1. Early Human Impact:
* The Pleistocene Extinction (~10,000 years ago): This period saw the extinction of many large mammals (megafauna) across the globe. While climate change played a role, human hunting and competition for resources likely contributed significantly.
2. Modern Era (Last Few Centuries):
* Habitat Destruction: As human populations grew, we began to clear vast areas for agriculture, development, and urbanization, destroying habitats for countless species.
* Overhunting and Overfishing: This was a major factor in the decline of many species, particularly in the 19th and 20th centuries, as demand for certain animal products increased.
* Pollution: Industrial and agricultural activities release pollutants that contaminate air, water, and soil, harming animals.
* Invasive Species: The introduction of non-native species can disrupt ecosystems and lead to the decline of native species.
* Climate Change: This is a rapidly escalating threat, altering habitats, changing weather patterns, and causing ocean acidification, impacting animal populations worldwide.
So, while it's difficult to put a precise date on the beginning of endangerment, it's clear that the issue has been escalating with human activities for thousands of years and is now accelerating at an alarming pace.