"[E]cosystems do not only have value aesthetically and prudentially, they also have disvalue. In aesthetic terms, few of us enjoy the sight of animals dying through starvation or disease. And many of us also recoil rather than feel a sense of wonder at the reality of predation. And, as we have seen, ecosystems also possess prudential disvalue. As well as improving the well-being of sentient animals of which they are a part, they also facilitate their suffering. This means that if we value ecosystems for the the beauty and the well-being they afford, we cannot object to interventions which interfere with and change those ecosystems if they increase that beauty and well-being. In other words, then, it appears that sometimes out duty may be to protect ecosystems, and at other times it may be to interfere with them."