Researching the impact of roads in the amazon jungle

Walking 2 hours on a dusty road with trees felled to the side and the sun blazing overhead is not your typical day in the rainforest. Unfortunately, it is for us who are studying the effects of this road that serves as a stark contrast and constant reminder of the influence humans can have in a once pristine habitat in the Yachana Reserve, Ecuador. Today, it’s butterflies we’re surveying, setting up baited traps at various distances from the road to see what species are found close, and what species are found far from the road. We’ve finally hit the relief of trees, canopy, and shade as we head in to the forest and set up our first trap. The bait isn’t pretty: rotten fish, fermented in a closed jar in the heat of a tropical rainforest for over a week. Unfortunately for our noses, butterflies, especially less common ones, seem to love it.

I have heard this story told from rainforests throughout the world: Where there was once a small hiking trail to a distant community 4 hours away now lies a wide road with electrical poles, trees cleared along the side, and even asphalt. While the progress for the community can be immeasurable in access to medical care, increased standard of living, and ease of selling produce, the long-term damage that a road can cause to a rainforest’s animals has simply never been measured. Roads serve as a tangible representative of development and disturbance in the area. As more people live in an area and more products are created to sell, the more a need for a bigger, better, safer road there is.

As roads get used more, studies have shown the following not-so-great things tend to happen and can have a long lasting affect deep into the forest:

• Illegal hunting and illegal logging increase as access to forest increases, severely affecting the large mammal populations and deforestation rates.
• The fragmentation to the habitat can limit the forest from access by species that need large, undisturbed ranges like jaguars, large bird of prey, or monkeys.
• Roadkill incidences increase, affecting animal populations, range, and genetic diversity.
• Temperature of asphalt increases, likely affecting road kill rates, animal cross overs, and genetic diversity.
• Runoff pollution of chemicals from cars, tires increases.
• Trash pollution by people dumping/throwing trash increase.
• Noise pollution increases by loud engines increases, proven to be detrimental to bird populations.
• Invasive, weedy plant species are more likely to encroach.

Today, and for the past few months, we are watching it unfold right in front of us. While it was once a beautiful narrow road with canopy touching overhead in some parts, it now has much less you could call beautiful. With areas extending as far as 200 feet from the road cleared to allow electricity lines, the road is wide, dry, and bordered by countless fallen trees.

In our situation, we’re hoping to measure the change in road (narrow to wide) as a change in animal populations surrounding the road, then, now, and when the asphalt comes. We’re surveying birds, butterflies, reptiles, amphibians, and mammals to see if we get different levels of diversity and different species closer to the road compared to further from the road. We’re in the middle of data collection for the widened road state, spending hours in the field each day and night catching, identifying, and measuring animals.

As roads leading up to Tambopata demonstrate, Peru is no stranger to road impacts. This study being done in Ecuador will hopefully help future policy and engineering decisions about how, and where, to build roads in or near such rainforests. With the IIRSA roads built across Peru and more being asphalted, the increased impact of humans is bound to be occurring. Let’s hope for responsible government decisions that will keep the roads benefitting the humans in need while minimizing the impact.

See more articles by biologist Phil Torres at wwwTheRevScience.com