The effect of lampposts on the spotted cat population
David Ref
Among the victims of the separation fence - the one that stretches between the state of Texas in the south of the United States and Mexico - is also the spotted cat (Ocelot). The purpose of the fence is to prevent illegal immigration and smuggling of goods, but the noisy patrols, fences and artificial lighting are severely damaging the ecosystem along the border.
The spotted cat is a relatively small predator, whose average weight is 10 kilograms. It is widespread mainly in Central America and the south (up to northern Argentina and Chile). In North America the spotted cat used to be common in Florida, Arkansas and Arizona. Today, several individuals live in these areas. Most of the spotted cat population in the United States is currently limited to South Texas. Researchers estimate that it only has about 120 individuals.
Hundreds of thousands of spotted cats were killed in the last century for their fur. About 13 bodies are required to make one fur coat, and many hunters set out to provide the goods. In the 140,000s and 30s, hunting reached its peak - about XNUMX individuals were killed every year. Laws for the protection of nature, which were enacted in the USA about XNUMX years ago, resulted in a considerable reduction in the trade in the furs of spotted cats on its land. On the other hand, there was almost nothing to hunt anymore.
In Texas the spotted cats live in several nature reserves. According to economists' estimates, the economic growth in the counties where the reserves are located is the highest in Texas in recent years. With the acceleration of urban development in the area, and mainly due to the construction of obstacles along the border, the crossings between the nature reserves and between the US and Mexico are becoming more and more complicated for the spotted cats. Their ability to search for prey and reproduce is impaired.
These conclusions were presented in January of this year in an article published in the journal "Urban Ecosystems", which is published in the Netherlands. The title of the article is "The Effect of Artificial Light on the Spotted Cat" and it provides many statistical data, collected since 1946, both on the spotted cat and on the animals it feeds on along the Rio Grande River, which flows alongside the border between the countries.
More than 400 lampposts were erected in this area, along about 65 kilometers of border. Various studies have shown that small rodents may change their nocturnal activity under conditions of artificial lighting. It was found that night lighting, whose brightness exceeds the average light on a full moon night, causes certain species of rodents to reduce their activity or even stop it altogether. The authors of the article also refer to a study done on a group of cougars in California, from which it emerged that under conditions of artificial lighting, the animals preferred to move their activities to dark areas.
The authors of the article assume that the spotted cat, active mainly between eight in the evening and five in the morning, was also forced to change the route of its search for prey and move to relatively dark areas. These have been dwindling in recent years. The article's conclusions are bleak. It appears from them that if the accelerated construction and the construction of obstacles along the border continue, without finding solutions for wildlife, soon there will be no more spotted cats in the United States.
