Understanding Reasons for Biodiversity Losses

Biodiversity refers to the variety of life on Earth at all its levels, from genes to ecosystems, and encompasses the ecological and evolutionary processes that sustain life. Unfortunately, biodiversity is facing significant threats, leading to its loss. Several factors contribute to this decline. The question asks which of the given reasons can cause biodiversity losses.

Let's analyze the two points provided:

1. Alien species invasion
2. Co - extinctions

Biodiversity Loss Reason 1: Alien Species Invasion

When alien (or exotic or non-native) species are introduced into a habitat where they did not previously exist, either intentionally or unintentionally, they can become invasive. Invasive alien species can pose a major threat to native biodiversity for several reasons:

• They can outcompete native species for resources like food, water, and space.
• They can prey on native species.
• They can introduce new diseases or parasites that native species have no resistance to.
• They can alter the habitat, making it unsuitable for native species.
• They can hybridize with native species, potentially leading to the extinction of the native species' unique genetic identity.

Many examples exist globally where invasive alien species have caused severe declines or even extinctions of native plants and animals, proving that alien species invasion is a significant reason for biodiversity losses.

Biodiversity Loss Reason 2: Co - extinctions

Co-extinction is a phenomenon where the extinction of one species leads to the extinction of another. This often occurs when species are tightly linked in an ecological relationship. For instance:

• A parasite species might only be able to survive on a specific host species. If the host species goes extinct, the parasite species will also likely go extinct because its only habitat and food source are gone.
• An obligate pollinator species (like a specific insect) might be the only animal capable of pollinating a particular plant species. If the plant species disappears, the pollinator may also go extinct.

These dependent relationships mean that losing one species in the pair or chain results in the loss of the other, contributing directly to biodiversity losses.

Conclusion on Biodiversity Loss Reasons

Both alien species invasion and co-extinctions are well-documented and significant drivers of biodiversity loss worldwide. Alien species invasion disrupts ecosystems through competition, predation, disease, and habitat alteration. Co-extinctions occur when species are ecologically dependent on each other, and the loss of one triggers the loss of another.

Therefore, both points listed are valid reasons for the loss of biodiversity.