The Threat of Road Expansion to Forest Elephants
Due to private enterprise and the desire of Central African governments to become more industrialized there has recently been a large expansion of roads into the rainforests of the Congo basin where forest elephants make their home. These roads are built for easier access to the high quality lumber and minerals found in the forest but they also make it more accessible to poachers and increase conflict between the animals and local people¹.
In one study conducted in the Congo basin, 28 forest elephants living in high priority conservation areas were tracked using GPS telemetry. The elephants were found to be much more likely to cross roads that were located in protected areas than in unprotected ones. In fact, only one elephant from the sample crossed a road outside a protected area. This elephant crossed the road at the furthest distance possible from the nearest village and walked 14 times faster than her usual pace while crossing it. In contrast, elephants crossing roads located inside protected areas increased their walking rate only slightly¹. The researchers concluded that the caution exhibited by the elephants was due to fear from poaching. This makes sense since other studies have found an increase in the number of poached elephant carcasses near roads².
Another study conducted in the Congo basin found that the density of elephants in a protected area depended not on how big it was but rather on how many roads were inside it. It also found that there were more elephants at all distances from roads in protected areas than in unprotected ones².
The elephants’ fear of crossing roads results in subpopulations becoming isolated which may cause inbreeding and a reduction in overall genetic health. It also results in reduced access to natural resources, which forces the animals to overexploit small patches of land, thereby increasing aggression and lowering reproductive success¹.
Since these studies were conducted, the problem has become progressively worse. In three of six sites used in the first study there have been very large losses in roadless wilderness. There are also a few multibillion dollar development projects that threaten even more road construction¹.
The authors of these studies suggest that, in order to mitigate their impact, roads should not be built in high priority conservation areas such as those that give elephants access to natural resources or that connect subpopulations. If it is necessary to extract resources from these high priority areas, temporary roads should be built which can be taken down once the extraction is finished. They also propose that fear of the roads can be reduced by directing more funding towards anti-poaching law enforcement and preventing conflicts between the elephants and local people¹.
References:
¹Blake, Stephen, Sharon L. Deem, Samantha Strindberg, Fiona Maisels, Ludovic Momont, Inogwabini-Bila Isia, Iain Douglas-Hamilton, William B. Karesh, and Michael D. Kock. “Roadless wilderness area determines forest elephant movements in the Congo Basin.” PloS one 3, no. 10 (2008): e3546. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0003546
²Blake, Stephen, Samantha Strindberg, Patrick Boudjan, Calixte Makombo, Inogwabini Bila-Isia, Omari Ilambu, Falk Grossmann et al. “Forest elephant crisis in the Congo Basin.” PLoS Biol 5, no. 4 (2007): e111.
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0003546
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Conserving the tropical forests of Africa through acoustic monitoring, sound science, and education, focusing on forest elephants
