Just as humans may leave home five minutes early to avoid a talkative neighbor or leave late to avoid a rude co-worker, carnivorous mammals may go out of their way to avoid other species. But they’re not trying to navigate difficult social interactions; rather, they negotiate space and resources to survive.
The researchers monitored this temporal niche partitioning intermittently for six years with 73 infrared-triggered sensor cameras installed at three sites in the Malaysian state of Sabah in Borneo, the world’s third-largest island. The international collaboration published its findings, and what they could mean for the mechanism of coexistence between competing mammals, on October 6 in Scientific reports.
“About 20% of mammalian species globally are at risk of extinction, primarily due to threats such as habitat loss and overexploitation,” said first author Miyabi Nakabayashi, assistant professor at the Graduate School of Advanced. Science and Engineering from Hiroshima University. “The status of mammals in the Indomalayan Kingdom – one of Earth’s eight biogeographic regions, covering most of South and Southeast Asia – is among the worst in the world.”
According to Nakabayashi, one of the main obstacles to effective and realistic solutions to reduce the rate of endangered species is the scarcity of basic ecological information on mammals in the Indo-Malaysian region.
“Information regarding temporal activity patterns of animals is crucial for assessing responses to anthropogenic disturbances and for enabling the implementation of appropriate conservation measures,” Nakabayashi said. “Camera trapping is one of the most useful techniques for studying cryptic and rare animals.”
The researchers collected 37,379 photos over a total of about three active years. Although the first cameras were installed in 2010 and the last were removed in 2016, there have been significant periods of bad weather or logistical problems – such as insect nesting – which rendered the cameras unusable for long periods.
In the dataset, the researchers identified nine distinct carnivore species with sample sizes greater than 10 and categorized their activity patterns by time of day. Of the species, six were active at night, two were active during the day, and one was active regardless of time.
Some of the closest animals demonstrated clear temporal segregation, including two feral cats, one of which was nocturnal while the other preferred daytime. However, the researchers also found that three species of civets were all active at night, which could be due to limited competition for resources because all three species eat a variety of food items, Nakabayashi said.
The researchers also found that tourism can impact mammal behaviors. Tourism activities – primarily non-lethal ecotourism events – were conducted at all study sites during the study period. However, only one site hosted nocturnal tourist activities. Common palm civets at the other two sites had two clear peaks in temporal activity at night, but the same species at the site with nocturnal tourism had unclear and delayed temporal movement.
“Potential benefits of ecotourism can include reduced threats to wildlife,” Nakabayashi said, noting that community-based ecotourism can bring important benefits such as alternative incomes that inspire local communities and policy makers to protect species in areas of interest. “But our results indicate that a species’ temporal activity pattern could be directly affected by tourism activity. The effect of tourism on animal behavior needs to be assessed, even if it is ecotourism. non-lethal.”
The researchers also recommended a two- to three-year study with at least 10 cameras to collect more data on carnivore activities.
“Current information is too limited and sporadic to understand basic mammal behaviors, which may affect progress in assessing and improving threatened status,” Nakabayashi said. “We should accumulate more information about rare species to determine their basic ecology and reassess whether current conservation management strategies are appropriate.”
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Material provided by Hiroshima University. Note: Content may be edited for style and length.