Final answer:
The expansion of species 1's distribution following the removal of species 2 indicates that competition with species 2 was limiting its distribution, illustrating the competitive exclusion principle.
Step-by-step explanation:
If species 1's distribution expands after species 2 is removed from the area, this would indicate that the distribution of species 1 was previously limited due to competition with species 2. This outcome is consistent with the competitive exclusion principle, which states that two species cannot indefinitely occupy the same ecological niche in the same environment because intense competition will lead to the local extinction of one or the evolution of different niches.
In the absence of species 2, if species 1 shows increased growth, reproduction, or expansion in territory, it would strongly suggest that interspecific competition was a key factor limiting its distribution.