Washington [US]May 23 (ANI): A team of researchers led by scientists from the University of California – Santa Cruz analyzed data from 3,212 camera traps to show how human disruption could change the make-up of mammal communities in North America.
The study, published in Global Change Biology, builds on the work of a previous team that investigated how animals in the Santa Cruz Mountains respond to human disruption. For example, local observations have shown that species such as cougars and bobcats are unlikely to be active in areas where humans are present, while deer and wood lice become more daring and lively. But it is difficult to generalize such findings across larger geographies, because interactions between humans and nature are often unique at the regional level.
To identify which mammal species might be better equipped to coexist with humans, the team combined data from their camera traps with data from researchers in the United States, Canada and Mexico. This allowed them to track 24 species across 61 regionally diverse camera trap projects to get even bigger trends showing.
“We have been very interested in how human disturbances affect nature for a long time, and we thought it would be interesting to see how animals generally respond to similar human pressures in North America,” said Chris Wilmers, an environmental expert. Professor of Studies and Director of the Santa Cruz Puma Project, who is the lead author of the paper, along with lead author Justin Suraci.
The team was particularly interested in understanding how mammals respond to different types of human conditions and whether these responses are related to species characteristics, such as body size, diet, and the number of young. Overall, the paper found that 33 percent of mammalian species responded negatively to humans, meaning that they were less likely to appear in highly disturbed places and were less active when present, while 58 percent of the species were positively related to the condition.
To get a closer look at these trends, the team split their findings into two different types of human disturbance. One of these factors was the impact on human development: the things that people build, such as roads, homes, and farmland. The other is the mere presence of humans, including activities such as entertainment and hunting, because fear of humans can change an animal’s behavior and its use of space.
When comparing continental data from camera trap sites with varying levels of human evolution, the researchers found that bears, lynx, wolves and wolverines are generally less likely in more developed areas and less active when they visit. Elk and martins were also less active in regions with a higher developmental footprint.
Meanwhile, raccoons and white-tailed deer were previously stuck in more developed areas and were more active in these spaces. Elk, deer, striped skunks, red foxes, cats, wolves, and cougars are unlikely to be found in the evolving landscapes, but they were most active in these areas.
Some species that repeat in more developed regions may benefit from living in these places, but the study’s lead author, Justin Suracy, a senior scientist at Conservation Science Partners and a former postdoctoral fellow at the University of California, Santa Cruz says that’s not necessarily. the case. While raccoons can thrive in developed regions by finding food in our litter boxes and avoiding predators, a higher rate of activity by cougars in the same places could mean something entirely different.
“Not because these advanced areas are really good for Puma,” said Soraci. “It is likely that the reason for this is that the camera traps are positioned in a single track that a poor cougar can use as he works his way through a very advanced scene.” In other words, some of the animals in the study may be active or increasingly present on cameras close to human evolution just because few natural habitats remain.
However, there were certain features that appeared in the species as clear livelihood benefits within the development footprint. In general, the smaller and faster mammals to reproduce, along with general diets, were the ones that were most positively associated with growth. The researchers speculated that they might find similar results when comparing camera capture data based on the level of human presence, but in reality positive and negative responses to the human presence of the species have been observed across the spectrum of body size and diet.
Elk were less likely to survive in places frequented by humans, and moose, mountain goats, and wolverines were less active in these habitats. On the other hand, bighorn sheep, black bears, and wolverines were more likely to be found in areas frequented by humans, while mule deer, bobcat cats, gray foxes, cougars and wolves were more active.
One trend that may influence these findings is the growth of outdoor recreation, increasing the presence of people in the more distant and wild landscapes. The results of the research may indicate that most mammals are willing to withstand some level of human recreation to survive in higher quality habitats, and could instead increase their nocturnal activity to avoid humans. Some animals may even benefit from walking paths and fire paths as easy movement paths.
But the study also clearly showed that there is a limit to how much humans influence animals. Even in species that were more active or more likely to be found in humans or in developed regions, those effects peaked at low to moderate levels of human disturbance and then began to decline past these thresholds. Red foxes were the only animals in the study that found they were more active or present with moderate to high levels of human disturbance.
Ultimately, most species have something to lose and gain by being around humans and understanding how the costs outweigh the benefits for each species will be important to maintaining appropriate habitats that support diversity in mammal populations in the future. Soraci says this is the new paper’s most important contribution.
“From a management perspective, I think the thresholds that we are starting to set will be really relevant,” he said. “This can help us recognize how much habitat is actually available for re-colonization or reintroduction of species, and hopefully it will allow us to coexist more effectively with wildlife in human-controlled landscapes.” (Ani)
