Impacts of Pesticides on Wildlife

Photo by Steve Hillebrand, U.S. Fish and Wildlife Service

The impacts of pesticides on wildlife are extensive, and expose animals in urban, suburban, and rural areas to unnecessary risks. Beyond Pesticides defines "wildlife" as any organism that is not domesticated or used in a lab. This includes, but is not limited to, bees, birds, small mammals, fish, other aquatic organisms, and the biota within soil. Wildlife can be impacted by pesticides through their direct or indirect application, such as pesticide drift, secondary poisoning, runoff into local water bodies, or groundwater contamination. It is possible that some animals could be sprayed directly; others consume plants or prey that have been exposed to pesticides.

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Pesticide exposure can be linked to cancer, endocrine disruption, reproductive effects, neurotoxicity, kidney and liver damage, birth defects, and developmental changes in a wide range of species. Exposure to pesticides can also alter an organism’s behavior, impacting its ability to survive. In birds, for example, exposure to certain pesticides can impede singing ability, making it difficult to attract mates and reproduce. Pesticides can also affect birds' ability to care for offspring, causing their young to die.  For bees, even “near-infinitesimal” levels of systemic pesticides result in sublethal effects, impacting mobility, feeding behaviors, and navigation.  

Many deformations have been found after exposure to hormone-mimicking pesticides classified as endocrine disruptors. The impacts of these chemicals include hermaphroditic deformities in frogs, pseudo-hermaphrodite polar bears with penis-like stumps, panthers with atrophied testicles, and intersex fish in rivers throughout the U.S. Reproductive abnormalities have been observed in mammals, birds, reptiles, fish, and mollusks at exposure levels considered “safe” by the U.S. Environmental Protection Agency (EPA).

Visit our Pesticide Gateway for more information about specific pesticides and their impacts on wildlife.


Biodiversity is the web of life, including the complex array of organisms that live in the environment, and their interactions and interdependencies. The functionality of biodiversity has deep significance for the nurturance and protection of the many individual species in the environment that are part of a greater whole. The impacts of pesticides on wildlife directly relate back to the functional aspects of biodiversity. The Earth’s rich biological heritage of species, communities, and ecosystems, which have evolved across millions of years, is rapidly deteriorating and in many instances irreversibly disappearing. The impacts of pesticides on wildlife is a major cause of concern in the deterioration of biodiversity. 

It has been documented that certain pesticides, when introduced to aquatic environments, cause a decline in species diversity in aquatic organisms and predatory insects. In Europe, it has been found that a 42% loss in species richness occurs due to pesticide exposure, even when such exposures are at concentrations deemed environmentally safe by current legislation. Species richness of beneficial insects, such as bees, spiders, and beetles, has been found to be much higher on untreated or organic fields than on those treated with insecticides. Use of insecticides is a common occurrence in chemical-dependent agriculture.

Organic pest management sharply contrasts with a chemical-intensive approach in terms of its impact on the stability and resiliency of ecosystems. This divergence has enormous consequences for biodiversity and survival of wild species. Various land management practices have different effects on the web of life; recognition of this is crucial to maintaining the intricate balance and life-sustaining benefits of nature. Utilizing organic pest management rather than chemical-intensive controls is the most critical step in mitigating negative impacts of pesticides on wildlife and preserving the Earth’s remaining biodiversity.

Economic Impacts of Pesticides on Wildlife

The estimated economic costs of losses to biodiversity — for the value of pollinator services, “beneficial” predators, and birds and aquatic life — are continually changing as more complex and comprehensive studies are published. Earlier studies estimated that the cost of losses to biodiversity might amount to more than $1.1 billion annually. Now, we know that the loss of biodiversity can cost hundreds of billions of dollars annually. Natural pest control, a fundamental agricultural service, is estimated to be worth $100 billion annually. The role of soil biota in increasing agricultural productivity is worth $25 billion annually. By 2009, the value of dependent crops attributed to all insect pollination was estimated to be worth $15.12 billion annually.

Photo by Pierre Mineau, Canada

Other economic impacts are related to the recreational use of wildlife. U.S. citizens already spend over $60 billion annually on hunting, fishing, and observing wildlife; much of the wildlife at the center of those activities depends on insects as a food source. Researchers have found that there is a steady decline in these insects due to pesticide exposure and an overall decline in biodiversity. It could be concluded then that, as beneficial insect populations decline, their ability to provide ecosystem services will also decline, impacting the available wildlife for hunting, fishing and observing. The demand for these recreational activities will stay constant while the supply (availability) will decline, causing an increase in dollars spent by U.S. citizens for each year.

Organic Systems Protect Wildlife

Two ways to combat the negative impacts of pesticides on wildlife are: to implement organic practices for your own lawn and garden, and to support organic agriculture, rather than on conventional agriculture, which relies on pesticide use. Beyond Pesticides supports organic agriculture as effecting good land stewardship and reducing wildlife's hazardous chemical exposures. The pesticide reform movement, citing pesticide problems associated with chemical agriculture — from groundwater contamination and runoff to drift — views organic as the solution to these serious environmental threats.

Conventional agriculture relies on a “pick and choose” method when it comes to pesticide use — only treating the symptoms of bad land management instead of acknowledging the deeper problems and attempting to understand agriculture as a whole system, including impacts on wildlife. Adopting a whole-systems approach, starting with management methods that “feed-the-soil,” and thus, promote healthy land from the ground up, would result in the greatest systemic benefit. Beyond Pesticides has long supported a “feed-the-soil” approach to agricultural management. This systems approach, which centers on managing soil health and on proper fertilization, eliminates synthetic fertilizers and focuses on building the soil food web and nurturing soil microorganisms. Experience demonstrates that this approach develops a soil environment rich in microbiology, which will produce resilient, productive land and benefit wildlife.

Healthy, resilient soil reduces any need for pesticides; terrain free from pesticides benefits wildlife and promotes natural predators, who can then do what they were meant to do in nature — provide natural controls. Organic systems save wildlife from the dangerous impacts of pesticides, encourage them to flourish, and restores the natural balance that is unable to exist in a conventional agricultural system.

Utilizing the Endangered Species Act and Other Laws to Protect Wildlife

One way that groups like Beyond Pesticides have sought to protect wildlife from the threat of pesticides is by holding federal agencies accountable to the Endangered Species Act (ESA) of 1973, which provides for the conservation of ecosystems on which threatened and endangered species of fish, wildlife, and plants depend. EPA has routinely disregarded the ESA’s requirement to consult with federal wildlife agencies on how to implement conservation measures to protect threatened and endangered species from pesticides. After years of gridlock, federal wildlife agencies, EPA, and the U.S. Department of Agriculture (USDA) asked the National Academy of Sciences to study the issue and report on best ways to protect listed species (any species likely to become endangered or which is in danger of extinction) from the effects of toxic pesticides. The National Academy of Sciences report identified deficiencies for all the agencies involved in pesticide consultations, but singled out the EPA’s approach for its numerous analytical shortcomings. In response to the Academy’s recommendations, the agency announced several reforms, in the fall of 2013, designed to protect endangered species more effectively.

A stranded fish at Murray's Cauld near Selkirk
Photo by Walter Baxter

Though the ESA is one of the most important laws for protecting wildlife, the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), Clean Water Act (CWA), and National Environmental Policy Act (NEPA) are other significant laws meant to keep wildlife safe. FIFRA regulates pesticides to prevent “unreasonable adverse effects” to humans and the environment, including wildlife. The stated objective of the CWA is to “restore and maintain the chemical, physical, and biological integrity of the Nation’s waters . . . for the protection and propagation of fish, shellfish, and wildlife.”

Finally, NEPA requires that any federal government action that may impact wildlife and the environment must review and evaluate those impacts before any action is taken. Each of these laws can be utilized to protect wildlife by holding federal agencies accountable to them. For more detailed information about each law and how it protects wildlife, read "Preserving Biodiversity As If Life Depends on It," from our winter 2011–2012 Pesticides and You newsletter.

See below for successful litigation regarding pesticides and wildlife:
EPA Agrees to Regulate Novel Nanotechnology Pesticides after Legal Challenge (March 2015)
Final Suit Routing Genetically Engineered Crops and Related Practices from Refuges (March 2015)
Following Lawsuit, EPA Restores Stream Buffers to Protect Salmon from Pesticides (August 2014)

See below for current litigation regarding pesticides and wildlife:
EPA’s Expansion of 2,4-D Enlist Duo Challenged (April 2015)
EPA Violates FIFRA, ESA and APA (March 2013)

Other Resources:

The Dangers of Pesticides to Wildlife
Getting the Drift on Chemical Trespass
Pesticides That Disrupt Endocrine System Still Unregulated by EPA
Preserving Biodiversity As If Life Depends On It
Environmental and Economic Costs of the Application of Pesticides Primarily in the United States
The Real Story on the Affordability of Organic Food
Protecting Life: From Research to Regulation