What is Conservation Biology?

A wetland is drained for agriculture, and the local frog population collapses. Which threat to biodiversity does this illustrate, and what conservation strategy could help?

The frogs lost the physical place they live and breed in, so this is habitat loss.
Habitat loss is the single largest cause of biodiversity decline worldwide.
An in-situ strategy — protecting or restoring the remaining wetland as a reserve — directly addresses the cause.
Habitat corridors could also reconnect isolated wetland patches so frog populations can interbreed.

A rare orchid species has only 40 individuals left in the wild due to poaching. Botanists collect seeds and grow the plants in a botanical garden. What type of conservation is this, and why is it used here?

Because the plants are being protected outside their natural habitat, this is ex-situ conservation.
Ex-situ methods are used when a species is at critical risk of extinction in the wild.
Growing plants in a controlled botanical garden protects genetic material and allows population recovery.
Surplus plants can later be reintroduced into protected wild habitat once poaching threats are reduced.

An invasive predator is introduced to an island and starts eating the eggs of a native, flightless bird found nowhere else. Identify the threat and one management response.

This is the introduction of an invasive species, a major driver of extinction on islands.
Island species often evolve without natural predators, so they have few defenses.
A management response is eradicating or controlling the invasive predator (e.g. trapping programs).
Captive breeding (ex-situ) can also be used as a safety net while the island habitat is restored.