Final answer:
True, human activities like logging and overexploitation can significantly affect multiple populations within an ecosystem, leading to altered interactions and possibly threatening the ecosystem's integrity and services.
Step-by-step explanation:
The statement 'They may affect several populations in the ecosystem' is true. Factors like logging, grazing, and changes in disturbance regimes can modify habits and affect the growth of populations within an ecosystem. An example from Kibale National Park shows that the blue monkey populations were negatively impacted by logging, while black and white colobus populations thrived in regrowth forests. These deterministic processes have significant effects on both plant and animal species in fragmented ecosystems.
Moreover, the overexploitation of natural resources can lead to populations that are so diminished that they no longer significantly interact with other species in their community. Such changes may result in the degradation of the ecosystem's complexity, and reduce the services it provides to other species and the environment. This concept also extends to habitat destruction in aquatic ecosystems, where modifications like damming can severely reduce or eliminate populations that depended on the natural flow.