Question

Identify the interactions as positive, negative, or both.

A mudslide wipes out the side of a thriving hill:
A volcano erupts, covering the nearby land with lava:
A forest is rapidly growing new plant life:
Humans remove wolves from a national park to protect surrounding homes:
A dam is built in the middle of a river ecosystem to supply water to a nearby town:

Answer 1

1. A mudslide wipes out the side of a thriving hill: Both — negative for the existing community (habitat loss, mortality) but can create opportunities for pioneer species and succession over time.
2. A volcano erupts, covering the nearby land with lava: Both — immediate devastation for local life, but long-term soil formation and new habitats can be beneficial.
3. A forest is rapidly growing new plant life: Positive — increases resources and habitat for many organisms (though it could disadvantage species that need open areas).
4. Humans remove wolves from a national park to protect surrounding homes: Both — benefits humans (reduced risk to homes/people) but harms wolves and can cause negative ecosystem effects (trophic cascades).
5. A dam is built in the middle of a river ecosystem to supply water to a nearby town: Both — provides human benefits (water supply, hydroelectricity) while negatively impacting river ecology (altered flow, migration barriers, sediment changes).