All together, there are 3-4 generations of monarch butterfly each year. A very small number of monarchs overwinter in pine trees at a few sites along the Gulf coast of Florida, near Tampa and possibly west of Tallahassee. Several factors threaten the overwintering sites in Mexico. Many forests are being destroyed by loggers, an industry that threatens so many species worldwide. Also, due to the ever-increasing human population, expansion of villages into the overwintering sites is creating problems.
Pesticides pose yet another threat to the monarch population.
Ecotourism, which sometimes can create money to support species' conservation, is negatively affecting the monarch population because human presence is disruptive to the monarch's fragile ecosystem. Due to the number of threats to the monarch populations, only time will tell if yet another species will be destroyed by the unfortunate practices of an uncaring, exponentially-growing human population. Primack, R. B. 1993. Essentials of Conservation Biology. May 1996 .