NRDC: Hybrid Law
Q&A with Andrew Wetzler, co-director of NRDC’s Land and Wildlife Program and an expert on the Endangered Species Act and legal issues regarding threatened and endangered species, including the polar bear.
Does the increasing number of hybrids in the Arctic present a concern for the preservation of endangered or threatened species?
Yes, hybridization can be a real problem for some endangered species. (See "Grolar Bears and Narlugas: Rise of the Arctic Hybrids.") For example, the Northern Spotted Owl has suffered from hybridization in recent decades. When a species hybridizes, its gene pool can be compromised or even lost. Eventually, the "species" you were trying to protect simply doesn’t exist anymore.
Does the Endangered Species Act take into account concerns about the potential loss of species through hybridization?
The text of the Endangered Species Act itself doesn’t mention the problem of hybridization or suggest how it should be dealt with, but the U.S. Fish and Wildlife Service has adopted numerous policies to try to address the problem over the years. In particular, one thorny question is: what is the status of the hybrid offspring of an endangered species? Should hybrid offspring be protected under the act or not? After going back-and-forth on this question, the federal government has settled on a case-by-case approach, which makes sense. Sometimes it’s in the best interest of a species to protect hybrids, but sometimes it’s not.
Does genetic purity play any role in determining endangered species status?
Genetics can play a huge role in determining whether a population of animals or plants really is a separate "species" or "subspecies" and thus qualifies for protection under the act. NRDC senior scientist Sylvia Fallon actually published a study on this question and found that genetic studies have a huge impact on what plants and animals ultimately get protected. (See "The Little Mouse That Got in the Way" from OnEarth’s Winter 2007 issue.)
Does the confirmation of polar bear/grizzly hybrids have any impact on legal issues involving the polar bear?
Probably not. While it’s a troubling trend, and could be evidence of the impact global warming is already having on the Arctic, the polar bear case will ultimately turn on issues other than hybridization.