The rationale and motivation for conserving mantellas falls into two broad areas:

THE EMOTIONAL REASON: INTRINSIC VALUE AND AESTHETICS

Here, the premise is that mantellas should be conserved simply because they exist and are part of the reality we find ourselves in and a part of. To lose them from the Earth would be a loss to us all. We derive pleasure from their beauty; and their loss would deny us that.

THE PRAGMATIC REASONS: VALUE TO BIODIVERSITY AND SCIENTIFIC KNOWLEDGE

Recent studies have shown (I will provide references) that greater biodiversity tends to be correlated with greater ecosystem stability, with the opposite also being true. Thus all components of an ecosystem's biodiversity (such as the mantellas in the Madagascan rainforest) are important for that ecosystem's continued stability. Ecosystems provide mankind with valuable resources (food, medication, etc) and services (clean air and water). Clearly, therefore, it is in our best interests to protect the safe functioning of our ecosystems as best we can, and attempting to maintain the Earth's biodiversity is a valuable process.

Mantellas also have much to contribute to the advancement of scientific knowledge. For example, to studies of animal conservation (where they may serve as model systems for other species), animal behaviour, and natural toxin chemistry, to name but a few. Were mantellas to become extinct those opportunities for increasing our scientific knowledge (which is in itself both intrinsically valuable by definition, and valuable from a pragmatic sense) would be lost.

GOD TELLS US TO

Another reason which I've only recently become aware of is that God tells us to do so. Our global environment is in a sorry state and the Bible tells us that this is because we live in a fallen world. In Hosea, chapter 4 (verses 1-3) we read: 1 Hear the word of the LORD, you Israelites, because the LORD has a charge to bring against you who live in the land: "There is no faithfulness, no love, no acknowledgment of God in the land. 2 There is only cursing, lying and murder, stealing and adultery; they break all bounds, and bloodshed follows bloodshed. 3 Because of this the land mourns, and all who live in it waste away; the beasts of the field and the birds of the air and the fish of the sea are dying." While the most important thing we can do in response to this is to turn back to God, trying to be responsible stewards of God's creation is also important.