biology zoology blog benno meyer animal landscapers

Animal Landscapers

Not to be underestimated

One tends to think of the human being as the one who shapes, alters, creates and destroys landscapes. Yet, there are numerous species of animals small and large that can have an enormous impact on the environment by changing the flow of rivers, by creating deserts, by making sand and, yes, even by setting fires to savannahs or forests.

Beavers with their sometimes 500 m long and 4 m high dams are known to have been responsible for dramatic, large-scale changes affecting the flow patterns and directions of rivers. Beavers have created lakes, have stopped rivers from flowing, and have selectively removed certain types of trees from river banks; in short they have had an impact on landscapes that rivals that of mankind. Voles, too, by making holes into dams and levees have had an impact on riverside environments in some areas and goats, of course, are notorious for having caused tremendous changes in some places, where they alone can be held responsible for the creation of deserts, the disappearance of plant life and the lowering of the water table. Such goat-dependent effects were particularly strong on islands.

Game-passes, in use by wild animals for thousands of years, frequently served early human inhabitants of an area as paths and even now they are usually the safest way in underdeveloped regions to get around through the thicket of the jungle or to cross the labyrinth of a swamp. Quite likely some of the ancient game-passes became our present road systems and highways, “autobahns” and railway tracks. Elephants have been credited with creating clearings in otherwise dense vegetation, digging for water with their tusks and spreading seeds with their dung.

Other seed-carrying mammals and birds must be mentioned as they too have done their bit to spread landscaping plant species to regions that water and wind could not have reached. In Northern Australia bush fires have been reported to be caused by the fire-hawk, a bird that has been reported carrying in its talons a glowing piece of wood it picked up from a fire elsewhere and then drops it over an unburnt patch of land in order to drive out lizards and other small prey it can subsequently feast on. And in Australia, as in other warm countries, termites with their timber removing activities and their mounds are affecting landscapes.

We humans may think that we have shaped the world alone, but a great deal of shaping was done by others before us, and last but not least, I have to mention tropical beaches and those reef-forming corals of the tropical seas. These slowly-growing, sessile animals, known as corals, have built breakwaters, atolls, lagoons and islands with their exoskeletons of limestone. Were it not for these small, colonial polyps, several nations on Earth simply would not exist. And for those holiday makers seeking white tropical sandy beaches, they too would not find such beaches, for the latter are also largely a product derived from the coral, their limestone skeletons to be precise. It has been calculated that parrot fishes, which exclusively feed on corals, digest only the soft material of the coral, but pass out the indigestible inorganic limestone material as sand: 1-2 tons of sand per fish per year! It is largely thanks to these fishes and their appetite for corals that we have the beautiful white beaches of fine sands in the tropics.

© Dr V.B. Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com, 2020.
Unauthorized use and/or duplication of this material without express and written permission from this site’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to V.B Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com with appropriate and specific direction to the original content.

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