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Human impacts on ecosystems

Review your understanding of human impacts on ecosystems with this free article aligned to NGSS standards.

Key terms

Habitat lossA reduction in liveable space and resources within an ecosystem
PollutionThe introduction of a harmful substance or other disruptive component into the environment
Invasive speciesA non-native species that becomes established in an area and causes harm to native communities
Overexploitation of resourcesThe human consumption of natural resources at a rate greater than what the environment can support or replenish
Climate changeA long-term shift in typical regional or global weather patterns, often attributed to global warming

The human population continues to grow rapidly

Advances in technology have allowed humans a unique advantage over any other species on the planet: the ability to overcome the stresses of global carrying capacity, or the limit to the number of individuals the planet can support. As a result, human populations continue to grow. This population growth means that humans use more and more resources, which has significant implications for the health of Earth’s ecosystems.

Human activities can have significant effects on ecosystems

Many of the changes that occur in ecosystems can be described as anthropogenic, or occurring as a result of human activity. The following list describes five of the most significant anthropogenic effects on ecosystems today.
  • Habitat loss occurs through land-use changes, such as the clearing of a forest to plant crops, and through activities, such as mining, that directly destroy natural landscapes.
  • Pollution occurs when harmful substances enter the environment. Examples of pollutants include disruptive light or noise from human activities, or harmful chemical wastes. For example, the nitrogen in fertilizer runoff can induce the rapid overgrowth of algae in oceans. These algal blooms choke the surrounding waters of available oxygen, resulting in dead zones, or nutrient-depleted regions that can't support plant or animal life.
  • Invasive species are species that have become established in a new environment, typically as a result of human travel or trade. These non-native species can prey on native species, or outcompete native species for resources. Invasive species often lack natural predators in their new environment, so their populations tend to grow quite large, disrupting the balance of the existing ecosystem.
  • The overexploitation of natural resources directly correlates with the need to provide food and housing to an ever-growing human population. Overfishing, for example, removes fish from the oceans faster than they can be replaced through reproduction, stressing the balance of the ecosystem. Burning fossil fuels and cutting old-growth forests are other examples of overexploitation, as these resources can’t be replaced once they are gone.
  • Climate change describes a long-term shift in global weather patterns. While climate change is a global phenomenon, it has significant effects at the regional level. For example, the climate in some temperate regions has shifted and is now characterized by hotter summers and less annual rainfall. Climate change is occurring relatively quickly (in terms of geologic time), putting species that can’t adapt to changing conditions at risk of extinction. The changes in global climate we are seeing today can be attributed primarily to human activities (such as the burning of fossil fuels) that lead to global warming.

What else should I know about human impacts on ecosystems?

Humans can have positive impacts on the environment, too! There are many things humans can do on the individual, community, organization, or government level to positively impact ecosystems. For example, to help address overexploitation of marine resources, individuals can purchase certified sustainable seafood and support government legislation that promotes responsible fishing.
Keep researching and talking with your family, teachers, and friends to come up with more ways that you can have positive impacts on the environment.

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