Scrambling in the dark: Study shows animals forced to be more active from dusk to dawn to escape human disturbance

Most species studied exhibited reduced activity in conservancies during daytime, with increased activity at dusk, night, dawn
Photo: iStock
Photo: iStock

Human activities have forced wildlife to adapt to a new temporal pattern, a study conducted by the University of Minnesota College of Biological Sciences showed. Animals have become more active primarily between dusk and dawn, the scientists observed.

This shift in behaviour was a response to human disturbance, with animals avoiding times when humans are most active, as reported in multiple studies.

Even within protected areas, tropical mammals are not saved from the impact of human activities occurring beyond their boundaries. To gain a deeper understanding of this phenomenon, researchers conducted a case study focusing on the conflict between humans and wildlife in East Africa.

In pastoralist areas of the region’s vast savannas, wildlife is increasingly being pushed to share its habitat with livestock. Landowners in these regions often turn to eco-tourism to supplement their incomes, fostering coexistence between livestock and wildlife while promoting sustainable conservation of the ecosystem.

To assess how the presence of cattle affects species activity, researchers selected sampling sites within the Greater Serengeti-Mara ecosystem (GSME) spread over Tanzania and Kenya. Specifically, they chose two sites: Serengeti National Park in Tanzania and Maasai Mara Reserve in Kenya, which are home to large mammals such as spotted hyenas, lions, leopards and cheetahs.

The researchers used remote cameras to closely observe the movement patterns of wildlife in pastoralist areas, aiming to evaluate the impacts of both human and cattle pressures on sympatric wildlife species. Their comparative assessment, published in the Journal of Animal Ecology, focused on the activity patterns of 16 herbivore species, aiming to characterise the potential impacts of pastoralism on wildlife within a multi-use landscape.

The study’s findings indicated that most species exhibit reduced activity in the conservancies during daytime, with increased activity levels at dusk, night and dawn. 

Some species, including eland, zebra, wildebeest and Grant's gazelle, only displayed heightened activity at dawn and dusk. Conversely, buffalo, impala, Thomson's gazelle and warthog exhibited increased activity exclusively at night, while bushbuck and hippos were found to be more active during the day.

The cover of darkness offers a temporary refuge for wildlife. As humans withdraw indoors, leading to a decrease in noise and activity levels, animals venture out from their hiding to hunt.

The enhanced activity at dawn may be driven by temperature differences between dawn and dusk, with species favouring the cooler morning hours to escape heat stress. Additionally, the brief midday peaks observed in several Serengeti species may reflect their strategy of seeking shade to escape the scorching midday heat.

The study underscores how sharing habitat with livestock can significantly modify the daily behaviour of wild herbivores. These discoveries carry significant implications for the management of human-wildlife conflicts in pastoral regions, particularly in East Africa, where both ecotourism and livestock play pivotal roles in the local economy. 

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