Professional poachers undoubtedly give little thought to anything beyond the desired immediate response to their nefarious acts, namely a monetary return. Aside from not dwelling on skirting the law, they are unlikely to care about their inhumane treatment of wildlife. The odds are also against them being concerned about potentially triggering an ecological chain reaction culminating in species extinction.
Poachers challenge the premise that all human beings possess cognitive superiority to predatory lower life forms whom ecologists are confident don't look past the dietary gratification of their latest kill.
It may be unwittingly on the part of these lower life forms, but natural selection steers them towards bolstering the healthy perpetuation of the very biodiversity that "successful" poachers jeopardize. For example, lions on the plains of East Africa generally kill no more than necessary to ease their immediate hunger pangs. In the process, they cull just enough to keep their prey's population from exploding and overrunning the habitat.
By contrast, if left to their own devices, ivory obsessed elephant poachers would not desist until they had sliced the tusks off every last pachyderm.
In Africa alone, there were 10 million elephants a century ago. Today, an estimated 500,000 remain, and they are vanishing at a faster rate than they can reproduce. Habitat loss from human encroachment has contributed to some of the precipitous decline, but most of the 20,000 African elephants killed in 2013 were victims of poaching (which accounted for more than three million slain tuskers between 1950 and 1990).
Unlike lower life forms, human beings are not supposed to be prisoners of the moment, thanks to their cognitive capabilities.
Poachers belie this stereotype by strongly suggesting that if given the chance, they would be willing "to kill the goose that lay the golden egg". Certainly they seem oblivious to the havoc they are wreaking on an ecological system that supports them (and their families).
As seed dispersers, elephants are crucial to the existence of native plants in the region, and by extension, the animal life that relies upon such vegetation. Elephants also create clearings in the forest that provide essential habitat for species that would otherwise not survive, as well as diminish the breeding grounds for the malaria-carrying tsetse fly.
Fortunately, not all humans are as insensitive to the ecological cycle of life as are poachers. In the case of elephants, various forms of protection have been imposed, ranging from hunting prohibitions (enforced in varying degrees) to destruction of illegal ivory caches, education to discourage the ivory trade, and controlled sustainable harvesting of the animals and their tusks. One would think if consumer demand for ivory can't be curbed, salvaging the tusks from elephants that have died of natural causes would at last spare the slaughter of these magnificent sentient creatures.