ES 10 - Introduction to Environmental Science
                 (Student Reflection Papers)

2. Another reflection on ecology - Daphne P. Villanueva (BS ME, ES10-E, 2nd Sem 2000-2001)gives her insights on how something which was thought to be a solution sometimes end up to be more of a problem than the original problem.

 

Toxic toads threaten north Australia

          FROGS. Repulsive. Puny. Insignificant. Lethal. The fourth adjective seems to be outrageously incongruous to the preceding three. Note that this is neither a typographical error nor a desperate attempt of achieving an even number of adjectives.

          Because of its relatively minuscule structure, it would sound rather absurd that such creatures may actually be a destructive element to the environment. The only reason they are able to grasp attention is due to their abominable physique and its trademark croaks. Aside from these characteristics, they are not given desirable responses from the human species. Perhaps the invasion of poisonous cane toads is its way of informing mankind of its actual purpose in the world. This specie therefore aims to prove that its fatality more than makes up for their lack in size.

          The mass infiltration of these cane toads will drastically affect the lifestyles of indigenous species in the park, presumably to the point of rendering an increase death rate in population growth. Despite its ability to carry toxic secretions in their sacs is its quantity. Imagine a truckload of these noxious toads rampaging through a forest abundant with sensitive native communities.

          It has been discussed in class that the population growth curve primarily experiences a lag phase, an exponential phase, and finally a stationary growth. This stationary growth occurs when the deathrate equals the birthrate, where the growth will come to a halt and a stable population size is achieved. This information is rightly applicable to the population growth of aboriginal species in the Australian park. The invasion of toxic cane toads will serve as the catalytic element that will enable a relatively rapid approach of the population to its stationary growth. Deathrate will easily equal the birthrate of the victim species because of the quantity of the toads. In addition, once poison is released from their sacs, it is only a matter of minutes before it kills its �prey�.

          In line with this concept is the carrying capacity of a population. Besides the major factors such as availability of raw materials, availability of energy, accumulation of wastes and interaction among organisms, the carrying capacity is greatly influenced by limiting factors such as low food supply, disease, predators and limited space, among others. These environmental resistances will determine the number of organisms that can be present in a given area within a time period. The cane toads may be considered as predators that will no doubt limit the population size of native communities. However, the carrying capacity may be increased if this limiting factor is removed. This does not look too optimal at the moment because �the remote park�s extensive rivers and swamps are too difficult to defend�.

          According to the report, these cane toads were introduced to Australia in order to prey on cane beetles that were damaging crops. The people who pioneered this specie into the particular area failed to accurately calculate the consequences these toads may instigate, thus triggering disarray that never would have occurred were it not for their improper interference.

 

Data Source:
Toxic toads threaten north Australia, British Broadcasting Corporation, 19 January 2001

 

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