This tinkering with nature in crop production not only affects human health, but the health of the environment from which it grows and its dependent ecosystem. "Perhaps the most poignant risk from genetically modified plants occurs at the environmental level" ("What you should know About Genetically Modified Foods" http://environmentalcommons.org.) As noted in the study of the soil from the genetically modified crops above, once genetically modified seeds are introduced to an area, there is nothing known to science today on how to reverse the effects of its contamination. This is because GMOs cross pollinate and can spread throughout the environment by means of the wind, insect pollination or other methods of transfer. "The foreign genes can cross with and contaminate these other species, resulting in a hybridization of the genetically modified crop plant with a non-GMO plant. This could radically alter entire ecosystems if the hybrid plants thrived" (The Dangers of GMOs http://www.naturalnews.com.)
Other studies have proved that pesticide producing crops can contaminate nearby streams, therefore effecting aquatic life. Because the BT toxin that is produced by genetically modified crops are stronger than any found in nature, beneficial insects such as bees and butterflies are harmed. "Bees are hugely important in the pollination of many food crops, but are unfortunately extremely endangered by modern agricultural techniques, such as GM crops. Monarch butterflies are specifically at risk from GMO maize plants. In addition to bees and butterflies, birds are also at risk from pesticides, and work as biological control agents and pollinators" (The Environmental Impact of GMOs" http://www.onegreenplanet.org.) The connection lies in genetically modified seeds lead to genetic modification of the flower pollen. The pollen that is modified can cause the bees to become malnourished and die due to lack of nutrients and an interrupt the bee's digestion process.
Finally, biodiversity is put at risk by GMOs because when they are planted, many heritage seeds are no longer used. "The nature of GMOs means fewer weed flowers and, therefore, less nectar for pollinators. Toxins released into the soil through the plants´ routes mean fewer soil bacteria, which are integral to healthy soil for plants to grow without the use of chemical fertilizers. Toxic residues are left in the soil of GM crops. Nutrients are not returned to the soil in mono crops and from GMO foods, meaning that soil is becoming dry and void of all nutrients, generally integral to the growing process. A cycle of dependence on GMO seeds and chemical fertilizers, pesticides, and herbicides is then created in order to grow a single crop. In addition to soil issues, the irrigation used to grow GM foods naturally carries all of these problems into water sources and into the air. This exposes different bacteria, insects, and animals to the same problems" ("The Environmental Impact of GMOs" http://www.onegreenplanet.org.)