Tree Snails Released Back to Polynesia After 30 Years: Can They Restore Ecological Balance?

“In the month of April in the year 2023, a grand total of 5,000 Polynesian tree snails (hereinafter referred to as tree snails) embarked on a momentous journey spanning an astounding distance of 15,000 kilometers by means of air travel. Their final destination was none other than the majestic islands of Moorea and Tahiti, nestled within the enchanting realm of French Polynesia. These resplendent snails, on the brink of extinction upon the Polynesian isles, have been the subject of unwavering scientific endeavors spanning three decades, all aimed at restoring their vibrant existence.

Tree snails, indigenous denizens of the Polynesian islands, possess a diminutive stature, measuring less than 2.5 centimeters in length. Yet, their profound significance within the local ecology is truly colossal. With an insatiable appetite for fungi and decaying flora, these remarkable creatures play a vital role in curtailing the adverse impact on plants. Fungi, ever tenacious, swiftly convert nutrients from residual plant matter, such as fallen leaves, rejuvenating the soil. Consequently, they emerge as indispensable agents in the harmonious functioning of forest ecosystems.

But what, one may ponder, led to the near-extinction of these tree snails upon these idyllic islands? The origins of this predicament trace back to the 1960s when the gastronomically-inclined French introduced gargantuan snails to the shores of French Polynesia. Irony struck, as these colossal snails, who were meant to grace the kitchens of French gourmands, orchestrated a remarkable escape, proliferating uncontrollably throughout the local environs. Feeding upon over 500 varieties of plants and bereft of natural adversaries, these ravenous invaders voraciously devoured the indigenous flora, resulting in severe consequences for the island’s fragile ecosystem.

In an attempt to quell the rampant multiplication of these colossal snails, the French authorities introduced a natural predator, the wolf snail, to the areas infested by the gargantuan invaders. However, the wolf snail, in its voracious pursuit of delectable prey, not only decimated the large, sumptuous snails but also targeted a multitude of diminutive local snails, including the invaluable tree snails that played a pivotal role in sustaining the island’s delicate ecosystem. The wolf snail, in its relentless march, nearly obliterated the native tree snail population.

The Reintroduction of Tree Snails

Tree snails, as they stand, represent an integral component of the local ecosystems, their presence of paramount importance.

The introduction of novel species driven by culinary desires has resulted in a disquieting disarray within the indigenous ecology.

Several minuscule islands, bereft of tree snails, have borne witness to a cataclysmic degradation of their ecosystems. Prior to the disappearance of the tree snails, harmony reigned supreme within the agricultural lands and forests, existing in perfect equilibrium. However, following the vanishing act of the tree snails, not only did the forests suffer an egregious decline, but the fertility of the agricultural lands diminished as well, compelling local farmers to expand their territorial claims in order to meet their subsistence requirements. Regrettably, this pursuit has only led to further encroachment of the forests onto farmland.

In an earnest endeavor to salvage the ecological integrity of the Polynesian islands, a group of dedicated scientists commenced their noble mission during the 1990s. Collecting the remaining tree snails from the local environs, they embarked upon the path of artificial breeding, ensuring the continued existence of the tree snail species. Fortuitously, their tireless efforts bore fruit, culminating in the preservation of 11 distinct subspecies of tree snails through the means of meticulous artificial breeding.

Since the year 2014, a gradual process of releasing these artificially bred tree snails back into the embrace of the Polynesian islands has been underway. The most recent release, transpiring in the month of April 2023, welcomed a staggering contingent of 5,000 avian companions. Cumulatively, the total number of tree snails reintroduced thus far has reached an impressive tally of 21,000. In order to monitor the progress of the tree snail release, scientists have judiciously adorned each tree snail’s back with a vivid crimson mark, infused with fluorescent properties. Illuminated by ultraviolet light, these distinctive markings serve as a beacon, greatly assisting scientists in their noble task of enumerating the tree snail populace thriving within the wild. Multiple field surveys conducted post-release have resoundingly indicated that the laboratory-raised tree snails have swiftly adapted to the very forests that once sheltered their ancestors.

It is an established fact that the introduction of exotic species can precip the ecological balance of an area, and this rapid and dramatic imbalance can cause many native species to quickly disappear. Can the reintroduction of native tree snails succeed in restoring ecological balance? Next, let’s look at the tree snails.