traversing it with an estimate of 9684 vertebrate kills by vehicle collision per year (Silva et al 2020). This linear infrastructure virtually isolates the population of the pileated gibbon into Khao Yai Park by discontinuing dispersal from its main geographical distribution to the east (Asensio et al 2017).…”

“…That is, there is a greater road permeability to arboreal individuals where the distances necessary to cross roads using tree branches are shorter. Accordingly, roads can also outline the edges of home ranges in arboreal taxa at those road segments with large gaps across both sides (Asensio et al 2017).…”

“…Gibbons of the genus Hylobates are small apes that live in small family groups consisting of an adult mating pair and offspring (Bartlett 2009;Brockelman 2009;Leighton 1987;Reichard 2003). Gibbons live in relatively small and highly stable territories across years (ca 25-40 ha), which they quickly traverse on a daily basis (Asensio et al 2017;Bartlett 2009;Bartlett et al 2015;Cheyne et al 2019). Gibbons constitute suitable models to investigate how roads affect the movement of arboreal animals given its strict tree lifestyle and dependence on areas of quality forest (Carpenter 1972;Meijaard et al, 2005;Oka et al 2000;Syxaiyakhamthor et al 2019).…”