While at the Smithsonian Conservation Biology Institute I had the great pleasure of working with Beatriz Lopez, one of the many interns visiting the GIS lab from Brazil. I collaborated with Beatriz on the analysis of movement data from GPS collared capybaras (Hydrochoerus hydrochaeris) in natural and human-modified landscapes. That work eventually grew into a collaborative publication with lots of great scientists from Brazil and the USA and has just been published in the Journal of Mammalogy.
Capybara are the biggest rodent in the world and live in savannahs and forests always close to water. They are very social and are commonly found in groups of 20 or more. In this study we looked at the home range size and daily movement patterns of capybaras in natural landscapes and compared them to those in landscapes impacted by agriculture, roads and human settlements. The results show that home ranges were a striking 2.43 times greater in natural landscapes than in human-modified landscapes and indicate differences in ranging patterns between the two types of landscape. Capybaras tended to be more nocturnal and move shorter distances when in human-modified landscapes.
The aggregation of capybaras in very small home ranges might imply greater risk of diseases spread by tick infestations such as Brazilian spotted fever. In addition, capybara–vehicle collision may be increased during capybaras’ nocturnal activity. Not only do capybaras restrict their movements, they also show preference for forested areas where humans are usually not present. We also noted that shifts in movements may be the result of differences in resource availability, with more food and water available in modified landscapes the capybara don't have to move as far.
It is possible that they have shifted their movement patterns to become more nocturnal to avoid human activity and don't have to contend with their main nocturnal predator, the jaguar, which in the natural landscapes would make moving around at night a very risky proposition.
There have been a lot of studies recently on the impact of human activity on the movement behaviour of animals. Some show increased home ranges as animals are forced forage over a greater area while trying to avoid humans whereas others, like the capybaras, show reduced movements as they can take advantage of abundant resources. This does however increase the likelihood of human-capybara conflict through crop-raiding and vehicle collisions. We recommend that transportation agencies invest in mitigation measures to reduce access by capybaras to roads and railways, such as constructing suitable fences in combination with underpasses and culverts, in addition to animal crossing signs and speed management at specific times and locations. Ultimately, we suggest for transportation systems, whenever possible, to avoid the construction of transportation infrastructure in capybaras’ home range areas. This work highlights the importance of developing a full picture of the movement behaviour of species to understand how they may be impacted by landscape modifications.
Check out the full paper here.
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