Feral pigs and donkeys may be more salvation than scourge for ecosystems, study finds
An unscientific bias against “feral” or “invasive” animals threatens to undercut one of the great stabilizing trends making ecosystems healthier, a new paper argues.
Reintroducing feral animals benefits ecosystems
A new study published in Science argues that introduced species such as feral pigs, horses, donkeys, and camels play a vital role in rewilding ecosystems. These animals, whether they are considered invasive or native, contribute to plant diversity, spread seeds, and function as ecosystem engineers. The study challenges the conventional wisdom about the harmful effects of invasive species and suggests that the focus should be on the size and dietary preferences of the animals, rather than their origin.
The authors of the study examined over 200 studies on the impact of large herbivores on ecosystems and found no significant differences between introduced and native megafauna. They argue that the negative effects attributed to invasive species are often overstated, and that these animals have partly counteracted the decline in big plant-eating mammals experienced since prehistory. Instead of eradicating these species, the study suggests that they should be recognized for their environmental benefits.
The role of native and introduced animals in ecosystem engineering
The study highlights the importance of understanding the effects of animal behavior and its impact on ecosystems. Animals like native pigs and feral cousins in America and Polynesia have similar behaviors, including rooting up plants, defecating on landscapes, and creating wallows. While these actions may seem destructive, they also have positive environmental effects. For instance, the rooting up of plants creates space for new growth, the nutrients in animal feces serve as natural fertilizer, and wallows act as tiny ponds to trap and retain water in dry landscapes.
The study draws parallels between the actions of these animals and the behaviors of long-extinct species from the ice age, demonstrating the potential ecological benefits of their presence. It challenges the idea that only native species are beneficial to ecosystems and emphasizes the need for a more nuanced understanding of the complex interactions between animals and their environment.
The political and philosophical aspects of managing animal populations
The study concludes by acknowledging that decisions about managing animal populations are not purely scientific, but also political and philosophical. The distinction between native and introduced species is often a matter of personal beliefs and values. While scientists can provide evidence on the impact of these animals, the final decision on their removal or protection lies with society. The study calls for transparency in decision-making processes and a recognition that values and preferences play a significant role.
The debate surrounding invasive species has been complex, with arguments for and against the eradication of non-native animals. The study challenges the prevailing bias against invasive species and suggests that a more comprehensive understanding of their ecological effects is necessary. It highlights the importance of considering the environmental benefits that these animals bring and the potential consequences of their removal.
