Currents of Life, Rivers of Change 11 July 2013
Juvenile Fasciated Tiger Heron, Sarapiqui River, Costa Rica
Rivers shape our world. Seasonal floods recharge the landscape with nutrients, and animals readily use rivers as food-rich corridors for dispersal and migration. Humans are no exception. Our largest cities often build upon rivers, and human cultural epicenters have been defined by the character of the rivers upon which they grow. In so many ways, rivers drive the evolution of life on earth.
Abstract Waters, Sarapiqui River
Great-tailed Grackle, Tarcoles River, Costa Rica
Great Egret, Tarcoles River
Some are clean, some are turbid, some are swift, some are slow, and some have been nearly loved to death. Each major river has its own current, its own course, and its own natural history to tell. Naturally muddy, crystal clear, or ravaged by agricultural runoff and urban effluent, the assemblages of plants and animals along a river, both visible above the surface and hidden below, represent a collection of interdependent adaptations unique to the river and ever sensitive to the changes along the watercourse.
American Crocodile, "croc walk", Tarcoles River, Costa Rica
American Crocodile, View from the Bridge, Tarcoles River
Amid rivers of change, crocodiles have changed very little. Here since before the dinosaurs, crocodiles have transcended the eons, witnesses to mass extinction after mass extinction. They can scavenge as well as ambush, can fight off the most brutal of bacterial assaults with blood rich in natural antibiotics, and they can go without food for over a year. In a strange twist of fate, the success of human beings along the rivers of the world holds the potential for being the first catastrophic change crocodiles will be unable to survive.
While the American Crocodile is very large, capable of attaining weights of a ton and lengths of over six meters, it is not larger than human industrial change. And while it is also very dangerous, sometimes taking human life without feeling, it is a rich and mysterious part of the Earth's history that is in greater peril by the hands of humankind. In recent years, conservation biology efforts around the world have rallied around crocodiles and alligators and, in some places, have helped restore an ancient beauty to the life of the river.
American Crocodile
The Tarcoles River in Costa Rica hosts some of the greatest density of large crocodiles in the world, and certainly in the Americas. In some places, more than fifty crocodiles inhabit a square mile. Ecotourism dollars are dollars well spent. When a local economy thrives because people give money to see the beautiful and fascinating animals of a wild ecosystem, the incentive to protect the resource is great. Paying local guides is one way to support protection of wildlife, but there are also unusual guardians. At the head of the bridge above the Tarcoles River, a bustling fruit stand benefits continually from giant crocs. The fruit stand provides a place for people to park cars before walking out onto the narrow bridge. With such a great diversity of unusual and inviting fruits, dried foods, jellies and a line of colorful sarong fabrics, money quickly changes hands. A steady run of new customers will park and arrive minute by minute, day by day, so long as there are crocodiles to see in the waters below. The fruit stand employs a very sincere guard to watch over parked cars while tourists are away, and so the masses walk out to pay their respects to an ancient and impressive ambush predator. As much out of thanks as out of curiosity, people return with a smile and head to the fruit stand. As the crocodiles live their lives in the river below, a fast flow of cash seems to ensure some kind of a future for the flow of life on the river below. Do currents of currency ensure currents of wild waters?
As much as crocodiles have survived change, durable through all that nature can deliver, they now serve as a protector of the wild. In a strange twist, it is this same human species that has threatened them the most that will work to protect them in the future. Through such protection, the crocodiles become a financially motivating keystone species. So, while the crocs have witnessed so many extinctions over the millions of years, they are perhaps now unwitting agents of extinction prevention. So long as there are crocodiles in the rivers, money will change hands at a rate that may encourage the protection of those rivers and their ecosystems. In the right light, done in a sustainable way, the health of an economy will lead to its environmental prosperity.
All images were made with a refurbished Canon 7D and 300mm f4L IS lens, and a Canon 28-135 IS lens. A Canon electronic cable release and Gitzo basalt tripod with ball head were used to make the long exposures of the tiger heron on the Sarapiqui River. Special thanks to all in Costa Rica who continue to protect the wild!
