Final answer:
A species needs a dispersal corridor, an available niche on the new continent, and a short travel distance for interbreeding to successfully cross a land connection and colonize another continent. Additionally, overcoming barriers to establishment greatly contributes to colonization success.
Step-by-step explanation:
For a species to successfully cross a land connection and colonize another continent, there are certain conditions that are necessary. These conditions include:
- A dispersal corridor with conditions that the species can survive traveling through, such as continuous "corridors" or "stepping stones" of habitat or relatively benign human land-uses that facilitate movements.
- An available niche on the new continent that meets the species' ecological and biological needs.
- A short travel distance that permits interbreeding between new and ancestral populations, maintaining gene flow and reducing the effects of isolation.
- Potentially, a higher-quality habitat on the new continent, although this is not always a determining factor as species may also colonize habitats of similar or less quality if other conditions allow.
Furthermore, the ability of a species to overcome barriers to establishment, and either supplement existing populations through immigration or emigrate to form new ones, plays a crucial role in colonization success.